SYSTEMS AND METHODS FOR A SPLIT EXHAUST ENGINE SYSTEM

Abstract

Method comprising: under conditions during which the amount of opening of an intake throttle (62) is below a threshold amount of opening: directing intake air from an intake duct (28) to a second exhaust manifold (80) coupled to a second set of cylinder exhaust valves (6) via an exhaust gas recirculation (EGR) duct (50), including closing the intake throttle (62); heating the intake air as it passes through an EGR cooler (52) in the EGR duct (50); directing the heated intake air to an intake manifold (44) downstream of an intake throttle (62) via a flow channel (30) coupled between the second exhaust manifold (80) and the intake manifold (44); and removal of combustion gases via a first set of cylinder exhaust valves (8) to a first exhaust manifold (84) which is coupled to an exhaust channel (74).

Description

Area The present description generally concerns methods and systems for a split exhaust gas internal combustion engine that includes exhaust gas recirculation. General state of the art / Summary Internal combustion engines can use charging devices, such as turbochargers, to increase their power density. However, this can lead to engine knocking due to increased combustion temperatures. Knocking is particularly problematic under intensified conditions due to high charge temperatures. DE 10 2016 111 686 A1 discloses methods and systems for a supercharged engine with a split exhaust system. DE 10 2015 111 793 A1 discloses methods and systems for operating an engine in a diagonal two-valve blow-through mode, in which a majority of the blow-through is directed through a first intake valve positioned diagonally opposite a first exhaust valve to increase the length of the flow path from the intake valve to the exhaust valve. DE 100 84 733 T5 discloses an internal combustion engine with exhaust gas recirculation. The inventors of the present invention have recognized that using an internal combustion engine system with a split exhaust system, wherein a first exhaust manifold directs exhaust gas to a turbine of the turbocharger in an exhaust port of the internal combustion engine and wherein a second exhaust manifold directs exhaust gas recirculation (EGR) to an inlet of the internal combustion engine upstream of a compressor of the turbocharger, reduces knocking and increases internal combustion engine efficiency. In such an internal combustion engine system, each cylinder can include two inlet valves and two exhaust valves, wherein a first set of cylinder exhaust valves (e.g., blow-off exhaust valves), which are exclusively connected to the first exhaust manifold, can be operated at a different time than a second set of cylinder exhaust valves (e.g., scavenging exhaust valves), which are exclusively connected to the second exhaust manifold, thereby isolating a scavenging section and a blow-off section from the exhaust gases.The timing of the second set of cylinder exhaust valves can also be coordinated with the timing of the cylinder intake valves to create a positive valve overlap period, during which fresh intake air (or a mixture of fresh intake air and EGR), also known as purge air, can flow through the cylinders and back to the intake upstream of the compressor via an EGR channel coupled to the second exhaust manifold. Purge air can remove residual exhaust gases from within the cylinders (also known as scavenging). The inventors of the present invention have recognized that the combustion temperatures can be reduced by allowing a first portion of the exhaust gas (e.g., higher-pressure exhaust gas) to flow through the turbine and a higher-pressure exhaust channel, and by allowing a second portion of the exhaust gas (e.g.,Exhaust gas (with lower pressure) and blow-through air to the compressor inlet can be reduced, while improving the turbine's operating efficiency and the internal combustion engine torque. However, the inventors have recognized potential problems with such systems. For example, in a gas reaction state (where an intake throttle is at least partially closed), the flow into the EGR channel can be reversed, and intake air can be introduced into the internal combustion engine cylinders via the EGR channel. This can cause reduced mixing and a reduced cylinder equilibrium. The inventors have further recognized that an EGR valve located within the EGR valve can be closed to reduce backflow through the system. However, this can increase the pressure in the scavenging exhaust manifold and the residual gases remaining in the internal combustion engine cylinders. In one example, the problems described above can be addressed by a procedure that includes: directing intake air from an intake manifold to a second exhaust manifold coupled to a second set of cylinder exhaust valves via an exhaust gas recirculation (EGR) channel; heating the intake air as it passes through an EGR cooler in the EGR channel; directing the heated intake air to an intake manifold downstream of an intake throttle via a flow channel coupled between the second exhaust manifold and the intake manifold; and expelling combustion gases through a first set of cylinder exhaust valves to a first exhaust manifold coupled to the exhaust port. As an example, this directing of intake air can occur in response to the intake throttle opening falling below a threshold value (e.g., in a gas reaction state).In this way, cylinder pumping work during the gas reaction state can be reduced. Furthermore, heating the intake air via the EGR cooler can increase MAP (manifold absolute pressure), reduce intake pumping, and thus improve fuel efficiency and reduce emissions. This process can also increase the mixing of EGR from each cylinder with the incoming intake air, thereby reducing the effect of any single cylinder on EGR mixing and reducing resistance, as well as manifold optimization. It is understood that the foregoing summary is provided to present, in simplified form, a selection of concepts that are described in more detail in the full description. It is not intended to mention important or essential features of the claimed subject matter, the scope of which is defined solely in the claims following the full description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages noted above or in any part of this disclosure. Brief description of the drawings Fig. 1A shows a schematic representation of a turbocharged internal combustion engine system with a split exhaust system. Fig. 1B shows an embodiment of a cylinder of the internal combustion engine system from Fig. 1A. Fig. 2A shows a block diagram of a first embodiment of an internal combustion engine air-fuel ratio control system and an air-fuel ratio control system for the air flowing into an exhaust emission device. Fig. 2B shows a block diagram of a second embodiment of an internal combustion engine air-fuel ratio control system and an air-fuel ratio control system for the air flowing into an exhaust emission device. Fig. 3A shows exemplary cylinder intake and exhaust valve timings for an internal combustion engine cylinder of a split exhaust internal combustion engine system.Figure 3B shows exemplary adjustments of the intake and exhaust valve timing for one cylinder of the split exhaust combustion engine system for various engine operating modes. Figures 4A-4B show a flowchart of a method for operating a split exhaust combustion engine system, wherein a second exhaust manifold directs exhaust gas and blow-through air to an intake of the engine system and a first exhaust manifold directs exhaust gas to an outlet of the engine system, under various vehicle and engine operating modes. Figure 5 shows a flowchart of a method for operating the split exhaust combustion engine system in a cold-start mode. Figure 6 shows a flowchart of a method for operating the split exhaust combustion engine system in a deceleration fuel cut-off mode.Figures 7A-7B show a flowchart of a method for operating the split exhaust gas combustion engine system in a gas reaction mode. Figure 8 shows a flowchart of a method for operating the split exhaust gas combustion engine system in an electrical amplification mode. Figure 9 shows a flowchart of a method for operating the split exhaust gas combustion engine system in a compressor threshold mode. Figure 10 shows a flowchart of a method for operating the split exhaust gas combustion engine system in a baseline blowthrough combustion cooling (BTCC) mode. Figure 11 shows a flowchart of a method for diagnosing one or more valves of the split exhaust gas combustion engine system based on the scavenging manifold pressure.Figure 12 shows a flowchart of a method for controlling the EGR flow and blow-through air from a scavenging manifold via the adaptation of the operation of one or more valves of the exhaust gas combustion engine system to an intake port. Figure 13 shows a flowchart of a method for selecting between operating modes to adapt a flow of exhaust gases from the combustion engine cylinders via scavenging exhaust valves and a scavenging exhaust manifold of the split exhaust gas combustion engine system to an intake port. Figure 14 shows a flowchart of a method for operating a hybrid electric vehicle incorporating the split exhaust gas combustion engine system in an electric mode. Figure 15 shows a flowchart of a method for operating the split exhaust gas combustion engine system in a shutdown mode.Figure 16 shows an exemplary diagram of changes in the internal combustion engine operating parameters during operation of the split exhaust gas combustion engine system in a cold start mode. Figure 17 shows an exemplary diagram of changes in the internal combustion engine operating parameters during operation of the split exhaust gas combustion engine system in a fuel cut-off (DFSO) mode. Figures 18A-18B show an exemplary diagram of changes in the internal combustion engine operating parameters during operation of the split exhaust gas combustion engine system in a gas reaction mode. Figure 19 shows an exemplary diagram of changes in the internal combustion engine operating parameters during operation of the split exhaust gas combustion engine system in an electric boost mode.Figure 20 shows an exemplary diagram of changes in internal combustion engine operating parameters during operation of the split exhaust combustion engine system in a compressor threshold mode. Figure 21 shows an exemplary diagram of changes in the pressure and oxygen content of a scavenging exhaust manifold over a single engine cycle of the split exhaust combustion engine system. Figure 22 shows an exemplary diagram for controlling one or more internal combustion engine actuators to adjust the exhaust gas recirculation (EGR) flow and the blow-through flow from the scavenging exhaust valves of the internal combustion engine cylinders to an intake port of the split exhaust combustion engine system. Figure 23 shows an exemplary diagram for operating a hybrid electric vehicle in an electric mode to heat the split exhaust combustion engine system prior to starting the internal combustion engine.Figure 24 shows an exemplary diagram of changes in the internal combustion engine operating parameters during operation of the split exhaust combustion engine system in a shutdown mode. Figure 25 shows an exemplary diagram of the operation of the split exhaust combustion engine system from start-up to shutdown. Detailed description The following description concerns systems and methods for operating a split exhaust gas internal combustion engine with blow-through and exhaust gas recirculation (EGR) via a second exhaust manifold to an intake. As shown in Fig. 1A, the split exhaust gas internal combustion engine may include a second exhaust manifold (referred to herein as a scavenging manifold) coupled exclusively to a scavenging exhaust valve of each cylinder. The scavenging manifold is coupled via a first EGR channel, which includes a first EGR valve (referred to herein as a BTCC valve), to the intake port upstream of a turbocharger compressor. The split exhaust gas internal combustion engine also includes a first exhaust manifold (referred to herein as a blow-off manifold) coupled exclusively to a blow-off exhaust valve of each cylinder.The blow-off manifold is coupled to an exhaust port of the internal combustion engine, the exhaust port containing a turbocharger turbine and one or more emission control devices (which may include one or more catalysts). In some embodiments, the split exhaust engine system may include additional ports coupled between the blow-off manifold and either the intake or exhaust port, as shown in Fig. 1A. Additionally, in some embodiments, the split exhaust engine system may include various valve actuation mechanisms and may be installed in a hybrid vehicle, as shown in Fig. 1B. Due to the multiple exhaust manifolds and the various couplings of the blow-off manifold to the intake and exhaust ports, the split exhaust engine may incorporate a unique air-fuel control system, as shown in Figs. 2A-2B.The scavenging and blow-off valves open and close at different times during an internal combustion engine cycle for each cylinder to isolate the scavenging and blow-off components of the combusted exhaust gases and direct these components separately to the scavenging and blow-off manifolds, as shown in Fig. 3A. The timing of the intake valve, scavenging valve, and blow-off valve for each internal combustion engine cylinder can be adjusted to increase EGR and / or blow-off to the intake and / or to optimize engine performance under different engine operating modes, as shown in Fig. 3B. The timing of different valves and cylinder intake and exhaust valves of the split exhaust combustion engine system can be controlled differently under different combustion engine operating conditions, as shown in Figures 4A-4B. For example, different operating modes of the split exhaust combustion engine system can include an electric mode (a method for this mode is shown in Figure 14 and a corresponding exemplary time-course curve is shown in Figure 23), a cold-start mode (a method for this is shown in Figure 5 and a corresponding exemplary time-course curve is shown in Figure 16), a deceleration cut-off mode (a method for this mode is shown in Figure 6 and a corresponding exemplary time-course curve is shown in Figure 17), and a gas-reaction mode (a method for this mode is shown in Figures 4A-4B).7A-7B (and a corresponding exemplary time-course curve is shown in Figs. 18A-18B) include an electrical gain mode (a method for this mode is shown in Fig. 8 and a corresponding exemplary time-course curve is shown in Fig. 19), a compressor threshold mode (a method for this is shown in Fig. 9 and a corresponding exemplary time-course curve is shown in Fig. 20), a shutdown mode (a method for this mode is shown in Fig. 15 and a corresponding exemplary time-course curve is shown in Fig. 24), and an outlet blow-through combustion cooling (BTCC) mode (a method for this mode is shown in Figs. 10-13 and corresponding exemplary time-course curves are shown in Figs. 21 and 22). During an operating period of the internal combustion engine (e.g.,From an ignition key start to an ignition key shut-off, the split exhaust gas combustion engine system can transition between several of the operating modes described above. An example of such an engine operating period, from engine start to shutdown, is shown in Fig. 25. In this way, the engine actuators of the split exhaust gas combustion engine system can be controlled differently based on the current operating mode of the engine system, in order to increase engine efficiency and reduce engine emissions in each engine operating mode. In the following description, a valve that is operational or activated indicates, according to specific times during the combustion cycle for a given set of conditions, that it is open and / or closed. Similarly, a valve that is deactivated or inoperative indicates that the valve remains closed unless otherwise specified. Fig. 1A shows a schematic representation of a multi-cylinder internal combustion engine 10, which can be integrated into a motor vehicle's propulsion system. The internal combustion engine 10 comprises a plurality of combustion chambers (i.e., cylinders), which may be covered on top by a cylinder head (not shown). In the example shown in Fig. 1A, the internal combustion engine 10 comprises cylinders 12, 14, 16, and 18 arranged in a four-cylinder in-line configuration. However, it is understood that although Fig. 1A shows four cylinders, the internal combustion engine 10 can include any number of cylinders in any configuration, e.g., V-6, I-6, V-12, opposed four, etc. Furthermore, the cylinders shown in Fig. 1A can have a cylinder configuration such as that shown in Fig. 1B, as described below.Each of the cylinders 12, 14, 16, and 18 includes two intake valves, including the first intake valve 2 and the second intake valve 4, and two exhaust valves, including the first exhaust valve (hereinafter referred to as a blow-off exhaust valve or blow-off valve) 8 and the second exhaust valve (hereinafter referred to as a scavenging exhaust valve or scavenging valve) 6. The intake valves and exhaust valves may be referred to herein as cylinder intake valves and cylinder exhaust valves, respectively. As explained below with reference to Fig. 1B, a timing (e.g., opening time, closing time, opening duration, etc.) of each of the intake valves may be controlled by different camshaft timing systems. In one embodiment, both the first intake valves 2 and the second intake valves 4 may be controlled to the same valve timing (e.g., so that they open and close at the same time in the internal combustion engine cycle).In an alternative embodiment, the first intake valves 2 and the second intake valves 4 can be controlled to a different valve timing. Furthermore, the first exhaust valves 8 can be controlled to a different valve timing than the second exhaust valves 6 (e.g., so that a first exhaust valve and a second exhaust valve of the same cylinder open and close at different times than the other), as discussed below. Each cylinder receives intake air (or a mixture of intake air and recirculated exhaust gas, as discussed below) from an intake manifold 44 via an intake port 28. The intake manifold 44 is connected to the cylinders via intake ports (e.g., pipes). For example, as shown in Fig. 1A, the intake manifold 44 is connected to each first intake valve 2 of each cylinder via first intake ports 20. Furthermore, the intake manifold 44 is connected to each second intake valve 4 of each cylinder via second intake ports 22. In this way, each cylinder intake port can selectively communicate with the cylinder to which it is connected via one of the first intake valves 2 or the second intake valve 4. Each intake port can supply air and / or fuel to the cylinder to which it is connected for combustion. One or more of the intake ports may include a charge motion control device, such as a charge motion control valve (CMCV). As shown in Fig. 1A, each first intake port 20 of each cylinder includes a CMCV 24. CMCVs 24 may also be referred to as swirl control valves or tumble control valves. CMCVs 24 can restrict the airflow entering the cylinders through the first intake valves 2. In the example from Fig. 1A, each CMCV 24 may include a valve plate; however, other valve designs are possible. For the purposes of this disclosure, it is important to note that when fully activated, the CMCV 24 is in the "closed" position, and the valve plate can be fully tilted into the corresponding first intake port 20, resulting in maximum charge flow obstruction.Alternatively, the CMCV 24 is in the “open” position when deactivated, and the valve plate can be fully rotated to be substantially parallel to the airflow, thereby significantly minimizing or eliminating airflow charge obstruction. The CMCVs can, in principle, be kept in their “open” position and can be activated in the “closed” position only when swirl conditions are desired. As shown in Fig. 1A, only one intake port of each cylinder incorporates the CMCV 24. However, in alternative embodiments, both intake ports of each cylinder can incorporate a CMCV 24. The control 12 can actuate the CMCVs 24 (e.g.,via a valve actuator, which may be coupled to a rotating shaft directly coupled to each CMCV 24, to move the CMCVs in response to internal combustion engine operating conditions (such as engine speed / load and / or when blow-through via the second exhaust valves 6 is active) to the open or closed position, or a variety of positions between open and closed, as discussed further below. As defined herein, blow-through air or blow-through combustion cooling may refer to intake air flowing from one or more intake valves of each cylinder to the second exhaust valves 6 (and into the second exhaust manifold 80) during a valve overlap period between the intake valves and the second exhaust valves 6 (e.g., a period when both the intake valves and the exhaust valves 6 are open at the same time). A two-stage high-pressure fuel system (such as the fuel system shown in Fig. 1B) can be used to generate fuel pressures at the injection devices 66. Fuel can then be injected directly into the cylinders via the injection devices 66. A distributorless ignition system 88 provides a spark to cylinders 12, 14, 16, and 18 via the spark plug 92 in response to the control unit 12. Cylinders 12, 14, 16, and 18 are each connected to two exhaust ports for the separate routing of the blow-off and scavenging portions of the combustion gases. In particular, as shown in Fig. 1A, cylinders 12, 14, 16 and 18 discharge the combustion gases (e.g., scavenging section) to the second exhaust manifold (hereinafter referred to as a scavenging manifold) 80 via second exhaust lines (e.g., openings) 82) and the combustion gases (e.g., blow-off section) to the first exhaust manifold (hereinafter referred to as a blow-off manifold) 84 via first exhaust lines (e.g., openings) 86.The second exhaust pipes 82 extend from cylinders 12, 14, 16, and 18 to the second exhaust manifold 80. Additionally, the first exhaust manifold 84 includes a first manifold section 81 and a second manifold section 85. The first exhaust pipes 86 of cylinders 12 and 18 (hereinafter referred to as the outer cylinders) extend from cylinders 12 and 18 to the second manifold section 85 of the first exhaust manifold 84. Additionally, the first exhaust pipes 86 of cylinders 14 and 16 (hereinafter referred to as the inner cylinders) extend from cylinders 14 and 16 to the first manifold section 81 of the first exhaust manifold 84. Each exhaust pipe can selectively communicate with the cylinder to which it is coupled via an exhaust valve. For example, secondary exhaust pipes 82 communicate with their corresponding cylinders via secondary exhaust valves 6, and the first exhaust pipes 86 communicate with their corresponding cylinders via first exhaust valves 8. The secondary exhaust pipes 82 are isolated from the first exhaust pipes 86 when at least one exhaust valve of each cylinder is in a closed position. Exhaust gases cannot flow directly between the exhaust pipes 82 and 86. The exhaust system described above may be referred to herein as a split exhaust manifold system, wherein a first portion of the exhaust gases from each cylinder is discharged to the first exhaust manifold 84, and a second portion of the exhaust gases from each cylinder is discharged to the second exhaust manifold 80, and wherein the first and second exhaust manifolds do not communicate directly with each other (e.g.,No channel directly connects the two exhaust manifolds, and therefore the first and second parts of the exhaust gases do not mix within the first and second exhaust manifolds. The internal combustion engine 10 includes a turbocharger comprising a two-stage exhaust turbine 164 and an intake compressor 162, coupled on a common shaft. The two-stage turbine 164 comprises a first turbine 163 and a second turbine 165. The first turbine 163 is directly coupled to the first manifold section 81 of the first exhaust manifold 84 and receives exhaust gases only from cylinders 14 and 16 via the first exhaust valves 8 of cylinders 14 and 16. The second turbine 165 is directly coupled to the second manifold section 85 of the first exhaust manifold 84 and receives exhaust gases only from cylinders 12 and 18 via the first exhaust valves 8 of cylinders 12 and 18. The rotation of the first and second turbines drives the rotation of the compressor 162, which is located within the intake port 28. Thus, the intake air is amplified (e.g., pressurized) at the compressor 162 and moves downstream to the intake manifold 44.The exhaust gases exit both the first turbine 163 and the second turbine 165 into the common exhaust duct 74. A wastegate can be coupled to the two-stage turbine 164. In particular, the wastegate valve 76 can be contained in a bypass 78 that is coupled between each of the first manifold section 81 and the second manifold section 85 upstream of an inlet to the two-stage turbine 164 and the exhaust duct 74 downstream of an outlet of the two-stage turbine 164. In this way, a position of the wastegate valve (hereinafter referred to as a turbine wastegate) 76 controls an amount of boost provided by the turbocharger. In alternative embodiments, the internal combustion engine 10 can include a single-stage turbine, where all exhaust gases from the first exhaust manifold 84 are directed to an inlet of an identical turbine. Exhaust gases exiting the two-stage turbine 164 flow downstream in the exhaust channel 74 to a first emission control device 70 and a second emission control device 72, the second emission control device 72 being located downstream in the exhaust channel 74 from the first emission control device 70. The emission control devices 70 and 72 may, in one example, include one or more catalyst modules. In some examples, the emission control devices 70 and 72 may be three-way catalysts. In other examples, the emission control devices 70 and 72 may include one or more diesel oxidation catalysts (DOC) and selective catalytic reduction catalysts (SCR). In yet another example, the second emission control device 72 may include a gasoline particulate filter (BPF).In one example, the first emission control device 70 can include a catalytic converter and the second emission control device 72 can include a BPF. After passing through the emission control devices 70 and 72, the exhaust gases can be directed out to a tailpipe. The exhaust duct 74 further includes a plurality of exhaust gas sensors in electronic communication with the control unit 12 of the control system 15, as described below. As shown in Fig. 1A, the exhaust duct 74 includes a first lambda sensor 90, which is arranged between the first emission control device 70 and the second emission control device 72. The first lambda sensor 90 can be configured to measure the oxygen content of exhaust gas entering the second emission control device 72. The exhaust duct 74 can include one or more additional lambda sensors positioned along the exhaust duct 74, such as the second lambda sensor 91, which is positioned between the two-stage turbine 164 and the first emission control device 70, and / or the third lambda sensor 93, which is positioned downstream of the second emission control device 72.Thus, the second lambda sensor 91 can be configured to measure the oxygen content of the exhaust gas entering the first emission control device 70, and the third lambda sensor 93 can be configured to measure the oxygen content of the exhaust gas leaving the second emission control device 72. In one embodiment, the one or more lambda sensors 90, 91, and 93 can be wideband lambda (universal exhaust gas oxygen - UEGO) sensors. Alternatively, the lambda sensors 90, 91, and 93 can be replaced by a binary exhaust gas lambda sensor. The exhaust duct 74 can include various other sensors, such as one or more temperature and / or pressure sensors. For example, as shown in Fig. 1A, a pressure sensor 96 is positioned within the exhaust duct 74 between the first emission control device 70 and the second emission control device 72.Thus, the pressure sensor 96 can be configured to measure the pressure of exhaust gas entering the second emission control device 72. Both the pressure sensor 96 and the lambda sensor 90 are located within the exhaust duct 74 at a point where a flow channel 98 couples to the exhaust duct 74. The flow channel 98 can be referred to here as a scavenge manifold bypass passage (SMBP) 98. The SMBP 98 is directly coupled to and between the second exhaust (e.g., scavenge) manifold 80 and the exhaust duct 74. A valve 97 (hereinafter referred to as the scavenge manifold bypass valve - SMBV) is arranged within the scavenge manifold bypass channel 98 and is actuated by the control 12 to adjust an amount of exhaust gas flow from the second exhaust manifold 80 to the exhaust channel 74 at a point between the first emission control device 70 and the second emission control device 72.The second exhaust manifold 80 is directly coupled to a first exhaust gas recirculation (EGR) channel 50. The first EGR channel 50 is directly coupled between the second exhaust manifold 80 and the intake duct 28 upstream of the compressor (e.g., turbocharger compressor) 162 (and can therefore be described as a low-pressure EGR channel). Thus, exhaust gases (or blow-through air, as explained below) are routed from the second exhaust manifold 80 to the intake duct 28 upstream of the compressor 162 via the first EGR channel 50. As shown in Fig. 1A, the first EGR channel 50 includes an EGR cooler 52 configured to cool exhaust gases flowing from the second exhaust manifold 80 to the intake manifold 28 and a first EGR valve 54 (which may be referred to herein as the BTCC valve). The controller 12 is configured to actuate and adjust the position of the first EGR valve 54 to control the amount of airflow through the first EGR channel 50.When the first EGR valve 54 is in a closed position, no exhaust gases or intake air from the second exhaust manifold 80 can flow to the intake duct 28 upstream of the compressor 162. Furthermore, when the first EGR valve 54 is in an open position, exhaust gases and / or intake air from the second exhaust manifold 80 can flow to the intake duct 28 upstream of the compressor 162. The controller 12 can additionally position the first EGR valve 54 in a variety of positions between fully open and fully closed. A first discharge device 56 is positioned at an outlet of the EGR channel 50 within the intake duct 28. The first discharge device 56 may include a constriction or a Venturi that provides a pressure increase at the inlet of the compressor 162. As a result, EGR from the EGR channel 50 can mix with fresh air flowing through the intake duct 28 to the compressor 162. Thus, EGR from the EGR channel 50 can act as the moving flow at the first discharge device 56. In an alternative embodiment, there may be no discharge device positioned at the outlet of the EGR channel 50. Instead, an outlet of the compressor 162 may be shaped as a discharge device that reduces the gas pressure to assist in the EGR flow (and thus, in this embodiment, air is the moving flow and EGR is the secondary flow).In another embodiment, EGR can be introduced from the EGR channel 50 at the trailing edge of a blade of the compressor 162, thereby enabling air to be blown through the EGR channel 50 to the intake channel 28. A second EGR channel 58 is coupled between the first EGR channel 50 and the intake duct 28. In particular, as shown in Fig. 1A, the second EGR channel 58 is coupled to the first EGR channel 50 between the EGR valve 54 and the EGR cooler 52. In alternative embodiments, where the second EGR channel 58 is included in the internal combustion engine system, the system may not include an EGR cooler 52. Additionally, the second EGR channel 58 is directly coupled to the intake duct 28 downstream of the compressor 162. Because of this coupling, the second EGR channel 58 can be referred to herein as a medium-pressure EGR channel. Furthermore, as shown in Fig. 1A, the second EGR channel 58 is coupled to the intake duct 28 upstream of a charge air cooler (CAC) 40. The CAC 40 is configured to cool intake air (which may be a mixture of fresh intake air from outside the internal combustion engine system and exhaust gases) as it passes through the CAC 40.Thus, recirculated exhaust gases from the first EGR channel 50 and / or the second EGR channel 58 can be cooled via the CAC 40 before entering the intake manifold 44. In an alternative embodiment, the second EGR channel 58 can be coupled to the intake duct 28 downstream of the CAC 40. In this embodiment, an EGR cooler 52 may not be arranged within the first EGR channel 50. Furthermore, as shown in Fig. 1A, a second exhaust device 57 can be positioned within the intake duct 28 at an outlet of the second EGR channel 58. A second EGR valve 59 (e.g., a medium-pressure EGR valve) is located within the second EGR channel 58. The second EGR valve 59 is configured to adjust the amount of gas flow (e.g., intake air or exhaust gas) through the second EGR cooler 58. As described below, the controller 12 can actuate the EGR valve 59 to an open position (allowing flow through the second EGR channel 58), a closed position (blocking flow through the EGR channel 58), or a variety of positions between fully open and fully closed based on (e.g., as a function of) internal combustion engine operating conditions.For example, actuating the EGR valve 59 can involve the control unit 12, which sends an electronic signal to an actuator of the EGR valve 59 to move a valve plate of the EGR valve 59 to an open position, a closed position, or a position between fully open and fully closed. As further explained below, based on system pressures and the positions of alternative valves in the internal combustion engine system, air can flow either to the intake port 28 within the second EGR port 58 or to the second exhaust manifold 80 within the second EGR port 58. The intake duct 28 further includes an electronic intake throttle 62 communicating with the intake manifold 44. As shown in Fig. 1A, the intake throttle 62 is positioned downstream of the CAC 40. The position of a throttle plate 64 of the throttle 62 can be adjusted by a control system 15 via a throttle actuator (not shown) that is communicatively coupled to the control system 12. By modulating the air intake throttle 62 during operation of the compressor 162, a quantity of fresh air from the atmosphere and / or a quantity of recirculated exhaust gases from one or more EGR channels can be drawn into the internal combustion engine 10, which is cooled by the CAC 40 and delivered to the internal combustion engine cylinders via the intake manifold 44 at compressor (or boosted) pressure. To reduce compressor pumping, at least some of the air charge compressed by compressor 162 can be returned to the compressor inlet.A compressor recirculation channel 41 can be provided to recirculate compressed air from the compressor outlet upstream of the CAC 40 to the compressor inlet. The compressor recirculation valve (CRV) 42 can be provided to adjust the amount of recirculated flow to the compressor inlet. For example, the CRV 42 can be actuated to open by a command from the controller 12 in response to actual or expected compressor pumping conditions. A third flow channel 30 (which may be referred to herein as a hot pipe) is coupled between the second exhaust manifold 80 and the intake duct 28. Specifically, a first end of the third flow channel 30 is directly coupled to the second exhaust manifold 80, and a second end of the third flow channel 30 is directly coupled to the intake duct 28 downstream of the intake throttle 62 and upstream of the intake manifold 44. A third valve 32 (e.g., hot pipe valve) is located within the third flow channel 30 and is configured to adjust the amount of airflow through the third flow channel 30. The third valve 32 can be actuated to a fully open position, a fully closed position, or a plurality of positions between fully open and fully closed in response to an actuation signal sent from the controller 12 to an actuator of the third valve 32. The second exhaust manifold 80 and / or the second exhaust pipes 82 can contain one or more sensors (such as pressure sensors, temperature sensors, and / or lambda sensors) arranged therein. For example, as shown in Fig. 1A, the second exhaust manifold 80 contains a pressure sensor 34 and a lambda sensor 36, which are arranged therein and configured to measure the pressure and oxygen content, respectively, of exhaust gases and intake air exiting the second exhaust valves 6 and entering the second exhaust manifold 80. In addition to or as an alternative to the lambda sensor 36, each second exhaust pipe 82 can contain an individual lambda sensor 38 arranged therein. Thus, the oxygen content of exhaust gases and / or intake air exiting each cylinder via the second exhaust valves 6 can be determined based on an output from the lambda sensor 38. In some embodiments, as shown in Fig. 1A, the intake duct 28 can include an electric compressor 60. The electric compressor 60 is arranged in a bypass duct 61, which is coupled to the intake duct 28 upstream and downstream of an electric compressor valve 63. In particular, an inlet to the bypass duct 61 is coupled to the intake duct 28 upstream of the electric compressor valve 63, and an outlet to the bypass duct 61 is coupled to the intake duct 28 downstream of the electric compressor valve 63 and upstream of it, where the first EGR duct 50 couples to the intake duct 28. Furthermore, the outlet of the bypass duct 61 is coupled upstream in the intake duct 28 from the turbocharger compressor 162. The electric compressor 60 can be electrically driven by an electric motor using energy stored in an energy storage device.In one example, the electric motor can be part of the electric compressor 60, as shown in Fig. 1A. When additional boost (e.g., increased intake air pressure above atmospheric pressure) is required, above the amount provided by the compressor 162, the controller 12 can activate the electric compressor 60 so that it rotates and increases the pressure of the intake air flowing through the bypass duct 61. The controller 12 can also actuate the electric compressor valve 63 to a closed or partially closed position to direct an increased amount of intake air through the bypass duct 61 and the electric compressor 60. The intake duct 28 can include one or more additional sensors (such as additional pressure, temperature, flow rate sensors and / or lambda probes). For example, as shown in Fig. 1A, the intake duct 28 includes a mass air flow (MAF) sensor 48, which is located upstream of the compressor 162, the electric compressor valve 63, and where the first EGR channel 59 couples to the intake duct 28. An intake pressure sensor 31 and an intake temperature sensor 33 are positioned in the intake duct 28 upstream of the compressor 162 and downstream of where the first EGR channel 50 couples to the intake duct 28. An intake lambda sensor 35 and an intake temperature sensor 43 may be located in the intake duct 28 downstream of the compressor 162 and upstream of the CAC 40. An additional intake pressure sensor 37 can be positioned in the intake duct 28 downstream of the CAC 40 and upstream of the throttle 28. In some embodiments, as shown in Fig. 1A, an additional intake lambda sensor 39 can be positioned in the intake duct 28 between the CAC 40 and the throttle 28.Furthermore, an intake manifold pressure (e.g. MAP) sensor 122 and an intake manifold temperature sensor 123 are positioned inside the intake manifold 44 upstream of all internal combustion engine cylinders. In some examples, the internal combustion engine 10 can be coupled to an electric motor / battery system (as shown in Fig. 1B) in a hybrid vehicle. The hybrid vehicle can have a parallel configuration, a series configuration, or a modification or combination thereof. Furthermore, in some embodiments, other internal combustion engine configurations can be used, for example, a diesel engine. The internal combustion engine 10 can be controlled, at least partially, by a control system 15, which includes the control unit 12, and by input from a driver via an input device (not shown in Fig. 1A). According to the illustration, the control system 15 receives information from a plurality of sensors 16 (various examples of which are described in this document) and sends control signals to a plurality of actuators 81. As an example, the sensors 16 can include pressure and temperature sensors and lambda sensors located within the intake manifold 28, intake manifold 44, exhaust manifold 74, and secondary exhaust manifold 80, as described above.Other sensors may include a throttle inlet pressure (TIP) sensor for estimating throttle inlet pressure (TIP) and / or a throttle inlet temperature sensor for estimating throttle air temperature (TCT), coupled downstream of the throttle in the intake manifold. Additional system sensors and actuators are described below with reference to FIG. 1B. As another example, the actuators 81 can include fuel injection devices, the valves 63, 42, 54, 59, 32, 97, 76, and the throttle 62. The actuators 81 can further include various camshaft timing actuators coupled to the cylinder intake and exhaust valves (as described below with reference to Fig. 1B). The controller 12 can receive input data from the various sensors, process the input data, and trigger the actuators in response to the processed input data based on the instruction or code programmed in a memory of the controller 12 according to one or more routines. Exemplary control routines (e.g., procedures) are described herein in Figs. 4A-15.For example, adjusting the EGR flow from the second exhaust manifold 80 to the intake port 28 may involve adjusting an actuator of the first EGR valve 54 to adjust the amount of exhaust gas flowing from the second exhaust manifold 80 to the intake port 28 upstream of the compressor 162. In another example, adjusting the EGR flow from the second exhaust manifold 80 to the intake port 28 may involve adjusting an actuator of an exhaust valve camshaft to adjust the opening timing of the second exhaust valves 6. In this way, the first and second exhaust manifolds from Fig. 1A can be designed to route the blow-off and scavenging portions of the exhaust gas separately. The first exhaust manifold 84 can route the blow-off pulse of the exhaust gas to the two-stage turbine 164 via the first manifold section 81 and the second manifold section 85, while the second exhaust manifold 80 can route the scavenging portion of the exhaust gas to the intake port 28 via one or more of the first EGR ports 50 and the second EGR ports 58 and / or to the exhaust port 74 downstream of the two-stage turbine 164 via the flow channel 98.For example, the first exhaust valves 8 direct the blow-off portion of the exhaust gases through the first exhaust manifold 84 to the two-stage turbine 164 and both the first and second emission control devices 70 and 72, while the second exhaust valves 6 direct the scavenging portion of the exhaust gases through the second exhaust manifold 80 and either to the intake manifold 28 via one or more EGR channels or to the exhaust manifold 74 and the second emission control device 72 via the flow channel 98. It should be noted that, while Fig. 1A shows the internal combustion engine 10 incorporating each of the first EGR channel 50, second EGR channel 58, flow channel 98, and flow channel 30, in alternative embodiments the internal combustion engine 10 may only include a section of these channels. For example, in one embodiment the internal combustion engine 10 may include only the first EGR channel 50 and flow channel 98, and not the second EGR channel 58 and flow channel 30. In another embodiment, the internal combustion engine 10 may include the first EGR channel 50, the second EGR channel 58, and flow channel 98, but not flow channel 30. In yet another embodiment, the internal combustion engine 10 may include the first EGR channel 50, flow channel 30, and flow channel 98, but not the second EGR channel 58. In some embodiments, the internal combustion engine 10 may not include the electric compressor 60.In further embodiments, the internal combustion engine 10 can include all or only some of the sensors shown in Fig. 1A. With reference to Fig. 1B, a partial view of a single cylinder of the internal combustion engine 10, which can be installed in a vehicle 100, is shown. Components already introduced in Fig. 1A are thus represented with the same reference numerals and are not introduced again. The internal combustion engine 10 is shown with the combustion chamber (cylinder) 130, the coolant sleeve 114, and the cylinder walls 132 with the piston 136 positioned therein and connected to the crankshaft 140. According to the illustration, the combustion chamber 130 communicates with the intake port 146 and the exhaust port 148 via a corresponding intake valve 152 and exhaust valve 156. As already described in Fig. 1A, each cylinder of the internal combustion engine 10 can discharge combustion products along two passages. In the illustrated view, the exhaust port 148 represents the first exhaust port (e.g., the exhaust port 148).opening) that leads from the cylinder to the turbine (such as the second exhaust pipe 86 from Fig. 1A), while the second exhaust pipe is not visible in this view. As already shown in Fig. 1A, each cylinder of the internal combustion engine 10 can contain two intake valves and two exhaust valves. In the illustrated view, the intake valve 152 and the exhaust valve 156 are located in an upper region of the combustion chamber 130. The intake valve 152 and the exhaust valve 156 can be controlled by the control unit 12 using appropriate cam actuation systems, including one or more cams. The cam actuation systems can use one or more cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT), and / or variable valve lift (VVL) systems to vary the valve operation. In the example shown, each inlet valve 152 is controlled by an inlet cam 151 and each exhaust valve 156 is controlled by an exhaust cam 153.The intake cam 151 can be actuated via an intake valve timing actuator 101, and the exhaust cam 153 can be actuated via an exhaust valve timing actuator 103 according to the set of intake and exhaust valve timing controls, respectively. In some examples, the intake and exhaust valves can be deactivated via the intake valve timing actuator 101 and the exhaust valve timing actuator 103, respectively. For example, the control unit can send a signal to the exhaust valve timing actuator 103 to deactivate the exhaust valve 156, so that it remains closed and does not open at its set timing. The position of the intake valve 152 and exhaust valve 156 can be determined by the valve position sensors 155 and 157, respectively. As introduced above, in one example, all exhaust valves of each cylinder can be controlled on the same exhaust camshaft.Thus, the timing of both the (second) scavenging exhaust valves and the (first) blow-off exhaust valves can be adjusted together via a single camshaft, but they can each have different timing relative to one another. In another example, the scavenging exhaust valve of each cylinder can be controlled on a first exhaust camshaft, and a blow-off exhaust valve of each cylinder can be controlled on a different, second exhaust camshaft. In this way, the valve timing of the scavenging valves and the blow-off valves can be adjusted separately. In alternative embodiments, the cam or valve timing control system(s) of the scavenging and / or blow-off exhaust valves can utilize a cam-in-cam system, an electro-hydraulic system on the scavenging valves, and / or an electromechanical valve lift control on the scavenging valves. For example, in some embodiments, the intake and / or exhaust valve can be controlled by an electric valve actuator. For example, cylinder 130 can alternatively include an intake valve controlled by an electric valve actuator and an exhaust valve controlled by a cam actuator, including CPS and / or VCT systems. In still other embodiments, the intake and exhaust valves can be controlled by a common valve actuator or actuator system, or by a variable valve timing actuator or actuator system. In one example, the intake cam 151 includes separate and distinct cam lobes that provide different valve profiles (e.g., valve timing, valve lift, duration, etc.) for each of the two intake valves of the combustion chamber 130. Similarly, the intake cam 153 can include separate and distinct cam lobes that provide different valve profiles (e.g., valve timing, valve lift, duration, etc.) for each of the two exhaust valves of the combustion chamber 130. In another example, the intake cam 151 can include a common lobe or similar lobes that provide a substantially similar valve profile for each of the two intake valves. Additionally, different cam profiles can be used for the various exhaust valves to separate exhaust gases released at low cylinder pressure from those released at exhaust pressure. For example, a first exhaust cam profile can open the first exhaust valve (e.g., blow-off valve) from the closed position shortly before bottom dead center (BDC) of the combustion chamber 130's power stroke and close the same exhaust valve long before top dead center (TDC) to selectively release blow-off gases from the combustion chamber. Furthermore, a second exhaust cam profile can be positioned to open a second exhaust valve (e.g., purge valve) from closed before a midpoint of the exhaust stroke and close it after TDC to selectively release the purge portion of the exhaust gases. Thus, the timing of the first and second exhaust valves can isolate cylinder blow-off gases from the scavenging portion of the exhaust gases, while remaining exhaust gases in the cylinder's dead space are cleaned by fresh intake air blow-through during the positive valve overlap between the intake valve and the scavenging exhaust valves. By directing a first portion of the exhaust gas leaving the cylinders (e.g., higher-pressure exhaust) to the turbine(s) and a higher-pressure exhaust port, and a later, second portion of the exhaust gas (e.g., lower-pressure exhaust) and blow-through air to the compressor inlet, the internal combustion engine system efficiency is improved. Turbine energy recovery can be increased, and internal combustion engine efficiency can be improved through increased exhaust gas recirculation (EGR) and reduced knocking. Further in Fig. 1B, the exhaust gas sensor 126 is shown coupled to the exhaust gas channel 148. The sensor 126 can be positioned in the exhaust gas channel upstream of one or more emission control devices, such as the devices 70 and 72 from Fig. 1A. The sensor 126 can be selected from various suitable sensors for providing an indication of an exhaust air-fuel ratio, such as a linear lambda sensor or UEGO sensor (Universal Exhaust Gas Oxygen Sensor; wide-band or wide-range lambda sensor), a dual-state lambda sensor or EGO sensor (as shown), a HEGO sensor (heated EGO sensor), a NOx, HC, or CO sensor. The downstream emission control devices can include one or more three-way catalysts (TWCs), NOx traps, BPFs, various other emission control devices, or combinations thereof. The exhaust gas temperature can be estimated by one or more temperature sensors (not shown) arranged in the exhaust duct 148. Alternatively, the exhaust gas temperature can be derived based on internal combustion engine operating conditions such as engine speed, load, air-fuel ratio (AFR), ignition retard, etc. The cylinder 130 can have a compression ratio, which is the volume ratio between the piston 136 at bottom dead center and at top dead center. Conventionally, the compression ratio is in the range of 9:1 to 10:1. However, in some cases where different fuels are used, the compression ratio may be higher. This can occur, for example, when using fuels with a higher octane rating or fuels with a higher latent heat of vaporization. The compression ratio may also be higher when using direct injection due to its effect on internal combustion engine knock. In some embodiments, each cylinder of the internal combustion engine 10 may include a spark plug 92 to initiate combustion. The ignition system 188 can provide a spark to the combustion chamber 130 via the spark plug 92 in response to a spark advance signal (SA) from the control unit 12 under selected operating modes. However, in some embodiments, the spark plug 92 may be omitted, for example, if the internal combustion engine 10 can initiate combustion by auto-ignition or by fuel injection, as may be the case with some diesel engines. In some embodiments, each cylinder of the internal combustion engine 10 can be equipped with one or more fuel injection devices to supply it with fuel. As a non-limiting example, cylinder 130 is shown with an injection valve 66. According to the illustration, a fuel injection device 66 is directly coupled to the combustion chamber 130 to inject fuel directly into it in proportion to the pulse width of a signal FPW received by the control unit 12 via the electronic driver 168. In this way, the fuel injection device 66 provides so-called direct injection (hereinafter also referred to as "DI") of fuel into the combustion cylinder 130. Although Fig. 1B shows the injection device 66 as a side-mounted injection device, it can also be arranged above the piston, for example, near the position of the spark plug 92.Such a position can improve mixing and combustion when the internal combustion engine is operated with an alcohol-based fuel, since some alcohol-based fuels have lower volatility. Alternatively, the injection device can be located above and near the intake valve to improve mixing. In an alternative embodiment, the injection device 66 can be a port fuel injection device that supplies fuel to the intake port upstream of the cylinder 130. Fuel can be supplied to the injector 66 via a high-pressure fuel system 180, which includes fuel tanks, fuel pumps, and a fuel distributor. Alternatively, fuel can be supplied at a lower pressure by a single-stage fuel pump, although in this case the timing of the direct fuel injection during the compression stroke may be more limited than when using a high-pressure fuel system. Furthermore, the fuel tanks, although not shown, can be equipped with a pressure converter that provides a signal to the control unit 12. The fuel tank in the fuel system 180 can contain fuel with different properties, for example, different fuel compositions.These differences can include varying alcohol contents, octane ratings, evaporation temperatures, fuel brands, and / or combinations thereof, etc. In some embodiments, the fuel system 180 can be coupled with a fuel vapor recovery system, which includes a canister for storing fuel for refueling and daily fuel vapors. The fuel vapors can be purged from the canister to the engine cylinders during internal combustion engine operation when purging conditions are met. For example, the purge vapors can be drawn naturally into the cylinder via the first intake port at or below atmospheric pressure. The internal combustion engine 10 can be controlled, at least partially, by the control unit 12 and by input from a driver 113 via an input device 118, such as an accelerator pedal 116. The input device 118 sends a pedal position signal to the control unit 12. The control unit 12 is depicted in Fig. 1B as a microcomputer, which includes a microprocessor unit 102, input / output ports 104, an electronic storage medium for executable programs and calibration values ​​(in this specific example, represented as read-only memory 106), direct access memory 108, keep-alive memory 110, and a data bus. The read-only memory 106 can be programmed with computer-readable data, which represents executable instructions for the microprocessor 102 to carry out the procedures and processes described below, as well as other variants that are anticipated but not specifically listed.The control unit 12 can receive various signals from sensors coupled to the internal combustion engine 10, in addition to the signals discussed above, including a measurement of the mass airflow (MAF) from mass airflow sensor 48; the engine coolant temperature (ECT) from temperature sensor 112, which is coupled to the cooling sleeve 114; a profile ignition pulse (PIP) signal from Hall effect sensor 120 (or other type), which is coupled to the crankshaft 140; the throttle position (TP) from a throttle position sensor; the manifold absolute pressure (MAP) signal from sensor 122; the cylinder AFR from EGO sensor 126; and abnormal combustion from a knock sensor and a crankshaft accelerometer. An engine speed signal, RPM, can be generated by the control unit 12 from the PIP signal.The manifold pressure signal MAP from a manifold pressure sensor can be used to provide an indication of vacuum or pressure in the intake manifold. Based on inputs from one or more of the aforementioned sensors, the controller 12 can adjust one or more actuators, such as the fuel injection device 66, the throttle 62, the spark plug 92, the intake / exhaust valves and cams, etc. The controller can receive input data from the various sensors, process the input data, and trigger the actuators in response to the processed input data based on instructions or codes programmed therein, according to one or more routines. In some examples, the vehicle 100 can be a hybrid vehicle with multiple torque sources available to one or more vehicle wheels 160. In other examples, the vehicle 100 can be a conventional vehicle with only one internal combustion engine or an electric vehicle with only one electric machine. In the example shown in Fig. 1B, the vehicle 100 includes an internal combustion engine 10 and an electric machine 161. The electric machine 161 can be a motor or a motor / generator and can therefore also be referred to as an electric motor. The crankshaft 140 of the internal combustion engine 10 and the electric machine 161 are connected to the vehicle wheels 160 via a transmission 167 when one or more clutches 166 are engaged.In the illustrated example, a first clutch 166 is provided between the crankshaft 140 and the electric machine 161, and a second clutch 166 is provided between the electric machine 161 and the transmission 167. The controller 12 can send a signal to an actuator of each clutch 166 to engage or disengage the clutch, thereby connecting or disconnecting the crankshaft 140 from the electric machine 161 and its associated components, and / or connecting or disconnecting the electric machine 161 from the transmission 167 and its associated components. The transmission 167 can be a manual transmission, a planetary gear system, or another type of transmission. The powertrain can be configured in various ways, including as a parallel, in-line, or in-line-parallel hybrid vehicle. The electric machine 161 draws electrical power from a traction battery 170 to provide torque to the vehicle wheels 160. The electric machine 161 can also be operated as a generator to provide electrical power for charging the battery 170, for example, during braking. With reference to Fig. 2A, a block diagram of a control system 200 for the air-fuel ratio of an internal combustion engine 10 and the air-fuel ratio flowing into an exhaust emission device is shown. At least sections of the system 200 can be contained in a system, as shown in Figs. 1A-1B, as executable instructions stored in non-volatile memory. Other sections of the system 200 can be actions performed via the controller 12, as shown in Figs. 1A-1B, to transmit states of devices or actuators in reality. The air-fuel control of the internal combustion engine described herein can operate in conjunction with sensors and actuators already described. A basic desired air-fuel ratio for the internal combustion engine is entered in block 202. Block 202 contains empirically determined air-fuel ratios for a multitude of engine speed and load pairs. In one example, the empirically determined air-fuel ratios are stored in a table in the control memory. The table can be accessed using existing engine speed and load values. The table outputs a desired air-fuel ratio for the internal combustion engine (e.g., 14.6:1) for the given engine speed and load. Block 202 outputs the desired air-fuel ratio for the internal combustion engine at summation point 204 and division point 203. The internal combustion engine's air mass flow rate, as determined by an air mass flow sensor or an intake manifold pressure sensor (such as the MAF 48 and / or MAP 122 shown in Figs. 1A-1B), is input to control system 200 at block 201. The internal combustion engine's air mass flow rate is divided by the desired air-fuel ratio of the internal combustion engine from block 202 at division point 203 to provide the desired fuel mass flow rate of the internal combustion engine. The fuel mass flow rate is output to multiplication point 208. At summing point 204, the actual air-fuel ratio of the internal combustion engine, as determined by lambda sensor 91, is subtracted from the desired air-fuel ratio to provide an air-fuel ratio error. Additionally, a deviation or offset value for the air-fuel ratio is added to both the desired and actual air-fuel ratios to improve catalyst efficiency. The air-fuel ratio deviation is output by summing point 248. Summing point 204 outputs an air-fuel ratio error to the proportional / integral control 206.The proportional / integral (PI) controller 206 integrates the error and applies proportional and integral gains to the air-fuel ratio error to output a fuel mass control correction or adjustment at the multiplication point 208. The desired internal combustion engine fuel mass flow rate from the division point 203 is multiplied by the fuel mass control correction at the multiplication point 208. The output of the multiplication point 208 is an adjusted fuel flow rate, which is converted at block 210 into a fuel injection device pulse width via a fuel injection device transfer function. Block 210 outputs a fuel pulse width to control the internal combustion engine's fuel injection devices (e.g., not shown in Fig. 2A, shown in Figs. 210).1A-1B as fuel injection devices 66) to drive, and the fuel injection devices of the internal combustion engine inject the adjusted fuel flow quantity or corrected fuel flow quantity into the internal combustion engine 10. The internal combustion engine 10 discharges exhaust gases to the turbocharger turbine (e.g., 163 / 165 from Fig. 1A). The exhaust gases pass through the turbocharger turbine 163 / 165 and into the emission control device 70. The emission control device 70 can be a three-way catalyst. The exhaust gases then pass from the emission control device 70 into the emission control device 72. The emission control device 72 can be a three-way catalyst, a particulate filter, an oxidation catalyst, or a combination of a catalyst and a particulate filter. Processed exhaust gases flow to the atmosphere after passing through the emission control device 72. As explained above, the turbocharger turbine 163 / 165, the emission control device 70, and the emission control device 72 can be part of an exhaust system of the internal combustion engine and can be positioned along an exhaust duct of the internal combustion engine. Exhaust gases from the internal combustion engine can be detected via the lambda sensor 91 to provide an actual air-fuel ratio for the engine. This actual air-fuel ratio can be used as feedback in the control system 200. The actual air-fuel ratio is input to the summing point 204. Exhaust gases downstream of the emission control device 70 and downstream of the emission control device 72 can be detected via the lambda sensor 90 to determine an air-fuel ratio within the exhaust system. The lambda sensor 90 is positioned in an exhaust duct extending between the emission control device 70 and the emission control device 72. Alternatively, exhaust gases can be detected via a lambda sensor positioned downstream of the emission control device 72 (e.g., the lambda sensor 93 shown in Fig. 1A) instead of the lambda sensor 90.The output from lambda sensor 90 or 93 is routed to switch 222, where it is then sent to summing point 248 or summing point 232 based on the state of switch 222, which is determined via the mode switching logic 224. The mode switching logic 224 determines an operating state of the internal combustion engine and can change the position or state of the switch 222 based on the operating mode of the internal combustion engine. In particular, the mode switching logic commands the switch 222 to its initial position when the airflow of the internal combustion engine falls below a threshold and when regeneration of the exhaust emission devices is not requested. The mode switching logic 224 also commands the valve 97 from Fig. 1A, which is positioned in the scavenging manifold bypass channel 98, to close via a first actuator reference function 226 when the airflow of the internal combustion engine falls below a threshold and when regeneration of the exhaust emission devices is not requested. The switch 222 is shown in its initial position. In its initial or first position, the switch 222 sends output data from the lambda sensor to the summing point 248. Air (e.g.,The blow-through) is not fed into the exhaust system (via the purge manifold bypass channel 98) when the switch 222 is in the first position. The mode switching logic 224 moves the switch 222 to a second position, as indicated by the arrow 250, as directed by the mode switching logic 224, when the internal combustion engine's airflow rate exceeds a threshold or when an exhaust emission device needs to be regenerated. In its second position, the switch 222 directs the output of the lambda sensor 90 to the summing point 232. The mode switching logic 224 opens the valve 97 via a control signal output from the first reference function 226 to the valve 97 when the internal combustion engine's airflow rate exceeds a threshold or when an exhaust emission device needs to be regenerated. The rate of airflow supplied to the exhaust system via the scavenging manifold bypass channel 98 is an open loop, which is adjusted via the second reference function 228.In one example, the second reference function 228 outputs a valve position command, an amount of intake and exhaust valve overlap (e.g., crankshaft angle duration where both intake and exhaust valves are open simultaneously), a boost pressure command, or another airflow adjustment command based on the internal combustion engine's air-fuel ratio and the mass flow rate of fuel and air being burned in the engine. For example, the internal combustion engine's air-fuel ratio and the mass flow rate of fuel and air being burned in the engine can be used to index a table or function that outputs a valve position command, an intake and exhaust valve overlap command, or a boost pressure command.The rate of airflow supplied to the exhaust system via the scavenging manifold is a closed loop controlled by the air-fuel ratio input to summing point 232. The valve opening amount, intake and exhaust valve overlap duration, boost pressure, or the actuation of other actuators that adjust the airflow through the scavenging manifold are adjusted at the internal combustion engine 10 according to the control adjustment output from summing point 236. Thus, the PI control 234 adjusts the airflow actuators of the internal combustion engine by modifying the output of the second reference function 228. Alternatively, the rate of airflow supplied to the exhaust system via the scavenging manifold can be an open loop controlled based on an estimate of the soot load stored in the emission control device 72, or a temperature estimate of the emission control device 72, instead of the lambda sensor output. The soot estimate can be based on a pressure differential across the emission control device 72 or other known internal combustion engine operating conditions. The temperature of the emission control device 72 can be estimated based on the internal combustion engine operating conditions, such as engine speed and load. Furthermore, the airflow rate can be a closed loop controlled based on the temperature of the emission control device 72 or a pressure differential across the emission control device 72.In such examples, the temperature or pressure difference for the lambda sensor input at summing point 232 is substituted, and the air-fuel reference is replaced by a temperature or pressure reference. The air flowing to the exhaust system did not participate in combustion in the internal combustion engine. In one example, the second reference function 228 outputs a control command to a variable valve timing actuator (e.g., 101 and 103 shown in Fig. 1B) to adjust the amount of valve opening overlap between an intake valve and a scavenging exhaust valve of the same cylinder, and thus the amount of blow-through air (e.g., a quantity of blow-through air) directed to the emission control device 72. Alternatively, the second reference function 228 outputs a control signal to a valve, such as valve 32 from Fig. 1A or valve 97 from Fig. 1A, each of which can adjust the airflow to the exhaust system and the emission control device 72.In addition, in some examples the second actuator reference function 228 outputs a control signal to a turbocharger wastegate actuator, which is used to adjust the boost pressure, which can also be used to adjust the airflow to the emission control device 72 by adjusting the blow-through air by increasing or decreasing the boost pressure. The timing of the air supply to the exhaust system from the scavenging manifold can be as follows: a stoichiometric or lean air-fuel ratio of the internal combustion engine is enriched to a rich or stoichiometric air-fuel ratio, and air supplied to the exhaust system is delivered to the downstream emission device 72 one engine cycle earlier, before exhaust gases produced from the rich or stoichiometric air-fuel ratio of the internal combustion engine reach the position of the downstream emission device 72. The air supply to the exhaust system can be terminated before the rich or stoichiometric air-fuel ratio of the internal combustion engine is leaned out. When switch 222 is in its second position, lambda sensor data from lambda sensor 90 or 93 is output to summing point 232 instead of summing point 248. The actual air-fuel ratio of the exhaust gas from lambda sensor 90 or 93 is subtracted from a desired air-fuel ratio of the exhaust gas provided by reference block 230. The desired air-fuel ratio output of the exhaust gas from reference block 230 may differ from the desired air-fuel ratio output of the internal combustion engine from block 202. In one example, the desired air-fuel ratio of the exhaust gas is determined empirically and stored in a table indexed by the internal combustion engine speed and load.The desired air-fuel ratio output of the exhaust gas from block 230 can be a stoichiometric air-fuel ratio when the internal combustion engine's air-fuel ratio is rich at high engine speeds and loads, with the engine's airflow exceeding the threshold. The desired air-fuel ratio output of the exhaust gas from block 230 can be a lean stoichiometric ratio when the exhaust emission device is requested to regenerate, while the internal combustion engine's air-fuel ratio is stoichiometric. Subtracting the actual air-fuel ratio of the exhaust gas from the desired air-fuel ratio of the exhaust gas provides an air-fuel ratio error of the internal combustion engine's exhaust gas, which is input to a second PI control 234.The air-fuel ratio error of the exhaust gas is processed by the PI control and a control correction is fed to summing point 236. The internal combustion engine speed (N) and load values ​​are used to index air-fuel deviation values ​​in Table 244. These air-fuel deviation values ​​are empirically determined and stored in the control memory. They provide an adjustment to the air-fuel mixtures in the exhaust system to improve catalyst efficiency. The air-fuel deviation and the air-fuel ratio in the exhaust system are added to the desired exhaust air-fuel ratio and the internal combustion engine output air-fuel ratio at summing point 204 when switch 222 is in its initial position. If switch 222 is not in its initial position, the output of summing point 248 can be adjusted to a predetermined value, such as zero. In a first example of how the control system 200 can operate, the control adjustment output from summing point 236 can be an adjustment of the amount of intake and exhaust valve overlap, causing air to pass through the internal combustion engine without participating in combustion. By increasing the intake and exhaust valve overlap, the airflow through the internal combustion engine and via the scavenging manifold bypass channel (e.g., 98 shown in Fig. 1A) into the exhaust system can be increased. Conversely, by decreasing the intake and exhaust valve overlap, the airflow through the internal combustion engine and via the scavenging manifold bypass channel into the exhaust system can be reduced. In a second example of how the control system 200 can operate, the control adjustment output from the summing point 236 can be an adjustment of the valve (e.g., 97 from Fig. 1A) positioned in the scavenging manifold bypass channel, or of a valve (e.g., 32 from Fig. 1A) positioned in a hot pipe (e.g., 30 from Fig. 1A). When the internal combustion engine 10 is operated at high loads using high boost pressure, the intake manifold pressure can be greater than the scavenging manifold pressure and the exhaust system pressure, allowing fresh air that has not participated in combustion to pass through the hot pipe to the scavenging manifold and into the exhaust system to lean out exhaust gases and provide oxygen to the emission control device 72. Alternatively, fresh air can pass through the internal combustion engine cylinders and into the scavenging manifold 80 without having participated in combustion.The air can then be directed via the purge manifold bypass channel 98 to the emission control device 72 to lean out the exhaust gases and provide oxygen to the emission control device 72. Air can be directed to the emission control device 72 in the same way in response to a request to regenerate the emission control device. In an example where the emission control device is a particulate filter, a request to regenerate the particulate filter can occur in response to a pressure drop at the particulate filter that exceeds a threshold pressure. In this way, the System 200 can control the air-fuel ratio of the internal combustion engine, as observed by lambda sensor 91, and the air-fuel ratio of the exhaust gas, as observed by lambda sensor 90 or 93, without introducing air into the exhaust system in a first mode. The System 200 can also control the air-fuel ratio of the internal combustion engine, as observed by lambda sensor 91, and the air-fuel ratio of the exhaust gas, as observed by lambda sensor 90 or 93, when air is introduced into the exhaust system via a scavenging manifold. The amount of air supplied to the exhaust system, which is not involved in combustion in the internal combustion engine, can be controlled by a closed-loop feedback system based on the output from lambda sensor 90 or 93 and adjustments of the valves coupled to a scavenging manifold, the intake and exhaust valve overlap, or the boost pressure. With reference to Fig. 2B, a block diagram of another embodiment of an internal combustion engine air-fuel ratio control system 250 and of an air-fuel ratio flowing into an exhaust emission device is shown. At least sections of the control system 250 can be included in a system, as shown in Figs. 1A-1B, as executable instructions stored in non-volatile memory. Other sections of the control system 250 can be actions performed via the controller 12, as shown in Figs. 1A-1B, to transmit states of devices or actuators in reality. The internal combustion engine air-fuel ratio control described herein can operate in conjunction with sensors and actuators already described. A basic desired air-fuel ratio for the internal combustion engine is entered in block 252. Block 252 contains empirically determined air-fuel ratios for a multitude of engine speed and load pairs. In one example, the empirically determined air-fuel ratios are stored in a table in the control memory. The table can be accessed using existing engine speed and load values. The table outputs a desired air-fuel ratio for the internal combustion engine (e.g., 14.6:1) for the given engine speed and load. Block 252 outputs the desired air-fuel ratio for the internal combustion engine at summation point 254 and division point 253. The air mass flow rate of the internal combustion engine, as determined by an air mass flow sensor or an intake manifold pressure sensor, is input to control system 250 at block 251. The air mass flow rate of the internal combustion engine is divided by the desired air-fuel ratio of the internal combustion engine from block 252 at division point 253 to provide the desired fuel mass flow rate of the internal combustion engine. The fuel mass flow rate is output to multiplication point 258. At summing point 254, the actual air-fuel ratio of the internal combustion engine, as determined by lambda sensor 91, is subtracted from the desired air-fuel ratio to provide an air-fuel ratio error. Additionally, a deviation or offset value for the air-fuel ratio is added to both the desired and actual air-fuel ratios to improve catalyst efficiency. This air-fuel ratio deviation is output by summing point 278. The summing junction 254 outputs an air-fuel ratio error to the proportional / integral control 256. The proportional / integral (PI) control 256 integrates the error and applies proportional and integral gains to the air-fuel ratio error to output a fuel mass control correction or adjustment to the multiplication junction 258. The desired internal combustion engine fuel mass flow rate from the division junction 253 is multiplied by the fuel mass control correction at the multiplication junction 258. The output of the multiplication junction 258 is further adjusted at the multiplication junction 259 in response to the output from the PI control 274. These adjustments compensate for the variation in the exhaust gas air-fuel ratio within the exhaust system, as determined by the lambda sensor 90 or 93. The output of the multiplication junction 259 (e.g.,(a fuel flow adaptation) is converted at block 260 into a fuel injection device pulse width via a fuel injection device transfer function. Block 260 outputs a fuel pulse width to drive fuel injection devices of the internal combustion engine (e.g., not shown in Fig. 2B, shown in Figs. 1A-1B as elements 66), and the fuel injection devices of the internal combustion engine inject the adapted fuel flow quantity or corrected fuel flow quantity into the internal combustion engine 10. The internal combustion engine 10 discharges exhaust gases to the turbocharger turbine (e.g., 163 / 165 from Fig. 1A). The exhaust gases pass through the turbocharger turbine 163 / 165 and into the emission control device 70. The emission control device 70 can be a three-way catalytic converter. The exhaust gases then pass from the emission control device 70 into the emission control device 72. The emission control device 72 can be a three-way catalytic converter, a particulate filter, an oxidation catalyst, or a combination of a catalyst and a particulate filter. Processed exhaust gases flow to the atmosphere after passing through the emission control device 72. Exhaust gases from the internal combustion engine can be detected via the lambda sensor 91 to provide an actual air-fuel ratio for the engine. This actual air-fuel ratio can be used as feedback in the control system 250. The actual air-fuel ratio is input to the summing point 254. Exhaust gases downstream of the emission control device 70 and downstream of the emission control device 72 can be detected via the lambda sensor 90 to determine an air-fuel ratio within the exhaust system. The lambda sensor 90 is positioned in an exhaust duct extending between the emission control device 70 and the emission control device 72. Alternatively, exhaust gases can be detected via a lambda sensor positioned downstream of the emission control device 72 (e.g., the lambda sensor 93 shown in Fig. 1A) instead of the lambda sensor 90.The output from lambda sensor 90 or 93 is routed to switch 262, where it is then sent to summing point 278 or summing point 272 based on the state of switch 262, which is determined via the mode switching logic 264. The mode switching logic 264 determines the operating state of the internal combustion engine and can change the position or state of the switch 262 based on the operating mode of the internal combustion engine. In particular, the mode switching logic commands the switch 262 to its initial position when the airflow of the internal combustion engine falls below a threshold and when regeneration of the exhaust emission devices is not requested. The mode switching logic 264 also commands the valve 97 from Fig. 1A, which is positioned in the scavenging manifold bypass channel 98, to close via a first actuator reference function 266 when the airflow of the internal combustion engine falls below a threshold and when regeneration of the exhaust emission devices is not requested. The switch 262 is shown in its initial position. In its initial or first position, the switch 262 sends output data from the lambda sensor to the summing point 278. The mode switching logic 264 moves the switch 262 to a second position, as indicated by arrow 150, as directed by the mode switching logic 264, when the internal combustion engine's airflow rate exceeds a threshold or when an exhaust emission device needs to be regenerated. In its second position, the switch 262 directs the output of lambda sensor 90 to the summing point 272. The mode switching logic 264 opens the valve 97 via a control signal output from the first reference function 266 to the valve 97 when the internal combustion engine's airflow rate exceeds a threshold or when an exhaust emission device needs to be regenerated. The rate of airflow supplied to the exhaust system via the scavenging manifold bypass channel 98 is an open loop, which is adjusted via the second reference function 268.In one example, the second reference function 268 outputs a valve position command, an amount of intake and exhaust valve overlap (e.g., crankshaft angle duration where both intake and exhaust valves are open simultaneously), a boost pressure command, or another airflow adjustment command based on the internal combustion engine's air-fuel ratio and the mass flow rate of fuel and air being burned in the engine. For example, the internal combustion engine's air-fuel ratio and the mass flow rate of fuel and air being burned in the engine can be used to index a table or function that outputs a valve position command, an intake and exhaust valve overlap command, or a boost pressure command. The mode switching logic 264 can also control the path by which air is directed to the exhaust system via the scavenging manifold bypass duct 98 in response to the output of the lambda sensor 91, which is positioned in the exhaust system upstream of the emission control device 70. For example, if the lambda sensor 91 is a first value (e.g., a first estimate of the air-fuel ratio), air can be supplied to the exhaust system at one point upstream of the emission control device 72 and downstream of the emission control device 70 via the internal combustion engine cylinders, the scavenging manifold, and the scavenging manifold bypass duct. The rate of air supplied to the exhaust system can be adjusted by modifying the valve timing. If the output of the lambda sensor 91 is a second value (e.g.,(A second estimate of the air-fuel ratio) allows air to be supplied to the exhaust system at a point upstream of the emission device 72 and downstream of the emission device 70 via the hot pipe 30, the scavenging manifold 80, and the scavenging manifold bypass pipe 98. The rate of air supplied to the exhaust system can be adjusted by adjusting the valve 32 and / or the valve 97. By selectively directing air that has not participated in combustion through different paths, it may be possible to supply air to the exhaust system over a wide range of internal combustion engine operating conditions, thus reducing internal combustion engine emissions. When switch 262 is in its second position, lambda sensor data from lambda sensor 90 or 93 is output to summing point 272 instead of summing point 278. The actual exhaust air-fuel ratio from lambda sensor 90 or 93 is subtracted from a desired exhaust air-fuel ratio provided by reference block 270. The desired exhaust air-fuel ratio output from reference block 270 may differ from the desired engine air-fuel ratio output from block 252. In one example, the desired exhaust air-fuel ratio is determined empirically and stored in a table indexed by engine speed and load.The desired air-fuel ratio output of the exhaust gas from block 270 can be a stoichiometric air-fuel ratio if the internal combustion engine's air-fuel ratio is rich at high engine speeds and loads. The desired air-fuel ratio output of the exhaust gas from block 270 can be a lean stoichiometric ratio if the exhaust emission device is requested to regenerate while the internal combustion engine's air-fuel ratio is stoichiometric. Subtracting the actual air-fuel ratio of the exhaust gas from the desired air-fuel ratio of the exhaust gas provides an air-fuel ratio error of the internal combustion engine's exhaust gas, which is input to a second PI control 274.The air-fuel ratio error of the exhaust gas is processed by the PI control 274, which integrates the air-fuel error and applies proportional and integral gains to the output of the summing junction 272, and a control correction is fed to the multiplication junction 259. The timing of the air supply to the exhaust system from the scavenging manifold can be as follows: a stoichiometric or lean air-fuel ratio of the internal combustion engine is enriched to a rich or stoichiometric air-fuel ratio, and air supplied to the exhaust system is delivered to the downstream emission device 72 one engine cycle earlier, before exhaust gases produced from the rich or stoichiometric air-fuel ratio of the internal combustion engine reach the position of the downstream emission device 72. The air supply to the exhaust system can be terminated before the rich or stoichiometric air-fuel ratio of the internal combustion engine is leaned out. The internal combustion engine speed (N) and load values ​​are used to index air-fuel deviation values ​​in Table 276. These air-fuel deviation values ​​are empirically determined and stored in the control memory. They provide an adjustment to the air-fuel mixtures in the exhaust system to improve catalyst efficiency. The air-fuel deviation and the air-fuel ratio in the exhaust system are added to the desired exhaust air-fuel ratio and the internal combustion engine output air-fuel ratio at summing point 254 when switch 262 is in its initial position. If switch 262 is not in its initial position, the output of summing point 278 can be adjusted to a predetermined value, such as zero. In this way, the System 250 can control the air-fuel ratio of the internal combustion engine, as observed by lambda sensor 91, and the air-fuel ratio of the exhaust gas, as observed by lambda sensor 90 or 93, without introducing air into the exhaust system in a first mode. The System 250 can also control the air-fuel ratio of the internal combustion engine, as observed by lambda sensor 91, and the air-fuel ratio of the exhaust gas, as observed by lambda sensor 90 or 93, when air is introduced into the exhaust system via a scavenging manifold. The amount of fuel delivered to the internal combustion engine can be a closed loop, adjusted in response to the amount of air supplied to the exhaust system that is not involved in combustion in the internal combustion engine.The fuel injected into the internal combustion engine can be adjusted based on the output from lambda sensor 90 or 93. As an example, one technical effect of directing air to an exhaust system, with an emission control device positioned above a scavenging manifold, where the air has not participated in combustion in an internal combustion engine, the scavenging manifold being in fluid communication with a cylinder's scavenging exhaust valve and an intake manifold, the cylinder including a blow-off exhaust valve in fluid communication with a blow-off manifold; and of adjusting an amount of fuel injected into the internal combustion engine in response to an output from a first lambda sensor, the first lambda sensor being positioned in the exhaust system upstream of the emission control device, is to more precisely control the air-fuel ratio of the exhaust gas downstream of the emission control device for more efficient internal combustion engine operation and reduced internal combustion engine emissions.As another example, the technical effect of directing air from an intake manifold through a plurality of internal combustion engine cylinders to a junction of an exhaust duct and a bypass duct in response to a condition, the junction being positioned along the exhaust duct between the first and second emission control devices; and allowing exhaust gas to flow to the first emission control device while the air flows to the junction, is to increase the amount of oxygen entering the second emission control device, thereby maintaining a stoichiometric mixture entering the second emission control device, and thus enhancing the function of the second emission control device and reducing internal combustion engine emissions.In another example, the increased oxygen content can help in the regeneration and burning of soot from the second emission control device, thus also leading to an increased function of the second emission control device and reduced emissions. Referring to Fig. 3A, Diagram 300 presents exemplary valve timings with respect to one piston position for an internal combustion engine cylinder comprising four valves: two intake valves and two exhaust valves, as described above with reference to Figs. 1A-1B. The example from Fig. 3A is drawn substantially to scale, although not every single point is labeled with numerical values. Thus, relative differences in timing can be estimated from the dimensions of the drawing. However, other relative timings may be used if appropriate. Further, in Fig. 3A, the cylinder is configured to receive intake air via two inlets and to discharge a first blow-off portion via a first exhaust valve (e.g., the first blow-off, or exhaust valves 8 shown in Fig. 1A) to a turbine inlet, a second purge portion via a second exhaust valve (e.g., the second purge, or exhaust valves 6 shown in Fig. 1A) to an intake port, and to discharge unburned blow-through air via the second exhaust valve to the intake port. By synchronizing the timing of the opening and / or closing of the second exhaust valve with that of the two intake valves, residual exhaust gases in the cylinder dead space can be cleaned and recirculated together with fresh intake blow-through air as EGR. Diagram 300 illustrates an internal combustion engine position along the x-axis in crank angle degrees (CAD). Diagram 302 depicts piston positions (along the y-axis) with respect to their position relative to top dead center (TDC) and / or bottom dead center (BDC), and further with respect to their position within the four strokes (intake, compression, power, and exhaust) of an internal combustion engine cycle. During the operation of an internal combustion engine, each cylinder typically undergoes a four-stroke cycle, comprising an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. During the intake stroke, the exhaust valves generally close and the intake valves open. Air is drawn into the cylinder through the appropriate intake port, and the piston moves toward the bottom of the cylinder to increase the volume. The position at which the piston is near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber has reached its maximum volume) is typically referred to by those skilled in the art as bottom dead center (BDC). During the compression stroke, both the intake and exhaust valves are closed. The piston moves toward the cylinder head to compress the air within the combustion chamber.The point at which the piston is closest to the cylinder head at the end of its stroke (e.g., when the combustion chamber has its smallest volume) is typically referred to by those skilled in the art as top dead center (TDC). In a process referred to herein as injection, fuel is introduced into the combustion chamber. In a process referred to herein as ignition, the injected fuel is ignited by known ignition devices, such as a spark plug, resulting in combustion. During the power stroke, the expanding gases push the piston back to bottom dead center (BDC). A crankshaft converts this piston motion into torque of the rotating shaft. During the exhaust stroke, the exhaust valves open in a conventional design to release the remaining burnt air-fuel mixture into the appropriate exhaust ports, and the piston returns to TDC.In this description, the second exhaust (purge) valves can be opened after the start of the exhaust stroke and remain open after the end of the exhaust stroke, while the first exhaust (blow-off) valves remain closed and the intake valves are opened to purge residual exhaust gases with blow-through air. The curve 304 represents a first intake valve timing, lift and duration for a first intake valve (Int_1), while the curve 306 represents a second intake valve timing, lift and duration for a second intake valve (INT_2) that is coupled to the intake port of the internal combustion engine cylinder. The curve 308 represents an exemplary exhaust valve timing, lift, and duration for a first exhaust valve (Exh_1, which may correspond to the first, or blow-off, exhaust valves 8 shown in Fig. 1A) coupled to a first exhaust manifold (e.g., the blow-off exhaust manifold 84 shown in Fig. 1A) of the internal combustion engine cylinder, while the curve 310 represents an exemplary exhaust valve timing, lift, and duration for a second exhaust valve (Exh_2, which may correspond to the second, or purge, exhaust valves 6 shown in Fig. 1A) coupled to a second exhaust manifold (e.g., the blow-off exhaust manifold 84 shown in Fig. 1A).Figure 1A shows the scavenging manifold (80) of the internal combustion engine cylinder coupled to the exhaust manifold. As already explained, the first exhaust manifold connects a first exhaust valve to the inlet of a turbine in a turbocharger, and the second exhaust manifold connects a second exhaust valve to an intake port via an EGR channel. The first and second exhaust manifolds can be separated from each other, as explained above. In the example shown, the first and second intake valves are fully opened from a closed position under a common timing control (trajectories 304 and 306), starting close to intake stroke TDC, shortly after CAD2 (e.g., at or shortly after intake stroke TDC), and closing after a subsequent compression stroke has begun after CAD3 (e.g., after bottom dead center). Additionally, when fully open, the two intake valves can be opened with the same amount of valve lift L1 for the same duration D1. In other examples, the two valves can be operated with a different timing control by adjusting the phase, lift, or duration based on the internal combustion engine conditions. Moving on to the exhaust valves, the timing of the first and second exhaust valves is staggered relative to each other. Specifically, the first exhaust valve opens from a closed position during the first timing event (progression 308), which occurs earlier in the internal combustion engine than the timing event (progression 310) that opens the second exhaust valve from closed. In particular, the first timing event for opening the first exhaust valve occurs between top dead center (TDC) and bottom dead center (BDC) of the power stroke before CAD1 (e.g., before the exhaust stroke BDC), while the timing event for opening the second exhaust valve occurs shortly after the exhaust stroke BDC, after CAD1 but before CAD2. The first exhaust valve (progression 308) closes before the end of the exhaust stroke, and the second exhaust valve (progression 310) closes after the end of the exhaust stroke.Thus, the second exhaust valve remains open to somewhat overlap with the opening of the intake valves. To execute this, the first exhaust valve can be fully opened from the closed position before the start of an exhaust stroke (e.g., between 90 and 40 degrees before bottom dead center), remain fully open during the first part of the exhaust stroke, and remain fully closed before the exhaust stroke ends (e.g., between 50 and 0 degrees before top dead center) to capture the blow-off portion of the exhaust pulse. The second exhaust valve (flow 310) can be fully opened from a closed position shortly after the start of the exhaust stroke (e.g., between 40 and 90 degrees after bottom dead center), remain open during the second part of the exhaust stroke, and close completely after the intake stroke begins (e.g., between 20 and 70 degrees after top dead center) to release the scavenging portion of the exhaust gas. Additionally, the second exhaust valve and the intake valves can, as shown in Fig. 3A, have a positive overlap phase (e.g.,The valves must be open between 20 degrees before top dead center (TDC) and 40 degrees after TDC, and between 40 and 90 degrees after TDC, to allow EGR (exhaust gas recirculation) flow. This cycle, during which all four valves are operational, can repeat itself based on the operating conditions of the internal combustion engine. Additionally, the first exhaust valve can be opened with a first amount of valve lift L2 during a first timing control, while the second exhaust valve can be opened with a second amount of valve lift L3 (progression 310), where L3 is less than L2. Furthermore, the first exhaust valve can be opened for a duration D2 during the first timing control, while the second exhaust valve can be opened for a duration D3, where D3 is less than D2. It should be noted that in alternative embodiments, the two exhaust valves can have the same amount of valve lift and / or the same opening duration, while opening occurs at differently staggered timing controls. In this way, internal combustion engine efficiency and power can be increased using staggered valve timing by separating exhaust gases released at higher pressure (e.g., expansion of blow-off exhaust gases in a cylinder) from residual exhaust gases at lower pressure (e.g., exhaust gases remaining in the cylinder after blow-off) into the various channels. By transporting residual low-pressure gases as EGR along with blow-off air to the compressor inlet (via the EGR channel and the secondary exhaust manifold), combustion chamber temperatures can be reduced, thereby mitigating knocking and retardation from maximum torque. Since the exhaust gases are routed at the end of the stroke either downstream of a turbine or upstream of a compressor, both of which have lower pressures, exhaust pumping losses can be minimized to improve internal combustion engine efficiency. This allows exhaust gases to be used more efficiently than simply routing all the exhaust from one cylinder through a single common exhaust port to a turbocharger turbine. Several advantages can be achieved. For example, the average exhaust pressure supplied to the turbocharger can be increased by separating the blow-off pulse and directing it to the turbine inlet to improve turbocharger output. Additionally, fuel efficiency can be improved because blow-off air is not routed to the catalytic converter but instead to the compressor inlet, thus preventing excess fuel from being injected into the exhaust gases to maintain a stoichiometric ratio. Fig. 3A can represent initial settings for the intake and exhaust valve timing of the internal combustion engine system. Under different engine operating modes, the intake and exhaust valve timing can be adjusted based on these initial settings. Fig. 3B shows exemplary adjustments to the valve timing of the blowdown exhaust valve (BDV), scavenge valve (SV), and intake valve (IV) for a representative cylinder under various engine operating modes. In particular, Diagram 320 illustrates an engine position along the x-axis in crank angle degrees (CAD).Diagram 320 also illustrates changes in the timing of the BDV, IV, and SV of each cylinder for an output blow-through combustion cooling (BTCC) mode with higher EGR at curve 322, an output BTCC mode with lower EGR at curve 324, a first cold start mode (A) at curve 326, a second cold start mode (B) at curve 328, a fuel cut-off switch-off (DFSO) mode at curve 330, a BTCC mode in an internal combustion engine system without a scavenging manifold bypass channel (e.g., channel 98 shown in Fig. 1A), an early intake valve closing (EIVC) mode at curve 334, and a compressor threshold mode at curve 336. In the examples shown in Fig. 3B, it is assumed that the SVs and BDVs move together (e.g., via a common cam of a cam timing system).In this way, although the SVs and BDVs open and close relative to each other at different times, they can be adjusted together by the same amount (e.g., advanced or delayed). However, in alternative embodiments, the BDVs and SVs can be controlled separately and thus be adjustable independently of each other. During the initial BTCC mode with higher EGR, as shown in graph 322, the valve timing controls can be in their initial settings. The SV and BDV are at full advance (e.g., as advanced as the valve timing hardware allows). In this mode, intake airflow through the SV can be increased by retarding the SV and / or advancing the IV (increasing IV and SV overlap and thus airflow). Retarding the BDV and SV reduces EGR, as shown in graph 324 in the initial BTCC mode with lower EGR. As seen in graph 326, the SV can be adjusted to an early opening / lift profile during the first cold start mode (A). During a second cold start mode (B), as shown in graph 328, the SV can be disabled so that it does not open. Additionally, the IV can be advanced while the BDV is retarded, thereby increasing combustion stability. During DFSO mode, the BDV can be deactivated in curve 330 (e.g., so that it remains closed and does not open at its set timing). The IV and SV timings can maintain their initial positions, or the SV can be delayed to increase the overlap between the SV and the IV, as shown in curve 330. As a result, all combusted exhaust gases are routed through the SV to the scavenge exhaust manifold and back to the intake manifold. Curve 334 shows the EIVC mode, where the IV is deactivated and the exhaust cam is staggered for maximum delay. Thus, the SV and BDV are delayed together. As described below with reference to Fig. 7A, this mode allows air to be drawn into the internal combustion engine cylinder via the SV and discharged through the BDV. Curve 336 shows an example of valve timing for a compressor threshold mode.In this mode, the intake cam of the IV is advanced and the exhaust cam of the SV and BDV is retarded to reduce EGR and the exhaust gas flow to the compressor inlet. Further details of these operating modes are discussed below with reference to Fig. 4A-15. With reference to Figures 4A-4B, a flowchart of a method 400 for operating a vehicle incorporating a split exhaust combustion engine system (such as the system shown in Figures 1A-1B) is shown, wherein a second exhaust manifold (e.g., the scavenging manifold 80 shown in Figure 1A) directs exhaust gas and blow-through air to an inlet of the combustion engine system, and a first exhaust manifold (e.g., the blow-off manifold 84 shown in Figure 1A) directs exhaust gas to an outlet of the combustion engine system under various vehicle and combustion engine operating modes. Instructions for carrying out method 400 and the other methods described herein can be issued by a controller (such as the controller 12 shown in Figures 1A-1B) based on instructions stored in a memory of the controller and in conjunction with sensors of the combustion engine system, such as those described above in connection with Figures 1A-1B.The controls can execute the received signals from the sensors described in sections 1A-1B. The control unit can utilize internal combustion engine actuators of the internal combustion engine system to adjust the internal combustion engine operation according to the procedures described below. For example, the control unit can actuate various valve actuators on different valves to move the valves to the commanded positions and / or actuate various valve timing actuators on different cylinder valves to adjust the timing of the cylinder valves. Method 400 begins at 402 with estimating and / or measuring the vehicle and internal combustion engine operating conditions. Internal combustion engine operating conditions may include brake pedal position, accelerator pedal position, operator torque requirement, battery charge status (in a hybrid electric vehicle), ambient temperature and humidity, atmospheric pressure, internal combustion engine speed, internal combustion engine load, the amount of input into a transmission of a vehicle in which the internal combustion engine is installed, from an electric machine (e.g., the one shown in Fig.1B shown electric machine 161) or crankshaft of the internal combustion engine, internal combustion engine temperature, mass airflow (MAF), manifold absolute pressure (MAP), oxygen content of intake air / exhaust gases at various points in the internal combustion engine system, timing of the cylinder intake and exhaust valves, positions of various valves of the internal combustion engine system, temperature and / or load level of one or more emission control devices, pressures in the exhaust manifolds, exhaust pipes, exhaust port and / or intake port, quantity of fuel injected into the internal combustion engine cylinders, operating state of an electric compressor (e.g. the electric compressor 60 shown in Fig. 1A), speed of the turbocharger, condensation on the turbocharger compressor, temperature at the turbocharger compressor inlet and / or outlet, etc. In document 403, the procedure involves determining whether the vehicle is operating in an electric mode. As explained above, in one embodiment the vehicle may be a hybrid electric vehicle. A vehicle operating mode can be determined based on the estimated operating conditions. For example, based on at least the estimated driver torque requirement and the battery charge status, it can be determined whether the vehicle is to operate in an internal combustion engine-only mode (where the internal combustion engine drives the vehicle's wheels), an assist mode (where the battery assists the internal combustion engine when driving the vehicle), or an electric-only mode (where only the battery drives the vehicle via an electric motor or generator).In one example, if the requested torque can only be provided by the battery, the vehicle can be operated in all-electric mode, driven solely by engine torque. In another example, if the requested torque cannot be provided by the battery, the vehicle can be operated in internal combustion engine mode or in support mode, driven by at least some internal combustion engine torque. The vehicle can be operated accordingly in the specified operating mode. If, at 403, it is confirmed that the vehicle is operating in all-electric mode, the procedure proceeds to 405 to operate in all-electric mode (e.g., electric), which involves driving the hybrid vehicle solely by engine torque (and not internal combustion engine torque). Details of operation in electric mode are explained below with reference to Fig. 14.Alternatively, if the vehicle is not operating in electric mode or is not a hybrid vehicle, the vehicle can be driven by at least some (or all) of the internal combustion engine torque and proceed to 404. In 404, the procedure involves determining whether cold-start conditions are met. In one example, a cold-start condition might involve the internal combustion engine operating at an engine temperature below a threshold temperature. In another example, the engine temperature might be a coolant temperature. In another example, the engine temperature might be the temperature of a catalyst (e.g., an emissions control device, such as one of the emissions control devices 70 and 72 shown in Fig. 1A) positioned in the exhaust duct. If the internal combustion engine is operating under the cold-start condition, the procedure proceeds to 406 to operate in a cold-start mode.Details regarding operation in cold start mode are explained below with reference to Fig. 5. Otherwise, if cold-start conditions are not met (e.g., internal engine temperatures exceed specified thresholds), the procedure proceeds to 408. In 408, the procedure involves determining whether a fuel cut-off shutdown (DFSO) event occurs (or whether the vehicle slows down). As an example, a DFSO event may be initiated and / or indicated when an operator releases the vehicle's accelerator pedal and / or presses a brake pedal. In another example, a DFSO event may be indicated when the vehicle speed decreases by a threshold amount. The DFSO event may involve terminating fuel injection into the internal engine cylinders. When the DFSO event occurs, the procedure proceeds to 410 to operate in DFSO mode. Details of operating in DFSO mode are explained below with reference to Figure 6. If DFSO conditions are not met or DFSO does not occur, the procedure proceeds to 412. In 412, the procedure involves determining whether the internal combustion engine load falls below a threshold load. In one example, the threshold load may fall below a lower threshold load at which a gas reaction state occurs (e.g., when an intake throttle, such as throttle 62 shown in Fig. 1A, is at least partially closed so that it is not fully open) and / or at which an internal combustion engine idling state occurs (e.g., when the internal combustion engine is idling). In some examples, the threshold load may be based on a load and / or throttle opening at which backflow through the EGR channel (e.g., channel 50 shown in Fig. 1A) and the scavenging exhaust manifold may occur. The return flow may include intake air that flows from the intake manifold through the EGR channel and the purge exhaust manifold and through the purge exhaust valves into the internal combustion engine cylinders.If the internal combustion engine load falls below the threshold load (or the throttle is not fully open and thus at least partially closed), the procedure switches to 414 to operate in a gas reaction mode. Details of operation in gas reaction mode are discussed below with reference to Figures 7A-7B. If the internal combustion engine load does not fall below the threshold load at 412, the procedure proceeds to 416. At 416, the procedure involves determining whether an electric compressor is operating in the internal combustion engine system. In one example, the electric compressor may be an electric compressor positioned in the intake manifold upstream of where the EGR channel (which is coupled to the scavenging manifold) couples to the intake manifold, and upstream of the turbocharger compressor (such as the electric compressor 60 shown in Fig. 1A). As an example, the control may determine that the electric compressor is operating when it is electrically driven by energy stored in an energy storage device (such as a battery).For example, an electric motor (coupled to the energy storage device) can drive the electric compressor, and thus, when the electric motor is operating and driving the electric compressor, the controller can determine that the electric compressor is operating. The electric compressor can be switched on and driven by the motor and the stored energy in response to a request for additional boost (e.g., a pressure quantity above that provided by the turbocharger compressor alone at a given turbocharger speed). When the electric compressor is driven and thus operated by the electric motor of the electric compressor at 416, the method proceeds to 418 to operate in electric boost mode. Details of operation in electric boost mode are explained below with reference to Fig. 8. If the electric compressor is not operating (e.g., not driven by an electric motor coupled to the electric compressor), the method proceeds to 420. In 420, the method involves determining whether the compressor (e.g., the turbocharger compressor 162 shown in Fig. 1A) is operating at a threshold value. The operating threshold value (e.g., the limit) of the compressor may be one or more of the following: a compressor inlet temperature below a first threshold temperature (which may indicate condensation at the compressor inlet), a compressor outlet temperature above a second threshold temperature (temperatures at or above this second threshold temperature may lead to compressor deterioration), and / or a compressor rotational speed (e.g.,Compressor speed (which is also the turbocharger speed) exceeding a threshold speed (where speeds above this threshold can lead to compressor degradation). If the compressor operates above these operating thresholds, compressor degradation and / or reduced performance may occur. In another example, the procedure at 420 may additionally or alternatively include determining whether the internal combustion engine speed (RPM) or internal combustion engine load exceeds the relevant thresholds. For example, the internal combustion engine speed and / or load thresholds may correlate with compressor operation, such that if the internal combustion engine is operating at these engine speed or load thresholds, the compressor may reach one or more of the operating thresholds described above.Thus, at relatively high internal combustion engine power, speed, and / or load, the compressor can reach one or more of the operating thresholds. When the compressor is at or above one of the operating thresholds, or when the internal combustion engine speed and / or load are at their corresponding upper thresholds, the method switches to 421 to operate in compressor threshold mode (which may also be referred to herein as high-performance mode). Details of operation in compressor threshold mode are explained below with reference to Fig. 9. If the compressor is not operating at one of the operating thresholds (or if the internal combustion engine speed and / or load fall below their upper thresholds), the procedure proceeds to 422. At 422, the procedure involves determining whether a low-RPM transition pedal actuation condition exists. As an example, the low-RPM pedal actuation condition might involve when there is an increase in torque demand above a threshold torque demand when the internal combustion engine speed falls below a threshold speed. For instance, if a pedal position signal from an accelerator pedal exceeds a threshold (indicating that the accelerator pedal has been depressed by a threshold amount, thus indicating a requested increase in the internal combustion engine torque output), while the internal combustion engine speed remains below the threshold speed, the control system might determine that a low-RPM transition pedal actuation condition exists.When it is determined that the conditions for low-RPM transition pedal actuation are met, the method proceeds to 423 to reduce the amount of opening of the BTCC valve (e.g., valve 54 shown in Fig. 1A) to increase the scavenge manifold pressure to a desired level, the desired level being based on the intake manifold pressure (MAP) and the variable cam timing (VCT) of the intake and exhaust valves. For example, the method at 423 may include the control that determines the desired scavenge manifold pressure based on an estimated or measured MAP and the current timings (e.g., opening and closing timings) of the intake and exhaust (e.g., purge and blow-off) valves. For example, when the BTCC valve is fully open, the scavenge manifold operates close to the compressor inlet pressure (e.g., ambient pressure).In this mode, EGR and blow-off are higher, resulting in increased engine efficiency but a reserve throttling with a small excess. Increasing the desired (e.g., target) scavenge manifold pressure closer to MAP can reduce EGR and blow-off, allowing more charge air to be trapped in the cylinders. Thus, the BTCC valve can be modulated using scavenge manifold pressure feedback to achieve the desired level of EGR. For example, the target scavenge manifold pressure for a given output torque level can be mapped (e.g., in a table or chart stored in the control unit's memory) relative to the intake / exhaust valve VCT. In this way, the control unit can use a stored relationship between the scavenge manifold pressure and the intake / exhaust valve VCT. As an example, the controller can use a first lookup table stored in memory to determine the desired scavenge manifold pressure with MAP and the intake and exhaust valve timing controls as inputs and the desired scavenge manifold pressure as output. The controller can then use a second lookup table with the determined desired scavenge manifold pressure as input and one or more of a desired BTCC valve position, a duration for the BTCC valve to be fully closed, or an amount by which the BTCC valve to be reduced from the output to determine the commanded BTCC valve position. The controller can then send a signal to an actuator of the BTCC valve to move the BTCC valve to the desired position (e.g., fully closed or partially closed) and leave the BTCC valve in that position for the specified duration. As another example, the controller can use a logical determination (e.g.,(with regard to the position of the BTCC valve) based on logical rules that are a function of MAP, intake valve timing, and exhaust valve timing. The controller can then generate a control signal that is sent to the actuator of the BTCC valve. In some embodiments, the method may involve closing the BTCC valve at 423 until the desired purge manifold pressure is reached, and then reopening the BTCC valve. In another example, the method may involve modulating the BTCC valve at 423 between the open and closed positions to maintain the purge manifold pressure at the desired pressure.The purge manifold pressure can be measured by one or more pressure sensors positioned in the purge manifold or in the purge exhaust ports. The measured purge manifold pressure can then be used by the controller as feedback to further adjust the BTCC valve position to maintain the desired purge manifold pressure. In some examples, the controller may use a different lookup table with the measured purge manifold pressure and the desired purge manifold pressures as inputs and an adjusted BTCC valve position as output. If no low-RPM transition pedal actuation state exists at 422, the procedure proceeds instead to 424 in Fig. 4B. At 424, the procedure involves determining whether an internal combustion engine shutdown is expected or requested. The internal combustion engine shutdown may involve an ignition key off shutdown (e.g., when the vehicle is placed in Park and an operator turns off the internal combustion engine) or a start / stop shutdown (e.g., when the vehicle is stopped but not parked and the internal combustion engine automatically shuts off for a threshold duration in response to the stop). Thus, in an example, the controller may determine that a shutdown is requested in response to receiving an ignition key off signal from the vehicle's ignition and / or the vehicle being stopped for a threshold duration.When a shutdown request is received at the controller, the procedure switches to 426 to operate in a shutdown mode. Details of operation in shutdown mode are explained below with reference to Fig. 15. If a shutdown request is not received at 424, the procedure proceeds to 428. At 428, the procedure involves determining whether blow-through combustion cooling (BTCC) and EGR to the intake manifold via the scavenging exhaust manifold (e.g., via scavenging manifold 80 and the first EGR channel 50, as shown in Fig. 1A) are desired or currently enabled. For example, if the internal combustion engine load exceeds a second threshold load (e.g., higher than the threshold load at 412), blow-through and EGR to the intake manifold may be desired or enabled. In another example, if the internal combustion engine's BTCC hardware (e.g., the BTCC valve 54 and / or the scavenging exhaust valves 6, as shown in Fig. 1A) is enabled, blow-through and EGR may be enabled. For example, it can be determined that the BTCC hardware is activated if the purge outlet valves are operating (e.g., not deactivated) and the BTCC valve is open or at least partially open.If forced air flow and EGR are desired and / or the BTCC hardware is already enabled, the procedure switches to step 430 to operate in the initial BTCC mode. Details of operation in the initial BTCC mode are described below with reference to Figures 10-13. At 428, if BTCC is not desired, the procedure alternatively proceeds to 432 to deactivate the scavenging exhaust valves and operate the internal combustion engine without blow-through. For example, this may involve keeping the scavenging exhaust valves in the closed position and directing exhaust gases from the internal combustion engine cylinders only to the exhaust port via the blow-off exhaust valves. As an example, the control may send a deactivation signal to the valve actuators of the scavenging valves (e.g., exhaust valve timing actuator 103 shown in Fig. 1A) to deactivate the SVs of each cylinder. Furthermore, at 431, the procedure may involve not operating the internal combustion engine with EGR. The procedure then proceeds to 434 to keep the charge motion control valves (e.g., CMCVs 24 shown in Fig. 1A) in the open position so that no intake air is blocked as it enters the internal combustion engine cylinders via the intake ports. Then the process ends.Further on, Fig. 5 shows a method 500 for operating the internal combustion engine system in a cold-start mode. Method 500 can proceed from step 406 of method 400 as described above. Method 500 begins at step 502 by determining whether the purge outlet valves (e.g., the second outlet valves 6 shown in Fig. 1A) are activated by default. The purge outlet valves (SVs) can be activated by default (e.g., opened) if the valve actuation mechanism (e.g., various valve lift and / or VCT mechanisms, as described above and shown as the outlet valve timing actuator 103 in Fig. 1B) of the purge outlet valves is activated, such that the purge outlet valves are actuated to open at their set timing.In some examples, the valve actuation mechanism can be disabled so that the purge outlet valves do not open (and instead remain closed) at their set timing during the internal combustion engine cycle. The default setting can be the on state of the purge outlet valves when the internal combustion engine is shut down. In this way, the purge outlet valves can be either enabled or disabled by default when the internal combustion engine is started and during the cold start. If the purge outlet valves are enabled by default, the procedure proceeds to 504 to open the BTCC valve (e.g., valve 54 shown in Fig. 1A) for the initial start (e.g., the first rotation of the crankshaft). In the case of the 506, the procedure involves, after ignition of the first cylinder (e.g., after injection of fuel into the first cylinder and combustion of the air and fuel within the first cylinder), modulating the position of the BTCC valve to control the EGR through the EGR channel (e.g., channel 50 shown in Fig. 1A) and to the compressor inlet at a desired EGR flow rate. The desired EGR flow rate can be set based on the internal combustion engine operating conditions (e.g., engine load, MAF, combustion A / F, and / or set emission thresholds). In one example, modulating the position of the BTCC valve can involve switching the position of the BTCC valve between a fully open and a fully closed position to maintain a desired EGR flow rate to the intake port upstream of the compressor.In an alternative example, where the BTCC valve is a continuously variable valve adjustable to more than two positions, modulating the position of the BTCC valve can involve continuously adjusting its position to a variety of positions between fully open and fully closed to maintain the desired EGR flow rate. Furthermore, the method can involve adjusting the position of the BTCC valve to prevent backflow through the EGR channel (e.g., intake air flow from the intake port through the EGR channel to the purge exhaust manifold). For example, in response to a purge exhaust manifold pressure (e.g., the pressure of the second exhaust manifold 80 shown in Fig. 1A) falling below atmospheric pressure, the control system can actuate the BTCC valve to the fully closed position to block flow through the EGR channel.Thus, in some examples, the procedure at 506 may involve the controller making a logical determination (e.g., regarding the position of the BTCC valve) based on logical rules that are a function of the desired EGR flow and a pressure in the purge outlet valve. As another example, the controller may include a lookup table stored in memory with the desired EGR flow and purge manifold pressure as inputs and the BTCC valve position as output. The controller may then generate a control signal that is sent to an actuator of the BTCC valve, causing the BTCC valve to adjust (e.g., by adjusting a valve plate of the BTCC valve) to the determined position. If the BTCC valve at 506 is closed, the procedure may further involve opening (or at least partially opening) the purge manifold bypass valve (e.g.,in an internal combustion engine system that includes a scavenging manifold bypass channel, such as channel 98 and SMBV 97, as shown in Fig. 1A). In this way, excess pressure in the scavenging exhaust manifold can be released by allowing at least some of the exhaust gases discharged from the scavenging outlet valves to flow to the scavenging exhaust manifold and then, via the scavenging manifold bypass channel, to the exhaust manifold. In 508, the method involves determining whether it is possible to adjust the activation state of the purge outlet valves. As an example, the VCT systems may include hydraulically controlled valves that rely on oil pressure to operate and to change an activation state and / or timing profile of the valves. Thus, in some examples, the activation state of the purge outlet valves can only be changed when the oil pressure reaches a threshold pressure for changing a timing profile or activation state of the purge outlet valves. In alternative embodiments, the purge outlet valves can be adjusted in response to another variable. If, in 508, it is determined that the activation state or timing profile of the purge outlet valves cannot be adjusted, the method proceeds to 510 to leave the purge outlet valves activated and to continue modulating the BTCC valve.However, if the on / off state of the purge outlet valves can be changed, the procedure proceeds to 512 to determine whether the purge outlet valves are capable of switching between timing profiles. In one example, the purge outlet valves can be switched between cam timing profiles (e.g., to adjust the timing for opening and closing within the internal combustion engine cycle) rather than being deactivated. If the purge outlet valves cannot be switched between timing profiles, the procedure proceeds to 514 to deactivate the purge outlet valves (e.g., to disable the actuating / timing mechanisms of the purge outlet valves so that the purge outlet valves can remain closed and do not open at their intended timing) and to close the BTCC valve (e.g., to close it completely).In some examples, the procedure at 514 may involve retaining some hydrocarbon emissions during cranking within the purge exhaust manifold until the BTCC valve can be reopened. Adjusting the purge exhaust valves and the BTCC valve in this way while the internal combustion engine warms up can increase the low-load stability of the engine while reducing emissions during cold starts. If the purge outlet valves can be switched between timing profiles, the procedure at 512 can alternatively proceed to 516. At 516, the procedure involves switching the timing of the purge outlet valves to an early opening / lift profile (as shown in trace 326 from Fig. 3B, as described above) and closing the BTCC valve. In one example, the procedure at 516 can involve advancing the timing (e.g., the opening timing) of the purge outlet valves and / or increasing an amount of the lift of the purge outlet valves by switching the cam timing profile. In some examples, the procedure at 516 can further involve opening the purge manifold bypass valve to allow exhaust gases from the purge manifold to flow into the intake port while the BTCC valve is closed.In this embodiment of the method, the pre-catalyst can be arranged downstream of where the scavenging manifold bypass channel connects to the exhaust manifold (such as the emission control device 72 shown in Fig. 1A). Therefore, in this embodiment, no additional pre-catalyst (such as a three-way catalytic converter) can be located upstream of where the scavenging manifold bypass channel connects to the exhaust manifold. Both of the methods at 516 and 514 proceed to 530 to determine whether a catalyst located in the exhaust duct is at (e.g., has reached) a start-up temperature. In one example, the catalyst may be part of one or more emission control devices positioned in the exhaust (e.g., the emission control devices 70 and 72 shown in Fig. 1A). If the one or more catalysts are at or above their start-up temperatures (e.g., for efficient catalyst operation), the method proceeds to 532 to adjust the timing of the purge exhaust valves based on internal combustion engine conditions. In one example, the method at 532 may involve adjusting the purge exhaust valves to their default or output timing (e.g., the timing shown in Fig. 3A). The method then terminates. Alternatively, if the temperature of one or more catalysts falls below the activation temperature, the procedure proceeds to 534 to further adjust the internal combustion engine operation to increase the catalyst temperature. In an example, as shown in 536, the procedure in 534 may involve disabling the blow-off exhaust valves of the outer cylinders (e.g., the blow-off exhaust valves 8 of cylinders 12 and 18 shown in Fig. 1A), while all purge exhaust valves (for all outer cylinders and inner cylinders) remain active. For example, the inner cylinders may be physically positioned between the outer cylinders. In this way, only exhaust gas from the inner cylinders can flow to the catalysts within the exhaust duct.The method at 536 can further involve maintaining the fuel supply to the cylinders with the deactivated blow-off valves, but not igniting these cylinders (although sparks are still supplied to the cylinders with the deactivated blow-off valves). In another example, as shown at 538, the method at 534 can involve reducing the opening of a throttle (e.g., throttle 62 shown in Fig. 1A) and opening a valve in a second EGR channel located between the scavenging exhaust manifold and the intake manifold downstream of the compressor and upstream of the throttle (e.g., the second EGR channel 58 shown in Fig. 1A). This can cause air to flow backward through the second EGR channel, from the intake manifold to the scavenging exhaust manifold, and through the scavenging valves into the cylinders.This can lead to an increase in the temperature of blow-through gases routed to the outlet via the blow-off manifold, thereby increasing the catalyst temperature. The method described in 538 may be referred to here as an idle mode and can be explained in more detail below with reference to Figures 7A-7B. In 534, one of the methods described in 536 and 538 may be selected based on the architecture of the internal combustion engine system. For example, the method described in 538 may be used if the system includes the second EGR channel. Otherwise, the method described in 536 may be used. In alternative embodiments, the method described in 534 may select between the methods described in 536 and 538 based on alternative internal combustion engine operating conditions. Returning to 502, if the purge exhaust valves are not enabled by default, they can be disabled (and thus closed) by default. In this case, the procedure proceeds to 518 to advance the timing of the intake valves (e.g., intake valves 2 and 4 shown in Fig. 1A) and to retard the timing of the exhaust valves. Advancing the intake valve timing can adjust one or more intake valve timing mechanisms to advance the closing timing of the intake valves. Furthermore, retarding the exhaust valve timing can involve retarding the opening timing of both the purge exhaust valves and the blow-off exhaust valves together (e.g., if controlled by the cam timing system) or retarding the opening timing of only the blow-off exhaust valves. These adjustments can improve combustion stability during cold starts.In 520, the procedure involves determining whether it is possible to adjust the activation state or timing profile of the purge outlet valves (e.g., similar to the procedure in 508, as described above). If the purge outlet valves cannot be adjusted (e.g., due to an oil pressure that falls below a threshold for changing the valve activation state), the procedure proceeds to 522 to leave the purge outlet valves deactivated. Otherwise, if the purge outlet valves can be adjusted (or reactivated), the procedure proceeds to 524 to determine whether it is possible to switch the purge outlet valves between timing profiles (e.g., similar to the procedure in 512, as described above).If the purge outlet valves cannot be switched between profiles, the procedure proceeds to 526 to activate the purge outlet valves and modulate the BTCC valve to control the EGR flow through the EGR channel and to the compressor inlet to a desired amount. However, if the purge outlet valves can be switched between profiles, the procedure proceeds instead to 528 to change the purge outlet valve profile to an early opening / lift and to close the BTCC valve, as described above in 516. Both of the procedures in 526 and 528 then proceed to 530, as described above. Fig. 16 shows a diagram 1600 for operating the split exhaust gas combustion engine system in cold-start mode. In particular, diagram 1600 shows an on-state of the scavenge exhaust valves (where on is activated and off is deactivated) at curve 1602, a position of the BTCC valve at curve 1604, the EGR flow (e.g., an amount or flow rate of EGR flow through the EGR channel 50 and to the compressor inlet, as shown in Fig. 1A) at curve 1606, a temperature of an exhaust catalyst relative to a catalyst start-up temperature at curve 1608, a position of an intake throttle (e.g., the throttle 62 shown in Fig. 1A) at curve 1610, and a position of a second medium-pressure EGR valve arranged in a second (e.g., medium-pressure) EGR channel (e.g., the one shown in Fig. 1A).1A shows valve 59 in the second EGR channel 58), at curve 1612, and cam timing of the intake valves at curve 1614 and of the exhaust valves (which may include the blow-off exhaust valves and the purge exhaust valves if controlled on the same cam timing system) at curve 1616 relative to their output timing controls B1 (an example of the output cam timing controls of the intake and exhaust valves can be shown in Fig. 3B, as described above). All curves are shown against time along the x-axis. Before time t1, the internal combustion engine starts with the scavenging exhaust valves activated by default. This allows the scavenging exhaust valves to open and close according to their set timing within the engine cycle. At time t1, the BTCC valve opens for the first cranking stroke. Thus, the EGR flow begins to increase after time t1 (and can increase and decrease over time as the BTCC valve opens and closes). After the first cylinder fires, the BTCC valve is modulated to control the EGR flow to a desired level. Between time t1 and time t2, the medium-pressure EGR valve closes, and both the intake and exhaust valve timings are at their output timings. At time t2, the scavenging exhaust valves may be adjusted (e.g., because the oil pressure has reached a threshold to adjust the valves), so the scavenging exhaust valves are deactivated (e.g., because the oil pressure has reached a threshold).The EGR valve is switched off. After time t2, the catalyst temperature is still below the activation temperature T1. Therefore, the throttle opening is reduced and the medium-pressure EGR valve opens to reverse the flow through the system and send warmer intake air to the catalyst within the exhaust manifold. This can cause the catalyst to heat up to a temperature above the activation temperature T1. During another cold start in the split exhaust gas combustion engine system, the engine can start with the purge exhaust valves deactivated (e.g., switched off) by default, as shown at time t3. At time t4, the intake cam timing is advanced and the exhaust cam timing of the blow-off valves is retarded (as shown in trace 328 in Fig. 3B, as described above). At time t5, the purge exhaust valves are activated in response to the fact that the purge exhaust valves can be adjusted, and the BTCC valve is modulated to adjust the EGR flow. In this way, exhaust emissions during the cold start of an internal combustion engine can be reduced by adjusting the activation state of the scavenging exhaust valves, while also controlling the position of the BTCC valve based on a desired EGR flow and pressure in the scavenging exhaust manifold. As described above with reference to Figures 5 and 16, a method during a cold start can involve adjusting the position of a first valve (BTCC valve) located in an exhaust gas recirculation (EGR) channel based on an internal combustion engine operating state, wherein the EGR channel is coupled between a second exhaust manifold (scavenging manifold) coupled to a second set of exhaust valves (scavenging exhaust valves) and an intake port upstream of a compressor, while a portion of the exhaust gases flows through a first set of exhaust valves (blowing exhaust valves) to an exhaust port containing a turbine.A technical effect of adjusting the first valve and / or the first set of exhaust valves in response to an internal combustion engine operating condition during a cold start is to reduce cold start emissions, while also assisting in the warming up of the internal combustion engine, such as increasing the temperature of the internal combustion engine cylinders and / or pistons and / or one or more exhaust catalysts.In another embodiment, a method may involve, in response to the selection of internal combustion engine operating conditions (such as a cold start and / or catalyst temperature below a start-up temperature), deactivating one or more valves of a set of first exhaust valves (blow-off exhaust valves) coupled to a first exhaust manifold which is coupled to an exhaust port, while all valves of a set of second exhaust valves (scavenge exhaust valves) coupled to a second exhaust manifold which is coupled to an intake port via an exhaust gas recirculation (EGR) port are kept active.A technical effect for deactivating one or more of the blow-off valves (such as the blow-off valves of the outer cylinders, as described above in 536 of Method 500) during a cold start consists of increasing the temperature of the internal combustion engine during the cold start and thus reducing the internal combustion engine emissions during the cold start (e.g., the catalyst can reach its starting temperature more quickly than if all blow-off valves were activated). In a further embodiment, a method may involve, while both a second exhaust valve (scavenge exhaust valve) and a first exhaust valve (blow-off exhaust valve) of a cylinder are open, directing intake air through a flow channel (e.g.,The system consists of a medium-pressure EGR channel, which is coupled between an intake manifold and a second exhaust manifold, which is coupled to the second exhaust valve; and furthermore, the intake air is routed through the first exhaust valve into the cylinder and from the second exhaust valve to a first exhaust manifold (blower exhaust manifold), which is coupled to an exhaust duct containing a turbine. A technical effect of routing the intake air in this way, while both the first and second exhaust valves are open, in response to the temperature of a catalyst located in the exhaust duct downstream of the turbine falling below a threshold temperature, is to increase the temperature of the blow-through air to the exhaust duct and thus the temperature of the catalyst. As a result, the catalyst can reach its activation temperature more quickly, and internal combustion engine emissions during cold starts can be reduced. Further on, Fig. 6 shows a method 600 for operating the internal combustion engine system in a DFSO mode. Method 600 can proceed from step 410 of method 400 as described above. At step 602, the method involves stopping the fuel supply to all cylinders to initiate the DFSO mode. The method proceeds to step 604 to deactivate the blow-off valve (e.g., the blow-off valve 8 shown in Fig. 1A) of one or more cylinders and leave all purge valves active. In one example, at step 604, the method involves deactivating the blow-off valve of each cylinder so that no exhaust gas is directed to the catalyst(s) located within the exhaust duct. As a result, oxygen can be reduced to the catalyst (e.g., a three-way catalyst), thus preserving the catalyst function.In another example, the procedure at 604 involves disabling the blow-off valve of a selected number of cylinders (e.g., only a subset of all internal combustion engine cylinders). The selected number can be based on pedal position (e.g., driver torque requirement), estimated exhaust gas temperature, turbine speed of a turbine located in the exhaust duct, and / or the vehicle's deceleration rate (e.g., the rate at which the vehicle is slowing down). As an example, the procedure at 604 can involve disabling all blow-off valves (e.g., each blow-off valve of each cylinder). However, in this example, the turbine may stop rotating, and the catalyst may cool down.Thus, the methods in 602 and 604 can alternatively involve leaving the BDVs of one or more cylinders active and firing the corresponding one or more cylinders to reduce engine braking, ramp up the turbine, and maintain the catalyst temperature (e.g., without decreasing the catalyst temperature). The spark quantity for firing the cylinder(s) can be delayed to reduce torque and increase exhaust heat and engine efficiency. Then, the spark fraction (e.g., the number of cylinders fired with active BDVs) and the spark quantity for firing the cylinder(s) can be determined based on the pedal position, the estimated exhaust temperature, and a vehicle deceleration rate.As another example, if the turbine speed falls below a threshold speed, the selected number of blow-off valves to be deactivated can be smaller than if the turbine speed were to exceed the threshold speed. In this way, the turbocharger lag after the DFSO event can be reduced. For example, the controller can logically determine the number of blow-off valves to be deactivated at 604 and / or the number of cylinders to stop fuel delivery as a function of turbine speed, pedal position, estimated exhaust temperature, and / or vehicle deceleration rate. The controller can then send a control signal to a blow-off valve actuator to deactivate the specified number of blow-off valves. For example, each blow-off valve can have an actuator (such as the one shown in Fig.1A includes actuator 103), which can be used to deactivate and reactivate the associated blow-off outlet valve. In procedure 606, the process involves determining whether there is time to reactivate the bleed exhaust valves of the deactivated cylinders. For example, it may be determined that there is time to reactivate the deactivated bleed exhaust valves at the end of the DFSO event, which may be indicated by an increase in vehicle speed and / or the pressing of an accelerator pedal (e.g., a pedal position depressed beyond a threshold position). If there is no time to reactivate the bleed exhaust valves, the process proceeds to procedure 608 to continue operating the internal combustion engine with the deactivated cylinders (e.g., cylinders with the deactivated bleed exhaust valves). Otherwise, if the DFSO has ended and / or it is time to reactivate the cylinders, the process proceeds to procedure 610 to reactivate the bleed exhaust valves of the deactivated cylinders.As an example, reactivating the blow-off valves of the deactivated cylinders may involve sending a signal to one or more blow-off valve actuation mechanisms to continue operating the blow-off valves at their set timing. Additionally, reactivating the blow-off valves may involve providing sparks to each deactivated cylinder after an intake valve closing event and then opening the deactivated blow-off valve. In 612, the procedure involves reactivating fuel injection to the cylinders and reducing the amount of fuel enrichment to the cylinders. In an example, this may involve reducing the amount of fuel injected into the cylinders compared to a standard fuel injection quantity following a DFSO event (e.g., without deactivating the blow-off valves).Because less oxygen is delivered to the catalyst during the DFSO event due to the deactivation of the blow-off valve, less fuel enrichment is required after the DFSO event. As a result, fuel efficiency is increased compared to conventional DFSO. Fig. 17 shows a diagram 1700 for operating the split exhaust gas internal combustion engine system in DFSO mode. In particular, diagram 1700 shows a pedal position (e.g., accelerator pedal position) at curve 1702, a fuel supply quantity (which is injected into the internal combustion engine cylinders) at curve 1704, an opening state of a blow-off valve (BAV) of a first cylinder at curve 1706, an opening state of a blow-off valve (BAV) of a second cylinder at curve 1708, an opening state of a blow-off valve (BAV) of a third cylinder at curve 1710, an opening state of a blow-off valve (BAV) of a fourth cylinder at curve 1712, the turbine speed at curve 1714, and an opening state of the scavenging valves (SVs) of all cylinders at curve 1716. Before time t1, the pedal position is relatively constant, and the BDVs and SVs of all four cylinders are activated (e.g., switched on). Thus, each BDV can open and close according to a set timing within the internal combustion engine cycle. At time t1, the pedal position decreases, indicating a deceleration event. A DFSO event is initiated by interrupting the fuel supply to some of the internal combustion engine cylinders. As shown at time t1, the fuel supply to cylinders 2-4 can be stopped, but maintained at cylinder 1 to keep the internal combustion engine speed at a threshold, allow the turbine to continue spinning, and keep the catalyst warm and at stoichiometry (thus, the fuel supply does not go to zero between time t1 and time t2).In response to the DFSO event and the deactivation of fuel supply to cylinders 2-4, the BDVs of cylinders 2, 3, and 4 are deactivated, while the SVs for all cylinders remain activated. Consequently, no exhaust gas flows from cylinders 2, 3, and 4 to the exhaust manifold. Instead, exhaust gases from the deactivated cylinders are routed through the SVs and the scavenging exhaust manifold to the intake manifold. At time t2, the pedal position increases, and the DFSO event ends. The BDVs of cylinders 2, 3, and 4 are reactivated, and the amount of fuel supplied to the cylinders may be slightly reduced compared to a DFSO event where no BDVs are deactivated. At time t3, another DFSO event occurs. In response to the DFSO event and the fact that the turbine speed is at a higher level (e.g., higher than at time t1 during the first DFSO event), the BDVs of cylinders 1, 2, 3, and 4 are deactivated. Thus, all BDVs of all cylinders are deactivated (e.g., due to the higher turbine speed at time t3, a larger number of BDVs are deactivated at time t3 than at time t1). In response to the DFSO event ending at time t3, all BDVs are reactivated. In this way, in response to the selection of internal combustion engine operating conditions (such as a DFSO state, where fuel supply to the internal combustion engines is deactivated), one or more valves of a set of first exhaust valves (BDVs) coupled to a first exhaust manifold connected to an exhaust port can be deactivated, while all valves of a set of second exhaust valves (SVs) coupled to a second exhaust manifold connected to an intake port via an exhaust gas recirculation (EGR) port remain active. A technical effect of deactivating one or more BDVs during the DFSO event is to reduce the amount of oxygen delivered to a catalyst in the exhaust port during a DFSO. As a result, catalyst performance can be improved and internal combustion engine emissions can be reduced.Furthermore, reducing the amount of oxygen directed to the catalyst during DFSO can, at the conclusion of the DFSO event, allow for a slight fuel enrichment to be used upon reactivation of the BDVs, thereby increasing the fuel efficiency of the internal combustion engine system. Further, Figures 7A-7B show a method 700 for operating the internal combustion engine system in a gas reaction mode. Method 700 can proceed from step 414 of method 400 as described above. At step 702, the method includes determining whether conditions for operation in a hot-pipe mode are met. In one example, the split exhaust engine system may include a channel coupled between the scavenging exhaust manifold and the intake port downstream of an intake throttle (e.g., channel 30 shown in Figure 1A, referred to herein as a hot pipe). However, in some embodiments, the split exhaust engine system may not include the hot pipe, and thus the conditions for hot-pipe mode would not be met. In one example, hot-pipe mode may be the default mode for best fuel efficiency when the internal combustion engine is throttled (e.g.,(if the throttle opening amount is less than the fully open throttle). Conditions for entering hot-pipe mode include the internal combustion engine system incorporating the hot pipe and may additionally include the failure to limit engine knock. For example, if the engine load falls below a lower threshold (e.g., at very light loads) and the engine can no longer tolerate EGR, the hot-pipe valve may close, and the hot-pipe conditions will not be met. In another example, if the engine load exceeds an upper threshold (e.g., at high engine loads), knock may also occur, and thus the hot-pipe valve may close to force more EGR to the compressor inlet for engine cooling.Thus, the conditions for entering hot pipe mode may include that the knocking of the internal combustion engine is not limited (e.g., the possibility of internal combustion engine knocking falls below a threshold) and that it is able to tolerate increased EGR. When conditions for entering hot pipe mode are met, the procedure proceeds to 704. In 704, the procedure involves closing (e.g., completely closing) the intake throttle, opening the BTCC valve (e.g., valve 54 shown in Fig. 1A), and opening the hot pipe valve (e.g., valve 32 shown in Fig. 1A). As a result, intake air can be directed from the intake manifold upstream of the compressor into the EGR channel (e.g., the first EGR channel 50 shown in Fig. 1A), through an EGR cooler (e.g., the EGR cooler 52 shown in Fig. 1A), into the scavenging exhaust manifold, through the hot pipe (e.g., hot pipe 30 shown in Fig. 1A), into the intake manifold downstream of the intake throttle, and into the internal combustion engine cylinders. The intake air is heated by flowing through the EGR cooler before it enters the internal combustion engine cylinders.This can increase the MAP (Magnetic Output Pressure), reduce the intake pump work of the internal combustion engine, improve fuel efficiency, and reduce internal combustion engine emissions. Additionally, this operation can also reduce the scavenging manifold pressure, thereby increasing the EGR (Exhaust Gas Recirculation) flow. This intake air can then be burned within the internal combustion engine cylinders. A first portion of the combustion gases is then released from the internal combustion engine cylinders through the bleed valves into the bleed manifold. This first portion of the combustion gases then flows through the exhaust port to the turbine and one or more emission control devices. A second portion of the combustion gases is released from the internal combustion engine cylinders through the scavenging valves into the scavenging manifold. This second portion of exhaust gases mixes with intake air within the scavenging manifold, and then the mixture is routed through the hot pipe to the intake manifold.This mixture can reduce the influence of any cylinder during EGR mixing, thus reducing resistance and optimizing manifold flow. In the 706, the procedure involves adjusting (e.g., adjusting a position) the hot pipe valve based on a desired MAP and adjusting the exhaust cam timing based on the internal combustion engine load. As an example, the procedure adjusts the amount of opening (or position) of the hot pipe valve based on a desired MAP, which can be determined based on the internal combustion engine operating conditions. For example, the control unit can determine a control signal sent to the hot pipe valve actuator based on a determination of the desired MAP. The control unit can determine the control signal by a determination that takes a specific desired MAP into account, such as increasing the amount of hot pipe valve opening as the desired MAP increases.The controller can alternatively determine the hot pipe valve opening amount based on a calculation using a lookup table with the desired MAP (mapped manifold absolute pressure) as the input and the hot pipe valve position signal as the output. As another example, the controller can make a logical determination (e.g., regarding an actuator of the scavenging and blow-off exhaust valve cam timing system) based on logical rules that are a function of the internal combustion engine load. The controller can then generate a control signal that is sent to the exhaust valve cam timing actuator. For example, if the internal combustion engine load increases, the cam timing of the exhaust valves (e.g., blow-off and scavenging exhaust valves if controlled by the same cam system) can be advanced. In 708, the procedure involves determining whether conditions for a VDE mode are met, where one or more blow-off valves are disabled. In an example, conditions for entering the VDE mode of one or more cylinders may include a turbine speed above a threshold speed (for example, which may be based on a speed at which turbocharger lag can occur when torque demand increases) and / or an internal combustion engine load below a threshold load. If conditions for operating in VDE mode are met, the procedure proceeds to 710. In 710, the procedure involves disabling the blow-off valve of one or more cylinders. In an example, the number of cylinders for which the blow-off valve is disabled may be based on internal combustion engine load or torque demand. In particular, as the internal combustion engine load decreases, the number of cylinders with blow-off valves disabled may increase.For example, during a first state, the gas reaction state, when the internal combustion engine torque demand falls below a lower threshold, the blow-off exhaust valves of each internal combustion engine cylinder can be deactivated. During the second state, the gas reaction state, when the internal combustion engine torque demand exceeds the lower threshold, only a portion of the blow-off exhaust valves of the internal combustion engine cylinders can be deactivated, with the portion (and thus the number of cylinders with deactivated blow-off exhaust valves) decreasing as the torque demand continues to increase above the lower threshold. Additionally, in 710, all scavenging exhaust valves of all cylinders remain activated during the deactivation of the blow-off exhaust valve. Furthermore, the method in 710 can involve disabling the spark supply to the cylinders with deactivated blow-off exhaust valves while still supplying fuel.In this way, an ignition decision can be made later in the internal combustion engine cycle (since fuel is still being injected). Furthermore, supplying fuel to the deactivated cylinders and pumping the mixture to ignite the cylinders (e.g., cylinders without deactivated blow-off valves) can increase fuel vaporization upon ignition (and thereby reduce smoke). Additionally, the procedure at 710 may involve keeping the hot pipe open and the throttle closed during blow-off valve shutdown. In some examples, the procedure at 710 may involve reactivating the deactivated blow-off valves in response to an increase in torque demand above a threshold and / or a command to fully open the throttle (or the opening of the throttle). The procedure may then terminate. Returning to 702, if the conditions for hot-pipe mode are not met, the procedure proceeds to 712 to determine whether the conditions for an EIVC (early intake valve closing) mode are met. In one example, the decision to enter EIVC mode may be a function of MAP, engine speed, and engine temperature when the engine load falls below a threshold load. In another example, conditions for entering EIVC mode may include the engine load falling below a threshold load and the MAP being at atmospheric pressure (for example, when the engine is not boosted). If conditions for EIVC mode are met, the procedure proceeds to 714.In the case of 714, the procedure involves disabling the intake valves and opening the scavenging exhaust valves (with the timing set for each cylinder) to introduce air into the internal combustion engine cylinders via the scavenging exhaust valves instead of the intake valves. Specifically, the procedure in the case of 714 may involve disabling the intake valves (e.g., both intake valves) of all internal combustion engine cylinders, so that no intake air is introduced into the cylinders via the intake valves. The procedure in the case of 714 may further involve opening (e.g., fully opening) the BTCC valve (if it is not already open). In 716, the procedure involves delaying the timing of the blow-off exhaust valve and the purge exhaust valve to reverse the direction of intake air into the cylinder (e.g., to enter the cylinder via the purge exhaust valves). In one example, the procedure in 716 might involve operating both the purge exhaust valves and the blow-off exhaust valves at a maximum amount of exhaust cam delay (e.g., when controlled by the same cam system). As another example, the procedure in 716 with a cam-in-cam type control system might involve setting the closing of the blow-off exhaust valves to top dead center (TDC) and advancing the purge exhaust valves to reduce the overlap between the purge and blow-off exhaust valves of each cylinder. As yet another example, the procedure in 716 with a cam profile adjustment system might involve changing the cam profiles (e.g.,The system (including the scavenging and blow-off valves) is optimized for EIVC timing. As a result of this process, in EIVC mode, intake air is introduced into the engine cylinders from the intake manifold via the EGR channel, scavenging exhaust manifold, and the scavenging valves. After combustion within the engine cylinders, exhaust gases are released into the exhaust manifold via the blow-off valves. This reduces cylinder pumping work during low loads and improves charge motion for increased combustion stability. Referring again to 712, if conditions for the EIVC mode are not met, the method proceeds to 718 to determine whether conditions for closing a charge motion control valve (CMCV) coupled to an intake port of an intake manifold of each cylinder (such as the CMCVs 24 shown in Fig. 1A) are met. In an example, the conditions for closing the CMCVs may include an internal combustion engine load being below a lower threshold load. If the conditions for closing the CMCVs are met, the method proceeds to 720 to close the CMCV coupled to the intake port of the inlet valve of each cylinder (such as the CMCVs 24 shown in Fig. 1A). For example, the procedure at 720 may involve adjusting the CMCVs to at least partially block the intake flow to the intake valves (e.g., one intake valve as shown in Fig. 1A) of each cylinder.As a result, the turbulence (or swirling) of the intake air flow entering the internal combustion engine cylinders can increase, allowing the intake air to flush an increased amount of exhaust gas from inside the internal combustion engine cylinders and flush the exhaust manifold. If other conditions for closing the CMCV are not met (or are already closed), the procedure proceeds to 722 to determine whether conditions for an idle-boost mode are met. In one example, the condition for entering idle mode involves when the internal combustion engine is idling (for example, when the vehicle speed is below a threshold vehicle speed, which may be zero, and / or when the internal combustion engine speed is below a threshold internal combustion engine speed). As an example, operating in idle-boost mode may allow the scavenging manifold to be vacuum-charged, causing air to purge some of the exhaust gases trapped in the cylinders. This may increase combustion stability and / or increase the heating of one or more catalysts arranged in the exhaust duct.Thus, one example includes a condition for entering idle boost mode when purging gases from the internal combustion engine cylinders is desired. If the conditions in 722 are met, the procedure proceeds to 724. In the 724, the procedure involves closing the turbocharger wastegate (e.g., wastegate valve 76 shown in Fig. 1A) to increase boost pressure and opening a valve in an idle booster pipe (e.g., valve 59 in the second EGR channel 58, shown in Fig. 1A). The idle booster pipe can also be referred to as a second or intermediate-pressure EGR channel and may be coupled between the scavenging exhaust manifold and the intake port downstream of the compressor. By opening the valve in the idle booster pipe while the internal combustion engine load is below a threshold, intake air from downstream of the compressor can flow through the idle booster pipe and into the scavenging exhaust manifold.Thus, when both the scavenging exhaust valve and the blow-off exhaust valve of the same cylinder are open, the intake air can flow from the idle booster pipe through the scavenging exhaust valve into the internal combustion engine cylinder and then through the blow-off exhaust valve to the exhaust port. This can be described as blow-through to the exhaust. This allows exhaust residue to be scavenged from inside the internal combustion engine cylinders to the exhaust port at idle conditions, thereby increasing internal combustion engine stability. In the 724, the procedure can further involve modulating the BTCC valve position to achieve a desired amount of blow-through during an overlap (e.g., opening overlap) period between the blow-off exhaust valve and the scavenging exhaust valve of each cylinder. As an example, the desired amount of blow-through during the overlap period can be determined based on internal combustion engine stability.For example, purging exhaust gas from the cylinders can improve the combustion rate and allow for a richer fuel mixture, thereby increasing stability. However, excessive purge can decrease fuel efficiency and reduce catalyst temperatures. For instance, modulating the BTCC valve position involves opening and closing the BTCC valve to control the purge manifold pressure to a level that produces a desired amount of purge from the purge outlet valve to the blow-off outlet valve while both the purge and blow-off outlet valves are open. As an example, decreasing the amount the BTCC valve opens and / or closes for an extended period can increase the pressure within the purge manifold (e.g., above the exhaust port pressure) and thus increase the amount of purge to the exhaust.As yet another example, the control system can open the scavenging manifold bypass valve (e.g., SMBV 97, shown in Fig. 1A) and adjust a BTCC valve position to increase the scavenging manifold pressure above the exhaust pressure. The excess air in the exhaust gas, generated by the blow-through, can allow rich conditions in the cylinder, which increase internal combustion engine stability while maintaining an overall stoichiometric air-fuel ratio downstream of a catalyst for reduced emissions. In some examples, the procedure at 724 may additionally involve reducing the amount of opening (or complete closing) of the intake throttle. The procedure transitions to 726 and involves controlling exhaust and intake valve overlap to regulate the flow from the scavenging exhaust manifold to the intake manifold. For example, the procedure at 726 may involve adjusting the timing of a cylinder's scavenging exhaust valve and intake valve to adjust the amount of valve overlap between the intake and scavenging exhaust valves and to control the airflow from the scavenging exhaust manifold to the intake manifold to a desired level. The desired air level for the intake manifold may be varied based on the internal combustion engine load. For example, in response to increasing engine load, the control may send signals to timing actuators of the scavenging exhaust and intake valves to increase the amount of valve overlap between the intake and scavenging valves of each cylinder, thereby increasing the airflow from the scavenging manifold to the intake manifold.As an example, the control unit can make a logical determination regarding the timing of the intake and exhaust valves based on logic rules that are a function of the internal combustion engine load. The control unit can then generate a control signal that is sent to the intake and exhaust valve timing actuators. The method can then proceed to 728 to further control boost and blow-through to desired levels by switching on (and operating) one or more of an electric compressor (e.g., the electric compressor 60 shown in Fig. 1A), increasing the opening of the turbocharger wastegate, adjusting the ignition retard, and / or adjusting the cam timing to match the scavenge and blow-off valve overlap. As an example, the method at 728 can involve increasing the amount of wastegate opening in response to a requirement to decrease a scavenge manifold pressure and to reduce an amount of blow-through air flowing from the scavenge manifold to the blow-off manifold. As another example, operating the electric compressor can improve blow-through capability by providing increased pressure to the scavenge manifold.In yet another example, increased ignition retard can be used in response to a request for more exhaust blow-off. In yet another example, in systems where the blow-off and purge valve overlap can be varied (e.g., via a cam-in-cam type system), the overlap can be increased to enhance blow-off. Referring again to 722, if the conditions for the idle boost mode are not met, the method proceeds to 730 of Fig. 7B. As an example, the conditions for the idle boost mode may not be met if it is determined that it is time to measure the EGR retraction into a purge outlet valve line. In 730, the method involves determining whether the internal combustion engine is idling (e.g., if an accelerator pedal is not pressed and / or the internal combustion engine is disengaged from the vehicle's drivetrain). If the internal combustion engine is idling, the method proceeds to 732 to determine the amount of EGR that has retracted into the line (e.g., exhaust port) of each purge outlet valve, based on the oxygen level measured by a lambda sensor positioned in the exhaust line of each purge outlet valve.For example, a lambda sensor can be positioned in the exhaust line of each purge exhaust valve (such as the lambda sensors 38 shown in Fig. 1A), and thus an output from each lambda sensor can provide an estimate of the EGR retraction for each cylinder. At 734, the method involves adjusting the exhaust valve timing (e.g., the purge exhaust valves and blow-off exhaust valves) to adjust the EGR flow based on the estimated amount of EGR retraction at each internal combustion engine cylinder. This can involve, for example, advancing the exhaust valve timing to increase the EGR flow in response to increasing EGR retraction. As another example, the control can make a logical determination (e.g., with respect to the exhaust valve timing) based on logic rules that are a function of the EGR retraction into the purge exhaust valve lines.The control unit can then generate a control signal which is sent to the exhaust valve timing actuators. Alternatively, if the internal combustion engine is not idling at 730, the process ends. Figures 18A-18B show a diagram 1800 for operating the split exhaust gas combustion engine system in a gas reaction mode. In particular, diagram 1800 shows the internal combustion engine load at curve 1802, the position of an intake throttle (e.g., intake throttle 62, shown in Fig. 1A) at curve 1804, the position of the BTCC valve (e.g., valve 54, shown in Fig. 1A) at curve 1806, the position of the hot pipe valve (e.g., valve 32, shown in Fig. 1A) at curve 1808, MAP relative to atmospheric pressure (ATM) at curve 1810, the on / off state (e.g., on and operating or off and deactivated) of the intake valves at curve 1812, the on / off state of the scavenging exhaust valves (e.g., valves 6, shown in Fig. 1A) at curve 1814, and the position of the CMCVs (e.g., CMCVs 24, shown in Fig. 1A) at curve 1814. 1816, a position of the idle speed booster pipe valve (e.g. valve 59, shown in Fig. 1A) at route 1818, a position of the turbocharger wastegate (e.g.Wastegate 76 (shown in Fig. 1A) at path 1820, an operating state of an electric compressor (the electric compressor 60, shown in Fig. 1A, where indicates that the electric compressor is driven by an electric motor of the electric compressor), a pressure in the purge exhaust manifold (e.g., output of pressure sensor 34, shown in Fig. 1A) at path 1824, a pressure at the compressor inlet of the turbocharger compressor (e.g., output of pressure sensor 31, shown in Fig. 1A) at path 1826, an activation state of a first blow-off valve (BDV) of a first cylinder at path 1828, and an activation state of the blow-off valves (BDVs) of a second, third, and fourth cylinder at path 1830. Although the valve positions in Figs. 18A-18B can be shown as open and closed, the valves can be configured in a variety of ways. Positions can be adjusted between fully open and fully closed. Before time t1, the internal combustion engine load is above a lower threshold load L1, and the throttle is fully open. An internal combustion engine load below the lower threshold load L1 can indicate a low-load state in which the throttle is at least partially closed (e.g., not fully open). Thus, before time t1, the internal combustion engine load is above this low-load threshold. At time t1, the internal combustion engine load drops below the lower threshold load, and the throttle position decreases (e.g., the amount of throttle opening decreases). The internal combustion engine may also be boosted at time t1 (e.g., MAP greater than ATM). In response to this low-load state at time t1, immediately after time t1, the throttle is closed, the BTCC valve is open, and the hot-tube valve is open to operate the internal combustion engine in hot-tube mode.The CMCVs can be kept closed during the low-load condition at time t1. Furthermore, the first cylinder's BDV can be switched off immediately after time t1 in response to the engine load being below the lower threshold load. However, the BDVs of the second, third, and fourth cylinders can remain switched on. As a result, no exhaust gas moves from the first cylinder to the exhaust port while the first cylinder's BDV is switched off. In alternative embodiments, additional BDVs of additional cylinders can be switched off in response to the low-load condition. For example, if the engine load were to fall further below the lower threshold load L1 between times t1 and t2, the control system could switch off the BDVs of two or more cylinders (instead of just one, as shown at time t1). At time t2, the internal combustion engine load increases above the lower threshold load L1, and the throttle position gradually returns to the fully open position (e.g., wide-open throttle). Thus, one hot pipe valve is closed at time t2. Furthermore, the CMCVs open, and all BDVs are switched on at time t2. The electric compressor is also switched on at time t2 to increase the gain. Because the compressor inlet pressure is higher than the purge exhaust manifold pressure at time t2, the BTCC valve is also closed. The BTCC valve opens again before time t3. In response to the BTCC valve opening, the CMCVs close. At time t3, the internal combustion engine load again falls below the lower threshold load L1. In response to this low-load state and the fact that the conditions for EIVC mode are met, the intake valves of all internal combustion engine cylinders are closed at time t3. In some examples, the exhaust cam timing of the BDVs and SVs may be delayed to allow intake air to be introduced into the internal combustion engine cylinders via the SVs and expelled from the BDVs during EIVC mode. At time t4, the internal combustion engine load increases above the lower threshold load L1. As a result, the intake valves are opened again. Before time t5, the wastegate opens. In one example, the wastegate may open in response to the turbine speed increasing above a threshold turbine speed.For example, a turbine speed above the threshold turbine speed can lead to a compressor outlet temperature that is higher than an upper threshold (e.g., to reduce turbocharger degradation). At time t5, the internal combustion engine load again falls below the lower threshold load L1. In response to this low-load state and the fact that the conditions for idle boost mode are met, the idle boost tube valve opens and the wastegate closes. Additionally, the BTCC valve is modulated to achieve a desired blow-through rate during the BDV and SV overlap periods. At time t6, the internal combustion engine load increases above the lower threshold load, and the idle boost tube valve closes. In this way, the reverse flow through the EGR channel to the internal combustion engine cylinders via the scavenging exhaust valves can be reduced during a gas reaction state, which can cause reduced mixing and cylinder balance. As an embodiment of a method during a gas reaction state, a method includes: directing intake air from an intake port to a second exhaust manifold (scavenging manifold) coupled to a second set of cylinder exhaust valves (scavenging exhaust valves) via an exhaust gas recirculation (EGR) channel; heating the intake air as it passes through an EGR cooler in the EGR channel; directing the heated intake air to an intake manifold downstream of an intake throttle via a flow channel (hot pipe) coupled between the second exhaust manifold and the intake manifold; and expelling combustion gases via a first set of cylinder exhaust valves (blower exhaust valves) to a first exhaust manifold.which is coupled to the exhaust port. One technical effect of routing the intake air in this way, through the hot pipe, during a gas reaction condition (or when the internal combustion engine load is below a threshold load), is to improve the mixing of EGR from each cylinder with the incoming intake air, reduce cylinder pumping work, heat the intake air via the EGR cooler to increase MAP, further reduce intake pumping work, and improve fuel efficiency and reduce emissions. As another embodiment of a method during a gas reaction condition, a method in response to an internal combustion engine load below a threshold involves shutting off all intake valves of an internal combustion engine cylinder while operating a second exhaust valve (scavenge exhaust valve) coupled to an exhaust gas recirculation (EGR) port, which is coupled to an intake port.a first exhaust valve (blower exhaust valve) coupled to an exhaust port at different times; and directing the intake air from the intake port through the EGR port and into the internal combustion engine cylinder via the second exhaust valve. A technical effect of shutting off all intake valves during the gas reaction state is to heat the intake air via an EGR cooler located in the EGR port, reducing pumping work and improving fuel efficiency. As yet another embodiment of a method during the gas reaction state, a method in response to an internal combustion engine load below a lower threshold load involves adjusting a first set of swirl flaps (e.g., CMCVs) coupled upstream of a first set of intake valves to at least partially block the intake air flow to the first set of intake valves, each cylinder having two intake valves,including one of the first set of intake valves, and two exhaust valves. A technical effect of adjusting the first set of swirl flaps to at least partially block the intake airflow to the first set of intake valves is to increase the turbulence of the intake airflow entering the cylinders via the first set of intake valves, thereby improving the scavenging of the remaining burnt exhaust gases from the combustion chambers. As a result, internal combustion engine emissions can be reduced and internal combustion engine efficiency can be increased. Yet another embodiment of a method during the gas reaction state involves, in response to internal combustion engine load below a threshold and while a first set of exhaust valves and a second set of exhaust valves are simultaneously open: directing intake air through a secondary flow channel (idle boost channel),which is coupled between an intake duct downstream of a compressor and a second exhaust manifold, the second exhaust manifold being coupled to the second set of exhaust valves; heating the intake air, which is routed through the secondary flow duct, via an EGR cooler coupled to the second exhaust manifold; and routing the heated intake air through internal combustion engine cylinders and to a first exhaust manifold, the first exhaust manifold being coupled to the first set of exhaust valves and an exhaust duct containing a turbine, via the second set of exhaust valves, through the internal combustion engine cylinders, and via the first set of exhaust valves. The technical effect of routing the intake air through the secondary flow duct in this manner while the internal combustion engine load is below the threshold,This consists of allowing the remaining exhaust gas to be forced out of the cylinder and into the exhaust port before the second exhaust valve closes. As a result, internal combustion engine efficiency and fuel efficiency can be improved even under gaseous reaction conditions. Fig. 8 shows a method 800 for operating the internal combustion engine system in an electric amplification mode. Method 800 can proceed from step 418 of method 400 as described above. Thus, during method 800, the electric motor of the electric compressor can drive the electric compressor (e.g., driving a rotor of the electric compressor to increase the intake air pressure). At step 802, the method involves determining whether a compressor inlet pressure is above a scavenge manifold pressure. As an example, the compressor inlet pressure can be a pressure at the inlet (or directly upstream) of the turbocharger compressor (e.g., compressor 162, shown in Fig. 1A). As another example, the compressor inlet pressure can be a pressure at an outlet of the EGR channel (e.g. where the channel 50 couples to the intake channel in Fig. 1A upstream of the compressor 162).In one example, the compressor inlet pressure can be measured via a pressure sensor positioned in the intake duct upstream of the turbocharger compressor (e.g. Pressure sensor 31, shown in Fig. 1A). In an alternative example, the compressor inlet pressure can be estimated by the control system based on one or more alternative internal combustion engine operating parameters (such as a pressure upstream of the point where the electric compressor couples to the intake manifold). Furthermore, the scavenge manifold pressure can be a pressure of the scavenge exhaust manifold (e.g., scavenge exhaust manifold 80, shown in Fig. 1A). In one example, the scavenge manifold pressure can be measured by a pressure sensor located in the scavenge manifold (e.g., pressure sensor 34, shown in Fig. 1A). In another example, the scavenge manifold pressure can be estimated or measured by a plurality of pressure sensors positioned in the exhaust lines of the scavenge outlet valves. When the compressor inlet pressure exceeds the scavenge manifold pressure, the method proceeds to 804 to control (e.g., adjust) a position of the BTCC valve (e.g., valve 54, shown in Fig. 1A) and / or to turn off the scavenge outlet valves (SVs, e.g., outlet valves 6, shown in Fig. 1A) to reduce the blow-through to the outlet. In one example, the method at 804 can involve one or more of reducing the amount of opening of the BTCC valve and turning off the SVs in response to a scavenge manifold pressure being below the turbocharger compressor inlet pressure while the electric motor is driving the electric compressor. In one example, the BTCC valve can be a two-position valve that can be adjusted to a fully open and a fully closed position.In another example, the BTCC valve can be a continuously adjustable valve that can be adjusted to a fully open position, a fully closed position, and a multitude of positions between fully open and fully closed. In this example, the amount by which the BTCC valve opens can decrease as the purge manifold pressure falls below the compressor inlet pressure. In yet another example, the controller can shut off the safety valves when the purge manifold pressure falls below the compressor inlet pressure by a threshold value. As an example, the procedure adjusts the amount by which the BTCC valve opens based on the purge manifold pressure. For instance, the controller can determine a control signal to be sent to the BTCC valve actuator (or the SV actuator, which controls the SVs' on-state) based on a purge manifold pressure reading. The controller can determine the BTCC valve position (open, closed, or a position between fully open and fully closed) by a setting that directly considers a specific position, such as reducing the opening amount as the purge manifold pressure decreases. Alternatively, the controller can determine the BTCC valve position or the SVs' on-state based on a lookup table calculation, where the purge manifold pressure is the input and the BTCC valve position (or the SV on-state) is the output.As another example, the controller can make a logical determination (e.g., regarding the position of the BTCC valve) based on logic rules that are a function of the scavenge manifold pressure. The controller can then generate a control signal that is sent to the actuator of the BTCC valve (and / or the SVs). Adjusting the BTCC valve and / or the SVs in this way at 804 prevents the reverse flow of gases from the scavenge manifold to the exhaust manifold and exhaust port via the SVs and BDVs, which can occur because the scavenge manifold has a lower pressure than the intake port at the compressor inlet. The procedure proceeds to 808 to determine whether the electric motor has stopped driving the electric compressor (e.g., the electric compressor is running and no longer augmenting the intake air). If the electric motor has stopped driving the electric compressor, the procedure proceeds to 812 to re-enable the safety valves (if they were turned off at 804) and / or to open the BTCC valve (if it was closed at 804 or the opening amount was reduced). At 812, the procedure further involves adjusting the position of the BTCC valve based on a desired EGR flow rate. As an example, the controller can make a logical determination (e.g., regarding the position of the BTCC valve) based on logic rules that are a function of a particular desired EGR flow rate. The controller can then generate a control signal that is sent to the actuator of the BTCC valve.Additionally or alternatively, the procedure at 812 can involve returning to 420 from procedure 400. Referring again to 808, if the electric motor is still driving the electric compressor, the procedure proceeds to 810 to further adjust the BTCC valve and the SVs based on the scavenge manifold pressure, as described above and below. The procedure may then return to 802 to recheck the scavenge manifold pressure relative to the compressor inlet pressure. If the compressor inlet pressure is no longer greater than the scavenge manifold pressure, the procedure may proceed to 806 to reopen the BTCC valve if it was closed and / or re-enable the SVs if they were closed. The BTCC valve is then controlled (e.g., adjusted) to deliver the requested (e.g., desired) EGR flow and / or blow-through to the intake manifold.In this way, reverse flow through the EGR channel, through the scavenging manifold, through the internal combustion engine cylinders and to the exhaust manifold can be reduced while the electric compressor is working to boost the intake air, and when the intake air pressure at the compressor inlet (and at the point where the EGR channel couples to the intake manifold) is above the scavenging manifold pressure. Fig. 19 shows a diagram 1900 for operating the split exhaust combustion engine system in electric amplification mode. In particular, diagram 1900 shows an operating state of an electric compressor (e.g., the electric compressor 60, shown in Fig. 1A) at curve 1902, a pressure in the scavenging exhaust manifold (e.g., the output of pressure sensor 34, shown in Fig. 1A, here referred to as the scavenging manifold pressure) at curve 1904, a pressure at the turbocharger compressor inlet (e.g., the output of pressure sensor 31, shown in Fig. 1A, here referred to as compressor inlet pressure) at curve 1906, an activation state of the scavenging outlet valves (SVs) at curve 1908, and a position (open, closed, or somewhere between fully open and fully closed) of the BTCC valve (e.g., valve 54, shown in Fig. 1A) at curve 1910. Before time t1, the electric compressor is off (e.g., not driven by the electric motor), and the scavenge manifold pressure is higher than the compressor inlet pressure. At time t1, the electric motor begins driving the electric compressor, and as a result, the compressor inlet pressure (of the turbocharger compressor) begins to rise. However, since the scavenge manifold pressure is higher than the compressor inlet pressure between time t1 and time t2, the BTCC valve and the SVs are adjusted based on a desired EGR flow rate and blow-through level relative to the intake manifold (e.g., based on the internal combustion engine operating conditions). At time t2, while the electric compressor is operating, the scavenge manifold pressure drops below the compressor inlet pressure. In response, the BTCC valve opening is reduced. As shown in Fig.As shown in Figure 19, the opening amount of the BTCC valve is reduced, but the BTCC valve does not close completely. In alternative embodiments, the BTCC valve may be fully closed, or the SVs may be switched off, in response to the compressor inlet pressure increasing above the scavenge manifold pressure. At time t3, the scavenge manifold pressure increases above the compressor inlet pressure. As a result, the opening amount of the BTCC valve returns to a required level based on a desired EGR flow rate. In one example, as shown at time t3, this may include the fully open position. After time t3 (and after the BTCC valve has fully opened), the electric compressor is no longer driven by the electric motor. At time t4, the electric compressor is driven again by the electric motor. At this time, however, the compressor inlet pressure is below the scavenge manifold pressure, so the current position of the BTCC valve and the activation state of the safety valves are maintained. In response to the compressor inlet pressure rising above the scavenge manifold pressure at time t5, the safety valves (of all internal combustion engine cylinders) are deactivated. At time t5, the electric compressor stops operating. In response to the electric compressor no longer being driven by an electric motor, the safety valves are reactivated. Shortly thereafter, the compressor inlet pressure drops below the scavenge manifold pressure. In this way, the position of the BTCC valve and / or the activation state of the purge outlet valves can be controlled in response to the operation of an electric compressor to reduce reverse flow through the EGR channel, via the purge outlet valves, to the exhaust manifold. A technical effect of adjusting the position of the BTCC valve in response to an electric motor driving the electric compressor, based on the pressure in the purge exhaust manifold, is to reduce reverse flow through the EGR channel, via the purge outlet, to the exhaust manifold while the compressor inlet pressure is higher than the purge manifold pressure. This improves the efficiency of the internal combustion engine and reduces internal combustion engine emissions. Fig. 9 shows a method 900 for operating the internal combustion engine system in a compressor threshold mode. Method 900 can proceed from step 421 of method 400, as described above. The method begins at step 902 by determining whether the conditions for medium-pressure EGR are met. In one example, the internal combustion engine system may include a medium-pressure EGR channel (e.g., the second EGR channel 58, shown in Fig. 1A) coupled between a low-pressure EGR channel (e.g., the first EGR channel 50, shown in Fig. 1A) and an intake port downstream of the turbocharger compressor. Flowing exhaust gases from the scavenging manifold to the intake port via the medium-pressure EGR channel can provide medium-pressure EGR to the internal combustion engine's intake system.Since the exhaust gases are discharged downstream of the compressor via the medium-pressure EGR channel, the temperature at the compressor and / or the compressor speed can be reduced, while exhaust gases from the purge exhaust manifold are routed to the inlet via the medium-pressure EGR channel. In one example, the conditions for activating medium-pressure EGR (e.g., conditions for allowing exhaust gases to flow from the scavenging manifold to the intake manifold, downstream of the compressor via the medium-pressure EGR channel) can be one or more of the EGR demand (e.g., desired EGR flow) above a threshold level (e.g., high EGR demand), the absence of an EGR cooler in the EGR system (e.g., no EGR cooler in the first EGR channel, such as EGR cooler 52, shown in Fig. 1A), or the absence of a compressor bypass in the internal combustion engine system (e.g., compressor recirculation channel 41, shown in Fig. 1A).1A) , an exhaust gas temperature from the purge outlet valves above an upper threshold temperature and / or compressor flow conditions (e.g., if the flow through the compressor is above an upper threshold, EGR cannot be added to the compressor inlet without degrading compressor operation / efficiency). If one or more conditions for activating medium-pressure EGR are met, Method 904 proceeds to close the BTCC valve (e.g., valve 54, shown in Fig. 1A) and open the medium-pressure EGR valve (e.g., valve 59, shown in Fig. 1A), which is located within the medium-pressure EGR valve. For example, opening the medium-pressure EGR valve may involve a controller sending a signal to an actuator of the medium-pressure EGR valve to fully open the medium-pressure EGR valve or to increase the amount of opening of the medium-pressure EGR valve (e.g., from a fully closed position).Closing the BTCC valve can involve completely closing the BTCC valve, such that no exhaust gases are directed to the intake duct upstream of the compressor. In an alternative embodiment, the method at 904 can involve opening the intermediate-pressure EGR valve and reducing the degree of opening of the BTCC valve (but not completely closing it) or keeping the BTCC valve open. For example, in response to compressor pumping conditions, both the BTCC valve and the intermediate-pressure EGR valve can open. In yet another embodiment, the method at 904 can involve increasing the amount of opening of the medium-pressure EGR valve while decreasing the amount of opening of the BTCC valve, wherein the amount of increasing and decreasing the amount of opening of these valves is based on the compressor conditions (e.g. inlet temperature, outlet temperature and rotational speed).For example, the control unit can determine a control signal to be sent to the actuators of the BTCC valve and the medium-pressure EGR valve based on a determination of the compressor inlet temperature, compressor outlet temperature, and / or the compressor speed. These compressor conditions can be measured via one or more sensors in the system (as shown in Fig. 1A) or determined based on operating conditions such as internal combustion engine speed and load and / or air-fuel ratio.The controller can determine the desired position of the BTCC and medium-pressure EGR valves by a determination that directly takes into account specific compressor conditions, such as increasing the opening amount of the medium-pressure EGR valve and decreasing the opening amount of the BTCC valve as the compressor outlet temperature increases, the compressor speed decreases, and / or the compressor inlet temperature decreases (e.g., above / below the thresholds described above with reference to 420 in Fig. 4A). Alternatively, the controller can determine the valve positions based on a calculation using a lookup table, where the compressor conditions are the input and the signal sent to the valve actuators is the output, corresponding to a valve position of the BTCC and medium-pressure EGR valves. The procedure ends according to 904.In alternative embodiments, the procedure can proceed from 904 to 906 to determine whether additional internal combustion engine actuator adjustments are desired to move the compressor away from operating at the operating thresholds. With further reference to 902, if the conditions for medium-pressure EGR are not met or additional actuator adjustments are desired to move the compressor away from operating at or above the operating thresholds, the procedure proceeds to 906. In 906, the procedure involves determining whether condensate is forming at the compressor (e.g., at the compressor inlet). In one example, it may be determined that condensate forms at the compressor in response to a compressor inlet temperature (e.g., a temperature of the gases entering the compressor inlet) being below a first threshold temperature. In another example, it may be determined that condensate forms, or is expected to form, at the compressor when the ambient humidity is above a threshold humidity value and / or when the ambient temperature is below a threshold temperature.If condensate forms at the compressor (or its formation is expected in some examples), the procedure proceeds to 908 to retard the exhaust valve cam (e.g., camshaft) timing to reduce the amount of EGR flowing from the scavenging manifold to the intake port upstream of the compressor via the EGR channel. Retarding the exhaust valve cam timing may involve retarding the timing of only the scavenging exhaust valves or both the scavenging and blow-off exhaust valves, based on the valve timing hardware of the internal combustion engine system. By retarding the timing of the scavenging exhaust valves, each scavenging exhaust valve may open and close later in the internal combustion engine cycle (e.g., open at -90 degrees of crankshaft angle relative to TDC vs. approximately -135 degrees of crankshaft angle, as shown in Fig. 3B, as described above). As above with respect to Fig.As described in Figures 1A-1B, various variable camshaft timing (VCT) systems can be used to achieve delayed timing of the scavenging exhaust valves (and possibly the blow-off exhaust valves). In one example, which could be the basic internal combustion engine system, both the scavenging exhaust valves and the blow-off exhaust valves can be controlled together by a single camshaft system. Thus, delaying the exhaust cam results in a delay in the timing of both the scavenging and blow-off exhaust valves (even if the opening and closing timing of the scavenging exhaust valves differs from that of the blow-off exhaust valves). In this way, the timing of both the scavenging and blow-off exhaust valves can be delayed by the same amount using the single camshaft system.In another example, the VCT system for the exhaust valves can include a cam-in-cam system in which the timing of the purge exhaust valves and the blow-off exhaust valves can be varied independently of the set timings. In yet another example, the VCT system for the exhaust valves can include a MultiAir-type system for the purge exhaust valves. In this system, the opening timing and stroke for the purge exhaust valves can be controlled individually and separately from the blow-off exhaust valves (e.g., in this case, only the timing of the purge exhaust valves is delayed). In yet another example, the VCT system for the exhaust valves can include an electric valve stroke control at the purge exhaust valves, in which the timing of the purge exhaust valves can be set separately from the blow-off exhaust valves (e.g.,delayed, while maintaining the timing of the blow-off valves). In procedure 910, the process involves determining whether the exhaust valve timing (of the purge exhaust valves) is at its maximum amount of delay. For example, the purge exhaust valve timing may only be delayed by a set number of crank angle degrees. Once the exhaust valve timing reaches its maximum amount of delay (e.g., a maximum adjustment amount), the exhaust valve timing cannot be delayed further. If the purge exhaust valve timing reaches its maximum amount of delay while condensate is present at the compressor (e.g., when the compressor inlet temperature is below the first threshold temperature), the process proceeds to procedure 912 to further delay the purge exhaust cam timing. In some examples, this may involve delaying the exhaust cam to its maximum amount of delay.In other examples, this may involve delaying the exhaust cam to an amount of delay that is less than the maximum amount of delay. If, at 910, the maximum amount of delay for the exhaust cam has been reached and the scavenge exhaust valve timing cannot be delayed any further, the procedure proceeds to 914 to determine whether the intake cam of the intake valves can be advanced. Advancing the intake valve timing can result in more overlap between an intake valve and a scavenge exhaust valve of each cylinder, thereby increasing the amount of hot blow-through recirculation to the compressor inlet. This can lower the compressor inlet temperature and reduce condensation at the compressor. The intake cam may be able to be advanced if it has not already been advanced to its furthest-advance position (for example, if it is not already at its maximum advance amount).If the intake cam can be advanced to advance the timing of the intake valves, the method proceeds to 916 to advance the timing of the intake valves. This may involve actuating the intake cam (e.g., intake cam 151, shown in Fig. 1B) via an intake valve timing actuator (e.g., intake valve timing actuator 101, shown in Fig. 1B) to advance the intake valve timing and thus open and close each intake valve earlier or later in the internal combustion engine cycle. Otherwise, if the intake cam cannot be advanced further, the method proceeds from 914 to 918 to close the BTCC valve. For example, the method at 918 may involve completely closing the BTCC valve to control the flow of exhaust gases from the scavenging manifold (e.g.,to block the flow of exhaust gases from the purge manifold to the compressor inlet, thereby reducing low-pressure EGR and condensate formation at the compressor. The method at 918 can further include opening a purge manifold bypass valve (SMBV) located in a bypass channel coupled between the purge manifold and the exhaust duct (e.g., SMBV 97 in bypass channel 98, shown in Fig. 1A). For example, the controller can send a signal to an actuator of the SMBV to open the SMBV in response to the closing of the BTCC valve. As a result, exhaust gases can be routed from the purge manifold to the exhaust duct while the BTCC valve is closed. In alternative embodiments, the method at 918 can decrease the degree of opening of the BTCC valve (without fully closing) and increase the degree of opening of the SMBV (without fully opening).In some examples, the amount of increasing the amount of opening the SMBV may be approximately the same as the (e.g., proportional to) the amount of decreasing the amount of opening the BTCC valve. Referring again to 906, if no condensate forms at the compressor or its formation is not expected (e.g., if the compressor inlet temperature is not below the first threshold temperature), the method proceeds to 920 to determine whether the compressor outlet temperature is above a second threshold temperature. In one example, the compressor outlet temperature (e.g., a temperature of gases exiting the turbocharger compressor) can be measured by a temperature sensor positioned downstream of or at the compressor outlet (e.g., temperature sensor 43, shown in Fig. 1A). In other examples, the compressor outlet temperature can be estimated based on various other sensor outputs and internal combustion engine operating conditions, such as the compressor inlet temperature and a compressor rotational speed, or an intake manifold temperature.If the compressor outlet temperature exceeds the second threshold temperature, the procedure switches to 922. In the case of 922, the method involves modulating the BTCC valve to reduce the amount of exhaust gas flow to the compressor inlet from the scavenge manifold, opening the SMBV, and / or opening the turbine wastegate (e.g., wastegate 76, shown in Fig. 1A). In one example, modulating the BTCC valve may involve switching the BTCC valve between the fully open and fully closed positions to reduce the amount of exhaust gas flow to the compressor inlet via the EGR channel (compared to when the BTCC valve remains fully open) to a first level. Modulating the BTCC valve may also involve increasing the period during which the BTCC valve is closed compared to the period during which it is open.The modulation amount, or the average time the BTCC valve is closed, can be based on the compressor outlet temperature and / or a desired EGR flow rate. For example, if the compressor outlet temperature continues to rise above the second threshold temperature, the BTCC valve can be closed for a longer period, and / or the average time the BTCC valve is closed during the modulation period can increase. In some examples, the procedure at 922 might involve fully closing the BTCC valve. In yet another example, the procedure at 922 might involve reducing the opening amount of the BTCC valve (e.g., to a position between fully open and fully closed, with no modulation).The procedure at 922 can additionally involve opening the SMBV or increasing the degree of SMBV opening while the BTCC valve is closed or modulating between open and closed. Additionally or alternatively, the procedure at 922 can involve opening the turbine wastegate while modulating the BTCC valve. Opening the turbine wastegate reduces the turbocharger speed and can thus reduce the load on the compressor. The procedure proceeds to 924 to advance the intake cam of the intake valves to reduce a pressure ratio across the compressor. For example, the intake cam can be advanced while the position of the BTCC valve is modulated to reduce the EGR flow to the compressor inlet to the first level. The procedure then proceeds to 926 to retard the exhaust cam to delay the exhaust valve opening timing (e.g., of at least the scavenge exhaust valves) to further reduce EGR. For example, retarding the exhaust cam can reduce the EGR flow to the compressor inlet to a second level, which is below the first level. At 928, the procedure involves reducing cold recirculation by opening the BTCC valve. Since the EGR flow is reduced due to the delay of the exhaust valve (e.g.,The purge outlet valve timing control at 926 is reduced, while opening the BTCC valve at 928 increases the flow of pressurized, colder air back to the compressor inlet, thus lowering the compressor temperature. Referring again to 920, if the compressor outlet temperature is not above the second threshold temperature, the procedure proceeds to 930 to determine whether the compressor is operating at an alternative compressor constraint (e.g., threshold). For example, the compressor speed (e.g., compressor rotational speed) may be above a threshold speed, which can lead to a deterioration of the compressor's reduced performance. If the compressor is operating at the alternative constraint, such as a compressor speed above the threshold speed, the procedure proceeds to 932 to close the BTCC valve and open the SMBV. In an example, this might involve fully closing the BTCC valve and fully opening the SMBV.In another example, the procedure at 932 can involve decreasing the amount of opening of the BTCC valve (without fully closing it) and increasing the amount of opening of the SMBV (without fully opening it). The amount of decreasing the BTCC valve opening and the amount of increasing the SMBV opening can be based on a desired purge manifold pressure, where the purge manifold pressure is based on the intake manifold pressure and a timing of the intake and exhaust valves. For example, the amount of overlap between the purge exhaust valve and the intake valve when both are open can determine the time available for purge air, but the pressure differential between the intake manifold (e.g., MAP) and the purge manifold can determine the driving pressure for the purge flow.When MAP is above the scavenging manifold pressure, excess oxygen can flow to the exhaust manifold via the scavenging manifold bypass channel. The desired drive pressure for the blow-through flow can be based on desired oxygen levels in the exhaust, as discussed above with reference to Figures 2A-2B. Thus, if the intake manifold pressure increases, the desired scavenging manifold pressure can decrease for a given intake and exhaust valve timing and a desired blow-through amount. For example, the controller can determine the desired scavenging manifold pressure by a determination that directly considers a given intake manifold pressure and the current intake and exhaust valve timing, and then determines the appropriate positions of the BTCC valve and SMBV to achieve the desired scavenging manifold pressure. As another example, the controller can make a logical determination (e.g.,(with regard to the position of the BTCC valve and the SMBV) based on logical rules that are a function of the intake manifold pressure, intake valve timing, and exhaust valve timing. The controller can then generate a control signal that is sent to the actuators of the BTCC valve and the SMBV. In 934, the procedure involves advancing the purge outlet valve timing (e.g., the opening timing of the purge outlet valves) while the BTCC valve is closed (or while the amount of opening of the BTCC valve is being reduced). For example, the amount of advance used to open the purge outlet valve may increase if the amount of blow-through to the exhaust port decreases (e.g., to a second downstream catalyst in the exhaust port, as shown in Fig. 1A). The procedure then proceeds to 936 to increase the opening of the turbine wastegate, thereby reducing the turbocharger speed. If the compressor is not in an alternative restriction position, the procedure at 930 alternatively proceeds to 938 to keep the turbine wastegate closed. In some embodiments, the standard position of the turbine wastegate may be closed. The wastegate can then only be opened at high turbocharger speeds. The procedure at 938 may involve reverting to procedure 400 from Figures 4A-4B. Fig. 20 shows a diagram 2000 for operating the split exhaust gas combustion engine system in compressor threshold mode. In particular, diagram 2000 shows the internal combustion engine load for the period 2002, the EGR requirement (e.g., desired EGR flow to the intake manifold) for the period 2004, the compressor outlet temperature for the period 2006, the compressor inlet temperature for the period 2008, the compressor (e.g., turbocharger) speed for the period 2009, the position of the turbine wastegate for the period 2010, the position of the BTCC valve for the period 2012, the position of the medium-pressure EGR valve for the period 2014, the position of the SMBV for the period 2016, the intake valve timing for the period 2018, and the exhaust valve timing for the scavenging exhaust valves for the period 2020.In an embodiment where the purge outlet valves and blow-off outlet valves are controlled by the same cam system, the outlet valve timing control at 2020 can be the timing control of both the purge outlet valves and the blow-off outlet valves. Although the valve positions in Fig. 20 can be shown as open and closed, the valves can be adjusted to a multitude of positions between fully open and fully closed. Before time t1, the compressor inlet temperature is above the first threshold temperature T1, the compressor outlet temperature is below the second threshold temperature T2, and the compressor speed is below the threshold speed S1. Therefore, the BTCC valve is open, the medium-pressure EGR valve is closed, and the relief pipe valve is closed. The inlet and outlet valve timing is also at its standard timing (as shown by the standard line D1) for optimal fuel efficiency before time t1. At time t1, the compressor inlet temperature drops below the first threshold temperature T1, indicating that condensation may form at the compressor.The EGR demand is also relatively high at this time. Therefore, in response to the compressor inlet temperature being below the first threshold temperature T1 while the EGR demand is relatively high, the BTCC valve closes and the medium-pressure EGR valve opens. This reduces the low-pressure EGR flow to the compressor inlet, thereby reducing condensation. At time t2, the compressor inlet temperature rises above the first threshold temperature T1, so the BTCC valve opens again, and the medium-pressure EGR valve closes shortly after time t2. At time t3, the compressor outlet temperature rises above the second threshold temperature T2, while the EGR demand is at a relatively low level (e.g., lower than at time t1). In response to these conditions, the BTCC valve is modulated to reduce the EGR flow, and the SMBV is modulated accordingly to be open when the BTCC valve closes. Additionally, between time t3 and time t4, the intake valve timing is advanced and the exhaust valve timing is retarded. At time t4, in response to the compressor outlet temperature falling below the second threshold temperature T2, the BTCC valve opens and the SMBV closes, and the intake and exhaust valve timings return to their standard positions for optimal fuel efficiency. At time t5, the compressor inlet temperature again drops below the first threshold temperature T1, while the EGR demand is at a lower level (compared to the higher EGR demand level at time t1). Therefore, the exhaust valve timing is delayed immediately after time t5 to reduce the EGR flow to the compressor inlet. At time t6, the exhaust valve timing reaches its maximum delay (i.e., it cannot be delayed any further). In response to reaching this maximum level, the inlet valve timing is advanced. At time t7, the compressor inlet temperature rises above the first threshold temperature, and in response, the inlet and exhaust valve timings return to their standard timings. At time t8, the compressor speed rises above the threshold speed S1. In response to this increase in compressor speed, the BTCC valve closes and the SMBV opens. Also at time t8, the purge outlet valve timing is advanced and the turbine wastegate opens. After the turbine speed drops below the threshold speed S1 again at time t9, the BTCC valve opens, the SMBV closes, and the purge outlet valve timing reverts to its standard timing. In this way, the inlet valve timing, the purge outlet valve timing, and the position of the BTCC valve (and in some examples, the SMBV) can be coordinated in response to a compressor condition (e.g., the compressor reaching one or more operating thresholds, as described above).As shown at time t3, for example, the BTCC valve was modulated to reduce the EGR flow to a first level, and the exhaust valve timing was delayed to reduce the EGR flow to a lower, second level. At this time, the inlet valve timing was advanced to reduce the pressure ratio across the compressor. As another example of coordinating the inlet valve timing, exhaust valve timing, and BTCC valve timing, as shown at times t5 to t7, the purge exhaust valve timing was delayed, and upon reaching its maximum delay while the compressor inlet temperature was still above the first threshold temperature, the inlet valve timing was advanced.A technical effect of coordinating the inlet valve timing, the exhaust valve timing of the purge valves, and the position of the BTCC valve is to reduce the EGR flow to the compressor inlet, thereby reducing condensate formation at the compressor, reducing the compressor outlet temperature, and / or reducing the compressor speed, thus reducing compressor degradation. In another embodiment, as shown at time t1, in response to the compressor inlet temperature falling below the threshold inlet temperature, the medium-pressure EGR valve can be opened to direct exhaust gas from the purge valves to the intake manifold downstream of the compressor.One technical effect of directing exhaust gas from the scavenge outlet valves to the intake manifold downstream of the compressor in response to a compressor condition is to reduce the EGR flow to the compressor inlet, thereby reducing condensate formation at the compressor, increasing the compressor outlet temperature, and reducing the compressor speed. As a result, compressor degradation can be reduced. In yet another embodiment, as shown at times t3 and t8, the BTCC valve can be closed (or modulated between open and closed), while the SMBV is opened (or modulated) accordingly to reduce the EGR flow to the compressor inlet and instead direct the exhaust gases from the scavenge manifold to the exhaust manifold.A technical effect of reducing the gas flow from the purge exhaust manifold to the intake port upstream of the compressor in response to an internal combustion engine operating condition (such as a compressor outlet temperature above a threshold outlet temperature and / or a compressor speed above a threshold speed) and, in response to the reduction of the gas flow, increasing the gas flow from the purge manifold bypass channel, is to reduce compressor degradation, while also reducing pressures in the purge exhaust manifold, and to trap residual gases in the cylinders. Fig. 10 shows a method 1000 for operating the internal combustion engine system in an initial BTCC mode. Method 1000 can proceed from step 430 of method 400, as described above. Method 1000 begins with step 1002 by adjusting the intake cam timing of the intake valves and the exhaust cam timing of the scavenge exhaust valves and the blow-off exhaust valves for best fuel efficiency. For example, the timing of the exhaust and intake valves can be adjusted for the best achievable brake-specific fuel consumption (BSFC) under the current internal combustion engine operating conditions. In one example, this can involve adjusting the timing of the scavenge exhaust valve, the blow-off exhaust valve, and the intake valve of each cylinder at the timings shown in Fig. 3A, as described above.In some embodiments, the timing of the exhaust and intake valves can be adjusted slightly differently from the timings shown in Fig. 3A, based on the internal combustion engine speed and load. For example, the intake timing can be adjusted to full retardation at lighter engine loads and advanced when the engine is gain-limited or when there is a requirement to increase blow-through to reduce knocking. In another embodiment, the exhaust valve timing can be adjusted so that the exhaust valves open sooner than the engine speed increases. The exhaust valve timing can then be retarded when the gain decreases (e.g.,(under low internal combustion engine speed and high internal combustion engine load conditions), or when the internal combustion engine speed is high and the EGR temperature is above a threshold temperature. In procedure 1004, the process involves determining whether the internal combustion engine torque output is at a required level. The required torque level could be a driver torque demand, determined in one example based on the position of the vehicle's accelerator pedal. In another example, the control unit could determine the required torque in response to a pedal position signal received from an accelerator pedal position sensor. If the torque is not at the required level, the process proceeds to procedure 1006 to optimize the cam timing and BTCC valve position for the required torque. As an example, this could involve restricting the scavenge exhaust valve flow to increase torque output and modifying the amount of restriction based on a turbocharger compressor pumping threshold.For example, restricting the purge outlet valve flow can involve delaying the purge outlet valve cam timing to reduce the EGR flow. In yet another example, this can alternatively or additionally involve delaying the intake valve cam timing to reduce blow-through from the purge outlet valves to the intake port. Furthermore, modifying the amount of purge outlet valve flow restriction can involve decreasing the restriction amount as compressor operation (e.g., flow rate and pressure drop across the compressor) approaches the pumping threshold or pumping line. In yet another example, the procedure at 1006 can additionally or alternatively involve restricting the opening amount of the BTCC valve (e.g., closing or decreasing the opening amount). When the internal combustion engine torque output is at the required level, the method proceeds to 1008 to measure the oxygen content and pressure of gases in the purge manifold (e.g., the purge exhaust manifold 80, shown in Fig. 1A). In another embodiment, the method at 1008 may additionally or alternatively include measuring the oxygen content and pressure of gases in the exhaust line of each purge outlet valve. For example, the method at 1008 may include obtaining pressure and oxygen content measurements from one or more pressure sensors and lambda probes arranged in the purge manifold and / or the purge outlet valve lines (e.g., the pressure sensor 34, the lambda probe 36, and the lambda probes 38, shown in Fig. 1A). As described above, both exhaust gases (e.g., EGR after the cylinder is ignited by the combustion of an air-fuel mixture) and purge air (during an overlap period between the opening of the intake valve and the scavenging valve) can be expelled into the scavenging manifold from the internal combustion engine cylinders via the scavenging valves. Furthermore, each scavenging valve of each internal combustion engine cylinder can expel EGR and purge air at different times than the other cylinders (e.g., based on a set firing order of the cylinders during an internal combustion engine cycle). In the sense used here, an internal combustion engine cycle refers to a period in which each internal combustion engine cylinder fires once in the cylinder firing order.If, for example, the cylinder firing order involves firing the cylinders in the following sequence: cylinder 1, cylinder 2, cylinder 3, and then cylinder 4, then the scavenging exhaust manifold can receive four separate EGR pulses and blowthroughs from each cylinder in the cylinder firing order during each internal combustion engine cycle. Therefore, the procedure at 1010 involves estimating blowthrough (BT, e.g., the amount of unburned gases entering the scavenging manifold from the scavenging exhaust valve during an overlap period between the intake and scavenging exhaust valves of each cylinder) and EGR (e.g., combusted exhaust gases).Estimating BT and EGR can involve estimating the amount of BT and EGR expelled into the scavenging exhaust manifold for each cylinder and / or estimating the total amount of BT and EGR entering the intake manifold for all cylinders during a single internal combustion engine cycle (e.g., the total BT and EGR amount for four cylinders in a four-cylinder internal combustion engine, or for as many cylinders as have scavenging exhaust valves engaged). In a first embodiment of the method at 1010, the method at 1011 can involve estimating the BT and EGR amount based on the crankshaft angle (e.g., engine position) and the scavenging manifold pressure (e.g., based on an output from a pressure sensor in the scavenging manifold).In a second embodiment of the method at 1010, the method at 1013 may involve estimating the BT and EGR amounts based on the crankshaft angle (or a corresponding time of opening and closing of the intake valve and purge exhaust valve of each cylinder) and the oxygen content of the purge manifold (e.g., based on an output from a lambda sensor in the purge manifold or in each purge exhaust valve line). Fig. 21 shows a diagram 2100 of changes in scavenging manifold pressure and oxygen content over a single internal combustion engine cycle involving the firing of four cylinders (e.g., cylinders 1-4, shown in Fig. 21). In particular, diagram 2100 illustrates an internal combustion engine position along the x-axis in crankshaft degrees (CAD) for a complete internal combustion engine cycle (e.g., from -360 CAD to 360 CAD) with four cylinders of a representative four-cylinder internal combustion engine firing (such as the engine shown in Figs. 1A-1B). For each cylinder, the timing, lift, and duration of opening (relative to the engine position) of the intake valve (IV), scavenging valve (SV), and blow-off valve (BDV) are shown.Transcript 2102 shows the cylinder valve events for the first internal combustion engine cylinder, cylinder 1; transcript 2104 shows the cylinder valve events for the second internal combustion engine cylinder, cylinder 2; transcript 2106 shows the cylinder valve events for the third internal combustion engine cylinder, cylinder 3; and transcript 2108 shows the cylinder valve events for the fourth internal combustion engine cylinder, cylinder 4. Changes in the measured scavenging manifold pressure over the engine cycle are shown in transcript 2110, and changes in the measured scavenging manifold oxygen content are shown in transcript 2112. The measured scavenging manifold oxygen content can also represent an air-fuel ratio of the gases entering the scavenging exhaust manifold from the scavenging valves. As shown in Diagram 2100, each time a safety valve (SV) opens for one of the cylinders, there is a positive pulse in the scavenge manifold pressure and a negative pulse in the scavenge manifold oxygen content. For example, when an SV opens (e.g., at -90 CAD for cylinder 2), burnt exhaust gases are expelled into the scavenge manifold. While the same SV is open, and when an intermediate valve (IV) for the same cylinder opens (e.g., overlap period, as indicated by 2114 for cylinder 2), blow-through air is expelled into the scavenge manifold. Thus, when the SV opens, there is a rise in the scavenge manifold pressure, and the scavenge manifold oxygen content decreases due to the burnt exhaust gases entering the scavenge manifold. While the SV is open and prior to the IV opening, the scavenge manifold oxygen content represents an air-fuel ratio of the burnt exhaust gases (which may be richer). Then, the scavenge manifold oxygen content rises again when the blow-through air (e.g.,those that do not contain any burnt gases and are therefore richer in oxygen than the exhaust gases) enter the scavenging manifold. While both the SV and IV are open to each cylinder simultaneously, the oxygen content of the scavenging manifold represents an air-fuel ratio of the blow-through air, which is leaner than the combustion gases. Thus, by correlating the pulses in the scavenging manifold pressure and / or oxygen content with CAD, the pressure and / or oxygen changes due to exhaust gases and blow-through air can be determined for each cylinder and differentiated between them. By observing the size (e.g., the magnitude) of these pulses over known time periods (e.g., CAD and firing order) of the exhaust gas and blow-through air discharge into the scavenging manifold, the amount of EGR and blow-through air flowing to the intake port via the scavenging manifold can be determined for each cylinder or for each internal combustion engine cycle (e.g., by summing the pulses). As another example, estimating blow-through and / or EGR flow from the scavenging manifold oxygen content can be used to measure (via a lambda sensor) a transition between a combustion-air-fuel content of the gases (e.g., exhaust gases) discharged by each scavenging manifold (e.g., exhaust gases).The transition or change between a peak (e.g., maximum) and a trough (e.g., minimum) of the lambda sensor output for each cylinder can indicate the amount of EGR and blow-through air exiting the SV for each cylinder and flowing to the intake. For example, the transition might involve an increase in the oxygen level of the blow-through air exiting the SVs. This increase in oxygen level could be from a lower, first oxygen level (at the troughs) to a higher, second oxygen level (at the peaks).The transition between the combustion air-fuel ratio content of the exhaust gases and the leaner air-fuel ratio of the exhaust gases can be determined on a cylinder-by-cylinder basis to determine the EGR flow and purge air amount for each cylinder. Furthermore, the total amount of purge air flowing from the scavenging manifold to the intake port during a single internal combustion engine cycle can be determined based on the second oxygen level for each side valve (SV) for each cylinder. Referring again to Figure 1010 from Figure 10, the BT amount and the EGR amount can be determined in this way based on an output from a pressure sensor and / or a lambda sensor positioned in the scavenging manifold (or scavenging exhaust valve lines), which is correlated with the crankshaft angle degree (e.g., engine position). As an example, the control unit can determine the BT amount for a first cylinder based on the received output from the pressure sensor between the opening time of the first cylinder's intake valve and the closing time of the first cylinder's scavenging exhaust valve. The control unit can repeat this process for each engine cylinder and then summate all the values ​​to determine a total BT amount to the intake port for a complete engine cycle.As another example, the control unit can determine the EGR flow rate for the first cylinder based on the received output from the pressure sensor between the time the first cylinder's scavenging exhaust valve opens and the time immediately before the first cylinder's intake valve opens (e.g., the time until the intake valve opens, and thus before the BT air enters the scavenging manifold). The same process can be performed using the lambda sensor output instead of the pressure sensors. For example, the control unit can make a logical determination regarding the amount of EGR or BT in the scavenging manifold based on logical rules that are a function of the scavenging manifold pressure (or oxygen content) for the set BT or EGR period, as discussed above for each cylinder. In 1012, the procedure involves adjusting the BTCC valve (e.g., adjusting a position of the BTCC valve), the timing of the purge exhaust valve (SV), the timing of the intake valve (IV), and / or the SMBV (e.g., adjusting a position of the SMBV) based on the estimated purge and EGR flow amount (as determined in 1010), the desired purge and EGR flow amount, the charge level (e.g., boost pressure downstream of the turbocharger compressor), and the current positions and timings of each of the valves listed above. As an example, the BTCC valve may open in response to the internal combustion engine being supercharged (e.g., with the turbocharger compressor operating and resulting in MAP exceeding atmospheric pressure).As another example, if more or less EGR flow or blow-through to the intake port via the scavenging manifold and the EGR port is desired relative to the estimated levels (estimated at 1010), the controller can adjust the positions or timings of one or more of the BTCC valve, SV, IV, and SMBV to achieve the desired EGR flow and blow-through. Details of adjusting the timing of the BTCC valve, SMBV, and SV to achieve the desired EGR and blow-through flow are further described with reference to Figures 12-13. Furthermore, adjusting the valve positions and timings at 1012 can involve adjusting the valve positions and / or timings relative to each other.For example, if the BTCC valve is closed and the desired purge manifold pressure is below the currently measured purge manifold pressure, the procedure at 1012 may involve opening or increasing the amount of opening of the SMBV to reduce the purge manifold pressure. In another example of the procedure at 1012, the scavenging manifold pressure can modify the control of the BTCC valve, SMBV, and / or intake valve at certain SV timing settings. For example, the SV timing can be adjusted based on the measured scavenging manifold pressure. In one example, the procedure can involve retarding the SV timing to reduce the scavenging manifold pressure in response to a measured scavenging manifold pressure that is higher than the desired scavenging manifold pressure. The desired scavenging manifold pressure can be determined based on (e.g., as a function of) one or more of the intake manifold pressure, exhaust pressure, and / or charging conditions (e.g., whether the internal combustion engine is turbocharged or not). Furthermore, in response to adjusting the SV timing based on the measured pressure and in response to the scavenging manifold pressure, the positions of the BTCC valve and / or SMBV can be adjusted.For example, after adjusting the SV timing control, the position of the SMBV can be adjusted to maintain the scavenge manifold pressure at the desired scavenge manifold pressure (based on the internal combustion engine operating conditions), and the position of the BTCC valve can be adjusted to maintain the EGR flow at a desired EGR flow (e.g., based on internal combustion engine operating conditions such as engine load, knocking, and compressor operating conditions such as temperature and speed). The method proceeds to 1014 to close the charge motion control valves (e.g., CMCVs 24, shown in Fig. 1A) positioned in at least one intake port of each cylinder. As an example, closing the CMCVs may involve the control system actuating a valve actuator of the CMCVs to move the CMCVs into the closed position, which restricts the airflow entering the cylinder through the inlet valves of the intake ports to which the CMCVs are internally coupled. For example, the closed position may involve the CMCVs being fully open, and the valve plate of the CMCVs being fully tilted into the corresponding intake port (e.g., opening), resulting in maximum air charge flow restriction. This can reduce the short-circuiting of air from the inlet valve directly to the SV without the complete purging of exhaust gases from inside the cylinders.As a result of closing the CMCVs during operation in output BTCC mode, more exhaust scavenging can result, thereby increasing internal combustion engine power and torque output during subsequent cylinder combustion events. In procedure 1016, this involves determining whether conditions for performing a valve diagnosis are met for one or more of the BTCC valves, SMBVs, or SVs. For example, the conditions for performing the valve diagnosis might include one or more of the following: the elapsed time since a previous valve diagnosis, a period of engine operation, and / or a number of engine cycles. For instance, a valve diagnosis could be performed at regular intervals (e.g., after a set period of engine operation or a set number of engine cycles), after each shutdown event (e.g., on engine restart), or in response to a diagnostic flag set in the controller.For example, a diagnostic marker may be set if a measured scavenging manifold pressure differs from the expected value by a threshold amount, based on the current valve positions and timings of the BTCC valve, SMBV, and / or the SVs. If conditions for performing the valve diagnosis are met, the procedure proceeds to 1018 to perform the valve diagnosis and diagnose a position or timing of the BTCC valve, SMBC, and SVs based on the scavenging manifold pressure. Details of how to perform this diagnostic routine are described in more detail below with reference to Fig. 11. Alternatively, if at 1016 no conditions for performing the valve diagnosis are met, the procedure proceeds to 1020 to not perform the diagnosis and instead continue internal combustion engine operation using the current valve positions / timings. Procedure 1000 then terminates. In this way, the BTCC valve, SV timing, IV timing, and / or SMBV can be adjusted based on an estimate of the blow-through and EGR flow determined from a scavenge manifold pressure or oxygen content measurement (or estimate). As an example, one method involves adjusting the amount of opening overlap between the intake and scavenge exhaust valves (e.g., by advancing or retarding the SV and IV timing, as discussed above) in response to a transition from an estimated combustion air-fuel ratio to a leaner blow-through air ratio on a cylinder-by-cylinder basis. As explained above, for each cylinder, there can be a transition from the estimated combustion air-fuel ratio to the leaner air-fuel ratio corresponding to an SV opening event for each cylinder.One technical effect of adjusting the valve overlap in response to this transition is to deliver the desired amount of blow-through to the intake port, thereby increasing engine efficiency and reducing engine knock. Another example involves adjusting the BTCC valve, SMBV, SV timing, and / or IV timing based on the measured pressure in the scavenge exhaust manifold. A technical effect of adjusting these valves and / or valve timing based on the scavenge manifold pressure is to increase the accuracy of controlling the amount of blow-through and EGR flow to the intake port, thereby increasing engine efficiency, reducing engine emissions, and reducing engine knock. With reference to Fig. 11, a method 1100 for diagnosing one or more valves of the split exhaust internal combustion engine system based on the scavenging manifold pressure is shown. Method 1100 can proceed from 1018 of method 1000 as described above. The method begins at 1102 by determining an expected pressure drop across each of the BTCC valve and the SMBV and determining the expected timing of the scavenging outlet valves (SVs). As an example, the expected pressure drop (e.g., differential) across the BTCC valve and the SMBV can be determined based on a commanded position of the BTCC valve and the SMBV and additional internal combustion engine operating conditions. For example, the commanded position of the valves can include fully open, fully closed, or a plurality of positions between fully open and fully closed.In the case of the expected pressure loss across the BTCC valve, the additional internal combustion engine operating conditions may include pressure in the intake manifold upstream of the compressor (e.g., at the point where the EGR channel connects to the intake manifold), atmospheric pressure (e.g., if there is no electric compressor upstream of the compressor or the electric compressor is not operating), the position of the SMBV (e.g., open or closed), exhaust pressure in the exhaust manifold at the point where the scavenging manifold bypass channel connects to the exhaust manifold, and / or timing of the SVs.As an example, the controller can determine the expected pressure drop across the BTCC valve based on a lookup table stored in the controller's memory. This lookup table takes one or more of the commanded BTCC valve positions, intake pressure, atmospheric pressure, exhaust pressure, SMBV position, and SV timing as inputs, and the expected pressure drop across the BTCC valve as output. In another example, the controller can determine the expected pressure drop according to a relationship stored in the controller's memory that is a function of the commanded BTCC valve position, intake pressure, atmospheric pressure, exhaust pressure, SMBV position, and / or SV timing.Similarly, the control system can determine the expected pressure drop across the SMBV based on the commanded SMBV position and internal combustion engine operating conditions, which may include one or more BTCC valve positions, SV timing, and the exhaust pressure in the exhaust duct where the scavenge manifold bypass duct couples to the exhaust duct (e.g., using lookup tables or stored relationships, as explained above). In one example, the exhaust pressure in the exhaust duct where the scavenge manifold bypass duct couples to the exhaust duct may be a pressure measured by a pressure sensor located in the exhaust duct, such as pressure sensor 96 shown in Fig. 1A.In another example, the intake pressure, where the EGR channel couples to the intake manifold, can be measured via a pressure sensor located in the intake manifold upstream of the compressor, such as pressure sensor 31 shown in Fig. 1A. The expected timing of the safety valves (SVs) can be the currently set (or last commanded) timing of the SVs. For example, the controller can look up or determine the last commanded or output timing for the SVs and use this as the expected SV timing. In the case of 1104, the method involves determining the actual pressure losses across the BTCC valve and across the SMBV, and determining the actual timing of the SVs based on a measured pressure in the scavenging manifold. As an example, the scavenging manifold pressure can be measured via a pressure sensor located in the scavenging manifold (e.g., pressure sensor 34, shown in Fig. 1A). The controller can receive the time-varying signal from the scavenging manifold pressure sensor and then measure either an instantaneous or average scavenging manifold pressure (e.g., average over one internal combustion engine cycle or a multitude of internal combustion engine cycles).As an example, the actual pressure drop across the BTCC valve can be determined based on the output of the scavenge manifold pressure sensor and atmospheric pressure (or based on the output of a pressure sensor located in the intake manifold at the point where the EGR channel connects to the intake manifold upstream of the compressor). For example, the controller can determine the actual pressure drop across the BTCC valve based on a lookup table stored in the controller, where the measured scavenge manifold pressure and atmospheric (or intake) pressure are the inputs and the actual BTCC valve position is the output.Similarly, the control unit can determine the actual pressure drop across the SMBV based on the output of the pressure sensor located in the scavenging manifold and an output of a pressure sensor located in the exhaust duct at an outlet of the scavenging manifold bypass channel (e.g., pressure sensor 96, shown in Fig. 1A). Furthermore, the control unit can determine the actual timing (e.g., opening time) of the safety valves based on a spike in the scavenging manifold pressure output during a single engine cycle. As described above with reference to Fig. 21, for example, the pressure signal from the scavenging manifold pressure sensor can pulse (or spike) whenever a safety valve opens. The control unit can correlate this pulse with the CAD (or engine position) at which this pulse occurs and can thus determine the opening and closing times of the safety valves. The procedure then proceeds to 1106 to determine whether an absolute value of the difference between the actual pressure drop or timing, determined at 1104, and the expected pressure drop or timing, determined at 1102, exceeds a threshold difference. At 1106, the procedure may involve determining this difference for each of the BTCC valve, SMBV, and SVs. The threshold difference may be a non-zero difference and may indicate valves that are in a position or timing other than desired. For example, this difference may indicate that the BTCC valve is incorrectly positioned (e.g., open instead of closed, or closed instead of open).In another example, the difference could be one indicating that the timing of the SVs deviates from the desired (or commanded) value by a CAD threshold. These differences can lead to degraded internal combustion engine performance, such as reduced torque output, increased emissions, and / or deterioration of the turbocharger or emissions control devices. If the absolute value of the difference between the actual pressure loss or timing and the expected pressure loss or timing does not exceed a threshold difference, the procedure proceeds to 1110 to continue operating the valves at the set positions and / or timings based on the current internal combustion engine operating conditions (e.g., according to procedure 400, which was described above with reference to Figures 4A-4B). For example, if the difference between the actual pressure loss or timing and the expected pressure loss or timing does not exceed the threshold difference, the valves cannot be deteriorated and they can be in their commanded or set positions. If, alternatively, the difference between the actual pressure drop or timing and the expected pressure drop or timing in 1106 exceeds the threshold difference, the procedure proceeds to 1108 to adjust the commanded position / timing of the identified valve(s), indicate the deterioration of the identified valve(s), and / or adjust an alternative valve to deliver the desired amount of EGR and blow-through to the intake port. As introduced above, procedure 1100 can be performed for one or more, or each, of the SVs, the BTCC valve, and the SMBV.Therefore, procedure 1108 proceeds to perform the actions described above for all of the valves for which the difference between the actual pressure loss or timing and the expected pressure loss or timing exceeds the relevant threshold difference. In one example, the control may indicate deterioration of the identified valve(s) by setting a diagnostic marker and / or alerting a driver that the identified valve(s) require service or replacement (e.g., by an audible or visual signal). In another example, the control may move the identified valve(s) to the desired (e.g., originally commanded) positions or timings.For example, if it is diagnosed that the BTCC valve is mispositioned, the procedure at 1108 may involve moving the valve to the desired position (e.g., open or closed), and then the controller may repeat the diagnosis to see if the BTCC valve has moved to the desired position. In another example, if the identified valve is the SVs, the procedure at 1108 may involve further delaying the SV timing behind a desired or previously commanded level if the actual timing is further advanced than the desired timing. In this way, adjusting the valve positions or timings at 1108 may involve compensating for the difference identified at 1106 and may thus result in achieving a desired valve position or timing. In yet another example, and as below with reference to Fig.As explained in more detail in 12-13, the procedure at 1108 may involve adjusting an alternative valve, different from the identified valve (e.g., one of the non-deteriorated or correctly positioned valves), to deliver the desired EGR or blow-off flow. For example, if the BTCC valve is identified as incorrectly positioned based on the difference determined at 1106, the procedure may involve adjusting the timing of the SVs to deliver the desired EGR and blow-off flow, rather than adjusting the BTCC valve. In another example, in response to the fact that the difference between the actual pressure drop and the expected pressure drop across the BTCC exceeds the threshold difference, the EGR flow to the intake port may be adjusted to the desired level by adjusting the position of the SMBV and / or the timing of the SVs, rather than by adjusting the position of the BTCC valve.In yet another example, the control system, in response to determining that the SMBV is mispositioned, can instead adjust the BTCC valve to deliver the desired EGR flow and blow-off rate. In yet another example, the procedure at 1108 can involve adjusting the flow of exhaust gases from the SVs to the intake manifold by adjusting only the BTCC valve, rather than the timing of the SVs, in response to the actual SV opening time differing from the expected timing by a threshold value. In this way, the desired EGR and blow-off rate can still be delivered to the intake manifold even if one or more of the valves described above are malfunctioning or mispositioned. In this way, the position of one or more BTCC valves and SMBVs, and / or the timing of SVs, can be diagnosed based on an output from a pressure sensor located in the purge exhaust manifold. The valve diagnosed as deteriorated or incorrectly positioned can then be repositioned, and / or an alternative valve can be adjusted to achieve desired operating conditions (such as a desired EGR flow or pressure in the first exhaust manifold). Thus, a technical benefit of diagnosing the BTCC valve, SMBV, and / or SVs based on purge manifold pressure is to facilitate the determination of valve deterioration (e.g.,...).Determining when a valve needs servicing or replacement) and the ability to deliver the desired EGR flow or blow-through amount to the intake manifold even when one or more of these valves are mispositioned or deteriorated, by fitting an alternative valve. In this way, internal combustion engine efficiency and fuel efficiency can be maintained even if one or more valves are diagnosed as deteriorated or mispositioned. In embodiments in which a hot pipe valve or a medium-pressure EGR valve is included in the split exhaust gas combustion engine system (e.g., the hot pipe valve 32 and the medium-pressure EGR valve 59, shown in Fig. 1A), the method 1100 can further diagnose the positions of these valves in a similar manner to the diagnosis of the BTCC valve and the SMBV, as disclosed above. With reference to Fig. 12, a method 1200 for controlling the EGR flow and the blow-through air from the scavenging manifold to the intake port is shown by adjusting the operation of one or more valves of the internal combustion engine system. Method 1200 can proceed from 1012 of method 1000 or from 1108 of method 1100, as described above. For example, method 1200 can be carried out in response to changing internal combustion engine operating conditions (which may include changes in valve positions, cylinder valve timing, system pressures, etc.) that may result in a change in the desired EGR flow quantity or rate or the desired blow-through air quantity or rate from the scavenging exhaust manifold (e.g., scavenging manifold) to the intake port. Method 1200 can additionally or alternatively proceed from one or more of the other methods described here (e.g. with reference to Fig. 4A-10), which involve the modification (e.g.Describe increasing or decreasing) the EGR flow or the blow-through flow to the intake manifold. Method 1200 begins with 1202 by determining whether a request to increase EGR exists. In one example, a request to increase EGR (e.g., from the scavenging manifold 80, via the EGR channel 50, to the intake port, as shown in Fig. 1A) may exist if an estimated EGR flow rate is below a desired EGR flow rate (as described above with reference to Fig. 10). In another example, a request to increase EGR may exist after a cold start of the internal combustion engine, where the BTCC valve was closed or at least partially closed. Furthermore, a request to increase EGR may be generated in response to a turbocharger compressor outlet temperature falling below a threshold outlet temperature, a turbocharger compressor inlet temperature rising above a threshold inlet temperature, and / or a compressor speed falling below a threshold speed.If there is a requirement to increase EGR (e.g., increasing the amount of exhaust gas flow from the internal combustion engine cylinders to the intake port via the scavenging exhaust valves (SVs) and the scavenging manifold), the procedure proceeds to 1204 to adjust one or more internal combustion engine actuators to increase the EGR flow from the scavenging manifold to the intake port. Increasing EGR at 1204 may involve one or more of the opening of the BTCC valve at 1206, advancing the timing (e.g., opening and closing timing) of the SVs at 1208, and closing the SMBV at 1210. Opening the BTCC valve (e.g., valve 54, shown in Fig. 1A) can involve the controller sending a signal to an actuator of the BTCC valve to fully open the BTCC valve or to increase the degree of opening (but not full opening). Similarly, closing the SMBV (e.g., SMBV 97, shown in Fig. 1A) can involve the controller sending a signal to an actuator of the BTCC valve to fully open the BTCC valve or to increase the degree of opening (but not full opening).1A) includes the controller sending a signal to an actuator of the SMBV to close the SMBV completely or to reduce the amount it opens (but does not close completely). Furthermore, advancing the SV timing may include the controller sending a signal to an actuator of the SVs (SVs 6, shown in Fig. 1A) to advance the timing of the SVs alone or of all exhaust valves (e.g., when the SVs or BDs are controlled by the same actuator and cam timing system). The method may involve, at 1204, selecting one or more of the adjustments at 1206, 1208, and 1210 for use in increasing EGR to a desired level based on the internal combustion engine operating conditions, as described in more detail below with reference to Fig. 13. If there is no request to increase EGR at 1202, the procedure proceeds to 1212 to determine whether there is a request to decrease EGR. For example, a request to decrease EGR (e.g., from the scavenging manifold 80 via the EGR channel 50, as shown in Fig. 1A) may exist if an estimated EGR flow rate is above a desired EGR flow rate (as described above with reference to Fig. 10). For instance, in response to a turbocharger compressor condition, including one or more instances of condensation at the compressor, a compressor inlet temperature below a lower threshold temperature, a compressor outlet temperature above an upper threshold temperature, and a compressor speed above a threshold speed, a request to decrease the EGR flow to the intake port upstream of the compressor may exist.If there is a requirement to reduce EGR (e.g., to reduce the amount of exhaust gas flow from the internal combustion engine cylinders to the intake port via the scavenge exhaust valves (SVs) and the scavenge manifold), the procedure proceeds to 1214 to adjust one or more internal combustion engine actuators to reduce the EGR flow from the scavenge manifold to the intake port. Reducing EGR at 1214 may involve one or more of the closing (or reducing the opening amount) of the BTCC valve at 1216, delaying the timing (e.g., opening and closing timing) of the SVs at 1218, and opening (or increasing the opening amount) of the SMBV at 1220. The method may involve selecting one or more of the adjustments at 1216, 1218 and 1220 for use in reducing EGR to a desired level based on the internal combustion engine operating conditions, as shown below with reference to Fig.13 described in more detail. If there is no EGR reduction requirement, the procedure proceeds to 1222 to determine if there is a blow-through (BT) requirement. As described above, blow-through can involve increasing the amount of fresh, unburned air (or mixed intake air from the intake manifold, with at least a portion of the mixed intake air not undergoing combustion) that flows from the intake port to a SV during an intake valve and SV valve overlap period, and then through the scavenge manifold and EGR duct to the intake port. In one example, a blow-through requirement might be in response to a compressor outlet temperature exceeding a threshold outlet temperature, internal combustion engine knock, and / or compressor pumping.If there is a requirement to increase the blow-through rate, the procedure proceeds to 1224 to increase the blow-through rate by one or more of the delays in the timing of the SVs at 1226, the advances in the timing of the intake valves (IVs) at 1228, and the closing of the SMBV and / or the opening of the BTCC valve at 1230. For example, increasing the amount of opening overlap between the SV and the IV of the same cylinder (e.g., increasing the amount of time that both the SV and the IV of the same cylinder are open simultaneously) can lead to an increase in the amount of blow-through rate to the intake. In particular, increasing the amount of the opening overlap between the IV and the SV may involve delaying the SV time control (e.g. delaying the closing time of the SV) and / or advancing the IV time control (e.g. advancing the opening time of the IV).In one example, increasing the amount of opening (or full opening) of the BTCC valve and / or decreasing the amount of opening (or full closing) of the SMBV can increase the amount of blow-through air flowing from the internal combustion engine cylinders to the intake port. However, if the BTCC valve is already full opening and the SMBV is already full closing, the procedure at 1224 can involve retarding the SV timing and / or advancing the IV timing. Furthermore, if the SV timing is already at its maximum retard value, the procedure at 1224 can involve advancing the IV timing to increase blow-through to the intake. Similarly, the procedure at 1224 can involve retarding the SV timing to increase blow-through if the intake valve timing is already at its maximum advance.Furthermore, the procedure at 1224 may involve first delaying the SV timing and then advancing the IV timing if the blow-off rate is still not at the requested level when the SV timing reaches its maximum delay. In yet another example, the decision regarding adjusting more than one of the internal combustion engine actuators at 1224 may be based on the amount of the requested change in the blow-off rate. For example, if the requested blow-off rate continues to increase above the current level, the procedure at 1224 may involve increasing the amount of adjustment to the SV timing, IV timing, and valve position, and / or adjusting two or more of the actuators at 1224 (e.g., simultaneously delaying the SV timing and advancing the IV timing to achieve the desired blow-off rate).In this way, increasing the airflow at 1224 can involve adjusting one or more of the SV timer, IV timer, SMBV and BTCC valves based on their current timers and positions relative to each other and the amount of the requested increase in airflow. If there is no request to increase the blow-through rate, the procedure proceeds to 1232 to determine if there is a request to decrease the blow-through rate. In an example, a request to decrease the blow-through rate might be in response to a turbine operating below a threshold speed and above a threshold load, and a compressor flow rate above a threshold flow rate (where the threshold flow rate could be a flow rate at which compressor efficiency decreases and charge air heats up). If a request to decrease the blow-through rate is present, the procedure proceeds to 1234 to decrease the blow-through rate by one or more of the SV timing advance at 1236, the IV timing retard at 1238, and the SMBV opening and / or BTCC closing at 1240.For example, reducing the amount of opening overlap between the SV and IV of the same cylinder (e.g., reducing the amount of time both the SV and IV of the same cylinder are open simultaneously) can lead to a reduction in the amount of blow-through air to the intake. Specifically, reducing the amount of opening overlap between the IV and SV can involve advancing the SV timing (e.g., advancing the SV closing point) and / or retarding the IV timing (e.g., advancing the IV opening point). In one example, reducing the amount of opening (or complete closing) of the BTCC valve and / or increasing the amount of opening (or complete opening) of the SMBV can decrease the amount of blow-through air flowing from the internal combustion engine cylinders to the intake manifold.However, if the BTCC valve must remain open to deliver the requested amount of EGR to the intake port, the procedure at 1234 may involve advancing the SV timing and / or retarding the IV timing. Furthermore, if the SV timing is already at its maximum advance rate, the procedure at 1234 may involve retarding the IV timing to reduce intake blow-through. Similarly, the procedure at 1234 may involve advancing the SV timing to reduce blow-through if the intake valve timing is already at its maximum retard. Additionally, if the blow-through is still not at the requested level when the SV timing reaches its maximum advance rate, the procedure at 1234 may involve first advancing the SV timing and then retarding the IV timing.In yet another example, the decision regarding adjustment of more than one of the internal combustion engine actuators at 1234 can be based on the amount of the requested change in the amount of blow-off. For example, if the requested blow-off decreases further below the current level, the procedure at 1234 can involve reducing the amount of the SV timing adjustment and the IV timing adjustment, or adjusting both the SV timing and the IV timing simultaneously to achieve the desired blow-off amount. If there is no requirement to reduce the airflow, the procedure proceeds to 1242 to maintain the current valve positions and timings. Procedure 1200 then terminates. Fig. 13 shows a method 1300 for selecting between operating modes for adjusting the flow of exhaust gases (e.g., EGR flow) from the internal combustion engine cylinders to the intake manifold via the scavenging exhaust valves and the scavenging exhaust manifold. Method 1300 can proceed from steps 1204 and 1214 of method 1200, as described above. Method 1300 begins with step 1302 by determining whether conditions for a first mode are met. In one embodiment, conditions for a first mode for adjusting the EGR flow may include when a requested change in the EGR flow to the intake is above a threshold level. The threshold level may be a non-zero threshold value of the EGR flow that cannot be reached by adjusting only a single actuator.In another embodiment, conditions for a first mode for adjusting the EGR flow to the intake may include when neither the BTCC valve nor the SVs are diagnosed as incorrectly positioned or deteriorated (such as during procedure 1100, as described above with reference to Fig. 11). If the conditions for a first mode at 1302 are met, the procedure proceeds to 1304 to adjust both the BTCC valve and the SV timing to adjust the amount of EGR flow to the intake port. For example, the procedure at 1304 may involve simultaneously adjusting, at the same time, the position of the BTCC valve and the timing of the SVs to adjust the EGR flow to the desired level (e.g., to increase or decrease the EGR flow, as described above with reference to Fig. 12).In another example, the procedure at 1304 can involve first adjusting one of the BTCC valve position and the SV timing, and then, immediately after adjusting the first actuator, adjusting the other BTCC valve position and SV timing. In this way, adjusting the BTCC valve (e.g., opening) can modify the EGR flow by a first amount (e.g., increasing or decreasing it), and adjusting the SV timing (e.g., advancing or retarding it) can modify the EGR flow by a second amount. Thus, by adjusting both the BTCC valve position and the SV timing during the first mode, a greater adjustment of the EGR flow can be achieved. If, alternatively, the conditions of the first mode are not met in 1302, the procedure proceeds to 1306 to determine whether conditions for a second mode for adjusting the EGR flow are met. In one embodiment, the conditions for a second mode may include one or more of the following: if the timing of the SVs cannot be further adjusted for a currently required direction of EGR flow adjustment, and if the BTCC valve is in a partially open position and there is a requirement for both increased EGR flow and increased blow-through air from the SVs to the intake manifold. For example, the SV timing cannot be further adjusted if it is already at its maximum amount of retardation (in the case of decreasing EGR flow) or advance (in the case of increasing EGR flow).In another embodiment, the conditions for a second mode may additionally or alternatively include when the difference between the actual timing of the SVs and their expected timing exceeds a threshold (as explained, for example, in B above with respect to method 1100 from Fig. 11). If the SVs are diagnosed as not being at the correct timing or as deteriorated, they cannot be used to adjust the EGR flow. In this case, the BTCC valve can be adjusted to adapt the EGR flow to the desired level based on the actual timing of the SVs. If the conditions for a second mode at 1306 are met, the method proceeds to 1308 to adjust only the BTCC valve to adjust the EGR flow to the desired level. For example, the method at 1308 may involve exclusively adjusting the position of the BTCC valve (e.g.,Increasing or decreasing the amount of opening or modulating the position between fully open and fully closed) to adjust the EGR flow to the desired level, and does not include adjusting the SV timing control. If, alternatively, the conditions of the second mode are not met in 1306, the procedure proceeds to 1310 to determine whether conditions for a third mode for adjusting the EGR flow are met. In one embodiment, the conditions for a third mode may include when the BTCC valve is already in a fully open position and in response to a request to increase the exhaust flow from the SVs to the intake manifold. In another embodiment, the conditions for a third mode may additionally or alternatively include when the difference between the actual pressure drop across the BTCC valve and the expected pressure drop across the BTCC valve exceeds a threshold value (as, for example, explained above with respect to procedure 1100 from Fig. 11). Thus, if the BTCC valve is diagnosed as incorrectly positioned or deteriorated, it cannot be used to adjust the EGR flow.If the conditions for a third mode at 1310 are met, the procedure proceeds to 1312 to adjust only the SV timing to adjust the EGR flow. For example, the procedure at 1312 may involve advancing or retarding the SV timing to adjust the EGR flow to the desired level, without adjusting the BTCC valve. If, for example, the BTCC valve is already fully open and there is a requirement to increase the EGR flow, the procedure at 1312 involves keeping the BTCC valve in a fully open position and adjusting the SV timing to adjust the EGR flow to the desired level. If the conditions for a third mode are not met at 1310, the procedure proceeds to 1314 to maintain the SV timing and BTCC valve position at their current timings / positions. Procedure 1300 then terminates. Fig. 22 shows a diagram 2200 of the control of one or more internal combustion engine actuators to adjust the EGR flow and the blow-through flow from the scavenging outlet valves to the intake manifold.In particular, diagram 2200 shows changes in EGR flow at curve 2202, changes in the blow-through amount (BT) at curve 2204, changes in the position of the BTCC valve at curve 2206, changes in the SV timing at curve 2208 (relative to a standard timing D1 for best fuel efficiency, a maximum amount of advance MA and a maximum amount of delay MR), changes in the position of the SMBV at curve 2210, changes in the IV timing at curve 2212 (relative to a standard timing D2 for best fuel efficiency, a maximum amount of advance MA and a maximum amount of delay MR), changes in the difference between an actual pressure drop and an expected pressure drop across the BTCC valve (e.g. during valve diagnostics) at curve 2214 and changes in the difference between an actual timing and an expected timing of the SVs at curve 2216. At time t1, the BTCC valve is fully open, the SMBV is fully closed, the IV timing is at its default time D2, and the SV timing is at its default time D1. At time t1, there may be a request to increase the EGR flow to the intake manifold to a first level. In response to this request, and because the BTCC valve is already in the fully open position, the SV timing is advanced to increase the EGR flow to the first level. Advancing the SV timing may also decrease the BT. Thus, at time t2, there is a request to increase the BT. However, since the EGR flow request is still at the first level, the intake valve timing is advanced at t2, while the SV timing remains at the advanced time. Before time t3, the difference between the actual and expected timing of the valve timing increases above a threshold value T2. At time t3, a request to reduce the EGR flow and blow-off rate may then be present. Therefore, in response to this request and the diagnosis of the valve timing at time t3, the BTCC valve closes to reduce the EGR flow and blow-off rate. With the BTCC valve closed, the intake valve timing can revert to the standard timing D2. Between time t3 and time t4, the position of the BTCC valve can be modulated between fully open and fully closed to achieve the desired EGR flow to the intake.In alternative embodiments where the BTCC valve is a continuously variable valve that can be adjusted to a multitude of positions, including fully open and fully closed, the BTCC valve can be adjusted to a partially closed position and held there, delivering the desired EGR flow to the inlet (e.g., instead of modulating). Before time t4, the difference between the actual and expected SV timing may decrease back below the threshold value T2. At time t4, there may again be a request to increase the EGR, but to a second level that is higher than the first level requested at time t1. In response to this higher request, which may exceed a threshold increase in the EGR flow, the BTCC valve opens at time t4, and the SV timing is advanced.The IV timing can also be advanced at time t4 to maintain the BT at the desired level. This allows both the BTCC valve and the SV timing to be adjusted simultaneously to adapt the EGR flow to the requested second level. At time t5, a request to reduce the EGR flow may be present. Immediately before time t5, the difference between the actual and expected pressure drop across the BTCC valve may increase beyond a threshold value T1. In response to the BTCC valve's request and diagnosis, the SV timing control is delayed. However, at time t6, the SV timing control may reach its maximum delay, but the EGR flow may still need to be reduced further. As a result, the SMBV may open to further reduce the EGR flow to the intake manifold. In this way, under different operating modes, one or more actuators (e.g., the BTCC valve, the SV timing control, the IV timing control, and / or the SMBV) can be adjusted to achieve the desired EGR and BT flow rates.For example, during a first mode, as shown at time t4, both the SV timing and the BTCC valve are adjusted to deliver the desired EGR flow to the intake manifold. As another example, during a second mode, as shown at time t3, only the BTCC valve is adjusted to deliver the desired EGR flow, as the SVs are diagnosed as not being at the correct timing (and possibly exhibiting degraded function). At this time, however, the IV timing is also adjusted to maintain the desired BT flow. Furthermore, during a third mode, as shown at time t5, only the SV timing is adjusted to adjust the EGR flow, as the BTCC valve is diagnosed as exhibiting degraded function and / or being incorrectly positioned.Since the SV timing control reaches its maximum delay at time t6, the SMBV is opened in addition to delaying the SV timing control to achieve the higher desired EGR level. Adjusting the various actuators in coordination with each other (e.g., based on the current position, timing, and / or deterioration or incorrect position of another actuator) can enable the efficient delivery of both the desired EGR and BT current via the SVs to the intake manifold.A technical benefit of adjusting the exhaust gas flow from the scavenge valves to the intake port upstream of the compressor by adjusting one or both of the BTCC valve and the scavenge valve timing in the different modes described above is that the desired EGR flow and blow-through flow can be delivered to the intake, even when one of the BTCC valves or the SV timing cannot be adjusted. Furthermore, controlling the EGR flow in the third mode by adjusting only the SV timing can provide a more consistent EGR flow, with a fixed amount of EGR being forced to the intake port in each engine cycle. For example, controlling the EGR flow in this way can allow the EGR valve to be an on / off valve, simplifying EGR valve control and reducing engine system costs. Fig. 14 shows a method 1400 for operating the vehicle in electric mode (e.g., all-electric mode). Method 1400 can proceed from step 405 of method 400 as described above. Method 1400 begins with step 1402 by driving the hybrid electric vehicle exclusively by means of engine torque. For example, one or more clutches can be moved to disengage the crankshaft of the internal combustion engine from an electric machine and its associated components and to connect the electric machine to the transmission and wheels of the vehicle (such as the electric machine 161, the transmission 167, and the clutches 166, shown in Fig. 1B). In this way, the electric machine (e.g., motor) can provide torque to the vehicle wheels (e.g., using electrical power received from a traction battery). In procedure 1404, this involves determining whether an internal combustion engine start is imminent. For example, the controller can determine, in response to the battery charge status and the driver's torque demand, that an internal combustion engine start is imminent (e.g., the engine needs to be started to begin combustion and provide torque to propel the vehicle). If, for instance, the required torque cannot be provided by the battery (at its current charge level), a request can be generated to start the internal combustion engine and operate the vehicle in internal combustion engine mode. In another example, if the required torque can only be provided by the battery for a limited period, a request can be generated to start the internal combustion engine within that limited period.This period may be based on a time quantity for increasing the intake manifold pressure and / or piston temperature above threshold levels for starting the internal combustion engine with reduced emissions, as described in more detail below. However, if the required torque can only be provided by the battery (e.g., for longer than the limited period) and thus an internal combustion engine start is not imminent, the procedure may proceed to 1406 to determine whether the vehicle is decelerating. In one example, the vehicle may decelerate when an accelerator pedal is released and / or a brake pedal is applied. In another example, the vehicle may decelerate when the internal combustion engine speed decreases. If the vehicle does not decelerate, the procedure proceeds to 1407 to continue propelling the vehicle solely by engine torque.However, if the control system determines that the vehicle is slowing down, the procedure proceeds to 1408 to shut off all the blow-off exhaust valves (e.g., the first exhaust valves 8, shown in Fig. 1A) of the internal combustion engine cylinders and rotate the internal combustion engine using torque from the vehicle wheels (via the crankshaft) instead of charging the battery. In one example, shutting off all the blow-off exhaust valves might involve the control system shutting off one or more of the blow-off exhaust valve actuation systems to keep the blow-off exhaust valves closed so that no gases move through the cylinders into the exhaust port. As a consequence, no gases can move through the exhaust port, thereby reducing internal combustion engine emissions. The rotation (e.g.,Rotating the internal combustion engine during deceleration can lead to the warming up of the internal combustion engine, thereby increasing engine power and reducing engine emissions during engine start-up. Referring to Fig. 1404, when an internal combustion engine start is imminent, the method proceeds to 1410 to determine whether to operate in a blow-off valve shutdown mode before the engine start (e.g., before ignition of the engine). In one embodiment, the control unit can determine that the internal combustion engine should operate in the blow-off shutdown mode in response to an intake manifold pressure exceeding a threshold pressure. The threshold pressure can be based on an intake manifold pressure at which increased emissions may occur during engine start. In one example, the threshold pressure can be at or above atmospheric pressure.In another embodiment, the control system can determine whether to operate the internal combustion engine in blow-off mode or in an extended crankshaft mode in response to a piston temperature below a threshold temperature. The threshold temperature can be the temperature at which the engine restarts with reduced emissions. For example, if the engine restarts with a piston temperature below the threshold temperature, increased emissions may result. In one example, the decision to operate in blow-off mode or extended crankshaft mode can be determined based on a threshold cylinder (or piston) temperature at which fuel vaporization occurs. Thus, the decision at 1410 can also be based on the fuel type.If the piston (or cylinder) temperature is below the threshold temperature, which is the temperature required to vaporize the current type of fuel, the control system may determine that the internal combustion engine will operate in extended crankshaft mode at 1410. When the blow-off valve shutdown mode is selected at 1410, the procedure proceeds to 1412 to shut off all blow-off exhaust valves before the internal combustion engine is cranked (e.g., shutting off the blow-off exhaust valve 8 of each cylinder, as shown in Fig. 1A). As a result, no gases passing through the internal combustion engine cylinders can flow to the exhaust manifold. At 1414, the procedure involves circulating gases through the internal combustion engine cylinders and back to the turbocharger compressor inlet (e.g., compressor 162, shown in Fig. 1A) via the scavenging exhaust manifold (e.g., the second exhaust manifold 80, shown in Fig. 1A) and the scavenging exhaust valves (e.g., the scavenging exhaust valves 6, shown in Fig. 1A) to pump down the intake manifold pressure.In this way, gases can enter the internal combustion engine cylinders via the intake manifold, exit the cylinders through each cylinder's scavenging exhaust valves, and then flow into the scavenging exhaust manifold, through the EGR channel to the intake manifold, and back to the intake manifold. This can be repeated for several crankshaft rotations. For example, the procedure can be repeated at 1414 until the manifold pressure drops below a lower threshold pressure or until an indication is received that the internal combustion engine needs to be started. When it is decided at 1416 that it is time to start the internal combustion engine (e.g.,Based on the intake manifold pressure decreasing below the lower threshold pressure for internal combustion engine starting, and / or based on the fact that the torque demand can no longer be supplied by the battery, the method proceeds to 1418 to determine whether a catalyst located in the exhaust duct (e.g., the emission control device 70 and / or 72, shown in Fig. 1A) is at a starting temperature. If the catalyst is not at the starting temperature, the method proceeds to 1420 to re-enable the blow-off valves of the inner cylinders while the blow-off valves of the outer cylinders remain closed, and the cylinders are fired. As an example, the inner cylinders may include the cylinder within which and between the outer cylinders of the internal combustion engine is oriented (as shown in Fig. 1A).As shown in Figure 1A, cylinders 14 and 16 are inner cylinders, and cylinders 12 and 18 are outer cylinders. This can help the catalyst(s) reach its start-up temperature(s) more quickly. Alternatively, if the catalyst is at start-up temperature at step 1418, the procedure proceeds to step 1422 to re-open all the blow-off valves of all cylinders, inject fuel into each cylinder, and resume combustion in each cylinder. As a result, the vehicle can begin operating in internal combustion engine mode (e.g., pure internal combustion engine or auxiliary mode) and stop operating in pure electric mode. Referring again to 1410, where it is determined that the internal combustion engine should be operated in the extended crankshaft mode instead of the blow-off valve mode, the method transitions from 1410 to 1424. In 1424, the method involves operating in the extended crankshaft mode by slowly rotating the unfueled internal combustion engine using the engine (e.g., an electric motor). The method in 1424 may further involve heating each cylinder during a compressor stroke of the cylinder. For example, in 1424, while propelling the hybrid vehicle solely by engine torque and prior to restarting the internal combustion engine, the method may involve rotating the unfueled internal combustion engine using the engine torque at less than a threshold speed. Here, the vehicle's electric motor can propel the vehicle and rotate the internal combustion engine.The threshold speed could, for example, be the crankshaft speed of an internal combustion engine. This means the engine can be rotated at a speed lower than the speed at which it would be turned by a starter motor during cranking and restarting. For example, the engine might be rotated at 150 rpm by a starter motor while cranking without fuel supply. In contrast, the engine might be rotated at 10-30 rpm by the electric motor / generator of a hybrid vehicle during slow cylinder heating. In alternative examples, the threshold speed at or below which the engine rotates slowly could be higher or lower based on operating parameters such as oil temperature, ambient temperature, or NVH (noise, vibration, and harshness).In one example, the slow rotation of the internal combustion engine can be initiated in a cylinder (e.g., a first cylinder) selected based on its proximity to a cylinder piston position relative to a compression stroke top dead center (TDC). For instance, a control system can identify a cylinder with a piston positioned closest to the compression stroke TDC or at a position where at least a threshold level of compression is experienced. The engine is then rotated so that each cylinder is heated sequentially during its compression stroke. As the rotation progresses, each cylinder can be cooled during its power stroke, which immediately follows the compression stroke.However, the cylinder can be heated more during the compression stroke than it is cooled during the power stroke, resulting in a net heating of each cylinder via a heat pump effect. Therefore, during each cylinder's compression stroke, air is compressed, generating heat. By rotating an internal combustion engine so that a cylinder remains in the compression stroke, heat from the compressed air can be transferred to the cylinder walls, cylinder head, and piston, thus raising the engine temperature. Referring to 1426, the method involves throttling the BTCC valve (e.g., the first EGR valve 54, shown in Fig. 1A) or the hot pipe valve (e.g., the third valve 32, shown in Fig. 1A) to increase cranking torque and, as a result, to further heat the internal combustion engine. In one example, throttling the BTCC valve or the hot pipe valve may involve at least partially closing (or reducing the degree of opening) the BTCC valve or the hot pipe valve. In some examples, the intake throttle and the BTCC valve in 1426 may be closed to recirculate gases through the cylinders via the hot pipe (rather than the EGR channel), while the hot pipe valve is partially closed (e.g., throttled) to increase cranking torque.In another example, the intake throttle can remain open and the hot pipe valve can be fully closed to recirculate gases through the cylinders via the EGR channel (e.g., the first EGR channel 50, shown in Fig. 1A), while the BTCC valve is partially closed (e.g., throttled) to increase crank torque. At 1428, the procedure involves determining whether it is time to start (e.g., restart) the internal combustion engine. In one example, the internal combustion engine cannot be started until the piston temperature rises above the threshold temperature. If it is not time to start the internal combustion engine, the procedure returns to 1424 and 1426 to continue operation in extended crankshaft mode. If, otherwise, it is time to start the internal combustion engine, the procedure proceeds to 1422 to restart the internal combustion engine as described above. Fig. 23 shows a diagram 2300 for operating the hybrid electric vehicle in electric mode to heat the internal combustion engine system before starting the internal combustion engine. In particular, diagram 2300 shows the vehicle speed at curve 2302, the battery charge status (state of charge - SOC) at curve 2304, the manifold absolute pressure (MAP) at curve 2306, the piston temperature at curve 2308, the catalyst temperature at curve 2310, the internal combustion engine speed at curve 2312, the activation state of the cylinder blow-off valve (BDV) at curve 2314, the position of the BTCC valve (e.g., the first EGR valve 54, shown in Fig. 1A) at curve 2316, the position of the hot pipe valve (e.g., valve 32, shown in Fig. 1A) at curve 2318, and the position of an intake throttle (e.g., throttle 62, shown in Fig. 1A) at curve 2320. All curves are shown against time along the x-axis. Before time t1, the vehicle may be operating in electric mode and powered solely by engine torque. For example, the internal combustion engine starting conditions may not be met before time t1. Between times t1 and t2, when operator torque demand and, consequently, vehicle speed vary, the battery state of charge (SOC) may fluctuate, decreasing at a higher rate as vehicle speed increases. While the vehicle is powered by engine torque between times t1 and t2, the piston temperature may be below the threshold temperature T1, and the manifold absolute pressure (MAP) may be above the threshold pressure P1. At time t2, the operator torque demand and vehicle speed increase. As a result, the battery state of charge (SOC) may stop decreasing or decrease at a slower rate. Shortly after time t2, a vehicle deceleration event occurs. During this event, instead of dissipating wheel torque as heat or using it to recharge the battery, the internal combustion engine is opportunistically rotated via the wheels without fuel supply, and the exhaust valves of all engine cylinders are shut off. For example, at least some of the wheel torque is applied to the engine rotation via the vehicle's motor / generator, with a temporary increase in the engine's rotational speed.As a result of the internal combustion engine's rotation and the deactivation of the blow-off valves, air is recirculated through the engine via the scavenging exhaust valves, the EGR channel, and the open BTCC valve, thereby increasing the piston temperature. Once the vehicle speed decreases, the opportunistic engine rotation ceases. In alternative embodiments, in an internal combustion engine system with a hot pipe (e.g., the hot pipe 30, shown in Fig. 1A) coupled between the scavenging exhaust manifold and the intake manifold downstream of an intake throttle, the intake throttle and the BTCC valve can be closed, while a valve in the hot pipe is opened to allow the recirculation of air through the engine cylinders via the scavenging exhaust valves and the hot pipe. At time t3, the deceleration event ends and the vehicle speed increases again. At time t4, there may be an indication that an engine start is imminent. In response to the fact that, during the indication of the imminent engine start, the MAP (Magnetic Output Pressure) is above the threshold pressure P1 and the piston temperature is below the threshold temperature T1, all BDVs (Battery Valves) of all engine cylinders are deactivated again. While the BTCC (Battery Combustion Chamber Valve) is open, gases are circulated through the engine cylinders and back to the intake manifold via the scavenging exhaust valves, the scavenging exhaust manifold, and the EGR (Exhaust Gas Recirculation) channel. As a result, the intake manifold pressure decreases. At time t5, the intake manifold pressure decreases below the threshold pressure P1. As a result, the engine can be started.However, since the catalyst temperature is below the start-up temperature T2, only the combustion air injection systems (CAES) of the inner cylinders can be reactivated, while the CAES of the outer cylinders remain deactivated. Then, when the catalyst temperature rises above the start-up temperature T2 at time t6, the CAES of the outer cylinders are reactivated. After a period of time (e.g., after an internal combustion engine shutdown and / or the vehicle being switched off by the ignition key), the vehicle can resume operation in electric mode and be driven entirely by engine torque. At time t7, there may be an indication that an internal combustion engine start is imminent while the piston temperature is below the threshold temperature T1. In response, the vehicle may operate in an extended crankshaft mode, with the internal combustion engine slowly rotating without fuel supply via the electric motor (e.g., at less than one crankshaft speed). During the internal combustion engine's rotation, the BTCC valve may be closed, the hot pipe valve at least partially open, and the intake throttle closed.Furthermore, the hot pipe valve cannot be fully open (so it is partially throttled) to increase crankshaft torque and further increase the heating of the internal combustion engine. As a result of this process, air is heated in the cylinders during the compression stroke and then recirculated through the engine system via the scavenging exhaust valves, the scavenging exhaust manifold, the hot pipe, and the intake manifold, thereby increasing the piston temperature. At time t8, the piston temperature rises above the threshold temperature T1. As a result, the engine restarts, and the BTCC valve and intake throttle open, while the hot pipe valve closes. In this way, the internal combustion engine of a hybrid vehicle can be slowly cranked during a transition from electric to combustion mode to preheat the engine before starting. Slowly turning the non-fueled engine for a period before starting allows heat generated by air being compressed in a cylinder during a compression stroke to be transferred to the cylinder walls and piston, advantageously used to preheat the engine. Furthermore, throttling the hot pipe valve (or the BTCC valve if gases are recirculated via the EGR channel instead of the hot pipe) increases cranking torque, further enhancing the preheating of the engine.Thus, a technical effect of rotating the unfueled internal combustion engine via engine torque at less than one crankshaft speed while at least partially throttling the BTCC valve or the hot pipe valve is to increase the piston temperature and the temperature of the rest of the engine, thereby reducing cold-start emissions and allowing the engine to start faster. In another example, by disabling the blow-off valves and recirculating air through the engine cylinders, the scavenging exhaust manifold, and the EGR channel, the intake manifold pressure can be reduced and / or the engine temperature can be increased. This allows the engine to start faster and improves overall cold-start emissions and engine performance.Thus, a technical effect of switching off the blow-off valves and circulating air through the internal combustion engine cylinders during electric mode is to reduce the intake manifold pressure, increase the internal combustion engine temperature and thus start the internal combustion engine faster, while reducing emissions. Fig. 15 shows a method for operating the internal combustion engine system in a shutdown mode. Method 1500 can proceed from step 426 of Method 400 as described above. Method 1500 begins with step 1502 by determining whether the detected or indicated shutdown event is an ignition key off shutdown. In one example, in response to the controller receiving a signal that an ignition (operated by a user) has been turned off, it can be determined that this is an ignition key off shutdown event. In another example, in response to the controller receiving a signal that the internal combustion engine has been turned off (e.g., via an ignition that has been turned off) and the vehicle has been positioned in park mode, it can be determined that this is an ignition key off shutdown event.In this way, an ignition key off shutdown can be a shutdown during which the internal combustion engine is expected to be switched off for a threshold period and not restarted for a duration. If the shutdown at 1502 is an ignition key off shutdown, the procedure proceeds to 1504 to close the intake throttle (e.g., throttle 62, shown in Fig. 1A) and open the hot tube valve (e.g., valve 32, shown in Fig. 1A) to pump unburned hydrocarbons to a catalyst (e.g., one of the emission control devices 70 and 72, shown in Fig. 1A) in the exhaust port of the internal combustion engine. During this time, the blow-off exhaust valves remain closed. Furthermore, the procedure at 1504 may also include, during the closing of the intake throttle and the opening of the hot tube valve, the closing of the BTCC valve (e.g., the valve 54 shown in Fig. 1A).As a result, unburned hydrocarbons can be recirculated from the internal combustion engine cylinders back to the intake manifold via the scavenging exhaust valves, the scavenging exhaust manifold, and the hot pipe (e.g., channel 30, shown in Fig. 1A). The recirculated unburned hydrocarbons can then be pumped from the internal combustion engine cylinders to the exhaust manifold containing the catalyst via the blow-off valves. This can reduce the amount of hydrocarbons in the internal combustion engine during shutdown and can help maintain the catalyst at stoichiometric pressure during shutdown and subsequent restart. In 1506, the procedure involves opening the BTCC valve and the throttle when the internal combustion engine stops rotating. For example, in response to the internal combustion engine's crankshaft stopping rotating, the control unit can actuate a BTCC valve actuator to open the BTCC valve and a throttle actuator to open the throttle. This can reduce the amount of exhaust gas drawn back into the internal combustion engine's intake (e.g., intake manifold). Furthermore, in 1506, the procedure can involve first opening the BTCC valve and then, in response to the BTCC valve opening, opening the throttle. Referring again to 1502, if the shutdown is not an ignition key-off shutdown, the method may determine that the shutdown is a start / stop shutdown and may thus proceed to 1508. As an example, in response to the vehicle being stopped for a threshold period but not switched off by the ignition key (e.g., when the vehicle is stopped at a traffic light), the control unit may determine that the shutdown is a start / stop shutdown request. At 1508, the method involves initiating the start / stop shutdown. The method then proceeds to 1510 to deactivate (e.g., switch off) all blow-off exhaust valves (e.g., valves 8, shown in Fig. 1A) of the internal combustion engine and to open the BTCC valve after the last cylinder of all internal combustion engine cylinders has been fired.In other words, as soon as the last cylinder fires (e.g., the last cylinder to undergo combustion before no further cylinders fire and the engine shuts down), the control unit can deactivate the blow-off valve actuators so that the blow-off valves remain closed and no gases are released into the exhaust manifold. As a result, gases from all engine cylinders are recirculated to the intake manifold via the scavenging valves and the EGR channel. This reduces the pressure in the intake manifold during engine deceleration (e.g., as the crankshaft speed decreases and eventually stops). In procedure 1512, the process involves determining whether a restart request for the internal combustion engine exists. For example, the restart request might be generated in response to an increase in torque demand from a stationary vehicle position. For instance, releasing the brake pedal and / or pressing the accelerator pedal might generate a restart request. If a restart request exists, the process proceeds to procedure 1516 to disable the blow-off valves and hold the BTCC valve in the open position. Otherwise, if a restart request exists, the process proceeds to procedure 1514 to re-enable the blow-off valves upon an initial crankshaft rotation. Regular engine operation then resumes.The procedure can, for example, end and / or revert to procedure 400. As explained above, restarting the blow-off valves can involve the controller sending a signal to the blow-off valve actuators to resume opening and closing the blow-off valves according to their set time schedule. Fig. 24 shows a diagram 2400 for operating the vehicle's split exhaust combustion engine system in shutdown mode. Specifically, diagram 2400 shows whether the vehicle's ignition is on or off (graph 2402), the vehicle speed (graph 2404), the throttle position (graph 2406), the BTCC valve position (graph 2408), the hot pipe valve position (graph 2410), the engine speed (graph 2412), and the on / off state (e.g., on / off or activated / deactivated) of the blow-off valves (BDVs) (graph 2414). All graphs are plotted against time along the x-axis. Before time t1, the internal combustion engine is running and the vehicle speed is above a steady state (e.g., a level at which the vehicle can be stationary or not moving). Furthermore, before time t1, all boost pressure control valves (BPVs) of all engine cylinders are switched on and operating at their set timing (which differs from the opening time of the scavenging exhaust valves). After time t1, the vehicle speed decreases to approximately zero, indicating that the vehicle has stopped. At time t1, the engine ignition remains on. In response to the vehicle stopping, a start / stop shutdown is initiated. This may involve firing a final engine cylinder at time t2. In response to the firing of the final engine cylinder, all BPVs (e.g., each BPV of each cylinder) are then deactivated at time t2, and the BTCC valve opens.During this time, the scavenging exhaust valves remain active, allowing gases from the internal combustion engine cylinders to be routed through the scavenging exhaust manifold and the EGR channel to the intake manifold. When the scavenging exhaust valves are deactivated, they can remain closed, preventing gases from the internal combustion engine cylinders from being routed to the exhaust manifold. Immediately before time t3, the control unit can receive a request to restart the internal combustion engine (e.g., from an operator releasing the brake pedal and pressing the accelerator pedal, indicating an increase in torque demand from the stopped position). The crankshaft is turned at time t3, and the engine speed begins to increase. During this initial cranking at time t3, the scavenging exhaust valves are reactivated. The cylinders begin to fire again, and at least some of the exhaust gases can be routed through the scavenging exhaust valves to the exhaust manifold.Regular operation of internal combustion engines will resume. After a period of time, at time t4, the vehicle speed decreases to essentially zero, indicating that the vehicle has stopped. At time t5, the internal combustion engine ignition is switched off (e.g., manually by a driver). In response to the vehicle stopping (e.g., entering park) and the engine being switched off via the ignition (e.g., using the ignition key), the throttle valve closes, the BTCC valve closes, and the hot pipe valve opens. As a result, engine gases are recirculated through the scavenging exhaust manifold and the hot pipe, causing the intake manifold pressure to drop. When the engine stops rotating (engine speed reaches approximately zero), both the throttle valve and the BTCC valve open. In this way, during an ignition-key engine shutdown (as shown at time t5) and a start / stop sh...

Claims

Method comprising: under conditions during which the amount of opening of an intake throttle (62) is below a threshold amount of opening: directing intake air from an intake duct (28) to a second exhaust manifold (80) coupled to a second set of cylinder exhaust valves (6) via an exhaust gas recirculation (EGR) duct (50), including closing the intake throttle (62); heating the intake air as it passes through an EGR cooler (52) in the EGR duct (50); directing the heated intake air to an intake manifold (44) downstream of an intake throttle (62) via a flow channel (30) coupled between the second exhaust manifold (80) and the intake manifold (44); and removal of combustion gases via a first set of cylinder exhaust valves (8) to a first exhaust manifold (84) which is coupled to an exhaust channel (74). The method of claim 1 further comprising, in response to the fact that the amount of opening of the intake throttle (62) exceeds a threshold amount of opening, directing the intake air to the intake manifold (44) via the intake duct (28) and not the EGR duct (50) and directing exhaust gas from the second set of cylinder exhaust valves (6) to the intake duct (28) via the second exhaust manifold (80) and the EGR duct (50). Method according to claim 2, further comprising closing a valve arranged in the flow channel (30) in response to the fact that the amount of opening of the intake throttle (62) exceeds the threshold amount of opening. The method of claim 1, further comprising adjusting the amount of opening of a valve arranged in the flow channel (30) on the basis of a desired intake manifold pressure. Method according to claim 1, further comprising, during the routing of the heated intake air to the intake manifold (44), advancing a cam timing control of the first set of cylinder exhaust valves (8) and the second set of cylinder exhaust valves (6), wherein the advancing increases with increasing internal combustion engine load. Method according to claim 1, wherein the guiding of the intake air from the intake duct (28) to the second exhaust manifold (80) includes guiding the intake air from upstream of a compressor (162) in the intake duct (28) to the second exhaust manifold (80). Method according to claim 6, wherein the exhaust duct (74) includes a turbine (163, 164, 165), and further comprising driving the rotation of the compressor (162) via the turbine. System for an internal combustion engine, comprising: a first exhaust manifold (84) coupled to a first set of exhaust valves (8) and an exhaust port (74) incorporating a turbine (163, 164, 165); a second exhaust manifold (80) coupled to a second set of exhaust valves (6) and an intake port (28) upstream of a turbine-driven compressor (162) via an exhaust gas recirculation (EGR) port (50) incorporating an EGR cooler (52) and a first valve (54); a secondary flow port (30) incorporating a second valve (32) and coupled between the second exhaust manifold (80) and an intake manifold (44); an intake throttle (62) located in the intake port (28) downstream of the compressor (162) and upstream of the intake manifold (44) is arranged;and a control unit which includes a memory containing computer-readable instructions for: adjusting the position of each of the first valve (54), the second valve (32) and the intake throttle (62) to direct intake air from the intake port (28), through the EGR port (50) and the secondary flow port (30) and to the intake manifold (44). System according to claim 8, wherein the instructions further include instructions to open the first valve (54), open the second valve and close the intake throttle (62) in response to the throttle (62) being between a fully open and fully closed position. System according to claim 8, wherein the EGR cooler (52) is the only cooler arranged in the EGR channel (50) and the secondary flow channel (30).

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