JP7816239B2 - Battery temperature control system and hybrid vehicle - Google Patents

Description

The present invention relates to a battery temperature regulation system and hybrid vehicle configuration that warms up the engine using waste heat from the battery.

In recent years, electric vehicles powered by a motor have become increasingly common. These vehicles are equipped with a battery that supplies driving power to the motor. Because batteries generate heat when they are charged and discharged, electric vehicles are equipped with a cooling circuit to cool the battery. The battery cooling circuit releases the heat generated by the battery to the outside as waste heat. Meanwhile, improved fuel economy is also required in electric vehicles. To address this issue, a system has been proposed that uses waste heat from the battery to heat a second refrigerant in the battery cooling circuit, and then transfers the heat of the second refrigerant via a heat exchanger to a first refrigerant in an air conditioning circuit that heats the passenger compartment, thereby heating the passenger compartment (see, for example, Patent Document 1).

A system has also been proposed in which the refrigerant in the air conditioning circuit is heated by coolant that has been heated by flowing through a battery, thereby heating the passenger compartment (see, for example, Patent Document 2).

JP 2023-11132 A Japanese Patent Application Laid-Open No. 2020-34228

Hybrid vehicles have traditionally been capable of running in two modes: HV mode, in which the vehicle is powered by an engine and a vehicle-driving motor, and EV mode, in which the engine is stopped and the vehicle is powered by the motor. In recent years, such hybrid vehicles have been traveling longer distances in EV mode, and there are cases where the engine is not started and the vehicle is powered solely by the motor for long periods of time. When switching from EV mode to HV mode after running solely on the motor for a long period of time, it is necessary to warm up the engine in a short period of time.

The present disclosure therefore aims to shorten the engine warm-up time in hybrid vehicles.

The battery temperature regulation system of the present disclosure is a battery temperature regulation system mounted on a hybrid vehicle capable of running in an HV mode in which the vehicle runs using an engine and a motor for driving the vehicle, and an EV mode in which the engine is stopped and the vehicle runs using the motor, and includes an engine coolant circuit that circulates coolant through the engine, the engine coolant circuit including a heater core that exchanges heat with the coolant to heat air to be blown into the vehicle compartment, and a water heater that is provided downstream of the heater core and heats the coolant , a battery temperature regulation circuit that circulates a liquid heat medium through a battery that supplies power to the motor to cool or heat the battery, and a battery temperature regulation circuit that is connected to the engine coolant circuit so as to bypass the heater core and that is connected to the battery a heat exchange circuit provided with a water-water heat exchanger arranged across a temperature control circuit and performing heat exchange between the coolant and the heat medium ; an engine bypass circuit connecting a downstream side of the water heater and an upstream side of the heater core so as to bypass the engine; a four-way flow control valve provided between the engine and the heater core in the engine coolant circuit, connecting the heat exchange circuit and the engine bypass circuit, and adjusting the flow rate of the coolant between the heater core, the water-water heat exchanger, and the engine; an electric pump provided between the heater core and the water heater in the engine coolant circuit; and a control unit adjusting operations of the four-way flow control valve and the electric pump , a first port connected to a coolant inlet of the heater core, a second port connected to a coolant inlet of the water-water heat exchanger, a third port connected to a coolant outlet of the water heating heater, and when the hybrid vehicle shifts from the EV mode to the HV mode, and the temperature of the battery is equal to or higher than a predetermined value and the temperature of the engine coolant is lower than the temperature of the battery, the control unit opens the first port and the third port of the four-way flow control valve, closes the fourth port, and opens or closes the second port so that the engine coolant circuit and the heat exchange circuit communicate with each other, thereby causing the coolant to flow through the water-water heat exchanger and changing the temperature of the engine coolant. and when the hybrid vehicle is in the EV mode and there is a request for heating the passenger compartment, the temperature of the battery is equal to or higher than a predetermined value, and the temperature of the coolant in the heater core is lower than the temperature of the battery, the engine coolant circuit, the engine bypass circuit, and the heat exchange circuit are connected to each other, the first port of the four-way flow control valve is closed and the second port, the third port, and the fourth port are opened so that the coolant does not flow to the engine, the electric pump is operated, and the coolant is caused to flow through the water-water heat exchanger and the heater core, thereby increasing the temperature of the coolant in the heater core and decreasing the temperature of the heat medium .

In this way, the engine coolant temperature is raised using the battery's exhaust heat, thereby shortening the engine warm-up time and effectively utilizing the battery's exhaust heat to improve fuel economy. Furthermore, the four-way flow control valve adjusts the flow rate of the coolant between the heater core, the water-water heat exchanger, and the engine, so the engine warm-up time can be shortened by raising the engine coolant temperature using the battery's exhaust heat with a simple configuration. Furthermore, when the hybrid vehicle is running in EV mode, the vehicle interior is heated using the battery's exhaust heat, thereby improving fuel economy.

In the battery temperature adjustment system of the present disclosure, when the hybrid vehicle transitions from the EV mode to the HV mode, the temperature of the battery is higher than a predetermined value, and the temperature of the engine coolant is lower than the temperature of the battery , the control unit may open the second port if there is a request to heat the passenger compartment, and close the second port if there is no request to heat the passenger compartment.

The hybrid vehicle of the present disclosure is a hybrid vehicle that can run in an HV mode in which it runs using an engine and a motor for driving the vehicle, and an EV mode in which it runs using the motor with the engine stopped, and includes an engine coolant circuit that circulates coolant through the engine, the engine coolant circuit including a heater core that exchanges heat with the coolant to heat air to be blown into the vehicle compartment, and a water heater that is provided downstream of the heater core and heats the coolant; a battery temperature adjustment circuit that circulates a liquid heat medium through a battery that supplies power to the motor to cool or heat the battery; and a battery temperature adjustment circuit that is connected to the engine coolant circuit so as to bypass the heater core and is provided across the battery temperature adjustment circuit. a heat exchange circuit in which a water-water heat exchanger that exchanges heat between the coolant and the heat medium is provided, an engine bypass circuit that connects a downstream side of the water heater with an upstream side of the heater core so as to bypass the engine, a four-way flow control valve that is provided between the engine and the heater core in the engine coolant circuit and connects the heat exchange circuit with the engine bypass circuit and adjusts the flow rate of the coolant between the heater core, the water-water heat exchanger, and the engine, an electric pump that is provided between the heater core and the water heater in the engine coolant circuit, and a control unit that adjusts operation of the four-way flow control valve and the electric pump , and a fourth port connected to a coolant outlet of the water-water heat exchanger, and when the traveling mode is shifted from the EV mode to the HV mode, if the temperature of the battery is equal to or higher than a predetermined value and the temperature of the engine coolant is lower than the temperature of the battery, the control unit opens the first port and the third port of the four-way flow control valve, closes the fourth port, and opens or closes the second port so that the engine coolant circuit and the heat exchange circuit communicate with each other, thereby causing the coolant to flow through the water-water heat exchanger and increasing the temperature of the engine coolant. and when the driving mode is the EV mode and there is a request for heating the vehicle compartment, the temperature of the battery is equal to or higher than a predetermined value, and the temperature of the coolant in the heater core is lower than the temperature of the battery, the engine coolant circuit, the engine bypass circuit, and the heat exchange circuit are communicated with each other, and the first port of the four-way flow control valve is closed and the second port, the third port, and the fourth port are opened so that the coolant does not flow to the engine, the electric pump is operated, and the coolant is caused to flow through the water-water heat exchanger and the heater core, thereby increasing the temperature of the coolant in the heater core and decreasing the temperature of the heat medium .

In the hybrid vehicle of the present disclosure, when the driving mode transitions from the EV mode to the HV mode, if the temperature of the battery is higher than a predetermined value and the temperature of the engine coolant is lower than the temperature of the battery, the control unit may open the second port if there is a request to heat the passenger compartment, and close the second port if there is no request to heat the passenger compartment.

This disclosure can shorten the engine warm-up time in hybrid vehicles.

1 is a system diagram showing the configuration of a battery temperature regulation system and a hybrid vehicle according to an embodiment; FIG. 2 is a system diagram showing a state in which the first port of the four-way flow control valve of the battery temperature regulation system shown in FIG. 1 is closed and the vehicle is running in EV mode, and coolant is circulated through a part of the engine coolant circuit, the heat exchange circuit, and the engine bypass circuit. This is a system diagram showing a state in which, when the temperature of the engine coolant is low, the fourth port of the four-way flow control valve of the battery temperature regulation system shown in Figure 1 is closed and the first to third ports are opened, causing the coolant to circulate through the engine coolant circuit and the heat exchange circuit. This is a system diagram showing a state in which, when the temperature of the engine coolant is low, the fourth and second ports of the four-way flow control valve of the battery temperature regulation system shown in Figure 1 are closed, and the first and third ports are opened, causing the coolant to circulate through part of the engine coolant circuit and the heat exchange circuit. 2 is a flowchart showing the operation of the battery temperature regulation system shown in FIG. 1 . 6 is a flowchart continuing from the flowchart shown in FIG. 5 .

The battery temperature regulation system 100 according to an embodiment will now be described with reference to the drawings. As shown in FIG. 1, the battery temperature regulation system 100 is installed in a hybrid vehicle 200 that can run in two modes: an HV mode, in which the vehicle is powered by the engine 11 and the vehicle drive motor 19, and an EV mode, in which the engine 11 is stopped and the vehicle is powered by the motor 19. The hybrid vehicle 200 is equipped with a battery 51. The battery 51 is connected to the motor 19 by two high-voltage cables 58, 59 and supplies power to the vehicle drive motor 19. A voltage sensor 66 that detects the voltage of the battery 51 is attached between the high-voltage cables 58, 59. A current sensor 65 that detects the charge/discharge current of the battery 51 is also attached to the high-voltage cable 58. The hybrid vehicle 200 is also equipped with an air conditioning panel 25 that regulates the temperature of the vehicle interior.

The hybrid vehicle 200 is connected to the engine 11 and motor 19 and is equipped with a vehicle control unit 80 that adjusts the operation of the engine 11 and motor 19. The vehicle control unit 80 is a computer that includes a CPU 81 that processes information and a memory 82 that stores control programs and control data. Current and voltage data detected by the current sensor 65 and voltage sensor 66 are input to the vehicle control unit 80. The vehicle control unit 80 is also connected to an air conditioning panel 25. The air conditioning panel 25 inputs air conditioning status information, such as whether the heating and cooling functions for the passenger compartment are on or off, to the vehicle control unit 80. The vehicle control unit 80 outputs driving mode information, indicating whether the hybrid vehicle 200 is running in HV mode or EV mode, and air conditioning status information.

As shown in FIG. 1, the battery temperature regulation system 100 includes an engine coolant circuit 30 that circulates coolant through the engine 11, a battery temperature regulation circuit 50 that circulates a liquid heat medium through the battery 51 to cool or heat the battery 51, a heat exchange circuit 40, an engine bypass circuit 45, and a control unit 70. In the following description, the liquid heat medium will be described as battery coolant, but other fluids may also be used.

First, we will explain the engine coolant circuit 30. The engine coolant circuit 30 includes, in series from the upstream side, the engine 11, four-way flow control valve 20, heater core 13, electric pump 14, water heater 15, thermostat 17, and radiator 16. The engine coolant circuit 30 is a flow path that passes coolant through each of these devices.

The engine 11 is the driving source of the hybrid vehicle 200. The engine 11 has a coolant flow path 11a through which coolant flows. The engine 11 is also equipped 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 coolant flow path 11a. The four-way flow control valve 20 is provided in the engine coolant circuit 30 between the engine 11 and the heater core 13. The four-way flow control valve 20 has four ports: a first port 21, a second port 22, a third port 23, and a fourth port 24. The four-way flow control valve 20 can switch the coolant flow path by opening or closing these four ports. The four-way flow control valve 20 is a switching valve that switches between closed and open communication between the engine coolant circuit 30 and the heat exchange circuit 40. The four-way flow control valve 20 can also adjust the flow rate of the cooling water flowing out from the second port 22 and the third port 23. The operation of the four-way flow control valve 20 will be explained in detail later with reference to Figures 2 to 4.

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 engine 11's coolant flow path 11a flows and heats the air blown into the vehicle cabin. The electric pump 14 is driven by a motor (not shown) and circulates the coolant between the engine coolant circuit 30 and the heat exchange circuit 40. The water heater 15 heats the coolant that flows through the heater core 13 when the hybrid vehicle 200 is running in EV mode. In other words, the water heater 15 is a heat source that heats the vehicle cabin when the hybrid vehicle 200 is running in EV mode. The water heater 15 includes a coolant flow path 15a through which the coolant flows. The thermostat 17 is a switching valve that switches the flow of coolant to the radiator bypass pipe 38 when the coolant temperature is low and to the radiator 16 when the coolant temperature is high. The radiator 16 is a heat exchanger that cools the coolant using outside air. The radiator 16 has a coolant flow path 16a through which the coolant flows.

Next, the configuration of the engine coolant circuit 30 will be described. The engine coolant circuit 30 is composed of the engine-driven pump 12, the coolant flow path 11a of the engine 11, the engine outlet pipe 31, the four-way flow control valve 20, the heater core inlet pipe 32, the coolant flow path 13a of the heater core 13, the heater core outlet pipe 33, the electric pump 14, the electric pump outlet pipe 34, the coolant flow path 15a of the water heater 15, the water heater outlet pipe 35, the thermostat 17, the radiator inlet pipe 36, the coolant flow path 16a of the radiator 16, the radiator outlet pipe 37, the engine-driven pump inlet pipe 39, and the radiator bypass pipe 38.

The engine outlet pipe 31 connects the outlet of the coolant flow path 11a of the engine 11 to the first port 21 of the four-way flow control valve 20. The heater core inlet pipe 32 connects the second port 22 of the four-way flow control valve 20 to the inlet of the coolant flow path 13a of the heater core 13. The heater core outlet pipe 33 connects the outlet of the coolant flow path 13a of the heater core 13 to the suction port of the electric pump 14. The electric pump outlet pipe 34 connects the discharge port of the electric pump 14 to the inlet of the coolant flow path 15a of the water heater 15. The water heater outlet pipe 35 connects the outlet of the coolant flow path 15a of the water heater 15 to the thermostat 17. The radiator inlet pipe 36 connects the thermostat 17 to the inlet of the coolant flow path 16a of the radiator 16. The radiator outlet pipe 37 connects the outlet of the cooling water flow path 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 bypasses the radiator 16 and connects the thermostat 17 to the engine-driven pump inlet pipe 39.

The engine outlet pipe 31 is provided with an engine coolant temperature sensor 61 that detects the temperature of the coolant at the outlet of the engine 11. The water heater outlet pipe 35 is provided with a water heater coolant temperature sensor 62 that detects the temperature of the coolant at the outlet of the water heater 15. The heater core outlet pipe 33 is provided with a heater core coolant temperature sensor 67 that detects the temperature of the coolant at the outlet of the heater core 13.

Next, the heat exchange circuit 40 will be described. The heat exchange circuit 40 is connected to the engine coolant circuit 30 so as to bypass the heater core 13. The heat exchange circuit 40 is a flow path connecting the third port 23 of the four-way flow control valve 20 and the heater core outlet pipe 33. The heat exchange circuit 40 is provided with a water-water heat exchanger 18 that is disposed across the heat exchange circuit 40 and the battery temperature control circuit 50 and performs heat exchange between the coolant and the battery coolant. The water-water heat exchanger 18 has a coolant flow path 18a through which the coolant flows and a battery coolant flow path 18b through which the battery coolant flows. The third port 23 of the four-way flow control valve 20 is connected to the inlet of the coolant flow path 18a of the water-water heat exchanger 18 by a heat exchanger inlet pipe 41. The outlet of the coolant flow path 18a of the water-water heat exchanger 18 is connected to the heater core outlet pipe 33 by a heat exchanger outlet pipe 42.

Next, we will explain the engine bypass circuit 45. The engine bypass circuit 45 is a flow path that connects the water heater outlet pipe 35 of the engine coolant circuit 30 to the fourth port 24 of the four-way flow control valve 20 so as to bypass the engine 11.

Next, we will explain the battery temperature regulation circuit 50. The battery temperature regulation circuit 50 is equipped with a battery cooling water pump 52, a chiller 53, a battery 51, and a water-water heat exchanger 18, arranged in series from the upstream side. The battery temperature regulation circuit 50 is a flow path that passes battery cooling water, which is a liquid heat medium, through each of these devices.

The battery cooling water pump 52 circulates the battery cooling water through the battery temperature regulation circuit 50. The chiller 53 has a battery cooling water flow path 53a through which the battery cooling water flows, and a refrigerant flow path 53b connected to an air conditioning unit (not shown) through which a refrigerant flows. The chiller 53 is a heat exchanger that exchanges heat between the battery cooling water and the refrigerant, cooling or heating the battery cooling water with the refrigerant. The battery 51 has a battery cooling water flow path 51a through which the battery cooling water flows.

The battery temperature adjustment circuit 50 is composed of a battery cooling water pump 52, a battery cooling water flow path 53a of the chiller 53, a chiller inlet pipe 54, a chiller outlet pipe 55, a battery cooling water flow path 51a of the battery 51, a battery outlet pipe 56, a battery cooling water flow path 18b of the water-to-water heat exchanger 18, and a heat exchanger outlet pipe 57.

The chiller inlet pipe 54 connects the discharge of the battery cooling water pump 52 to the inlet of the battery cooling water flow path 53a of the chiller 53. The chiller outlet pipe 55 connects the outlet of the battery cooling water flow path 53a of the chiller 53 to the inlet of the battery cooling water flow path 51a of the battery 51. The battery outlet pipe 56 connects the outlet of the battery cooling water flow path 51a of the battery 51 to the inlet of the battery cooling water flow path 18b of the water-water heat exchanger 18. The heat exchanger outlet pipe 57 connects the outlet of the battery cooling water flow path 18b of the water-water heat exchanger 18 to the suction port of the battery cooling water pump 52.

A battery coolant temperature sensor 63 is provided in the battery outlet pipe 56 to detect the temperature of the battery coolant at the outlet of the battery 51. In addition, a battery temperature sensor 64 is provided in the battery 51 to detect the temperature of the battery 51.

The control unit 70 is a computer equipped with an internal CPU 71 for information processing and memory 72 for storing control programs and control data. The four-way flow control valve 20, electric pump 14, water heater 15, and battery coolant pump 52 are connected to the control unit 70. The engine coolant temperature sensor 61, water heater coolant temperature sensor 62, heater core coolant temperature sensor 67, battery coolant temperature sensor 63, and battery temperature sensor 64 are also connected to the control unit 70, and the temperature data detected by each sensor is input to the control unit 70. The control unit 70 adjusts the operation of the four-way flow control valve 20, electric pump 14, water heater 15, and battery coolant pump 52 based on the data input from each sensor.

The control unit 70 is also connected to the vehicle control unit 80 to exchange data. The control unit 70 receives driving mode information and air conditioning status information from the vehicle control unit 80. As explained above, the driving mode information includes information on whether the hybrid vehicle 200 is running in HV mode or EV mode. The air conditioning status information includes information on whether the heating and cooling of the passenger compartment is on or off.

Next, the operation of the four-way flow control valve 20 and the flow of coolant and battery coolant will be explained with reference to Figures 2 to 4. In Figures 2 to 4, the thick arrows and thick dashed-dotted arrows indicate a state in which coolant is flowing. The thick dashed lines indicate a state in which battery coolant is flowing, and the thick two-dot chain arrows indicate a state in which refrigerant is flowing. The thin dashed lines indicate a state in which coolant is not flowing.

First, with reference to Figure 2, we will explain the flow path configuration when the hybrid vehicle 200 is running in EV mode and the exhaust heat from the battery 51 is used to heat the vehicle interior and cool the battery 51.

When the hybrid vehicle 200 runs in EV mode with the engine 11 stopped, there is no need to circulate coolant through the engine 11. Therefore, as shown in FIG. 2, the control unit 70 closes the first port 21 of the four-way flow control valve 20 and opens the fourth port 24, the second port 22, and the third port 23. As a result, as indicated by the thin dashed lines in FIG. 2, coolant does not flow through the engine 11. At this time, the engine-driven pump 12 is stopped along with the engine 11. To heat the passenger compartment, the electric pump 14 and water heater 15 are operating. The coolant pressurized by the electric pump 14 flows through the coolant flow path 15a of the water heater 15, as indicated by the thick arrow in FIG. 2, and becomes high-temperature coolant. The high-temperature coolant then flows through the engine bypass circuit 45 into the four-way flow control valve 20. A portion of the coolant passes from the second port 22 through the coolant flow path 13a of the heater core 13, exchanges heat with the low-temperature air blown into the vehicle cabin, and becomes low-temperature coolant, which is then returned to the electric pump 14. Another portion of the coolant passes through the water-to-water heat exchanger 18 and returns to the electric pump 14.

When the hybrid vehicle 200 runs in EV mode with the engine 11 stopped, the temperature of the battery 51 increases due to discharging to the motor 19. When the temperature of the battery 51 is high, as shown by the thick dashed arrow in FIG. 2 , the battery coolant pressurized by the battery coolant pump 52 flows through the battery coolant flow path 53a of the chiller 53, and as shown by the thick dashed-line arrow in FIG. 2 , exchanges heat with the low-temperature refrigerant of the air conditioner flowing through the refrigerant flow path 53b of the chiller 53, becoming low-temperature battery coolant. As shown by the thick dashed-line arrow in FIG. 2 , the low-temperature battery coolant flows into the battery coolant flow path 51a of the battery 51 to cool the battery 51. Then, the battery coolant, whose temperature has increased by flowing through the battery coolant flow path 51a of the battery 51, flows through the battery coolant flow path 18b of the water-water heat exchanger 18 and returns to the battery coolant pump 52.

In this way, the battery coolant flow path 18b of the water-water heat exchanger 18 receives battery coolant whose temperature has increased after flowing through the battery coolant flow path 51a of the battery 51. If the temperature of the remaining battery coolant flowing through the coolant flow path 18a of the water-water heat exchanger 18 is lower than the temperature of the battery coolant at the outlet of the battery coolant flow path 51a, the remaining battery coolant exchanges heat with the higher-temperature battery coolant flowing through the battery coolant flow path 18b, resulting in higher-temperature battery coolant. The remaining battery coolant, now at a higher temperature, flows from the coolant flow path 18a of the water-water heat exchanger 18 into the heater core outlet pipe 33 through the heat exchanger outlet pipe 42. The remaining battery coolant, along with the remaining battery coolant that flowed through the heater core 13's coolant flow path 13a, is returned to the electric pump 14. This increases the temperature of the battery coolant flowing through the heater core 13. When the temperature of the coolant rises due to the heat emitted from the battery 51, the control unit 70 reduces the amount of heat heated by the water heater 15. Meanwhile, the temperature of the battery coolant at the outlet of the battery coolant flow path 18b of the water-water heat exchanger 18 drops below the temperature of the battery coolant at the inlet of the battery coolant flow path 18b.

In this way, the waste heat from the battery 51 is transferred by the water-water heat exchanger 18 to the coolant flowing through the heat exchange circuit 40, and the heater core 13 uses the waste heat from the battery 51 transferred to the coolant to heat the low-temperature air blown into the passenger compartment, thereby heating the passenger compartment and reducing the amount of heat heated by the water heater 15. Furthermore, by transferring the waste heat from the battery 51 to the coolant using the water-water heat exchanger 18, the temperature of the battery coolant flowing through the battery coolant flow path 18b of the water-water heat exchanger 18 is lowered. This cools the battery 51.

Next, referring to Figure 3, we will explain the flow path configuration immediately after switching from EV mode driving, as previously described with reference to Figure 2, to HV mode driving. In this case, the engine 11 is heating the vehicle cabin at a low temperature and warming up the engine 11 using exhaust heat from the battery 51. When the engine 11 switches to HV mode and starts, the engine-driven pump 12 starts in conjunction with the engine 11. The control unit 70 closes the fourth port 24 of the four-way flow control valve 20 and opens the first port 21, second port 22, and third port 23. Because the temperature of the engine 11 is low immediately after startup, the thermostat 17 closes the radiator inlet pipe 36 and sets the flow path so that coolant flows through the radiator bypass pipe 38. The electric pump 14 remains operating. Furthermore, because heating is being performed, the water heater 15 is in operation.

As indicated by the thick arrows in Figure 3, coolant pressurized by the electric pump 14 flows through the coolant flow path 15a of the water heater 15, becoming high-temperature coolant. The high-temperature coolant then flows through the radiator bypass pipe 38 into the engine-driven pump 12, where it is pressurized. The coolant pressurized by the engine-driven pump 12 passes through the coolant flow path 11a of the engine 11, where its temperature drops. The cooled coolant then flows into the four-way flow control valve 20. A portion of the coolant passes through the second port 22 and the coolant flow path 13a of the heater core 13 to exchange heat with the low-temperature air blown into the vehicle cabin, becoming even lower-temperature coolant and returning to the electric pump 14.

In addition, another portion of the cooled cooling water that flows from the cooling water flow path 11a of the engine 11 into the first port 21 of the four-way flow control valve 20 flows from the third port 23 of the four-way flow control valve 20 through the heat exchanger inlet pipe 41 and into the cooling water flow path 18a of the water-to-water heat exchanger 18, as shown by the thick dashed arrow in Figure 3.

When the hybrid vehicle 200 is running in HV mode, the battery 51 is heated by discharging to or charging from the motor 19. As described with reference to FIG. 2, the battery 51 is cooled by low-temperature refrigerant from the air conditioner flowing through the refrigerant flow path 53b of the chiller 53. The battery coolant, which has been heated after cooling the battery 51, flows through the battery coolant flow path 18b of the water-water heat exchanger 18 and exchanges heat with the other portion of the coolant, which has a lower temperature, flowing through the coolant flow path 18a of the water-water heat exchanger 18, thereby warming the other portion of the coolant. The other portion of the coolant, which has been heated and flows out of the coolant flow path 18a of the water-water heat exchanger 18, returns to the electric pump 14 along with the other portion of the coolant that has flowed through the coolant flow path 13a of the heater core 13. The heated coolant is pressurized by the engine drive pump 12 and flows into the coolant flow path 11a of the engine 11, as indicated by the thick arrow in FIG. 3, to warm up the engine 11. On the other hand, the temperature of the battery coolant at the outlet of the battery coolant flow path 18b of the water-water heat exchanger 18 is lower than the temperature of the battery coolant at the inlet of the battery coolant flow path 18b.

In this way, the waste heat from the battery 51 is transferred by the water-water heat exchanger 18 to the coolant flowing through the heat exchange circuit 40. The engine 11 is warmed up by the waste heat from the battery 51 transferred to the coolant, and the heater core 13 heats the low-temperature air blown into the passenger compartment, heating the passenger compartment. Furthermore, by transferring the waste heat from the battery 51 to the coolant in the water-water heat exchanger 18, the temperature of the battery coolant flowing through the battery coolant flow path 18b of the water-water heat exchanger 18 is lowered. This cools the battery 51.

Next, referring to Figure 4, the flow path configuration when switching from EV mode to HV mode and when the vehicle cabin is not being heated will be described. Immediately after switching from EV mode to HV mode, the engine 11 is in a low temperature state, as previously explained with reference to Figure 3. When the driving mode is switched to HV mode, the control unit 70 closes the fourth port 24 of the four-way flow control valve 20 to prevent coolant from flowing into the engine bypass circuit 45.

When the vehicle cabin is not being heated, the control unit 70 closes the second port 22 of the four-way flow control valve 20 to prevent coolant from flowing to the heater core 13. The control unit 70 also stops the electric pump 14 and the water heater 15. When the engine 11 starts, the engine-driven pump 12 starts. As shown by the thick arrow and thick dash-dot arrow in Figure 4, coolant discharged from the engine-driven pump 12 flows from the coolant flow path 11a of the engine 11 into the first port 21 of the four-way flow control valve 20, and then flows from the third port 23 through the heat exchanger inlet pipe 41 into the coolant flow path 18a of the water-to-water heat exchanger 18. The cooling water then passes through the stopped electric pump 14 and the water heater 15, and flows back to the engine-driven pump 12 via the water heater outlet pipe 35, the thermostat 17, the radiator bypass pipe 38, and the engine-driven pump inlet pipe 39.

The flow of cooling water and heat exchange in the water-water heat exchanger 18 is the same as that described above with reference to Figure 3.

In this way, the waste heat from the battery 51 is transferred by the water-water heat exchanger 18 to the coolant flowing through the heat exchange circuit 40, and the engine 11 is warmed up by the waste heat from the battery 51 transferred to the coolant. Furthermore, by transferring the waste heat from the battery 51 to the coolant using the water-water heat exchanger 18, the temperature of the battery coolant flowing through the battery coolant flow path 18b of the water-water heat exchanger 18 is lowered. This cools the battery 51.

Next, the operation of the control unit 70 will be described with reference to Figures 5 and 6. As shown in step S101 of Figure 5, the control unit 70 determines whether the start switch (not shown) of the hybrid vehicle 200 is on. If the control unit 70 determines YES in step S101 of Figure 5, the process proceeds to step S102 of Figure 5. In step S102, the control unit 70 determines whether the hybrid vehicle 200 is in EV mode based on the driving state information input from the vehicle control unit 80. If the control unit 70 determines YES in step S102 of Figure 5, the process proceeds to step S103 of Figure 5, where the control unit 70 closes the first port 21 and the third port 23 of the four-way flow control valve 20 and opens the second port 22 and the fourth port 24. The control unit 70 then operates the electric pump 14 in step S104 of Figure 5 and proceeds to step S105 of Figure 5.

In step S105 of FIG. 5, the control unit 70 obtains the temperature of the battery 51 using the battery temperature sensor 64 and determines whether the temperature of the battery 51 is equal to or higher than a predetermined value. Here, the predetermined value can be freely selected, but may be set to, for example, about 40°C, at which point cooling of the battery 51 is necessary. If the control unit 70 determines YES in step S105 of FIG. 5, it determines that cooling of the battery 51 is necessary and proceeds to step S106 of FIG. 5.

On the other hand, if the determination in step S105 of FIG. 5 is NO, the control unit 70 returns to step S101 of FIG. 5 and continues processing.

In step S106, the control unit 70 determines whether the hybrid vehicle 200 is heating the passenger compartment or whether a heating request is present, based on the air conditioning status information input from the vehicle control unit 80. If the control unit 70 determines YES in step S106 of FIG. 5, the process proceeds to step S107 of FIG. 5. In step S107 of FIG. 5, the control unit 70 compares the coolant temperature at the outlet of the heater core 13 detected by the heater core coolant temperature sensor 67 with the temperature of the battery 51 detected by the battery temperature sensor 64. If the coolant temperature at the heater core 13 is lower than the temperature of the battery 51, the control unit 70 determines YES in step S107 of FIG. 5 and proceeds to step S108 of FIG. 5. In step S108 of FIG. 5, the control unit 70 opens the third port 23 of the four-way flow control valve 20. This allows the coolant to flow through the water-water heat exchanger 18 and the heater core 13, as described with reference to FIG. 2. Then, as shown in steps S109 and S110 of FIG. 5, the control unit 70 heats the vehicle cabin by increasing the temperature of the coolant in the heater core 13 using the water-water heat exchanger 18, and heating the low-temperature air sent to the vehicle cabin using the heater core 13. Also, the water-water heat exchanger 18 lowers the temperature of the battery coolant to cool the battery 51.

On the other hand, if the control unit 70 determines NO in step S106 of FIG. 5 or NO in step S107 of FIG. 5, the control unit 70 proceeds to step S111 of FIG. 5. At this time, the control unit 70 does not open the third port 23 of the four-way flow control valve 20. Then, in step S111 of FIG. 5, the control unit 70 lowers the temperature of the battery coolant using the chiller 53, and cools the battery 51 in step S112 of FIG. 5.

On the other hand, if the control unit 70 determines NO in step S102 of FIG. 5, it proceeds to step S201 of FIG. 6. Then, in step S201 of FIG. 6, the control unit 70 determines whether or not the vehicle has transitioned to HV mode based on the driving state information input from the vehicle control unit 80. If the control unit 70 determines YES in step S201 of FIG. 6, it proceeds to step S202 of FIG. 6, where it closes the third port 23 and the fourth port 24 of the four-way flow control valve 20 and opens the first port 21 and the second port 22.

Next, in step S203 of FIG. 6, the control unit 70 obtains the temperature of the battery 51 using the battery temperature sensor 64 and determines whether the temperature of the battery 51 is equal to or higher than a predetermined value. If the control unit 70 determines YES in step S203 of FIG. 6, it determines that cooling of the battery 51 is necessary and proceeds to step S204 of FIG. 6. In step S204 of FIG. 6, the control unit 70 compares the temperature of the coolant at the outlet of the engine 11 detected by the engine coolant temperature sensor 61 with the temperature of the battery 51 detected by the battery temperature sensor 64. Then, if the temperature of the engine 11 coolant is lower than the temperature of the battery 51, the control unit 70 determines YES in step S204 of FIG. 6 and proceeds to step S205 of FIG. 6.

In step S205 of FIG. 6, the control unit 70 determines whether the hybrid vehicle 200 is heating the passenger compartment or whether a heating request is present, based on the air conditioning status information input from the vehicle control unit 80. If the control unit 70 determines YES in step S205 of FIG. 6, it proceeds to step S206 of FIG. 6 and opens the second port 22 and the third port 23 of the four-way flow control valve 20. At this time, the first port 21 of the four-way flow control valve 20 is open, and the fourth port 24 is closed. The control unit 70 then proceeds to step S207 of FIG. 6 and keeps the electric pump 14 operating. This results in a flow path configuration in which the coolant flows through the water-water heat exchanger 18 and the heater core 13, as previously described with reference to FIG. 3. Then, in step S208 of FIG. 6, the control unit 70 increases the temperature of the engine 11 coolant and the heater core 13 coolant in the water-water heat exchanger 18, and also decreases the temperature of the battery coolant in the water-water heat exchanger 18. Then, in step S209 of FIG. 6, the control unit 70 warms up the engine 11, heats the passenger compartment, and cools the battery 51.

On the other hand, if the control unit 70 determines NO in step S203 of FIG. 6, it returns to step S101 of FIG. 5. Also, if the control unit 70 determines NO in step S204 of FIG. 6, it determines that the exhaust heat of the battery 51 cannot be transferred to the coolant, and proceeds to step S111 of FIG. 5, where it cools the battery 51 using the chiller 53 as shown in steps S111 to S112 of FIG. 5.

Furthermore, if the control unit 70 determines NO in step S205 of FIG. 6, the control unit 70 proceeds to step S210 of FIG. 6, where it closes the second port 22 of the four-way flow control valve 20 and opens the third port 23, so that coolant does not flow through the heater core 13 but flows through the water-water heat exchanger 18, as described with reference to FIG. 4. Then, in step S211 of FIG. 6, the control unit 70 increases the temperature of the engine 11 coolant in the water-water heat exchanger 18 and decreases the temperature of the battery coolant in the water-water heat exchanger 18. Then, in step S212 of FIG. 6, the control unit 70 warms up the engine 11 and cools the battery 51.

After executing steps S110 and S112 in FIG. 5 or steps S209 and S212 in FIG. 6, the control unit 70 returns to step S101 in FIG. 5 and repeatedly executes steps S101 to S112 in FIG. 5 and steps S201 to S212 in FIG. 6. If the control unit 70 determines NO in step S101 in FIG. 5, it terminates the process.

As explained above, the battery temperature regulation system 100 uses the exhaust heat of the battery 51 to raise the temperature of the engine 11 coolant, thereby shortening the warm-up time of the engine 11 when switching from EV mode to HV mode. Furthermore, because the exhaust heat of the battery 51 is used to warm up the passenger compartment, the exhaust heat of the battery 51 can be effectively utilized to improve fuel efficiency.

In addition, the battery temperature regulation system 100 uses a four-way flow control valve 20 to adjust the flow rate of coolant between the heater core 13, the water-water heat exchanger 18, and the engine 11. This allows for a simple configuration that uses the exhaust heat from the battery 51 to raise the temperature of the engine 11 coolant, thereby shortening the warm-up time of the engine 11.

In the above explanation, in step S107 of FIG. 5 and step S204 of FIG. 6, the battery 51 temperature detected by the battery temperature sensor 64 is compared with the heater core 13 coolant temperature detected by the heater core coolant temperature sensor 67, or the engine outlet coolant temperature detected by the engine coolant temperature sensor 61 to make a determination, but this is not limited to this. For example, instead of the battery 51 temperature detected by the battery temperature sensor 64, the battery coolant temperature detected by the battery coolant temperature sensor 63 may be compared with the heater core 13 coolant temperature or the engine outlet coolant temperature to make a determination.

11 Engine, 11a, 13a, 15a, 16a, 18a Coolant flow path, 12 Engine-driven pump, 13 Heater core, 14 Electric pump, 15 Water heater, 16 Radiator, 17 Thermostat, 18 Water-water heat exchanger, 18b, 51a, 53a Battery coolant flow path, 19 Motor, 20 Four-way flow control valve, 21 First port, 22 Second port, 23 Third port, 24 Fourth port, 25 Air conditioning panel, 30 Engine coolant circuit, 31 Engine outlet pipe, 32 Heater core inlet pipe, 33 Heater core outlet pipe, 34 Electric pump outlet pipe, 35 Water heater outlet pipe, 36 Radiator inlet pipe, 37 Radiator outlet pipe, 38 Radiator bypass pipe, 39 Engine-driven pump inlet pipe, 40 Heat exchange circuit, 41 Heat exchanger inlet pipe, 42, 57 Heat exchanger outlet pipe, 45 engine bypass circuit, 50 battery temperature adjustment circuit, 51 battery, 52 battery coolant pump, 53 chiller, 53b refrigerant flow path, 54 chiller inlet pipe, 55 chiller outlet pipe, 56 battery outlet pipe, 58, 59 high-pressure cable, 61 engine coolant temperature sensor, 62 water heater coolant temperature sensor, 63 battery coolant temperature sensor, 64 battery temperature sensor, 65 current sensor, 66 voltage sensor, 67 heater core coolant temperature sensor, 70 control unit, 71, 81 CPU, 72, 82 memory, 80 vehicle control unit, 100 battery temperature adjustment system, 200 hybrid vehicle.

Claims (4)

A battery temperature regulation system mounted on a hybrid vehicle capable of running in an HV mode in which the vehicle runs using an engine and a vehicle drive motor, and an EV mode in which the engine is stopped and the vehicle runs using the motor,
an engine coolant circuit for circulating coolant through the engine , the engine coolant circuit including a heater core for exchanging heat with the coolant to heat air to be blown into the vehicle compartment, and a water heater provided downstream of the heater core for heating the coolant ;
a battery temperature regulation circuit that circulates a liquid heat medium through a battery that supplies power to the motor to cool or heat the battery;
a heat exchange circuit including a water-water heat exchanger connected to the engine coolant circuit so as to bypass the heater core and disposed across the battery temperature adjustment circuit to exchange heat between the coolant and the heat medium;
an engine bypass circuit connecting a downstream side of the water heater and an upstream side of the heater core so as to bypass the engine;
a four-way flow control valve provided in the engine coolant circuit between the engine and the heater core, the four-way flow control valve connecting the heat exchange circuit and the engine bypass circuit, and adjusting the flow rate of the coolant between the heater core, the water-water heat exchanger, and the engine;
an electric pump provided between the heater core and the water heater in the engine coolant circuit;
a control unit that adjusts the operation of the four-way flow control valve and the electric pump ,
the four-way flow control valve includes a first port connected to a coolant outlet of the engine, a second port connected to a coolant inlet of the heater core, a third port connected to a coolant inlet of the water-to-water heat exchanger, and a fourth port connected to a coolant outlet of the water heater;
When the hybrid vehicle shifts from the EV mode to the HV mode, and the temperature of the battery is equal to or higher than a predetermined value and the temperature of the engine coolant is lower than the temperature of the battery, the control unit opens the first port and the third port of the four-way flow control valve, closes the fourth port, and opens or closes the second port so that the engine coolant circuit and the heat exchange circuit communicate with each other, thereby causing the coolant to flow through the water-water heat exchanger, thereby increasing the temperature of the engine coolant and decreasing the temperature of the heat medium , and
When the hybrid vehicle is in the EV mode and there is a request to heat the passenger compartment, and when the temperature of the battery is equal to or higher than a predetermined value and the temperature of the coolant in the heater core is lower than the temperature of the battery, the engine coolant circuit, the engine bypass circuit, and the heat exchange circuit are communicated with each other, and the first port of the four-way flow control valve is closed and the second port, the third port, and the fourth port are opened so that the coolant does not flow to the engine, the electric pump is operated, and the coolant is caused to flow through the water-water heat exchanger and the heater core, thereby increasing the temperature of the coolant in the heater core and decreasing the temperature of the heat medium.
A battery temperature regulation system. 2. The battery temperature regulation system according to claim 1,
When the hybrid vehicle shifts from the EV mode to the HV mode, the temperature of the battery is equal to or higher than a predetermined value, and the temperature of the engine coolant is lower than the temperature of the battery,
opening the second port when there is a demand for heating the passenger compartment;
closing the second port when there is no demand for heating the passenger compartment;
A battery temperature regulation system. A hybrid vehicle capable of running in an HV mode in which the vehicle runs using an engine and a vehicle drive motor, and an EV mode in which the engine is stopped and the vehicle runs using the motor,
an engine coolant circuit for circulating coolant through the engine , the engine coolant circuit including a heater core for exchanging heat with the coolant to heat air to be blown into the vehicle compartment, and a water heater provided downstream of the heater core for heating the coolant ;
a battery temperature regulation circuit that circulates a liquid heat medium through a battery that supplies power to the motor to cool or heat the battery;
a heat exchange circuit including a water-water heat exchanger connected to the engine coolant circuit so as to bypass the heater core and disposed across the battery temperature adjustment circuit to exchange heat between the coolant and the heat medium;
an engine bypass circuit connecting a downstream side of the water heater and an upstream side of the heater core so as to bypass the engine;
a four-way flow control valve provided in the engine coolant circuit between the engine and the heater core, the four-way flow control valve connecting the heat exchange circuit and the engine bypass circuit, and adjusting the flow rate of the coolant between the heater core, the water-water heat exchanger, and the engine;
an electric pump provided between the heater core and the water heater in the engine coolant circuit;
a control unit that adjusts the operation of the four-way flow control valve and the electric pump ,
the four-way flow control valve includes a first port connected to a coolant outlet of the engine, a second port connected to a coolant inlet of the heater core, a third port connected to a coolant inlet of the water-to-water heat exchanger, and a fourth port connected to a coolant outlet of the water heater;
When the traveling mode is shifted from the EV mode to the HV mode, if the temperature of the battery is equal to or higher than a predetermined value and the temperature of the engine coolant is lower than the temperature of the battery, the control unit opens the first port and the third port of the four-way flow control valve, closes the fourth port, and opens or closes the second port so that the engine coolant circuit and the heat exchange circuit are in communication with each other, thereby causing the coolant to flow through the water-water heat exchanger, thereby increasing the temperature of the engine coolant and decreasing the temperature of the heat medium , and
When the driving mode is the EV mode and there is a request to heat the passenger compartment, when the temperature of the battery is equal to or higher than a predetermined value and the temperature of the coolant in the heater core is lower than the temperature of the battery, the engine coolant circuit, the engine bypass circuit and the heat exchange circuit are communicated with each other, and the first port of the four-way flow control valve is closed and the second port, the third port and the fourth port are opened so that the coolant does not flow to the engine, the electric pump is operated, and the coolant is caused to flow through the water-water heat exchanger and the heater core, thereby increasing the temperature of the coolant in the heater core and decreasing the temperature of the heat medium.
A hybrid vehicle characterized by : 4. The hybrid vehicle according to claim 3,
When the traveling mode transitions from the EV mode to the HV mode, if the temperature of the battery is equal to or higher than a predetermined value and the temperature of the engine coolant is lower than the temperature of the battery,
opening the second port when there is a demand for heating the passenger compartment;
closing the second port when there is no demand for heating the passenger compartment;
A hybrid vehicle characterized by: