METHOD AND SYSTEMS FOR ADAPTING A DIRECT FUEL INJECTION DEVICE

Abstract

Methods for an internal combustion engine, comprising: Delivering fuel to one cylinder in a combustion cycle as multiple direct injections; and In response to the fact that a fuel mass from one of the multiple direct injections is located in a transition region of a direct injection device map, updating one or more of a ratio of fuel delivered in each of the multiple direct injections and a number of multiple injections to move the fuel mass of one of the multiple direct injections out of the transition region.

Description

Area

[0001] The present description generally relates to methods and systems for adapting the operation of a direct fuel injection device for an internal combustion engine. General state of the art / Summary

[0002] Internal combustion engines can utilize direct fuel injection, where fuel is injected directly into a combustion engine cylinder to improve mixture formation and reduce cylinder charge temperatures. This can be used instead of, or in addition to, port fuel injection, where fuel is injected into an intake port upstream of an intake valve of a combustion engine cylinder. The duration for which a direct fuel injection device is active (the direct injection pulse width) can depend on the fuel pressure supplied to the injection device, the engine speed, and the engine load. To fully exploit the benefits of direct injection, it can be advantageous to have complete control over the pulse width range of the direct fuel injection system.This includes a wide range of operating conditions, including, but not limited to, fuel distributor pressure, internal combustion engine speeds, and bulk fuel flow.

[0003] The performance of magnetically controlled direct fuel injectors can, however, exhibit a limitation in their flow characteristics between the ballistic and stroke regions. This region is typically referred to as the transition region of the direct fuel injector. In this region, the fuel injector's flow rate is imprecise and unpredictable, resulting in shot-to-shot and part-to-part variability. For example, the direct fuel injector may deliver more or less fuel than desired in the transition region. Furthermore, the variability in the transition region can exhibit a linear tendency, making it difficult to learn and compensate for the variability.Fuel injection variability can cause cylinder torque output imbalances due to the varying amount of fuel injected into each cylinder. It can also lead to higher tailpipe emissions and reduced fuel efficiency due to an inability to accurately meter the fuel injected into each cylinder. As a result, there may be internal combustion engine operating ranges where the direct fuel injection system cannot adequately meet NVH, drivability, and emissions requirements.

[0004] Several approaches to reducing direct injection device variability have been developed. One exemplary approach is presented by Ranga et al. in US 2016 / 0153391A1. In this approach, a direct fuel injection is split into multiple injections, one of which has a pulse width small enough to be delivered within the ballistic region of the direct injection device. A transfer function of the injection device is learned based on a lambda value and a split ratio. A subsequent direct injection is then adapted based on the learned transfer function.

[0005] DE 10 2012 205 839 A1 and DE 10 2010 040 283 B3 describe further methods and systems for adapting a direct fuel injection device.

[0006] The inventors of the present invention have recognized potential problems with the approach described in Patent 391 and other related approaches. For example, the variability of the fuel injection device in the transition region remains unassigned. The various approaches update the transfer function based on learned fuel injection device variability in the ballistic region, where the fuel injection device pulse width is smaller than in the transition region. However, fuel delivery errors may still exist for larger injection pulse widths outside the ballistic region, but smaller than those within the stroke region. As a result, NVH, drivability, and emissions problems may persist. For example, increasing the electrical pulse width for the fuel injection device in the ballistic region increases the amount of mass delivered.Although some variability may exist during the rise, this variability can be learned, and the shape or shift of the rise in the ballistic region can be adjusted to accommodate it. However, in the transition region, an increased pulse width can actually lead to a reduction in the injected fuel mass. Consequently, it may be impossible to simply shift and reshape the rise in the transition region. The variability is exacerbated because the rise in the transition region differs for each injection device and varies significantly from shot to shot. The object of the present invention is therefore to counteract the aforementioned problems, at least in part. This object is achieved by the features of the independent claims. Advantageous embodiments of the invention are described in the dependent claims.

[0007] In one example, the problems described above can be addressed by a method for an internal combustion engine that includes: delivering fuel to a cylinder in a combustion cycle as multiple direct injections; and, in response to a fuel mass from one of the multiple direct injections being located in a transition region of a direct injection device map, updating one or more of the ratios of fuel delivered in each of the multiple direct injections and the number of multiple injections to move the fuel mass of one of the multiple direct injections out of the transition region. In this way, the variability of the direct injection device in the transition region can be addressed.

[0008] As an example, an internal combustion engine control unit can determine an initial fuel injection profile based on internal combustion engine operating conditions. This can include, for example, a total fuel mass to be delivered via direct injection, the number of direct injections required to deliver the total fuel mass (e.g., 2-4 injections), and a split ratio among the multiple direct injections. The split ratio can be the ratio of the portion of the total fuel mass to be delivered via the first of the multiple direct injections relative to the portion of the total fuel mass to be delivered via a second (third, etc.) of the multiple direct injections.A fuel injection pulse width to be commanded is then determined based on the split ratio, including the fuel mass to be delivered in each of the multiple injections, as well as the fuel rail pressure. If it is determined that the pulse width for any of the injections lies within the transition region of the direct injection system, the control unit can update the injection profile to operate outside the transition region. Specifically, the control unit can modify the fuel mass delivered to each injection based on its position within the transition region and its distance from the boundary of the ballistic and stroke regions, thereby updating the split ratio.For example, the fuel mass of an injection near the ballistic region can be reduced to shift the injection from the transition region to the ballistic region. Conversely, the fuel mass of an injection near the lift region can be increased to shift the injection from the transition region to the lift region. Therefore, the fuel mass of all injections can be adjusted to maintain the overall fuel mass.

[0009] In other examples, the number of injections within a split injection sequence can be updated additionally or optionally. For instance, if the pulse width of at least one of the multiple direct injections lies within the transition region, the number of injections can be reduced. By combining the fuel mass from two or more injections, the pulse width can be moved into the full-stroke region (linear region). As another example, if the pulse width of a single direct injection lies within the transition region, the number of injections can be increased. By splitting the fuel mass into two or more injections, the pulse width of one injection can be moved into the full-stroke region, while the pulse width of another injection can be moved into the ballistic region.Furthermore, for internal combustion engines configured with both direct and port injection, the ratio of the total fuel mass delivered via direct injection to port injection can be updated. In other scenarios, a combination of the aforementioned approaches may be selected. This selection can be based on internal combustion engine operating conditions, such as engine speed and NVH (noise, vibration, and harshness) restrictions.

[0010] This reduces the variability of a direct injection system. The technical effect of adjusting the direct injection fuel mass based on the injection pulse width position on a map of the direct injection system's operating regions is that the direct injection system cannot be operated at pulse widths where non-linear fuel injection behavior occurs. Simultaneously, a consistent overall fuel mass can be maintained. As a result of operating outside the direct injection system's transition region, combustion engine air-fuel ratio and torque errors can be reduced. Furthermore, this approach can reduce combustion engine emissions and NVH (noise, vibration, and harshness). Overall drivability is improved.

[0011] It will be understood that the foregoing summary is provided to present, in simplified form, a selection of concepts that are described in more detail in the full description. It is not intended to identify important or essential features of the claimed subject matter, the scope of which is defined solely by the claims following the full description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages mentioned above or in any part of this disclosure. Brief description of the drawings Fig. Figure 1 is a schematic representation of an internal combustion engine system. Fig. Figure 2 shows a high-level flowchart of an exemplary procedure for adapting a fuel injection profile to move direct injection device operation out of a transition region. Fig. Figure 3 shows a high-level flowchart of an exemplary procedure for updating a direct injection fuel mass to move the direct injection device operation out of the transition region. Fig. Figure 4 shows an example direct injection device performance map. The Fig. Figures 5-6 show an example of operating a direct injection device outside the transition region by adapting a number of direct injection devices. The Fig. Figures 7-8 show an example of operating a direct injection device outside the transition region by adjusting the fuel mass of each injection of multiple direct injections. The Fig. Figures 9-10 show an example of operating a direct injection device outside the transition region by adjusting the ratio of fuel delivered via direct injection relative to port injection. Fig. Figure 11 shows exemplary fuel injection profiles that can be used to operate a direct injection device outside the transition region. Detailed description

[0012] The following description concerns systems and methods for improving direct injection device performance in an internal combustion engine system, such as the internal combustion engine system from Fig. 1. The internal combustion engine can be operated via a control system according to a control routine, such as the exemplary procedure from the Fig. 2-3, to operate the direct fuel injection device outside a transition region ( Fig. 4), in which the variability of the injection device is high. A fuel injection profile can be updated by adjusting one or more of the port-injected fuel to direct-injected fuel split ratios, the number of direct injections, and the direct-injected fuel split ratio ( Fig. 5-11).

[0013] Fig. Figure 1 represents an example of a combustion chamber or cylinder of an internal combustion engine 10 coupled to a vehicle 5. In some examples, the vehicle 5 may be a hybrid vehicle with multiple torque sources available to one or more vehicle wheels 55. In other examples, the vehicle 5 is a conventional vehicle with only an internal combustion engine or an electric vehicle with only one electric machine. In the example shown, the vehicle 5 includes an internal combustion engine 10 and an electric machine 52. The electric machine 52 may be an electric motor or an electric motor / generator. The crankshaft 140 of the internal combustion engine 10 and the electric machine 52 are connected to the vehicle wheels 55 via the transmission 54 when one or more clutches 56 are engaged.In the illustrated example, a first clutch 56 is provided between the crankshaft 140 and the electric machine 52, and a second clutch 56 is provided between the electric machine 52 and the transmission 54. The controller 12 can send a signal to an actuator of each clutch 56 to engage or disengage the clutch, thereby connecting or disconnecting the crankshaft 140 from the electric machine 52 and its associated components, and / or connecting or disconnecting the electric machine 52 from the transmission 54 and its associated components. The transmission 54 can be a manual transmission, a planetary gear system, or another type of transmission. The powertrain can be configured in various ways, including as a parallel, in-line, or in-line-parallel hybrid vehicle.

[0014] The electric machine 52 receives electrical power from a traction battery 58 to provide torque to the vehicle wheels 55. The electric machine 52 can also be operated as a generator to provide electrical power for charging the battery 58, for example, during braking.

[0015] The internal combustion engine 10 can be controlled, at least partially, by a control system comprising a controller 12 and by input from a vehicle operator 130 via an input device 132. In this example, the input device 132 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. The cylinder (here also referred to as the "combustion chamber") 14 of the internal combustion engine 10 can contain combustion chamber walls 136 in which a piston 138 is arranged. The piston 138 can be coupled to the crankshaft 140 so that a reciprocating motion of the piston is translated into a rotational motion of the crankshaft. The crankshaft 140 can be coupled to at least one drive wheel of the passenger car via a transmission system. Furthermore, a starter (not shown) can be coupled to the crankshaft 140 via a flywheel to enable the starting of the internal combustion engine 10.

[0016] Cylinder 14 can draw in intake air via a series of intake air ducts 142, 144, and 146. Intake air duct 146 can communicate with other cylinders of the internal combustion engine 10 in addition to cylinder 14. In some examples, one or more of the intake ducts may include a charging device, such as a turbocharger or a supercharger. For example, the internal combustion engine 10 is shown in the illustration in Fig. 1 is configured with a turbocharger comprising a compressor 174 located between intake ports 142 and 144, and an exhaust turbine 176 located along an exhaust port 148. The compressor 174 can be powered, at least partially, via a shaft 180 through the exhaust turbine 176 when the charging device is configured as a turbocharger. In other examples, such as when the internal combustion engine 10 is equipped with a supercharger, the exhaust turbine 176 can be optionally omitted, with the compressor 174 being driven by mechanical inputs from an electric motor or the internal combustion engine. A throttle 162, comprising a throttle valve 164, can be provided along an intake port of the internal combustion engine to vary the flow rate and / or pressure of the intake air supplied to the internal combustion engine cylinders.For example, the throttle 162 can be positioned downstream of the compressor 174, as shown in . Fig. 1 shown, or alternatively it can be provided upstream of compressor 174.

[0017] The exhaust duct 148 can receive exhaust gases from other cylinders of the internal combustion engine 10 in addition to those from cylinder 14. The exhaust gas sensor 128 is shown coupled to the exhaust duct 148 upstream of the emission control device 178. The sensor 128 can be selected from various suitable sensors to provide an indication of the air-fuel ratio of the exhaust gas, such as a linear lambda sensor or UEGO sensor (universal exhaust gas oxygen sensor; wide-range or broadband lambda sensor), a binary lambda sensor or EGO sensor (as shown), a HEGO sensor (heated EGO sensor), a NOx, HC, or CO sensor. The emission control device 178 can be a three-way catalyst (TWC), a NOx trap, various other emission control devices, or combinations thereof.

[0018] Each cylinder of the internal combustion engine 10 can include one or more intake valves and one or more exhaust valves. For example, cylinder 14, as shown, has at least one intake control valve 150 and at least one exhaust control valve 156, which are arranged in an upper region of cylinder 14. In some embodiments, each cylinder of the internal combustion engine 10, which includes cylinder 14, can have at least two intake control valves and at least two exhaust control valves, which are arranged in an upper region of the cylinder.

[0019] The inlet valve 150 can be controlled by the controller 12 via the actuator 152. Similarly, the exhaust valve 156 can be controlled by the controller 12 via the actuator 154. Under certain conditions, the controller 12 can vary the signals provided to the actuators 152 and 154 to control the opening and closing of the respective inlet and exhaust valves. The position of the inlet valve 150 and exhaust valve 156 can be determined by appropriate valve position sensors (not shown). The valve actuators can be of the electric type, the cam type, or a combination thereof. The inlet and exhaust valve actuation can be controlled simultaneously, or any of the following options can be used: variable inlet cam actuation, variable exhaust cam actuation, dual independent variable cam actuation, or fixed cam actuation.Each cam actuation system can include one or more cams and use one or more cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT), and / or variable valve lift (VVL) systems, which can be operated by the control unit 12, to vary the valve operation. For example, cylinder 14 can alternatively include an intake valve controlled by an electronic valve actuation system and an exhaust valve controlled by a cam actuation system, including CPS and / or VCT. In other examples, the intake and exhaust valves can be controlled by a common valve actuator or actuation system, or by a variable valve timing actuator or actuation system.

[0020] Cylinder 14 can have a compression ratio that is the volume ratio between piston 138 at bottom dead center and at top dead center. In one example, the compression ratio is in the range of 9:1 to 10:1. However, in some examples where different fuels are used, the compression ratio can be higher. 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 using direct injection due to its effect on internal combustion engine knock.

[0021] In some examples, each cylinder of the internal combustion engine 10 may include a spark plug 192 to initiate combustion. The ignition system 190 can provide a spark to the combustion chamber 14 via the spark plug 192 in response to a spark advance signal SA from the control unit 12 under selected operating modes. However, in some embodiments, the spark plug 192 may be omitted, such as when the internal combustion engine 10 can initiate combustion by auto-ignition or by fuel injection, as may be the case with some diesel engines.

[0022] In some examples, each cylinder of the internal combustion engine 10 can be configured with one or more fuel injection devices to supply it with fuel. As a non-limiting example, cylinder 14 is shown to include two fuel injection devices 166 and 170. The fuel injection devices 166 and 170 can be configured to deliver fuel drawn from the fuel system 8. The fuel system 8 can include one or more fuel tanks, fuel pumps, and fuel distributors. According to the illustration, the fuel injection device 166 is directly coupled to cylinder 14 to inject fuel directly into it in proportion to the pulse width of the signal FPW-1, which is received by the controller 12 via an electronic driver 168.The fuel injection device 166 provides so-called direct injection (hereinafter referred to as "DI") of fuel into the combustion cylinder 14. While the injection device 166 is in . Fig. The fuel injector 166, shown positioned on one side of cylinder 14, can alternatively be located above the piston, such as near the spark plug 192. Such a position can improve mixing and combustion when the internal combustion engine is operated with an alcohol-based fuel, as some alcohol-based fuels have lower volatility. Alternatively, the injector can be located above and near the intake valve to improve mixing. Fuel can be supplied to the fuel injector 166 from a fuel tank of the fuel system 8 via a high-pressure fuel pump and fuel distributor. Furthermore, the fuel tank can include a pressure converter that provides a signal to the control unit 12.

[0023] In some examples, the direct fuel injection device 166 can be magnetically controlled, wherein the amount of fuel delivered by the injection device can be adjusted by varying a pulse width signal that is commanded to the magnet coupled to the fuel injection device. The inventors of the present invention have recognized that magnetically controlled direct injection devices can exhibit unpredictable flow characteristics in the transition region of the direct fuel injection device, between the ballistic and full-stroke regions of the injection device operation. In particular, in this region, the flow rate of the fuel injection device can be inaccurate and unpredictable, resulting in shot-to-shot and part-to-part variability.To reduce cylinder torque output imbalances and undesirable tailpipe emissions caused by the variability of the injection system, an internal combustion engine control unit can operate the direct injection system outside the transition region. As referenced in... Fig. As detailed in Section 2, an internal combustion engine control unit can determine a fuel injection profile, including a fuel mass to be delivered via the direct injection device, the number of direct injections for a given fuel injection event, and the fuel split ratio in each of those direct injections. Pulse width signals can then be determined for each of the injections. If the pulse width signal for any of the direct injections falls within the transition region of the direct injection device, the fuel injection profile can be updated. In particular, the pulse width signals for all of the direct injections can be updated to operate the direct injection device outside the transition region.For example, the fuel mass of a given direct injection can be increased or decreased, the number of direct injections can be increased or decreased, and / or the split ratio in the direct injections can be increased or decreased.

[0024] With renewed reference to Fig. In Figure 1, the fuel injection device 170 is arranged in the intake port 146 and not in the cylinder 14, a configuration which provides what is known as port fuel injection (hereinafter referred to as "PFI") into the intake port upstream of the cylinder 14. The fuel injection device 170 can inject fuel taken from the fuel system 8 proportionally to the pulse width of the FPW-2 signal received by the controller 12 via the electronic driver 171. It should be noted that a single driver 168 or 171 can be used for both fuel injection systems, or, as shown, several drivers can be used, for example, driver 168 for fuel injection device 166 and driver 171 for fuel injection device 170.

[0025] In an alternative example, each of the fuel injection devices 166 and 170 can be configured as a direct fuel injection device for injecting fuel directly into cylinder 14. In yet another example, each of the fuel injection devices 166 and 170 can be configured as an intake port fuel injection device for injecting fuel upstream of the intake valve 150. In still other examples, cylinder 14 can contain only a single fuel injection device, which is configured to receive different fuels in varying relative amounts as a fuel mixture from the fuel systems, and which is further configured to inject this fuel mixture either as a direct fuel injection device directly into the cylinder or as a port fuel injection device upstream of the intake valves.It is understood that the fuel systems described here are not to be limited by the specific designs of fuel injection devices described here as examples.

[0026] Fuel can be supplied to the cylinder by either injection device during a single cylinder cycle. For example, each injection device can provide a portion of the total fuel injection that is burned in cylinder 14. Furthermore, the distribution and / or relative amount of fuel supplied by each injection device can vary with operating conditions, such as combustion engine load, knocking, and exhaust gas temperature, as described below. Fuel injected via the intake manifold can be delivered during an open intake valve event, a closed intake valve event (e.g., essentially before the intake stroke), and during operation with both the open and closed intake valves.Similarly, directly injected fuel can be supplied, for example, during an intake stroke, partially during a preceding exhaust stroke, during the intake stroke, and partially during the compression stroke. Thus, even during a single combustion event, injected fuel can be injected from the intake manifold and direct injection systems at different times. Furthermore, multiple injections of the delivered fuel can be performed per cycle during a single combustion event. These multiple injections can occur during the compression stroke, the intake stroke, or any suitable combination thereof.

[0027] As described above, shows Fig. 1 merely one cylinder of a multi-cylinder internal combustion engine. Thus, each cylinder can likewise have its own set of intake / exhaust valves, fuel injection device(s), spark plug, etc. It is understood that the internal combustion engine 10 can include any suitable number of cylinders, including 2, 3, 4, 5, 6, 8, 10, 12 or more cylinders. Furthermore, each of these cylinders can contain some or all of the various components that are in Fig. 1 are described and illustrated with reference to cylinder 14.

[0028] Fuel injectors 166 and 170 may have different characteristics. These include differences in size; for example, one injector may have a larger injection orifice than the other. Other differences include, but are not limited to, different spray angles, different operating temperatures, different targets, different injection timings, different spray characteristics, different positions, etc. Furthermore, different effects can be achieved depending on the fuel distribution ratio between injectors 170 and 166.

[0029] Fuel tanks in fuel system 8 can contain different types of fuel, such as fuels with varying properties and compositions. These differences can include variations in alcohol content, water content, octane rating, heat of vaporization, fuel blends, and / or combinations thereof. For example, fuels with different heats of vaporization could include gasoline as the primary fuel type, with a lower heat of vaporization, and ethanol as the secondary fuel type, with a higher heat of vaporization. Alternatively, the internal combustion engine could use gasoline as the primary fuel type and an alcoholic fuel blend, such as E85 (approximately 85% ethanol and 15% gasoline) or M85 (approximately 85% methanol and 15% gasoline), as the secondary fuel type.Other possible substances include water, methanol, a mixture of alcohol and water, a mixture of water and methanol, a mixture of alcohols, etc.

[0030] In yet another example, both fuels could be alcohol mixtures with varying alcohol compositions. The first fuel could be a gasoline-alcohol mixture with a lower alcohol concentration, such as E10 (which consists of approximately 10% ethanol), while the second fuel could be a gasoline-alcohol mixture with a higher alcohol concentration, such as E85 (which consists of approximately 85% ethanol). Furthermore, the first and second fuels could also differ in other fuel properties, such as temperature, viscosity, octane rating, etc. Additionally, the fuel properties of one or both fuel tanks can change frequently, for example, due to daily fluctuations in refueling.

[0031] Control 12 is in Fig. 1 is represented as a microcomputer comprising a microprocessor unit 106, input / output ports 108, an electronic storage medium for executable programs and calibration values, in this specific example represented as non-volatile read-only memory 110 for storing executable instructions, random access memory 112, keep-alive memory 114 and a data bus.In addition to the signals discussed previously, the control unit 12 can receive various signals from sensors coupled to the internal combustion engine 10, including the measurement of mass air flow (MAF) from the mass air flow sensor 122; engine coolant temperature (ECT) from the temperature sensor 116, which is coupled to the cooling sleeve 118; a profile ignition pickup signal (PIP) from the Hall effect sensor 120 (or other type), which is coupled to the crankshaft 140; throttle position (TP) from a throttle position sensor; and absolute manifold pressure (MAP) from sensor 124. An internal combustion engine speed signal (RPM) can be generated by the control unit 12 from the PIP signal. The manifold pressure signal MAP from a manifold pressure sensor can be used to provide an indication of vacuum or pressure in the intake manifold.

[0032] The controller 12 receives signals from the various sensors. Fig. 1 and suspends the various actuators Fig. 1. To adjust the combustion engine operation based on received signals and instructions stored in the control unit's memory. For example, the control unit can adjust a fuel pulse width signal sent to the direct fuel injection device to operate the direct injection device outside of a transition region of the injection device.

[0033] In this way, the components from Fig. 1. An internal combustion engine system comprising an internal combustion engine cylinder; a direct injection device for supplying fuel to the cylinder; and a controller with computer-readable instructions stored in non-volatile memory for: estimating an initial fuel injection profile for a combustion cycle of the cylinder based on the internal combustion engine speed / load and the internal combustion engine temperature, wherein the initial fuel injection profile includes multiple direct injection fuel pulses, wherein at least one of the multiple direct injection fuel pulses has a pulse width in a transition region of the direct injection device; during a first condition, modifying the initial fuel injection profile to a first modified fuel injection profile with a smaller number of multiple direct injection fuel pulses.wherein each of the smaller number of multiple direct injection fuel pulses has a smaller pulse width in a stroke region of the direct injection device; and during a second condition, modifying the initial fuel injection profile to a second modified fuel injection profile, wherein the pulse width of a first set of the multiple direct injection fuel pulses is reduced in a ballistic region of the direct injection device, while the pulse width of a second set of the multiple direct injection fuel pulses is increased in the full-stroke region of the direct injection device, while maintaining a number of the multiple direct injection fuel pulses,where the total mass of directly injected fuel in each of the first and second modified fuel injection profiles is the same as the fuel mass in the initial fuel injection profile. In one example, during a first condition, the fuel masses can be combined if no solution can be found by adjusting the fuel mass because the ballistic injection is below the minimum pulse width of the fuel injection device. A minimum pulse width must exist in the ballistic region because, at a certain point, the small fuel pulses from shot to shot and from injection device to injection device become too imprecise, and the risk of the injection device failing to open becomes unacceptable.can increase. The multiple direct injection fuel pulses of the initial fuel injection profile can include an initial number of direct injection fuel pulses, and the modification during each of the first and second conditions is based on the initial number of direct injection fuel pulses and further on the pulse width of at least one of the multiple direct injection pulses relative to an upper pulse width limit of the ballistic region and a lower pulse width limit of the stroke region. The system can further include a port fuel injector for supplying fuel to the cylinder, the control including further instructions for: during a third second condition, modifying the initial fuel injection profile to a third modified fuel injection profile, including adjusting the total mass of directly injected fuel.to move the pulse width of at least one of the several direct injection fuel pulses from the transition region of the direct injection device, and to adapt a port-injected fuel mass based on the adapted direct-injected fuel mass.

[0034] The components from Fig. 1 further enable an internal combustion engine system comprising: an internal combustion engine cylinder; a direct injection device for supplying fuel to the cylinder; a port injection device for supplying fuel to the cylinder; and a control system with computer-readable instructions stored in non-volatile memory for: estimating an initial fuel injection profile for a combustion cycle of the cylinder based on the internal combustion engine speed / load and the internal combustion engine temperature, wherein the initial fuel injection profile has an initial split ratio of directly injected fuel to port-injected fuel delivered over several direct injection fuel pulses, wherein at least one of the several direct injection fuel pulses has a pulse width in a transition region of the direct injection device; and modifying the initial fuel injection profile.to modify the ratio of directly injected fuel to port-injected fuel such that at least one of the multiple direct injection fuel pulses is moved out of the transition region. This modification may involve increasing or decreasing a port-injected fuel mass relative to a total directly injected fuel mass, based on the pulse width of at least one of the multiple direct injection pulses relative to an upper pulse width limit of a ballistic region and a lower pulse width limit of a stroke region of the direct injection device. Decreasing the total directly injected fuel mass may involve decreasing the number of multiple direct injection fuel pulses to move the pulse width of each of the reduced number of direct injection fuel pulses into the stroke region.and where increasing the total mass of directly injected fuel involves increasing the number of multiple direct injection fuel pulses in order to move the pulse width of each of the increased number of direct injection fuel pulses into the ballistic region.

[0035] Now, the focus will shift to... Fig. Reference is made to a method 200 illustrating an exemplary method for modifying a fuel injection profile for operating a direct injection device outside its transition region. The method from Fig. 2 can be interpreted as executable instructions stored in non-volatile memory in the system. Fig. 1. Furthermore, the procedure may consist of Fig. 2 the operating sequence from the Fig. 5-11. Instructions for carrying out procedure 200 and the other procedures contained herein may be provided by a controller based on instructions stored in a memory of the controller and in conjunction with sensors of the internal combustion engine system, such as those referred to above. Fig. The control system can execute the signals received from the sensors described in section 1. The system can utilize combustion engine actuators of the combustion engine system to adjust the combustion engine operation according to the procedures described below.

[0036] In the case of 202, the procedure involves estimating and / or measuring internal combustion engine operating conditions. These may include, for example, internal combustion engine speed, internal combustion engine load, internal combustion engine temperature (such as derived from the internal combustion engine coolant temperature), exhaust gas temperature, catalyst temperature (Tcat), desired torque, boost level, dilution requirement, etc.

[0037] In 204, the procedure involves determining an initial fuel injection profile based on the estimated internal combustion engine operating conditions. In 206, determining the initial fuel injection profile involves determining an overall fuel split ratio to be delivered via direct injection (DI) relative to port fuel injection (PFI). The control unit can determine a total fuel mass to be delivered in a given combustion cycle based on the driver torque demand and the internal combustion engine speed / load, and then determine what proportion of this total fuel mass is to be delivered via the direct injection device relative to the port fuel injection device.As an example, during a cold start of an internal combustion engine, where the internal combustion engine coolant temperature, estimated before the initiation of combustion in the internal combustion engine, is below a threshold (such as below the start-up temperature of an exhaust gas catalyst), a larger proportion of the fuel mass can be delivered as port injection relative to direct injection (for at least a number of combustion events since the internal combustion engine was started from rest) in order to reduce particulate emissions and cold start combustion roughness induced by direct injection.In comparison, during an internal combustion engine operation where the coolant temperature, estimated before combustion begins, exceeds the threshold, a larger proportion of the fuel mass can be delivered via direct injection relative to port injection (for at least a certain number of combustion cycles since the engine started from rest) to take advantage of the higher power output and charge cooling effect of direct injection. It will be understood that in other examples, the entire commanded fuel mass can be delivered either via port injection or via direct injection.

[0038] In another example, the initial fuel injection profile can be based on the combustion chamber temperature. Large direct injection (DI) injections (for example, when the DI fuel mass exceeds a threshold) can strike the combustion chamber wall / piston and generate particulate emissions. Therefore, if the combustion chamber temperature is higher, the split ratio can be adjusted to reduce the proportion of DI fuel mass and increase the proportion of pre-fuel injection (PFI) fuel mass. As yet another example, maximum flow limits can be considered in the initial fuel injection profile, particularly when fuel from both injectors is required to deliver the total fuel mass needed to start the internal combustion engine while the injectors are cold. This can be especially relevant when dealing with elevated fuel ethanol content.In another example, the internal combustion engine start time can be considered when determining the initial fuel injection profile. The direct injection (DI) device can inject during the compression stroke, allowing the engine to start on an earlier cylinder, thus reducing the start time. If shorter start times are required, a larger proportion of the total fuel mass can therefore be delivered via direct injection. As yet another example, the flow rate of the high-pressure fuel pump (HPP) coupled to the direct injection devices can be considered when determining the initial fuel injection profile. If the DI injectors could allow the HPP to flow out, then a larger proportion of the total fuel quantity could be delivered as fuel injection (PFI) during an internal combustion engine start.

[0039] In one example, the amount of fuel delivered via port and direct injection devices is empirically determined and stored in a predefined lookup table or in functions. For example, one table might correspond to determining port injection quantities, and another to determining direct injection quantities. The two tables can be indexed to internal combustion engine operating conditions, such as engine speed and load, among other operating conditions. Furthermore, the tables can output a quantity of fuel to be injected via port fuel injection and / or direct injection into the internal combustion engine cylinders during each combustion cycle.

[0040] As another example, the control unit can make a logical determination (e.g., regarding a pulse width to be sent to a magnet of the intake manifold and direct fuel injection devices) based on logical rules that depend on parameters such as combustion engine speed and load, and furthermore on the combustion engine temperature. The control unit can then generate a pulse width control signal that is sent to the injection device magnets.

[0041] Determining the initial fuel injection profile, as described in section 208, further involves determining the number of injections per combustion cycle over which the fuel mass is to be delivered. For example, one or more of the port-injected fuel mass and the direct-injected fuel mass can be delivered as multiple injections over a given combustion cycle. In one example, the port-injected fuel mass can be delivered as a single port injection, while the direct-injected fuel mass can be delivered as multiple direct injections in a given combustion cycle. The number of injections for each of these multiple injections can be determined based on the combustion engine operating conditions.For example, the number of direct injections through which the directly injected fuel mass is delivered can be higher during a cold start of an internal combustion engine (per combustion cycle) compared to a hot start. During cold starts, the control unit can use both PFI and DI fuel injection. The DI fuel can be used to accelerate catalyst warm-up. However, since DI fuel can increase emissions due to particles contacting the combustion chamber, the DI fuel pulse can be split into multiple injections.

[0042] The number of injections can also be based on the fuel mass to be delivered. For example, if the fuel mass to be delivered via the direct injection system increases and exceeds the maximum pulse width of the direct injection system, the fuel mass can be divided into multiple injections, each with a pulse width at or below the maximum pulse width. Similarly, if the fuel mass to be delivered via the port injection system increases and exceeds the maximum pulse width of the port injection system, the fuel mass can be divided into multiple injections, each with a pulse width at or below the maximum pulse width. The multiple port injections can include multiple injections during the exhaust stroke (with a closed intake valve), during the intake stroke (with an open intake valve), or a combination thereof.The multiple direct injections can include multiple injections during the intake stroke, the compression stroke, or a combination thereof.

[0043] By splitting the injection into multiple injections, the amount of fuel that hits internal combustion engine components, such as the piston and cylinder walls, is reduced. When fuel hits these components, it can either run down the walls, potentially damaging the engine and allowing excess fuel to enter the oil, or it can burn and produce particulate emissions. Splitting the fuel into smaller pulses prevents this. Compression injection can also be used, ensuring that the atomized fuel is located near the spark plug when the ignition spark is generated.

[0044] Determining the initial fuel injection profile in the 210 also involves determining the fuel split ratio across multiple injections. For example, if the directly injected fuel mass is delivered as a split direct injection, comprising at least one intake stroke injection (DI_int) and at least one compression stroke injection (DI_comp) in a given combustion cycle, the control unit can determine the proportion of the directly injected fuel mass delivered via the intake stroke injection relative to the compression stroke injection. If the directly injected fuel mass is delivered via multiple intake stroke or multiple compression stroke injections in a given combustion engine cycle, the split ratio of the directly injected fuel mass in each of the injections can be determined similarly.In one example, during a cold start of an internal combustion engine, the directly injected fuel mass can be delivered as a split direct injection, with a larger proportion of the directly injected fuel mass being delivered during the compression stroke and a smaller proportion of the fuel mass being delivered during the intake stroke. In another example, during a cold start of an internal combustion engine, the directly injected fuel mass can be delivered as a split compression-stroke direct injection, with a larger proportion of the fuel being delivered earlier during a compression stroke of the combustion cycle and a remaining smaller fraction of the fuel being injected later during the compression stroke of the combustion cycle.

[0045] The injection split ratio and the number of injections within the split injection can be based on combustion engine operating conditions, such as the combustion engine temperature at start-up, ambient temperature, and the alcohol content of the injected fuel. Furthermore, the split ratio and the number of injections can also be adjusted based on the exhaust catalyst temperature, the particulate filter load, and the engine's soot production tendencies at start-up. For example, the number of compression stroke direct injections can be increased if the alcohol content of the injected fuel increases.As another example, the number of compression stroke injections applied during an initial combustion event can be increased if the engine temperature or ambient temperature drops at the time of the cold start. In one example, multiple compression stroke direct injections of an alcohol fuel can be advantageously used to warm the engine and catalyst, thereby accelerating catalyst activation and improving engine and catalyst performance under cold-start conditions, while simultaneously reducing the soot load from the direct injection.

[0046] As an example, the control unit can determine a control signal to be sent to the actuators of the direct and port fuel injection devices, such as a pulse width of the signal determined based on the engine speed and load, as well as the engine temperature, fuel alcohol content (or fuel octane rating), and engine load. The engine speed can be based on the output of a crankshaft sensor, and the engine load can be based on the operator torque demand. The control unit can determine the pulse widths to be sent to each injection device by a setting that directly considers the engine speed / load and engine temperature, such as increasing the direct injection pulse width as the engine speed and load increase.The controller can alternatively determine the pulse width based on a calculation using a lookup table, where the input is relative humidity and the output is the pulse width.

[0047] It will be understood that when determining the DI:PFI split ratio, the number of injections and the direct injection split ratio, the control system can determine a fuel pulse width signal to command each of the injections based on the fuel distributor pressure and a fuel mass to be delivered in each injection.

[0048] At 212, it can be determined whether any of the DI fuel pulses of the specified fuel injection profile lie within the transition region of the direct injection device (in particular a direct injection device operating map). As with reference to Fig. As elaborated in section 4, the transition region is positioned between the ballistic and lift (or linear) regions of the direct injection device, and the variability of the direct injection device is greater in the transition region than in either the ballistic or lift region. Determining whether any of the DI fuel pulses lie within the transition region of the direct injection device can, for example, involve determining whether the pulse width signal for any of the DI fuel pulses is less than an upper threshold corresponding to the lift region of the direct injection device and greater than a lower threshold corresponding to the ballistic region of the direct injection device, where the upper and lower thresholds are based on the fuel rail pressure. Therefore, the transition region encompasses a specific pulse width range at different fuel rail pressures.When the pressure in the DI injector changes, the characteristics of the injector change. Thus, the transition region shifts and changes its size at different fuel rail pressures. Consequently, it must be calibrated for each injector design (e.g., part number), but not for each injector individually. A set of limit sample injectors can be used to calibrate the pulse width ranges at each pressure, and then the calibration can be used to cover the entire population of injectors. If none of the DI fuel pulses are in the transition region, the process proceeds to 214 to deliver fuel according to the specified fuel injection profile, and the process ends.

[0049] With brief reference to Fig. Figure 400 is an example of the operating regions of a direct injection device. Figure 400 represents the injection device pulse width along the x-axis and the fuel mass along the y-axis. The relationship between a commanded direct injection device pulse width and an actual delivered fuel mass is shown in Figure 402.

[0050] Figure 402 shows the direct injection device in its different regions (ballistic, transition, full stroke) as the electrical pulse width applied to the injection device increases. Initially, the injection device doesn't even open; a minimal electrical pulse is required for it to open and for fuel to begin flowing. The ballistic region is the period when the needle is not fully open. In this region, small changes in electrical pulse width will result in large changes in fuel mass (due to the very steep rise in this region). In the transition region, the needle can flex, and the fuel delivery can be very unpredictable (from shot to shot and from injection device to injection device). The full-stroke region always exhibits the same less steep rise and is linear.For example, if 100 ml flow with a pulse width of 1 ms, then 200 ml flow in the linear region with a pulse width of 2 ms.

[0051] At a higher commanded fuel pulse width, the injection device operates in the stroke region 406, with a linear change in fuel mass with the commanded pulse width. At a very small commanded fuel pulse width, the injection device operates in the ballistic region 404, where some variability may be present. In particular, at very low commanded pulse widths below the minimum pulse width of the injection device, no fuel is delivered. However, there is still a linear change in fuel mass with the commanded pulse width. In the region between the stroke and ballistic regions, especially in the mid-transition region 408, the injection device operates with very high variability.Based on the position of the pulse width within the transition region, the actual fuel mass delivered may be, for example, larger or smaller than planned. Furthermore, the variability is non-linear and difficult to predict or model, making it difficult to compensate for.

[0052] In particular, increasing the electrical pulse width for the fuel injection device in the ballistic region increases the amount of mass delivered at a higher rate (steeper rise). Although some variability may exist in the rise, this variability can be mapped, and the shape or shift of the rise in the ballistic region can be adjusted to accommodate it. For example, the rise can be made steeper or less steep based on the variability. However, in the transition region, an increased pulse width can actually lead to a decrease in the injected fuel mass.Because the shape and rise in the transition region vary drastically, both from shot to shot and from injector to injector across the population of injectors, it may be impossible to simply shift and reshape the transition region rise. This variability is exacerbated by the fact that the transition region rise differs for each injector and varies significantly from shot to shot.

[0053] As elaborated here, updating a fuel injection profile to move a DI fuel pulse out of the transition region can reduce fuel delivery errors and resulting torque errors and emissions problems. Therefore, avoiding the injection device's transition region is not as simple as changing the pulse width of an injection to jump from the end of the ballistic region to the beginning of the full-stroke region, because the fuel mass delivered in region 404 is significantly lower than the fuel mass delivered in region 406. This would cause a sharp jump in the fuel delivered to the combustion engine. Therefore, updating the injection device's pulse width alone may not be sufficient to avoid the transition region.Instead, the fuel mass of each of the injection pulses of the initial fuel injection profile may need to be modified to maintain the total fuel mass delivered to the internal combustion engine, as in relation to . Fig. 3 and the examples from the Fig. 5-11 elaborated.

[0054] With renewed reference to Fig. 2. The procedure then includes, if any of the DI fuel pulses of the initially determined fuel injection profile lies within the transition region, updating the fuel injection profile at 216 to move the affected DI fuel pulse(s) out of the transition region. Updating the fuel injection profile at 218 includes updating the DI:PFI split ratio. For example, the proportion of the total fuel mass delivered via direct injection can be increased, while the proportion delivered via port fuel injection is correspondingly decreased. As another example, the proportion of the total fuel mass delivered via direct injection can be decreased, while the proportion delivered via port fuel injection is correspondingly increased.The control unit can estimate an initial ratio of port-injected fuel to direct-injected fuel in a combustion cycle based on the internal combustion engine operating conditions, such as during a cold start. If the initial ratio places direct fuel injection in a transition region of the direct injection device map, the control unit can update the initial ratio to move the direct fuel injection out of the transition region. This update can be based on the pulse width of the direct fuel injection relative to either a ballistic-to-transition boundary or a stroke-to-transition boundary of the direct injection device map.As an example, in response to the fact that the distance of the direct fuel injection pulse width from the ballistic-to-transition boundary of the direct injection device map is smaller than the distance of the direct fuel injection pulse width from the stroke-to-transition boundary of the direct injection device map, the control system can decrease a directly injected fuel mass to move the pulse width from the transition region into the ballistic region of the direct injection device map, while increasing a port-injected fuel mass.As another example, in response to the fact that the distance of the direct fuel injection pulse width from the ballistic-to-transition boundary of the direct injection device map is greater than the distance of the direct fuel injection pulse width from the lift-to-transition boundary of the direct injection device map, the control system can increase the directly injected fuel mass to move the pulse width from the transition region to the lift region of the direct injection device map, while simultaneously decreasing the port-injected fuel mass. The initial ratio of port-injected to directly injected fuel can involve multiple direct injections in the combustion cycle, and the increase and decrease can be based on the number of these multiple direct injections.

[0055] As detailed below, the control system can adjust the number of multiple direct injections by decreasing the number of injections to move the pulse width from the transition region to the lift region. Here, the decrease can occur in response to the unadjusted number of injections exceeding a threshold. As another example, the control system can adjust the number of injections by increasing the number of injections to move the pulse width from the transition region to the ballistic region. Here, the increase can occur in response to the unadjusted number of injections falling below a threshold.In one example, the multiple direct injections can include multiple direct injections in an intake stroke and / or a compression stroke of the combustion cycle, and the update can further include updating a split ratio of the directly injected fuel delivered in the intake stroke relative to the compression stroke.

[0056] Updating the fuel injection profile at 220 can additionally or optionally include updating the number of injections over which the fuel mass is delivered. For example, the total number of direct injections can be increased by splitting some fuel pulses into several smaller fuel pulses. Conversely, the total number of direct injections can be decreased by combining some fuel pulses into fewer, larger fuel pulses. Updating the fuel injection profile at 222 can additionally or optionally include updating the direct injection split ratio of the fuel delivered in the multiple direct injection pulses.For example, the amount of total directly injected fuel delivered via compression stroke direct injection can be increased, while the amount of fuel delivered via intake stroke direct injection is decreased. Alternatively, the amount of total directly injected fuel delivered via compression stroke direct injection can be decreased, while the amount of fuel delivered via intake stroke direct injection is increased. Further options are possible, as described in the procedure outlined in [reference to relevant document]. Fig. 3 and the examples from the Fig. Described in sections 5-11, the update can be performed based on the position of the fuel mass of the DI fuel pulse in the transition region relative to each of the stroke and ballistic regions. In this way, DI fuel pulses can be modified to operate the direct injection device outside the transition region, thereby reducing fuel delivery errors and related problems.

[0057] In one example, the control unit can update the fuel injection profile during a first condition by adjusting the fuel mass between DI injections, while maintaining the number of DI injections, as it deviates as little as possible from the base combustion engine calibration. In another example, since reducing the number of DI injections could decrease the effectiveness of multiple injections in terms of reducing particulate matter emissions, the number of DI injections can be reduced during a second condition if the exhaust gas fouling is below a threshold. In yet another example, the DI / PFI split ratio can be modified during a third condition; however, limits can be applied to adjusting the split ratio before it can begin to affect limit ignition timing and charge air cooling (performance).

[0058] In other examples, a combination of the aforementioned approaches may be selected. The selection can be based on internal combustion engine operating conditions, such as engine speed and NVH (noise, vibration, and harshness) limitations. For example, engine speed limitations may restrict the total number of injections the powertrain control module is capable of. At higher engine speeds, the engine control unit may not be able to manage the power loss from multiple fuel injections. Therefore, updating the injection profile at higher engine speeds may involve reducing the number of injections or, if increasing the number of injections, increasing them by a smaller amount (i.e., limiting the increased number of injections).As another example, additional fuel injections can increase ticking noises, which can negatively affect customer perception. Therefore, if ticking noises are already present, updating the injection profile may involve reducing the number of injections or, if increasing the number of injections, increasing it by a smaller amount (i.e., limiting the increased number of injections).

[0059] At 224, fuel is delivered according to the updated fuel injection profile. For example, the control unit can determine the required fuel pulse widths based on the updated fuel masses of the various pulses and then send these signals to the appropriate fuel injectors. The process then ends.

[0060] Now, the focus will shift to... Fig. Reference is made to Figure 300, which shows an exemplary method for updating a fuel injection profile in order to move a DI fuel pulse out of a transition region of the direct injection device. The method from Fig. 3 can be part of the procedure Fig. 2, as for example in 216, are carried out.

[0061] In 302, the method involves determining whether any DI fuel pulse of an initially determined fuel injection profile lies within the transition region of a direct injection device map. If not, the method proceeds to 322 to deliver fuel according to the unmodified fuel injection profile. This involves sending pulse width signals to the fuel injection devices according to the initial fuel injection profile.

[0062] If one or more of the direct injection (DI) fuel pulses of the initial fuel injection profile are determined to have a fuel pulse within the transition region, the procedure proceeds to 304, determining the position of the affected DI fuel pulse(s) within the transition region of the injection device. For example, a distance of the affected DI fuel pulse(s) from each of the ballistic region (in particular, from a boundary between the transition region and the ballistic region) and the lift region (in particular, from a boundary between the transition region and the lift region) can be estimated. The control can refer to a direct injection device map, such as the exemplary map from Fig. 4, refer to estimate the distance.

[0063] At 305, it can be determined whether the fuel pulse in the transition region is closer to the ballistic region relative to the lift region. For example, a first distance of the fuel pulse from the ballistic-to-transition boundary can be compared with a second distance from a lift-to-transition boundary. If the first distance is smaller than the second distance, the fuel pulse in question is determined to be closer to the ballistic region. It will be understood that each of the DI fuel pulses in the transition region can be assessed in a similar manner.

[0064] If the affected DI fuel pulse is closer to the ballistic region of the injection device, then the procedure at 310 involves decreasing the pulse width commanded for the affected DI fuel pulse in order to move it from the transition region to the ballistic region. As a result of the change in pulse width, the mass of fuel delivered in the affected fuel is reduced. If, in comparison, the affected DI fuel pulse is closer to the lift region of the injection device, such as when the second distance is less than the first distance, then the procedure at 308 involves increasing the pulse width commanded for the affected DI fuel pulse in order to move it from the transition region to the lift region. As a result of the change in pulse width, the mass of fuel delivered in the affected fuel is increased.

[0065] In response to the fact that the distance of the DI fuel pulse (e.g., fuel mass or fuel pulse width of the affected DI fuel pulse) from the ballistic-to-transition boundary of the direct injection device map is smaller than the distance of the affected fuel pulse from the stroke-to-transition boundary of the direct injection device map, the control system can thus decrease the fuel mass of one of the multiple direct injections to move the fuel mass from the transition region to the ballistic region of the direct injection device map, while increasing the fuel mass of another of the multiple direct injections.In an alternative example, in response to the fact that the distance of the fuel mass from the ballistic-to-transition boundary of the direct injection device map is greater than the distance of the fuel mass from a stroke-to-transition boundary of the direct injection device map, the control system can increase the fuel mass of one of the multiple direct injections to move the fuel mass from the transition region into the stroke region of the direct injection device map, while decreasing the fuel mass of another of the multiple direct injections. Here, the increase and decrease can be based on a total number of the multiple direct injections in the initial (unmodified) DI fuel injection profile, as well as a proportion of these injections that lie in the transition region.

[0066] From each of 308 and 310, the procedure proceeds to 320, where the procedure involves adjusting a pulse width commanded to each of the remaining DI fuel pulses (those outside the transition region) and PFI fuel pulses to maintain the total fuel mass. In other words, the total fuel mass delivered via the unmodified fuel injection profile and the modified fuel injection profile remains constant. In yet other examples, adjusting the pulse width may involve adjusting the directly injected fuel mass to move the affected pulse out of the transition region and then adjusting the amount of fuel delivered to the cylinder in the combustion cycle via port fuel injection, based on the updated DI fuel mass, to maintain a total fuel mass.

[0067] Additionally or optionally, the procedure can transition to 314 (from 302) during the adjustment of the affected fuel pulses based on their position within the transition region to adjust the number of direct injections. Specifically, at 314, it can be determined whether the DI fuel pulse in the transition region is part of a split direct injection. A split direct injection can be confirmed if the DI fuel mass is delivered over multiple intake and / or compression stroke direct injections. As an example, a split direct injection can involve 2-4 direct injections, which can be any combination of intake and compression stroke direct injections.

[0068] If the affected DI fuel pulse is not part of a split direct injection, such as when the DI fuel pulse is a single direct injection of the unmodified fuel injection profile, the method described in 318 involves adjusting the fuel pulse width to split the affected DI fuel pulse into several smaller DI pulses, each of which lies within the ballistic region of the injection device. Increasing the number of fuel pulses moves the affected fuel pulse out of the transition region, and each of the smaller fuel pulses is positioned within the less variable ballistic region.

[0069] If the affected DI fuel pulse is part of a split direct injection, such as when the DI fuel pulse is one of several direct injections of the unmodified fuel injection profile, the method described in 316 involves adjusting the fuel pulse to combine the affected DI fuel pulse with at least one other DI fuel pulse (such as another DI fuel pulse in the transition region, a DI fuel pulse in the ballistic region, or a DI fuel pulse in the lift region) to form a larger DI pulse in the lift region of the injection device. Increasing the number of DI fuel pulses moves the affected fuel pulse out of the transition region, and the resulting larger fuel pulse is positioned within the more linear lift region.

[0070] An example of adjusting the number of injections for operation outside the transition region of a direct injection device is given with reference to Fig. 5 shown. Card 500 represents a direct injection device card, such as card 400 from Fig. 4, which includes a ballistic region 404, a lift region 406, and a transition region 408. In this example, the initial (unmodified) fuel injection profile includes multiple direct injections per combustion cycle. Map 500 represents two DI fuel pulses 502 a, b (both having the same fuel mass and therefore the same pulse width) located in the transition region 408 of the injection device map. In alternative examples, the DI fuel pulses 502 a, b may be located in the transition region and have different fuel masses. To avoid operation in the transition region 408, the number of fuel pulses is reduced by combining the fuel pulses 502 a, b into a single fuel pulse 504 with a larger fuel mass and therefore a larger pulse width. In particular, the modified pulse width of the fuel pulse 504 lies in the lift region 406.In this way, the direct injection device operation is shifted from the transition region to the stroke region by reducing the number of direct fuel injections per combustion cycle, while maintaining the direct injection fuel mass.

[0071] Another example of adjusting the number of injections for operation outside the transition region of a direct injection device is given with reference to Fig. 5 shown. Card 600 represents a direct injection device card, such as card 400 from Fig. 4, which includes a ballistic region 404, a lift region 406, and a transition region 408. In this example, the initial (unmodified) fuel injection profile includes a single direct injection per combustion cycle.

[0072] Map 600 represents a single DI fuel pulse 602 located in the transition region 408 of the injection device map. To avoid operation in the transition region 408, the number of fuel pulses is increased by splitting the fuel pulse 602 into two fuel pulses 604a, b, each with a smaller fuel mass and therefore a smaller pulse width. In the example shown, both fuel pulses 604a, b have the same fuel mass (and therefore the same pulse width) and are located in the ballistic region 404 of the injection device map. In alternative examples, the DI fuel pulses 604a, b can be located in the ballistic region and have different fuel masses.In this way, the direct injection device operation is shifted from the transition region and into the ballistic region by increasing the number of direct fuel injections per combustion cycle, while maintaining the direct injection fuel mass.

[0073] In this way, during a first condition, the control system can reduce the number of multiple injections by combining one of the multiple direct injections with at least one other of the multiple direct injections to move the fuel mass from the transition region to the lift region. Then, during a second condition, the control system can increase the number of multiple injections by splitting one of the multiple direct injections into a multitude of direct injections in the ballistic region. In one example, during the first condition, an unmatched number of multiple injections exceeds a threshold number, while in the second condition, the unmatched number of multiple injections falls below the threshold number.

[0074] An example of adjusting the fuel mass in a multi-direct-injection fuel injection profile for operation outside the transition region of a direct-injection device is given with reference to Fig. Figure 7 shows that card 700 represents a direct injection device card, such as card 400 from [reference missing]. Fig. 4, which includes a ballistic region 404, a lift region 406, and a transition region 408. In this example, the initial (unmodified) fuel injection profile includes multiple direct injections per combustion cycle. Map 700 represents two DI fuel pulses 702a and 702b (both having the same fuel mass and therefore the same pulse width) located in the transition region 408 of the injection device map. In alternative examples, the DI fuel pulses 702a and 702b may be located in the transition region and have different fuel masses. To avoid operation in the transition region 408, the fuel mass in each of the pulses 702a and 702b is adjusted while maintaining the total directly injected fuel mass and the total number of direct injections.Specifically, the fuel mass of pulse 702a is increased to provide the modified fuel pulse 704 in the stroke region 406 of the injection device. Simultaneously, the fuel mass of pulse 702b is decreased to provide the modified fuel pulse 706 in the ballistic region 404 of the injection device. In this way, by modifying the fuel mass and pulse width for each of the multiple direct fuel injections per combustion cycle, the direct injection device operation is shifted out of the transition region.

[0075] In one example, an internal combustion engine control unit can modify each of the direct injection (DI) fuel pulses in the transition region based on each pulse's proximity to the boundary between the full-stroke and transition regions, as well as the boundary between the ballistic and transition regions. This modification can further be based on the total fuel mass to be delivered via direct injection, the total fuel mass of the affected pulse(s) in the transition region, the total number of direct injections, and the number of affected injections in the transition region. As an example, the control unit can use an algorithm such as the one described in Fig. Algorithm 800, shown in Figure 8 and elaborated below, to modify the fuel mass of each fuel pulse.

[0076] The control process begins with a desired total fuel mass to be injected (via direct injection), in Fig. 8 is determined as KMw x Nw, where KMw is the desired fuel mass to be injected per injection, and Nw is the desired number of injections. The controller then transposes the desired total fuel mass (KMw x Nw) into the same number of direct injection fuel pulses, distributed between injections in the ballistic and lift regions. Assuming that KMbe represents the fuel mass of the "ballistic end," KMls represents the fuel mass of the "linear start" (fuel mass in the lift region), and KMth represents a calibratable hysteresis for the transition region, the following equations should hold true: Ngew=Nb+Nl; KMgew×Ngew=KMlinear×Nl+KMballistisch×Nb; where KMlinear and KMballistic are the modified fuel masses for the injections planned in the stroke region (also referred to here as the linear region) and the ballistic region, and Nl and Nb respectively are the number of pulses in each region.

[0077] The following conditions must be met: KMlinear≥KMl; KMballistic≤KMb;

[0078] This can be expressed as follows: 0=Delta(KMlinear)×Nl+Delta(KMballistic)×Nb.

[0079] Further calculations and assuming that either KMlinear = KMI and / or KMballistic = KMb result in an equation for the floating point as follows: Nb−glide=(F32)Ngew×(KMΔ / SME transition).

[0080] The optimal number for ballistic and linear injections would be as follows: Nb=(U8)uclip(1UL,(U32)(Nb−glide+0.5F),((U32)Ngew−1UL)); and: Nl=Ngew−Nb;

[0081] The following equation will help in calculating KMlinear and KMballistic as follows: if (Nb != (U8)Nb-glide) { KMballistic = KMb; KMlinear = ((Ngew x KMgew) - (Nb x KMb)) / N1;} else { KMlinear = KM1; KMballistic = ((Ngew x KMgew) - (N1 x KM1)) / Nb;

[0082] In this way, a fuel mass delivered in each DI fuel pulse can be modified to operate the direct injection device outside the transition region, while maintaining the total fuel mass and total number of direct injections.

[0083] In one example, the multiple direct injections of the unmodified fuel injection profile can include multiple direct injections in an intake stroke and / or a compression stroke of the combustion cycle. Here, updating the fuel mass can involve updating the fuel split ratio of the directly injected fuel delivered in the intake stroke relative to the compression stroke. Furthermore, the number of intake stroke and compression stroke injections can be varied.

[0084] An example of adjusting the fuel split ratio delivered via direct injection relative to port injection for operation outside the transition region of a direct injection device is given with reference to Fig. Figure 9 shows an unmodified direct injection device card 900 and a modified direct injection device card 910. Cards 900 and 910 are similar to card 400 from Fig. 4, include a ballistic region 404, hub region 406 and transition region 408.

[0085] In this example, the initial (unmodified) fuel injection profile includes an initial split ratio of 50% DI:50% PFI with multiple direct injections per combustion cycle. Map 900 represents two DI fuel pulses 902 (both having the same fuel mass and therefore the same pulse width) located in transition region 408 of the injection device map, together representing the 50% DI of the initial fuel injection profile. In alternative examples, the DI fuel pulses 902 may be located in the transition region and have different fuel masses. The DI fuel pulses 902 are located in transition region 408 near a boundary of the transition region with stroke region 406. To avoid operation in transition region 408, the DI:PFI fuel split ratio is adjusted by changing the DI percentage.Since the DI fuel pulses are closer to the lift region 406 (compared to the ballistic region 404), the percentage of total fuel delivered via DI is increased from 50% to 70% to move the DI fuel pulses out of the transition region, as indicated by the modified pulses 904 in the lift region. Simultaneously, the total fuel mass is maintained by reducing the PFI percentage from 50% to 30%. In this way, the direct injection operation is shifted out of the transition region by increasing the percentage of fuel delivered via direct injection relative to port injection.

[0086] Another example of adjusting the fuel split ratio delivered via direct injection relative to port injection for operation outside the transition region of a direct injection device is given with reference to Fig. Figure 10 shows an unmodified direct injection device card 1000 and a modified direct injection device card 1010. Cards 1000 and 1010 are similar to card 400 from Fig. 4, include a ballistic region 404, hub region 406 and transition region 408.

[0087] In this example, the initial (unmodified) fuel injection profile includes an initial split ratio of 50% DI:50% PFI with multiple direct injections per combustion cycle. Map 1000 represents two DI fuel pulses 1002 (both having the same fuel mass and therefore the same pulse width) located in transition region 408 of the injection device map, together representing the 50% DI of the initial fuel injection profile. In alternative examples, the DI fuel pulses 1002 may be located in the transition region and have different fuel masses. The DI fuel pulses 1002 are located in transition region 408 near a boundary of the transition region with ballistic region 404. To avoid operating in transition region 408, the DI:PFI fuel split ratio is adjusted by changing the DI percentage.Since the DI fuel pulses are closer to the ballistic region 404 (compared to the lift region 406), the percentage of total fuel delivered via DI is specifically reduced from 50% to 30% to move the DI fuel pulses out of the transition region, as indicated by the modified pulses 1004 in the ballistic region. Simultaneously, the total fuel mass is maintained by increasing the PFI percentage from 50% to 70%. In this way, the direct injection operation is shifted out of the transition region by decreasing the percentage of fuel delivered via direct injection relative to port injection.

[0088] It will be understood that, although the examples from the Fig. Figures 5-10 illustrate the adjustment of a number of injections, a DI:PFI split ratio, and a fuel mass from multiple direct injections; this should not be considered restrictive. In other examples, various combinations of the approaches described above can be used. For example, the number of direct injections and the DI:PFI split ratio can be modified under selected conditions. As another example, each of the number of injections, the DI:PFI split ratio, and the fuel mass of multiple direct injections can be modified.

[0089] For example, during a first condition, the control system can switch to operating with multiple direct injection fuel pulses in the combustion cycle in response to the pulse width signal of a single direct injection fuel pulse within a combustion cycle being within a transition region of the direct injection device, with the pulse width signal for each of the multiple direct injection fuel pulses being outside the transition region. In contrast, during a second condition, the control system can switch to operating with a single direct injection fuel pulse in the combustion cycle in response to the pulse width signal of one of the multiple direct injection fuel pulses being within the transition region of the direct injection device, with the pulse width signal for that single direct injection fuel pulse being outside the transition region.In one example, during the first condition, the pulse width signal of each of the multiple direct injection fuel pulses lies in a ballistic region of the direct injection device, while in the second condition, the pulse width signal of the individual direct injection fuel pulse lies in a stroke region of the direct injection device. In another example, a total fuel mass delivered via direct injection in the combustion cycle is maintained during each of the first and second conditions.Furthermore, during a third condition, in response to the pulse width signal of one of the multiple direct injection fuel pulses of the combustion cycle being within the transition region of the direct injection device, the control system can adjust the pulse width signal of each of the multiple direct injection fuel pulses to move out of the transition region while maintaining a number of pulses of the multiple direct injection fuel pulses.

[0090] As an example, the first condition, during which the number of injections is increased, involves internal combustion engine operation at a lower internal combustion engine speed and / or a lower FS load; the second condition, during which the number of injections is reduced, involves internal combustion engine operation at a higher speed, a higher FS load and / or that at least one of the multiple injections in the ballistic region is too small (e.g., smaller than one or at a minimum pulse width of the injection device); and the third condition involves that an FS load is above a threshold and / or internal combustion engine NVH is above a threshold.The switching and adjusting during each of the first, second and third conditions may, for example, involve adjusting a total fuel mass delivered via direct injection in the combustion cycle, the method further comprising adjusting a fuel mass delivered via port injection in the combustion cycle based on the adjusted total fuel mass delivered via direct injection.

[0091] In yet another example, during a first condition, the control system can modify an initial fuel injection profile to a first modified fuel injection profile with a smaller number of multiple direct injection fuel pulses, where each of the smaller number of multiple direct injection fuel pulses has a smaller pulse width in a stroke region of the direct injection device, while during a second condition, the control system can modify the initial fuel injection profile to a second modified fuel injection profile, where the pulse width of a first set of multiple direct injection fuel pulses is reduced in a ballistic region of the direct injection device, while the pulse width of a second set of multiple direct injection fuel pulses is increased in the stroke region of the direct injection device.while maintaining a number of the multiple direct injection fuel pulses. Here, the total mass of directly injected fuel in each of the first and second modified fuel injection profiles can be the same as the fuel mass in the initial, unmodified fuel injection profile. As an example, the first condition might include one or more of a higher internal combustion engine speed and a higher fuel injection load, while the second condition might include one or more of a lower internal combustion engine speed, higher internal combustion engine NVH, and that...that at least one of the injections of the initial fuel injection profile operates at or around the minimum pulse width(s) of the injection device. The multiple direct injection fuel pulses of the initial fuel injection profile can include an initial number of direct injection fuel pulses, and the modification during each of the first and second conditions can be based on the initial number of direct injection fuel pulses and further on the pulse width of at least one of the multiple direct injection pulses relative to an upper pulse width limit of the ballistic region and a lower pulse width limit of the stroke region. In addition, during a third second condition, the control can modify the initial fuel injection profile to a third modified fuel injection profile, including adjusting the total mass of directly injected fuel.to move the pulse width of at least one of the several direct injection fuel pulses from the transition region of the direct injection device, and to adapt a port-injected fuel mass based on the adapted direct-injected fuel mass.

[0092] In yet another example, during a first condition, the control system can reduce the number of direct injection fuel pulses while maintaining a direct injection to port injection ratio in response to the pulse width of one of the multiple direct injection fuel pulses of a combustion cycle lying within a transition region of a direct injection device map. During a second condition, the control system can adjust the direct injection to port injection ratio in response to the pulse width of one of the multiple direct injection fuel pulses of the combustion cycle lying within the transition region of the direct injection device.As an example, adjusting the split ratio can involve increasing the ratio of direct-injected fuel to port-injected fuel over the combustion cycle if more fuel mass is needed in the ballistic DI injection because it is smaller than the minimum permissible pulse width of that injection device. Instead of splitting the DI pulses into the ballistic and linear regions, in another representation, the pulse is split into two ballistic injections, and the remaining mass is then fed into the PFI system, thereby changing both the number of DI injections and decreasing the direct-injected fuel to port-injected fuel split ratio over the combustion cycle.Adjusting the split ratio can also involve maintaining the number of multiple direct injection fuel pulses in the combustion cycle. Alternatively, adjusting the split ratio can involve adjusting the number of multiple direct injection fuel pulses in the combustion cycle, as well as the fuel mass delivered in each of the multiple direct injection fuel pulses. In an example, during the first condition, the pulse width of each of the reduced number of multiple direct injection fuel pulses lies within a full-stroke region of the direct injection device. The number of pulses at DI can be maintained by adding more fuel to avoid the minimum pulse width or by removing fuel so that all DI injectors can be in the ballistic region.In another approach, the number of DI pulses could be reduced, and the additional mass could be fed into the PFI system. In yet another approach, the number of DI pulses could be increased by taking fuel from the PFI system and feeding it into the DI system, thereby increasing both the number of DI injections and the ratio of directly injected to port-injected fuel over the combustion cycle.

[0093] Exemplary modified fuel injection profiles, to which several different adjustments can be applied in order to move a direct injection fuel pulse out of the transition region, are described with reference to Fig. 11 shown. The map 1100 from Fig.Figure 11 shows exemplary fuel injection profiles 1102-1104 that can be used during internal combustion engine operation in response to an initial fuel injection profile 1101 with a direct injection (DI) fuel pulse located within the transition region of an operating map of a direct injection device. Each injection profile represents a point in time of injection relative to a cylinder piston position or a cylinder stroke. Based on the position of the cylinder piston at any given time in the internal combustion engine cycle, fuel can be injected during an intake stroke (I), a compression stroke (C), a power stroke (P), or an exhaust stroke (E). The injection profile further indicates whether fuel was injected via intake manifold injection (hatched blocks), single or multiple direct injections (striped blocks), or both.

[0094] An initial fuel injection profile can be determined based on the internal combustion engine operating conditions, including engine speed, driver torque demand, engine temperature, and fuel alcohol content. For example, the initial fuel injection profile could be a cold-start fuel injection profile. In a given combustion cycle, the initial fuel injection profile involves injecting a portion of the fuel as a port injection (hatched block) during a closed intake valve event (that is, during an exhaust stroke of a previous cylinder combustion event), while the remaining portion of the fuel is injected as an intake stroke direct injection and two compression stroke direct injections (diagonally striped blocks).The injection quantities can be adjusted such that 35% of the fuel injection can be delivered as a port injection during an event with the intake valve closed (e.g., during an exhaust stroke), another 35% of the fuel injection can be delivered as an intake stroke direct injection, while the remaining 30% of the fuel injection is delivered as the multiple compression stroke direct injections. Here, the fuel mass in the second (latest in the combustion cycle) compression stroke injection can correspond to a pulse width that lies in the transition region of the direct injection device.

[0095] To avoid the transition region, the initial fuel injection profile can be updated to a first modified fuel injection profile (updated fuel injection profile_A), increasing the number of compression-stroke direct injections by splitting the first (earlier in the combustion cycle) compression-stroke DI pulse into two smaller compression-stroke DI pulses. Additionally, the amount of fuel delivered via DI during the compression stroke is reduced, while the amount delivered via DI during the intake stroke is correspondingly increased. No changes are made to the proportion of fuel delivered via port fuel injection, thus maintaining the overall DI:PFI ratio.Thus, in this example, the compression-stroke direct injection (DI) fuel pulse, which was predicted to be in the transition region, is moved into the ballistic region by increasing the number of direct injections and by changing the ratio of the fuel mass delivered in each direct injection. In one example, the first modified fuel injection profile can be selected in response to the injection mode. If the internal combustion engine is in a mode requiring catalyst heating, then the DI compression injection size and injection timing are of great importance. Other fuel delivery parameters, such as the DI intake fuel mass, can be adjusted without affecting emissions, in the same way as the DI compression injection was changed.

[0096] To avoid the transition region, the initial fuel injection profile can be updated to a second modified fuel injection profile (updated fuel injection profile_B). This reduces the number of compression-stroke direct injections by combining the first and second compression-stroke DI pulses into a single compression-stroke DI pulse, while also reducing the total amount of fuel delivered during the compression stroke. The amount of DI fuel delivered during the intake stroke is increased slightly until the maximum pulse width of the direct injection system is reached. Adjusting the remaining fuel mass is achieved by increasing the proportion of fuel delivered via port fuel injection, thereby reducing the overall DI:PFI ratio.Thus, in this example, the compression-stroke DI fuel pulse, which was predicted to be in the transition region, is moved into the ballistic region by decreasing the number of direct injections, changing the ratio of fuel mass delivered in each direct injection, and decreasing the DI:PFI fuel ratio. In one example, the second modified fuel injection profile can be selected in response to maintaining the same fuel-to-air control. If fuel mass needs to be moved out of the DI injections to ensure that the DI pulses are not in the transition region, then the PFI can be increased in response.

[0097] To avoid the transition region, the initial fuel injection profile can be updated to a third modified fuel injection profile (updated fuel injection profile_C). This reduces the number of compression-stroke direct injections by combining the first and second compression-stroke DI pulses with an intake-stroke DI fuel pulse to provide a single intake-stroke DI pulse, while simultaneously increasing the total amount of fuel delivered via direct injection. The proportion of fuel delivered via port fuel injection is correspondingly reduced, thereby increasing the overall DI:PFI ratio.Thus, in this example, the compression stroke DI fuel pulse, which was predicted to be in the transition region, is moved into the ballistic region by decreasing the number of direct injections, changing the ratio of fuel mass delivered in each direct injection, and increasing the DI:PFI fuel ratio. In one example, the third modified fuel injection profile can be selected in response to maintaining the same fuel-to-air control and driver-demand torque at higher loads where charge cooling is required.

[0098] In another example, at higher engine loads, such as when more power, increased charge air cooling, or advanced ignition timing is required, the control system can increase the ratio of directly injected to port-injected fuel over the combustion cycle. Conversely, at lower engine loads, such as when fuel system load or exhaust emissions exceed a threshold, the control system can decrease the ratio of directly injected to port-injected fuel over the combustion cycle.

[0099] In other examples, the control unit may continue adjusting the fuel mass until no solution can be found that places the pulses in the full-stroke and ballistic region. At this point, the number of injection units can be reduced by one, and a solution is determined. The control unit can repeatedly adjust the number of pulses and then the number of injection units until the profile is reduced to one injection. If this injection is still in the transition region, the DI / PFI split ratio can be changed (e.g., increased or decreased) to move the DI injection out of the transition region.

[0100] In yet another example, the control unit can combine fuel pulses if no option exists to maintain the number of injections while redistributing them between the ballistic and full-stroke regions. Therefore, the control unit can prioritize maintaining the number of pulses and redistributing the fuel mass between the full-stroke and transition regions. If a solution is not possible because the injection in the ballistic region is below the minimum pulse width of the injector, then the number of pulses can be reduced to allow full-stroke injections.

[0101] Furthermore, if more directly injected fuel mass is required to allow the control unit to split the transition region injections into ballistic and full-stroke region injections, the control unit can increase the ratio of directly injected to port-injected fuel over the combustion cycle. Conversely, if less directly injected fuel mass is required to move an injection out of the transition region (for example, because the number of direct injection devices has been reduced), the control unit can decrease the ratio of directly injected to port-injected fuel over the combustion cycle.

[0102] This reduces the variability of a direct injection system, thereby enabling the reduction of gas and particulate emissions. For example, gas and particulate emissions can be reduced without reducing the number of injections in a dual-fuel engine (PFDI). The technical effect of adjusting the number, fuel mass, and split ratio of one or more direct injection fuel pulses based on the pulse's position relative to a transition region of the direct injection system is that direct injection can be provided outside the highly variable transition region while maintaining a total fuel mass to be delivered in a given combustion cycle.Furthermore, the extent of calibration efforts required by the internal combustion engine can be reduced relative to the efforts that would have been necessary to map the fuel mass distribution between fuel pulses in a forward-coupled manner. As a result of operating outside the inaccurate transition region of the direct injection device, internal combustion engine air-fuel ratio and torque errors can be reduced, improving drivability.

[0103] An exemplary procedure for an internal combustion engine comprises: delivering fuel to a cylinder in a combustion cycle as multiple direct injections; and, in response to a fuel mass from one of the multiple direct injections being located in a transition region of a direct injection device map, updating one or more of the ratios of fuel delivered in each of the multiple direct injections and the number of multiple injections to move the fuel mass of one of the multiple direct injections out of the transition region. In the preceding example, the transition region is additionally or optionally positioned between a ballistic region and a stroke region of the direct injection device map, and the direct injection device variability in the transition region is higher than in either the ballistic region or the stroke region.In one or all of the preceding examples, the update is additionally or optionally based on the position of the fuel mass relative to each of a ballistic-to-transition boundary and a lift-to-transition boundary of the direct injection device map. In one or all of the preceding examples, the update, in response to a fuel mass distance from the ballistic-to-transition boundary of the direct injection device map being less than the fuel mass distance from the lift-to-transition boundary of the direct injection device map, additionally or optionally involves decreasing the fuel mass of one of the multiple direct injections to move the fuel mass from the transition region into the ballistic region of the direct injection device map, while increasing the fuel mass of another of the multiple direct injections.In one or all of the preceding examples, updating in response to the fact that the distance of the fuel mass from the ballistic-to-transition boundary of the direct injection device map is greater than the distance of the fuel mass from a stroke-to-transition boundary of the direct injection device map further involves, additionally or optionally, increasing the fuel mass of one of the multiple direct injections to move the fuel mass from the transition region to the stroke region of the direct injection device map, while decreasing the fuel mass of another of the multiple direct injections. In one or all of the preceding examples, the increasing and decreasing are additionally or optionally based on a number of the multiple direct injections.In one or all of the preceding examples, updating the number of injections of the multiple direct injections additionally or optionally involves, during a first condition, decreasing the number of multiple injections by combining one of the multiple direct injections with at least one other of the multiple direct injections to move the fuel mass from the transition region to the lift region; and, during a second condition, increasing the number of multiple injections by splitting one of the multiple direct injections into a plurality of direct injections in the ballistic region. In one or all of the preceding examples, additionally or optionally, during the first condition, an unmatched number of multiple injections exceeds a threshold number, and during the second condition, the unmatched number of multiple injections exceeds the threshold number.In one or all of the preceding examples, the multiple direct injections additionally or optionally include multiple direct injections in an intake stroke and / or a compression stroke of the combustion cycle, and the updating further includes updating a split ratio of the directly injected fuel delivered in the intake stroke relative to the compression stroke. In one or all of the preceding examples, the method additionally or optionally further includes adjusting an amount of fuel delivered to the cylinder in the combustion cycle via port injection, based on the update. In one or all of the preceding examples, the method can additionally or optionally be implemented in a hybrid vehicle system.

[0104] Another exemplary method comprises: during a first condition, in response to the fact that a pulse width signal of a single direct injection fuel pulse of a combustion cycle lies within a transition region of a direct injection device, switching to operation with multiple direct injection fuel pulses in the combustion cycle, wherein the pulse width signal of each of the multiple direct injection fuel pulses lies outside the transition region; and during a second condition, in response to the fact that the pulse width signal of one of the multiple direct injection fuel pulses of the combustion cycle lies within the transition region, switching to operation with a single direct injection fuel pulse in the combustion cycle, wherein the pulse width signal of the single direct injection fuel pulse lies outside the transition region.In the preceding example, during the first condition, the pulse width signal of each of the multiple direct injection fuel pulses is additionally or optionally located in a ballistic region of the direct injection device, and during the second condition, the pulse width signal of the individual direct injection fuel pulse is located in a stroke region of the direct injection device. In one or all of the preceding examples, a total fuel mass delivered via direct injection in the combustion cycle is additionally or optionally maintained during each of the first and second conditions.In one or all of the preceding examples, the method additionally or optionally comprises, during a third condition, in response to the pulse width signal of one of the multiple direct injection fuel pulses of the combustion cycle being within the transition region of the direct injection device, adjusting the pulse width signal of each of the multiple direct injection fuel pulses to transition out of the transition region while maintaining a number of pulses of the multiple direct injection fuel pulses. In one or all of the preceding examples, the second condition additionally or optionally includes an engine speed above a threshold, and the third condition includes an engine speed below a threshold or an engine NVH level above a threshold.In one or all of the preceding examples, the switching and adjusting during each of the first, second and third conditions additionally or optionally involves adjusting a total fuel mass delivered via direct injection in the combustion cycle, the method further comprising adjusting a fuel mass delivered via port injection in the combustion cycle based on the adjusted total fuel mass delivered via direct injection.

[0105] Another exemplary system comprises: an internal combustion engine cylinder; a direct injection device for supplying fuel to the cylinder; and a controller with computer-readable instructions stored in non-volatile memory for: estimating an initial fuel injection profile for a combustion cycle of the cylinder based on the internal combustion engine speed / load and temperature, wherein the initial fuel injection profile includes multiple direct injection fuel pulses, with at least one of the multiple direct injection fuel pulses having a pulse width in a transition region of the direct injection device; during a first condition, modifying the initial fuel injection profile to a first modified fuel injection profile with a smaller number of multiple direct injection fuel pulses, each of the smaller number of multipledirect injection fuel pulses have a smaller pulse width in a stroke region of the direct injection device; and during a second condition, modifying the initial fuel injection profile to a second modified fuel injection profile, wherein the pulse width of a first set of the multiple direct injection fuel pulses is reduced in a ballistic region of the direct injection device, while the pulse width of a second set of the multiple direct injection fuel pulses is increased in the stroke region of the direct injection device, while maintaining a number of the multiple direct injection fuel pulses, wherein a total mass of directly injected fuel in each of the first and second modified fuel injection profiles is the same as the fuel mass in the initial fuel injection profile. In the preceding example, the first condition additionally or optionally includes aThe first condition involves an internal combustion engine speed above a threshold, and the second condition involves an internal combustion engine speed below a threshold. In one or all of the preceding examples, the multiple direct injection fuel pulses of the initial fuel injection profile additionally or optionally include an initial number of direct injection fuel pulses, and the modification during each of the first and second conditions is based on the initial number of direct injection fuel pulses and further on the pulse width of at least one of the multiple direct injection pulses relative to an upper pulse width limit of the ballistic region and a lower pulse width limit of the stroke region. In one or all of the preceding examples, the method additionally or optionally further comprises a port fuel injection device for supplying fuel to the cylinder, the control of which includes furtherInstructions include: during a third second condition, modifying the initial fuel injection profile to a third modified fuel injection profile, including adjusting the total mass of directly injected fuel to move the pulse width of at least one of the multiple direct injection fuel pulses out of the transition region of the direct injection device, and adjusting a port-injected fuel mass based on the adjusted direct-injected fuel mass.

[0106] Another example involving an internal combustion engine involves: estimating an initial ratio of port-injected fuel relative to direct-injected fuel in a combustion cycle based on the engine operating conditions; and, in response to the fact that direct fuel injection is in a transition region of a direct injection device map at the initial ratio, updating the initial ratio to move the direct fuel injection out of the transition region. In the preceding example, the transition region is additionally or optionally positioned between a ballistic region and a lift region of the direct injection device map, and direct injection device variability is higher in the transition region than in either the ballistic region or the lift region.In one or all of the preceding examples, the update is additionally or optionally based on a direct fuel injection pulse width relative to each of a ballistic-to-transition boundary and a lift-to-transition boundary of the direct injection device map. In one or all of the preceding examples, the update, in response to a direct fuel injection pulse width being less than the direct fuel injection pulse width being less than the lift-to-transition boundary of the direct injection device map, additionally or optionally involves decreasing a directly injected fuel mass to move the pulse width from the transition region to the ballistic region of the direct injection device map, while increasing a port-injected fuel mass.In one or all of the preceding examples, updating in response to a distance of the direct fuel injection pulse width from the ballistic-to-transition boundary of the direct injection device map being greater than the distance of the direct fuel injection pulse width from the lift-to-transition boundary of the direct injection device map involves, additionally or optionally, further increasing the directly injected fuel mass to move the pulse width from the transition region to the lift region of the direct injection device map while decreasing the port-injected fuel mass. In one or all of the preceding examples, the initial ratio of port-injected fuel to direct-injected fuel additionally or optionally involves multiple direct injections in the combustion cycle, and the increasing and decreasing are based on the number of these multiple direct injections.In one or all of the preceding examples, updating additionally or optionally involves further adjusting the number of multiple direct injections by decreasing the number of multiple direct injections to move the pulse width from the transition region to the lift region. In one or all of the preceding examples, decreasing the number of multiple direct injections additionally or optionally occurs in response to the fact that the unadjusted number of multiple direct injections exceeds a threshold. In one or all of the preceding examples, updating additionally or optionally involves further adjusting the number of multiple direct injections by increasing the number of multiple direct injections to move the pulse width from the transition region to the ballistic region.In one or all of the preceding examples, the increase occurs additionally or optionally in response to the fact that the unadjusted number of multiple direct injections falls below a threshold. In one or all of the preceding examples, the multiple direct injections additionally or optionally include multiple direct injections in an intake stroke and / or a compression stroke of the combustion cycle, and the update further includes updating a split ratio of the directly injected fuel delivered in the intake stroke relative to the compression stroke. In one or all of the preceding examples, the method can additionally or optionally be implemented in a hybrid vehicle system.

[0107] Another exemplary procedure comprises: during a first condition, in response to the fact that a pulse width of one of the multiple direct injection fuel pulses of a combustion cycle lies within a transition region of a direct injection device map, reducing a number of the multiple direct injection fuel pulses while maintaining a split ratio of directly injected to port-injected fuel; and during a second condition, in response to the fact that the pulse width of one of the multiple direct injection fuel pulses of the combustion cycle lies within the transition region of the direct injection device, adjusting the split ratio of directly injected to port-injected fuel.In one or all of the preceding examples, adjusting involves, when more power, charge cooling, or ignition advance is required, such as at higher internal combustion engine loads, additionally or optionally increasing the ratio of directly injected fuel to port-injected fuel over the combustion cycle, and at lower loads, when the FS load is above a threshold, decreasing the ratio of directly injected fuel to port-injected fuel over the combustion cycle.In one or all of the preceding examples, additionally or optionally, if more directly injected fuel mass is required to move one of the multiple direct injection fuel pulses out of the transition region, increase the split ratio of directly injected fuel to port-injected fuel over the combustion cycle; and if less directly injected fuel mass is required to move one of the multiple direct injection fuel pulses out of the transition region, decrease the split ratio of directly injected fuel to port-injected fuel over the combustion cycle. In one or all of the preceding examples, adjusting the split ratio additionally or optionally involves maintaining the number of multiple direct injection fuel pulses in the combustion cycle.In one or all of the preceding examples, adjusting the split ratio additionally or optionally involves adjusting the number of multiple direct injection fuel pulses in the combustion cycle, as well as a fuel mass delivered in each of the multiple direct injection fuel pulses. In one or all of the preceding examples, during the first condition, the pulse width of each of the reduced number of multiple direct injection fuel pulses additionally or optionally lies within a stroke region of the direct injection device. In one or all of the preceding examples, the first condition additionally or optionally involves a higher internal combustion engine load, and the second condition involves a lower internal combustion engine load.

[0108] Another exemplary internal combustion engine system comprises: an internal combustion engine cylinder; a direct injection device for supplying fuel to the cylinder; a port injection device for supplying fuel to the cylinder; and a controller with computer-readable instructions stored in non-volatile memory for: estimating an initial fuel injection profile for a combustion cycle of the cylinder based on the internal combustion engine speed / load and the internal combustion engine temperature, wherein the initial fuel injection profile has an initial split ratio of directly injected fuel to port-injected fuel delivered over several direct injection fuel pulses, wherein at least one of the several direct injection fuel pulses has a pulse width in a transition region of the direct injection device; and modifying the initial fuel injection profile.to modify the ratio of directly injected fuel to port-injected fuel such that at least one of the multiple direct injection fuel pulses is moved out of the transition region. In one or all of the preceding examples, modifying additionally or optionally involves increasing or decreasing a port-injected fuel mass relative to a total directly injected fuel mass based on the pulse width of at least one of the multiple direct injection pulses relative to an upper pulse width limit of a ballistic region and a lower pulse width limit of a stroke region of the direct injection device. In one or all of the preceding examples, decreasing the total directly injected fuel mass additionally or optionally involves decreasing a number of the multiple direct injection fuel pulses.to move the pulse width of each of the reduced number of direct injection fuel pulses into the stroke region, and wherein increasing the total mass of directly injected fuel involves increasing the number of multiple direct injection fuel pulses to move the pulse width of each of the increased number of direct injection fuel pulses into the ballistic region.

[0109] In another representation, the combustion engine is coupled in a hybrid vehicle system.

[0110] It should be noted that the control and estimation routines contained herein can be used with various internal combustion engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-volatile memory and can be executed by the control system, which includes the control unit in combination with the various sensors, actuators, and other internal combustion engine hardware. The specific routines described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Accordingly, various illustrated actions, operations, and / or functions can be performed in the illustrated sequence or in parallel, or in some cases, omitted.Likewise, the processing sequence is not strictly necessary to achieve the features and advantages of the embodiments described here, but is provided for easier illustration and description. One or more of the illustrated actions, operations, and / or functions can be performed repeatedly, depending on the specific strategy employed. Furthermore, the described actions, operations, and / or functions can graphically represent code that is to be programmed into non-volatile memory of the computer-readable storage medium in the internal combustion engine control system, wherein the described actions are executed by carrying out the instructions in a system that includes the various internal combustion engine hardware components in combination with the electronic control unit.

[0111] It is understood that the configurations and routines disclosed herein are exemplary and that these specific embodiments are not to be interpreted restrictively, as numerous variations are possible. For example, the foregoing technology can be applied to V-6, I-4, I-6, V-12, 4-cylinder boxer, and other types of internal combustion engines. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0112] The following claims describe, in particular, certain combinations and subcombinations that are considered novel and not obvious. These claims may refer to "one" element, "a first" element, or the equivalent thereof. Such claims should be understood as including one or more such elements and neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application.Such patent claims are also considered to be included in the subject matter of the present disclosure, irrespective of whether they have a broader, narrower, the same or a different scope of protection compared to the original patent claims.

Claims

[1] Method for an internal combustion engine, comprising: Delivering fuel to a cylinder in one combustion cycle as multiple direct injections; and In response to the fact that a fuel mass from one of the multiple direct injections is located in a transition region of a direct injection device map, updating one or more of a ratio of fuel delivered in each of the multiple direct injections and a number of multiple injections to move the fuel mass of one of the multiple direct injections out of the transition region. [2] Method according to claim 1, wherein the transition region is positioned between a ballistic region and a lift region of the direct injection device map and wherein direct injection device variability in the transition region is higher than in either the ballistic region and the lift region. [3] Method according to claim 2, wherein the updating is based on a position of the fuel mass relative to each of a ballistic-to-transition boundary and a stroke-to-transition boundary of the direct injection device map. [4] Method according to claim 3, wherein the updating in response to the fact that a distance of the fuel mass from the ballistic-to-transition boundary of the direct injection device map is less than the distance of the fuel mass from the stroke-to-transition boundary of the direct injection device map comprises decreasing the fuel mass of one of the multiple direct injections in order to move the fuel mass from the transition region to the ballistic region of the direct injection device map, while increasing the fuel mass of another of the multiple direct injections. [5] Method according to claim 4, wherein the updating in response to the fact that the distance of the fuel mass from the ballistic-to-transition boundary of the direct injection device map is greater than the distance of the fuel mass from a stroke-to-transition boundary of the direct injection device map further comprises increasing the fuel mass of one of the multiple direct injections in order to move the fuel mass from the transition region to the stroke region of the direct injection device map, while decreasing the fuel mass of another of the multiple direct injections. [6] Method according to claim 5, wherein the increase and decrease is based on a number of the multiple direct injections. [7] Method according to claim 1, wherein updating the number of injections of the multiple direct injections comprises: During a first condition, reducing the number of multiple injections by combining one of the multiple direct injections with at least one other of the multiple direct injections to move the fuel mass from the transition region to the stroke region; and During a second condition, increasing the number of multiple injections by splitting one of the multiple direct injections into a multitude of direct injections in the ballistic region. [8] Method according to claim 7, wherein during the first condition an unmatched number of the multiple injections is above a threshold number and wherein during the second condition the unmatched number of the multiple injections is above the threshold number. [9] Method according to claim 1, wherein the multiple direct injections include multiple direct injections in an intake stroke and / or a compression stroke of the combustion cycle and wherein the updating further includes updating a split ratio of the directly injected fuel that was delivered in the intake stroke relative to the compression stroke. [10] Method according to claim 1, further comprising adjusting an amount of fuel delivered to the cylinder in the combustion cycle via port fuel injection, based on updating. [11] Internal combustion engine system, comprising: an internal combustion engine cylinder; a direct injection device for supplying the cylinder with fuel; and a controller with computer-readable instructions stored in non-volatile memory for: Estimating an initial fuel injection profile for a combustion cycle of the cylinder based on the combustion engine speed / load and the combustion engine temperature, wherein the initial fuel injection profile includes multiple direct injection fuel pulses, wherein at least one of the multiple direct injection fuel pulses has a pulse width in a transition region of the direct injection device; During a first condition, modifying the initial fuel injection profile to a first modified fuel injection profile with a smaller number of multiple direct injection fuel pulses, each of the smaller number of multiple direct injection fuel pulses having a smaller pulse width in a full-stroke region of the direct injection device; and During a second condition, the initial fuel injection profile is modified to a second modified fuel injection profile, wherein the pulse width of a first set of the multiple direct injection fuel pulses is reduced into a ballistic region of the direct injection device, while the pulse width of a second set of the multiple direct injection fuel pulses is increased into the stroke region of the direct injection device, while a number of the multiple direct injection fuel pulses are maintained. [12] System according to claim 11, wherein the total mass of directly injected fuel in each of the first and second modified fuel injection profiles is the same as the fuel mass in the initial fuel injection profile. [13] System according to claim 11, wherein the first condition includes an internal combustion engine speed above a threshold and the second condition includes an internal combustion engine speed below a threshold. [14] System according to claim 11, wherein the multiple direct injection fuel pulses of the initial fuel injection profile include an initial number of direct injection fuel pulses and wherein the modification during each of the first and second conditions is based on the initial number of direct injection fuel pulses and further based on the pulse width of the at least one of the multiple direct injection pulses relative to an upper pulse width limit of the ballistic region and a lower pulse width limit of the stroke region. [15] System according to claim 11, further comprising a port fuel injection device for supplying the cylinder with fuel, wherein the control includes further instructions for: during a third second condition, modifying the initial fuel injection profile to a third modified fuel injection profile, including adjusting the total mass of directly injected fuel to move the pulse width of at least one of the multiple direct injection fuel pulses out of the transition region of the direct injection device, and adjusting a port-injected fuel mass based on the adjusted direct-injected fuel mass.

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