vehicle

Abstract

To efficiently warm up a regulator with heat associated with expansion of hydrogen.SOLUTION: A vehicle VC comprises an internal combustion engine using hydrogen as fuel and a cooling mechanism 80. A main flow passage 82 is extended from a cooling object device and returned thereto through a regulator 35 of the internal combustion engine. A bypass flow passage 83 is extended from a point downstream of the cooling object device and upstream of the regulator 35 in the main flow passage 82 and connected to a point downstream of the regulator 35 in the main flow passage 82. A valve 84 is installed on a point downstream of the regulator 35 in the main flow passage 82. A control device 100 performs a valve closing process to close the valve 84 under a condition that a temperature of a coolant flowing out of the cooling object device is lower than a predetermined coolant temperature. The control device 100 also performs a valve opening process to open the valve 84 under a condition that the temperature of the coolant flowing out of the cooling object device is equal to or higher than the predetermined coolant temperature.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention is a vehicle. [Background technology]

[0002] Patent Document 1 describes a vehicle including an internal combustion engine and a cooling mechanism. The internal combustion engine has a fuel tank, a fuel pipe, a regulator, and an injector. The fuel tank stores high-pressure gaseous fuel. The fuel pipe constitutes a gaseous fuel passage connecting the fuel tank and the injector. The regulator reduces the pressure of the gaseous fuel flowing through the fuel pipe. The injector is attached to the fuel pipe downstream of the regulator. Meanwhile, the cooling mechanism has a flow path through which a coolant flows. The regulator is located on the flow path of the cooling mechanism. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-131947 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an internal combustion engine such as that described in Patent Document 1, when the temperature of the internal combustion engine is low, water adhering to the vicinity of the nozzle of the injector may freeze. In addition, in an internal combustion engine such as that described in Patent Document 1, hydrogen fuel may be used as the gas fuel. Hydrogen generates heat as it is decompressed and expanded in the regulator. Therefore, even if the temperature of the internal combustion engine is low, the injector can be warmed up relatively quickly. However, when the temperature of the internal combustion engine is low, the temperature of the coolant in the cooling mechanism is also low. Therefore, even if hydrogen generates heat, the heat may be collected by the coolant in the cooling mechanism, and the injector may not be warmed up properly. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides an internal combustion engine that uses hydrogen as fuel, a cooling mechanism having a flow path of a refrigerant for cooling a device to be cooled, and a control device that controls the cooling mechanism, wherein the internal combustion engine has a fuel pipe that is connected to a hydrogen tank and that constitutes a passage for the hydrogen, a regulator that is attached midway along the fuel pipe and that reduces the pressure of the hydrogen, and an injector that is attached to the fuel pipe downstream of the regulator, and the cooling mechanism has a pump that pressurizes the refrigerant, a main flow path that passes through the device to be cooled and the regulator and returns to the device to be cooled, and The vehicle has a bypass flow path that connects a portion of the main flow path that is downstream of the device to be cooled and upstream of the regulator to a portion of the main flow path that is downstream of the regulator, and a valve that is attached to the main flow path downstream of the upstream end of the bypass flow path, and the control device executes a valve closing process that closes the valve, on condition that the temperature of the refrigerant flowing out of the device to be cooled is lower than a predetermined specified refrigerant temperature, and a valve opening process that opens the valve, on condition that the temperature of the refrigerant is equal to or higher than the specified refrigerant temperature.

[0006] According to the above configuration, when the temperature of the refrigerant is lower than the specified refrigerant temperature, the refrigerant does not exchange heat with the regulator. This prevents the heat generated by the expansion of hydrogen from being carried away by the refrigerant. As a result, the regulator can be efficiently warmed by the heat generated by the expansion of hydrogen.

[0007] In the vehicle, the control device may execute the valve opening process when the temperature of the coolant is equal to or higher than the specified coolant temperature and the temperature of the hydrogen is lower than a predetermined lower limit fuel temperature.

[0008] In the above configuration, if the temperature of the hydrogen is lower than the lower limit fuel temperature, the regulator cannot be warmed up appropriately even if the hydrogen expands and generates heat. On the other hand, if the temperature of the refrigerant is equal to or higher than the specified refrigerant temperature, the regulator can be warmed up to approximately the specified refrigerant temperature by flowing the refrigerant through the regulator. In other words, according to the above configuration, when warming up using the heat of the refrigerant is more appropriate than warming up using the heat generated by hydrogen, the regulator temperature can be made appropriate by flowing the refrigerant through the regulator.

[0009] In the vehicle, the control device may execute the valve opening process when the temperature of the refrigerant is equal to or higher than the specified refrigerant temperature and the temperature of the hydrogen is equal to or higher than a predetermined upper fuel limit temperature as a value equal to or higher than the specified refrigerant temperature.

[0010] In the above configuration, if the temperature of the hydrogen is equal to or higher than the upper fuel limit temperature, there is a high possibility that the hydrogen will not be combusted as designed. Therefore, by flowing a coolant through the regulator, the temperature of the regulator and the hydrogen inside the regulator can be cooled to an appropriate temperature.

[0011] In the vehicle, the control device may estimate the temperature of the hydrogen based on a temperature of a coolant for the internal combustion engine. According to the above configuration, the temperature of hydrogen is estimated based on the temperature of the coolant for the internal combustion engine. The temperature of the coolant for the internal combustion engine can be obtained by a sensor that detects the temperature of the coolant. Therefore, it is not necessary to provide a separate sensor for detecting the temperature of hydrogen.

[0012] In the vehicle, the control device may estimate the temperature of the hydrogen based on the temperature of the regulator. According to the above configuration, the temperature of the hydrogen is estimated based on the temperature of the regulator. The temperature of the regulator can be obtained by attaching a sensor that detects the temperature to the regulator. Therefore, it is not necessary to provide a separate sensor that detects the temperature of the hydrogen.

[0013] In the vehicle described above, the internal combustion engine may further include a temperature sensor that detects a temperature of the hydrogen. According to the above configuration, the temperature of the hydrogen can be detected more accurately.

[0014] The vehicle may further include a motor generator as a drive source, and the control device may control the internal combustion engine and the motor generator, and when the temperature of the hydrogen is lower than the lower fuel limit temperature, the control device may execute an EV driving process to stop the internal combustion engine and drive the motor generator as a drive source.

[0015] According to the above configuration, when the temperature of the hydrogen fuel is lower than the lower limit fuel temperature, the motor generator is operated as a drive source. On the other hand, the internal combustion engine is not operated as a drive source. By not operating the internal combustion engine when it is cold in this way, it is possible to suppress the occurrence of problems that may occur when operating the internal combustion engine when it is cold. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram showing the overall configuration of a vehicle. [Diagram 2] FIG. 2 is a schematic diagram showing the overall configuration of an internal combustion engine. [Diagram 3] FIG. 3 is a schematic diagram showing the cooling mechanism. [Figure 4] FIG. 4 is a flowchart showing a series of processes according to the control program. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] (One embodiment) Hereinafter, an embodiment of a vehicle will be described with reference to the drawings. <Vehicle Overview> As shown in Fig. 1, the vehicle VC is equipped with a spark ignition type internal combustion engine 10. The vehicle VC also includes a first motor generator 71 and a second motor generator 72 that function as both an electric motor and a generator. Therefore, the vehicle VC is a so-called hybrid vehicle. In other words, the vehicle VC includes the internal combustion engine 10, the first motor generator 71, and the second motor generator 72 as drive sources.

[0018] <Configuration of an internal combustion engine> First, the overall configuration of the internal combustion engine 10 will be described. As shown in FIG. 2, the internal combustion engine 10 includes a cylinder block 11, a cylinder head 12, a piston 13, and a cylinder 14. The cylinder 14 is a cylindrical space defined inside the cylinder block 11. Both axial ends of the cylinder 14 are open to the outside of the cylinder block 11. The piston 13 is disposed in the cylinder 14. The top surface of the piston 13 faces a first axial end of the cylinder 14. The cylinder head 12 is connected to the cylinder block 11. The outer surface of the cylinder head 12 has a recess 15. The recess 15 faces the cylinder 14 in the axial direction of the cylinder 14. The wall surface of the cylinder block 11 that defines the cylinder 14, the wall surface of the recess 15, and the top surface of the piston 13 define a combustion chamber R. The cylinder head 12 has a water jacket WJ therein. The water jacket WJ is a passage through which cooling water of a cooling mechanism 80 described later flows.

[0019] The internal combustion engine 10 includes a connecting rod 16 and a crankshaft 17. The connecting rod 16 is connected to the piston 13. The connecting rod 16 extends in the opposite direction to the cylinder head 12, sandwiching the piston 13 therebetween. The crankshaft 17 is connected to the connecting rod 16. The crankshaft 17 and the connecting rod 16 convert the reciprocating motion of the piston 13 into rotational motion.

[0020] The cylinder head 12 has an intake port 18. The intake port 18 is a space defined inside the cylinder head 12. A first end of the intake port 18 opens toward the recess 15. A second end of the intake port 18 opens toward the outside of the cylinder head 12.

[0021] The cylinder head 12 has an exhaust port 19. The exhaust port 19 is a space defined inside the cylinder head 12. A first end of the exhaust port 19 opens toward the recess 15. A second end of the exhaust port 19 opens toward the outside of the cylinder head 12.

[0022] The internal combustion engine 10 includes an intake valve 20 and an exhaust valve 21. The intake valve 20 is a valve that opens and closes a first end of the intake port 18. The exhaust valve 21 is a valve that opens and closes a first end of the exhaust port 19.

[0023] In addition, although Figure 1 shows only one set of the combustion chamber R and the intake port 18 and exhaust port 19 connected to the combustion chamber R, the internal combustion engine 10 has multiple sets of the combustion chamber R and the intake port 18 and exhaust port 19 connected to the combustion chamber R, etc.

[0024] The internal combustion engine 10 has an intake passage 22 for drawing in outside air. The intake passage 22 is connected to a second end of the intake port 18. The intake passage 22 houses a throttle valve 23. The throttle valve 23 adjusts the intake air amount, which is the flow rate of air flowing through the intake passage 22, by changing the valve opening degree. The air drawn in from the intake passage 22 flows into the combustion chamber R via the intake port 18.

[0025] The internal combustion engine 10 is equipped with a port injector 24. The port injector 24 is attached to the cylinder head 12. Therefore, the port injector 24 is located downstream of the throttle valve 23 in the intake passage 22. The port injector 24 injects fuel into the intake port 18.

[0026] The internal combustion engine 10 is equipped with an in-cylinder injector 25. The in-cylinder injector 25 is attached to the cylinder head 12. The in-cylinder injector 25 injects fuel directly into the combustion chamber R.

[0027] The internal combustion engine 10 is equipped with an ignition plug 26. The ignition plug 26 is attached to the cylinder head 12. The ignition plug 26 is located between the intake port 18 and the exhaust port 19. The ignition plug 26 ignites the mixture introduced into the combustion chamber R by means of a spark.

[0028] The internal combustion engine 10 is equipped with an exhaust passage 27 which is a discharge path for exhaust gas generated by combustion in the combustion chamber R. The exhaust passage 27 is connected to a second end of the exhaust port 19. The exhaust passage 27 accommodates an exhaust purification catalyst 28. The exhaust purification catalyst 28 purifies, for example, nitrogen oxides in the exhaust gas.

[0029] The internal combustion engine 10 also includes a fuel supply device 30. The fuel supply device 30 includes a hydrogen tank 31, a fuel pipe 32, and a regulator 35. The hydrogen tank 31 is a tank that stores hydrogen, which is a fuel, under high pressure. The fuel pipe 32 constitutes a passage for hydrogen. The fuel pipe 32 is made up of a first fuel pipe 33 and a second fuel pipe 34. A first end of the first fuel pipe 33 is connected to the hydrogen tank 31. Furthermore, a second end of the first fuel pipe 33 is connected to the in-cylinder injector 25. The regulator 35 is located midway through the first fuel pipe 33. The regulator 35 reduces the pressure of the hydrogen.

[0030] A first end of the second fuel pipe 34 is connected to a portion of the first fuel pipe 33 closer to the port injector 24 than the regulator 35. A second end of the second fuel pipe 34 is connected to the in-cylinder injector 25.

[0031] <Vehicle configuration> As shown in FIG. 1, the vehicle VC includes a first planetary gear mechanism 40, a ring gear shaft 45, a second planetary gear mechanism 50, a reduction mechanism 62, a differential mechanism 63, and a plurality of drive wheels 64.

[0032] The first planetary gear mechanism 40 includes a sun gear 41, a ring gear 42, a plurality of pinion gears 43, and a carrier 44. The sun gear 41 is an external gear. The sun gear 41 is connected to the first motor generator 71. The ring gear 42 is an internal gear, and is located coaxially with the sun gear 41. Each pinion gear 43 is located between the sun gear 41 and the ring gear 42. Each pinion gear 43 meshes with both the sun gear 41 and the ring gear 42. The carrier 44 supports the pinion gear 43. The pinion gear 43 is rotatable on its own axis, and is revolved by rotating together with the carrier 44. The carrier 44 is connected to the crankshaft 17.

[0033] The ring gear shaft 45 is connected to the ring gear 42. The ring gear shaft 45 is also connected to drive wheels 64 via a reduction mechanism 62 and a differential mechanism 63. The reduction mechanism 62 reduces the rotation speed of the ring gear shaft 45 and outputs it. The differential mechanism 63 allows a difference in rotation speed to occur between the left and right drive wheels 64.

[0034] The second planetary gear mechanism 50 includes a sun gear 51, a ring gear 52, a plurality of pinion gears 53, a carrier 54, and a case 55. The sun gear 51 is an external gear. The sun gear 51 is connected to the second motor generator 72. The ring gear 52 is an internal gear and is located coaxially with the sun gear 51. The ring gear 52 is connected to the ring gear shaft 45. Each pinion gear 53 is located between the sun gear 51 and the ring gear 52. Each pinion gear 53 meshes with both the sun gear 51 and the ring gear 52. The carrier 54 supports the pinion gear 53. The pinion gear 53 is rotatable. The carrier 54 is fixed to the case 55. Therefore, the pinion gear 53 is not capable of revolving.

[0035] The vehicle VC includes a battery 75, a first inverter 76, and a second inverter 77. The battery 75 is a secondary battery. The first inverter 76 performs AC-DC power conversion between the first motor generator 71 and the battery 75. The first inverter 76 also adjusts the amount of power exchanged between the first motor generator 71 and the battery 75. The second inverter 77 performs AC-DC power conversion between the second motor generator 72 and the battery 75. The second inverter 77 adjusts the amount of power exchanged between the second motor generator 72 and the battery 75.

[0036] 3, the vehicle VC includes a cooling mechanism 80. The cooling mechanism 80 cools the differential mechanism 63, the first motor generator 71, and the second motor generator 72, which are devices to be cooled. The cooling mechanism 80 includes a pump 81, a main flow path 82, a bypass flow path 83, a valve 84, and a radiator 85.

[0037] The pump 81 is an electric pump that pumps cooling oil as a refrigerant. The main flow path 82 is a flow path that runs from the pump 81 through the device to be cooled and the regulator 35 and returns to the device to be cooled. The upstream end of the main flow path 82 is connected to the discharge port of the pump 81. The downstream end of the main flow path 82 is connected to the suction port of the pump 81. The differential mechanism 63, the first motor generator 71, and the second motor generator 72, which are the devices to be cooled, are located on the main flow path 82. The regulator 35 is located on the main flow path 82 downstream of the device to be cooled.

[0038] The bypass flow passage 83 connects from a location of the main flow passage 82 downstream of the device to be cooled and upstream of the regulator 35 to a location of the main flow passage 82 downstream of the regulator 35 .

[0039] The valve 84 is attached to the main flow path 82 at a location downstream of the upstream end of the bypass flow path 83. The valve 84 is also attached to the main flow path 82 upstream of the regulator 35. When the valve 84 is in an open state, the refrigerant flows downstream of the valve 84 in the main flow path 82. When the valve 84 is in a closed state, the refrigerant does not flow downstream of the valve 84 in the main flow path 82.

[0040] The radiator 85 exchanges heat between the cooling oil flowing inside the radiator 85 and the air outside the radiator 85. The radiator 85 is attached to a portion of the main flow path 82 that is downstream of the regulator 35 and upstream of the downstream end of the bypass flow path 83. In Fig. 3, the flow of the cooling oil is indicated by dashed double-dashed arrows.

[0041] As shown in FIG. 1, the vehicle VC is equipped with an accelerator operation amount sensor 95, a vehicle speed sensor 96, a refrigerant temperature sensor 97, a hydrogen temperature sensor 98, and a power switch 99. The accelerator operation amount sensor 95 detects the accelerator operation amount ACC, which is the amount of operation of the accelerator pedal operated by the driver. The vehicle speed sensor 96 detects the vehicle speed V, which is the speed of the vehicle VC. The refrigerant temperature sensor 97 detects the refrigerant temperature CT, which is the temperature of the cooling oil, which is the refrigerant of the cooling mechanism 80. Specifically, the refrigerant temperature sensor 97 detects the temperature of the cooling water downstream of the device to be cooled and upstream of the regulator 35 in the main flow path 82 as the refrigerant temperature CT. In other words, the refrigerant temperature CT is the temperature of the refrigerant flowing out from the device to be cooled. The hydrogen temperature sensor 98 detects the hydrogen temperature HT, which is the temperature of hydrogen, which is the fuel of the internal combustion engine 10. The hydrogen temperature sensor 98 is attached to a portion of the fuel pipe 32, upstream of the regulator 35. The power switch 99 transmits a start request R1 when the power switch 99 is turned on while the power of the vehicle VC is off. The power switch 99 transmits a stop request R2 when the power switch 99 is turned off while the power of the vehicle VC is on.

[0042] <Control device> As shown in FIG. 1, the vehicle VC is equipped with a control device 100. The control device 100 controls the internal combustion engine 10, the first motor generator 71, the second motor generator 72, and the cooling mechanism 80. The control device 100 acquires a signal indicating an accelerator operation amount ACC from an accelerator operation amount sensor 95. The control device 100 acquires a signal indicating a vehicle speed V from a vehicle speed sensor 96. The control device 100 acquires signals indicating a current IB and a battery temperature TB of the battery 75 from the battery 75. The control device 100 acquires a signal indicating a refrigerant temperature CT from a refrigerant temperature sensor 97. The control device 100 acquires a signal indicating a hydrogen temperature HT from a hydrogen temperature sensor 98. The control device 100 acquires a signal indicating a start request R1 and a signal indicating a stop request R2 from a power switch 99.

[0043] The control device 100 includes a CPU 101, a peripheral circuit 102, a ROM 103, a storage device 104, and a bus 105. The bus 105 connects the CPU 101, the peripheral circuit 102, the ROM 103, and the storage device 104 so that they can communicate with each other. The peripheral circuit 102 includes a circuit that generates a clock signal that regulates internal operations, a power supply circuit, a reset circuit, and the like. The ROM 103 stores various programs in advance for the CPU 101 to execute various controls. The CPU 101 controls the internal combustion engine 10, the first motor generator 71, the second motor generator 72, and the cooling mechanism 80 by executing the various programs stored in the ROM 103.

[0044] <Control by driving program> The ROM 103 stores a drive program for driving the internal combustion engine 10, the first motor generator 71, and the second motor generator 72. When the CPU 101 acquires a start request R1, it repeatedly executes the drive program.

[0045] The CPU 101 calculates a vehicle required driving force, which is a required value of driving force necessary for the vehicle VC to travel, based on the accelerator operation amount ACC and the vehicle speed V. The CPU 101 determines the torque distribution of the internal combustion engine 10, the first motor generator 71, and the second motor generator 72, based on the vehicle required driving force. The CPU 101 controls the output of the internal combustion engine 10 and the power running and regeneration of the first motor generator 71 and the second motor generator 72, based on the torque distribution of the internal combustion engine 10, the first motor generator 71, and the second motor generator 72.

[0046] The CPU 101 calculates a target value of the output of the internal combustion engine 10 based on the torque distribution of the internal combustion engine 10, the first motor generator 71, and the second motor generator 72. The CPU 101 outputs a control signal to the internal combustion engine 10 based on the target value of the output of the internal combustion engine 10. As a result, the CPU 101 controls the opening of the throttle valve 23, the fuel injection amount from the in-cylinder injector 25, the fuel injection amount from the port injector 24, the ignition timing of the spark plug 26, and the like. The CPU 101 also controls the first motor generator 71 via the first inverter 76 by outputting a control signal to the first inverter 76. Furthermore, the CPU 101 controls the second motor generator 72 via the second inverter 77 by outputting a control signal to the second inverter 77.

[0047] In determining the torque distribution, the CPU 101 calculates the charge rate of the battery 75 and an input upper limit value. The CPU 101 calculates the charge rate based on an integrated value of the current IB. The CPU 101 also calculates an input upper limit value, which is the maximum allowable power that may be charged to the battery 75, based on the calculated charge rate and the battery temperature TB. The input upper limit value is expressed as zero or a positive value, and the larger the absolute value, the larger the power that is allowed to be charged to the battery 75. The CPU 101 determines the torque distribution of the internal combustion engine 10, the first motor generator 71, and the second motor generator 72 so that the charge rate of the battery 75 is maintained within a certain control range.

[0048] <Control by control program> The ROM 103 stores a control program for controlling the internal combustion engine 10, the first motor generator 71, the second motor generator 72, and the cooling mechanism 80 based on the coolant temperature CT. When the CPU 101 acquires a start request R1, the CPU 101 repeatedly executes the control program.

[0049] As shown in FIG. 4, when the control program is started, the CPU 101 first performs the process of step S11. In step S11, the CPU 101 judges whether the refrigerant temperature CT is equal to or higher than a predetermined specified refrigerant temperature SCT. The specified refrigerant temperature SCT is preset as follows by tests or simulations. The specified refrigerant temperature SCT is set as a temperature at which the amount of heat transferred to the internal combustion engine 10 is not excessively reduced among the heat generated when the refrigerant flows to the regulator 35 of the main flow path 82 and the hydrogen expands as it is decompressed by the regulator 35. Specifically, the specified refrigerant temperature SCT is set as a temperature of 10 degrees or less. If the refrigerant temperature CT is equal to or higher than the specified refrigerant temperature SCT (S11: YES), the CPU 101 advances the process to step S12.

[0050] In step S12, CPU 101 determines whether hydrogen temperature HT is lower than a predetermined fuel lower limit temperature FLT. The fuel lower limit temperature FLT is preset through testing or simulation as a temperature at which regulator 35 cannot be adequately warmed even if hydrogen expands and generates heat. Specifically, fuel lower limit temperature FLT is set as a temperature below freezing. If hydrogen temperature HT is lower than fuel lower limit temperature FLT (S12: YES), CPU 101 advances the process to step S13.

[0051] In step S13, the CPU 101 performs EV driving processing. In the EV driving processing, the CPU 101 sets the torque distribution of the internal combustion engine 10 to 0%, and sets the sum of the torque distributions of the first motor generator 71 and the second motor generator 72 to 100%. As a result, regardless of the torque distribution calculated by the above-mentioned drive program, the CPU 101 forcibly sets the torque distribution of the internal combustion engine 10 to 0% and drives the first motor generator 71 and the second motor generator 72. That is, in the EV driving processing, the CPU 101 stops the internal combustion engine 10 and drives the first motor generator 71 and the second motor generator 72 as drive sources. After that, the CPU 101 advances the processing to step S14.

[0052] In step S14, CPU 101 performs a process to open valve 84. That is, CPU 101 performs the process to open valve on the condition that refrigerant temperature CT is equal to or higher than specified refrigerant temperature SCT. In this embodiment, CPU 101 performs the process to open valve when refrigerant temperature CT is equal to or higher than specified refrigerant temperature SCT and hydrogen temperature HT is lower than fuel lower limit temperature FLT. In the process to open valve, CPU 101 opens valve 84. This allows cooling oil to flow downstream of valve 84 in main flow path 82. CPU 101 then ends the series of processes.

[0053] Meanwhile, in step S12, if the hydrogen temperature HT is equal to or higher than the fuel lower limit temperature FLT (S12: NO), the CPU 101 advances the process to step S15. In step S15, normal driving process is performed. In the normal driving process, the CPU 101 drives the internal combustion engine 10, the first motor generator 71, and the second motor generator 72 with the torque distribution calculated by the drive program described above. Note that, if the EV driving process in step S13 described above was being executed before the process of step S15, the CPU 101 cancels the EV driving process in this step S15. Thereafter, the CPU 101 advances the process to step S16.

[0054] In step S16, CPU 101 determines whether hydrogen temperature HT is higher than a predetermined fuel upper limit temperature FHT. Fuel upper limit temperature FHT is determined in advance by testing or simulation as a temperature at which hydrogen combustion does not occur as designed. This fuel upper limit temperature FHT is a temperature significantly higher than specified coolant temperature SCT, and is determined to be, for example, a value of 100 degrees or higher. If hydrogen temperature HT is higher than fuel upper limit temperature FHT (S16: YES), CPU 101 advances the process to step S14. That is, CPU 101 performs valve opening process when coolant temperature CT is higher than specified coolant temperature SCT and hydrogen temperature HT is higher than fuel upper limit temperature FHT.

[0055] Also, in step S11, if the refrigerant temperature CT is lower than the specified refrigerant temperature SCT (S11: NO), the CPU 101 advances the process to step S17. That is, the CPU 101 performs the valve closing process on the condition that the refrigerant temperature CT is lower than the specified refrigerant temperature SCT. Furthermore, in step S16, if the hydrogen temperature HT is lower than the fuel upper limit temperature FHT (S16: NO), the CPU 101 advances the process to step S17. That is, even if the refrigerant temperature CT is higher than the specified refrigerant temperature SCT, the CPU 101 performs the valve closing process if the hydrogen temperature HT is lower than the fuel upper limit temperature FHT. In step S17, the CPU 101 performs the valve closing process of the valve 84. In the valve closing process, the CPU 101 closes the valve 84. Thereafter, the CPU 101 ends the series of processes.

[0056] <Operation of the embodiment> According to the embodiment described above, in the valve opening process of step S14, the CPU 101 opens the valve 84. This causes the cooling oil to flow into the main flow path 82. Therefore, the cooling oil flowing through the main flow path 82 exchanges heat with the regulator 35 located on the main flow path 82.

[0057] On the other hand, in the valve closing process in step S17, the CPU 101 closes the valve 84. This causes the cooling oil to stop flowing through the main flow path 82. Therefore, the cooling oil does not exchange heat with the regulator 35.

[0058] <Effects of the embodiment> (1) According to the above embodiment, the CPU 101 performs the valve closing process on the condition that the refrigerant temperature CT is lower than the specified refrigerant temperature SCT, i.e., after a negative determination in step S11. On the other hand, the CPU 101 performs the valve opening process on the condition that the refrigerant temperature CT is equal to or higher than the specified refrigerant temperature SCT, i.e., after a positive determination in step S11. Therefore, when the refrigerant temperature CT is lower than the specified refrigerant temperature SCT, the refrigerant does not exchange heat with the regulator 35. This prevents the heat accompanying the expansion of hydrogen from being carried away by the refrigerant. As a result, the regulator 35 can be efficiently warmed by the heat accompanying the expansion of hydrogen.

[0059] (2) According to the above embodiment, the CPU 101 performs the valve opening process when the refrigerant temperature CT is equal to or higher than the specified refrigerant temperature SCT and the hydrogen temperature HT is lower than the fuel lower limit temperature FLT. That is, the valve opening process is performed after the affirmative determination in step S11 and the affirmative determination in step S12. When the hydrogen temperature HT is lower than the fuel lower limit temperature FLT, the regulator 35 cannot be warmed up appropriately even if hydrogen expands and generates heat. On the other hand, when the refrigerant temperature CT is equal to or higher than the specified refrigerant temperature SCT, the regulator 35 can be warmed up to about the specified refrigerant temperature SCT by flowing the refrigerant through the regulator 35. That is, according to the above embodiment, when warming up using the heat of the refrigerant is more appropriate than warming up using the heat generated by hydrogen, the temperature of the regulator 35 can be made appropriate by flowing the refrigerant through the regulator 35.

[0060] (3) According to the above embodiment, the CPU 101 performs the valve opening process when the refrigerant temperature CT is equal to or higher than the specified refrigerant temperature SCT and the hydrogen temperature HT is equal to or higher than the fuel upper limit temperature FHT. That is, the valve opening process is performed after the affirmative determinations in steps S11 and S15. If the hydrogen temperature HT is equal to or higher than the fuel upper limit temperature FHT, there is a high possibility that the hydrogen will not be combusted as designed. Therefore, by flowing the refrigerant through the regulator 35, the regulator 35 and the hydrogen in the regulator 35 can be cooled to an appropriate temperature.

[0061] When the hydrogen temperature HT is equal to or higher than the fuel upper limit temperature FHT, the temperature of the coolant exchanging heat with the regulator 35 is also considerably high. In this situation, the valve opening process is performed to allow the coolant to flow into the radiator 85, thereby preventing the coolant from overheating.

[0062] (4) According to the above embodiment, the internal combustion engine 10 has the hydrogen temperature sensor 98. Therefore, the hydrogen temperature HT can be detected more accurately. (5) According to the above embodiment, the CPU 101 performs EV driving processing when the hydrogen temperature HT is lower than the fuel lower limit temperature FLT. In the EV driving processing, the CPU 101 stops the internal combustion engine 10 and drives the first motor generator 71 and the second motor generator 72 as drive sources. Therefore, when the internal combustion engine 10 is cold enough that the hydrogen temperature HT is lower than the fuel lower limit temperature FLT, the internal combustion engine 10 is not driven. This makes it possible to suppress the occurrence of problems that may occur when the internal combustion engine 10 is driven when it is cold.

[0063] The first motor generator 71 and the second motor generator 72 generate heat as they are driven. This heat is transmitted to the fuel pipe 32, the regulator 35, etc., causing the hydrogen temperature HT to rise. Therefore, by continuing the EV driving process, the situation in which the hydrogen temperature HT is lower than the fuel lower limit temperature FLT is resolved.

[0064] (Other embodiments) The above embodiment can be modified as follows: The embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0065] The vehicle VC may have a single motor generator as a drive source. The vehicle VC does not necessarily have to have the first motor generator 71 and the second motor generator 72 as a drive source. In this case, the vehicle VC has the internal combustion engine 10 as a drive source, and the CPU 101 may omit the processes of steps S13 and S15.

[0066] The refrigerant of the cooling mechanism 80 is not limited to cooling oil. Furthermore, the devices to be cooled by the cooling mechanism 80 are not limited to the differential mechanism 63, the first motor generator 71, and the second motor generator 72. For example, the device to be cooled by the cooling mechanism 80 may be the internal combustion engine 10, and the refrigerant of the cooling mechanism 80 may be the cooling water of the internal combustion engine 10.

[0067] The hydrogen temperature HT is not limited to being detected by the hydrogen temperature sensor 98. For example, if the vehicle VC is equipped with a sensor that detects the temperature of the coolant for the internal combustion engine 10, the CPU 101 may estimate the hydrogen temperature HT based on the temperature of the coolant for the internal combustion engine 10. In this case, the temperature of the coolant for the internal combustion engine 10 can be obtained by a sensor that detects the temperature of the coolant. Therefore, it is not necessary to provide a separate sensor that detects the temperature of the hydrogen. Note that when estimating the hydrogen temperature HT, the temperature of the coolant for the internal combustion engine 10 may be used as the estimated value of the hydrogen temperature HT directly, or the hydrogen temperature HT may be estimated to be higher the higher the temperature of the coolant for the internal combustion engine 10.

[0068] Also, for example, if the vehicle VC is equipped with a sensor that detects the temperature of regulator 35, CPU 101 may estimate hydrogen temperature HT based on the temperature of regulator 35. In this case, the temperature of regulator 35 can be obtained by the sensor that detects the temperature of regulator 35. Therefore, it is not necessary to provide a separate sensor that detects the temperature of hydrogen. In these cases, internal combustion engine 10 may not have hydrogen temperature sensor 98. Note that, in this modified example, it is preferable to measure the temperature of the portion of regulator 35 through which hydrogen flows before pressure reduction with a temperature sensor. On the other hand, if the temperature of the portion of regulator 35 through which hydrogen flows after pressure reduction is measured with a temperature sensor, it is possible to estimate hydrogen temperature HT by subtracting the heat generated from the measurement value of the temperature sensor, in anticipation of heat generation as hydrogen expands.

[0069] The CPU 101 does not necessarily have to execute the valve opening process when the hydrogen temperature HT is equal to or higher than the fuel upper limit temperature FHT. Specifically, in the above embodiment, the CPU 101 may omit the process of step S16. In this modified example, it is sufficient to determine whether to execute the valve opening process or the valve closing process depending on, for example, the refrigerant temperature CT.

[0070] The CPU 101 may not execute the EV driving process when the hydrogen temperature HT is lower than the fuel lower limit temperature FLT. Specifically, in the above embodiment, the process of step S13 may be omitted. In this case, it is sufficient to determine whether to execute the EV driving process and the torque distribution of each drive source, etc., based on other conditions.

[0071] When the hydrogen temperature HT is lower than the fuel lower limit temperature FLT, the CPU 101 does not necessarily have to execute the valve opening process. Specifically, in the embodiment, the processes of steps S12, S13, and S15 may be omitted, and the CPU 101 may determine whether to execute the valve opening process or the valve closing process based on the magnitude relationship between the hydrogen temperature HT and the fuel upper limit temperature FHT.

[0072] The CPU 101 may determine whether to perform the valve opening process or the valve closing process regardless of the hydrogen temperature HT. In other words, the processes in steps S12, S13, S15, and S16 in the above embodiment may be omitted.

[0073] The CPU 101 may perform the EV driving process on the condition that the vehicle VC is stopped. In this case, it is possible to prevent the internal combustion engine 10 from stopping while the vehicle VC is traveling. Therefore, it is possible to prevent the passengers of the vehicle VC from feeling uncomfortable due to the internal combustion engine 10 suddenly stopping while the vehicle VC is traveling. [Explanation of symbols]

[0074] 10. Internal combustion engine 24…Port injector 25…In-cylinder injector 30…Fuel supply device 31...Hydrogen tank 32…Fuel piping 35…Regulator 71…First motor generator 72…Second motor generator 80…Cooling mechanism 81…Pump 82…Main flow path 83...Bypass flow path 84…Valve 97...Refrigerant temperature sensor 98...Hydrogen temperature sensor 100...Control device CT…refrigerant temperature FHT…Fuel upper limit temperature FLT…Fuel lower limit temperature HT…Hydrogen temperature SCT…Specified refrigerant temperature VC…Vehicle

Claims

1. The present invention relates to an internal combustion engine that uses hydrogen as fuel, a cooling mechanism having a flow path for a refrigerant for cooling a device to be cooled, and a control device that controls the cooling mechanism. The internal combustion engine includes: a fuel pipe connected to a hydrogen tank and constituting a passage for the hydrogen; a regulator attached midway through the fuel pipe to reduce the pressure of the hydrogen; an injector attached to the fuel pipe downstream of the regulator, The cooling mechanism includes: A pump that pumps the refrigerant; a main flow path that passes through the device to be cooled and the regulator and returns to the device to be cooled; a bypass flow path that is connected from a portion of the main flow path that is downstream of the device to be cooled and upstream of the regulator to a portion of the main flow path that is downstream of the regulator; a valve attached to the main flow path downstream of the upstream end of the bypass flow path, The control device includes: a valve closing process for closing the valve on condition that a temperature of the refrigerant flowing out from the device to be cooled is lower than a predetermined specified refrigerant temperature; and executing a valve opening process for opening the valve on the condition that the temperature of the refrigerant is equal to or higher than the specified refrigerant temperature. vehicle.

2. The control device executes the valve opening process when the temperature of the coolant is equal to or higher than the specified coolant temperature and the temperature of the hydrogen is lower than a predetermined lower limit fuel temperature.

2. The vehicle of claim 1.

3. The control device executes the valve opening process when the temperature of the coolant is equal to or higher than the specified coolant temperature and the temperature of the hydrogen is equal to or higher than a fuel upper limit temperature that is predetermined as a value equal to or higher than the specified coolant temperature.

2. The vehicle of claim 1.

4. The control device estimates the temperature of the hydrogen based on a temperature of a cooling water of the internal combustion engine. A vehicle according to claim 2 or claim 3.

5. The control device estimates the temperature of the hydrogen based on the temperature of the regulator. A vehicle according to claim 2 or claim 3.

6. The internal combustion engine further includes a temperature sensor for detecting a temperature of the hydrogen. A vehicle according to claim 2 or claim 3.

7. Further comprising a motor generator as a drive source; the control device controls the internal combustion engine and the motor generator, The control device executes an EV driving process to stop the internal combustion engine and drive the motor generator as a drive source when the temperature of the hydrogen is lower than the lower limit fuel temperature.

3. A vehicle as claimed in claim 2.

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