METHOD FOR CONTROLLING A TURBINE GENERATOR IN A SPLIT EXHAUST ENGINE SYSTEM

Abstract

Method for an engine (10), comprising: Supplying exhaust gases from a first exhaust valve (E1) of all cylinders (20) from a first cylinder group to a first screw of an exhaust gas turbine (92), while simultaneously supplying exhaust gases from a first exhaust valve (E1) of all cylinders (20) from a second cylinder group to a second screw of the exhaust gas turbine (92); Supplying exhaust gases from a second exhaust valve (E2) of all cylinders (20) from the first and second cylinder groups to an exhaust catalyst (72), bypassing the exhaust turbine (92); and selective shut-off of at least one first exhaust valve (E1) of at least one cylinder (20) selected from the first and second cylinder groups in response to the fact that a turbine speed of the exhaust turbine (92) exceeds a threshold speed.

Description

Area

[0001] The present description generally concerns systems for controlling a vehicle engine which has a split exhaust manifold in order to adjust a turbine generator. Background / Brief description

[0002] Engine systems can be configured with a split exhaust manifold, with the exhaust gases from some cylinders being routed through a first exhaust manifold into the exhaust duct and the cylinder exhaust gases from other cylinders being routed through other exhaust ducts into a common tailpipe.

[0003] DE 10 2012 220 085 A1 discloses a process for an engine comprising: supplying exhaust gases from a first exhaust valve of all cylinders from a first cylinder group to an exhaust turbine while simultaneously supplying exhaust gases from a first exhaust valve of all cylinders from a second cylinder group to the exhaust turbine; supplying exhaust gases from a second exhaust valve of all cylinders from the first and second cylinder groups to an exhaust outlet, bypassing the exhaust turbine. The document shows that the exhaust lines of the first and second cylinder groups lead separately to the turbine. It is understood from common technical knowledge that a bypass line leading from the second exhaust valves to the exhaust outlet also leads to a catalyst. It is further disclosed that the valve opening times can be changed.

[0004] DE 10 2015 102 644 A1 proposes a twin scroll turbine for the turbine design.

[0005] WO 99 / 60 259 A1 and WO 2009 / 040 642 A1 show similar exhaust gas structures to the claimed method.

[0006] The subsequently published DE 10 2015 119 162 A1 discloses a method in which exhaust valves are switched off depending on the turbine speed, but the exhaust lines are designed differently than in the claimed method.

[0007] An example of a split-exhaust engine system is also illustrated by Olofsson in EP 1 127 218 B1. This system uses a multi-cylinder unit with an exhaust-driven turbine to drive a compressor. The split exhaust system connects a first exhaust valve from each cylinder to the turbine via a first exhaust path, while a second exhaust valve from each cylinder bypasses the turbine and has a direct connection to a second exhaust path leading to a catalytic converter downstream of the turbine. Valve timing adjustments can be used to control airflow to the engine via intake valves and to control the exhaust energy flow in response to changes in engine speed, directing it through the first exhaust valve to the turbine and through the second exhaust valve to the catalytic converter.

[0008] In other engine systems with a split exhaust manifold, a first exhaust valve of a cylinder can open earlier in an engine stroke to deliver an exhaust mass flow from the first part of an exhaust phase to a turbine, while a second exhaust valve can open later in the engine stroke to deliver an exhaust mass flow from the last part of the exhaust phase directly to an exhaust catalyst, bypassing the turbine. This diverts the exhaust gases away from the turbine during the later part of the exhaust phase, thus reducing pumping losses associated with high turbine backpressure.

[0009] However, the inventors identified potential problems with such split exhaust systems in this document. One weakness could be the reduced engine efficiency due to significant energy losses in the exhaust manifolds. For example, a significant portion of the exhaust energy delivered to the turbine could be lost through an extensive network of exhaust manifolds between the exhaust valves and the turbine, leading to reduced engine efficiency.

[0010] Another recognized weakness of split exhaust systems can lie in the reduced ability to control turbine speed, generator noise emissions, vibration and harshness (NVH), or component overheating, such as the cylinder head, exhaust valves, exhaust manifold, turbine, catalytic converter, etc. This can cause the turbine speed to exceed limits during engine operation, which, if left unchecked, can lead to suboptimal system performance.

[0011] Accordingly, some of these problems can be at least partially solved by the features of the independent claim. Advantageous embodiments of the invention are described in the dependent claims.

[0012] Accordingly, a method for an engine deals with supplying exhaust gases from a first exhaust valve of all cylinders in a first cylinder group to a first screw of an exhaust turbine, while simultaneously supplying exhaust gases from a first exhaust valve of all cylinders in a second cylinder group to a second screw of the exhaust turbine; and supplying exhaust gases from a second exhaust valve of all cylinders in the first and second cylinder groups to an exhaust catalyst, bypassing the turbine. The method can further include selectively shutting off the first exhaust valve of one or more cylinders in the first and second cylinder groups in response to the turbine speed exceeding a limiting speed.Thus, the volume of the exhaust manifold between a single cylinder and the turbine can be reduced by grouping cylinders, enabling more efficient delivery of exhaust energy to the turbine and minimizing energy losses. Selectively shutting off the first exhaust valve of one or more cylinders from the first and second cylinder groups can reduce the amount of exhaust mass flow to the turbine and control the turbine speed to modulate generator output and / or prevent turbine or generator failure and / or reduce generator NVH and / or improve engine efficiency.

[0013] For example, an engine may contain multiple cylinders, divided into a first and a second cylinder bank. In response to a turbine speed exceeding a turbine speed limit, one or more cylinders may be selectively shut down. For instance, the first exhaust valve of a cylinder in the first cylinder bank and a cylinder in the second cylinder bank may be selectively shut down for a predetermined period. Selectively shutting down the first exhaust valve limits the exhaust flow to the turbine, thereby reducing the turbine speed, generator output, and generator NVH (noise, vibration, and harshness) to their limits. The specific cylinder from the first and second cylinder banks may be selected based on its position on the engine block and / or its firing order, thus mitigating NVH issues along with the turbine speed.In other examples, if the turbine speed exceeds the turbine speed limit, a larger number of cylinders from the first and / or second cylinder group can be selected and their respective first exhaust valves can be selectively shut off until the turbine speed is within a desired range.

[0014] The approach described in this paper offers several advantages. For example, the method provides an improved ability to deliver exhaust energy from the engine cylinders to the turbine. Consequently, the approach reduces energy losses in the engine's exhaust manifold. Furthermore, the approach enables turbine speed control across a wide range of engine operating conditions. By controlling and limiting the turbine speed (and, consequently, the generator speed) to a desired speed (or speed range), increases in generator power, generator NVH, and component temperature can be limited to desired thresholds, thereby improving engine efficiency.Additionally, by adapting the exhaust system with a smaller network of exhaust manifolds between the cylinder and the turbine, energy losses in the exhaust system are limited, ensuring better generator performance and therefore better overall efficiency and better overall performance of the engine / generator. Brief description of the drawings Fig. Figure 1A shows a schematic representation of a self-priming engine system with a split exhaust manifold and a turbine with two worms driving a generator. Fig. Figure 1B shows a schematic representation of a self-priming engine system with a split exhaust manifold connected to a twin-screw turbine (which drives a generator) and an exhaust catalyst. Fig. Figure 2 shows a schematic representation of a combustion chamber of the engine system. Fig. 1A. Fig. Figure 3 shows a high-level flowchart illustrating an exemplary process for reducing the energy supplied to a turbine with two screws of the turbine generator in order to control the speed and / or voltage or current of a turbine generator and / or the NVH of a turbine generator and / or the component temperature. Fig. Figure 4 shows a high-level flowchart illustrating an exemplary process for determining a desired rotational speed of the turbine generator, to be used in conjunction with Fig. 3. Fig. Figure 5 shows a high-level flowchart illustrating an exemplary sequence for performing selective valve shutdown to reduce the energy supplied to the turbine with two screws of the turbine generator, to be used in conjunction with Fig. 3. Fig. Figure 6 shows an exemplary control of the intake and exhaust valves and duration during the engine's rated operation, in accordance with the present disclosure. Fig. Figure 7 shows an exemplary graphic illustrating the selective shut-off of valves in cylinders from multiple cylinder groups based on the turbine speed, generator voltage or generator current and / or the generator's NVH. Fig. Figure 8 shows an example graphic illustrating the selective deactivation of valves in cylinders from multiple cylinder groups based on engine load and / or component temperature. Detailed description

[0015] The following description concerns systems and methods for reducing the exhaust energy supplied to a twin-screw turbine driving a turbine generator in a split-flow engine system, such as the engine system in the Fig. 1A-2. The approach improves engine efficiency by reducing the dead volume between the exhaust valves and the turbine, thereby reducing the frequency of turbine overspeed conditions and turbine generator NVH.In particular, the engine system with split exhaust flow may include a first exhaust valve (hereinafter also referred to as a blow-off valve) for supplying a blow-off portion of exhaust gas from a first group of engine cylinders to a twin-screw turbine generator located in a first exhaust channel, via a first exhaust manifold, and for supplying another portion of exhaust gas from a second group of engine cylinders to the twin-screw turbine generator via a second exhaust manifold, which is not the first manifold, and a second exhaust valve (hereinafter also referred to as a suction valve) for supplying a suction portion of exhaust gas from the first and second groups of engine cylinders to an exhaust catalyst via a third exhaust manifold.In response to a turbine speed exceeding a speed limit, a generator voltage or current exceeding a power limit, and / or a generator NVH exceeding an NVH limit, an engine control unit integrated into the engine system may be configured to execute a control sequence, such as the sequence described in . Fig. 3, to selectively shut off a blow-off valve in engine cylinders from one or more cylinder groups in order to reduce the amount of exhaust energy supplied to the twin-screw turbine. An exemplary procedure for determining a desired generator speed to determine the turbine speed limit above which the blow-off valve can be selectively shut off in one or more cylinder groups is given in Fig. Figure 4 shows the number of deactivated discharge valves. Fig. 5. An example of valve controls, including valve controls of the blow-off valve during engine rated operation (i.e., without blow-off valve deactivation), is given in Fig. Figure 6 illustrates an example of adjusting the discharge valve based on the turbine speed, generator voltage or current, and / or the generator's NVH. Fig. Figure 7 illustrates this. In yet another example, the adjustment of the exhaust valve of cylinders in several cylinder groups can be carried out based on the engine load conditions and the component temperature, as shown in Figure 7. Fig. 8 shown.

[0016] By using the systems and methods described in this document, the technical effect of reducing the exhaust gas energy supplied to the turbine with two screws of the turbine generator via a selective shutdown of the blow-off valve in the engine system with split exhaust gas flow can be achieved.

[0017] Fig. Figure 1A shows a schematic diagram of a self-aspirating internal combustion engine with multiple cylinders 10, which may be included in the propulsion system of an automobile. The engine 10 may include a plurality of combustion chambers (i.e., cylinders) 20. In the example shown, the engine 10 includes four cylinders, cylinders 1 to 4, arranged in a line. In alternative examples, however, the engine 10 may include one or more cylinders, such as 2, 3, 4, 5, 6, 8, 10 or more cylinders, arranged in alternative configurations, such as V-6, I-6, V-12, 4-cylinder boxer, etc.

[0018] Each cylinder 20 of the engine 10 can be configured to receive intake air from an intake manifold 27 via an air intake duct 28. The intake duct 28 can include an air intake throttle valve 62, which is located downstream of an air filter 60. The position of the throttle valve 62 can be adjusted by the control system 15 via a throttle actuator (not shown), which is connected to the control unit 12. By modulating the throttle valve 62, a quantity of fresh air from the atmosphere can be introduced into the engine 10 and supplied to the engine cylinders at or below barometric (or atmospheric) pressure via the intake duct 28. The intake manifold 27 can be coupled to the combustion chambers via intake ports (not shown). Each intake port can supply the cylinder to which it is coupled with air and / or fuel for combustion.Each cylinder intake manifold can be selectively connected to the cylinder via one or more intake valves. In the illustrated example, each cylinder 20 is shown with two intake valves, I1 and I2. In one embodiment, an intake port can be formed by the intake manifold 27, which communicates selectively with each intake valve. In other embodiments, an intake port for a single cylinder can be divided near the cylinder into two adjacent ports with an intervening wall, each divided port being connected to a single intake valve. In another embodiment, each of the two intake valves can be controlled to open at specific engine speeds and accordingly connected to the intake manifold via a common intake port.

[0019] Each combustion chamber can discharge the combustion gases via two connected exhaust ports. In the example shown, each cylinder 20 is connected to a first exhaust port 31 via a first exhaust valve E1 and to a second exhaust port 33 via a second exhaust valve E2. Each exhaust port from each cylinder in a first and second cylinder group can lead to different exhaust manifolds to separate a first initial portion of the exhaust gas (hereinafter also referred to as the exhaust portion) and a second final portion of the exhaust gas (hereinafter also referred to as the extraction portion). For example, each of the first exhaust ports 31 of the cylinders 20 from a first cylinder group can lead to a first exhaust manifold 59a, and each of the first exhaust ports 31 of the cylinders 20 from a second cylinder group can lead to a second exhaust manifold 59b.Similarly, each of the second exhaust ports 33 from each of the cylinders 20 can lead to a third exhaust manifold 57. This allows each combustion chamber 20 of the first and second cylinder groups to discharge a portion of the combustion gases via a first exhaust valve E1 into the first exhaust manifold 59a or a second exhaust manifold 59b, and to discharge a portion of the combustion gases via a second exhaust valve E2 into the third exhaust manifold 57.

[0020] Such an exhaust system with three exhaust manifolds, two manifolds for guiding the exhaust gas discharge and the third manifold for guiding the exhaust gas extraction, is referred to in this document as the "split exhaust gas flow system".

[0021] The engine 10 can include a turbine-driven generator 190, which is located in a first exhaust channel 55a (coupled with the first exhaust manifold 59a) and a second exhaust channel 55b (coupled with the second exhaust manifold 59b). The turbine-driven generator 190 can include a twin-screw extraction turbine 92 and a generator 94, which are coupled on a common shaft. Furthermore, a bypass valve 127a and 127b can be part of a bypass 166, which is coupled between an inlet and an outlet of the twin-screw extraction turbine to control the amount of exhaust gas supplied to the twin-screw turbine. In some examples, the bypass valve may be included along both exhaust channels 55a and 55b, and in other examples, the bypass valve may not be included at all.In such systems without a bypass valve, the amount of exhaust gas supplied to the turbine can be controlled mainly by switching off the discharge valves.

[0022] As discussed above, the exhaust manifolds can be designed to route the exhaust and exhaust gas components separately. The exhaust manifold 59a can route the first part of the exhaust pulse from the first cylinder group via the first exhaust channel 55a to the turbine 92 of the turbine generator 190, and the exhaust manifold 59b can route the second part of the exhaust pulse from the second cylinder group to the turbine 92, while the exhaust manifold 57 can route the exhaust gas component via a third exhaust channel 162 into a section located downstream of the turbine 92 and upstream of a pollutant limitation device 72.For example, exhaust valves E1 direct the first exhaust portion of the exhaust gases from the first cylinder group through exhaust manifold 59a and the first exhaust channel 55a to the twin-scroll turbine, and the second exhaust portion of the exhaust gases from the second cylinder group through exhaust manifold 59b and the second exhaust channel 55b, while exhaust valves E2 direct the exhaust portion of the exhaust gases via the second exhaust channel 162 through exhaust manifold 57 to the pollutant control device 72. Therefore, the first exhaust valve of cylinders from the first and second cylinder groups can open earlier than the second exhaust valve and close earlier than the second exhaust valve.

[0023] Exhaust gases exiting turbine 92 can nevertheless flow through the emissions control device 72. In one example, the emissions control device 72 can comprise several catalyst modules. In another example, several emissions control devices, each comprising multiple modules, can be used. In some examples, the emissions control device 72 can be a three-way catalyst. In other examples, the emissions control device 72 can include one or more diesel oxidation catalysts (DOC) and a selective catalytic reduction (SCR) catalyst. After the exhaust gas has passed through the emissions control device 72, it can be directed to the outside via an exhaust pipe 58.

[0024] This allows the combustion gases leaving a cylinder to be split into two parts via three different exhaust channels formed by the split exhaust manifold. For example, in a combustion cycle, the first exhaust valve E1 of cylinder 20 can direct a first part of the exhaust gases, namely the blow-off portion, from both the first and second cylinder groups to the turbine 92 via a first exhaust channel 55a and a second exhaust channel 55b, respectively. A second exhaust valve E2 of the same cylinder (20) then directs a final part of the exhaust gases, after the blow-off portion, from both cylinder groups via the second channel 162 to a pollutant control device 72. The final part of the exhaust gases exiting via the second exhaust valve E2 can consist primarily of the exhaust gas extraction portion.

[0025] In Fig. Figure 1A shows injectors directly coupled to the combustion chambers to inject fuel proportionally to the pulse width of a fuel pulse width signal, which is received by the control unit 12, for example, via an electronic control signal. Each cylinder 20 is shown coupled to two injectors 74 and 76 per cylinder at each intake valve. Thus, the injectors provide direct fuel injection into the combustion chamber. Each injector can be mounted, for example, on the side of the respective combustion chamber or on top of the respective combustion chamber. In some examples, one or more injectors can be arranged in the intake manifold 27 in a configuration that provides nozzle injection of fuel into the intake ports upstream of the respective combustion chambers. Although not in Fig. As shown in Figure 1A, fuel can be supplied to the injectors by a fuel system which includes a fuel tank, a fuel pump, a fuel line and a fuel distributor.

[0026] In some examples, a distributorless ignition system (not shown) can, in response to the control unit 12, provide an ignition spark for the spark plugs (not shown) which are coupled to the combustion chambers 20.

[0027] The motor 10 can be controlled, at least partially, by a control system 15, which includes a control unit 12, and by input from a driver via an input device, for example, an input via a brake pedal, as shown below. Fig. 2 discussed. It is shown that the control system 15 receives information from a variety of sensors 16 (for which various examples are described in this document) and sends control signals to a variety of actuators 81. For example, the sensors 16 may include turbocharger intake pressure sensors, temperature sensors, and manifold air pressure sensors located in the intake manifold. Other sensors may include a throttle valve intake pressure sensor for estimating throttle valve intake pressure and / or a throttle valve inlet temperature sensor for estimating throttle valve air temperature, which is coupled downstream of the throttle valve in the intake manifold. Additional sensors and actuators of the system are described below with reference to Fig. 2 discussed. Furthermore, the actuating elements 81 can include, for example, fuel injectors and the throttle valve 62. The control unit 12 can receive input data from the various sensors, process the input data, and trigger the actuating elements in response to the processed input data according to the instruction or the code programmed therein, in accordance with one or more sequences. Exemplary control sequences are described in this document with reference to the Fig. 3-5 described.

[0028] By providing an exhaust flow from cylinders in the first cylinder group via a first screw and an exhaust flow from cylinders in the second cylinder group via a second screw, the need for the extensive network of exhaust manifolds is reduced, thereby limiting energy losses in the exhaust system and improving engine performance.

[0029] With reference to Fig. Figure 1B shows a three-dimensional view of a self-aspirating internal combustion engine with multiple cylinders 10, which may be included in a drive system of an automobile. Therefore, the above in Fig. Components introduced in Figure 1A are represented with the same reference numerals and are not reintroduced. The engine 10 can include a plurality of combustion chambers. In the example shown, the engine 10 includes a blow-off valve 31 and a suction valve 33 for four cylinders arranged in a row.

[0030] The exhaust valve in a first and second cylinder can be connected to a first exhaust manifold 59a, which leads to a first exhaust channel 55a, which is connected to a turbine with two screws 92, which is coupled to a generator 94. In this document, the first and second cylinders can be cylinders from the same group, such as cylinder 1 and cylinder 2 in Fig. 1A. The exhaust valve in a third and fourth cylinder can also be connected to a second exhaust manifold 59b, which leads to a second exhaust channel connected to the turbine with two screws. In this document, the third and fourth cylinders can be cylinders from the same cylinder group, such as cylinders 3 and 4 in Fig. 1A. A turbine flange 56 can be coupled to the turbine 92 via a connection between the first exhaust manifold 59a and the second exhaust manifold 59b. As illustrated by the cross-sectional view of the turbine flange through plane MM', the first and second exhaust channels can be connected to the twin-scroll turbine via separate inlets. Thus, the exhaust gases flowing from the exhaust valves in cylinders 1 and 2 to the turbine via a first exhaust channel, and the exhaust gases flowing from the exhaust valves in cylinders 3 and 4 to the turbine via a second exhaust channel, reduce the volume of the exhaust manifold between each individual cylinder and the turbine, minimize energy losses, and efficiently deliver exhaust energy to the turbine, resulting in improved engine efficiency.

[0031] The extraction valve 33 in all cylinders can be connected to a common exhaust gas channel 57, thereby bypassing the twin-screw turbine and leading to a pollutant control device 72, which is located downstream of the twin-screw turbine. After the exhaust gas has passed through the pollutant control device 72, it can be directed to the outside via an exhaust pipe 58.

[0032] With reference to Fig. 2 shows the Fig. a partial view of a single cylinder of an internal combustion engine 10. Therefore, the above in Fig. The components introduced in 1A are represented with the same reference numerals and are not introduced again. The motor 10 can be controlled, at least partially, by a control system, which includes a control unit 12, and by input from a driver 214 via an input device 216. In this example, the input device 216 includes an accelerator pedal and a pedal position sensor 218 for generating a proportional pedal position signal (PP).

[0033] Engine 10 is shown with combustion chamber (cylinder) 20, cooling sleeve 213, and cylinder walls 232, with piston 236 arranged therein and connected to crankshaft 240. The combustion chamber 20 is shown such that it is connected to the intake port 146 and the exhaust port 148 via an intake valve 252 and an exhaust valve 256, respectively. As above in Fig. As described in Figure 1A, each cylinder of engine 10 can discharge combustion products via two channels. In the illustrated view 200, the exhaust channel 148 represents the first exhaust port, which leads from the cylinder to the turbine (such as exhaust port 33 in Figure 1). Fig. 1A), while the second exhaust channel, which leads to the exhaust catalyst, is not visible in this view.

[0034] As also mentioned above in Fig. As implemented in 1A, each cylinder of the engine 10 can include two (or more) intake valves and two (or more) exhaust valves. In the illustrated view 200, the intake valve 252 and the exhaust valve 256 are located in an upper region of combustion chamber 20. The intake valve 252 and the exhaust valve 256 can be controlled by a control unit 12 using cam actuation systems, which include one or more cams. The cam actuation systems can use one or more of the following: cam profile adjustment (CPS), variable cam timing (VCT), variable valve timing (VVT), and / or variable valve lift (VVL) systems to vary the valve actuation. In the illustrated example, each intake valve 252 is actuated by an intake cam 251, and each exhaust valve 256 is actuated by an exhaust cam 253. The position of the intake valve 252 and the exhaust valve 256 can be determined by valve position sensors 255 and 257, respectively.

[0035] In alternative embodiments, the intake and / or exhaust valve can be controlled by electronic valve actuation. For example, cylinder 20 can alternatively include an intake valve controlled by electronic valve actuation and an exhaust valve controlled by cam actuation systems, including CPS and / or VCT systems. In still other embodiments, the intake and exhaust valves can be controlled by a common valve actuation element or valve actuation system, or by a variable valve actuation element or variable valve actuation system.

[0036] In one example, the intake cam 251 includes separate and distinct cam humps, which provide different valve profiles (e.g., valve timing, valve lift, duration, etc.) for each of the two intake valves of combustion chamber 20. Similarly, the exhaust cam 253 can include separate and distinct cam humps, which provide different valve profiles (e.g., valve timing, valve lift, duration, etc.) for each of the two exhaust valves of combustion chamber 20. In another example, the intake cam 251 can include a common hump or similar humps, which provide each of the two intake valves with a substantially similar valve profile.

[0037] Additionally, different cam profiles can be used for the various exhaust valves to separate exhaust gases discharged at low cylinder pressure from those discharged at high extraction pressure. For example, a first exhaust cam profile can open the first exhaust valve from the closed position shortly before bottom dead center (BDC) of the power stroke of combustion chamber 20 and close the same exhaust valve sufficiently before top dead center (TDC) to selectively discharge blow-off gases from the combustion chamber. Furthermore, a second exhaust cam profile can be arranged such that a second exhaust valve opens from the closed position approximately midway through the exhaust stroke and closes before TDC to selectively discharge the extraction portion of the exhaust gases.

[0038] With further reference to Fig. Figure 2 shows an exhaust gas sensor 226, which is coupled to the exhaust gas channel 148. Sensor 226 can be arranged in the exhaust gas channel upstream of one or more pollutant limitation devices, such as device 72 in Figure 2. Fig. 1A. Sensor 226 may be selected from various suitable sensors to provide an indication of an exhaust air-fuel ratio, such as a linear lambda sensor or UEGO (universal or wide-range exhaust oxygen), a dual-state lambda sensor or EGO (as shown), a HEGO (heated EGO), a NOx, HC, or CO sensor. Downstream emissions control devices may include one or more of the following: a three-way catalytic converter (TWC), a NOx trap, various other emissions control devices, or combinations thereof.

[0039] The exhaust gas temperature can be estimated by one or more temperature sensors (not shown) located in exhaust duct 148. Alternatively, the exhaust gas temperature can be inferred from engine operating conditions, such as engine speed, load, air-fuel ratio (AFR), ignition timing, etc.

[0040] Cylinder 20 can have a compression ratio that is the volume ratio between piston 236 at bottom dead center and piston 236 at top dead center. Traditionally, the compression ratio is in the range of 9:1 to 10:1. However, in some examples, different fuels are used, which can potentially increase the compression ratio. This can occur, for example, when fuels with a higher octane rating or fuels with a higher latent heat of vaporization are used. The compression ratio can also be higher when direct injection is used, as this affects ignition knock.

[0041] In some embodiments, each cylinder of engine 10 may include a spark plug 91 to initiate combustion. The ignition system 288 can provide a spark to the combustion chamber 20 via the spark plug 91 in response to a pre-ignition signal SA from control unit 12 under selected operating modes. However, in some embodiments, the spark plug 91 may be omitted, for example, if the engine 10 can initiate combustion by auto-ignition or by fuel injection, as in some diesel engines.

[0042] In some embodiments, each cylinder of the engine 10 can be configured with one or more injectors to supply fuel to it. As a non-limiting example, cylinder 20 is shown with an injector 66. According to the illustration, the injector 66 is directly coupled to the combustion chamber 20 to inject fuel directly into it proportionally to the pulse width of a fuel pulse width signal, which is received by the control unit 12 via the electronic control 268. Thus, the injector 66 provides direct injection (hereafter also referred to as "DI") of fuel into the combustion cylinder 20. Fig. Figure 2 shows the injector 66 as a side-mounted injector; however, it can also be located above the piston, for example, near the position of the spark plug 91. Such an arrangement can improve mixing and combustion when the engine is operated with an alcohol-based fuel, since some alcohol-based fuels have lower volatility. Alternatively, the injector can be located above and near the intake valve to improve mixing. In an alternative embodiment, the injector 66 can be a nozzle injector that supplies fuel to the intake manifold upstream of cylinder 20.

[0043] Fuel can be supplied to the injector 66 via a high-pressure fuel system 8, 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 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. Fuel tanks in the fuel system 8 can contain fuel with different properties, such as 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 8 can be coupled with a fuel vapor recovery system, which includes a canister for storing fuel for refueling and the daily fuel vapors. During engine operation, the fuel vapors can be purged from the canister into the engine cylinders when the purging conditions are met. For example, the purging vapors can be drawn naturally into the cylinder via the first intake port at or below barometric pressure.

[0044] Control unit 12 is in Fig. Figure 2 is represented as a microcomputer, comprising 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 constitutes 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 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 212, which is coupled to the cooling sleeve 213; a profile ignition pulse (PIP) signal from Hall effect sensor 220 (or other type), which is coupled to the crankshaft 240; the throttle position (TP) from a throttle position sensor; the manifold absolute pressure (MAP) signal from sensor 98; the cylinder AFR from EGO sensor 226; and abnormal combustion from a knock sensor and a crankshaft acceleration sensor. The 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 indicate a vacuum or pressure in the intake manifold.

[0045] Based on data from one or more of the aforementioned sensors, the control unit 12 can adjust one or more actuators, such as the fuel injector 66, the throttle valve 62, the spark plug 91, the intake / exhaust valves and cams, etc. The control unit can receive data from the various sensors, process the data, and trigger the actuator in response to the processed data according to instructions or code programmed therein, which correspond to one or more sequences. For example, in response to the turbine speed exceeding a limit, the control unit can deactivate a valve mechanism coupled to an exhaust valve of at least one cylinder in a first and second cylinder bank to reduce the exhaust gas flow from the cylinder to the turbine. Exemplary control routines are described below with reference to the Fig. 3-5 described.

[0046] Thus, the system enables the Fig. 1-2 A method for an engine, comprising: supplying exhaust gases from a first exhaust valve of all cylinders of a first cylinder group to a first screw of an exhaust turbine, while simultaneously supplying exhaust gases from a first exhaust valve of all cylinders of a second cylinder group to a second screw of the exhaust turbine; and supplying exhaust gases from a second exhaust valve of all cylinders of the first and second cylinder groups to an exhaust catalyst, bypassing the turbine. The method further comprises selectively shutting off the first exhaust valve of one or more cylinders of the first and second cylinder groups in response to a turbine speed exceeding a limit speed. In addition, the method may include driving a generator via the turbine.

[0047] With reference to Fig. 3 is a method 300 for adjusting the blow-off exhaust gas, which is supplied to a turbine with two screws of a turbine generator (e.g. turbine generator 190 in Fig. 1A) is provided, which is located in a split exhaust system. For example, the amount of exhaust gases supplied to the turbine can be reduced to address one or more of the following: excessive turbine speed, generator output, generator NVH, and component overheating (such as cylinder head, exhaust valves, exhaust manifold, turbine, catalytic converter, etc.). Instructions for carrying out Method 300 and the other methods contained in this document can be executed by a control unit using instructions stored in a memory of the control unit and in conjunction with signals received from sensors of the engine system, such as those referred to above. Fig. 1-2 described sensors. The control unit can use actuators of the internal combustion engine to adjust the internal combustion engine operation according to the procedures described below.

[0048] In 302, procedure 300 involves estimating and / or measuring engine operating conditions. Operating conditions may include, but are not limited to, the following: driver torque demand, electrical load, MAP, MAF, turbine speed, generator speed, generator power (voltage or current), generator NVH, engine speed, engine load, accelerator pedal position, throttle position, vehicle speed, engine temperature, exhaust mass flow, exhaust temperature, temperature of various components (such as cylinder head, exhaust valves, exhaust manifold, turbine, catalytic converter, etc.), and ambient conditions, such as temperature. Generator power (voltage or current) and generator NVH can be inferred from the speed of a turbine driving the generator, with generator power and generator NVH increasing as turbine speed increases.Alternatively, the generator's NVH can be inferred from generator conditions, such as one or more of the following: generator output voltage, generator output current, and generator output power. Furthermore, the component temperature can be inferred from engine load / speed, exhaust gas temperature, ambient temperature, vehicle speed, etc. Additionally or alternatively, the component temperature can be measured directly using a temperature sensor coupled to the engine.

[0049] In the case of 304, procedure 300 may include determining a desired generator speed based on the estimated operating conditions to maintain a desired generator output and reduce the generator's NVH below a limit. Alternatively, the control unit may determine a target turbine speed that keeps the generator's NVH below a limit. Details on determining the desired turbine or generator speed are given with reference to Fig. 4 is discussed further. Next, the procedure described in 306 can include determining a turbine speed limit based on the desired generator speed under the current engine speed-load conditions. Therefore, the turbine speed limit can be a turbine speed above which the turbine efficiency may decrease. Alternatively, the turbine speed limit can be a turbine speed above which the turbine power and the generator's NVH can be reduced at the current exhaust gas and ambient temperatures.

[0050] After determining the desired speed limit, procedure 300 at 308 may include determining whether the actual turbine speed exceeds the turbine speed limit. The actual turbine speed can be measured by a sensor coupled to the turbine shaft or inferred from the turbine conditions. If the answer at 308 is YES, the procedure can proceed to 312. At 312, the procedure may include selectively shutting down individual valve mechanisms for a first exhaust valve of one or more cylinders from a first and second cylinder group to reduce the turbine speed. For example, the individual valve mechanisms may be shut down during a first operating condition corresponding to a first cylinder pattern, in which the turbine speed is above the speed limit.In another example, the individual valve mechanisms can be deactivated according to a second cylinder pattern during a second operating condition in which the turbine speed exceeds the speed limit, where the second operating condition differs from and is mutually exclusive with the first. In yet another example, the individual valve mechanisms can be deactivated according to a third cylinder pattern during a third operating condition in which the turbine speed exceeds the speed limit, where the third operating condition differs from and is mutually exclusive with both the first and second operating conditions. Each of the first, second, and third cylinder patterns can be based on one or more of the following: turbine speed, engine speed, engine load, engine temperature, and gear selection.For example, in the first, second and third cylinder pattern, a number and identity of cylinders can be selected based on the turbine speed in relation to the speed limit, the first exhaust valve of which is selectively shut off, as with reference to . Fig. 5 discussed. As a non-restrictive example, the first, second, and third turbine overspeed conditions may be associated with different generator power outputs and generator NVH (since the turbine drives the generator), and thus the first, second, and third cylinder patterns may differ. As another example, the first, second, and third turbine overspeed conditions may be associated with different engine temperatures, and thus the first, second, and third cylinder patterns may differ. The first exhaust valve in one or more cylinders from the first and / or second cylinder group may be selectively shut off via hydraulically actuated lift elements, a disconnect pin in the valve train, an idle mechanism, or a cam profile adjustment mechanism (CPS), whereby a cam profile without lift may be used for shut-off valves.In one example, the deactivation of the first exhaust valve in one or more cylinders from the first and second cylinder groups can be controlled by a cam-based VDE actuator. In another example, a single cylinder valve actuator can selectively deactivate the first exhaust valve in one or more cylinders from the first and second cylinder groups. Therefore, the deactivated first exhaust valve in one or more cylinders from the first and second cylinder groups can be held in a closed position (or held in a fixed position) for a period of time. Details on deactivating the first exhaust valve in one or more cylinders from the first and second cylinder groups to reduce turbine speed are given with reference to [reference missing]. Fig. 5 discussed further.

[0051] Returning to 308, if it is determined that the turbine speed is below the turbine speed limit, the procedure can proceed to 310 to determine whether any generator output (voltage or current) is above a power limit. Therefore, the power limit can be determined based on the desired turbine speed and reflects a maximum power output above which engine power could be adversely affected. If the answer at 310 is YES, the procedure can proceed to 312 to selectively shut off the first exhaust valve in one or more cylinders from the first and second cylinder groups to reduce the turbine speed. By reducing the turbine speed, the generator output voltage or current can be lowered and kept within the limits.For example, the individual valve mechanisms can be shut off according to a second cylinder pattern with a number and identity of cylinders whose first exhaust valve is selectively shut off, selected based on the turbine speed above the speed limit and a higher generator output (voltage or current), as referred to in . Fig. Section 5 discusses this. In one example, the second cylinder pattern might be selected in response to the turbine speed exceeding a speed limit and a higher generator output. Furthermore, the second cylinder pattern might reduce the turbine speed to a value below the turbine speed drop achieved by the first cylinder pattern, which was selected in response to a turbine speed increase.

[0052] If the answer to 310 is NO (e.g., the generator output is below the power limit), the procedure can proceed to 314. Procedure 314 may involve determining whether the difference between the generator's actual NVH and its NVH limit is greater than a difference limit. The generator's actual NVH may be inferred from engine operating conditions, such as turbine speed, or estimated using a vibration sensor. For example, increased generator NVH may occur if the turbine speed exceeds a limit. If the answer to 314 is YES, the procedure can proceed to 312 to selectively shut down the first exhaust valve in one or more cylinders from the first and second cylinder groups to reduce the turbine speed. Reducing the turbine speed can decrease turbine generator vibration.For example, the individual valve mechanisms can be shut down according to a third cylinder pattern with a number and identity of cylinders whose first exhaust valve is selectively shut down, selected due to the fact that the turbine speed is above the speed limit (and higher generator vibration), as referred to in . Fig. 5 discussed. In one example, the third cylinder pattern may be selected in response to the turbine speed exceeding a speed limit and the generator vibration increasing. Furthermore, the third cylinder pattern may reduce the turbine speed to a value below the turbine speed drop achieved by the first cylinder pattern, which was selected in response to an increase in turbine speed and lower generator vibration. For example, the number of cylinders whose first exhaust valve is shut off may be the same in the first, second, and third cylinder patterns, although the identity of the cylinders may differ. In still other examples, the number of shut-off cylinders may vary. Details of the selective shut-off of the first exhaust valve to reduce turbine speed and, consequently, generator vibration are discussed with reference to Fig. 5 discussed further.

[0053] If the answer to 314 is NO (i.e., if the difference between the actual generator vibration and the vibration limit is less than the difference limit), the procedure can proceed to 316 to determine whether a component's actual temperature is above a component temperature limit. Therefore, the component temperature limit can be determined based on a desired engine load condition and engine speed, and reflect a maximum component temperature above which engine performance could be impaired. If the answer to 316 is YES, the procedure can proceed to 312 to perform a shutdown of the first exhaust valve in one or more cylinders from the first and second cylinder groups to reduce the component temperature.For example, the individual valve mechanisms can be switched off according to a fourth cylinder pattern with a number and identity of cylinders, the first exhaust valve of which is switched off based on the component temperature, as with reference to . Fig. 5 discussed.

[0054] If the answer to 316 is NO (i.e., if the component temperature is below the component temperature limit), the procedure can proceed to 318. Procedure 318 may include operating the engine without shutting off the blow-off valve. That is, if it is determined that the turbine speed is below the speed limit, the generator output is below the power limit, the generator vibration is below the vibration limit, and the component temperature is below the component temperature limit, the valve shut-off to reduce exhaust energy to the turbine can be omitted, and the engine can be operated with all first valves of all engine cylinders open.In other words, the engine can be operated in a nominal mode, whereby nominal engine operation includes, for example, the initial opening of the first exhaust valve of each cylinder during an engine stroke to deliver a first portion of the exhaust energy to the turbine via the blow-off valve, and subsequently the opening of a second exhaust valve of the same cylinder during the same engine stroke to deliver a final portion of the exhaust energy to the catalytic converter. Details of nominal engine operation are provided with reference to [reference to be inserted here]. Fig. 6 discussed further.

[0055] Problems related to turbine overspeed conditions (including generator power and generator NVH) and component overtemperature conditions can be addressed by a control unit selectively shutting off the first exhaust valve of one or more cylinders from the first and second cylinder groups to reduce the amount of blow-off energy supplied to the twin-screw turbine.

[0056] It is understood that in alternative examples, in addition to the selective deactivation of individual first exhaust valve mechanisms, in response to the fact that the turbine speed is greater than the speed limit, or the generator power is higher than the power limit, or the difference between the generator vibration and the generator vibration limit is greater than a difference limit, an overflow valve in the first and second exhaust channel (e.g., valves 127a and 127b in Fig. 1A), which supplies exhaust gases from the engine cylinders to the turbine, can be adjusted so that the exhaust gas mass flow to the turbine is limited in the sense of reducing the turbine speed.

[0057] With reference to Fig. 4 is an exemplary method 400 for determining a desired generator speed of a turbine generator (e.g. turbine generator 190 in Fig. 1A), which is located in a first exhaust manifold and in a second exhaust manifold (e.g. first exhaust manifold 59a and second exhaust manifold 59b in Fig. 1A) of an engine system with a split exhaust manifold (e.g. engine system 10 in Fig. 1A), shown. The desired generator speed may be a generator speed at which the turbine generator can operate with the desired generator output and lower generator NVH under current engine operating conditions (such as with NVH below a limit). The procedure in Fig. 4 can be used in conjunction with the procedure in Fig. 3 can be used. For example, procedure 400 can be performed at step 304 of procedure 300. The procedure in Fig. 4 can be stored as executable instructions in the non-volatile memory of control unit 12 in the Fig. 1A - 2 should be stored.

[0058] Procedure 402 may include determining the engine operating conditions, including engine load, engine speed, turbine speed, exhaust gas temperature, and exhaust gas mass flow to the turbine. After determining the engine operating conditions, procedure 404 includes determining a desired generator speed (or speed range) based on the current engine speed / load conditions and the exhaust gas mass flow to the twin-screw turbine. The desired generator speed or speed range may correspond to a range in which the generator output at a desired power level and the generator's NVH (noise, vibration, and harshness) are kept below a limit that may be disturbing to the driver. This limit may vary depending on the operating conditions, such as the vehicle speed.In one example, the desired generator speed can be determined using a reference table that lists the desired generator speed as a function of the engine load and engine speed. Alternatively, the desired generator speed can be based on the turbine efficiency. In one example, generator power and generator vibration can increase with increasing engine speed. In another example, generator power and generator vibration can increase with increasing mass exhaust gas flow to the turbine.

[0059] Once the desired generator speed has been determined, the control unit can further adjust the turbine speed to maintain the generator at the desired generator speed (or speed range).

[0060] The vibration of the turbine generator can be adjusted by setting the desired generator speed based on engine load conditions / engine speed and exhaust gas flow to the turbine for improved efficiency and better performance.

[0061] With reference to Fig. Figure 500 describes an exemplary method for selectively shutting down the first exhaust valve of one or more cylinders of a first and / or second cylinder group to reduce the exhaust energy supplied to a turbine of a turbine generator in order to reduce turbine overspeed conditions. The method also enables generator power to be maintained at limit values, generator vibration to be reduced, and cylinder overheating to be addressed.

[0062] The procedure in Fig. 5 can be used in conjunction with the procedure in Fig. 3 can be used. For example, procedure 500 can be performed at step 312 of procedure 300. The procedure in Fig. 5 can be stored as executable instructions in the non-volatile memory of control unit 12 in the Fig. 1A - 2 should be stored.

[0063] Procedure 500, as described in 502, may include determining and / or estimating engine operating conditions. Engine operating conditions include, but are not limited to, turbine speed, generator speed, generator power (voltage or current), generator vibration, engine speed, accelerator pedal position, throttle position, vehicle speed, engine temperature, component temperature, exhaust mass flow, and engine load. Procedure 504 may then include determining (estimating or inferring) a turbine speed, generator power, actual generator NVH, and component temperature. Additionally, a generator power limit, a generator NVH limit, and a component temperature limit may be retrieved from the control unit's memory or determined based on the engine operating conditions.Therefore, the generator power limit, the generator's NVH limit, and the component temperature limit can be based on engine speed, engine load, and exhaust gas flow into the turbine. Furthermore, the generator power limit and the NVH limit can be based on vehicle speed and turbine speed.

[0064] The procedure in 506 may then include selecting one or more exhaust valves to be shut off and the duration of the shutdown based on the turbine speed. In one example, selecting the one or more exhaust valves to be shut off includes determining whether the turbine speed is above the turbine speed limit. If the answer is yes, the procedure can proceed to 508. In 508, the procedure may include determining the number and identity of cylinders from the first and second cylinder groups whose first exhaust valve is selectively shut off based on a difference between the turbine speed and the turbine speed limit. Additionally, the duration of the selective shutdown of the first exhaust valve in the selected one or more cylinders from the first and second cylinder groups may be based on the difference between the turbine speed and the turbine speed limit.

[0065] If the difference is greater than a first threshold, for example, a smaller number of cylinders can be selected for shutdown and / or the first exhaust valve of the selected cylinders can be shut down for a shorter period. If the difference is greater than a second threshold, where the second threshold is greater than the first, a larger number of cylinders can be selected for shutdown and / or the first exhaust valve of the selected cylinders can be shut down for a longer period. The number and identity of the cylinders selected for shutdown can be adjusted to provide a first cylinder pattern based on the turbine speed.

[0066] For example, an inline engine may have four cylinders, which are divided into cylinder groups, each consisting of two cylinders, and each cylinder having a first exhaust valve and a second exhaust valve. In this document, if the difference between the turbine speed and the turbine speed limit is greater than the first limit, a single cylinder from the first cylinder group or a single cylinder from the second cylinder group may be selected, and the first exhaust valve of the selected cylinder may be deactivated (while the second exhaust valve remains open). Alternatively, a single cylinder from the first cylinder group and a single cylinder from the second cylinder group may each be selected, and the first exhaust valve of the selected cylinders may be deactivated (while the second exhaust valve remains open).The individual cylinder from the first cylinder group and the individual cylinder from the second cylinder group can be selected based on their position along an engine block and / or their firing order. For example, if the four cylinders are numbered 1-4 from one side of the engine block to the other, with cylinders 1-2 grouped as a first cylinder group and cylinders 3-4 as a second cylinder group, and with the cylinders firing in the sequence 1-3-4-2, then cylinders 1 and 4 together can be selected to shut off the first exhaust valve, or cylinders 2 and 3 together can be selected to shut off the first exhaust valve.

[0067] Referring to the same engine configuration, if the difference between the turbine speed and the turbine speed limit is greater than the second limit, both cylinders from the first cylinder group and both cylinders from the second cylinder group can be selected, and the first exhaust valve of all selected cylinders can be closed. In this example, the first exhaust valve of all cylinders can be closed, while the cylinders continue to operate and the intake valves and the second exhaust valve continue to open and close during the engine stroke. In another example, the first and second limits can be associated with different generator outputs (voltage or current) and generator NVH characteristics. For instance, the first limit can be associated with a lower generator output (voltage or current) and less generator NVH than the second limit.

[0068] Returning to 506, if the turbine speed is not greater than the turbine speed limit, the procedure can proceed to 510. In 510, the procedure may include determining whether a generator output is greater than a power limit. If the answer is yes, the procedure can proceed to 512. In 512, the procedure may include selecting one or more exhaust valves to shut down and a duration of shut-off based on the turbine speed. In one example, selecting the one or more exhaust valves to shut down includes determining the number and identity of cylinders from the first and second cylinder groups whose first exhaust valve is selectively shut down based on a difference between the generator output and the power limit.Additionally, the duration of the selective shutdown of the first exhaust valve in the selected one or more cylinders from the first and second cylinder groups can be based on the difference between the generator output and the power limit. For example, if the difference is greater than a first limit, a smaller number of cylinders can be selected for shutdown and / or the first exhaust valve of the selected cylinders can be shut down for a shorter period. If the difference is greater than a second limit, where the second limit is greater than the first limit, a larger number of cylinders can be selected for shutdown and / or the first exhaust valve of the selected cylinders can be shut down for a longer period.The number and identity of the cylinders selected for shutdown can be adjusted to provide a second cylinder pattern based on the fact that the turbine speed is above the limit (and the generator power is greater).

[0069] The second cylinder deactivation pattern can differ from the first. For example, the first and second cylinder patterns may have a different total number of deactivated cylinders. In another example, the first and second cylinder patterns may have the same total number of deactivated cylinders, but the identity of the deactivated cylinders may differ.

[0070] Returning to 510, if the generator output is not greater than the output limit, the procedure can proceed to 514. In 514, the procedure may involve determining whether the difference between the generator's actual NVH and an NVH limit is greater than a difference limit. If the answer in 514 is yes, the procedure can proceed to 516. In 516, the procedure may involve selecting one or more exhaust valves to shut down and the duration of the shutdown based on the generator's NVH. In an example, selecting the one or more exhaust valves to shut down may involve determining the number and identity of cylinders from the first and second cylinder groups whose first exhaust valve is selectively shut down based on the difference between the generator's actual NVH and the NVH limit.Additionally, the duration of the selective shutdown of the first exhaust valve in the selected one or more cylinders from the first and second cylinder groups can be based on a relative vibration, which is defined in this document as the difference between the generator vibration and the vibration limit. For example, if the difference is greater than a first limit, a smaller number of cylinders can be selected for shutdown and / or the first exhaust valve of the selected cylinders can be shut down for a shorter period. If the difference is greater than a second limit, where the second limit is greater than the first limit, a larger number of cylinders can be selected for shutdown and / or the first exhaust valve of the selected cylinders can be shut down for a longer period.The number and identity of the cylinders selected for shutdown can be adjusted to provide a third cylinder pattern based on the fact that the turbine speed is above the limit (and the generator vibration is greater).

[0071] The third cylinder shutdown pattern may differ from the first cylinder shutdown pattern in response to the turbine speed being higher than the speed limit (resulting in lower generator vibration). For example, the first, second, and third cylinder patterns may have a different total number of cylinders shut down. In another example, the first, second, and third cylinder patterns may have the same total number of cylinders shut down, but the identity of the shut-down cylinders may differ.

[0072] Returning to 514, if the answer to 514 is NO, i.e., if there is no difference between the actual generator vibration and the vibration limit, the procedure can proceed to 518. In 518, the procedure may involve determining whether a component temperature is higher than a component temperature limit. If the answer to 518 is YES, i.e., if there is a difference between the actual component temperature and the component temperature limit, the procedure may proceed to 520. In 520, the procedure may involve selecting one or more exhaust valves to shut down and a duration of shut-off based on the component temperature. In an example, selecting the one or more exhaust valves to shut down may involve determining the number and identity of cylinders from the first and second cylinder groups whose first exhaust valve is selectively shut down based on the difference between the component temperature and the component temperature limit.Additionally, the duration of the selective shutdown of the first exhaust valve in the selected one or several cylinders from the first and second cylinder groups can be based on the engine load being greater than an engine load limit.

[0073] A series of cylinders whose first exhaust valve is selectively deactivated, and the duration of the deactivation, can be selected based on the difference between the component temperature and the component temperature limit. For example, if the difference is greater than a first temperature limit, a smaller number of cylinders can be selected for deactivation and / or the first exhaust valve of the selected cylinders can be deactivated for a shorter period. If the difference is greater than a second temperature limit, where the second temperature limit is greater than the first temperature limit, a larger number of cylinders can be selected for deactivation and / or the first exhaust valve of the selected cylinders can be deactivated for a longer period.

[0074] The number and identity of the cylinders selected for shutdown can be adjusted to provide a fourth cylinder pattern based on component temperature. This fourth cylinder pattern can differ from the first cylinder shutdown pattern based on turbine speed, the second cylinder shutdown pattern based on generator output, and the third cylinder shutdown pattern based on generator vibration. For example, the first, second, third, and fourth cylinder patterns can have different total numbers of cylinders shut down. In another example, the first, second, third, and fourth cylinder patterns can have the same total number of cylinders shut down, but the identity of the shut-down cylinders can differ.

[0075] After the number and identity of cylinders from the first and second cylinder groups whose first exhaust valve is selectively shut off, and the duration of the shutdown, have been determined based on the fact that the turbine speed is greater than the turbine speed limit, the generator power is greater than the power limit, the generator vibration is greater than the vibration limit, and / or the component temperature is higher than the component temperature limit, the procedure can proceed to 524. In 524, the sequence can include shutting off the first exhaust valve of the cylinders from the first and second cylinder groups that are selected for shutdown.The first exhaust valve in one or more cylinders from the first and / or second cylinder group can be selectively deactivated, for example, by hydraulically actuated lift elements, a decoupling pin in the valve train, an idle mechanism, or a cam profile adjustment mechanism (CPS), where a cam profile without lift can be used for deactivated valves. In one example, the deactivation of the first exhaust valve in one or more cylinders from the first and second cylinder groups can be controlled by a cam-based VDE actuator. In another example, a single cylinder valve actuator can selectively deactivate the first exhaust valve in one or more cylinders from the first and second cylinder groups.Therefore, the deactivated first exhaust valve in one or more cylinders from the first and second cylinder groups can be held in a closed position over one stroke of the cylinder (or held in a fixed position over the stroke).

[0076] Returning to 518, if the answer to 518 is NO, i.e., if there is no difference between the actual component temperature and the component temperature limit, the procedure can proceed to 522. In 522, the procedure may include operating the engine without shutting off the blow-off valve. That is, if it is determined that the turbine speed is below the speed limit, the generator output is below the power limit, the generator vibration is below the vibration limit, and the component temperature is below the component temperature limit, then the valve shut-off to reduce exhaust energy to the turbine can be omitted, and the engine can be operated with all first valves of all engine cylinders open.In other words, the engine can be operated in a nominal mode, whereby nominal engine operation includes, for example, the initial opening of the first exhaust valve of each cylinder during an engine stroke to deliver a first portion of the exhaust energy to the turbine via the blow-off valve, and subsequently the opening of a second exhaust valve of the same cylinder during the same engine stroke to deliver a final portion of the exhaust energy to the catalytic converter. Details of nominal engine operation are provided with reference to [reference to be inserted here]. Fig. 6 discussed further.

[0077] By shutting down the first exhaust valve of cylinders from the first and second cylinder groups selected for shutdown, the amount of exhaust energy supplied to the turbine can be reduced to limit turbine overspeed conditions, maintain the desired generator output, reduce generator vibration, and decrease cylinder overheating.

[0078] In further examples, deactivating the first exhaust valve in one or more cylinders from the first and second cylinder banks can be used to accelerate the heating of the exhaust catalyst in a split-flow engine system. For instance, if the exhaust catalyst temperature falls below a certain threshold (e.g., the catalyst's activation temperature or during its warm-up phase), the first exhaust valve of all cylinders from the first and second cylinder banks can be deactivated to direct all exhaust energy to a single catalyst via a second exhaust valve. By directing all exhaust energy to the catalyst, its heating process can be accelerated.

[0079] In relation to Fig. Figure 6 presents an example of the timing control of intake and exhaust valves with respect to a piston position for an engine system comprising supplying exhaust gases from a first exhaust valve of all cylinders in a first cylinder group to a first screw of an exhaust turbine, while simultaneously supplying exhaust gases from a first exhaust valve of all cylinders in a second cylinder group to a second screw of the exhaust turbine; and supplying exhaust gases from a second exhaust valve of all cylinders in the first and second cylinder groups to an exhaust catalyst, bypassing the turbine. The first exhaust valve of cylinders in the first and second cylinder groups is also referred to in this document as the blow-off valve, and the second exhaust valve of cylinders in the first and second cylinder groups is also referred to in this document as the extraction valve.

[0080] The in Fig. The valve control shown in Figure 6 can be a valve control which can be used under engine rated operating conditions, which may include a turbine speed below a speed limit, a generator power below a power limit, a generator NVH below an NVH limit and a component temperature below a component temperature limit.

[0081] Fig. Curve 602 illustrates a crankshaft position along the X-axis in degrees of crankshaft angle. Curve 602 represents piston positions (along the Y-axis), relative to their location from top dead center (TDC) and also relative to their location within the four strokes (intake, compression, power, and exhaust) of an engine cycle.

[0082] During engine operation, each cylinder undergoes a four-stroke cycle, consisting of an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. During the intake stroke, the exhaust valves close and the intake valves open. Air is drawn into the combustion chamber through an intake port, and the piston moves toward the bottom of the cylinder to increase its volume. The position where the piston is near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber is at its largest volume) is typically referred to by those skilled in the art as bottom dead center (BDC). In this document, BDC of the intake stroke is represented as 180 degrees before top dead center (180 BTDC). During the compression stroke, the intake and exhaust valves are closed. The piston moves toward the cylinder head to compress the air in 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 generally referred to by those skilled in the art as top dead center (TDC). In this document, TDC of the compression stroke is represented as 0 degrees TDC. In a process referred to in this document as injection, fuel is injected into the combustion chamber. In a process referred to in this document 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). In this document, BDC of the power stroke (also referred to as the expansion stroke) is represented as 180 degrees past top dead center (180 degrees after TDC).The crankshaft converts this piston movement into a torque of the radial shaft. During the exhaust stroke, the exhaust valves open to release the remaining burnt air-fuel mixture into an exhaust port, and the piston returns to top dead center (TDC).

[0083] Curve 604 represents a valve timing, valve lift, and valve opening duration for a first intake valve (I1) coupled to an intake port of the engine cylinder, while curve 606 represents a valve timing, valve lift, and valve opening duration for a second intake valve (I2) coupled to the intake port of the engine cylinder. Curve 608 represents a valve timing, valve lift, and valve opening duration for the first exhaust valve (blow-off valve), coupled to a first or second exhaust port of the engine cylinder, while curve 610 represents a valve timing, valve lift, and valve opening duration for the second exhaust valve (scavenge valve), coupled to a third exhaust port of the engine cylinder.

[0084] Curve 612 represents an exhaust mass flow from the first exhaust valve to the turbine via the first or second exhaust port. For example, the peak of curve 612 may coincide with the peak of the lift curve of the first exhaust valve 608, while in an alternative example, the peak of the mass flow curve 612 may lag behind the lift curve of the first exhaust valve 608. Furthermore, curve 614 represents an exhaust mass flow from the second exhaust valve to an exhaust catalyst via the third exhaust port. The peak of the extraction mass flow curve 614 may lag behind or coincide with the peak of the lift curve of the second exhaust valve 610, depending on the engine operating conditions.

[0085] For example, the first intake valve (I1) and the second intake valve (I2) can be opened at a common time, beginning at or shortly before 360 ​​degrees BTDC and ending at or shortly after 180 degrees BTDC. Additionally, both the first and second intake valves can be open with the same stroke and for the same duration. In other examples, the timing for opening and / or closing the intake valves can be staggered, while the duration and stroke of both intake valves can be identical.

[0086] The following refers to the valve timing for the first exhaust valve. The first exhaust valve can be opened earlier in the engine cycle compared to the second exhaust valve. In other words, the opening time of the first exhaust valve can be advanced relative to the opening time of the second exhaust valve. Specifically, the first exhaust valve can be opened before 180 degrees above top dead center (BTDC), whereas the second exhaust valve can be opened at or just before 180 degrees BTDC. Thus, the first exhaust valve can be opened before the start of an exhaust stroke, just as the piston is moving towards bottom dead center (BDC) near the end of the power stroke, and close before the end of the exhaust stroke. In contrast, the second exhaust valve can be opened after the first exhaust valve has opened (e.g., at or just before the start of the exhaust stroke) and can remain open until the exhaust stroke ends or until a subsequent intake stroke begins.Additionally, the first exhaust valve can be opened with a first, smaller valve lift, while the second exhaust valve can be opened with a second, larger valve lift. While the illustrated example demonstrates different valve lifts, valve timings, and valve opening durations for the first and second exhaust valves of an engine cylinder, it is understood that in alternative embodiments, the first and second exhaust valves can have the same valve lift and / or the same valve opening duration, even though they are actuated at different times.

[0087] Opening the first exhaust valve before opening the second allows a large portion of the exhaust energy to be directed to the turbine. Furthermore, opening the second exhaust valve allows excess exhaust energy to be directed to the catalyst, reducing backpressure between the turbine inlet and the exhaust port and thus minimizing pumping losses.

[0088] In one example, the first and second exhaust valves can be coupled to an exhaust valve actuator. This actuator can be set to open the first exhaust valve at a first time and the second exhaust valve at a second time. The actuator can also be set to open the first exhaust valve with the first valve lift for a first duration, while the second exhaust valve opens with a second, different valve lift for a second duration. In another example, the cam profile of the first exhaust valve can be set to open and close the first exhaust valve to control the exhaust energy flow from an engine cylinder to the turbine.On the other hand, the cam profile of the second exhaust valve can be set so that the second exhaust valve is opened and closed to control the exhaust flow from the engine cylinder to the exhaust catalyst.

[0089] The use of different valve lifts, valve timing, and valve opening durations for the first and second exhaust valves allows for better control of the exhaust flow from the engine cylinder to the turbine and the exhaust catalyst, thereby improving engine efficiency and reducing the engine's pollutant emissions.

[0090] With reference to Fig. Figure 7 shows an exemplary process in which the first exhaust valve of cylinders from a first and second cylinder group of an engine is selectively shut off in order to control the exhaust gas mass flow to a turbine of a turbine generator (e.g. turbine generator 190 in Fig. 1A), which is located in an exhaust system of a split exhaust engine, such as engine system 10 in Fig. 1A. The sequence in Fig. 7 can be provided by placing instructions in the system in the Fig. 1A-2 according to the procedures in the Fig. 3, Fig. 4 and Fig. The process is carried out as follows: 5. Vertical markers at times t0 - t7 represent points of interest during the sequence. In all diagrams discussed below, time is plotted on the x-axis, with time increasing from left to right in each diagram.

[0091] The first diagram from the top in Fig. Figure 7 shows the turbine speed over time. The Y-axis represents the turbine speed of the turbine generator, and the turbine speed increases in the direction of the arrow on the Y-axis. Line 702 represents a constant turbine speed, and the horizontal line 704 represents a turbine speed limit.

[0092] The second diagram from the top in Fig. Figure 7 shows the generator output (voltage or current) over time. The Y-axis represents generator output, increasing in the direction of the arrow on the Y-axis. Line 706 represents a current generator output, and line 708 represents a maximum generator output.

[0093] The third diagram from the top in Fig. Figure 7 shows the generator's NVH (also referred to as generator vibration in this document) over time. The Y-axis represents the generator's NVH, and the NVH increases in the direction of the Y-axis arrow. Line 710 represents the generator's actual NVH value, and line 712 represents the generator's NVH limit.

[0094] The fourth diagram from the top in Fig. Figure 7 shows an exhaust gas mass flow into a first or second exhaust port from the first exhaust valve of one or more cylinders from the first and second cylinder groups over time. The first exhaust port receives exhaust gases from the first exhaust valve of all cylinders in the first cylinder group and delivers the exhaust gases to a first screw of an exhaust turbine. The second exhaust port receives exhaust gases from the first exhaust valve of all cylinders in the second cylinder group and delivers the exhaust gases to a second screw of the exhaust turbine. The exhaust gases flow into an exhaust catalyst after passing through the turbine. The Y-axis represents an exhaust gas mass flow through the first port, and the exhaust gas mass flow increases along the Y-axis. Line 714 represents an exhaust gas mass flow into the first port (or the second port) from the first exhaust valve of one or more cylinders from the first and second cylinder groups.

[0095] The fifth diagram from the top in Fig. Figure 7 shows the exhaust gas mass flow into a third port from a second exhaust valve for all cylinders in the first and second cylinder groups over time. The third exhaust port delivers the exhaust gases to an exhaust catalyst, bypassing the turbine. The exhaust gas mass flow is plotted on the Y-axis and increases along the Y-axis. Line 718 represents the exhaust gas mass flow into the third port from the second exhaust valve for all cylinders in the first and second cylinder groups.

[0096] The sixth diagram from the top in Fig. Figure 7 shows the total exhaust gas mass flow through a catalytic converter over time. Therefore, this diagram represents the exhaust gas flow received by each of the first, second, and third exhaust channels. The Y-axis plots the total exhaust gas mass flow through the catalytic converter, and this flow rate increases along the Y-axis. Line 720 represents the total exhaust gas mass flow through the catalytic converter.

[0097] The seventh diagram from the top in Fig. Figure 7 shows a shutdown condition (0, 1, and 2) for the first exhaust valve of one or more cylinders from the first cylinder group. A value of "0" represents a condition in which the first exhaust valve of all cylinders from the first and second cylinder groups is active. A value of "1" represents a condition in which the first exhaust valve of a single cylinder from the first and second cylinder groups is deactivated, whereas a value of "2" represents a condition in which the first exhaust valve of all cylinders from the first and second cylinder groups is deactivated. The Y-axis shows the shutdown condition of the first exhaust valve of one or more cylinders from the first and second cylinder groups. Line 722 represents a condition in which the first exhaust valve of one or more cylinders from the first and second cylinder groups is deactivated. The eighth diagram from the top in Fig. Figure 7 shows an opening condition (0 and 1) for a bypass valve over time for a bypass valve in a first and a second exhaust channel. The value "0" represents a condition in which the bypass valve of the first and second exhaust channel is closed, whereas a value "1" represents a condition in which the bypass valve is open. The opening condition for the bypass valve of the first and second exhaust channel is plotted on the Y-axis. Line 724 represents an opening condition of the bypass valve of the first and second exhaust channel.

[0098] Before t1, the engine can operate at increasing load and speed, leading to an increase in exhaust mass flow through the first, second, and third ports. Furthermore, the engine can operate with the bypass valve closed, resulting in an increased turbine speed. Between t0 and t1, the turbine speed (702) can increase, but it may remain below the speed limit (704). The increase in turbine speed can also lead to a corresponding increase in generator power (706), which, however, may remain below the limit (708). Additionally, the generator vibration (710) can remain below the vibration limit (712). Accordingly, the engine can be operated with the first exhaust valve active in all cylinders of the first and second cylinder groups.

[0099] Immediately before t1, the turbine speed (702) may exceed the speed limit (704). During this initial turbine overspeed condition, generator power and generator vibration are lower. An engine control unit may shut down a first cylinder pattern of individual first exhaust valve mechanisms of the first and second cylinder groups (722) in response to the turbine speed exceeding a speed limit at t1. In the illustrated example, the control unit may select one first cylinder from the first cylinder group and one first cylinder from the second cylinder group, and the first exhaust valve of the selected cylinders may be shut down.The first exhaust valve of the first cylinder in the first cylinder group and the first cylinder in the second cylinder group can be shut off while the cylinders continue to operate and the intake valves and the second exhaust valve continue to open and close during the engine stroke. Furthermore, the second cylinder from the first and second cylinder groups can continue to operate with its first and second exhaust valves active. Selective shut-off allows the exhaust mass flow through the first (or second) channel, which receives exhaust gases from the first exhaust valve of the first cylinder in the first (or second) cylinder group, to decrease (714). Simultaneously, the exhaust flow through the third channel, which receives exhaust gases from the second valve of the corresponding cylinders, can increase (718), thus maintaining the overall exhaust flow (720).Accordingly, the turbine speed can decrease between t1 and t2 by closing the first exhaust valve in the selected cylinders and the resulting drop in exhaust gas mass flow to the turbine. Furthermore, the generator output can be maintained to the desired extent by reducing the turbine speed, and generator vibration can also be reduced, since the turbine drives the generator.

[0100] At time t2, in response to the turbine speed (702) falling to the speed limit (704), the first exhaust valve of the first cylinder from the first cylinder group and of the first cylinder from the second cylinder group can be reactivated (722).

[0101] Between t2 and t3, due to the reactivation of the first exhaust valve of cylinders from the first and second cylinder groups, the exhaust gas flow from the first exhaust valve of all cylinders from the first and second cylinder groups to the turbine can drop, leading to a decrease in the exhaust gas mass flow to the first channel and a corresponding decrease in the exhaust gas mass flow to the third channel, while the total mass flow to a downstream catalyst remains constant.

[0102] At t3, the turbine speed again exceeds the speed limit. The increase in turbine speed at t3 is greater than the increase at t1. Furthermore, the generator output can also increase due to the turbine speed increase and exceed the power limit. Additionally, the generator vibration can exceed the vibration limit. During this second turbine overspeed condition, both the generator output and the generator vibration are higher. Consequently, an engine control unit can shut down a second cylinder pattern on individual first exhaust valve mechanisms of the first and second cylinder banks in response to the turbine speed exceeding the speed limit and the generator output exceeding the power limits.Alternatively, an engine control unit can shut down a third cylinder pattern on individual first exhaust valve mechanisms of the first and second cylinder groups in response to the turbine speed exceeding the speed limit and the generator vibration exceeding a vibration limit. For example, the first exhaust valve of a second cylinder from the first cylinder group and of a second cylinder from the second cylinder group can be shut down (722). In particular, the first exhaust valve of the second cylinder from the first cylinder group and of the second cylinder from the second cylinder group can remain shut down between t3 and t4 to reduce the exhaust flow to the twin-screw turbine. By shutting down the second cylinder from the first cylinder group and the second cylinder from the second cylinder group, the turbine speed, generator power, and generator vibration can decrease between t3 and t4.Furthermore, the exhaust mass flow through the first and second channels can decrease, while the exhaust flow through the third channel (via the second exhaust valve of the corresponding cylinders) increases proportionally to maintain a constant total exhaust flow. In this paper, the first cylinder deactivation pattern at t1 and the second or third cylinder deactivation pattern at t3 respond to different turbine overspeed conditions, with the first exhaust valves being selectively deactivated in all cases for the same number of cylinders, which, however, have different identities. In alternative examples, the second and third cylinder patterns may involve the deactivation of first exhaust valves for a larger number of cylinders due to the greater difference between the turbine speed and the speed limit.

[0103] At t4, the turbine speed can decrease but still remain above the speed limit, while the generator power and generator vibration exceed the limits. To accelerate the control of the turbine speed, generator power, and generator vibration, a bypass valve (724), coupled via the turbine, can be opened to direct the exhaust gas flow to the exhaust catalyst, bypassing the turbine. Consequently, the exhaust gas flow to the turbine can decrease, causing the turbine speed, generator power, and generator vibration to fall below their respective limits more quickly than the rate of decrease when only the first exhaust valves are closed. At t5, the turbine speed can fall below the speed limit, and the generator power and generator vibration can also fall below their limits.Accordingly, in t5, the first exhaust valve of the second cylinder from the first cylinder group and of the second cylinder from the second cylinder group can be reactivated and the overflow valve can be closed.

[0104] Between t5 and t6, the exhaust gas flow to the turbine via the first exhaust valve of all cylinders from the first and second cylinder groups can increase by reactivating the first exhaust valve of the second cylinder from the first cylinder group and the second cylinder from the second cylinder group, while the exhaust gas flow through the second valves decreases accordingly.

[0105] At t6, the turbine speed can again exceed the speed limit, causing the generator output to also exceed the power limit and the generator vibration to exceed the vibration limit. To reduce the turbine speed, generator output, and generator vibration, the first exhaust valve of all cylinders in the first and second cylinder groups can be shut off at t6 (722), resulting in a large drop in exhaust mass flow through the first or second channel and a larger increase in exhaust flow through the third channel. By shutting off the blow-off valve at t6, the turbine speed, generator output, and generator vibration can decrease between t6 and t7.In this document, a greater increase in turbine speed than the increase in turbine speed at t1 and t3 allows the first exhaust valve of all cylinders from the first and second cylinder groups to remain closed for a longer period in order to reduce the exhaust gas flow to the turbine and thereby the turbine speed, generator power and generator vibration.

[0106] At t7, the turbine speed can fall below the speed limit, the generator output below the power limit, and the generator vibration below the vibration limit. Accordingly, the first exhaust valve in all cylinders of the first and second cylinder groups can be reactivated. In other words, the engine can resume rated operation with all valves active and exhaust gases supplied by the first and second exhaust valves of each cylinder in a cylinder group. Specifically, rated operation can include operating the first exhaust valve of each of the first and second cylinders in a cylinder group with an advance in the opening time of the first exhaust valve relative to the opening time of the second exhaust valve of each of the first and second cylinders.Furthermore, for nominal operation, the first exhaust valve of each cylinder in both the first and second cylinder groups can be operated with an advanced closing time relative to the closing time of the second exhaust valve of each cylinder in both the first and second cylinder groups. By opening the second exhaust valve later during the exhaust stroke, the cylinder pressure can be reduced from a higher back pressure before the turbine inlet to a lower pressure after the turbine. Consequently, pumping losses can be reduced.

[0107] Improved engine operation can be achieved by shutting off the first exhaust valve of one or more cylinders from the first and second cylinder banks when the difference between the turbine speed and the speed limit is small, or when the turbine speed exceeds the speed limit for a shorter period. By shutting off the first exhaust valve of each cylinder from the first and second cylinder banks when the difference between the turbine speed and the speed limit is larger, or when the turbine speed exceeds the speed limit for a longer period, turbine speed control can be improved while maintaining generator output at the desired levels and reducing NVH (noise, vibration, and harshness) problems associated with vibrations at a generator driven by the turbine.

[0108] For example, an inline engine may have four cylinders, which are divided into cylinder groups, each consisting of two cylinders and each cylinder having a single first exhaust valve. In this document, if the difference between the turbine speed and the turbine speed limit is greater than the first limit, a single cylinder from the first cylinder group and a single cylinder from the second cylinder group may be selected, and the first exhaust valve of the selected cylinders may be deactivated. The single cylinder from the first cylinder group and the single cylinder from the second cylinder group may be selected based on their position along an engine block and / or their firing order.

[0109] In another example with a similar engine configuration, if the difference between the generator vibration and the vibration limit is greater than the difference limit, both cylinders from the first cylinder group and both cylinders from the second cylinder group can be selected, and the first exhaust valve of all selected cylinders can be shut off. In this example, the first exhaust valve of all cylinders can be shut off while the cylinders continue to operate, and the intake valves and the second exhaust valve continue to open and close during the engine stroke.

[0110] By shutting off the first exhaust valve of selected cylinders from the first and second cylinder groups due to the turbine speed being greater than the turbine speed limit, the generator power being greater than the power limit, and the generator vibration being greater than the vibration limit, the turbine overspeed and the increase in generator vibration can be reduced while maintaining the desired generator power, thereby improving engine performance.

[0111] With reference to Fig. Figure 8 shows a graphic illustrating the operation of a first exhaust valve from one or more cylinders of a first and a second cylinder group to direct the flow of exhaust energy to a turbine of a turbine generator (e.g., turbine generator 190 in Fig. 1A), which is located in an exhaust system of a split exhaust engine, such as engine system 10 in Fig. 1A, to adapt. The sequence in Fig. 8 can be provided by placing instructions in the system into the Fig. 1A - 2 according to the procedures in the Fig. Steps 3-5 are executed. Vertical markers at times t0-t8 represent points of interest during the sequence. In all diagrams discussed below, time is plotted on the x-axis, with time increasing from left to right in each diagram.

[0112] The first diagram from the top in Fig. Figure 8 shows an engine load over time. The engine load is plotted on the Y-axis and increases along the Y-axis. Line 802 represents an actual engine load, and horizontal line 804 represents a first engine load limit, while horizontal line 806 represents a second engine load limit.

[0113] The second diagram from the top in Fig. Figure 8 shows a shutdown condition (0 and 1) over time for the first exhaust valve of the first and second cylinders of the first cylinder group. The value "0" represents a condition in which the first exhaust valve of the first and second cylinders of the first cylinder group is not shut off. The value "1" represents a condition in which the first exhaust valve of a single cylinder from the first cylinder group is shut off. The Y-axis shows a shutdown condition in which the first exhaust valve of a single cylinder from the first cylinder group is shut off. Line 808 represents a condition in which the first exhaust valve of a single cylinder from the first cylinder group is shut off.

[0114] The third diagram from the top in Fig. Figure 8 shows a shutdown condition (0 and 1) over time for the first exhaust valve of the first and second cylinders of a second cylinder group. The value "0" represents a condition in which the first exhaust valve of the first cylinder and the second cylinder of the second cylinder group is not shut off. The value "1" represents a condition in which the first exhaust valve of a single cylinder from the second cylinder group is shut off. The Y-axis shows a shutdown condition in which the first exhaust valve of a single cylinder from the second cylinder group is shut off. Line 810 represents a condition in which the first exhaust valve of a single cylinder from the second cylinder group is shut off.

[0115] The fourth diagram from the top in Fig.Figure 8 shows a component temperature over time. The component temperature is plotted on the Y-axis and increases in the direction of the Y-axis. Line 812 represents the component temperature.

[0116] Between t0 and t1, the engine can run at an engine load (802) below a first engine load limit (804). The component temperature (812) increases due to the increasing engine load, while remaining below a component temperature limit (814). Therefore, it is not necessary to shut off the first exhaust valve of any cylinder (from the first or second cylinder group) to reduce the component temperature. Consequently, the engine can be operated without shutting off the blow-off valve.

[0117] At time +t1, while the engine is running below the first engine load limit (804), the component temperature (812) can reach the component temperature limit (814). Accordingly, to reduce cylinder overheating, the first exhaust valve of the first cylinder in the first cylinder group can be deactivated at t1 (808), while the first exhaust valve of the second cylinder in the first cylinder group can remain active. By deactivating the first exhaust valve of the first cylinder in the first cylinder group, the component temperature begins to decrease, but remains above the component temperature limit (814). In response to the increased component temperature and the associated increase in engine load above the second engine load limit (806) (indicating a further tendency for the cylinder to heat up), the first exhaust valve of the first cylinder in the second cylinder group is also deactivated at t2.In particular, the first exhaust valve of the first cylinder in both the first and second cylinder groups can remain closed, while the first exhaust valve of the second cylinder in both the first and second cylinder groups remains open. The first exhaust valve of the first cylinder in the first cylinder group and the first cylinder in the second cylinder group can be closed while the cylinders continue to operate and the intake valves and the second exhaust valve continue to open and close during the engine cycle. Due to the closure of the first exhaust valve of multiple cylinders, the component temperature begins to decrease.

[0118] At t3, the engine load (802) drops to the second engine load limit (806), while the component temperature remains above the component temperature limit. In response to the decrease in engine load, the first exhaust valve of the first cylinder from the second cylinder group (810) is reactivated at t3, while the first exhaust valve of the first cylinder from the first cylinder group (808) remains deactivated to reduce the component temperature.

[0119] Between t3 and t4, the engine load (802) drops to the first engine load limit (804) and the component temperature falls to the component temperature limit. Accordingly, at t4, the first exhaust valve of the first cylinder from the first cylinder group (808) is reactivated.

[0120] Between t4 and t5, the engine load can decrease further to a value below the first engine load limit, and the component temperature can remain below the component temperature limit. Accordingly, the first exhaust valve of all cylinders from the first and second cylinder groups can remain active.

[0121] Subsequently, at time t5, the engine load (802) can again rise to the first engine load limit (804). Due to the increase in engine load, the component temperature can also rise and exceed the component temperature limit. In response to the cylinder heating, at t5 the first exhaust valve of the second cylinder from the second cylinder group (810) can be deactivated to reduce cylinder overheating. Between t5 and t6, the engine load (802) can continue to rise, exceeding the first engine load limit (804), but remaining below the second engine load limit (806) until shortly before t6. As a response to the increase in engine load, the component temperature can also rise, while remaining above the component temperature limit. Accordingly, at t6 the first exhaust valve of the second cylinder from the first cylinder group (808) can also be deactivated to further reduce the increase in component temperature.

[0122] Between t6 and t7, the engine load can increase. However, by maintaining the deactivation of the first exhaust valve of the second cylinder from both the first and second cylinder groups, the component temperature is reduced and overheating is prevented.

[0123] At t7, the first exhaust valve of the first cylinder from the first cylinder group (808) is reactivated in response to a drop in component temperature. However, because the engine load is above the first engine load limit, the first exhaust valve of the second cylinder from the second cylinder group (810) can remain deactivated to further reduce component heating caused by the higher engine load.

[0124] At time t8, the first exhaust valve of the second cylinder from the second cylinder group (810) can be reactivated because the engine load has fallen below the first engine load limit and the component temperature has fallen below the component temperature limit. In other words, the engine can return to rated operation without deactivating the blow-off valve. Specifically, rated operation can include supplying exhaust gases from the first exhaust valve of each of the first and second cylinders and operating the first exhaust valve of each of the first and second cylinders with an opening time advanced relative to the opening time of a second exhaust valve of each of the first and second cylinders.Furthermore, nominal operation may include the supply of exhaust gases from the first exhaust valve and the operation of the first exhaust valve of each cylinder from the first cylinder group and the second cylinder group with a closing time of the first exhaust valve that is advanced with respect to a closing time of a second exhaust valve of each cylinder from the first cylinder group and from the second cylinder group.

[0125] By selectively shutting off an exhaust valve on one or more cylinders coupled to a channel that directs exhaust gases to a turbine screw, the turbine speed can be rapidly controlled. Specifically, by adjusting the number and identity of the cylinders in cylinder groups used for selective exhaust valve shut-off, the exhaust mass flow to a downstream turbine can be varied to provide different flow ranges. Additionally, selecting cylinders based on their grouping can reduce NVH (noise, vibration, and harshness) problems caused by excessively high turbine speeds. For example, vibrations felt at a generator driven by the turbine can be reduced.By keeping one or more exhaust valves active, with this remaining exhaust valve, coupled to a channel, directing the exhaust gases to an exhaust catalyst while bypassing the turbine, the catalyst temperature can be controlled simultaneously with the turbine speed. This reduces turbine overspeed, increases in generator NVH (noise, vibration, and harshness), and excessive component temperatures, thereby improving engine performance.

[0126] In one example, a method for an engine comprises supplying exhaust gases from a first exhaust valve of all cylinders in a first cylinder group to a first screw of an exhaust turbine, while simultaneously supplying exhaust gases from a first exhaust valve of all cylinders in a second cylinder group to a second screw of the exhaust turbine; and supplying exhaust gases from a second exhaust valve of all cylinders in the first and second cylinder groups to an exhaust catalyst, bypassing the turbine. The foregoing example may additionally or optionally include the selective shut-off of the first exhaust valve of one or more cylinders in the first and second cylinder groups in response to a turbine speed exceeding a limit speed. In one or all of the foregoing examples, the turbine additionally or optionally drives a generator.One or all of the foregoing examples may additionally or optionally include the selection of one or more from a series of first exhaust valves for shutdown and a duration of selective shutdown based on the turbine speed. In one or all of the foregoing examples, additionally or optionally, one or more of the series of first exhaust valves selected for shutdown, the sequence of selective shutdown, and the duration of selective shutdown are also selected based on the generator voltage or generator current relative to a power limit, or the generator vibration relative to a vibration limit.

[0127] In one or all of the preceding examples, additionally or optionally, one or more of the series of first exhaust valves selected for shutdown, the sequence of selective shutdown, and the duration of selective shutdown are also selected based on an exhaust system temperature relative to a temperature limit. In one or all of the preceding examples, additionally or optionally, the first exhaust valve of all cylinders from the first cylinder group is coupled to the first turbine screw via a first exhaust manifold, and the first exhaust valve of all cylinders from the second cylinder group is coupled to the second turbine screw via a second, different exhaust manifold, wherein the second exhaust valve of all cylinders from the first and second cylinder groups is coupled to the exhaust catalyst via a third exhaust manifold, bypassing the turbine.In one or all of the above examples, the first cylinder group is additionally or optionally located on a first side of the engine, and the second cylinder group is located on a second, different side of the engine. In one or all of the above examples, the first and second cylinder groups are additionally or optionally selected based on the cylinder position along an engine block or a firing order.

[0128] Furthermore, in one or all of the above examples, the following are additionally included, or where appropriate, for selection based on turbine speed: the shutting off of the first exhaust valve of a cylinder from the first and second cylinder groups if the difference between the turbine speed and the speed limit is smaller, or if the turbine speed falls below the speed limit for a shorter period; and the shutting off of the first exhaust valve of each cylinder from the first and second cylinder groups if the difference between the turbine speed and the speed limit is larger, or if the turbine speed exceeds the speed limit for a longer period.In one or all of the above examples, selecting based on exhaust system temperature additionally or optionally includes selectively shutting off the first exhaust valve of all cylinders in the first and second cylinder groups in response to the exhaust system temperature falling below the temperature limit. In one or all of the above examples, supplying exhaust gases from the first exhaust valve additionally or optionally includes operating the first exhaust valve of each of the first and second cylinders with an opening time of the first exhaust valve that is advanced with respect to the opening time of a second exhaust valve of each of the first and second cylinders.In one or all of the above examples, supplying exhaust gases from the first exhaust valve additionally or, where appropriate, also includes operating the first exhaust valve of each cylinder from the first cylinder group and the second cylinder group with a closing time of the first exhaust valve that is advanced with respect to the closing time of a second exhaust valve of each cylinder from the first cylinder group and the second cylinder group.

[0129] In another example, a method for an engine may include the flow of exhaust gases from a first exhaust valve of all cylinders of a first cylinder group to a first screw of an exhaust turbine; the flow of exhaust gases from a first exhaust valve of all cylinders of a second cylinder group to a second screw of the exhaust turbine, the turbine driving a generator; the flow of exhaust gases from a second exhaust valve of all cylinders of the first and second cylinder groups to an exhaust catalyst, bypassing the turbine; and the deactivation of a first cylinder pattern at individual first exhaust valve mechanisms of the first and second cylinder groups in response to the turbine speed being higher than a speed limit during a first operating condition; and the deactivation of a second, different cylinder pattern at individual first exhaust valve mechanisms of the first and second cylinder groups in response to this.that the turbine speed during a second operating condition, where the second operating condition differs from and is mutually exclusive with the first, is higher than the speed limit. The foregoing example may additionally or optionally include each of the first and second patterns, based on one or more of the following: turbine speed, engine speed, engine load,Engine temperature and gear engaged. In one or all of the preceding examples, the first cylinder pattern additionally or optionally includes a first cylinder from the first cylinder group and a first cylinder from the second cylinder group, and the second cylinder pattern includes a second cylinder from the first cylinder group and a second cylinder from the second cylinder group. In one or all of the preceding examples, the deactivation of the first cylinder pattern additionally or optionally includes the selective deactivation of individual first exhaust valve mechanisms from one or more cylinders solely from the first cylinder group when the engine load is higher, and the selective deactivation of individual first exhaust valve mechanisms from one or more cylinders from both the first and second cylinder groups.when the engine load is lower. One or all of the above examples may additionally or as appropriate include the deactivation of the second cylinder pattern, which involves the selective deactivation of individual first exhaust valve mechanisms from one or more cylinders only from the first cylinder group when the engine speed is higher, and the selective deactivation of individual first exhaust valve mechanisms from one or more cylinders from both the first and second cylinder groups when the engine speed is lower.

[0130] Another exemplary engine system includes: an engine comprising an exhaust manifold with an exhaust catalyst; an exhaust turbine with a first and a second screw, the turbine driving a generator; a first cylinder group comprising a first cylinder, the first cylinder comprising a first and a second exhaust valve, the first exhaust valve being selectively shut off; a second cylinder group comprising a second cylinder, the second cylinder comprising a first and a second exhaust valve, the first exhaust valve being selectively shut off; a first channel coupling the first exhaust valve of the first cylinder to a first screw of the turbine; a second channel coupling the first exhaust valve of the second cylinder to the second screw of the turbine;A third channel, which couples the second exhaust valve of each of the first and second cylinders to an exhaust catalyst, thereby bypassing the turbine, with the exhaust catalyst being located downstream of the turbine; and a control unit. The control unit can be configured with computer-readable instructions stored in non-volatile memory, which serve to: operate in a first mode with the first exhaust valve of the first and second cylinders activated; operate in a second mode with the first exhaust valve of one of the first and second cylinders deactivated; operate in a third mode with the first exhaust valve of each of the first and second cylinders deactivated;and to switch between modes based on the exhaust system temperature and / or the turbine speed. In the above example, the transition includes moving from the first mode to the second mode in response to one or more of the following: an increase in the exhaust system temperature below a threshold, an increase in the turbine speed below a threshold; and moving from the first mode to the third mode in response to one or more of the following: an increase in the exhaust system temperature above a threshold, an increase in the turbine speed above a threshold, and wherein the second exhaust valve is active during the first, second, and third modes.

[0131] It should be noted that the exemplary control and estimation sequences contained in this document can be used with various engine and / or vehicle system configurations. The control methods and sequences disclosed in this document can be stored as executable instructions on non-volatile memory and executed by the control system, which includes the control unit in combination with the various sensors, actuators, and other engine hardware. The specific sequences described in this document can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. Therefore, various illustrated actions, processes, and / or functions can be performed in the illustrated sequence or in parallel, or in some cases, omitted.Similarly, the processing sequence is not necessarily required to achieve the features and advantages of the exemplary embodiments described in this document, but is provided for the sake of clarity and description. One or more of the illustrated actions, processes, and / or functions can be performed repeatedly, depending on the specific strategy employed. Furthermore, the described actions, processes, and / or functions can graphically represent code to be programmed onto non-volatile memory of the computer-readable storage medium in the engine control system. The described actions are then performed by executing the instructions in a system that includes the various engine hardware components in combination with the electronic control unit.

Claims

[1] Method for an engine (10), comprising: Supplying exhaust gases from a first exhaust valve (E1) of all cylinders (20) from a first cylinder group to a first screw of an exhaust gas turbine (92), while simultaneously supplying exhaust gases from a first exhaust valve (E1) of all cylinders (20) from a second cylinder group to a second screw of the exhaust gas turbine (92); Supplying exhaust gases from a second exhaust valve (E2) of all cylinders (20) from the first and second cylinder groups to an exhaust catalyst (72), bypassing the exhaust turbine (92); and selective shut-off of at least one first exhaust valve (E1) of at least one cylinder (20) selected from the first and second cylinder groups in response to the fact that a turbine speed of the exhaust turbine (92) exceeds a threshold speed. [2] Method according to claim 1, wherein the exhaust gas turbine (92) drives a generator (94). [3] Method according to claim 1, wherein the selective deactivation of at least one first exhaust valve (E1) of at least one cylinder selected from the first and second cylinder groups (20) further selection a sequence of selective deactivation of at least the first exhaust valve (E1) of at least one cylinder (20) selected from the first and second cylinder groups and a duration of selective shutdown of at least the first exhaust valve (E1) of at least one cylinder (20) selected from the first and second cylinder groups based on the turbine speed. [4] Method according to claim 3, wherein the exhaust gas turbine (92) drives a generator and selectively shutting down at least one first exhaust valve (E1) of at least one cylinder selected from the first and second cylinder groups (20), the sequence of selective deactivation of at least the first exhaust valve (E1) of at least one cylinder (20) selected from the first and second cylinder groups and the duration of the selective shutdown of at least the first exhaust valve (E1) of at least one cylinder selected from the first and second cylinder groups (20) in addition based on a generator output in relation to a power threshold or on a generator current in relation to a current threshold. [5] Method according to claim 3, wherein selectively shutting down at least one first exhaust valve (E1) of at least one cylinder selected from the first and second cylinder groups (20), the sequence of selective deactivation of at least the first exhaust valve (E1) of at least one cylinder (20) selected from the first and second cylinder groups and the duration of the selective shutdown of at least the first exhaust valve (E1) of at least one cylinder selected from the first and second cylinder groups (20) in addition based on an exhaust system temperature in relation to a temperature threshold. [6] Method according to claim 1, wherein the first exhaust valve (E1) of all cylinders (20) from the first cylinder group is coupled to the first screw of the exhaust turbine (92) via a first exhaust manifold and the first exhaust valve (E1) of all cylinders (20) from the second cylinder group is coupled to the second screw of the exhaust turbine (92) via a second, different exhaust manifold, and wherein The second exhaust valve (E2) of all cylinders (20) from the first and second cylinder group is coupled to the exhaust catalyst (72) via a third exhaust manifold, bypassing the exhaust turbine (92). [7] Method according to claim 1, wherein the at least one first exhaust valve (E1) of the at least one cylinder (20) selected from the first cylinder group and the second cylinder group is selected based on a cylinder position along an engine block or a firing order. [8] Method according to claim 1, wherein the selective shut-off of at least one first exhaust valve (E1) of at least one cylinder (20) selected from the first and second cylinder group in response to the fact that a turbine speed of the exhaust turbine (92) exceeds a threshold speed comprises: Shutting down the first exhaust valve (E1) of a cylinder (20) of the first and second cylinder groups when a difference between the turbine speed and the threshold speed is greater than a first threshold value and Shutting down the first exhaust valve (E1) of each cylinder (20) of the first and second cylinder group when the difference between the turbine speed and the threshold speed is greater than a second threshold, where the second threshold is greater than the first threshold. [9] Method according to claim 1, wherein supplying exhaust gases from the first exhaust valve (E1) includes operating the first exhaust valve (E1) of each of the first cylinders (20) and the second cylinders (20) with an opening time of the first exhaust valve (E1) that is advanced with respect to the opening time of a second exhaust valve (E2) of each of the first and second cylinders (20). [10] Method according to claim 5, wherein selectively shutting down at least one first exhaust valve (E1) of at least one cylinder selected from the first and second cylinder groups (20), the sequence of selectively shutting down at least one first exhaust valve (E1) and at least one cylinder (20) selected from the first and second cylinder groups and the duration of the selective shutdown of at least the first exhaust valve (E1) of at least one cylinder selected from the first and second cylinder groups (20) based on the exhaust system temperature in addition selectively shutting off the first exhaust valve (E1) of each cylinder (20) of the first and second cylinder groups in response to the exhaust system temperature being lower than the temperature threshold.

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