Vehicle Control Systems

Abstract

To provide a control system for a vehicle that comprises a control device which acquires engine drive force based upon request drive force that a driver of a vehicle comprising an internal combustion engine as a drive force source requests, and also controls, based upon the engine drive force, a fuel injection valve, a supercharge actuator and an EGR valve that the internal combustion engine comprises, and then can suppress a discharge amount of soot and generate the request drive force even when the driver makes a request for acceleration.SOLUTION: A vehicle comprises an electric motor as a different drive force source from an internal combustion engine, and a control device acquires engine drive force so that a fuel injection amount is smaller than a black smoke limit injection amount acquired based upon an oxygen amount and an oxygen concentration in an air cylinder, and then makes the electric motor generate drive force corresponding to a difference between the request drive force and engine drive force when limit drive force as the drive force that the internal combustion engine generates is smaller than the request drive force on condition that the fuel injection amount is equal to the black smoke limit injection amount.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a control system for a vehicle, for example, a control system for a vehicle including an internal combustion engine equipped with an EGR (Exhaust Gas Recirculation) device that recirculates part of the exhaust (combustion gas) to an intake path as EGR gas. [Background technology]

[0002] This type of vehicle control system controls the amount of EGR gas (EGR rate) in the cylinder (combustion chamber) so that the internal combustion engine generates the driving force (output) requested by the driver while suppressing the emission of NOx (nitrogen oxides). Generally, when the EGR rate decreases, the combustion speed of the mixture in the cylinder increases, increasing the driving force, but the temperature in the cylinder increases, increasing the NOx emissions (i.e., the amount of NOx contained in the exhaust). Therefore, one conventional vehicle control system obtains an EGR rate required for acceleration when the driver requests acceleration (i.e., an increase in driving force), and reduces the EGR rate based on the acceleration request EGR rate, thereby achieving a balance between ensuring driving force and suppressing NOx emissions (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-59443 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the fuel concentration in the air-fuel mixture in the cylinder increases, the amount of soot (particulate matter (PM)) emissions increases. Therefore, when acceleration is required, if the fuel injection amount is increased to generate the driving force required by the driver in the internal combustion engine, there is a risk that the amount of soot emissions will increase.

[0005] The present invention was devised in consideration of these points, and aims to provide a vehicle control system that can suppress soot emissions and generate the driving force requested by the driver even when acceleration is requested by the driver. [Means for solving the problem]

[0006] In order to solve the above problems, a vehicle control system according to a first aspect of the present invention comprises an internal combustion engine which is a driving force source of a vehicle, a fuel injection valve which injects fuel into a cylinder of the internal combustion engine, a turbine arranged in an exhaust passage of the internal combustion engine, a compressor arranged in an intake passage of the internal combustion engine and linked to the turbine, a supercharger which has a supercharging actuator for controlling the supercharging pressure which is the pressure of the intake air pressurized by the compressor, an EGR valve arranged in an EGR path which communicates the exhaust passage with the intake passage and recirculates a portion of the exhaust gas discharged from the cylinder as EGR gas, the opening of which is adjusted to control an EGR rate which correlates with the amount of EGR gas flowing into the cylinder, and a control device. The control device obtains a required driving force based on the acceleration required by the driver of the vehicle, obtains an engine driving force that is a target value of the driving force to be generated by the internal combustion engine based on the required driving force, obtains a fuel injection amount that is a target value of the fuel to be injected into the cylinder, a target boost pressure that is a target value of the boost pressure, and a target EGR rate that is a target value of the EGR rate based on the engine driving force, and controls the fuel injection valve, the boost actuator, and the EGR valve based on the fuel injection amount, the target boost pressure, and the target EGR rate.

[0007] Furthermore, the vehicle is equipped with an electric motor that is a driving force source different from the internal combustion engine, and the control device acquires the engine driving force so that the fuel injection amount is smaller than the black smoke limit injection amount acquired based on the amount of oxygen and oxygen concentration in the cylinder, and if the limiting driving force, which is the driving force generated by the internal combustion engine when the fuel injection amount is equal to the black smoke limit injection amount, is smaller than the required driving force, the control device causes the electric motor to generate a driving force equivalent to the difference between the required driving force and the engine driving force.

[0008] A second aspect of the present invention is a control system for a vehicle according to the first aspect of the present invention, wherein, when an acceleration control condition is met, which is met when the difference between the target boost pressure and the boost pressure is greater than a predetermined pressure threshold, the control device sets the EGR rate to a smaller value within a range of values ​​greater than an environmentally friendly EGR rate acquired based on an operating state of the internal combustion engine, compared to when the acceleration control condition is not met.

[0009] A third aspect of the present invention is a vehicle control system according to the first or second aspect, wherein the control device does not cause the electric motor to generate driving force when the required driving force is equal to or less than the limiting driving force. [Effects of the Invention]

[0010] In the vehicle control system according to the first aspect of the present invention, the fuel injection amount is prevented from exceeding the black smoke limit injection amount, i.e., the engine driving force is prevented from exceeding the limit driving force, making it possible to suppress soot emissions.

[0011] On the other hand, when the limiting driving force is smaller than the required driving force, the maximum value of the engine driving force (i.e., the driving force generated by the internal combustion engine when the fuel injection amount is equal to the black smoke limit injection amount) becomes smaller than the limiting driving force. In this case, the electric motor generates a driving force equivalent to the shortage of the engine driving force relative to the required driving force (i.e., the difference between the required driving force and the engine driving force). Therefore, it is possible for the internal combustion engine and the electric motor to generate the driving force required by the driver during acceleration.

[0012] In the second aspect of the present invention, the EGR rate is maintained at a value greater than the environmentally friendly EGR rate, thereby making it possible to suppress NOx emissions.

[0013] In the third aspect of the present invention, the electric motor generates driving force only when the required driving force is greater than the limit driving force, thereby preventing the electric power consumed by the electric motor from increasing more than necessary. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic configuration diagram of a vehicle to which a vehicle control system according to the present invention is applied; [Figure 2] 1 is a schematic configuration diagram of an engine system mounted on a vehicle. [Figure 3] 1 is a graph (map) showing the relationship between accelerator pedal opening Ap and engine rotation speed NE, and required driving force Dr. [Figure 4] 10 is a graph showing the relationship between the engine rotation speed NE, the intake air amount Ga, the EGR rate Er, and the limiting drive force Dg. [Figure 5] 4 is a graph showing the relationship between the engine driving force De and the atmospheric pressure Po, and the target supercharging pressure Ptgt. [Figure 6] 1 is a graph showing the relationship between atmospheric pressure Po, engine rotation speed NE, engine driving force De, and base EGR rate Eb. [Figure 7] 10 is a graph showing the relationship between the shift state of the transmission, the engine rotation speed NE, the accelerator pedal opening Ap, and the weighting coefficient k. [Figure 8] 4 is a time chart showing changes in each parameter as the accelerator pedal opening Ap increases. [Figure 9] 3 is a flowchart showing a "driving force control processing routine" executed by a control device of a vehicle control system. [Figure 10] 3 is a flowchart showing an "EGR valve control processing routine" executed by the control device. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of the present invention will be described with reference to FIGS. 1 to 10. The same reference numerals in the description refer to the same elements having the same functions without redundant description. A vehicle control system according to this embodiment is applied to a vehicle 1 shown in FIG. 1. The vehicle 1 includes an internal combustion engine 2, an electric motor 3, an ECU 4, front wheels 11a-11b, rear wheels 12a-12b, clutches 13a-13b, a transmission 14, a differential gear 15, a transmission shaft 16, a propeller shaft 17, a drive shaft 18, an inverter 31, and a battery 32.

[0016] The internal combustion engine 2 and the electric motor 3 are mounted on the vehicle 1 as a driving force source. That is, the vehicle 1 is a hybrid vehicle. The internal combustion engine 2 generates torque that rotates a crankshaft 2a. An engine system including the internal combustion engine 2 will be described later with reference to FIG. 2.

[0017] The electric motor 3 is a well-known three-phase synchronous generator-motor that can function as both an electric motor (motor) and a generator (generator). When operating as an electric motor, the electric motor 3 generates torque that rotates the electric motor shaft 3a. In this case, the inverter 31 converts DC power supplied from the battery 32 into three-phase AC power in response to instructions from the ECU 4 and supplies the AC power to the electric motor 3.

[0018] On the other hand, when the electric motor 3 operates as a generator, it converts torque that rotates the electric motor shaft 3a into electric power. In this case, the inverter 31 converts the three-phase AC power supplied from the electric motor 3 into DC power in response to an instruction from the ECU 4 and supplies the DC power to the battery 32. The battery 32 is a secondary battery (a lithium-ion battery in this embodiment) that can be charged and discharged.

[0019] The clutches 13a and 13b are switched between an engaged state and a disengaged state in response to a command from the ECU 4. When the clutch 13a is in an engaged state, the crankshaft 2a and the electric motor shaft 3a are connected to each other so that torque can be transmitted between them. When the clutch 13b is in an engaged state, the electric motor shaft 3a and the transmission shaft 16 are connected to each other so that torque can be transmitted between them.

[0020] The transmission 14 is a transmission that can change the gear ratio (specifically, the ratio of the rotational speed (input side rotational speed) of the transmission shaft 16 to the rotational speed (output side rotational speed) of the propeller shaft 17) between three stages in response to an instruction from the ECU 4. The speed change states of the transmission 14 are also referred to as "first speed," "second speed," and "third speed," in order from a state with a higher gear ratio to a state with a lower gear ratio.

[0021] The propeller shaft 17 and the drive shaft 18 are connected to each other via a differential gear 15 so as to be able to transmit torque to each other. The rear wheels 12a, 12b are drive wheels of the vehicle 1, and rotate together with the rotation of the drive shaft 18.

[0022] The ECU 4 is an electronic control unit (control device) that includes a CPU, ROM, RAM, and EEPROM. The CPU sequentially executes a predetermined program to read data, perform numerical calculations, and output the calculation results. The ROM stores the programs executed by the CPU and maps (lookup tables), etc. The RAM temporarily stores data referenced by the CPU. The EEPROM stores data referenced by the CPU and furthermore, retains the stored data even when the ECU 4 stops operating.

[0023] 2, the internal combustion engine 2 constitutes an engine system together with a turbocharger 5, an intake system 6, an exhaust system 7, and an EGR system 8. The internal combustion engine 2 includes a plurality of fuel injection valves 21. Each of the fuel injection valves 21 injects high-pressure fuel supplied from an accumulator chamber of a common rail device (not shown) into a cylinder (combustion chamber) in response to an instruction from an ECU 4.

[0024] The supercharger 5 includes a turbine 51, a variable nozzle mechanism 52, a nozzle actuator 52a, and a compressor 53. The turbine 51 is operated (rotated) by the pressure of the exhaust gas (combustion gas) discharged from each cylinder of the internal combustion engine 2. The variable nozzle mechanism 52 is equipped with a nozzle vane that is a mechanism for throttling the exhaust gas flowing into the turbine 51. For convenience, the variable nozzle mechanism 52 is also referred to as a "supercharging actuator."

[0025] Specifically, the degree of closure of the exhaust flow passage in the turbine 51 (i.e., the degree to which the exhaust flow passage is narrowed) changes according to the nozzle closure degree Vn, which is the state of the nozzle vane. The nozzle actuator 52a changes the nozzle closure degree Vn between a predetermined fully open position (fully open state) and a fully closed position (fully closed state) in accordance with an instruction from the ECU 4. The compressor 53 operates (rotates) in conjunction with the turbine 51, and pressurizes the air (intake air) drawn into each cylinder of the internal combustion engine 2.

[0026] The intake system 6 includes intake pipes 61a to 61b, which are intake passages, an intake manifold 62, an intercooler 63, a throttle valve 64, and a throttle actuator 64a. The intake pipe 61a introduces intake air (fresh air) drawn in from the outside (outside the vehicle) into the compressor 53. The intake pipe 61b introduces intake air discharged from the compressor 53 into the intake manifold 62. The intake manifold 62 introduces intake air into each cylinder of the internal combustion engine 2.

[0027] An intercooler 63 is disposed (mounted) in the intake pipe 61b. The intercooler 63 cools the intake air that has been pressurized by the compressor 53 and has a raised temperature. A throttle valve 64 is disposed in the intake pipe 61b at a position downstream of the intercooler 63. The throttle valve 64 adjusts the opening of the intake pipe 61b according to its rotational position. A throttle actuator 64a adjusts the rotational position of the throttle valve 64 according to a command from the ECU 4.

[0028] The exhaust system 7 includes an exhaust manifold 71, exhaust pipes 72a to 72b which are exhaust passages, and an exhaust gas purification device 73. The exhaust manifold 71 introduces exhaust (combustion gas) discharged from each cylinder of the internal combustion engine 2 into the exhaust pipe 72a. The exhaust pipe 72a introduces the exhaust to the turbine 51. The exhaust pipe 72b discharges the exhaust discharged from the turbine 51 to the outside (outside the vehicle). The exhaust gas purification device 73 is disposed in the exhaust pipe 72b. The exhaust gas purification device 73 includes a well-known oxidation catalyst, a DPF (Diesel Particulate Filter), an SCR (Selective Catalytic Reduction), etc., and purifies the exhaust gas.

[0029] The EGR system 8 includes an EGR pipe 81, an EGR cooler 82, and an EGR valve 83. The EGR pipe 81 is an EGR path that connects the exhaust pipe 72a and the intake pipe 61b. The EGR cooler 82 is disposed in the EGR pipe 81. The EGR cooler 82 cools the high-temperature exhaust gas (i.e., EGR gas) that flows in from the exhaust pipe 72a. The EGR valve 83 changes the opening degree of the EGR pipe 81 between a predetermined fully open state and a fully closed state in response to a command from the ECU 4. The EGR valve 83 adjusts the amount of EGR gas that flows back from the exhaust pipe 72a to the intake pipe 61b (specifically, the EGR rate Er, which is the concentration (mass ratio) of EGR gas in the air drawn into the cylinders of the internal combustion engine 2).

[0030] The ECU 4 is connected to a crank angle sensor 91 , a cam position sensor 92 , an airflow sensor 93 , a nozzle closure sensor 94 , pressure sensors 95 a to 95 c , temperature sensors 96 a to 96 b , an accelerator opening sensor 97 , and a vehicle speed sensor 98 .

[0031] The crank angle sensor 91 outputs a pulse signal to the ECU 4 every time the crankshaft 2a of the internal combustion engine 2 rotates by a predetermined angle. The cam position sensor 92 outputs a signal corresponding to the rotational position of a camshaft (not shown) of the internal combustion engine 2 to the ECU 4. The ECU 4 acquires the engine rotation speed NE of the internal combustion engine 2 based on the signal input from the crank angle sensor 91. The ECU 4 acquires the crank angle CA of a specific cylinder provided in the internal combustion engine 2 based on the signals input from the crank angle sensor 91 and the cam position sensor 92.

[0032] The airflow sensor 93 detects the intake air amount Ga, which is the amount of intake air flowing through the intake pipe 61a (specifically, mass per unit time), and outputs a signal representing the intake air amount Ga to the ECU 4. The nozzle closure degree sensor 94 detects the nozzle closure degree Vn, and outputs a signal representing the nozzle closure degree Vn to the ECU 4. The pressure sensor 95a is disposed in the intake pipe 61a at a position downstream of the airflow sensor 93. The pressure sensor 95a detects the atmospheric pressure Po, which is the pressure of the intake air flowing into the compressor 53, and outputs a signal representing the atmospheric pressure Po to the ECU 4.

[0033] The pressure sensor 95b is disposed in the intake pipe 61b at a position between the compressor 53 and the intercooler 63. The pressure sensor 95b detects a boost pressure Pbt, which is the pressure of the intake air flowing out from the compressor 53, and outputs a signal indicative of the boost pressure Pbt to the ECU 4. The pressure sensor 95c is disposed in the intake manifold 62. The pressure sensor 95c detects an intake manifold pressure Pm, which is the pressure of the intake air flowing into the cylinders of the internal combustion engine 2, and outputs a signal indicative of the intake manifold pressure Pm to the ECU 4.

[0034] The temperature sensor 96a is disposed in the intake pipe 61a at a position near the air flow sensor 93. The temperature sensor 96a detects an intake air temperature Ti, which is the temperature of the intake air flowing through the intake pipe 61a, and outputs a signal representing the intake air temperature Ti to the ECU 4. The temperature sensor 96b is disposed in the intake manifold 62. The temperature sensor 96b detects an intake manifold temperature Tm, which is the temperature of the intake air flowing into the cylinders of the internal combustion engine 2, and outputs a signal representing the intake manifold temperature Tm to the ECU 4.

[0035] The accelerator pedal position sensor 97 detects an accelerator pedal position Ap, which is the position of an accelerator pedal (not shown) operated by the driver to control the acceleration of the vehicle 1, and outputs a signal representing the accelerator pedal position Ap to the ECU 4. When the driver accelerates the vehicle 1 (i.e., when the required output of the internal combustion engine 2 (specifically, the required driving force Dr, which will be described later) increases), the accelerator pedal position Ap increases. The accelerator pedal position Ap is represented by a value ranging from 0% to 100%. The vehicle speed sensor 98 detects a vehicle speed Vs, which is the traveling speed of the vehicle 1, and outputs a signal representing the vehicle speed Vs to the ECU 4.

[0036] (Driving force control) While the vehicle 1 is traveling, the ECU 4 acquires (determines) the engine driving force De, which is a target value for the driving force (output) generated by the internal combustion engine 2, and the electric motor driving force Dm, which is a target value for the driving force generated by the electric motor 3. The ECU 4 acquires the fuel injection amount Qi according to the engine driving force De, and further determines a fuel injection pattern including (a plurality of) combinations of fuel injection timings represented by the crank angle CA and fuel injection amounts at those timings according to the fuel injection amount Qi. The ECU 4 injects fuel from the fuel injection valve 21 of each cylinder according to the fuel injection pattern. The fuel injection amount Qi increases as the engine driving force De increases.

[0037] On the other hand, the ECU 4 controls the inverter 31 so that the electric motor 3 generates a driving force equal to the electric motor driving force Dm. When the electric motor driving force Dm is "0", the ECU 4 does not cause the electric motor 3 to generate a driving force. That is, in this case, the vehicle 1 runs only by the driving force generated by the internal combustion engine 2. For convenience, the period during which the electric motor 3 generates a driving force (i.e., the period during which the electric motor driving force Dm is greater than "0") is also referred to as the "electric motor combined use period".

[0038] In addition, explanations regarding the "regenerative braking process" executed by the ECU 4, which causes the electric motor 3 to generate electricity when decelerating the vehicle 1, and the "forced charging process" which causes the electric motor 3 to generate electricity using the driving force generated by the internal combustion engine 2 when the stored charge (remaining capacity) of the battery 32 falls below a predetermined value, will be omitted in this specification.

[0039] The process executed by the ECU 4 to obtain the engine driving force De and the electric motor driving force Dm will be described in detail below. The ECU 4 obtains (determines) the required driving force Dr based on the accelerator pedal opening Ap and the engine speed NE. Specifically, the ECU 4 obtains the required driving force Dr by applying the accelerator pedal opening Ap and the engine speed NE to the relationship between the accelerator pedal opening Ap, the engine speed NE, and the required driving force Dr, as shown in Figure 3. As can be seen from Figure 3, the required driving force Dr increases as the accelerator pedal opening Ap increases, and the required driving force Dr increases as the engine speed NE increases.

[0040] In addition, the ECU 4 acquires a limiting driving force Dg. The limiting driving force Dg is a value acquired based on the amount of oxygen and the oxygen concentration in the cylinders of the internal combustion engine 2. For convenience, the fuel injection amount Qi when the engine driving force De is equal to the limiting driving force Dg is also referred to as the "black smoke limiting injection amount." If the fuel injection amount Qi becomes larger than the black smoke limiting injection amount (i.e., if the engine driving force De becomes larger than the limiting driving force Dg), there is a high possibility that the amount of soot (soot, particulate matter) contained in the exhaust will exceed a predetermined reference value (ambient black smoke reference value).

[0041] The limiting drive force Dg increases as the amount of oxygen in the cylinder of the internal combustion engine 2 increases (for example, as the intake air amount Ga increases). Furthermore, the limiting drive force Dg increases as the oxygen concentration in the cylinder increases (for example, as the EGR rate Er decreases). Specifically, the ECU 4 obtains the limiting drive force Dg by applying the engine speed NE, the intake air amount Ga, and the EGR rate Er to the relationship between the engine speed NE, the intake air amount Ga, the EGR rate Er, and the limiting drive force Dg, as shown in FIG.

[0042] When obtaining the limiting drive force Dg, the ECU 4 obtains (estimates) the EGR rate Er. Specifically, the ECU 4 estimates the total in-cylinder air amount Gg, which is the total mass of gas (fresh air and EGR gas) flowing into the cylinders of the internal combustion engine 2 per unit time, using a well-known method based on the intake air amount Ga, the boost pressure Pbt, the intake manifold pressure Pm, the intake air temperature Ti, the intake manifold temperature Tm, etc. In addition, the ECU 4 obtains the difference between the total in-cylinder air amount Gg and the intake air amount Ga as the EGR gas amount Ev, and further obtains the ratio of the EGR gas amount Ev to the total in-cylinder air amount Gg as the EGR rate Er (i.e., Er = Ev / Gg = (Gg - Ga) / Gg).

[0043] If the required driving force Dr is less than or equal to the limit driving force Dg, the ECU 4 sets the engine driving force De to a value equal to the required driving force Dr. In this case, the ECU 4 sets the electric motor driving force Dm to "0." On the other hand, if the required driving force Dr is greater than the limit driving force Dg, the ECU 4 sets the engine driving force De to a value equal to the limit driving force Dg. In this case, the ECU 4 sets the electric motor driving force Dm to a value equal to the difference between the required driving force Dr and the limit driving force Dg (i.e., Pm = Pr - Pg). In other words, the electric motor driving force Dm is equal to the difference between the required driving force Dr and the engine driving force De.

[0044] When the engine driving force De is acquired, the ECU 4 acquires a target boost pressure Ptgt, which is a target value of the boost pressure Pbt, and a target EGR rate Etgt, which is a target value of the EGR rate Er. The ECU 4 acquires the target boost pressure Ptgt based on the engine driving force De and the atmospheric pressure Po.

[0045] Specifically, the ECU 4 obtains the target boost pressure Ptgt by applying the engine driving force De and the atmospheric pressure Po to the relationship between the engine driving force De, the atmospheric pressure Po, and the target boost pressure Ptgt, as shown in Fig. 5. The pressure p1 shown in Fig. 5 (and Fig. 6, which will be described later) is equal to the atmospheric pressure Po at sea level (i.e., standard atmospheric pressure, 1 atmosphere). As can be seen from Fig. 5, the target boost pressure Ptgt increases as the engine driving force De increases, and decreases as the atmospheric pressure Po decreases.

[0046] Once the target boost pressure Ptgt is acquired, the ECU 4 performs feedback control of the nozzle closure degree Vn so that the boost pressure Pbt approaches the target boost pressure Ptgt. Specifically, the ECU 4 acquires a nozzle change amount ΔVn, which is the amount of change in the nozzle closure degree Vn, according to a pressure difference Pdif (i.e., Pdif=Ptgt−Pbt), which is the difference between the target boost pressure Ptgt and the boost pressure Pbt. In addition, the ECU 4 controls the nozzle actuator 52a to change the nozzle closure degree Vn by the nozzle change amount ΔVn.

[0047] Next, a method for obtaining the target EGR rate Etgt will be described. If the "acceleration control condition" is not satisfied, the ECU 4 sets the target EGR rate Etgt to a value equal to a base EGR rate Eb, which will be described later. The acceleration control condition is satisfied when the pressure difference Pdif is greater than a predetermined pressure threshold Pth (i.e., Pdif = Ptgt - Pbt > Pth). In other words, the acceleration control condition is satisfied when the boost pressure Pbt has not yet risen sufficiently after the driver increases the accelerator pedal opening Ap to request acceleration of the vehicle 1 (i.e., after the target boost pressure Ptgt has increased). For convenience, the period during which the acceleration control condition is satisfied is also referred to as the "acceleration control period."

[0048] The ECU 4 obtains the base EGR rate Eb by applying the atmospheric pressure Po, the engine speed NE, and the engine driving force De to the relationship between the atmospheric pressure Po, the engine speed NE, the engine driving force De, and the base EGR rate Eb, as illustrated in Fig. 6. The relationship between the atmospheric pressure Po, the engine speed NE, the engine driving force De, and the base EGR rate Eb is adapted in advance so that the amounts of NOx and soot contained in the exhaust gas of the internal combustion engine 2 are reduced and the fuel economy of the internal combustion engine 2 is improved when the boost pressure Pbt is equal to the target boost pressure Ptgt and the EGR rate Er is equal to the base EGR rate Eb.

[0049] In this embodiment, the base EGR rate Eb is set to a smaller value as the atmospheric pressure Po decreases, which prevents the output of the internal combustion engine 2 from being excessively reduced when the vehicle 1 travels at high altitudes where the atmospheric pressure Po is relatively low.

[0050] For example, the solid line La shown in Fig. 6 represents a set of combinations of the engine speed NE and the engine driving force De at which the base EGR rate Eb is equal to the value e2 when the atmospheric pressure Po is equal to the pressure p1. Point Pa is a point on the solid line La (i.e., a combination of the engine speed NE and the engine driving force De). Therefore, when the atmospheric pressure Po is equal to the pressure p1 and the engine speed NE and the engine driving force De are each equal to the value represented by point Pa, the base EGR rate Eb is equal to the value e2.

[0051] On the other hand, the dashed line Lb represents a set of combinations of the engine speed NE and the engine driving force De where the base EGR rate Eb is equal to the value e2 when the atmospheric pressure Po is equal to the pressure p2 (which is lower than the pressure p1). Therefore, when the atmospheric pressure Po is equal to the pressure p2 and the engine speed NE and the engine driving force De are each equal to the values ​​represented by the point Pa, the base EGR rate Eb is greater than the value e1 and smaller than the value e2. In other words, if the engine speed NE and the engine driving force De are the same, when the atmospheric pressure Po drops from the pressure p1 to the pressure p2, the base EGR rate Eb decreases.

[0052] However, the ECU 4 controls the EGR valve 83 so that the EGR rate Er does not become smaller than an environmentally friendly EGR rate Emin, which will be described later. Specifically, the ECU 4 obtains the smaller of the target EGR rate Etgt and the environmentally friendly EGR rate Emin as the final EGR rate Efin, and performs feedback control on the EGR valve 83 so that the EGR rate Er approaches the final EGR rate Efin. For convenience, the final EGR rate Efin used to control the EGR valve 83 is also referred to as the "target EGR rate."

[0053] The ECU 4 obtains the environmentally safe EGR rate Emin by applying the atmospheric pressure Po, the engine speed NE, and the engine driving force De to the relationship between the atmospheric pressure Po, the engine speed NE, the engine driving force De, and the environmentally safe EGR rate Emin (as with the base EGR rate Eb). The environmentally safe EGR rate Emin is set to a value smaller than the base EGR rate Eb. For example, the dashed dotted line Lc shown in FIG. 6 represents a set of combinations of the engine speed NE and the engine driving force De at which the environmentally safe EGR rate Emin is equal to the value e2 when the atmospheric pressure Po is equal to the pressure p1. If the EGR rate Er is smaller than the environmentally safe EGR rate Emin, the amount of NOx contained in the exhaust gas is more likely to exceed a predetermined standard value (environmental NOx standard value).

[0054] On the other hand, when the acceleration control condition is satisfied, the ECU 4 obtains the target EGR rate Etgt based on the base EGR rate Eb, the acceleration required EGR rate Eacc, and the weighting coefficient k. The ECU 4 obtains the acceleration required EGR rate Eacc based on the acceleration required driving force Dacc.

[0055] The ECU 4 acquires the acceleration required driving force Dacc based on the pressure difference Pdif. Specifically, the ECU 4 sets the acceleration required driving force Dacc to a larger value as the pressure difference Pdif increases. Therefore, when the driver requests acceleration of the vehicle 1 (i.e., when the target boost pressure Ptgt increases), if the increase in the boost pressure Pbt is delayed due to turbo lag (boost delay), the acceleration required driving force Dacc becomes a relatively large value.

[0056] The ECU 4 obtains the acceleration required EGR rate Eacc by applying the atmospheric pressure Po, the engine rotation speed NE, and the engine driving force De to the relationship between the acceleration required EGR rate Eacc and the atmospheric pressure Po, the engine rotation speed NE, and the engine driving force De (similar to the base EGR rate Eb). The ECU 4 sets the acceleration required EGR rate Eacc to a value smaller than the base EGR rate Eb, and sets the acceleration required EGR rate Eacc to a smaller value as the acceleration required driving force Dacc becomes larger. Furthermore, the ECU 4 sets the acceleration required EGR rate Eacc to a smaller value as the atmospheric pressure Po becomes smaller.

[0057] In addition, the ECU 4 obtains the weighting coefficient k by applying the gear shift state of the transmission 14, the engine rotation speed NE, and the accelerator pedal opening degree Ap to the relationship between the gear shift state of the transmission 14 (i.e., one of the first speed, second speed, and third speed), the engine rotation speed NE, the accelerator pedal opening degree Ap, and the weighting coefficient k, as illustrated in Fig. 7. The weighting coefficient k is a value greater than "0" and less than "1" (i.e., 0 <k<1)。

[0058] The ECU 4 sets the weighting factor k to a larger value as the increase in the vehicle speed Vs requested by the driver of the vehicle 1 (i.e., the acceleration of the vehicle 1) increases. Specifically, the ECU 4 sets the weighting factor k to a smaller value as the engine rotation speed NE increases, and sets the weighting factor k to a larger value as the accelerator pedal opening degree Ap increases. In addition, the ECU 4 sets the weighting factor k to a larger value as the gear ratio decreases (i.e., as the vehicle speed Vs becomes more difficult to increase).

[0059] Furthermore, the ECU 4 acquires (calculates) the target EGR rate Etgt by applying the base EGR rate Eb, the acceleration required EGR rate Eacc, and a weighting coefficient k to the following equation (1). As can be seen from equation (1), the difference between the acceleration required EGR rate Eacc and the target EGR rate Etgt decreases as the weighting coefficient k increases. In other words, the target EGR rate Etgt decreases as the weighting coefficient k increases. Etgt=Eacc×k+Eb×(1-k) ……(1)

[0060] Even when the acceleration control condition is satisfied (similar to the case where the acceleration control condition is not satisfied), the ECU 4 controls the EGR valve 83 so that the EGR rate Er does not become smaller than the environmentally safe EGR rate Emin. That is, the ECU 4 obtains the smaller value of the target EGR rate Etgt and the environmentally safe EGR rate Emin as the final EGR rate Efin, and controls the EGR valve 83 so that the EGR rate Er approaches the final EGR rate Efin.

[0061] In other words, regardless of whether the acceleration control condition is satisfied, the ECU 4 maintains the EGR rate Er at or above the environmental guarantee EGR rate Emin to prevent the amount of NOx contained in the exhaust from exceeding the environmental NOx standard value. In addition, the ECU 4 maintains the engine driving force De at or below the limit driving force Dg to prevent the amount of soot contained in the exhaust from exceeding the environmental black smoke standard value. Furthermore, when the acceleration control condition is satisfied, the ECU 4 sets the target EGR rate Etgt to a small value (compared to when the acceleration control condition is not satisfied) to promote an increase in the engine rotation speed NE (and therefore an increase in the vehicle speed Vs).

[0062] (Time chart) The final EGR rate Efin, which is determined based on whether the acceleration control conditions are satisfied, will be specifically described with reference to the example of Fig. 8. During the period shown in Fig. 8, the vehicle 1 is traveling at high altitude where the atmospheric pressure Po is lower than the pressure p1, and the gear shift state of the transmission 14 is maintained in second gear. In addition, the clutches 13a and 13b are maintained in an engaged state.

[0063] As shown by the solid line L1 in Figure 8, the accelerator pedal depression Ap starts to increase at time t1 and reaches 100% at time t4. As the accelerator pedal depression Ap increases, the required driving force Dr increases, as shown by the solid line L2a.

[0064] As a result, from time t3 onwards (until time t6), the required driving force Dr is greater than the limiting driving force Dg indicated by dashed line L2b. That is, the period from time t3 to time t6 corresponds to the electric motor combined use period. Therefore, during the period from time t3 to time t6, the engine driving force De is set to a value equal to the limiting driving force Dg, and the electric motor driving force Dm is set to a value equal to the difference between the required driving force Dr and the limiting driving force Dg.

[0065] The target boost pressure Ptgt, indicated by the solid line L3a, increases due to an increase in the engine driving force De accompanying an increase in the accelerator pedal opening Ap. Meanwhile, the boost pressure Pbt, indicated by the dashed line L3b, increases relatively slowly due to the low atmospheric pressure Po. Therefore, from time t2 onward (until time t7), the pressure difference Pdif is greater than the pressure threshold Pth. That is, the acceleration control condition is met during the period from time t2 to time t7. In other words, the period from time t2 to time t7 corresponds to the acceleration control period. Therefore, the acceleration required driving force Dacc, indicated by the dashed line L2c, is acquired during the period from time t2 to time t7.

[0066] After time t8, the boost pressure Pbt becomes substantially equal to the target boost pressure Ptgt (see solid line L3a and dashed line L3b). Then, at time t9, the accelerator pedal opening Ap decreases from 100% (see solid line L1), causing the required driving force Dr (and thus the engine driving force De), the target boost pressure Ptgt, and the boost pressure Pbt to all decrease (see solid lines L2a, L3a, and dashed line L3b). Due to the increase in engine driving force De (and the generation of driving force by electric motor 3 during the electric motor concurrent use period), the engine speed NE, shown by solid line L4, increases until time t9 and then decreases after time t9.

[0067] Meanwhile, in the period up to time t9, as the engine driving force De increases, the base EGR rate Eb indicated by the dashed line L5a decreases. Similarly, the environmentally friendly EGR rate Emin indicated by the dashed line L5b decreases (within a range of values ​​smaller than the base EGR rate Eb). As described above, the acceleration control condition is met in the period from time t2 to time t7, and therefore the acceleration required EGR rate Eacc is acquired as indicated by the dashed line L5c.

[0068] During the period from time t2 to time t5, the acceleration required EGR rate Eacc is smaller than the environmentally safe EGR rate Emin. On the other hand, during the period from time t5 to time t7, the acceleration required EGR rate Eacc is larger than the environmentally safe EGR rate Emin. Therefore, the final EGR rate Efin indicated by the (discontinuous) solid line L5d is equal to the environmentally safe EGR rate Emin during the period from time t2 to time t5, and is equal to the acceleration required EGR rate Eacc during the period from time t5 to time t7.

[0069] On the other hand, when the acceleration control condition is not satisfied (i.e., during the period up to time t2 and the period after time t7), the final EGR rate Efin is set to a value equal to the base EGR rate Eb (which is greater than the environmentally friendly EGR rate Emin) (see dashed line L5a and solid line L5d).

[0070] (Specific operation) Next, we will explain the specific operation of the ECU 4. The CPU of the ECU 4 (hereinafter also referred to as the unit "CPU") executes a "driving force control processing routine" shown in the flowchart of Fig. 9 every time a predetermined time period elapses.

[0071] When the appropriate timing arrives, the CPU starts processing from step 900 in Figure 9 and proceeds to step 905, where it obtains the required driving force Dr by applying the accelerator pedal opening Ap and the engine speed NE to the relationship shown in Figure 3. Next, the CPU proceeds to step 910, where it obtains the limiting driving force Dg by applying the engine speed NE, the intake air amount Ga, and the EGR rate Er to the relationship shown in Figure 4.

[0072] The CPU then proceeds to step 915 to determine whether the required driving force Dr is greater than the limit driving force Dg. That is, the CPU determines whether the current time is the electric motor combined use period. If the required driving force Dr is greater than the limit driving force Dg, the CPU determines "Yes" in step 915 and executes the processes of steps 920 to 955 in order, and then proceeds to step 995 to end the processing of this routine.

[0073] Step 920: The CPU sets the engine driving force De to a value equal to the limiting driving force Dg. Step 925: The CPU sets the electric motor driving force Dm to a value equal to the difference between the requested driving force Dr and the limiting driving force Dg. Step 930: The CPU obtains the fuel injection amount Qi and the target boost pressure Ptgt based on the engine driving force De. At this time, the CPU obtains the target boost pressure Ptgt by applying the engine driving force De and the atmospheric pressure Po to the relationship shown in FIG.

[0074] Step 935: The CPU sets the pressure difference Pdif to a value equal to the difference between the target boost pressure Ptgt and the boost pressure Pbt. Step 940: The CPU acquires the nozzle variation amount ΔVn based on the pressure difference Pdif. Specifically, if the pressure difference Pdif is a positive value (i.e., if the target boost pressure Ptgt is greater than the boost pressure Pbt), the CPU sets the nozzle variation amount ΔVn to a positive value, and if the pressure difference Pdif is a negative value, the CPU sets the nozzle variation amount ΔVn to a negative value. However, if the magnitude |Pdif| of the pressure difference Pdif is smaller than a predetermined value (a small value), the CPU sets the nozzle variation amount ΔVn to "0."

[0075] Step 945: The CPU controls the variable nozzle mechanism 52 based on the nozzle change amount ΔVn. Specifically, the CPU controls the nozzle actuator 52a so that the nozzle closure degree Vn changes by the nozzle change amount ΔVn. For example, if the nozzle change amount ΔVn is a positive value (i.e., if the target boost pressure Ptgt is greater than the boost pressure Pbt), the nozzle closure degree Vn increases. Therefore, the exhaust flow path in the turbine 51 becomes more constricted.

[0076] Step 950: The CPU executes an EGR valve control process, specifically, the EGR valve control process shown in the flowchart of FIG. Step 955: The CPU causes the electric motor 3 to generate a driving force equal to the electric motor driving force Dm. Specifically, the CPU controls the inverter 31 to adjust the power supplied from the battery 32 to the electric motor 3.

[0077] On the other hand, if the requested driving force Dr is equal to or less than the limiting driving force Dg, the CPU determines "No" at step 915 and proceeds to step 960, where it sets the engine driving force De to a value equal to the limiting driving force Dg. Next, the CPU proceeds to step 965, where it sets the electric motor driving force Dm to "0." Then, the CPU proceeds to step 930.

[0078] Next, the "EGR valve control processing routine" shown in the flowchart of Fig. 10 will be described. When the CPU proceeds to step 950, it starts the processing from step 1000 in Fig. 10 and proceeds to step 1005, where it obtains the base EGR rate Eb and the environmentally friendly EGR rate Emin based on the operating state of the internal combustion engine 2. Specifically, the CPU obtains the base EGR rate Eb by applying the atmospheric pressure Po, the engine rotation speed NE, and the engine driving force De to the relationship shown in Fig. 6. Similarly, the CPU obtains the environmentally friendly EGR rate Emin based on the atmospheric pressure Po, the engine rotation speed NE, and the engine driving force De.

[0079] Next, the CPU proceeds to step 1010 and determines whether the acceleration control condition is met. That is, the CPU determines whether the pressure difference Pdif is greater than the pressure threshold Pth. If the acceleration control condition is met, the CPU determines "Yes" in step 1010 and executes the processes of steps 1015 to 1030 in order, and then proceeds to step 1035.

[0080] On the other hand, if the acceleration control condition is not satisfied, the CPU determines "No" in step 1010 and proceeds to step 1050, where it sets the target EGR rate Etgt to a value equal to the base EGR rate Eb. Next, the CPU proceeds directly to step 1035.

[0081] Step 1015: The CPU obtains the acceleration required driving force Dacc based on the pressure difference Pdif. Step 1020: The CPU obtains the acceleration required EGR rate Eacc based on the atmospheric pressure Po, the engine rotation speed NE, and the engine driving force De (as well as the base EGR rate Eb and the environmentally friendly EGR rate Emin).

[0082] Step 1025: The CPU obtains the weighting coefficient k by applying the gear shift state of the transmission 14, the engine rotation speed NE, and the accelerator pedal opening Ap to the relationship shown in FIG. Step 1030: The CPU obtains the target EGR rate Etgt by applying the base EGR rate Eb, the acceleration required EGR rate Eacc, and the weighting coefficient k to the above equation (1).

[0083] In step 1035, the CPU determines whether the target EGR rate Etgt is smaller than the environmentally safe EGR rate Emin. If the target EGR rate Etgt is smaller than the environmentally safe EGR rate Emin, the CPU determines "Yes" in step 1035 and proceeds to step 1040, where it sets the final EGR rate Efin to a value equal to the environmentally safe EGR rate Emin. Then, the CPU proceeds to step 1045.

[0084] On the other hand, if the target EGR rate Etgt is equal to or greater than the environmentally friendly EGR rate Emin, the CPU determines "No" in step 1035 and proceeds to step 1055, where it sets the final EGR rate Efin to a value equal to the target EGR rate Etgt. Next, the CPU proceeds to step 1045.

[0085] In step 1045, the CPU controls the EGR valve 83 so that the EGR rate Er approaches the final EGR rate Efin. Specifically, the CPU obtains an EGR rate difference Edif, which is the difference between the final EGR rate Efin and the EGR rate Er (i.e., Edif=Efin-Er), and performs feedback control of the EGR valve 83 in accordance with the EGR rate difference Edif. That is, the same processing as that of steps 940 and 950 in FIG. 9, which is executed for the nozzle actuator 52a, is executed for the EGR valve 83.

[0086] Next, the CPU proceeds to step 1095, terminates the processing of this routine, and proceeds to step 955 in FIG.

[0087] The CPU executes a routine not shown to control the gear shift state of the transmission 14 (i.e., first, second, or third gear) and the state of the clutches 13a and 13b (i.e., either the engaged state or the disengaged state) based on the vehicle speed Vs, the accelerator pedal opening Ap, etc.

[0088] As described above, the vehicle control system according to this embodiment prevents the EGR rate Er from becoming smaller than the environmentally friendly EGR rate Emin, and prevents the engine driving force De from becoming larger than the limit driving force Dg (i.e., the fuel injection amount Qi from becoming larger than the black smoke limit injection amount). In addition, when the required driving force Dr is larger than the limit driving force Dg, the electric motor 3 generates driving force, so that even if the pressure difference Pdif becomes relatively large due to turbo lag, the difference between the required driving force Dr and the driving force of the vehicle 1 (i.e., the sum of the output of the internal combustion engine 2 and the output of the electric motor 3) is prevented from becoming large.

[0089] For example, if the target boost pressure Ptgt increases while the vehicle 1 is traveling at high altitudes where the atmospheric pressure Po is lower than pressure p1, the boost pressure Pbt increases more slowly than when traveling at low altitudes where the atmospheric pressure Po is equal to pressure p1, and the acceleration control condition is met more frequently. If the amount of oxygen in the cylinders of the internal combustion engine 2 becomes smaller than the desired value (specifically, the amount of oxygen in the cylinders when the boost pressure Pbt is equal to the target boost pressure Ptgt) due to the slow increase in the boost pressure Pbt, the limited driving force Dg decreases, and it is likely to become smaller than the required driving force Dr. In such a case, the electric motor driving force Dm is set to a value greater than "0" and the electric motor 3 generates driving force.

[0090] In addition, the target boost pressure Ptgt is set to a smaller value as the atmospheric pressure Po decreases (see FIG. 5). Therefore, when the vehicle 1 is traveling at high altitudes where the atmospheric pressure Po is lower than the pressure p1, it is possible to avoid applying an excessive load to the turbocharger 5 in order to make the boost pressure Pbt equal to the target boost pressure Ptgt. For example, it is possible to avoid the rotation speeds of the turbine 51 and the compressor 53 becoming excessively high and the temperature of the turbine 51 becoming excessively high, which would otherwise occur if an attempt were made to increase the boost pressure Pbt in an environment where the atmospheric pressure Po is lower than the pressure p1.

[0091] On the other hand, the base EGR rate Eb and the acceleration required EGR rate Eacc are set to smaller values ​​as the atmospheric pressure Po decreases. Therefore, the final EGR rate Efin decreases as the atmospheric pressure Po decreases, within a range of values ​​greater than the environmentally safe EGR rate Emin. Therefore, even when the vehicle 1 is traveling at a high altitude where the atmospheric pressure Po is lower than the pressure p1, a decrease in the engine driving force De is avoided as much as possible.

[0092] If control is executed to lengthen the electric motor concurrent use period and / or to increase the electric motor driving force Dm compared to when atmospheric pressure Po is equal to pressure p1, with the start condition being that atmospheric pressure Po is lower than a predetermined threshold value that is lower than pressure p1, there is a high possibility that the amount of electricity stored in battery 32 will decrease early. On the other hand, according to the vehicle control system of this embodiment, when requested driving force Dr is equal to or less than limiting driving force Dg, electric motor driving force Dm is set to "0," thereby minimizing consumption of the electric power charged in battery 32.

[0093] While the embodiments of the present invention have been described above with reference to the above structures, it will be apparent to those skilled in the art that many alternatives, improvements, and modifications may be made without departing from the scope of the present invention. Accordingly, the present invention encompasses all alternatives, improvements, and modifications that do not depart from the spirit and scope of the appended claims. The present invention is not limited to the specific structures described above, and may be modified, for example, as follows:

[0094] During the electric motor combined use period (i.e., when the required driving force Dr is greater than the limit driving force Dg), the ECU 4 sets the engine driving force De to a value equal to the limit driving force Dg and sets the electric motor driving force Dm to a value equal to the difference between the required driving force Dr and the limit driving force Dg. Alternatively, during the electric motor combined use period, the ECU 4 may set the engine driving force De to a value smaller than the limit driving force Dg by a predetermined adjustment driving force Dd (i.e., De = Dg - Dd) and set the electric motor driving force Dm to a value obtained by adding the adjustment driving force Dd to the difference between the required driving force Dr and the limit driving force Dg (i.e., Dm = Dr - Dg + Dd).

[0095] The ECU 4 sets the target boost pressure Ptgt to a smaller value as the atmospheric pressure Po becomes smaller. Alternatively, or in addition to this, when a predetermined booster load condition that is satisfied when an excessive load is applied to the turbocharger 5 is satisfied, the ECU 4 may set the target boost pressure Ptgt to a smaller value compared to when the turbocharger load condition is not satisfied. In this aspect, when the turbocharger load condition is satisfied, the target boost pressure Ptgt becomes smaller, and the load applied to the turbocharger 5 decreases. At that time, the boost pressure Pbt becomes smaller, and the limiting drive force Dg becomes smaller.

[0096] In the vehicle 1, both the driving force generated by the internal combustion engine 2 and the driving force generated by the electric motor 3 are transmitted to the rear wheels 12a, 12b. Alternatively, the vehicle 1 may be configured so that one of the driving force generated by the internal combustion engine 2 and the driving force generated by the electric motor 3 is transmitted to the front wheels 11a, 11b, and the other is transmitted to the rear wheels 12a, 12b.

[0097] The ECU 4 has acquired (estimated) the EGR rate Er based on the intake air amount Ga, the boost pressure Pbt, the intake manifold pressure Pm, the intake air temperature Ti, the intake manifold temperature Tm, etc. Alternatively, the vehicle 1 may be configured such that a sensor (gas flow sensor) that detects the EGR gas flow rate Ge is disposed in the EGR pipe 81, and the ECU 4 acquires the EGR rate Er based on the intake air amount Ga and the EGR gas flow rate Ge.

[0098] The pressure sensor 95a that detects the atmospheric pressure Po is disposed in the intake pipe 61a. Alternatively, the pressure sensor 95a may be disposed at a position where it can detect the atmospheric pressure around (outside) the engine system including the internal combustion engine 2.

[0099] The above-described processing performed by the ECU 4 may be executed by a plurality of ECUs. [Explanation of symbols]

[0100] 1...Vehicle 2...Internal combustion engine 2a...Crankshaft 3...Electric motor 3a...Motor shaft 4...ECU 5...Turbocharger 6...Intake system 7...Exhaust system 8...EGR system 11a, 11b...front wheel 12a, 12b...Rear wheel 13a, 13b...Clutch 14...Transmission 15...Differential gear 16...Transmission shaft 17...Propeller shaft 18...Drive shaft 21...Fuel injection valve 31...Inverter 32...Battery 51...Turbine 52...Variable nozzle mechanism 52a...Nozzle actuator 53...Compressor 61a, 61b...intake pipe 62...Intake manifold 63...Intercooler 64...Throttle valve 64a...Throttle actuator 71...Exhaust manifold 72a, 72b...Exhaust pipe 73...Exhaust gas purification equipment 81...EGR tube 82...EGR cooler 83...EGR valve 91...Crank angle sensor 92...Camera position sensor 93...Air flow sensor 94...Nozzle closure sensor 95a~95c...Pressure sensors 96a, 96b...Temperature sensors 97...Accelerator opening sensor 98...Vehicle speed sensor

Claims

1. an internal combustion engine that is a driving force source for the vehicle; a fuel injection valve that injects fuel into a cylinder of the internal combustion engine; a turbocharger including a turbine disposed in an exhaust passage of the internal combustion engine, a compressor disposed in an intake passage of the internal combustion engine and interlocked with the turbine, and a turbocharger actuator for controlling a supercharging pressure, which is the pressure of intake air pressurized by the compressor; an EGR valve disposed in an EGR path that connects the exhaust passage and the intake passage and recirculates a portion of the exhaust gas discharged from the cylinder as EGR gas, the opening of which is adjusted to control an EGR rate that correlates with the amount of EGR gas flowing into the cylinder; obtaining a required driving force based on an acceleration required by a driver of the vehicle; acquiring an engine driving force that is a target value of the driving force to be generated by the internal combustion engine based on the required driving force; acquiring a fuel injection amount that is a target value of fuel to be injected into the cylinder based on the engine driving force, a target boost pressure that is a target value of the boost pressure, and a target EGR rate that is a target value of the EGR rate; a control device that controls the fuel injection valve, the supercharging actuator, and the EGR valve based on the fuel injection amount, the target supercharging pressure, and the target EGR rate; A vehicle control system comprising: The vehicle is an electric motor that is a driving force source different from the internal combustion engine; The control device The engine driving force is obtained so that the fuel injection amount is smaller than a black smoke limit injection amount obtained based on the oxygen amount and oxygen concentration in the cylinder. If a limiting driving force, which is a driving force generated by the internal combustion engine when the fuel injection amount is equal to the black smoke limit injection amount, is smaller than the required driving force, a driving force equivalent to a difference between the required driving force and the engine driving force is generated in the electric motor, When an acceleration control condition is satisfied, which is satisfied when the difference between the target boost pressure and the boost pressure is larger than a predetermined pressure threshold value, the EGR rate is set to a smaller value within a range of values ​​larger than an environmentally friendly EGR rate acquired based on an operating state of the internal combustion engine, compared to when the acceleration control condition is not satisfied. Vehicle control system.

2. 2. The vehicle control system according to claim 1, The control device A vehicle control system that prevents the electric motor from generating a driving force when the required driving force is equal to or less than the limiting driving force.

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