JP2011098628A - Cooling system of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling system of a hybrid vehicle capable of more effectively using waste heat of a traveling motor and an inverter. <P>SOLUTION: This cooling system of a hybrid vehicle comprises: an engine cooling circuit 5 passing through a radiator 11 for an engine to cool cooling water by heat radiation and an engine 4; and circulating the engine cooling water; and an HV cooling circuit 3 passing through a traveling motor 2 and an inverter 1 converting direct current into alternating current and supplying it to the traveling motor 2, and circulating HV cooling water. A first water passage switch valve 17 and a second water passage switch valve 21 are provided to switch an EV cooling mode, in which the HV cooling water passing through the traveling motor 2 and the inverter 1 is introduced into the engine cooling circuit 5 and a normal mode, in which the cooling water is not communicated between the engine cooling circuit 5 and the HV cooling circuit 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine cooling circuit that circulates engine cooling water through an engine and an engine radiator that cools cooling water through heat dissipation, and an inverter that supplies a traveling motor and a direct current to an alternating current to the traveling motor. And an HV cooling circuit for circulating HV cooling water through the hybrid vehicle.

  In recent years, hybrid vehicles developed for the purpose of improving environmental performance have been popularized. The hybrid vehicle is provided with two drive sources, that is, an engine and a traveling motor, and an inverter that converts a direct current of a secondary battery mounted on the vehicle into alternating current and supplies the alternating current to the traveling motor.

  In such a hybrid vehicle, in addition to cooling the engine, it is also necessary to cool the driving motor and inverter of the HV system. Therefore, the hybrid vehicle is provided with two cooling circuits, that is, a cooling circuit for engine cooling (engine cooling circuit) and a cooling circuit for HV system (HV cooling circuit), and the cooling water is circulated through each cooling circuit. The engine and the HV system are cooled.

  By the way, the engine cooling circuit and the HV cooling circuit differ in the appropriate temperature of the cooling water. Also, the maximum allowable cooling water temperature varies between cooling circuits. For example, the cooling water in the engine cooling circuit (engine cooling water) may exceed 100 ° C. depending on the operating condition of the engine, but the cooling water in the HV cooling circuit (HV cooling water) is significantly lower in temperature ( For example, it is necessary to keep the temperature at 65 ° C. or lower. Therefore, in hybrid vehicles, it is common to provide an engine cooling circuit and an HV cooling circuit as independent cooling circuits.

  By the way, in recent years, development for the popularization of electric vehicles that run only by electricity has been promoted. Conventionally, in such an electric vehicle, a technique for utilizing waste heat of a traveling motor or an inverter for heating a vehicle interior, as disclosed in Patent Document 1, has been proposed. Therefore, by applying such technology and using waste heat from the motor and inverter for the hybrid vehicle for heating the passenger compartment, it becomes possible to more effectively manage the heat of the entire vehicle. .

JP-A-8-197937

  By the way, in recent years, the use of the engine as a heat source tends to decrease due to the miniaturization of the engine and the improvement of the thermal efficiency of the engine itself. In hybrid vehicles, the engine may be stopped during EV travel using only a motor or when the vehicle is stopped, and there is a period during which the vehicle can hardly be used as a heat source for the engine. Therefore, in a hybrid vehicle, heat supply to a heat utilization device such as heating is more severe, and heat management of the entire vehicle is regarded as more important. In that respect, the use of the waste heat of the traveling motor and the inverter in the above prior art for heating is one of the means for effectively performing the heat management of the entire vehicle. However, at present, further improvement in heat utilization efficiency is demanded, and it cannot be said that sufficient heat management is achieved.

  In general, in a hybrid vehicle, in order to reduce the manufacturing cost, the HV cooling circuit is provided only with a radiator having a lower heat dissipation capability than that provided in the engine cooling circuit. Normally, the amount of heat generated by the hybrid system is smaller than that of the engine, and it is possible to perform sufficient cooling even with a radiator having such a small heat dissipation capability. However, when the vehicle is running at a low speed and a high load, such as when climbing uphill, the hybrid system generates a large amount of heat, and a radiator with a small heat dissipation capability may not be able to perform sufficient cooling. Therefore, the output of the motor for driving must be limited to such an extent that even such a radiator does not cause overheating.

  The present invention has been made in view of such circumstances, and a problem to be solved is to provide a cooling system for a hybrid vehicle capable of performing more effective heat management.

In order to solve the above-mentioned problem, the invention described in claim 1
-Engine cooling circuit that circulates engine coolant through the engine radiator and engine that cools the coolant through heat dissipation,
An HV cooling circuit that circulates HV cooling water through a driving motor and an inverter that converts direct current to alternating current and supplies the driving motor;
It is applied to the cooling system of a hybrid vehicle provided with. The cooling system for a hybrid vehicle according to claim 1 comprises:
・ Heat transfer means to transfer heat of HV cooling water to engine cooling water,
-Utilizing the waste heat of the motor for driving and the inverter to warm up the engine by heating the engine cooling water through heat transfer from the HV cooling water to the engine cooling water by the heat transfer means,
・ Transfer heat of HV cooling water to engine cooling water through heat transfer means, and cool engine cooling water heated by the heat transfer with engine radiator, so that waste heat of running motor and inverter is used for engine To dissipate heat with a radiator,
When the heat transfer means does not transfer heat from the HV cooling water to the engine cooling water, the engine cooling circuit and the HV cooling circuit must be independent cooling circuits.
It has become.

  In such a cooling system for a hybrid vehicle according to claim 1, heat is transferred from the HV cooling water to the engine cooling water by heat transfer through the heat transfer means. Therefore, if such heat transfer is performed while the engine is warming up, the engine cooling water is heated by the heat of the HV cooling water heated by the waste heat of the driving motor and inverter. Waste heat can be used to warm up the engine. Further, the heat transferred from the HV cooling water to the engine cooling water is radiated by the engine radiator, and the waste heat of the traveling motor and the inverter is radiated by the engine radiator. Therefore, the engine radiator can be used to dissipate the waste heat of the traveling motor and the inverter.

  On the other hand, in the cooling system configured as described above, when heat transfer from the HV cooling water to the engine cooling water is not performed by the heat transfer means, the engine cooling circuit and the HV cooling circuit are independent cooling circuits. That is, the cooling circuits at this time are in a state where the circulation of the cooling water between the cooling circuits and the heat exchange between the cooling waters of both cooling circuits are not performed. Therefore, normally, the cooling water of both cooling circuits can be set to different temperatures so that each cooling circuit has an appropriate temperature, and both the cooling circuits can be efficiently cooled.

  In this way, in such a cooling system, heat transfer from the HV cooling water to the engine cooling water is performed as necessary, so that the waste heat of the driving motor and the inverter can be effectively used for warming up the engine and more effectively. Waste heat treatment can be performed. Further, normally, both cooling circuits can be made independent, and cooling can be performed in an optimum state in each cooling circuit. Therefore, according to the hybrid vehicle cooling system of the first aspect, more effective heat management can be performed.

Moreover, in order to solve the said subject, invention of Claim 2 is the following.
A first cooling circuit that circulates engine coolant through the engine radiator and engine that cools the coolant through heat dissipation;
A second cooling circuit that circulates HV cooling water through the driving motor and an inverter that converts direct current to alternating current and supplies the driving motor;
It is applied to the cooling system of a hybrid vehicle provided with. The cooling system for a hybrid vehicle according to claim 2 comprises:
Heat transfer means for transferring the heat of HV cooling water to the engine cooling water,
・ Switching means for prohibiting and allowing heat transfer from HV cooling water to engine cooling water by heat transfer heat means,
It has.

  In such a cooling system for a hybrid vehicle according to claim 2, heat transfer from the HV cooling water to the engine cooling water can be performed by heat transfer through the heat transfer means. Therefore, if such heat transfer is performed while the engine is warming up, the engine cooling water is heated by the heat of the HV cooling water heated by the waste heat of the driving motor and inverter. Waste heat can be used to warm up the engine. Further, the heat transferred from the HV cooling water to the engine cooling water is radiated by the engine radiator, and the waste heat of the traveling motor and the inverter is radiated by the engine radiator. Therefore, the engine radiator can be used to dissipate the waste heat of the traveling motor and the inverter.

  On the other hand, in the cooling system configured as described above, the heat transfer from the HV cooling water to the engine cooling water by the heat transfer heat means can be prohibited by the switching means. If heat transfer from the HV cooling water to the engine cooling water is prohibited in this way, the engine cooling circuit and the HV cooling circuit become independent cooling circuits. That is, the cooling water is not circulated between the cooling circuits and heat exchange between the cooling waters of both cooling circuits is not performed. Therefore, normally, the cooling water of both cooling circuits can be set to different temperatures and can be set to appropriate temperatures in the respective cooling circuits, and both the cooling circuits can be efficiently cooled.

  In this way, in such a cooling system, heat transfer from the HV cooling water to the engine cooling water is performed as necessary, so that the waste heat of the driving motor and the inverter can be effectively used for warming up the engine and more effectively. Waste heat treatment can be performed. Ordinarily, by making both cooling circuits independent, it is possible to perform cooling in an optimum state in each cooling circuit. Therefore, according to the hybrid vehicle cooling system of the second aspect, more effective heat management can be performed.

Incidentally, the heat management as described above can be performed more effectively by providing the hybrid vehicle cooling system according to the second aspect with the control means as described in the third aspect. That is,
・ The engine is stopped.
・ HV cooling water is hotter than engine cooling water,
If a control means for controlling the switching means to perform heat transfer from the HV cooling water to the engine cooling water is provided on the condition that at least one of
・ Efficient use of engine radiators to dissipate waste heat from motors and inverters
・ Effective use of waste heat from the motor and inverter for warming up the engine,
Is possible.

The heat transfer means provided in the hybrid vehicle cooling system as described above is
As described in claim 4, the HV cooling water after passing through the driving motor and the inverter is introduced into the engine cooling circuit so as to transfer heat from the HV cooling water to the engine cooling water.
-As in claim 5, configured as a heat exchanger that exchanges heat between HV cooling water and the engine cooling water;
Is possible.

  According to the configuration of claim 4, the cooling of the present invention can be achieved only by adding a relatively simple member such as a connecting water channel connecting both cooling circuits and a means for prohibiting and permitting the flow of the cooling water through the connecting water channel. The system can be realized. According to the fifth aspect of the present invention, the cooling system of the present invention can be realized while maintaining the independence of both cooling circuits in the sense that there is no circulation of cooling water.

Moreover, in order to solve the said subject, invention of Claim 6 is
-Engine cooling circuit that circulates engine coolant through the engine radiator and engine that cools the coolant through heat dissipation,
-An HV cooling circuit that circulates HV cooling water through a driving motor and an inverter that converts direct current to alternating current and supplies it to the driving motor;
It is applied to the cooling system of a hybrid vehicle provided with. The hybrid vehicle cooling system according to claim 6 is:
A switching means for switching between an EV cooling mode in which the HV cooling water that has passed through the driving motor and the inverter is introduced into the engine cooling circuit, and a normal mode in which no cooling water flows between the engine cooling circuit and the HV cooling circuit;
Is prepared.

  In such a cooling system, in the EV cooling mode, the HV cooling water heated by passing through the driving motor and the inverter is introduced into the engine cooling circuit so that the engine cooling water flowing through the engine cooling circuit is heated. become. Therefore, if the EV cooling mode is set while the engine is warming up, the engine cooling water is heated by the heat of the HV cooling water heated by the waste heat of the driving motor and the inverter. Waste heat can be used to warm up the engine. Further, if the EV cooling mode is set when the temperature of the HV cooling water is high, the engine radiator can be used to dissipate the waste heat of the traveling motor and the inverter.

  On the other hand, in the normal mode, both cooling circuits are independent circuits in which there is no circulation of the cooling water, so that the cooling water temperature can be made different between the cooling circuits. Therefore, in the cooling system at this time, the temperature of the cooling water is set to an appropriate temperature in each cooling circuit, and cooling can be performed in an optimal state.

  In this way, in such a cooling system, heat transfer from the HV cooling water to the engine cooling water is performed as necessary, so that the waste heat of the driving motor and the inverter can be effectively used for warming up the engine and more effectively. Waste heat treatment can be performed. Ordinarily, by making both cooling circuits independent, it is possible to perform cooling in an optimum state in each cooling circuit. Therefore, according to the hybrid vehicle cooling system of the sixth aspect, more effective heat management can be performed.

By the way, the heat management as described above can be performed more effectively by providing the hybrid vehicle cooling system according to the sixth aspect with the control means as described in the seventh aspect. That is,
・ The engine is stopped.
・ HV cooling water is hotter than engine cooling water,
If the control means for controlling the switching means to transfer heat from the HV cooling water to the engine cooling water is provided on the condition that at least one of the above conditions is established, the engine radiator can be used to dissipate the waste heat of the traveling motor and inverter. It can be used effectively, and the waste heat of the motor for driving and the inverter can be used effectively for warming up the engine.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows typically the whole structure about 1st Embodiment of the cooling system of the hybrid vehicle which concerns on this invention. The block diagram which shows the flow of the cooling water in the normal mode about the cooling system of the hybrid vehicle of the embodiment. The block diagram which shows the flow of the cooling water in the EV cooling mode about the cooling system of the hybrid vehicle of the embodiment. The flowchart which shows the process sequence of the electronic control unit in the cooling mode switching routine employ | adopted by the embodiment. The time chart which shows an example of the operation | movement aspect of the cooling system of the hybrid vehicle of the embodiment. The block diagram which shows typically the whole structure about 2nd Embodiment of the cooling system of the hybrid vehicle which concerns on this invention.

(First embodiment)
Hereinafter, a first embodiment of a cooling system for a hybrid vehicle according to the present invention will be described in detail with reference to FIGS.

  FIG. 1 shows an overall configuration of a cooling system for a hybrid vehicle according to the present embodiment. As shown in the figure, this cooling system includes two cooling systems, an HV cooling circuit 3 for cooling an HV system including an inverter 1 and a traveling motor 2, and an engine cooling circuit 5 for cooling the engine 4. It has a circuit.

  The HV cooling circuit 3 includes an HV electric water pump 6 for circulating cooling water through the HV cooling circuit 3 and an HV radiator 7 for cooling the cooling water circulating through the HV cooling circuit 3 by heat radiation. I have. In the HV cooling circuit 3, the cooling water is circulated from the HV electric water pump 6 through the HV radiator 7, the traveling motor 2 and the inverter 1 in order.

  The engine cooling circuit 5 includes an engine electric water pump 8 for circulating cooling water through the engine cooling circuit 5. The cooling water discharged from the engine electric water pump 8 is first sent to a water jacket formed inside the engine 4. The cooling water channel is branched into three water channels downstream of the engine 4, and each branched water channel is connected to the heater core 9, the throttle valve 10 and the engine radiator 11.

  Downstream of the heater core 9, a cooling water passage is branched into a water passage that passes through the exhaust heat recovery device 12 and a water passage that passes through the EGR cooler 13. The exhaust heat recovery unit 12 is a heat exchanger that recovers the heat of the exhaust and heats the cooling water, and the EGR cooler 13 cools the exhaust gas (EGR gas) that is recirculated from the exhaust system to the intake system with the cooling water. Each is configured as a heat exchanger. The cooling water that has passed through the exhaust heat recovery device 12 and the EGR cooler 13 is merged with the cooling water that has passed through the throttle valve 10, and then sent to the thermostat 14. The thermostat 14 is configured as an electric valve, and switches between allowing and shutting off the water flow of the engine radiator 11 in accordance with opening and closing thereof. The engine radiator 11 provided in the engine cooling circuit 5 is larger and has a higher cooling capacity than the HV radiator 7 provided in the HV cooling circuit 3.

  The HV cooling circuit 3 and the engine cooling circuit 5 configured as described above are connected by two water channels, that is, a first connection water channel 15 and a second connection water channel 16. The first connection water channel 15 is provided to connect the downstream side of the engine electric water pump 8 of the engine cooling circuit 5 and the downstream of the HV radiator 7 of the HV cooling circuit 3. The second connection water channel 16 is provided so as to connect the downstream side of the thermostat 14 of the engine cooling circuit 5 and the downstream side of the traveling motor 2 of the HV cooling circuit 3.

  A first water channel switching valve 17 is provided in the middle of the first connection water channel 15. The first water channel switching valve 17 switches between allowing and shutting off the passage of the cooling water in the first connection water channel 15 according to the opening and closing thereof. A second water channel switching valve 21 is provided in the middle of the second connection water channel 16. The second water channel switching valve 21 switches between allowing and shutting off the passage of the cooling water in the second connection water channel 16 according to the opening and closing thereof.

  Such a cooling system is controlled by an electronic control unit 18. The electronic control unit 18 is configured as a computer unit including a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output port (I / O). Here, the CPU performs various arithmetic processes related to the control of the cooling system, and the ROM stores a control program and data. The RAM temporarily stores the calculation results of the CPU and the detection results of the sensors, and the I / O mediates data input / output with the outside.

  The electronic control unit 18 is input with detection results of the temperature of the cooling water flowing through the engine cooling circuit 5 (engine cooling water temperature) and the temperature of the cooling water flowing through the HV cooling circuit 3 (EV cooling water temperature). And the electronic control unit 18 controls the electric water pump 6 for HV, the electric water pump 8 for engines, the thermostat 14, the 1st water path switching valve 17, and the 2nd water path switching valve 21 based on those detection results, The operation of the cooling system is managed.

  In the hybrid vehicle cooling system of the present embodiment, the electronic control unit 18 switches the cooling mode of the cooling system according to the situation. The cooling modes to be switched here are two cooling modes, a normal mode and an EV cooling mode.

  In the normal mode, the electronic control unit 18 operates the HV electric water pump 6 and the engine electric water pump 8 and controls the first water channel switching valve 17 and the second water channel switching valve 21 to be closed. As shown in FIG. 2, in the cooling system at this time, the circulation of the cooling water through the first connection water channel 15 and the second connection water channel 16 is prohibited, and the HV cooling circuit 3 and the engine cooling circuit 5 are independent of each other. Operates as a cooling circuit. That is, at this time, the cooling of the HV system and the cooling of the engine 4 are performed individually. Therefore, in the normal mode, the HV cooling water flowing through the HV cooling circuit 3 and the engine cooling water flowing through the engine cooling circuit 5 can be set to different temperatures so that each cooling circuit has an appropriate temperature. Cooling can be performed.

  On the other hand, in the EV cooling mode, the electronic control unit 18 stops the HV electric water pump 6 to operate only the engine electric water pump 8 and opens the first water channel switching valve 17 and the second water channel switching valve 21. Control as follows. As shown in FIG. 3, in the cooling system at this time, circulation of the cooling water through the first connection water channel 15 and the second connection water channel 16 is allowed, and the HV cooling circuit 3 and the engine cooling circuit 5 are integrated with each other. Operates as a cooling circuit. That is, in the cooling system at this time, a part of the cooling water (engine cooling water) discharged from the engine electric water pump 8 is introduced upstream of the inverter 1 of the HV cooling circuit 3 through the first connection water channel 15. The introduced cooling water passes through the inverter 1 and the traveling motor 2 and is returned to the upstream side of the engine electric water pump 8 of the engine cooling circuit 5.

  In such an EV cooling mode, the HV cooling water after passing through the inverter 1 and the traveling motor 2 is introduced into the engine cooling circuit 5. Accordingly, at this time, heat transfer from the HV cooling water to the engine cooling water is performed. That is, at this time, the waste heat of the inverter 1 and the traveling motor 2 is transmitted to the engine cooling water flowing through the engine cooling circuit 5.

  Therefore, in the EV cooling mode, the engine cooling water can be heated by the waste heat of the inverter 1 and the traveling motor 2, and the waste heat of the inverter 1 and the traveling motor 2 can be used for warming up the engine 4. It becomes like this.

  In the EV cooling mode, the heat transferred from the HV cooling water to the engine cooling water is radiated by the engine radiator 11, and the waste heat of the traveling motor 2 and the inverter 1 is radiated by the engine radiator 11. Will be. Therefore, in the cooling system at this time, the engine radiator 11 can be used to dissipate the waste heat of the traveling motor 2 and the inverter 1.

  In the hybrid vehicle cooling system of the present embodiment, on condition that at least one of 1) the engine 4 is stopped and 2) the HV cooling water is higher than the engine cooling water is satisfied. The cooling mode of the cooling system is set to the HV cooling mode. Such switching of the cooling mode is performed through a cooling mode switching routine shown in FIG. The processing of this routine is repeatedly executed periodically by the electronic control unit 18 after the hybrid vehicle is started.

  When this routine is started, first, in step S100, it is confirmed whether or not the hybrid vehicle is traveling in the electric vehicle mode (EV traveling). Since the engine 4 is stopped during EV traveling, it is substantially checked here whether or not the engine 4 is stopped.

  If it is during EV traveling, that is, if the engine 4 is stopped (S100: YES), the cooling mode of the cooling system is set to the EV cooling mode in step S101. On the other hand, if the EV 4 is not running and the engine 4 is operating (S100: NO), the processing of the electronic control unit 18 proceeds to step S102.

  In step S102, it is confirmed whether or not the engine (E / G) cooling water temperature is lower than the HV cooling water temperature. If the engine (E / G) cooling water temperature is lower than the HV cooling water temperature (S102: YES), the cooling mode of the cooling system is set to the EV cooling mode in step S101. On the other hand, if the engine (E / G) cooling water temperature is equal to or higher than the HV cooling water temperature (S102: NO), the cooling mode of the cooling system is set to the normal mode in step S103.

  FIG. 5 shows an example of the operation mode of the cooling system for the hybrid vehicle of this embodiment. The figure shows the operation mode of the cooling system after the hybrid vehicle is started.

  In the period up to time t1 in the figure, the hybrid vehicle is running on EV and the engine 4 is stopped. Therefore, during this period, the EV cooling mode is set as the cooling mode of the cooling system. Since the waste heat of the inverter 1 and the traveling motor 2 is transmitted to the engine cooling water at this time, it is possible to promote warm-up of the engine 4 using the waste heat.

  On the other hand, at time t1, the hybrid vehicle starts engine running. That is, the operation of the engine 4 is started from this time t1. Since the HV cooling water temperature at this time is lower than the engine cooling water temperature, the normal mode is set as the cooling mode of the cooling system.

  At time t2 thereafter, because of traveling uphill, the load on the traveling motor 2 increases, and the HV cooling water temperature exceeds the engine cooling water temperature. Therefore, at this time t2, the cooling mode of the cooling system is switched from the normal mode to the EV cooling mode again. At this time, since the engine radiator 11 having a higher heat dissipation capability than the HV radiator 7 can be used to dissipate the waste heat from the inverter 1 and the traveling motor 2, the inverter 1 and the traveling object whose waste heat amount has increased due to an increase in load. The motor 2 is cooled effectively.

  The EV cooling mode at this time is continued until time t3 when the HV cooling water temperature falls below the engine cooling water temperature. After time t3, the engine running is continued and the HV cooling water temperature is maintained below the engine cooling water temperature, so the cooling mode of the cooling system is set to the normal mode.

  In this embodiment, the second connection water channel 16 corresponds to a heat transfer means that transmits heat of the HV cooling water to the engine cooling water. Further, in the present embodiment, the first water channel switching valve 17 and the second water channel switching valve 21 correspond to a switching unit that prohibits and allows heat transfer from the HV cooling water to the engine cooling water by the heat transfer unit. ing. Further, in the present embodiment, the electronic control unit 18 uses the engine from the HV cooling water on condition that at least one of the fact that the engine is stopped and the HV cooling water is higher than the engine cooling water is satisfied. The configuration corresponds to a control unit that controls the switching unit to perform heat transfer to the cooling water.

According to the hybrid vehicle cooling system of the present embodiment described above, the following effects can be obtained.
(1) In the present embodiment, heat transfer from the HV cooling water to the engine cooling water is performed by the inflow of the HV cooling water from the HV cooling circuit 3 to the engine cooling circuit 5 through the second connection water channel 16. If such heat transfer is performed while the engine 4 is warming up, the engine cooling water is heated by the heat of the HV cooling water heated by the waste heat of the traveling motor 2 and the inverter 1. In addition, the waste heat of the inverter 1 can be used to warm up the engine 4. Further, the heat transferred from the HV cooling water to the engine cooling water is radiated by the engine radiator 11, and the waste heat of the traveling motor 2 and the inverter 1 is radiated by the engine radiator 11. Therefore, the engine radiator 11 can be used to dissipate waste heat from the traveling motor 2 and the inverter 1. On the other hand, when heat transfer from the HV cooling water to the engine cooling water is not performed, the engine cooling circuit 5 and the HV cooling circuit 3 are independent cooling circuits. That is, the cooling circuits at this time are in a state where the circulation of the cooling water between the cooling circuits and the heat exchange between the cooling waters of both cooling circuits are not performed. Therefore, normally, the cooling water of both cooling circuits can be set to different temperatures, and the appropriate temperature in each cooling circuit can be obtained. Therefore, according to the hybrid vehicle cooling system of the present embodiment, more effective heat management can be performed.

  (2) In the present embodiment, the electronic control unit 18 sets the HV cooling water on the condition that at least one of the fact that the engine is stopped and the HV cooling water is higher than the engine cooling water is satisfied. The first water channel switching valve 17 and the second water channel switching valve 21 are controlled to transfer heat from the engine to the engine coolant. According to the present embodiment, the radiator 11 for the engine is effectively used to dissipate the waste heat of the traveling motor 2 and the inverter 1, and the waste heat of the traveling motor 2 and the inverter 1 is used to warm up the engine 4. It can be used effectively.

(Second Embodiment)
Next, a second embodiment of the hybrid vehicle cooling system of the present invention will be described in detail with reference to FIG. In the present embodiment, the same components as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the first embodiment, the HV cooling water that has passed through the inverter 1 and the traveling motor 2 is introduced into the engine cooling circuit 5 as necessary, so that the waste heat of the inverter 1 and the traveling motor 2 is reduced to the engine 4 and I was trying to tell the radiator 11 for engines. In the present embodiment, heat transfer from the HV cooling circuit 3 to the engine cooling circuit 5 is performed by a heat exchanger.

  FIG. 6 shows the overall configuration of the cooling system for the hybrid vehicle of the present embodiment. As shown in the figure, the cooling system of the present embodiment also includes an HV cooling circuit 3 for cooling the HV system including the inverter 1 and the traveling motor 2, and an engine cooling circuit 5 for cooling the engine 4. These two cooling circuits are provided. However, the cooling system of the present embodiment is not provided with the first and second connection water channels 15 and 16 that directly connect the HV cooling circuit 3 and the engine cooling circuit 5, and instead, the heat exchanger 20. Is provided.

  In the engine cooling circuit 5, the heat exchanger 20 is arranged downstream of the engine electric water pump 8. Further, in the HV cooling circuit 3, two water channels, a water channel that passes through the HV radiator 7 and a water channel that bypasses the HV radiator 7, are provided in parallel downstream of the HV electric water pump 6. The heat exchanger 20 is provided in a water channel that bypasses the HV radiator 7.

  Further, a water channel switching valve 19 is provided at a branch portion of the water channel between the HV radiator 7 side and the heat exchanger 20 side of the HV cooling circuit 3. The water channel switching valve 19 is configured to selectively switch between a state in which the HV cooling water flows to the HV radiator 7 and a state to the heat exchanger 20.

  In the present embodiment, the cooling mode of the cooling system is switched by switching the water channel of the HV cooling circuit 3 by the water channel switching valve 19. The cooling modes to be switched here are two cooling modes, a normal mode and an EV cooling mode.

  In the normal mode, the water channel switching valve 19 is controlled so that the HV cooling water flows to the HV radiator 7. At this time, the HV cooling circuit 3 and the engine cooling circuit 5 operate as independent cooling circuits which are thermally separated.

  On the other hand, in the EV cooling mode, the water channel switching valve 19 is controlled so that the HV cooling water flows to the heat exchanger 20. In the heat exchanger 20 at this time, heat exchange is performed between the HV cooling water and the engine cooling water. Therefore, the waste heat of the inverter 1 and the traveling motor 2 at this time is transmitted to the engine cooling water. Therefore, when the EV cooling mode is set, the waste heat of the inverter 1 and the traveling motor 2 is used for warming up the engine 4, and the engine radiator 11 is used for heat dissipation of the waste heat of the inverter 1 and the traveling motor 2. You will be able to

  In this embodiment, the heat exchanger 20 is configured to correspond to a heat transfer means that transmits the heat of the HV cooling water to the engine cooling water. Further, in the present embodiment, the water channel switching valve 19 is configured to correspond to a switching unit that prohibits and allows heat transfer from the HV cooling water to the engine cooling water by the heat transfer unit.

  The effect (1) can also be achieved by the hybrid vehicle cooling system of the present embodiment. In addition, on the condition that at least one of the fact that the engine 4 is stopped and that the HV cooling water is higher than the engine cooling water, the water channel switching valve 19 is set to flow the HV cooling water to the heat exchanger 20. If controlled, the effect (2) can be obtained.

In addition, the said embodiment can also be changed and implemented as follows.
In the second embodiment, the water channel switching valve 19 for switching whether or not heat exchange between the HV cooling water and the engine cooling water by the heat exchanger 20 is performed is provided on the HV cooling circuit 3 side. However, a similar switching valve may be provided on the engine cooling circuit 5 side. In this case, the engine cooling circuit 5 is provided with a water channel that passes through the heat exchanger 20 and a water channel that bypasses the water channel in parallel, and a water channel switching valve that switches between which water channel the engine cooling water passes. .

  In the above embodiment, the EV cooling mode is set by setting the EV cooling mode on condition that at least one of 1) the engine is stopped and 2) the HV cooling water is hotter than the engine cooling water. Heat was transferred from the cooling water to the engine cooling water. The conditions relating to the switching of the cooling mode are not limited to this, and may be changed as appropriate. Switching from the normal mode to the EV mode is performed on the condition that the engine 4 has not been warmed up and the HV cooling water is hotter than the engine cooling water, or on the condition that the HV cooling water temperature is high. It is conceivable to switch from the normal mode to the EV mode.

  -You may change suitably the structure of the HV cooling circuit 3 in the said embodiment, and the structure of the engine cooling circuit 5. FIG. In short, the engine cooling circuit 5 is configured to circulate the engine cooling water through the engine radiator 11 and the engine 4, and the HV cooling water is circulated through the traveling motor 2 and the inverter 1. The present invention can be applied to any hybrid vehicle cooling system in which the cooling circuit 3 is configured.

  DESCRIPTION OF SYMBOLS 1 ... Inverter, 2 ... Motor for driving, 3 ... HV cooling circuit, 4 ... Engine, 5 ... Engine cooling circuit, 6 ... Electric water pump for HV, 7 ... Radiator for HV, 8 ... Electric water pump for engine, 9 ... Heater core, 10 ... throttle valve, 11 ... engine radiator, 12 ... exhaust heat recovery device, 13 ... EGR cooler, 14 ... thermostat, 15 ... first connection channel, 16 ... second connection channel (heat transfer means), 17 ... 1st waterway switching valve (switching means), 18 ... Electronic control unit (control means), 19 ... Waterway switching valve (switching means), 20 ... Heat exchanger (heat transfer means), 21 ... 2nd waterway switching valve ( Switching means).

Claims (7)

It passes through an engine radiator that cools the cooling water through heat dissipation and an engine cooling circuit that circulates the engine cooling water through the engine, and a driving motor and an inverter that converts DC current to AC and supplies the driving motor to the driving motor. A hybrid vehicle cooling system including an HV cooling circuit for circulating HV cooling water,
Heat transfer means for transferring heat of the HV cooling water to the engine cooling water;
Utilizing the waste heat of the motor for driving and the inverter to warm up the engine by heating the engine cooling water through heat transfer from the HV cooling water to the engine cooling water by the heat transfer means; ,
The HV cooling water heat is transmitted to the engine cooling water through the heat transfer means, and the engine cooling water heated by the heat transfer is cooled by the engine radiator, so that the traveling motor and the inverter Radiating the waste heat of the engine with the engine radiator;
When heat transfer from the HV cooling water to the engine cooling water by the heat transfer means is not performed, the engine cooling circuit and the HV cooling circuit are independent cooling circuits,
Hybrid vehicle cooling system comprising: It passes through an engine radiator that cools the cooling water through heat dissipation and an engine cooling circuit that circulates the engine cooling water through the engine, and a driving motor and an inverter that converts DC current to AC and supplies the driving motor to the driving motor. A hybrid vehicle cooling system including an HV cooling circuit for circulating HV cooling water,
Heat transfer means for transferring heat of the HV cooling water to the engine cooling water;
Switching means for prohibiting and allowing heat transfer from the HV cooling water to the engine cooling water by the heat transfer means;
Hybrid vehicle cooling system comprising: Heat transfer from the HV cooling water to the engine cooling water is performed on condition that at least one of the engine is stopped and the HV cooling water is hotter than the engine cooling water. The hybrid vehicle cooling system according to claim 2, further comprising control means for controlling the switching means. The heat transfer means is configured to transfer heat from the HV cooling water to the engine cooling water by introducing the HV cooling water after passing through the driving motor and the inverter into the engine cooling circuit. The cooling system for a hybrid vehicle according to any one of claims 1 to 3. The cooling system for a hybrid vehicle according to any one of claims 1 to 3, wherein the heat transfer means is configured as a heat exchanger that exchanges heat between the HV cooling water and the engine cooling water. It passes through an engine radiator that cools the cooling water through heat dissipation and an engine cooling circuit that circulates the engine cooling water through the engine, and a driving motor and an inverter that converts DC current to AC and supplies the driving motor to the driving motor. A hybrid vehicle cooling system including an HV cooling circuit for circulating HV cooling water,
An EV cooling mode in which the HV cooling water that has passed through the driving motor and the inverter is introduced into the engine cooling circuit, and a normal mode in which no cooling water flows between the engine cooling circuit and the HV cooling circuit. A hybrid vehicle cooling system comprising a switching means for switching. Heat transfer from the HV cooling water to the engine cooling water is performed on condition that at least one of the engine is stopped and the HV cooling water is hotter than the engine cooling water. The hybrid vehicle cooling system according to claim 6, further comprising control means for controlling the switching means.

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