Vehicle control device

Abstract

To suppress occurrence of backfire in an internal combustion engine.SOLUTION: A vehicle includes an internal combustion engine, a motor generator, a cooling water pump, and a cooling water circulation passage. The internal combustion engine uses hydrogen as fuel and functions as a driving source of the vehicle. The motor generator functions as a driving source of the vehicle. The cooling water pump is an electric pump for pressure-feeding the cooling water to the internal combustion engine. In the cooling water circulation passage, the cooling water is circulated between the internal combustion engine and the cooling water pump. The control device for the vehicle executes acquisition processing for acquiring an intake system temperature that is a temperature of an intake passage of the internal combustion engine. On the condition that the intake system temperature is a predetermined specific temperature or higher, the control device executes EV traveling processing for stopping the internal combustion engine and traveling the vehicle by using driving force of the motor generator. On the condition that the intake system temperature is the specific temperature or higher, the control device executes pump processing for driving the cooling water pump regardless of whether or not the internal combustion engine is being driven.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] The vehicle of Patent Document 1 includes an internal combustion engine that uses hydrogen as fuel. The internal combustion engine includes a cylinder, an intake passage, an exhaust passage, a fuel injection valve, and a water injection valve. The cylinder is a space for burning a mixture of fuel and intake air. The intake passage introduces intake air from the outside of the internal combustion engine into the cylinder. The exhaust passage discharges exhaust gas from the cylinder to the outside of the internal combustion engine. The fuel injection valve supplies fuel to the cylinder via the intake passage by injecting hydrogen as fuel into the intake passage. The water injection valve injects water into the intake passage. When the injected water evaporates, the intake passage is cooled. As a result, a phenomenon in which a mixture of fuel and intake air burns in the intake passage, known as backfire, is suppressed.

[0003] The vehicle in Patent Document 1 is equipped with a control device that controls an internal combustion engine. The control device determines whether or not a backfire occurs while the internal combustion engine is running. If a backfire occurs, the control device injects water into the intake passage from the water injection valve. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-118109 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the vehicle of Patent Document 1, the temperature of the internal combustion engine is high even when the internal combustion engine is stopped, for example, immediately after the internal combustion engine is stopped. However, when the internal combustion engine is stopped, the injection of hydrogen from the fuel injection valve and the injection of water from the water injection valve are stopped. In other words, while the internal combustion engine is stopped, the internal combustion engine cannot be cooled by water from the water injection valve. Therefore, if the internal combustion engine is started again while the temperature of the internal combustion engine is high, there is a possibility that a backfire will occur immediately after the internal combustion engine is started. [Means for solving the problem]

[0006] A vehicle control device for solving the above problem is a control device for controlling a vehicle that uses hydrogen as fuel and has an internal combustion engine that functions as a power source, a motor generator that functions as a power source, an electric refrigerant pump that pressure-feeds refrigerant to the internal combustion engine, and a refrigerant circulation passage for circulating the refrigerant between the internal combustion engine and the refrigerant pump, and is capable of executing an acquisition process for acquiring an intake system temperature, which is the temperature of the intake passage of the internal combustion engine, an EV driving process for stopping the internal combustion engine and driving the vehicle using the driving force of the motor generator, on condition that the intake system temperature is above a predetermined specified temperature, and a pump process for driving the refrigerant pump regardless of whether the internal combustion engine is being driven or not, on condition that the intake system temperature is above the specified temperature.

[0007] According to the above configuration, the vehicle is driven with the internal combustion engine stopped, provided that the intake system temperature is equal to or higher than a specified temperature. In this case, the internal combustion engine is not driven as the vehicle is driven, so that the temperature of the internal combustion engine is prevented from increasing further due to the combustion of the mixture of fuel and intake air. Then, the coolant pump is driven while the internal combustion engine is stopped, so that the temperature of the internal combustion engine is reduced by heat exchange with the coolant circulating in the coolant circulation passage. As a result, even if the internal combustion engine is driven as the vehicle is driven, backfire can be prevented from occurring in the internal combustion engine. [Brief description of the drawings]

[0008] [Figure 1]FIG. 1 is a schematic configuration diagram of a vehicle. [Diagram 2] 1 is a schematic diagram of an internal combustion engine. [Diagram 3] 4 is a flowchart showing pump control. [Figure 4] 4 is a flowchart showing a driving switching control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Vehicle Overview> Hereinafter, one embodiment of the present invention will be described with reference to Figures 1 to 4. First, a schematic configuration of a vehicle 100 will be described.

[0010] As shown in Fig. 1, the vehicle 100 includes an internal combustion engine 10 and a motor generator 30. The internal combustion engine 10 functions as a drive source for the vehicle 100. The internal combustion engine 10 is an internal combustion engine that uses hydrogen as fuel. The motor generator 30 functions as a drive source for the vehicle 100. Therefore, the vehicle 100 is a so-called hybrid vehicle.

[0011] As shown in Fig. 2, the internal combustion engine 10 includes a plurality of cylinders 11, an intake passage 12, and an exhaust passage 13. The internal combustion engine 10 also includes a plurality of pistons 16, a plurality of connecting rods 17, a crankshaft 18, a plurality of intake valves 21, and a plurality of exhaust valves 22. The cylinders 11 are spaces for burning a mixture of fuel and intake air. In this embodiment, the internal combustion engine 10 includes four cylinders 11. Note that Fig. 2 shows only one cylinder 11 as a representative example.

[0012] The piston 16 is located inside the cylinder 11. The piston 16 is connected to a crankshaft 18 via a connecting rod 17. The piston 16 reciprocates inside the cylinder 11 as a mixture of fuel and intake air is burned in the cylinder 11. The reciprocating motion of the piston 16 causes the crankshaft 18 to rotate.

[0013] The intake passage 12 is connected to the cylinders 11. The intake passage 12 introduces intake air from outside the internal combustion engine 10 to each cylinder 11. The exhaust passage 13 is connected to the cylinders 11. The exhaust passage 13 discharges exhaust gas from each cylinder 11 to outside the internal combustion engine 10. The intake valve 21 is located at the downstream end of the intake passage 12. The intake valve 21 opens and closes the downstream end of the intake passage 12 by a driving force from a valve mechanism (not shown). The exhaust valve 22 is located at the upstream end of the exhaust passage 13. The exhaust valve 22 opens and closes the upstream end of the exhaust passage 13 by a driving force from a valve mechanism (not shown).

[0014] The internal combustion engine 10 includes a throttle valve 23, a plurality of ignition devices 24, a plurality of port injection valves 26, a plurality of in-cylinder injection valves 27, and a plurality of water injection valves 29. The throttle valve 23 is located midway through the intake passage 12. The throttle valve 23 adjusts the amount of intake air flowing through the intake passage 12.

[0015] The tip of the port injection valve 26 is located in the intake passage 12 near the cylinder 11. The port injection valve 26 supplies fuel into the cylinder 11 via the intake passage 12 by injecting hydrogen as fuel into the intake passage 12. The internal combustion engine 10 is provided with four port injection valves 26 corresponding to the four cylinders 11.

[0016] A tip of the in-cylinder injection valve 27 is located inside the cylinder 11. The in-cylinder injection valve 27 supplies fuel to the cylinder 11 by injecting hydrogen as fuel into the cylinder 11. The internal combustion engine 10 includes four in-cylinder injection valves 27 corresponding to the four cylinders 11.

[0017] The tip of the ignition device 24 is located inside the cylinder 11. The ignition device 24 ignites a mixture of fuel and intake air by spark discharge. The internal combustion engine 10 is provided with four ignition devices 24 corresponding to the four cylinders 11.

[0018] The tip of the water injector 29 is located in the intake passage 12 near the cylinder 11. Water is supplied to the water injector 29 from a water tank (not shown). The water injector 29 injects water into the intake passage 12. When the injected water evaporates, the intake passage 12 is cooled, and the intake air introduced from the intake passage 12 to the cylinder 11 is thereby cooled. The internal combustion engine 10 has four water injectors 29 corresponding to the four cylinders 11.

[0019] The internal combustion engine 10 includes a water jacket 15. The water jacket 15 is a space for circulating cooling water. The water jacket 15 surrounds the cylinders 11. Cooling water circulates within the water jacket 15. The cylinders 11 are cooled by heat exchange with the cooling water within the water jacket 15. The water jacket 15 constitutes a part of a cooling water circulation passage 66, which will be described later.

[0020] As shown in FIG. 1, the vehicle 100 includes a power transmission device 40, a differential 51, and a plurality of drive wheels 52. The power transmission device 40 includes a case 41, a damper 42, a connecting shaft 43, a clutch 44, a torque converter 45, and an automatic transmission 46. The case 41 accommodates the motor generator 30, the damper 42, the connecting shaft 43, the clutch 44, the torque converter 45, and the automatic transmission 46. The motor generator 30 includes a rotor 31 and a stator 32. The stator 32 is fixed to the case 41. The rotor 31 is rotatable relative to the stator 32.

[0021] A first end of the connecting shaft 43 is connected to the crankshaft 18 of the internal combustion engine 10 via a damper 42. The damper 42 transmits the driving force from the crankshaft 18 to the connecting shaft 43 while suppressing fluctuations in the torque of the crankshaft 18. A second end of the connecting shaft 43 is connected to the rotor 31 of the motor generator 30 via a clutch 44. The connection state of the clutch 44 is switched between an engaged state and a released state depending on the pressure of the oil supplied to the clutch 44.

[0022] The torque converter 45 includes a pump wheel 45A, a turbine wheel 45B, and a lock-up clutch 45C. The pump wheel 45A is connected to the rotor 31 of the motor generator 30. Therefore, the pump wheel 45A rotates as the rotor 31 rotates. When the pump wheel 45A rotates, a driving force is transmitted to the turbine wheel 45B via a fluid, and the turbine wheel 45B rotates. The turbine wheel 45B is connected to the automatic transmission 46. The lock-up clutch 45C connects the rotor 31 of the motor generator 30 to the automatic transmission 46 while bypassing the pump wheel 45A and the turbine wheel 45B. The connection state of the lock-up clutch 45C is switched between an engaged state and a released state according to the pressure of the oil supplied to the lock-up clutch 45C.

[0023] The automatic transmission 46 includes an input shaft 46A and an output shaft 46B. The input shaft 46A is connected to a turbine wheel 45B of the torque converter 45. The input shaft 46A is also connected to a lock-up clutch 45C of the torque converter 45. Therefore, in the automatic transmission 46, the driving force is transmitted from the turbine wheel 45B and the lock-up clutch 45C in the torque converter 45 to the input shaft 46A. The input shaft 46A is connected to the output shaft 46B via a clutch and a gear (not shown). The automatic transmission 46 can change the gear ratio. Here, the gear ratio is a ratio indicating the number of times the input shaft 46A rotates when the output shaft 46B rotates once. Therefore, the higher the gear ratio, the higher the speed at which the input shaft 46A rotates relative to the output shaft 46B. An example of the automatic transmission 46 is a stepped automatic transmission. The output shaft 46B is connected to the drive wheels 52 via a differential 51. The differential 51 allows a difference in rotational speed to occur between the left and right drive wheels 52 .

[0024] As shown in Fig. 1, vehicle 100 includes a hydraulic device 55. Hydraulic device 55 controls the gear ratio of automatic transmission 46 by adjusting the pressure of oil supplied to automatic transmission 46. Hydraulic device 55 also controls the engagement state of lock-up clutch 45C of torque converter 45 by adjusting the pressure of oil supplied to torque converter 45. Hydraulic device 55 also controls the engagement state of clutch 44 by adjusting the pressure of oil supplied to clutch 44.

[0025] 1, the vehicle 100 includes an inverter 56 and a battery 57. The battery 57 is a secondary battery. The inverter 56 adjusts the amount of electric power exchanged between the motor generator 30 and the battery 57.

[0026] <Circulation device peripheral configuration> As shown in FIG. 1, the vehicle 100 includes a cooling water circulation system 60, an oil circulation system 70, and a heat exchanger 75.

[0027] The cooling water circulation device 60 includes a cooling water pump 61, a thermostat 62, a radiator 63, a cooling water circulation passage 66, and a bypass passage 68. The cooling water pump 61 pumps the cooling water drawn in through an intake port from a discharge port. The cooling water pump 61 is a so-called electric pump driven by an electric motor. The cooling water pump 61 is driven by power supplied from a battery (not shown).

[0028] An upstream end of the cooling water circulation passage 66 is connected to the discharge port of the cooling water pump 61. A downstream end of the cooling water circulation passage 66 is connected to the suction port of the cooling water pump 61. In other words, the cooling water circulation passage 66 is a ring-shaped flow path that extends from the cooling water pump 61 and returns to the cooling water pump 61 again.

[0029] The radiator 63 is located downstream of the cooling water circulation passage 66 as viewed from the cooling water pump 61. The cooling water passage in the radiator 63 constitutes a part of the cooling water circulation passage 66. The radiator 63 cools the cooling water flowing through the radiator 63 by heat exchange with the air. The water jacket 15 of the internal combustion engine 10 is located downstream of the cooling water circulation passage 66 as viewed from the radiator 63 and upstream of the cooling water pump 61.

[0030] The upstream end of the bypass passage 68 is connected to a portion of the cooling water circulation passage 66 that is downstream when viewed from the cooling water pump 61 and upstream when viewed from the radiator 63. The downstream end of the bypass passage 68 is connected to a portion of the cooling water circulation passage 66 that is downstream when viewed from the radiator 63 and upstream when viewed from the water jacket 15.

[0031] The thermostat 62 is located at the connection between the upstream end of the bypass passage 68 and the cooling water circulation passage 66. The thermostat 62 switches the flow of the cooling water by opening and closing according to the temperature of the cooling water. Specifically, when the temperature of the cooling water discharged by the cooling water pump 61 is lower than a predetermined temperature A, the thermostat 62 opens the bypass passage 68 side and closes the passage on the radiator 63 side in the cooling water circulation passage 66. As a result, the cooling water that has reached the thermostat 62 flows through the bypass passage 68. That is, when the temperature of the cooling water discharged by the cooling water pump 61 is lower than the predetermined temperature A, the cooling water circulates without passing through the radiator 63. On the other hand, when the temperature of the cooling water discharged by the cooling water pump 61 is equal to or higher than the predetermined temperature A, the thermostat 62 closes the bypass passage 68 side and opens the passage on the radiator 63 side in the cooling water circulation passage 66. As a result, the cooling water that has reached the thermostat 62 flows toward the radiator 63. That is, when the temperature of the cooling water discharged by the cooling water pump 61 is equal to or higher than a predetermined temperature A, the cooling water circulates through the radiator 63. An example of the predetermined temperature A is several tens of degrees Celsius.

[0032] In this embodiment, the cooling water pump 61 is an electric cooling water pump that pressure-feeds the cooling water to the internal combustion engine 10. The cooling water circulation passage 66 is a cooling water circulation passage for circulating the cooling water between the internal combustion engine 10 and the cooling water pump 61. The cooling water is an example of the cooling water.

[0033] The oil circulation device 70 includes an oil pump 71 and an oil circulation passage 72. The oil pump 71 pumps oil drawn in through an intake port and pumps the oil out of a discharge port. An example of the oil pump 71 is a so-called mechanical pump that is driven by rotation of the pump impeller 45A of the torque converter 45.

[0034] An upstream end of the oil circulation passage 72 is connected to the discharge port of the oil pump 71. A downstream end of the oil circulation passage 72 is connected to the suction port of the oil pump 71. In other words, the oil circulation passage 72 is a circular flow path that extends from the oil pump 71 and returns to the oil pump 71.

[0035] The above-described power transmission device 40 is located downstream of the oil circulation passage 72 as viewed from the oil pump 71. The oil flow path inside the case 41 of the power transmission device 40 forms part of the oil circulation passage 72. The oil that reaches the inside of the case 41 of the power transmission device 40 flows through each component housed in the case 41 and the hydraulic device 55. In other words, the oil discharged from the case 41 of the power transmission device 40 is oil discharged from the motor generator 30, etc.

[0036] The heat exchanger 75 is located in the cooling water circulation passage 66 downstream as viewed from the water jacket 15 of the internal combustion engine 10 and upstream as viewed from the cooling water pump 61. In addition, the heat exchanger 75 is located in the oil circulation passage 72 downstream as viewed from the oil pump 71 and upstream as viewed from the case 41 of the power transmission device 40. The cooling water passage in the heat exchanger 75 constitutes a part of the cooling water circulation passage 66. In addition, the oil passage in the heat exchanger 75 constitutes a part of the oil circulation passage 72. The heat exchanger 75 exchanges heat between the cooling water flowing through the heat exchanger 75 and the oil.

[0037] <Vehicle Electrical Configuration> 1, the vehicle 100 is equipped with an accelerator operation amount sensor 81, a vehicle speed sensor 82, a crank angle sensor 83, and a water temperature sensor 84. The vehicle 100 also is equipped with a current sensor 86, a voltage sensor 87, and a battery temperature sensor 88.

[0038] The accelerator operation amount sensor 81 detects an accelerator operation amount ACC, which is an operation amount of an accelerator pedal (not shown) operated by a driver. The vehicle speed sensor 82 detects a vehicle speed SP, which is the speed of the vehicle 100. The crank angle sensor 83 detects a crank angle SC, which is the angular position of the crankshaft 18. The water temperature sensor 84 detects a water temperature TW, which is the temperature of the cooling water discharged from the internal combustion engine 10. Specifically, the water temperature sensor 84 detects the temperature of the downstream end of the water jacket 15 as the water temperature TW. The current sensor 86 detects a current IB, which is a current input / output to / from the battery 57. The voltage sensor 87 detects a voltage VB, which is a terminal voltage of the battery 57. The battery temperature sensor 88 detects a battery temperature TB, which is the temperature of the battery 57.

[0039] As shown in FIG. 1, the vehicle 100 includes a control device 90. The control device 90 obtains a signal indicating an accelerator operation amount ACC from an accelerator operation amount sensor 81. The control device 90 obtains a signal indicating a vehicle speed SP from a vehicle speed sensor 82. The control device 90 obtains a signal indicating a crank angle SC from a crank angle sensor 83. The control device 90 obtains a signal indicating a water temperature TW from a water temperature sensor 84. The control device 90 obtains a signal indicating a current IB from a current sensor 86. The control device 90 obtains a signal indicating a voltage VB from a voltage sensor 87. The control device 90 obtains a signal indicating a battery temperature TB from a battery temperature sensor 88. The control device 90 calculates an engine rotation speed NE, which is the rotation speed of the crankshaft 18, based on the crank angle SC.

[0040] The control device 90 calculates the vehicle required driving force, which is a required value of driving force necessary for the vehicle 100 to travel, based on the accelerator operation amount ACC and the vehicle speed SP. The control device 90 determines the torque distribution between the internal combustion engine 10 and the motor generator 30 based on the vehicle required driving force. The control device 90 controls the output of the internal combustion engine 10 and the power running and regeneration of the motor generator 30 based on the torque distribution between the internal combustion engine 10 and the motor generator 30.

[0041] The control device 90 controls the internal combustion engine 10 by outputting a control signal to the internal combustion engine 10. Specifically, it executes various types of control such as adjustment of the opening of the throttle valve 23, adjustment of the ignition timing of the ignition device 24, adjustment of the amount of fuel injected from the port injection valve 26, adjustment of the amount of fuel injected from the in-cylinder injection valve 27, and adjustment of the amount of water injected from the water injection valve 29. In addition, the control device 90 outputs a control signal to the inverter 56 in order to control the motor generator 30. The control device 90 controls the motor generator 30 by adjusting the amount of power exchanged between the motor generator 30 and the battery 57 via the inverter 56.

[0042] The control device 90 controls the engagement state of the clutch 44 via the hydraulic device 55 by outputting a control signal to the hydraulic device 55. The control device 90 controls the engagement state of the lock-up clutch 45C of the torque converter 45 via the hydraulic device 55 by outputting a control signal to the hydraulic device 55. The control device 90 controls the gear ratio of the automatic transmission 46 via the hydraulic device 55 by outputting a control signal to the hydraulic device 55. The control device 90 also controls the cooling water pump 61 by outputting a control signal to the cooling water pump 61.

[0043] The control device 90 calculates the charging rate SOC of the battery 57 based on the current IB, the voltage VB, and the battery temperature TB. Specifically, the control device 90 calculates the charging rate SOC based on the following formula.

[0044] Equation (1): Charging rate SOC [%] = remaining capacity of battery 57 [Ah] / fully charged capacity of battery 57 [Ah] × 100 [%] In the above formula (1), the full charge capacity is calculated based on, for example, the voltage VB and the battery temperature TB of the battery 57. The remaining capacity is calculated based on, for example, the voltage VB and the current IB of the battery 57.

[0045] The control device 90 performs charging control of the battery 57. Through this charging control, the charging rate SOC of the battery 57 is controlled to be in a range between an upper limit SOCH and a lower limit SOCL. An example of the upper limit SOCH is 60 to 80%, and an example of the lower limit SOCL is 20 to 30%.

[0046] When the vehicle 100 travels, the control device 90 selects either the EV mode or the HV mode as the travel mode of the vehicle 100. Here, the EV mode is a travel mode in which the internal combustion engine 10 is stopped while the motor generator 30 is driven to travel the vehicle 100. Therefore, in the EV mode, the vehicle 100 is traveled by the driving force of the motor generator 30. Meanwhile, the HV mode is a travel mode of the vehicle 100 in which the internal combustion engine 10 is driven in addition to the motor generator 30 to travel the vehicle 100. Therefore, in the HV mode, the vehicle 100 is traveled by the driving force of the internal combustion engine 10 in addition to the driving force of the motor generator 30.

[0047] The control device 90 selects the EV mode, for example, when the charging rate SOC of the battery 57 has a sufficient margin and the above-mentioned vehicle required driving force is small. Examples of when the vehicle required driving force is small include when the vehicle 100 starts moving and when the vehicle 100 is running under a light load with low acceleration. On the other hand, the control device 90 selects the HV mode, for example, when the charging rate SOC of the battery 57 does not have a sufficient margin.

[0048] The control device 90 acquires the intake system temperature Z, which is the temperature of the intake passage 12, based on the operating state of the internal combustion engine 10. As a specific example, the control device 90 acquires the intake system temperature Z by calculating the intake system temperature Z based on an integrated value of the engine rotation speed NE from the present time until a certain period ago, an integrated value of the output of the internal combustion engine 10 from the present time until a certain period ago, a water temperature TW, etc. An example of the intake system temperature Z is the temperature at the downstream end of the intake passage 12. In this embodiment, the above process is an example of an acquisition process.

[0049] The control device 90 may be configured as a circuit including one or more processors that execute various processes according to a computer program (software). The control device 90 may also be configured as a circuit including one or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that execute at least a part of the various processes, or a combination thereof. The processor includes a CPU and memories such as RAM and ROM. The memory stores program codes or instructions that are configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any medium that can be accessed by a general-purpose or dedicated computer.

[0050] <Pump control> Next, a description will be given of pump control of the cooling water pump 61 executed by the control device 90. The control device 90 repeatedly executes pump control from when the control device 90 is started until when the control device 90 is stopped.

[0051] 3, when the control device 90 starts pump control, it executes the process of step S11. In step S11, the control device 90 judges whether or not the internal combustion engine 10 is stopped. In step S11, when the control device 90 judges that the internal combustion engine 10 is stopped (S11: YES), the control device 90 advances the process to step S12.

[0052] In step S12, the control device 90 determines whether the intake system temperature Z is lower than a predetermined threshold value B. Here, the threshold value B is determined, for example, as follows. First, a lower limit value of the intake system temperature Z at which it is determined that backfire may occur in the internal combustion engine 10 is obtained through experiments or the like. Then, a value that is a certain value lower than the obtained lower limit value of the intake system temperature Z is set as the threshold value B. An example of the threshold value B is several tens of degrees Celsius. In step S12, if the control device 90 determines that the intake system temperature Z is lower than the threshold value B (S12: YES), the control device 90 advances the process to step S21.

[0053] In step S21, the control device 90 outputs a control signal to the cooling water pump 61 to stop the cooling water pump 61. If the cooling water pump 61 is already stopped at the time of the processing of step S21, the control device 90 maintains the stopped state of the cooling water pump 61. Thereafter, the control device 90 ends the current pump control. Then, the control device 90 advances the processing to step S11 again.

[0054] On the other hand, if the control device 90 determines in step S11 that the internal combustion engine 10 is operating (S11: NO), the control device 90 advances the process to step S31. If the control device 90 determines in step S12 that the intake system temperature Z is equal to or higher than the threshold value B (S12: NO), the control device 90 advances the process to step S31.

[0055] In step S31, the control device 90 drives the cooling water pump 61 by outputting a control signal to the cooling water pump 61. If the cooling water pump 61 is driven at the time of processing step S31, the control device 90 maintains the driving state of the cooling water pump 61. In this embodiment, the processing of step S31 is a pump processing. Thereafter, the control device 90 ends the current pump control. Then, the control device 90 advances the processing to step S11 again.

[0056] <Drive switching control> Next, a description will be given of the driving switching control executed by the control device 90. When the vehicle 100 is driven, the control device 90 repeatedly executes the driving switching control.

[0057] As shown in FIG. 4, when the control device 90 starts the running switching control, it executes step S61. In step S61, the control device 90 judges whether the intake system temperature Z is lower than a predetermined specified temperature C. Here, the specified temperature C is determined, for example, as follows. First, a lower limit value of the intake system temperature Z at which it is determined that backfire may occur in the internal combustion engine 10 is obtained by an experiment or the like. Then, the obtained lower limit value of the intake system temperature Z is set as the specified temperature C. Therefore, in this embodiment, the specified temperature C is a value that is higher than the threshold value B of step S12 by a certain value. An example of the specified temperature C is several tens of degrees Celsius. In step S61, when the control device 90 judges that the intake system temperature Z is lower than the specified temperature C (S61: YES), the control device 90 advances the process to step S71.

[0058] In step S71, the control device 90 executes a normal driving process. In this normal driving process, the control device 90 selects either the EV mode or the HV mode as the driving mode of the vehicle 100 according to the charging rate SOC of the battery 57. When the HV mode is selected, the control device 90 controls the internal combustion engine 10 by referring to a predetermined driving control map. The driving control map indicates a combination of the engine rotation speed NE and the torque of the internal combustion engine 10 that minimizes the fuel consumption when the output of the internal combustion engine 10 is a certain output. The driving control map is created by obtaining a combination of the engine rotation speed NE and the torque of the internal combustion engine 10 in advance by an experiment or the like. The control device 90 stores the created driving control map in advance. After step S71, the control device 90 ends the current driving switching control. Then, the control device 90 advances the process to step S61 again.

[0059] On the other hand, in step S61, when the control device 90 determines that the intake system temperature Z is equal to or higher than the specified temperature C (S61: NO), the control device 90 advances the process to step S62. In other words, the control device 90 executes the processes from step S62 onward on the condition that the intake system temperature Z is equal to or higher than the specified temperature C.

[0060] In step S62, the control device 90 determines whether or not the EV mode is executable as the driving mode of the vehicle 100. For example, when both of the following two conditions are satisfied, the control device 90 determines that the EV mode is executable as the driving mode of the vehicle 100. The first condition is that the state of charge SOC is equal to or higher than a state of charge lower limit SOCL. The second condition is that the vehicle required driving force of the vehicle 100 is equal to or lower than the maximum value of the driving force of the motor generator 30. In step S62, when the control device 90 determines that the EV mode is executable as the driving mode of the vehicle 100 (S62: YES), the control device 90 advances the process to step S81.

[0061] In step S81, the control device 90 selects the EV mode as the driving mode of the vehicle 100. In other words, the control device 90 stops the internal combustion engine 10 and drives the vehicle 100 using the driving force of the motor generator 30. In this embodiment, the process of step S81 is an EV driving process. After step S81, the control device 90 ends the current driving switching control. Then, the control device 90 advances the process to step S61 again.

[0062] On the other hand, if the control device 90 determines in step S62 that the EV mode is not executable as the driving mode of the vehicle 100 (S62: NO), the control device 90 advances the process to step S91.

[0063] In step S91, the control device 90 selects the HV mode as the driving mode of the vehicle 100. At this time, the control device 90 reduces the driving force of the internal combustion engine 10 by a constant driving force compared to when the normal driving process of step S71 is executed. Also, the control device 90 increases the driving force of the motor generator 30 by a constant driving force compared to when the normal driving process of step S71 is executed. After step S91, the control device 90 ends the current driving switching control. Then, the control device 90 advances the process to step S61 again.

[0064] <Action of this embodiment> In the vehicle 100, when the internal combustion engine 10 is driven, a mixture of fuel and intake air is burned in the cylinder 11. Then, the temperature around the cylinder 11, specifically, the temperature in the vicinity of the cylinder 11 in the intake passage 12, increases due to the combustion of the mixture. Then, in the vehicle 100, as shown in FIG. 4, when the intake system temperature Z is equal to or higher than a specified temperature C and the EV mode is executable, the EV mode is selected as the driving mode of the vehicle 100 in step S81. In other words, on the condition that the intake system temperature Z is equal to or higher than the specified temperature C, the internal combustion engine 10 is stopped and the vehicle 100 is driven by the driving force of the motor generator 30. If the vehicle 100 runs in this manner with the internal combustion engine 10 stopped, a further increase in the temperature around the cylinder 11 due to the combustion of the mixture of fuel and intake air in the cylinder 11 is suppressed.

[0065] Furthermore, as shown in FIG. 3, in the vehicle 100, even if the internal combustion engine 10 is stopped, the cooling water pump 61 is driven when the intake system temperature Z is equal to or higher than the threshold value B. Here, the specified temperature C is a value higher than the threshold value B. Therefore, in a situation in which the EV mode is selected as the driving mode of the vehicle 100 in step S81 as described above, the cooling water pump 61 is driven regardless of whether the internal combustion engine 10 is running or not. In this way, the cooling water pump 61 is driven while the internal combustion engine 10 is stopped, and thus the cooling water circulates in the cooling water circulation passage 66. Then, while the internal combustion engine 10 is stopped, the temperature around the cylinder 11 decreases due to heat exchange with the cooling water circulating in the water jacket 15 of the cooling water circulation passage 66.

[0066] <Effects of this embodiment> (1) As described above, if the temperature around the cylinder 11 drops while the internal combustion engine 10 is stopped, the temperature around the cylinder 11 is prevented from becoming excessively high when the internal combustion engine 10 starts operating again, even if the internal combustion engine 10 subsequently starts operating as the vehicle 100 runs. As a result, the occurrence of backfire in the internal combustion engine 10 immediately after it starts operating can be prevented.

[0067] (2) In vehicle 100, the EV mode is selected as the driving mode of vehicle 100 on the condition that the EV mode is executable, specifically, on the condition that the vehicle required driving force of vehicle 100 is equal to or less than the maximum value of the driving force of motor generator 30. This makes it possible to prevent the actual driving force of vehicle 100 from becoming smaller than the vehicle required driving force due to selection of the EV mode as the driving mode of vehicle 100.

[0068] (3) In the case where the EV mode cannot be implemented in the vehicle 100, the HV mode is selected as the driving mode of the vehicle 100. At this time, the driving force of the internal combustion engine 10 is reduced in the vehicle 100 compared to when the normal driving process of step S71 is executed. This reduces the amount of the mixture of fuel and intake air combusted in the cylinder 11. As a result, the increase in temperature around the cylinder 11 due to the combustion of the mixture of fuel and intake air in the cylinder 11 can be suppressed.

[0069] (4) In the vehicle 100, the cooling water pump 61 is stopped when the intake system temperature Z is lower than the threshold value B. This prevents the cooling water pump 61 from being driven unnecessarily while the internal combustion engine 10 is stopped, that is, prevents unnecessary consumption of electricity.

[0070] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0071] In the above embodiment, the pump control may be modified. For example, the threshold value B in step S12 may be set to the same value as the specified temperature C in step S61. Even in this configuration, in a situation where the EV mode is selected in step S81, the cooling water pump 61 can be driven regardless of whether the internal combustion engine 10 is driven or not.

[0072] In the above embodiment, the driving switching control may be changed. For example, in step S91, when the HV mode is selected as the driving mode of the vehicle 100, water may be injected from the water injection valve 29 into the intake passage 12. In this case, the water injected into the intake passage 12 is evaporated, thereby cooling the intake passage 12.

[0073] For example, in step S91, when the HV mode is selected as the driving mode of the vehicle 100, the internal combustion engine 10 may be controlled in the same manner as in the normal driving process of step S71. Even with this configuration, if a situation arises in which the process of step S81 is executed, the occurrence of backfire in the internal combustion engine 10 can be suppressed.

[0074] For example, the judgment condition in step S62 may be changed. As a specific example, the control device 90 may make an affirmative judgment in step S62 when one or more of the first and second conditions are satisfied. First, when the first condition is not satisfied, that is, even if a situation occurs in which the charging rate SOC is less than the charging rate lower limit SOCL, it is unlikely that the difference between the charging rate SOC and the charging rate lower limit SOCL will become excessively large. Therefore, even if an affirmative judgment is made in step S62 when only the second condition is satisfied, the influence is small. In addition, from the viewpoint of suppressing the occurrence of backfire in the internal combustion engine 10, it is effective to execute the process of step S81 even when the second condition is not satisfied, that is, even in a situation in which the actual driving force of the vehicle 100 is smaller than the vehicle required driving force. Therefore, when only the first condition is satisfied, an affirmative judgment may be made in step S62.

[0075] For example, if a negative determination is made in the process of step S61, the process of step S81 may be executed. In other words, the process of step S62 may be omitted. As described above, in the vehicle 100, it is unlikely that the charging rate SOC is less than the charging rate lower limit SOCL and the difference between the charging rate SOC and the charging rate lower limit SOCL becomes excessively large. Therefore, even if the charging rate SOC is less than the charging rate lower limit SOCL, the motor generator 30 may be able to be driven by electric power from the battery 57, provided that this is temporary.

[0076] For example, the specified temperature C in step S61 may be set to the same value as the threshold value B in step S12. Even in this configuration, in a situation in which the EV mode is selected in step S81, the cooling water pump 61 can be driven regardless of whether the internal combustion engine 10 is operating or not.

[0077] In the above embodiment, the intake system temperature Z is not limited to the temperature at the downstream end of the intake passage 12. For example, the intake system temperature Z may be the temperature in the intake passage 12 near the port injection valve 26 or the temperature in the intake passage 12 near the water injector 29.

[0078] In the above embodiment, the process of acquiring the intake system temperature Z may be changed. For example, in the vehicle 100, to acquire the intake system temperature Z, a temperature sensor for detecting the intake system temperature Z may be attached to the intake passage 12. In this case, the control device 90 may acquire the value detected by the temperature sensor as the intake system temperature Z.

[0079] In the above embodiment, the configuration of the vehicle 100 may be changed. For example, the coolant for the internal combustion engine 10 is not limited to cooling water, and oil or the like may be used. [Explanation of symbols]

[0080] Z…Intake system temperature 10. Internal combustion engine 11…Cylinder 12…Intake passage 13...Exhaust passage 15…Water jacket 18…Crankshaft 24…Ignition device 26…Port injection valve 27…In-cylinder injection valve 29...Water injection valve 30…Motor generator 40...Power transmission device 51…Differential 52...Drive wheel 55...Hydraulic system 60…Cooling water circulation device 61...Cooling water pump 62…Thermostat 63…Radiator 66…Cooling water circulation passage 68...Bypass passage 70...Oil circulation device 75...Heat exchanger 90...Control device 100…Vehicle

Claims

[Claim 1] An internal combustion engine that uses hydrogen as fuel and functions as a drive source; A motor generator that functions as a drive source; an electric refrigerant pump that pumps refrigerant to the internal combustion engine; a coolant circulation passage for circulating the coolant between the internal combustion engine and the coolant pump; A control device for controlling a vehicle comprising: An acquisition process for acquiring an intake system temperature, which is a temperature of an intake passage of the internal combustion engine; an EV driving process for stopping the internal combustion engine and driving the vehicle by the driving force of the motor generator on condition that the intake system temperature is equal to or higher than a predetermined specified temperature; a pump process for driving the refrigerant pump on the condition that the intake system temperature is equal to or higher than the specified temperature, regardless of whether the internal combustion engine is being driven or not. Vehicle control device.

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