Vehicle control system

Abstract

This design minimizes the discomfort the driver may experience due to changes in deceleration caused by the motor stopping. [Solution] The vehicle 500 includes an internal combustion engine 10 in which a GPF 41 for collecting particulate matter in the exhaust is provided in the exhaust pipe 90, and a first motor generator 310 that performs motoring to rotate the crankshaft 18 of the internal combustion engine 10. The control device 100 performs a regeneration process to regenerate the GPF 41 by performing motoring during fuel cut-off of the internal combustion engine 10. During the execution of the regeneration process, if the temperature of the GPF 41 is above a predetermined temperature when the driver of the vehicle 500 requests deceleration, the control device 100 performs a process to stop motoring and perform firing to burn the air-fuel mixture.

Description

Technical Field

[0001] The present invention relates to a vehicle control device.

Background Art

[0002] In the vehicle described in Patent Document 1, when the internal combustion engine is in a fuel cut state, the motor is used to motor the engine, so as to regenerate the filter provided in the exhaust passage.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the temperature of the filter becomes excessively high during regeneration, it is desirable to stop the motoring in order to suppress damage to the filter. However, when the motoring is stopped, the deceleration of the vehicle changes, which may give a sense of discomfort to the driver of the vehicle.

Means for Solving the Problems

[0005] The vehicle control device for solving the above problems is applied to a vehicle including an internal combustion engine provided with a filter for collecting particulate matter in exhaust in an exhaust passage and an electric motor for performing motoring to rotate the crankshaft of the internal combustion engine. The control device executes a regeneration process for regenerating the filter by performing the motoring during a fuel cut of the internal combustion engine, and when the temperature of the filter is above a predetermined temperature when an operation for requesting deceleration is performed by the driver of the vehicle during the execution of the regeneration process, the control device executes a process of stopping the motoring and performing firing for burning the air-fuel mixture.

Effects of the Invention

[0006] The control system in this vehicle can suppress the feeling of discomfort that can arise for the driver from changes in deceleration caused by motor stopping. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a vehicle in one embodiment. [Figure 2] Figure 2 is a flowchart showing the procedure of processing performed by the control device of the same embodiment. [Modes for carrying out the invention]

[0008] The following describes one embodiment of a vehicle control system. <Vehicle Configuration> As shown in Figure 1, the vehicle 500 is equipped with an internal combustion engine 10.

[0009] The internal combustion engine 10 includes a cylinder block 11, a cylinder head 12, and a head cover 13, among other things. The cylinder block 11 contains cylinders 16, which constitute the cylinders of the internal combustion engine 10. A piston 15 is disposed inside each cylinder 16.

[0010] The cylinder head 12 is provided with an intake port 30 for introducing intake air into the combustion chamber 17 of the internal combustion engine 10, and an exhaust port 70 for discharging exhaust gas from the combustion chamber 17. An intake valve 81 is provided in the intake port 30. The drive system for this intake valve 81 is provided with an intake-side variable valve timing mechanism 85, which is a variable valve timing mechanism that changes the valve timing of the intake valve 81, namely the opening and closing times.

[0011] An exhaust valve 82 is provided in the exhaust port 70. The drive system for this exhaust valve 82 is provided with an exhaust-side variable valve timing mechanism 86, which is a variable valve timing mechanism that changes the valve timing of the exhaust valve 82, namely the opening and closing times.

[0012] The internal combustion engine 10 is equipped with an in-cylinder injection type fuel injector 84 that injects fuel into the combustion chamber 17. Additionally, a spark plug 23 is provided in the cylinder head 12. A crankcase 19 is provided at the lower part of the cylinder block 11, which houses the crankshaft 18, the output shaft of the internal combustion engine 10.

[0013] An intake manifold 29 equipped with a surge tank 60 is connected upstream of the intake port 30, and an intake pipe 20 is connected upstream of the surge tank 60. The intake pipe 20, surge tank 60, intake manifold 29, and intake port 30 constitute the intake passage of the internal combustion engine 10.

[0014] The intake manifold 20 is equipped with, in order from upstream, an air cleaner 21, an air flow meter 51, a compressor wheel 24C of a supercharger 24 driven by exhaust gases discharged from the combustion chamber 17, an intercooler 27, a boost pressure sensor 54, and a throttle valve 28. An intake pressure sensor 55 is also installed in the surge tank 60. The throttle valve 28 adjusts the amount of intake air by changing its opening degree using an electric motor. The smaller the opening degree of the throttle valve 28, the less air passes through the throttle valve 28.

[0015] The air cleaner 21 filters the intake air taken into the intake manifold 20. The supercharger 24 supercharges the air in the intake manifold 20. The intercooler 27 cools the air after it has passed through the compressor wheel 24C. The throttle valve 28 regulates the amount of intake air by adjusting the valve opening.

[0016] The air flow meter 51 detects the intake air volume GA. The boost pressure sensor 54 detects the boost pressure PTC, which is the pressure in the downstream portion of the compressor wheel 24C in the intake manifold 20. The intake pressure sensor 55 detects the intake pressure PIM, which is the pressure inside the surge tank 60. The intake pressure PIM is the pressure in the intake passage downstream of the throttle valve 28.

[0017] Downstream of the exhaust port 70, an exhaust pipe 90 that constitutes an exhaust passage is connected. In the middle of the exhaust pipe 90, a housing that houses the turbine wheel 24T of the supercharger 24 is connected.

[0018] In the exhaust pipe 90, a three-way catalyst 40 is provided at a position downstream of the turbine wheel 24T. This three-way catalyst 40 oxidizes hydrocarbons (HC) and carbon monoxide (CO) contained in the exhaust gas to generate water and carbon dioxide. Further, the three-way catalyst 40 reduces nitrogen oxides (NOx) contained in the exhaust gas to generate nitrogen.

[0019] In the exhaust pipe 90, a gasoline particulate filter (hereinafter referred to as GPF) 41 is provided at a position downstream of the three-way catalyst 40. The GPF 41 is a filter that collects particulate matter (hereinafter referred to as PM) in the exhaust gas and has a three-way catalyst supported thereon.

[0020] The control device 100 includes a CPU 110, a memory 120, etc., and the CPU 110 executes a program stored in the memory 120 to perform various controls of the internal combustion engine 10.

[0021] The crankshaft 18 is mechanically connected to the carrier C of the planetary gear mechanism 300 that constitutes a power split device. The sun gear S of the planetary gear mechanism 300 is mechanically connected to the rotating shaft 310a of the first motor generator 310. The first motor generator 310 functions as a generator that generates electricity using the engine output, and also functions as a starting starter that cranks the crankshaft 18 when starting the internal combustion engine 10. This first motor generator 310 is an electric motor that performs a motoring operation to rotate the crankshaft 18.

[0022] The ring gear R of the planetary gear mechanism 300 is mechanically connected to the rotating shaft 320a of the second motor generator 320 and the drive wheel 400. The second motor generator 320 functions as an electric motor that generates driving force for the drive wheels 400, and also functions as a generator that generates electricity through regeneration when the vehicle is decelerating.

[0023] An AC voltage is applied to the terminals of the first motor generator 310 by the inverter 330. Similarly, an AC voltage is applied to the terminals of the second motor generator 320 by the inverter 340. Thus, the vehicle of this embodiment is equipped with a hybrid system comprising an internal combustion engine 10 and a motor generator as prime movers.

[0024] The control device 100 operates various controllable devices, including the throttle valve 28, fuel injector 84, spark plug 23, intake-side variable valve timing mechanism 85, and exhaust-side variable valve timing mechanism 86. The control device 100 also operates the inverter 330 to control the first motor generator 310. Furthermore, the control device 100 operates the inverter 340 to control the second motor generator 320.

[0025] The control device 100 includes a CPU 110 for arithmetic processing and a memory 120 that stores control programs and data. The control device 100 performs various control-related processes by having the CPU 110 execute the programs stored in the memory 120. Although not shown in the diagram, the control device 100 is composed of multiple control units, including a control unit for the internal combustion engine and control units for the first motor generator 310 and the second motor generator 320.

[0026] The control device 100 receives detection signals from the air flow meter 51, boost pressure sensor 54, and intake pressure sensor 55 described above. The control device 100 also receives detection signals from various other sensors. For example, the control device 100 receives a detection signal from the accelerator pedal operation amount sensor 52, which detects the accelerator pedal operation amount ACCP, which is the amount of operation of the accelerator pedal that adjusts the output of the internal combustion engine 10. The control device 100 also receives a detection signal from the throttle sensor 53, which detects the throttle opening TA, which is the opening degree of the throttle valve 28. The control device 100 also receives a detection signal from the vehicle speed sensor 56, which detects the vehicle speed SP of the vehicle 500. The control device 100 also receives a detection signal from the water temperature sensor 57, which detects the coolant temperature THW, which is the temperature of the coolant of the internal combustion engine 10. The control device 100 also receives a detection signal from the shift position sensor 58, which detects the shift position SFT. The shift position SFT is the operating position of the shift lever, which is located inside the vehicle 500 and operated by the driver of the vehicle 500. Furthermore, the control device 100 receives the detection signal from the crank angle sensor 50, which detects the rotation angle (crank angle) of the crankshaft 18 in order to calculate the engine rotation speed NE, and the detection signal from the vehicle speed sensor 56, which detects the vehicle speed SP. The control device 100 also receives the output signal Sm1 from the first rotation angle sensor 350, which detects the rotation angle of the first motor generator 310. The control device 100 also receives the output signal Sm2 from the second rotation angle sensor 360, which detects the rotation angle of the second motor generator 320.

[0027] The control device 100 calculates the engine load ratio KL based on the engine rotational speed NE and the intake air volume GA. The engine load ratio KL is a parameter that determines the amount of air filled into the combustion chamber 17, and is the ratio of the amount of air inflow per combustion cycle per cylinder to the standard amount of incoming air. The standard amount of incoming air is set variably according to the engine rotational speed NE.

[0028] The control device 100 calculates the required torque for the vehicle's operation based on the accelerator pedal input (ACCP) and vehicle speed (SP). The control device 100 then controls the required output Pe of the internal combustion engine 10 and the output torques of the first motor generator 310 and the second motor generator 320 to meet the vehicle's required torque. For example, if the required output Pe of the internal combustion engine 10 is "0", the control device 100 stops the operation of the internal combustion engine 10 and performs EV driving, using the output torque of the second motor generator 320 to drive the vehicle. If the required output Pe of the internal combustion engine 10 is greater than "0", the control device 100 operates the internal combustion engine 10 to obtain engine output and performs hybrid driving, using that engine output and the output torque of the second motor generator 320 to drive the vehicle.

[0029] The control device 100 controls the fuel injection from the fuel injector 84 and the opening degree of the throttle valve 28. In addition, if the output required by the internal combustion engine 10 is "0", the control device 100 performs a fuel cut, stopping fuel injection from the fuel injector 84.

[0030] The control device 100 controls the drive of the intake side variable valve timing mechanism 85 and the exhaust side variable valve timing mechanism 86 based on the engine rotational speed NE and the engine load ratio KL. The control device 100 switches the driving mode of the vehicle 500 based on the shift position SFT. The driving modes include, for example, the well-known D mode, the well-known S mode, and the well-known B mode. The D mode is the basic driving mode. The S mode is a driving mode that enhances the sporty driving performance of the vehicle 500 compared to the D mode. The B mode is a driving mode that increases the deceleration of the vehicle 500 compared to the D mode. Note that the selection of each driving mode may be performed by operating a switch provided inside the vehicle instead of operating the shift lever.

[0031] <Regarding the switch from motoring to firing> When the fuel cut described above is performed, the control device 100 performs the motoring described above. When fresh air is introduced into the high-temperature GPF41 by performing the motoring, the PM accumulated in the GPF41 is burned by the oxygen contained in the fresh air. This combustion of PM regenerates the GPF41.

[0032] If the temperature of the GPF41 becomes excessively high during regeneration, the control device 100 switches from motoring to firing to minimize damage to the GPF41. Firing is the operation of stopping motoring and burning the fuel-air mixture. The control device 100 performs firing by restarting fuel injection from the fuel injector 84. If the discharge of the spark plug 23 is stopped while motoring is in progress, the discharge of the spark plug 23 is restarted at the same time as the fuel injection from the fuel injector 84 is restarted.

[0033] If the motoring is stopped at this point, the deceleration of vehicle 500 will change, which may cause discomfort to the driver of vehicle 500. Therefore, the control device 100 performs the process shown in Figure 2.

[0034] Figure 2 shows the procedure for the processing that the control device 100 executes at predetermined intervals when the regeneration process of the GPF41 by the motoring described above begins. The processing shown in Figure 2 is realized by the CPU 110 executing a program stored in the memory 120 of the control device 100. In the following, the step number of each process is represented by a number preceded by "S".

[0035] In the series of processes shown in Figure 2, the control device 100 determines whether or not there is a user operation that changes the deceleration (S100). In process S100, the control device 100 determines that there is a user operation that changes the deceleration if the driver of the vehicle 500 has performed an operation to request deceleration. The above operation performed by the driver to request deceleration is, for example, the operation to select mode B as the driving mode of the vehicle 500.

[0036] In the process of S100, if it is determined that there is a user operation that changes the deceleration (S100: YES), the control device 100 determines whether the current filter temperature T is equal to or greater than a predetermined determination value Tref (S110). The filter temperature T is the temperature of the GPF41. The filter temperature T is calculated by the control device 100 based on, for example, the engine rotation speed NE and the charging efficiency η. The filter temperature T may also be detected using a sensor or the like. The charging efficiency η is a value calculated by the control device 100 based on the engine rotation speed NE and the intake air volume GA. The determination value Tref is, for example, a value obtained by multiplying the temperature at which the GPF41 is thermally damaged by a predetermined safety factor.

[0037] In the process of S110, if it is determined that the current filter temperature T is not equal to or greater than the predetermined judgment value Tref (S110: NO), the control device 100 performs the motoring described above (S120). In the process of S120, if motoring is currently being performed, the control device 100 continues motoring. In the process of S120, if firing is currently being performed, the control device 100 stops firing and performs motoring.

[0038] On the other hand, in the process of S110, if it is determined that the current filter temperature T is equal to or greater than a predetermined judgment value Tref (S110: YES), the control device 100 stops motoring and performs firing to burn the air-fuel mixture (S130). In the process of S130, if firing is currently being performed, the control device 100 continues firing. In the process of S130, if motoring is currently being performed, the control device 100 stops motoring and performs firing.

[0039] Then, if the process in S120 or the process in S130 is executed, or if a negative determination is made in the process in S100, the control device 100 terminates this process for the current cycle.

[0040] <Operation and Effects of This Embodiment> The control device 100 performs a regeneration process to regenerate the GPF 41 by performing motoring during fuel cut-off of the internal combustion engine 10. If, during the execution of the regeneration process, the driver of the vehicle 500 requests deceleration and the filter temperature T is greater than or equal to a predetermined judgment value Tref (S110: YES shown in Figure 2), the control device 100 performs the process of S130. The process of S130 is to stop motoring and perform firing to burn the air-fuel mixture. In this embodiment, the above operation to request deceleration performed by the driver is the operation in which the driver selects mode B as the driving mode of the vehicle 500.

[0041] Therefore, during the regeneration process, the motor stops in accordance with the timing at which the driver requests a feeling of deceleration. This prevents the driver from feeling uncomfortable due to the change in deceleration caused by the motor stopping.

[0042] <Example of changes> The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0043] In the S100 process, the operation performed by the driver to request deceleration was the operation to select B mode as the driving mode of vehicle 500, but other operations to request deceleration may also be performed. For example, the operation to select S mode as the driving mode of vehicle 500 may also be performed. Furthermore, if the drive system of vehicle 500 is equipped with a transmission that changes the gear ratio, the operation performed by the driver to request deceleration may also be a downshift operation performed by the driver. A downshift operation is an operation that increases the gear ratio of the transmission.

[0044] The internal combustion engine 10 does not need to be equipped with an intake-side variable valve timing mechanism 85, an exhaust-side variable valve timing mechanism 86, or a supercharger 24. • The vehicle's hybrid system is not limited to the one shown in Figure 1; other hybrid systems may also be used.

[0045] The number of motor generators equipped in the vehicle can be changed as needed. The placement position of the GPF41 in the exhaust pipe 90 can be changed as appropriate. • GPF41 may be a filter that does not support a three-way catalyst.

[0046] The control device 100 is not limited to one that includes a CPU and memory and performs software processing. For example, the control device 100 may include a dedicated hardware circuit, such as an ASIC, that performs hardware processing for at least a portion of what is processed by software in the above embodiment. That is, the control device 100 may include a processing circuit having any of the following configurations (a) to (c): (a) A processing circuit comprising one or more processing units that perform all of the above processing according to a program, and one or more program storage devices such as ROMs that store the program. (b) A processing circuit comprising one or more processing units and one or more program storage devices that perform a portion of the above processing according to a program, and one or more dedicated hardware circuits that perform the remaining processing. (c) A processing circuit comprising one or more dedicated hardware circuits that perform all of the above processing. The program storage device, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer. [Explanation of symbols]

[0047] 10...Internal combustion engine 11...Cylinder block 12...Cylinder head 13...Head cover 15...Piston 16...Cylinder 17...Combustion chamber 18...Crankshaft 19...Crankcase 20...Intake pipe 21...Air cleaner 23...Spark plug 24...Supercharger 24C...Compressor wheel 24T...Turbine wheel 27...Intercooler 28...Throttle valve 29...Intake manifold 30...Intake port 40...Thrust catalytic converter 41...Gasoline particulate filter 41...GPF 50...Crank angle sensor 51...Air flow meter 52...Accelerator pedal position sensor 53...Throttle sensor 54...Boost pressure sensor 55...Intake pressure sensor 56...Vehicle speed sensor 57...Water temperature sensor 58...Shift position sensor 60...Surge tank 70...Exhaust port 81...Intake valve 82...Exhaust valve 84…Fuel injector 85…Intake-side variable valve timing mechanism 86…Exhaust-side variable valve timing mechanism 90…Exhaust pipe 100…Control device 110…CPU 120…Memory 300…Planetary gear mechanism 310…First motor generator 310a…Rotating shaft 320…Second motor generator 320a…Rotating shaft 330…Inverter 340…Inverter 350…First rotation angle sensor 360…Second rotation angle sensor 400…Drive wheel 500…Vehicle

Claims

1. A vehicle control device comprising an internal combustion engine having a filter in the exhaust passage for collecting particulate matter in the exhaust, and an electric motor that performs motoring to rotate the crankshaft of the internal combustion engine, During the fuel cut-off of the internal combustion engine, the motoring is performed to regenerate the filter, and a regeneration process is carried out. During the regeneration process, if the temperature of the filter is above a predetermined temperature when the driver of the vehicle requests deceleration, the motoring is stopped and a firing process is performed to burn the fuel-air mixture. Vehicle control system.

2. The operation described above is the operation in which the driver selects mode B as the driving mode of the vehicle. A vehicle control device according to claim 1.

3. The aforementioned operation is a downshift operation performed by the driver. A vehicle control device according to claim 1.

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