Control system for hybrid vehicles

Abstract

To provide a control device of a hybrid vehicle which can suppress rust caused by moisture generated by combustion.SOLUTION: A control device of a hybrid vehicle, in which a processor 152 of an ECU 150 includes an internal combustion engine 10 having an oil jet 31 for supplying oil to the periphery of a piston 15, and an MG 112 for vehicle driving, includes: a fuel injection control part 152b for controlling fuel injection to the internal combustion engine 10 and stopping fuel injection before the internal combustion engine 10 is stopped; a first motoring operation part 152c1 for reducing an intake air quantity into a cylinder in a state in which the fuel injection is stopped before the internal combustion engine 10 is stopped, rotating a crank shaft 18 of the internal combustion engine 10 by drive force of the MG 112 and performing first motoring operation; and an engine stop part 152d for stopping the internal combustion engine 10 after the first motoring operation.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Conventionally, in a hybrid vehicle, during a specified period in which the engine is intermittently stopped at the start of EGR after warm-up, the engine is motored to evaporate and discharge the condensed water flowing in from the EGR system, suppressing the adhesion of condensed water that contributes to the generation of deposits in the fuel injection valve (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an internal combustion engine, since the burned gas generated by combustion contains moisture, when the burned gas passes through the gap between the piston and the cylinder, it is cooled and condensed water is generated. Therefore, when the vehicle system stops, this condensed water may adhere to the components of the internal combustion engine such as the cylinder liner, piston ring, piston wear ring, and combustion chamber wall made of iron material, and rust may occur. And when rust occurs on these components, there are concerns such as an increase in blow-by gas and a deterioration in fuel consumption due to an increase in friction. In particular, in an internal combustion engine that uses hydrogen as fuel, since the burned gas generated when hydrogen is burned contains a large amount of moisture, these rust problems may occur prominently.

[0005] However, the technology described in Patent Document 1 above assumes the discharge of condensed water when the vehicle's drive system is in operation, and does not take into account the effects of moisture when the vehicle's drive system is stopped, such as when the vehicle is parked. When the vehicle is stopped, the burnt gas inside the cylinder cools and condenses inside the cylinder, which causes rust on iron components, but the technology described in Patent Document 1 above has difficulty suppressing the occurrence of rust due to residual moisture inside the cylinder when the vehicle is stopped.

[0006] In view of the above issues, the purpose of this disclosure is to provide a control device for a hybrid vehicle that can suppress rust caused by moisture generated by combustion. [Means for solving the problem]

[0007] The gist of this disclosure is as follows:

[0008] (1) A control device for a hybrid vehicle comprising an internal combustion engine having an oil supply unit that supplies oil around a piston, and a motor for driving the vehicle, A fuel injection control unit that controls fuel injection to the internal combustion engine, comprising a fuel injection control unit that stops fuel injection before stopping the internal combustion engine, Before stopping the internal combustion engine, a first motoring operation unit reduces the amount of intake air into the cylinder with fuel injection stopped, and rotates the crankshaft of the internal combustion engine with the driving force of the motor to perform a first motoring operation. An engine stop unit for stopping the internal combustion engine after the first motoring operation, A control device for hybrid vehicles, equipped with the following features.

[0009] (2) When the internal combustion engine is stopped after performing the first motoring operation, the second motoring operation unit increases the amount of intake air into the cylinder with fuel injection stopped and rotates the crankshaft with the driving force of the motor to perform a second motoring operation when the internal combustion engine is started again, The fuel injection control unit is a control device for the hybrid vehicle described in (1) above, which starts fuel injection after the second motoring operation.

[0010] (3) The control device for the hybrid vehicle described in (1) or (2) above, wherein the first motoring operation unit performs the first motoring operation by fully closing the throttle valve.

[0011] (4) The control device for the hybrid vehicle described in (2) above, wherein the second motoring operation unit performs the second motoring operation by fully opening the throttle valve.

[0012] (5) Equipped with an SOC determination unit that determines the SOC of the battery, The control device for a hybrid vehicle according to any of (1) to (4) above, wherein the first motoring operation unit does not perform the first motoring operation if the State of Charge (SOC) of the battery is below a predetermined value.

[0013] (6) Equipped with an SOC determination unit that determines the SOC of the battery, The control device for the hybrid vehicle described in (2) or (4) above, wherein the second motoring operation unit does not perform the second motoring operation if the State of Charge (SOC) of the battery is below a predetermined value.

[0014] (7) A control device for a hybrid vehicle according to any of (1) to (6) above, wherein the internal combustion engine uses hydrogen as fuel. [Effects of the Invention]

[0015] According to this disclosure, a control device for a hybrid vehicle is provided that can suppress rust caused by moisture generated by combustion. [Brief explanation of the drawing]

[0016] [Figure 1] This diagram schematically shows the configuration of a vehicle according to one embodiment. [Figure 2]It is a schematic diagram showing the configuration of a system including an internal combustion engine and an MG. [Figure 3] It is a schematic diagram showing the functional blocks of the processor of the ECU. [Figure 4] It is a flowchart showing the processing performed by the processor of the ECU for each predetermined control cycle. [Figure 5] It is a flowchart showing the processing performed by the processor of the ECU for each predetermined control cycle. [Figure 6] It is a flowchart showing the processing performed by the processor of the ECU for each predetermined control cycle. [Figure 7] It is a flowchart showing the processing performed by the processor of the ECU for each predetermined control cycle.

Mode for Carrying Out the Invention

[0017] Hereinafter, several embodiments according to the present invention will be described with reference to the drawings. However, these descriptions are intended merely as examples of preferred embodiments of the present invention and are not intended to limit the present invention to such specific embodiments. In the following description, the same reference numerals are assigned to similar components.

[0018] FIG. 1 is a diagram schematically showing the configuration of a vehicle 200 according to one embodiment. In FIG. 1, the left side shows the front of the vehicle 200, and the right side shows the rear of the vehicle 200. As shown in FIG. 1, the vehicle 200 has an internal combustion engine 10, a motor generator (MG) 112, and a power split mechanism 116. In addition, the vehicle 200 includes a power control unit (PCU) 118 electrically connected to the MG 112 and a battery 120 electrically connected to the PCU 118.

[0019] In this embodiment, the internal combustion engine 10 is exemplified as a prime mover that uses hydrogen as fuel, burns hydrogen inside the engine, and converts the thermal energy of the combustion gas into mechanical energy. On the other hand, the fuel for the internal combustion engine 10 is not limited to hydrogen; any fuel that generates water during combustion can be used to obtain the rust-preventive effect according to this embodiment, and the occurrence of rust on iron parts will be suppressed. Therefore, biofuels, ethanol-based fuels, gasoline, diesel fuel, etc., can be used as the fuel for the internal combustion engine 10.

[0020] The internal combustion engine 10 is connected to the power split mechanism 116, and the output of the internal combustion engine 10 is used to drive the vehicle 200 or to generate electricity in the MG 112.

[0021] The MG112 functions as both an electric motor and a generator. The MG112 is connected to the power split mechanism 116 and is used to drive the vehicle 200 and to perform regenerative braking on the vehicle 200. The MG112 is also capable of driving the internal combustion engine 10 for motoring operation. In this embodiment, the MG112, which has a power generation function, is used as the motor to drive the vehicle 200, but a motor without a power generation function may also be used.

[0022] The PCU118 is connected between the battery 120 and the MG112 and controls the power supplied to the MG112. The PCU118 includes components such as an inverter to drive the motor, a boost converter to control the voltage, and a DC-DC converter to step down the high voltage. The battery 120 is connected to the PCU118 and the MG112 and supplies power to the MG112 to drive the vehicle 200.

[0023] As described above, the vehicle 200 is configured as a hybrid vehicle equipped with a hydrogen-fueled internal combustion engine 10 and an MG 112. However, the vehicle 200 may be any type of vehicle as long as it is equipped with an internal combustion engine 10 and an MG (or motor) 112, and the MG 112 is capable of driving the internal combustion engine 10. For example, the vehicle 200 may be configured such that the internal combustion engine 10 is used only for power generation and only the motor drives the vehicle 200. Alternatively, the vehicle 200 may be configured to have two MGs, one mainly used for driving the vehicle 200 and another mainly used for power generation.

[0024] Figure 2 is a schematic diagram showing the configuration of a system 100 including an internal combustion engine 10 and an MG112. As shown in Figure 2, the internal combustion engine 10 comprises a cylinder block 11, a cylinder head 12, a head cover 13, and an oil pan 14. A piston 15 is reciprocally mounted inside a cylinder 16 of the cylinder block 11. The piston 15 is provided with multiple piston rings. The combustion chamber 17 is formed by the space enclosed by the wall surface of the cylinder 16, the crown surface of the piston 15, and the cylinder head 12. The head cover 13 is provided with a filler cap for injecting oil, etc.

[0025] The cylinder head 12 is rotatably equipped with an intake camshaft (not shown) that drives the intake valves to open and close, and an exhaust camshaft (not shown) that drives the exhaust valves to open and close. The cylinder head 12 is also equipped with fuel injection valves (not shown).

[0026] A crankcase 19 is provided at the lower part of the cylinder block 11, which rotatably supports the crankshaft 18. Below this crankcase 19, an oil pan 14 for storing lubricating oil is assembled.

[0027] An intake manifold 29 equipped with a surge tank 60 is connected to the cylinder head 12, and an intake pipe 20 with various devices installed is connected upstream of the surge tank 60. The intake pipe 20, surge tank 60, and intake manifold 29 constitute the intake passage of the internal combustion engine 10. An exhaust manifold 30 is also connected to the cylinder head 12. An exhaust pipe (not shown) equipped with an exhaust catalytic converter is connected downstream of the exhaust manifold 30.

[0028] The intake manifold 20 is equipped with, in order from upstream, an air cleaner 21, an air flow meter 91, a compressor 24C of a supercharger 24 driven by exhaust gases from the combustion chamber 17, an intercooler 27, a pressure sensor 93, and an electrically operated throttle valve 28.

[0029] The air cleaner 21 filters the intake air taken into the intake manifold 20, and the supercharger 24 pressurizes (supercharges) the air taken into the intake manifold 20. In addition, the intercooler 27 cools the air after it has passed through the compressor 24C, and the intake air volume is adjusted by adjusting the opening of the throttle valve 28.

[0030] The internal combustion engine 10 is equipped with an oil jet 31. The oil jet 31 is one form of an oil supply unit that supplies oil around the piston 15. The oil jet 31 is attached to the lower end of the cylinder block 11. The oil jet 31 is connected to a pump (not shown) that is driven by the rotation of the internal combustion engine 10. When the pump is driven, oil flows into the oil jet 31. The oil that flows into the oil jet 31 is sprayed from the nozzle 31a of the oil jet 31 toward the bottom dead center side of the piston 15. The oil supply unit may also be configured in a way that the crankshaft 18 scrapes up the oil in the oil pan 14.

[0031] The ECU 150 is one embodiment of a control device for a hybrid vehicle, and controls a system 100 including an internal combustion engine 10 and an MG 112. It performs various controls on the system 100 by operating various target devices such as a throttle valve 28, a fuel injector, and the MG 112. The ECU 150 has a processor 152, a memory 154, and a communication interface 156. The processor 152 has one or more CPUs (Central Processing Units) and their peripheral circuits. The processor 152 may further have other arithmetic circuits such as a logic unit, a numerical unit, or a graphics processing unit. The memory 154 has, for example, a volatile semiconductor memory and a non-volatile semiconductor memory, and stores data related to the processing according to this embodiment as needed. The communication interface 156 has an interface circuit for connecting the ECU 150 to an in-vehicle network.

[0032] When performing various controls on the internal combustion engine 10, the ECU 150 refers to the intake air volume detected by the air flow meter 91, the engine rotation speed calculated from the output signal of the crank angle sensor 92, and the terminal current and terminal voltage of the battery 120 detected by the battery sensor 96. Furthermore, when performing various controls on the internal combustion engine 10, the ECU 150 refers to the intake pressure detected by the pressure sensor 93, the output signal of the accelerator pedal position sensor 94 which detects the amount of accelerator pedal operation (accelerator opening), and the vehicle speed of the vehicle 200 detected by the vehicle speed sensor 95. Additionally, when performing various controls on the MG 112, the ECU 150 refers to the terminal current and terminal voltage of the battery 120 detected by the battery sensor 96.

[0033] The throttle valve 28, ignition switch 97, various devices such as the fuel injector or MG112, and the various sensors provided by the system 100 are connected to the ECU 150 via an in-vehicle network compliant with standards such as the Controller Area Network (CAN).

[0034] The internal combustion engine 10, which burns hydrogen, primarily produces water during the combustion of hydrogen. As a result, moisture is present inside the cylinder 16. This moisture can adhere to the cylinder liner, piston rings, and piston wear rings, which are made of iron, potentially causing rust on these components when the system 100 is stopped. Consequently, as mentioned above, there are concerns about increased blow-by gas and decreased fuel efficiency due to increased friction.

[0035] In this embodiment, when the vehicle driver turns off the ignition switch 97 to stop the system 100, fuel injection is cut off for a predetermined time before the system stops, and with the throttle valve 28 fully closed, the crankshaft 18 is rotated by the MG 112. This causes moisture in the cylinder to be scavenged and discharged through the exhaust manifold 30 and exhaust pipe. Furthermore, by fully closing the throttle valve 28, negative pressure is generated in the combustion chamber 17, causing oil to flow into the combustion chamber 17 from the gap between the cylinder 16 and the piston 15. Oil is supplied to the piston 15, cylinder 16, or combustion chamber 17 and the surrounding parts, and these parts are covered with an oil film. Therefore, the occurrence of rust caused by moisture generated by the combustion of hydrogen is suppressed, and rust prevention can be achieved. In this specification, the rotation of the crankshaft 18 by the MG 112 is referred to as motoring.

[0036] On the other hand, if rust prevention measures are taken before shutting down the system, when the system 100 is started and the internal combustion engine 10 is operated, the oil supplied to the piston 15, cylinder 16, or combustion chamber 17 and its surrounding parts may burn, generating oil-derived particulate matter (PM), which could increase the number of particulate matter particles (PN) emitted from the internal combustion engine 10. For this reason, when the system is started, fuel injection is stopped and the throttle valve 28 is fully open for a predetermined period of time during motoring operation. This allows air to pass through the gap between the cylinder 16 and the piston 15 and flow into the crankcase 19. Consequently, the oil supplied to the piston 15, cylinder 16, or combustion chamber 17 and its surrounding parts is returned to the crankcase 19 along with the air passing through the gap between the cylinder 16 and the piston 15.

[0037] Figure 3 is a schematic diagram showing the functional blocks of the processor 152 of the ECU 150 for realizing the above-described processing. The processor 152 of the ECU 150 includes a system request determination unit 152a, a fuel injection control unit 152b, a motoring operation unit 152c, an engine stop unit 152d, and a SOC determination unit 152e. Each of these parts of the processor 152 is a functional module realized, for example, by a computer program running on the processor 152. In other words, the functional blocks of the processor 152 consist of the processor 152 and a program (software) to make it function. The program may also be recorded in the memory 154 of the ECU 150 or on an externally connected recording medium. Alternatively, each of these parts of the processor 152 may be a dedicated arithmetic circuit provided in the processor 152.

[0038] The system request determination unit 152a of the processor 152 determines whether a stop request or a start request for the system 100 has been issued. For example, the system request determination unit 152a determines that a stop request for the system 100 has been issued when the ignition switch 97 is turned off. Also, the system request determination unit 152a determines that a start request for the system 100 has been issued when the ignition switch 97 is turned on.

[0039] The fuel injection control unit 152b of the processor 152 stops fuel injection before stopping the internal combustion engine 10. Furthermore, if the internal combustion engine 10 is stopped by performing the first motoring operation described later, the fuel injection control unit 152b will start fuel injection after the second motoring operation described later when starting the internal combustion engine 10 again.

[0040] The motoring operation unit 152c of the processor 152 has a first motoring operation unit 152c1 and a second motoring operation unit 152c2. Before stopping the internal combustion engine 10, the first motoring operation unit 152c1 reduces the amount of intake air into the cylinder with fuel injection stopped and rotates the crankshaft 18 with the driving force of the MG 112 to perform a first motoring operation (rust prevention operation). The first motoring operation unit 152c1 reduces the amount of intake air into the cylinder, for example, by completely closing the throttle valve 28.

[0041] During the first motoring operation, fuel injection is stopped, so no new moisture is generated by combustion. In addition, by performing the first motoring operation, air flows from the intake manifold 29 to the exhaust manifold 30, which scavenges any moisture remaining inside the combustion chamber 17 and discharges it to the outside through the exhaust pipe. Therefore, a rust prevention effect is obtained by removing moisture.

[0042] Furthermore, since the first motoring operation is performed without generating explosion pressure in the combustion chamber 17, oil is drawn in by the negative pressure inside the cylinder during the intake stroke, and flows into the combustion chamber 17 through the gap between the piston 15 and the cylinder 16, covering the piston 15, cylinder 16, or combustion chamber 17 and the surrounding parts with an oil film. Also, since the amount of intake air into the cylinder is reduced at this time, negative pressure inside the cylinder is effectively generated, and the oil is reliably drawn in. As a result, the oil reaches all of these parts, and contact with moisture is suppressed, so a more reliable rust prevention effect is obtained. Therefore, the occurrence of rust on these parts is suppressed.

[0043] The rust-preventive effect of the first motoring operation can be obtained both before and after the internal combustion engine 10 has warmed up. Furthermore, in the case of an internal combustion engine 10 that uses hydrogen as fuel, as in this embodiment, the burnt gas contains a large amount of moisture, but the occurrence of rust on iron components is reliably suppressed by performing the first motoring operation.

[0044] The first motoring unit 152c1 may perform a first motoring operation until the parts requiring rust prevention are covered with an oil film. For example, the first motoring unit 152c1 may perform a first motoring operation until the area around the piston ring (including the sliding surface between the piston ring and the inner wall of the cylinder 16, and the land portion between the upper and lower piston rings) is covered with an oil film of sufficient thickness to obtain the desired rust prevention effect. Performing the first motoring operation increases the thickness of the oil film around the piston ring compared to when the first motoring operation is not performed. Specifically, when the first motoring operation is not performed, the oil film thickness on the sliding surface between the piston ring and the inner wall of the cylinder 16 is about a few μm, and the oil film thickness on the land portion between the upper and lower piston rings is about 10 μm, but performing the first motoring operation increases the thickness of these oil films by about 1.5 to 10 times. Generally, a thicker oil film is more effective at preventing rust. However, once a certain thickness of oil film is formed, further increases in thickness do not significantly alter the rust-preventive effect. Therefore, the duration of the first motoring operation is determined by considering the thickness of the oil film and the motoring time, ensuring that the motoring time is not excessively long while still providing sufficient rust prevention. The time required for the area around the piston rings to be covered with an oil film of sufficient thickness to achieve the desired rust prevention effect can be determined experimentally, but one example is approximately 200 cycles.

[0045] Furthermore, the higher the rotational speed during the first motoring operation, the thicker the oil film becomes. Therefore, increasing the rotational speed during the first motoring operation allows for a shorter duration of the first motoring operation.

[0046] When the internal combustion engine 10 is stopped after the first motoring operation, the second motoring operation unit 152c2 increases the amount of intake air into the cylinder with fuel injection stopped and rotates the crankshaft 18 with the driving force of the MG 112 to perform the second motoring operation when starting the internal combustion engine 10 again. The second motoring operation unit 152c2 increases the amount of intake air into the cylinder, for example, by fully opening the throttle valve 28.

[0047] During the second motoring operation, the amount of intake air into the cylinder is increased, so when the piston 15 rises during the compression stroke, the air in the combustion chamber 17 is compressed at a higher cylinder pressure. As a result, the high-pressure compressed air flows into the crankcase 19 through the gap between the piston 15 and the cylinder 16. This causes the oil that was covering the combustion chamber 17 and the area around the piston rings to be returned to the crankcase 19 along with the compressed air. Therefore, when fuel injection is started after the second motoring operation, the combustion of oil covering the piston 15, cylinder 16, or combustion chamber 17 and the surrounding parts, which generates PM, is suppressed, and the increase in PN is suppressed. Thus, the deterioration of emissions due to oil combustion is reliably suppressed.

[0048] The second motoring operation is performed until the oil covering the piston 15, cylinder 16, or combustion chamber 17 and the surrounding parts is removed (or until the thickness of the oil film is below a predetermined value). For example, the second motoring unit 152c2 may perform the second motoring operation until the oil film is removed from the piston rings (or until the thickness of the oil film is below a predetermined value). The duration of the second motoring operation can be determined experimentally, but as an example, it may be around 200 cycles.

[0049] The first motoring unit 152c1 does not perform the first motoring operation if the charge state (SOC: State of Charge) of the battery 120 is below a predetermined value. Similarly, the second motoring unit 152c2 does not perform the second motoring operation if the SOC of the battery 120 is below a predetermined value. This suppresses power consumption due to motoring and prevents further decrease in SOC, thereby preventing starting problems of the internal combustion engine 10 due to depletion of power.

[0050] The engine stop unit 152d of the processor 152 stops the internal combustion engine 10 after the first motoring operation. Specifically, the engine stop unit 152d stops the internal combustion engine 10 by turning off the driving force of the MG 112.

[0051] The SOC determination unit 152e of the processor 152 determines the State of Charge (SOC) of the battery 120 based on the terminal current and terminal voltage of the battery 120 detected by the battery sensor 96 when motoring operation is performed during system shutdown or startup. The SOC determination unit 152e determines whether the SOC of the battery 120 is above a predetermined value.

[0052] The following describes the processes performed by the processor 152 of the ECU 150, based on the flowcharts in Figures 4 to 7. Figures 4 to 7 are flowcharts showing the processes performed by the processor 152 of the ECU 150 at predetermined control cycles.

[0053] Figure 4 is a flowchart showing the process when the system stops. First, the system request determination unit 152a of the processor 152 determines whether or not a system stop request has been issued for the system 100 (step S10). The system request determination unit 152a determines that a system stop request has been issued when the vehicle driver turns off the ignition switch 97.

[0054] If it is determined in step S10 that a system shutdown request has been issued, the processor 152 determines whether the internal combustion engine 10 was operating while the system 100 was running (while the vehicle 200 was tripped) before the shutdown request was issued (step S12). On the other hand, if it is determined in step S10 that no system shutdown request has been issued, the processing for this control cycle ends.

[0055] If it is determined in step S12 that the internal combustion engine 10 was operating, the fuel injection control unit 152b of the processor 152 stops fuel injection (step S13). On the other hand, if it is determined in step S12 that the internal combustion engine 10 was not operating, no water is generated by the combustion of hydrogen, and rust prevention is unnecessary, so the processing in this control cycle ends.

[0056] Next, the first motoring operation unit 152c1 of the processor 152 closes the throttle valve 28 completely (step S14) and rotates the crankshaft 18 with the driving force of the MG 112 to perform the first motoring operation (step S16). Next, the engine stop unit 152d of the processor 152 stops the internal combustion engine 10 after the first motoring operation (step S18). After step S18, the processing for this control cycle is completed.

[0057] Figure 5 is a flowchart showing the process during system startup. First, the system request determination unit 152a of the processor 152 determines whether or not a system startup request has been issued for the system 100 (step S20). The system request determination unit 152a determines that a system startup request has been issued when the vehicle driver turns on the ignition switch 97.

[0058] If it is determined in step S20 that a system start request has been issued, the processor 152 determines whether or not the first motoring operation (rust prevention operation) was performed during the previous system shutdown (step S22). On the other hand, if it is determined in step S20 that no system start request has been issued, the processing for this control cycle ends.

[0059] If it is determined in step S22 that the first motoring operation was performed when the system was shut down last time, the second motoring operation unit 152c2 of the processor 152 fully opens the throttle valve 28 (step S24) and rotates the crankshaft 18 with the driving force of the MG 112 to perform the second motoring operation (step S26). On the other hand, if it is determined in step S22 that the first motoring operation was not performed, the processing for this control cycle ends.

[0060] Next, the fuel injection control unit 152b of the processor 152 starts fuel injection after the second motoring operation (step S28). After step S28, processing in this control cycle ends.

[0061] Figure 6 is a flowchart showing the process in Figure 4 where the first motoring operation is performed if the State of Charge (SOC) of the battery 120 is equal to or greater than a predetermined value X. In this case, if it is determined in step S12 that the internal combustion engine 10 was operating, the SOC determination unit 152e of the processor 152 determines whether or not the SOC of the battery 120 is equal to or greater than a predetermined value X (step S19). If the SOC of the battery 120 is equal to or greater than the predetermined value X in step S19, the processes from step S13 onwards are performed. On the other hand, if the SOC of the battery 120 is less than the predetermined value X in step S19, the processes from step S13 onwards are not performed. Note that in Figure 6, processes other than step S19 are performed in the same way as in Figure 4.

[0062] Figure 7 is a flowchart showing the process in Figure 5 where a second motoring operation is performed if the State of Charge (SOC) of the battery 120 is greater than or equal to a predetermined value X. In this case, if it is determined in step S22 that a first motoring operation was performed when the system was shut down previously, the SOC determination unit 152e of the processor 152 determines whether or not the SOC of the battery 120 is greater than or equal to a predetermined value X (step S29). If the SOC of the battery 120 is greater than or equal to the predetermined value X in step S29, the processes from step S24 onwards are performed. On the other hand, if the SOC of the battery 120 is less than the predetermined value X in step S29, the processes from step S24 onwards are not performed. Note that in Figure 7, processes other than step S29 are performed in the same way as in Figure 5.

[0063] As described above, according to this embodiment, before stopping the internal combustion engine 10, the amount of intake air into the cylinder is reduced with fuel injection stopped, and the crankshaft 18 is rotated by the driving force of the MG 112 to perform a first motoring operation. As a result, any moisture remaining inside the combustion chamber 17 is scavenged, and the negative pressure generated in the intake manifold 29 and combustion chamber 17 covers the piston 15, cylinder 16, or combustion chamber 17 and the surrounding parts with an oil film. Therefore, rust on these parts is suppressed.

[0064] Furthermore, when the internal combustion engine 10 is stopped after the first motoring operation, the second motoring operation is performed when the internal combustion engine 10 is started again, with fuel injection stopped and the amount of intake air into the cylinder increased, by rotating the crankshaft 18 with the driving force of the MG 112. As a result, the oil that was covering the combustion chamber 17 and the area around the piston rings is returned to the crankcase 19, so the combustion of oil covering the piston 15, cylinder 16, or combustion chamber 17 and the surrounding parts, which generates PM, is suppressed, and the increase in PN is suppressed. [Explanation of symbols]

[0065] 10 Internal combustion engine 15 pistons 16 cylinders 17 Combustion chamber 18 Crankshaft 28 Throttle valve 31 Oil Jet 96 Battery Sensor 97 Ignition Switch 100 Systems 112 Motor Generator (MG) 152 processors 152a System Request Determination Unit 152b Fuel injection control unit 152c Motoring Operation Unit 152c1 First motoring unit 152c2 Second motoring unit 152d Engine Stop Section 152e SOC judgment section 200 vehicles

Claims

1. A control device for a hybrid vehicle comprising an internal combustion engine that uses hydrogen as fuel and a motor for driving the vehicle, having an oil supply unit that supplies oil around the piston, A fuel injection control unit that controls fuel injection to the internal combustion engine, comprising a fuel injection control unit that stops fuel injection before stopping the internal combustion engine, Before stopping the internal combustion engine, a first motoring operation unit reduces the amount of intake air into the cylinder with fuel injection stopped, and rotates the crankshaft of the internal combustion engine with the driving force of the motor to perform a first motoring operation. An engine stop unit for stopping the internal combustion engine after the first motoring operation, When the internal combustion engine is stopped after the first motoring operation described above, the system includes a second motoring operation unit that, when starting the internal combustion engine again, increases the amount of intake air into the cylinder with fuel injection stopped and rotates the crankshaft with the driving force of the motor to perform a second motoring operation, The fuel injection control unit starts fuel injection after the second motoring operation. The second motoring operation unit is a control device for a hybrid vehicle that, if the internal combustion engine is stopped without performing the first motoring operation, does not perform the second motoring operation when starting the internal combustion engine for the next time.

2. The control device for a hybrid vehicle according to claim 1, wherein the first motoring operation unit performs the first motoring operation by fully closing the throttle valve.

3. The control device for a hybrid vehicle according to claim 1, wherein the second motoring operation unit performs the second motoring operation by fully opening the throttle valve.

4. It includes an SOC determination unit that determines the battery's SOC, The control device for a hybrid vehicle according to any one of claims 1 to 3, wherein the first motoring operation unit does not perform the first motoring operation if the battery's SOC is below a predetermined value.

5. It includes an SOC determination unit that determines the battery's SOC, The control device for a hybrid vehicle according to claim 1 or 3, wherein the second motoring operation unit does not perform the second motoring operation if the SOC of the battery is below a predetermined value.

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