Hybrid vehicle

Abstract

To reduce an amount of heat radiation from a capacitor during EV travel and to continue the EV travel, in a hybrid vehicle including an engine-driven cooling fan.SOLUTION: A hybrid vehicle 100 capable of traveling in an HV mode and an EV mode includes: a radiator 16; an air conditioning device 200 including a capacitor 42 and a pressure sensor 55 and configured to perform air conditioning in a room; a cooling fan 17 configured to operate according to rotation of an engine 11 and to blow cooling air to the radiator 16 and the capacitor 42; and a control unit 80 configured to control an operation of the engine 11 and the air conditioning device 200. The control unit 80 reduces an amount of heat radiation from the capacitor 42 when a cooler high-pressure detected by the pressure sensor 55 during traveling in the EV mode becomes equal to or higher than a first pressure PS1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to control of an air conditioner for a hybrid vehicle. [Background technology]

[0002] Vehicles are in use that use a cooling fan driven by the engine to dissipate heat from the condenser in the refrigeration cycle. In such vehicles, when the engine speed is low, the amount of air sent to the condenser is reduced, and the pressure in the refrigeration cycle increases, causing the air conditioner to stop. To address this issue, a vehicle has been proposed that is provided with an electric auxiliary fan in addition to the engine-driven cooling fan, and when the engine speed is low, the auxiliary fan's air volume is increased to ensure sufficient heat dissipation from the condenser (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-157451 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, hybrid vehicles have come into use that can run in two modes: HV mode, where the vehicle runs on an engine and a vehicle drive motor, and EV mode, where the engine is stopped and the vehicle runs on the motor. These hybrid vehicles are equipped with an electric cooling fan so that the condenser can dissipate heat sufficiently even when the vehicle is running in EV mode.

[0005] On the other hand, even in the hybrid vehicles described above, some vehicles are equipped with an engine-driven cooling fan to ensure the amount of heat dissipation from the radiator that cools the engine coolant when climbing hills or towing. In such vehicles, when driving in EV mode with the engine stopped, the amount of ventilation through the condenser decreases, and the condenser is unable to dissipate sufficient heat, causing the pressure in the refrigeration cycle to rise, and it may not be possible to continue driving in EV mode.

[0006] Therefore, an object of the present disclosure is to reduce the amount of heat dissipated from a condenser during EV driving in a hybrid vehicle equipped with an engine-driven cooling fan, thereby enabling EV driving to be continued. [Means for solving the problem]

[0007] The hybrid vehicle disclosed herein is a hybrid vehicle capable of running in an HV mode in which the vehicle is driven by an engine and a motor for driving the vehicle, and an EV mode in which the engine is stopped and the vehicle is driven by the motor, and is equipped with an air conditioning system that includes a radiator that cools the coolant circulating inside the engine, a compressor, a condenser that condenses the refrigerant compressed by the compressor, and a pressure sensor that detects the pressure of the refrigerant compressed by the compressor, and that conditions the air inside the vehicle cabin, a cooling fan that operates in response to the rotation of the engine to blow cooling air to the radiator and the condenser, and a control unit that controls the operation of the engine and the air conditioning system, and is characterized in that the control unit reduces the amount of heat dissipated by the condenser when the pressure of the refrigerant detected by the pressure sensor while the vehicle is running in the EV mode becomes equal to or higher than a predetermined first pressure.

[0008] The amount of heat dissipated from the condenser is reduced while the vehicle is running as an EV, which suppresses the increase in refrigerant pressure while the vehicle is running as an EV, allowing the vehicle to continue running as an EV.

[0009] In the hybrid vehicle disclosed herein, when the refrigerant pressure detected by the pressure sensor while traveling in the EV mode is equal to or higher than the first pressure and the outside air temperature is less than a predetermined first temperature, the control unit may maintain the driving mode in the EV mode and reduce the amount of heat dissipation from the condenser, and when the refrigerant pressure detected by the pressure sensor while traveling in the EV mode is equal to or higher than the first pressure and the outside air temperature is equal to or higher than the first temperature, start the engine and switch the driving mode from the EV mode to the HV mode, and not reduce the amount of heat dissipation from the condenser.

[0010] This suppresses the increase in refrigerant pressure when the vehicle is running, allowing the vehicle to continue running, and when the outside temperature is high and cooling is required, the amount of heat dissipated by the condenser is increased to provide sufficient cooling.

[0011] In the hybrid vehicle of the present disclosure, the air conditioning unit includes an indoor fan that blows air into the vehicle cabin, and a switching damper that switches between an outside air introduction that introduces outside air into the vehicle cabin and an inside air circulation that circulates air within the vehicle cabin, and the control unit may reduce the amount of heat dissipated by the condenser by switching the switching damper to inside air circulation and increasing the duty of the indoor fan.

[0012] By improving the efficiency of the refrigeration cycle in this manner, the amount of heat dissipated by the condenser is reduced, so that the amount of heat dissipated by the condenser can be reduced without impairing the comfort of the passengers.

[0013] In the hybrid vehicle disclosed herein, the air conditioning system includes an evaporator through which a refrigerant flows to cool the air blown into the vehicle cabin, and the control unit may increase the set value of the refrigerant temperature at the evaporator outlet as the pressure of the refrigerant detected by the pressure sensor increases, and reduce the amount of heat dissipated by the condenser by reducing the upper limit rotation speed of the compressor.

[0014] In this way, by reducing the cooling load of the air conditioner, the amount of heat dissipated by the condenser is reduced, allowing EV driving to continue.

[0015] In the hybrid vehicle of the present disclosure, the control unit may reduce the amount of heat dissipation from the condenser by reducing the duty of the indoor fan as the refrigerant temperature at the evaporator outlet increases when the refrigerant pressure detected by the pressure sensor is higher than the first pressure and equal to or higher than a second pressure lower than an engine starting pressure.

[0016] If the refrigerant pressure is higher than the second pressure even after the efficiency of the refrigeration cycle is improved and the load on the air conditioner is reduced, the duty of the indoor fan is reduced to further reduce the load on the air conditioner, so that the increase in refrigerant pressure can be more effectively suppressed and driving in EV mode can be continued. . Effect of the Invention

[0017] The present disclosure is capable of reducing the amount of heat dissipated from a condenser during EV driving in a hybrid vehicle equipped with an engine-driven cooling fan, thereby enabling EV driving to be continued. [Brief description of the drawings]

[0018] [Figure 1] 1 is a system diagram showing a configuration of a hybrid vehicle according to an embodiment; [Diagram 2] 2 is a map showing a relationship between a cooler high pressure and a set value of a refrigerant temperature at an outlet of an evaporator, the relationship being stored in a memory of a control unit of the hybrid vehicle shown in FIG. 1; [Diagram 3] 2 is a map showing a relationship between a cooler high pressure and a compressor upper limit rotation speed stored in a memory of a control unit of the hybrid vehicle shown in FIG. 1; [Figure 4] 2 is a map showing a relationship between a refrigerant temperature at an evaporator outlet and an air volume of an indoor fan, the map being stored in a memory of a control unit of the hybrid vehicle shown in FIG. [Diagram 5] 2 is a flowchart showing the operation of the hybrid vehicle shown in FIG. [Figure 6] 6 is a flowchart showing the operation of the condenser heat radiation amount reduction process shown in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, a hybrid vehicle 100 according to an embodiment will be described with reference to the drawings. The hybrid vehicle 100 can run in an HV mode in which it runs using the engine 11 and a motor 61 for driving the vehicle, and in an EV mode in which it runs using the motor 61 with the engine 11 stopped.

[0020] As shown in Fig. 1, a hybrid vehicle 100 includes an engine cooling circuit 30, a refrigeration cycle circuit 50, a motor cooling circuit 70, a control unit 80, and an outside air temperature sensor 57. The engine cooling circuit 30 is a circuit that circulates coolant through the engine 11 to cool the engine 11. The refrigeration cycle circuit 50 is a circuit that compresses and expands the refrigerant to cool the vehicle interior. The motor cooling circuit 70 is a circuit that circulates coolant through the motor 61 and the PCU 62 to cool the motor 61 and the PCU 62.

[0021] First, we will explain the engine cooling circuit 30. In the engine cooling circuit 30, the engine 11, the three-way flow control valve 20, the heater core 13, the electric pump 14, the water heater 15, the thermostat 18, and the radiator 16 are provided in series in this order from the upstream side. The engine cooling circuit 30 is a flow path that passes the cooling water through each of these devices.

[0022] The engine 11 is a driving source of the hybrid vehicle 100. The engine 11 is provided with a cooling water flow passage 11a through which the cooling water flows. The engine 11 is also provided with an engine-driven pump 12 that is driven by the engine 11. The engine-driven pump 12 operates in conjunction with the engine 11. The discharge port of the engine-driven pump 12 is connected to the inlet of the cooling water flow passage 11a. The three-way flow control valve 20 is provided in the engine cooling circuit 30 between the engine 11 and the heater core 13. The three-way flow control valve 20 has three ports, a first port 21, a second port 22, and a third port 23. The three-way flow control valve 20 can switch the flow passage of the cooling water by opening and closing these three ports, respectively.

[0023] The heater core 13 is a heat exchanger that includes a coolant flow path 13a through which high-temperature coolant that has passed through the coolant flow path 11a of the engine 11 flows, and that heats the air to be blown into the vehicle cabin. The heater core 13 is disposed inside an outlet duct 47 that blows air into the vehicle cabin. A flow path switching damper 19 that switches between blocking and opening the flow of air to the heater core 13 is provided upstream of the heater core 13 inside the outlet duct 47.

[0024] The electric pump 14 is driven by a motor (not shown) and circulates the coolant through the engine cooling circuit 30. The water heater 15 is a heater for heating the coolant passing through the heater core 13 when the hybrid vehicle 100 runs in the EV mode. In other words, the water heater 15 is a heat source for heating the passenger compartment when the hybrid vehicle 100 runs in the EV mode. The water heater 15 includes a coolant flow path 15a through which the coolant flows.

[0025] The thermostat 18 is a switching valve that switches the flow of the cooling water to the radiator bypass pipe 38 when the temperature of the cooling water is low, and switches the flow path so that the cooling water flows to the radiator 16 when the temperature of the cooling water is high.

[0026] The radiator 16 is a heat exchanger that cools the cooling water with outside air. The radiator 16 has a cooling water flow path 16a through which the cooling water flows. The radiator 16 is attached to a radiator support 25 that is disposed in the front compartment at the front of the vehicle. The radiator support 25 covers all four sides of the radiator 16 and constitutes an air guide path that introduces outside air. A cooling fan 17 that is operated by the rotation of the engine 11 and blows cooling air to the radiator 16 is disposed behind the radiator 16.

[0027] The engine cooling circuit 30 is composed of the engine-driven pump 12, the cooling water flow path 11a of the engine 11, the engine outlet pipe 31, the three-way flow control valve 20, the heater core inlet pipe 32, the cooling water flow path 13a of the heater core 13, the heater core outlet pipe 33, the electric pump 14, the cooling water flow path 15a of the water heating heater 15, the water heating heater outlet pipe 35, the thermostat 18, the radiator inlet pipe 36, the cooling water flow path 16a of the radiator 16, the radiator outlet pipe 37, the engine-driven pump inlet pipe 39, the radiator bypass pipe 38, and the engine bypass pipe 34.

[0028] The engine outlet pipe 31 connects the outlet of the cooling water passage 11a of the engine 11 to the first port 21 of the three-way flow control valve 20. The heater core inlet pipe 32 connects the second port 22 of the three-way flow control valve 20 to the inlet of the cooling water passage 13a of the heater core 13. The heater core outlet pipe 33 connects the outlet of the cooling water passage 13a of the heater core 13 to the suction port of the electric pump 14. The discharge port of the electric pump 14 is connected to the inlet of the cooling water passage 15a of the water heating heater 15. The water heating heater outlet pipe 35 connects the outlet of the cooling water passage 15a of the water heating heater 15 to the thermostat 18. The radiator inlet pipe 36 connects the thermostat 18 to the inlet of the cooling water passage 16a of the radiator 16. The radiator outlet pipe 37 connects the outlet of the cooling water passage 16a of the radiator 16 to an engine-driven pump inlet pipe 39. The engine-driven pump inlet pipe 39 is connected to the suction port of the engine-driven pump 12. In addition, the radiator bypass pipe 38 connects the thermostat 18 to the engine-driven pump inlet pipe 39, bypassing the radiator 16. The engine bypass pipe 34 connects the water heating heater outlet pipe 35 of the engine cooling circuit 30 to the third port 23 of the three-way flow control valve 20 so as to bypass the engine 11.

[0029] Next, a description will be given of the refrigeration cycle circuit 50. The refrigeration cycle circuit 50 is composed of a compressor 41, a compressor outlet pipe 51, a condenser 42, a condenser outlet pipe 52, an expansion valve 43, an evaporator inlet pipe 53, an evaporator 44, and an evaporator outlet pipe 54.

[0030] Compressor 41 compresses the refrigerant to produce a high-temperature, high-pressure gas. Condenser 42 has a refrigerant flow path 42a inside and exchanges heat with outside air flowing outside, cooling and condensing the high-temperature, high-pressure gas refrigerant compressed by compressor 41 to produce a liquid. The discharge port of compressor 41 and the inlet of refrigerant flow path 42a of condenser 42 are connected by compressor outlet pipe 51. Condenser 42 is attached to radiator support 25, arranged in series with radiator 16 upstream of radiator 16 in the flow direction of outside air. Cooling fan 17 described above also blows cooling air to condenser 42.

[0031] The expansion valve 43 is a pressure reducing valve that adiabatically expands the refrigerant that has become a high-pressure liquid in the condenser 42. The expansion valve 43 is connected to the outlet of the refrigerant flow path 42a of the condenser 42 via a condenser outlet pipe 52.

[0032] The evaporator 44 has a refrigerant flow path 44a therein, and cools the air flowing outside by vaporizing the refrigerant flowing through the refrigerant flow path 44a. The evaporator 44 is connected to the expansion valve 43 by an evaporator inlet pipe 53. The evaporator 44 is disposed upstream of the heater core 13 in a blow-out duct 47 that blows air into the vehicle cabin, similar to the heater core 13. An interior fan 45 that blows air into the vehicle cabin is disposed upstream of the evaporator 44 in the blow-out duct 47. A switching damper 46 is provided upstream of the interior fan 45 to switch between an outside air introduction that introduces outside air to the interior fan 45 and an inside air circulation that introduces air inside the vehicle cabin to the interior fan 45. When the switching damper 46 is set to the outside air introduction, the outside air is introduced into the interior fan 45, and the outside air passes through the evaporator 44 to become cool air and is blown into the vehicle cabin. On the other hand, when the switching damper 46 is in the internal air circulation position, the air inside the vehicle cabin is introduced into the interior fan 45, and the air inside the vehicle cabin passes through the evaporator 44 to become cool air and is blown out into the vehicle cabin. The outlet of the refrigerant flow path 44a of the evaporator 44 is connected to the suction port of the compressor 41 by an evaporator outlet pipe 54.

[0033] The compressor 41, the condenser 42, the expansion valve 43, and the evaporator 44 constitute a refrigeration cycle that compresses and expands the refrigerant to cool the vehicle interior. The area between the outlet of the compressor 41 and the inlet of the expansion valve 43 is a high-pressure area where the refrigerant pressure is high. On the other hand, the area between the outlet of the expansion valve 43 and the suction port of the compressor 41 is a low-pressure area where the refrigerant pressure is low. The compressor outlet pipe 51 is provided with a pressure sensor 55 that detects the pressure of the refrigerant in the high-pressure area. The refrigerant pressure detected by the pressure sensor 55 is called the "cooler high pressure". The evaporator outlet pipe 54 is provided with a temperature sensor 56 that detects the refrigerant temperature at the outlet of the evaporator 44.

[0034] Furthermore, the compressor 41, the condenser 42, the expansion valve 43, the evaporator 44, the indoor fan 45, the switching damper 46, the heater core 13, the flow path switching damper 19, the pressure sensor 55, and the temperature sensor 56 constitute an air conditioner 200.

[0035] Next, we will explain the motor cooling circuit 70. The motor cooling circuit 70 is made up of the motor 61, a motor outlet pipe 73, the PCU 62, a PCU outlet pipe 74, the coolant pump 63, a coolant pump outlet pipe 71, the HEV radiator 64, and a motor inlet pipe 72.

[0036] The motor 61 is a vehicle driving motor for driving the hybrid vehicle 100. The motor 61 has a coolant flow passage 61a through which coolant flows. The PCU 62 converts DC power supplied from a battery (not shown) into AC power and supplies it to the motor 61, and when the motor 61 functions as a generator, converts AC power generated by the motor 61 into DC power to charge the battery. The PCU 62 has a coolant flow passage 62a through which coolant flows. The coolant flow passage 62a of the PCU 62 is connected to the coolant flow passage 61a of the motor 61 by a motor outlet pipe 73. The HEV radiator 64 has a coolant flow passage 64a through which coolant flows, and exchanges heat with the outside air flowing outside to cool the high-temperature coolant. The HEV radiator 64 is attached to the radiator support 25 upstream of the radiator 16 in series with the radiator 16 in the direction of flow of the outside air and in parallel with the condenser 42. Cooling fan 17 also blows cooling air to HEV radiator 64. An inlet of coolant flow path 64a of HEV radiator 64 is connected to a discharge port of coolant pump 63 by coolant pump outlet pipe 71. In addition, an outlet of coolant flow path 64a of HEV radiator 64 is connected to coolant flow path 61a of motor 61 by motor inlet pipe 72. Motor cooling circuit 70 circulates coolant to motor 61, PCU 62, and HEV radiator 64 by coolant pump 63, and dissipates heat generated by motor 61 and PCU 62 by HEV radiator 64 to cool motor 61 and PCU 62.

[0037] The outside air temperature sensor 57 detects the outside air temperature of the hybrid vehicle 100. The outside air temperature sensor 57 may be provided in the vicinity of the outside air inlet of the radiator support 25, for example.

[0038] The control unit 80 is a computer having a CPU 81, which is a processor for performing information processing, and a memory 82 for storing operation programs, operation data, and the like. The engine 11, the three-way flow control valve 20, the electric pump 14, the water heater 15, the compressor 41, the expansion valve 43, the indoor fan 45, the switching damper 46, the motor 61, the PCU 62, and the coolant pump 63 are connected to the control unit 80 and operate according to commands from the control unit 80. The high pressure of the cooler detected by the pressure sensor 55, the refrigerant temperature at the evaporator outlet detected by the temperature sensor 56, and the outside air temperature detected by the outside air temperature sensor 57 are input to the control unit 80. The operation of the control unit 80 is realized by the CPU 81 executing the control program stored in the memory 82.

[0039] The memory 82 of the control unit 80 stores control maps 83 to 85 shown in Figs. 2 to 4. As shown in Fig. 2, the control map 83 is a map that specifies the relationship between the set value of the refrigerant temperature at the outlet of the evaporator 44 and the cooler high pressure detected by the pressure sensor 55. In Fig. 2, the first pressure PS1 is a predetermined set pressure at which the condenser heat radiation amount reduction process described later is started. The engine start pressure PE is a set pressure at which the engine 11 is started by the rise in the cooler high pressure and the vehicle moves to running in the HV mode. The second pressure PS2 is a pressure that is higher than the first pressure PS1 and slightly lower than the engine start pressure PE, and is a predetermined set pressure at which the reduction in the air volume of the indoor fan 45 is started. The control map 83 is a map that increases the set value of the refrigerant temperature at the outlet of the evaporator 44 from the normal set temperature TS1 when the cooler high pressure becomes equal to or higher than the first pressure, and sets the set value of the refrigerant temperature at the outlet of the evaporator 44 to TS2, which is higher than TS1, when the cooler high pressure becomes equal to or higher than the second pressure PS2.

[0040] 3 is a map that specifies the relationship between the cooler high pressure and the upper limit rotation speed of the compressor 41. The control map 84 is a map in which, when the cooler high pressure becomes equal to or higher than a first pressure, the upper limit rotation speed of the compressor 41 is reduced from the normal upper limit rotation speed R0, and when the cooler high pressure becomes equal to or higher than a second pressure PS2, the upper limit rotation speed of the compressor 41 is set to R1.

[0041] 4 is a map that specifies the relationship between the air volume of the indoor fan 45 and the refrigerant temperature at the outlet of the evaporator 44 detected by the temperature sensor 56. The control map 85 is a map in which, when the refrigerant temperature at the outlet of the evaporator 44 becomes equal to or higher than TS1, the air volume of the indoor fan 45 is reduced from the normal setting Q0, and, when the refrigerant temperature at the outlet of the evaporator 44 becomes equal to or higher than TS3, the air volume of the indoor fan 45 is set to Q1.

[0042] Next, control of the air conditioner 200 while the hybrid vehicle 100 is running in the EV mode while cooling the passenger compartment with the air conditioner 200 will be described with reference to Fig. 5. When the hybrid vehicle 100 is running in the EV mode, the engine 11 is stopped, so that no coolant flows through the engine cooling circuit 30, and the cooling fan 17 driven by the engine 11 is stopped. On the other hand, the motor 61 is running, so that the coolant pump 63 circulates the coolant to the motor 61, the PCU 62, and the HEV radiator 64 as shown by the arrows in Fig. 1, thereby cooling the motor 61 and the PCU 62. In addition, since the passenger compartment is being cooled, the compressor 41 operates to circulate the refrigerant as shown by the arrows in Fig. 1, and heat is dissipated to the outside air from the condenser 42.

[0043] The control unit 80 determines whether the hybrid vehicle 100 is running in the EV mode as shown in step 101 of Fig. 5. If the control unit 80 determines NO in step 101 of Fig. 5, the control unit 80 waits while repeatedly executing step 101 of Fig. 5.

[0044] If the control unit 80 judges YES in step 101 of Fig. 5, it proceeds to step 102 of Fig. 5 to judge whether the cooler high pressure detected by the pressure sensor 55 is equal to or higher than the first pressure PS1. If the control unit 80 judges NO in step 102 of Fig. 5, it returns to step 101 of Fig. 5 and waits while repeatedly executing Figs. 101 and 102. On the other hand, if the control unit 80 judges YES in step 102 of Fig. 5, it proceeds to step 103 of Fig. 5. Here, the first pressure PS1 is a predetermined set pressure at which the condenser heat radiation amount reduction process is started, and can be set freely, but may be set to, for example, about 70 to 80% of the engine start pressure PE.

[0045] 5, the control unit 80 determines whether the outside air temperature detected by the outside air temperature sensor 57 is lower than a first temperature Tout1. The first temperature Tout1 is a temperature at which the outside air temperature is high and it is necessary to start the engine 11 and increase the amount of heat dissipated from the condenser 42 to give priority to cooling the passenger compartment. The first temperature Tout1 can be set freely, but may be set to, for example, about 40°C to 45°C.

[0046] If the control unit 80 determines YES in step 103 of FIG. 5, that is, if the outside air temperature is not high enough to prioritize cooling of the passenger compartment, the control unit 80 proceeds to step 104 of FIG. 5, performs a condenser heat dissipation reduction process that will be described later, continues EV driving, and proceeds to step 105 of FIG. 5.

[0047] The control unit 80 determines whether the cooler high pressure is equal to or higher than the engine start pressure PE in step 105 of Fig. 5. As described above, the engine start pressure PE is the pressure at which an increase in the cooler high pressure requires starting the engine 11, transitioning to running in HV mode, and increasing the amount of heat dissipated by the condenser 42.

[0048] If the control unit 80 determines NO in step 105 in Fig. 5, it returns to step 101 in Fig. 5 and repeats steps 101 to 105. At this time, the control unit 80 continues EV running with the engine 11 stopped.

[0049] On the other hand, if the control unit 80 determines YES in step 105 of Fig. 5, the process proceeds to step 106 of Fig. 5, where the engine 11 is started and the driving mode is changed from EV mode to HV mode, and the condenser heat dissipation amount reduction process is stopped in step 107 of Fig. 5. When the engine 11 is started, the cooling fan 17 operates and the amount of outside air passing through the condenser 42 increases. This increases the amount of heat dissipated by the condenser 42, making it possible to reduce the high cooler pressure.

[0050] Furthermore, if the control unit 80 judges NO in step 103 of FIG. 5, that is, if the outside air temperature is equal to or higher than the first temperature Tout1, the control unit 80 proceeds to step 106 of FIG. 5, starts the engine 11, switches the driving mode to the HV mode, and stops the condenser heat dissipation reduction process in step 107 of FIG. 5.

[0051] Next, the condenser heat radiation amount reduction process in step 104 in FIG. 5 will be described with reference to FIG.

[0052] As shown in step 201 of Fig. 6, the control unit 80 determines whether the switching damper 46 has been switched to the inside air recirculation. If the control unit 80 determines YES in step 201 of Fig. 6, the control unit 80 proceeds to step 203 of Fig. 6. On the other hand, if the control unit 80 determines NO in step 201 of Fig. 6, the control unit 80 proceeds to step 202 of Fig. 6 to switch the switching damper 46 to the inside air recirculation, and proceeds to step 203 of Fig. 2.

[0053] The control unit 80 increases the duty of the indoor fan 45 in step 203 of Fig. 6. The duty may be increased to a level at which the noise of the fan is not bothersome to the passengers, or may be increased to the maximum duty.

[0054] In this way, by increasing the duty of the indoor fan 45 to circulate the internal air and increasing the flow rate of air circulating inside the vehicle cabin, the temperature inside the vehicle can be kept low, and the amount of heat dissipated by the condenser 42 can be reduced without compromising the comfort of the occupants, thereby suppressing an increase in high cooler pressure.

[0055] Next, the control unit 80 proceeds to step 204 in Fig. 6, and applies the control map 83 shown in Fig. 2 to increase the set value of the refrigerant temperature at the outlet of the evaporator 44 as the cooler high pressure increases. This reduces the amount of heat exchanged between the evaporator 44 and the air blown into the vehicle cabin, reducing the load on the air conditioner 200. This reduces the amount of heat dissipated from the condenser 42 to the outside air, allowing the cooler high pressure to be lowered.

[0056] 3, the control unit 80 reduces the upper limit rotation speed of the compressor 41 as the cooler high pressure increases. This reduces the pressure of the refrigerant at the outlet of the compressor 41, and reduces the cooler high pressure.

[0057] Then, the control unit 80 proceeds to step 205 in FIG. 6 to determine whether the cooler high pressure detected by the pressure sensor 55 is equal to or higher than the second pressure PS2. Here, the second pressure PS2 is a pressure slightly lower than the engine start pressure PE. That is, if the cooler pressure has risen to just before the engine start pressure PE even after the processes of steps 201 to 204 in FIG. 6 are performed, the control unit 80 judges YES in step 205 in FIG. 6 and proceeds to step 206 in FIG. 6. Then, in step 206 in FIG. 6, the control unit 80 applies the control map 85 shown in FIG. 4 to reduce the duty of the indoor fan 45 as the refrigerant temperature at the outlet of the evaporator 44 increases, thereby reducing the air volume of the indoor fan 45. This further reduces the amount of heat exchanged between the evaporator 44 and the air blown into the vehicle cabin, thereby reducing the load on the air conditioner 200. This reduces the amount of heat dissipated from the condenser 42 to the outside air, thereby allowing the cooler high pressure to be further reduced.

[0058] On the other hand, if the control unit 80 determines NO in step 205 in FIG. 6, it ends the evaporator heat radiation amount reduction process without performing the process of step 206 in FIG.

[0059] As described above, the hybrid vehicle 100 of the embodiment reduces the amount of heat dissipation from the condenser 42 during EV driving, thereby suppressing an increase in the cooler high pressure during EV driving and enabling EV driving to be continued. Also, when the outside temperature is high and cooling is required, the hybrid vehicle 100 of the embodiment starts the engine 11 to increase the amount of heat dissipation from the condenser 42, enabling sufficient cooling.

[0060] In addition, the hybrid vehicle 100 of the embodiment improves the efficiency of the refrigeration cycle and reduces the amount of heat dissipated by the condenser 42 by circulating the air flowing into the vehicle cabin and increasing the duty of the indoor fan 45. This makes it possible to reduce the amount of heat dissipated by the condenser 42 without impairing the comfort of the passengers.

[0061] In addition, in the hybrid vehicle 100 of the embodiment, as the cooler high pressure increases, the set value of the refrigerant temperature at the outlet of the evaporator 44 is increased and the upper limit rotation speed of the compressor 41 is reduced. This reduces the cooling load of the air conditioner 200 and reduces the amount of heat radiation from the condenser 42.

[0062] Furthermore, in the hybrid vehicle 100 of the embodiment, when the cooler high pressure is higher than the second pressure PS2 just before the engine start pressure PE even after improving the efficiency of the refrigeration cycle and reducing the load on the air conditioning device 200, the duty of the indoor fan 45 is reduced to further reduce the load on the air conditioning device 200, thereby more effectively suppressing the rise in the cooler high pressure and enabling driving in EV mode to be continued. [Explanation of symbols]

[0063] 11 engine, 11a, 13a, 15a, 16a cooling water flow path, 12 engine driven pump, 13 heater core, 14 electric pump, 15 water heater, 16 radiator, 17 cooling fan, 18 thermostat, 19 flow path switching damper, 20 three-way flow control valve, 25 radiator support, 30 engine cooling circuit, 31 engine outlet pipe, 32 heater core inlet pipe, 33 heater core outlet pipe, 34 engine bypass pipe, 35 water heater outlet pipe, 36 radiator inlet pipe, 37 radiator outlet pipe, 38 radiator bypass pipe, 39 engine driven pump inlet pipe, 41 compressor, 42 condenser, 42a, 44a refrigerant flow path, 43 expansion valve, 44 evaporator, 45 indoor fan, 46 switching damper, 47 blowing duct, 50 refrigeration cycle circuit, 51 Compressor outlet pipe, 52 condenser outlet pipe, 53 evaporator inlet pipe, 54 evaporator outlet pipe, 55 pressure sensor, 56 temperature sensor, 57 outside air temperature sensor, 61 motor, 62 PCU, 61a, 62a, 64a coolant flow path, 63 coolant pump, 64 HEV radiator, 70 motor cooling circuit, 71 coolant pump outlet pipe, 72 motor inlet pipe, 73 motor outlet pipe, 74 PCU outlet pipe, 80 control unit, 81 CPU, 82 memory, 83, 84, 85 control map, 100 hybrid vehicle, 200 air conditioning unit.

Claims

1. A hybrid vehicle capable of running in an HV mode in which the vehicle is driven by an engine and a motor for driving the vehicle, and an EV mode in which the engine is stopped and the vehicle is driven by the motor, A radiator for cooling the cooling water circulating inside the engine; an air conditioning device for conditioning air in a vehicle cabin, the air conditioning device including a compressor, a condenser for condensing the refrigerant compressed by the compressor, and a pressure sensor for detecting a pressure of the refrigerant compressed by the compressor; a cooling fan that operates in response to the rotation of the engine to blow cooling air to the radiator and the condenser; A control unit that controls the engine and the operation of the air conditioning device, the control unit reduces an amount of heat dissipation from the condenser when a pressure of the refrigerant detected by the pressure sensor during traveling in the EV mode becomes equal to or higher than a predetermined first pressure; A hybrid vehicle characterized by:

2. 2. The hybrid vehicle according to claim 1, When the pressure of the refrigerant detected by the pressure sensor during driving in the EV mode is equal to or higher than the first pressure and the outside air temperature is lower than a predetermined first temperature, the control unit maintains the driving mode in the EV mode and reduces the amount of heat dissipated by the condenser, When the pressure of the refrigerant detected by the pressure sensor during driving in the EV mode is equal to or higher than the first pressure and the outside air temperature is equal to or higher than the first temperature, the engine is started and the driving mode is switched from the EV mode to the HV mode, and the amount of heat dissipated by the condenser is not reduced. A hybrid vehicle characterized by:

3. 3. The hybrid vehicle according to claim 2, the air conditioner includes an indoor fan that blows air into a vehicle cabin, and a switching damper that switches between an outside air introduction mode that introduces outside air into the vehicle cabin and an inside air circulation mode that circulates air within the vehicle cabin; the control unit switches the switching damper to the inside air circulation mode and increases the duty of the indoor fan to reduce the amount of heat dissipated by the condenser; A hybrid vehicle characterized by:

4. 4. The hybrid vehicle according to claim 3, The air conditioner includes an evaporator through which a refrigerant flows to cool air to be blown into a vehicle compartment, the control unit increases a set value of a refrigerant temperature at an outlet of an evaporator as the pressure of the refrigerant detected by the pressure sensor increases, and reduces an upper limit rotation speed of the compressor, thereby reducing an amount of heat radiation from the condenser; A hybrid vehicle characterized by:

5. A hybrid vehicle according to claim 4, the control unit reduces a duty of the indoor fan as the refrigerant temperature at the evaporator outlet increases when the pressure of the refrigerant detected by the pressure sensor is higher than the first pressure and equal to or higher than a second pressure lower than an engine start pressure, thereby reducing an amount of heat dissipated by the condenser; A hybrid vehicle characterized by:

Images