JP6640532B2 - Hybrid car - Google Patents

Description

  The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle that makes effective use of heat generated by a battery or the like.

  The driving force control of a hybrid vehicle equipped with an engine and a motor generator (rotary electric machine) is mainly controlled by driving with the driving force of the engine and assisting with the driving force of the motor generator as needed. There are various controls such as a control that runs with the driving force of the generator and assists with the driving force of the engine as needed. However, in any control, the driving force of the engine or the motor generator is controlled in response to the required output determined from the accelerator opening, the vehicle speed, the state of charge of the battery, and the like (for example, Non-Patent Document 1).

  In control that mainly runs with the driving force of the engine, the ignition timing and the fuel injection amount output may be adjusted to raise the temperature of the exhaust purification catalyst immediately after the engine is started (for example, see Patent Document 1). Immediately after the start of the engine, if there is an acceleration request, a climb, etc., the vehicle may travel by adding the driving force of the motor generator to the driving force of the engine.

  In addition, in the control in which the vehicle travels mainly with the driving force of the motor generator, the vehicle travels only with the driving force of the motor generator at the start of traveling, but when there is an acceleration request or climbing a slope, the engine is started and the driving force of the motor generator is reduced. The vehicle runs with the driving force of the engine.

  In a hybrid vehicle, especially at the start of running (immediately after starting), the oil temperature in the transaxle case is low, and low-temperature oil has high viscosity and high frictional resistance, so that the sliding loss of the gear increases. For this reason, a hydraulic fluid storage tank that stores the transmission oil while keeping the oil warm, a hydraulic fluid feed pump that supplies the oil stored in the hydraulic fluid storage tank to the transmission, and an oil stored in the hydraulic fluid storage tank for the engine. A hydraulic fluid warmer for heating by heat, the oil stored in the hydraulic fluid storage tank is supplied to the transmission by a hydraulic fluid feed pump immediately after the start of the engine, and the temperature is relatively high immediately after the start ( A configuration has been proposed in which an oil having a low viscosity can be used (for example, see Patent Document 2).

JP 2014-234806 A JP 2004-176877 A

"Driving Force Control Method in Two-Motor Hybrid System", The Society of Automotive Engineers of Japan, Academic Lecture Preprint 982, May 1998, P73-76

  In the invention described in Patent Document 2, it is possible to reduce the frictional resistance of the oil by suppressing the oil from becoming highly viscous, but it requires a configuration such as a hydraulic fluid storage tank or a hydraulic fluid heater. , Its configuration becomes complicated. In addition, since the heat of the engine is used to heat the oil, it is necessary to drive the engine, which may deteriorate fuel efficiency.

  Therefore, an object of the present invention is to provide a hybrid vehicle that reduces the drive loss of the gear mechanism of the transaxle by heating the refrigerant in the transaxle using the heat generated by the battery and the PCU.

A hybrid vehicle according to the present invention is a hybrid vehicle including a transaxle that houses a gear mechanism that transmits driving force of an engine to driving wheels and a rotating electric machine, and that cools a battery that supplies power to the rotating electric machine. a cooling unit, a PCU cooling unit for cooling the power controller b over Ruyunitto for converting power between said rotating electric machine and the battery, and T / a cooling unit for cooling the rotary electrical machine and the gear mechanism, the battery cooling A first heat exchanger for transferring heat of the refrigerant between the first refrigerant after cooling the battery of the unit and the second refrigerant of the PCU cooling unit, and a second refrigerant of the PCU cooling unit It provided with a second heat exchanger for transferring heat of the refrigerant between the third refrigerant of the T / a cooling unit, a control unit, wherein the PCU cooling unit, before In the flow path of the second refrigerant in the PCU cooling unit, a bypass flow path bypassing the first heat exchanger and a flow path of the second refrigerant are passed through the first heat exchanger or the bypass flow path. A flow path switching valve for switching to any one of the above, wherein the control device controls the flow path switching valve when the temperature of the first refrigerant is higher than the temperature of the second refrigerant. The flow of the second refrigerant is switched to the first heat exchanger, and when the temperature of the first refrigerant is equal to or less than the temperature of the second refrigerant, the flow path switching valve is controlled. The flow of the second refrigerant is switched to the bypass flow path .

In addition, when the temperature of the first refrigerant is higher than the temperature of the second refrigerant and the temperature of the second refrigerant is higher than the temperature of the third refrigerant, the first refrigerant Is transferred to the third refrigerant via the first heat exchanger and the second heat exchanger.

  Further, the heat of the first refrigerant is transferred to the third refrigerant when the detected temperature of the battery is equal to or higher than a battery cooling temperature for determining battery cooling.

  When the temperature of the third refrigerant is higher than the temperature of the second refrigerant, the heat of the third refrigerant is transferred to the second refrigerant via the second heat exchanger. It is characterized by the following.

Further, when the temperature of the second refrigerant is higher than the temperature of the third refrigerant, the heat of the second refrigerant is transferred to the third refrigerant via the second heat exchanger. It is characterized by the following.

  ADVANTAGE OF THE INVENTION According to this invention, the drive loss of the gear mechanism of a transaxle can be reduced by heating the refrigerant | coolant in a transaxle using the heat generation of a battery and PCU, and a fuel consumption improvement by reduction of a gear drive loss. Can be achieved.

FIG. 1 is a schematic configuration diagram of a hybrid vehicle. It is a schematic structure figure of each cooling unit. It is a perspective view of a 1st heat exchanger. It is an exploded perspective view of the 2nd heat exchanger. It is a flowchart which shows control of each cooling unit. It is a flowchart which shows control of each cooling unit. FIG. 4 is a characteristic diagram illustrating a relationship between charge and discharge of a battery and temperature.

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle 100 according to an embodiment of the present invention. In FIG. 1, a hybrid vehicle 100 includes an engine 1, a battery 2, a power control unit 3 (hereinafter, referred to as a PCU3), motor generators MG1 and MG2 as rotating electric machines, a transaxle 4, wheels 5, a control device 10 And

  The engine 1 is an internal combustion engine and generates driving force for the wheels 5. The engine 1 operates in response to a drive command from the control device 10 and transmits an engine rotation speed detected by a rotation sensor (not shown) to the control device 10.

  Battery 2 is configured by a rechargeable secondary battery such as a nickel-metal hydride battery or a lithium ion battery, and supplies DC power to PCU 3. The battery 2 is provided with a battery sensor (not shown). The battery sensor measures the voltage of the battery 2 and the current input to and output from the battery 2, and transmits the measurement result to the control device 10. Control device 10 calculates the SOC of battery 2 based on the measurement result of the battery sensor. PCU 3 converts the DC power supplied from battery 2 to AC power, and outputs it to motor generator MG2.

  The transaxle 4 has a transmission and an axle as an integral structure. The transaxle 4 houses a power split mechanism 6, a speed reducer 7, and motor generators MG1 and MG2. Power split device 6 can be split into a path for transmitting the driving force output from engine 1 to wheels 5 via reduction gear 7 and a path for transmitting the driving force to motor generator MG1.

  Motor generator MG1 is rotated by the driving force from engine 1 transmitted via power split device 6 to generate power. The power generated by motor generator MG1 is supplied to PCU 3 and used as charging power for battery 2 or driving power for motor generator MG2. Thus, battery 2 is configured to be rechargeable with the electric power generated by motor generator MG1.

  Motor generator MG2 is rotated by AC power supplied from PCU3. The driving force generated by motor generator MG2 is transmitted to wheels 5 via reduction gear 7. Further, at the time of regenerative braking, motor generator MG2 is rotated as wheel 5 is decelerated. The electromotive force generated by motor generator MG2 charges battery 2 via PCU3.

  The control device 10 controls the overall operation of a device / circuit group mounted on the hybrid vehicle 100 in order to cause the hybrid vehicle 100 to run in accordance with a driver's instruction. The control device 10 includes, for example, a microcomputer or the like for executing a predetermined sequence programmed in advance and a predetermined operation.

  Next, the cooling units of the battery 2, the PCU 3, and the transaxle 4 will be described. As shown in FIG. 2, the hybrid vehicle 100 includes a battery cooling unit 20 for cooling the battery 2, a PCU cooling unit 30 for cooling the PCU 3, a power split mechanism 6 housed inside the transaxle 4, a speed reducer 7, and a motor. A T / A cooling unit 40 for cooling generators MG1 and MG2 is provided. Each of the cooling units 20, 30, and 40 constitutes an independent cooling circuit.

  First, the battery cooling unit 20 will be described. The battery cooling unit 20 has a suction port 21a communicating with the inside of the vehicle and an exhaust port 21b communicating with the luggage compartment, and blows the case 2 containing the battery 2 and the air inside the vehicle as the first refrigerant to the battery 2. A fan 22, a battery temperature sensor 23 for detecting the temperature of the battery 2, and an air temperature sensor 24 for detecting an air temperature after cooling the battery 2 are provided.

  The fan 22 is arranged in the case 21 near the suction port 21a. The battery temperature sensor 23 is provided integrally with the battery 2. The air temperature sensor 24 is arranged in the case 21 behind the battery 2. By operating the fan 22, air in the vehicle is introduced into the case 21 from the suction port 21a as shown by an arrow F1 in the figure, and the battery 2 is cooled. The air after the battery is cooled is discharged from the exhaust port 21b to the luggage compartment. The air may be exhausted outside the vehicle instead of in the luggage compartment.

  Next, the PCU cooling unit 30 will be described. The PCU cooling unit 30 is a first heat exchange that transfers heat between the flow path 31 that supplies the LLC as the second refrigerant to the PCU 3 and the air after cooling the battery 2 in the battery cooling unit 20 and the LLC. , A third heat exchanger 33 for cooling the LLC, a fan 34 for blowing outside air to the third heat exchanger 33, and circulating the LLC between the PCU 3 and the third heat exchanger 33. A pump 35 and an LLC temperature sensor 36 for detecting the temperature of the LLC flowing in the flow path 31 are provided.

  A first heat exchanger 32 is provided in the flow path 31. The first heat exchanger 32 is arranged inside the case 21 between the battery 2 and the exhaust port 21b. That is, the LLC is circulated inside the first heat exchanger 32, and is disposed at a position where the air after cooling the battery 2 circulates.

  The flow path 31 is provided with a first branch flow path 31 a as a bypass flow path that bypasses the first heat exchanger 32. A first switching valve 37 is provided at the branch between the flow path 31 toward the first heat exchanger 32 and the first branch flow path 31a as a flow path switching valve for switching the flow of LLC in the flow path 31. Have been.

  As the first switching valve 37, for example, a solenoid valve is used. Normally, as shown by an arrow F2 in the figure, the LLC flowing through the flow path 31 flows so as to flow to the first heat exchanger 32. When the first switching valve 37 is turned on, the LLC flowing through the flow path 31 bypasses the first heat exchanger 32 as shown by an arrow F3 in FIG. The flow path is switched so as to flow to the branch flow path 31a.

  In addition, the flow path 31 is provided with a second branch flow path 31 b that bypasses the third heat exchanger 33. A second switching valve 38 for switching the flow of LLC in the flow path 31 is provided at a branch between the flow path 31 toward the third heat exchanger 33 and the second branch flow path 31b.

  As the second switching valve 38, for example, a solenoid valve is used. Normally, as shown by an arrow F4 in the figure, the LLC flowing through the flow path 31 flows so as to flow to the third heat exchanger 33. When the second switching valve 38 is turned on, the LLC flowing through the flow path 31 bypasses the third heat exchanger 33 and the second switching valve 38 is turned on as shown by an arrow F5 in the drawing. The flow path is switched so as to flow to the branch flow path 31b.

  As shown in FIG. 3, the first heat exchanger 32 includes an inflow port 32a into which the LLC flows, a plurality of fine channels 32b for performing heat exchange with the air after cooling the battery 2, and an LLC after the heat exchange. And an outlet 32c for discharging air. The fine flow channel 32b is configured by arranging a plurality of fine flow channels having an inner diameter of several millimeters or less, and uses a so-called microchannel.

  The LLC flowing from the inflow port 32a flows through the plurality of fine flow paths 32b, and is discharged to the flow path 31 from the discharge port 32c. While the LLC circulates through the plurality of fine channels 32b, heat exchange with the air after cooling the battery 2 is performed via the fine channels 32b. Further, by using the microchannel, the heat exchanger can be downsized.

  The third heat exchanger 33 uses the same type of heat exchanger as the first heat exchanger 32. In the third heat exchanger 33, the air is blown by the fan 34 to the fine flow path, thereby performing heat exchange between the blown air and the LLC to cool the LLC.

  Further, the flow path 31 is provided with a second heat exchanger 50 that performs heat exchange between ATF as the third refrigerant of the T / A cooling unit 40 and LLC.

  Next, the T / A cooling unit 40 will be described. The T / A cooling unit 40 includes a pump 41 for circulating the ATF between the transaxle 4 and the second heat exchanger 50, as shown by an arrow F6 in the drawing, and a flow path 41 for supplying ATF to the transaxle 4. 42, and an ATF temperature sensor 43 for detecting the temperature of the ATF flowing in the flow path 41.

  A part of the flow path 41 of the T / A cooling unit 40 is adjacent to the flow path 31 of the PCU cooling unit 30, and a second heat exchanger 50 is provided in this adjacent part. As the second heat exchanger 50, for example, a gasket-type plate heat exchanger is used.

  As shown in FIG. 4, the second heat exchanger 50 includes a plate laminate 52 in which a plurality of heat transfer plates 51 are laminated, and a pair of pressure-resistant frames 53 that press the plate laminate 52 from both ends. I have. A gasket 54 is inserted between adjacent heat transfer plates 51, and a gasket 55 is inserted between each heat transfer plate 51 at both ends of the plate laminate 52 and a pair of pressure-resistant frames 53.

  Each of the plurality of heat transfer plates 51 is formed by press-forming a vertically long, substantially rectangular thin metal plate into a similar wavy shape, and has circular flow passage holes 51a to 51d at four corners for refrigerant flow. At the periphery of each heat transfer plate 51, a concave wave-like gasket groove (not shown) into which gaskets 54 and 55 are fitted is formed, and at the center portion, a concave-convex wave-like heat transfer part (not shown) is formed. Such a corrugated portion of the heat transfer plate 51 increases the pressure resistance of the flow passage formed between the heat transfer plates 51 against the internal pressure, and stabilizes the sealing performance by positioning and holding the gaskets 54 and 55.

  The gasket 54 inserted between the two adjacent heat transfer plates 51 includes a fluid passage seal portion surrounding the pair of upper and lower flow passage holes 51a to 51d of the heat transfer plate 51 in communication with each other, and another pair of upper and lower flow passages. It has a hole sealing portion for sealing around each of the road holes 51a to 51d. By inverting the direction of each heat transfer plate 51 and stacking the heat transfer plates 51 one by one via a gasket 54, the channels A and B of the LLC and the ATF are alternately arranged between the heat transfer plates 51. It is formed. Arrows F7 and F8 in FIG. 4 indicate the directions in which LLC and ATF flow, respectively. Heat exchange is performed via each heat transfer plate 51 while the LLC and the ATF flow through the corresponding flow paths A and B.

  The fan 22, the battery temperature sensor 23, and the air temperature sensor 24 of the battery cooling unit 20 are electrically connected to a control device 60 that controls the flow of the refrigerant in each cooling unit. The control device 60 includes a fan 34, a pump 35, an LLC temperature sensor 36, a first switching valve 37, a second switching valve 38 of the PCU cooling unit 30, a pump 42 of the T / A cooling unit 40, and an ATF temperature. The sensor 43 is also electrically connected.

  Further, the control device 60 requires the battery cooling temperature Tbc for determining whether the cooling of the battery 2 is necessary, the LLC cooling temperature Twc for determining whether the cooling of the LLC is necessary, and the cooling of the ATF. An ATF cooling temperature Ttc for determining whether there is an ATF is stored.

  The control device 60 compares the temperature information from each of the temperature sensors 23, 24, 36, and 43 with each of the cooling temperatures Tbc, Twc, and Ttc, so that the fans 22, 34, the pumps 35, 42, and the first The operation of the switching valve 37 and the second switching valve 38 is controlled. The control by the control device 60 may be performed by the control device 10 of the hybrid vehicle 100.

  Hereinafter, the control contents of the control device 60 will be described. The control device 60 controls the first heat exchanger 32 and the third heat exchanger based on the air temperature after battery cooling in the battery cooling unit 20, the LLC temperature of the PCU cooling unit 30, and the ATF temperature of the T / A cooling unit 40. The flow of the refrigerant to the exchanger 33 is controlled.

  That is, when the air temperature after the battery cooling is higher than the LLC temperature and the ATF temperature, the heat of the air after the battery cooling is transferred to the ATF via the first heat exchanger 32 and the second heat exchanger 50. To increase the temperature of the ATF to warm the ATF. When the LLC temperature is higher than the air temperature and the ATF temperature after cooling the battery, the heat of the LLC is transferred to the ATF via the second heat exchanger 50 to increase the temperature of the ATF. Warm ATF. Further, when the ATF temperature is higher than the LLC temperature, the heat of the ATF is transferred to the LLC via the second heat exchanger 50 to lower the temperature of the ATF and cool the ATF.

  Hereinafter, specific control contents will be described with reference to flowcharts shown in FIGS. First, immediately after the start of the hybrid vehicle 100, the pumps 35 and 42 are operated, the fans 22 and 34 are stopped, and the first switching valve 37 and the second switching valve 38 are not operating. From this state, in step S10, the battery temperature Tb of the battery 2 is acquired from the detection result of the battery temperature sensor 23. Then, the obtained battery temperature Tb is compared with the battery cooling temperature Tbc stored in the control device 60.

  Here, the battery cooling temperature Tbc will be described. As shown in FIG. 7, the input / output characteristics and the charging / discharging efficiency of the battery 2 change when the temperature exceeds a predetermined temperature. Therefore, when the temperature exceeds the predetermined temperature, it is necessary to cool the battery 2 to lower the temperature of the battery 2. is there. For this reason, the battery cooling temperature Tbc is set as the predetermined temperature, and the battery 2 is cooled when the temperature of the battery 2 reaches the battery cooling temperature Tbc. On the other hand, since the internal resistance of the battery 2 increases in a low temperature state, it is desired to raise the temperature quickly in the low temperature state.

  Therefore, in step S10, when the battery temperature Tb is lower than the battery cooling temperature Tbc (YES), it is determined that the battery 2 does not need to be cooled, the fan 22 is not operated, and the temperature rise due to the self-heating of the battery 2 is performed. The process proceeds to step S20.

  When the battery temperature Tb is not lower than the battery cooling temperature Tbc, that is, when the battery temperature is equal to or higher than the battery cooling temperature Tbc (NO), it is determined that the battery 2 needs to be cooled, and the process proceeds to step S11. In step S11, the battery 2 is cooled. That is, the fan 22 is operated to blow the air inside the vehicle to the battery 2 to cool the battery 2, and the process proceeds to step S12.

  In step S12, the air temperature Tbo after battery cooling is obtained from the detection result of the air temperature sensor 24, and the LLC temperature Twh flowing through the flow path 31 is obtained from the detection result of the LLC temperature sensor 36. Then, the acquired air temperature Tbo and the LLC temperature Twh are compared. If the air temperature Tbo is higher than the LLC temperature Twh (YES), it is determined that the heat of the air can be used, and the process proceeds to step S13.

  In step S13, in the first heat exchanger 32, the heat of the air after battery cooling is transferred to the LLC. That is, since the first switching valve 37 is not turned on, the LLC flows through the first heat exchanger 32 as shown by the arrow F2 in FIG. The LLC flowing into the first heat exchanger 32 is heated by the heat of the air after cooling the battery, and is discharged from the first heat exchanger 32. Then, the process proceeds to step S20.

  On the other hand, when the air temperature Tbo is not higher than the LLC temperature Twh, that is, when it is equal to or lower than the LLC temperature Twh (NO), it is determined that the heat of the air cannot be used, and the process proceeds to step S14. In step S14, the first switching valve 37 is turned on, and the flow of LLC in the flow path 31 is switched to the first branch flow path 31a as shown by an arrow F3 in FIG. The circulation to the heat exchanger 32 is stopped, and the process proceeds to step S20. In particular, when the temperature difference between the air temperature Tbo and the LLC temperature Twh is large, the flow of the LLC to the first heat exchanger 32 is stopped, so that the LLC is prevented from being cooled by the battery-cooled air. it can. Therefore, in the PCU cooling unit 30, the heat generation of the PCU promotes the temperature rise of the LLC.

  Next, in step S20, the acquired LLC temperature Twh is compared with the LLC cooling temperature Twc. If the LLC temperature Twh is higher than the LLC cooling temperature Twc (YES), it is determined that the LLC needs to be cooled, and the process proceeds to step S21. In step S21, the fan 34 is operated. The LLC flowing through the flow path 31 flows through the third heat exchanger 33 as shown by an arrow F4 in FIG. 2, and is cooled by exchanging heat with the outside air by the third heat exchanger 33. Thereafter, the process proceeds to step S30.

  If the LLC temperature Twh is not higher than the LLC cooling temperature Twc, that is, if the LLC temperature Twh is equal to or lower than the LLC cooling temperature Twc (NO), it is determined that the LLC does not require cooling, and the process proceeds to step S22. In step S22, the second switching valve 38 is turned on, and the flow of LLC in the flow path 31 is switched to the second branch flow path 31b, as shown by an arrow F5 in FIG. The flow to the heat exchanger 33 is stopped, and the process proceeds to step S30. In particular, by stopping the flow of the LLC to the third heat exchanger 33, the temperature of the LLC is increased by the heat of the PCU.

  In step S30, the ATF temperature Tatf is obtained from the detection result of the ATF temperature sensor 43. Then, the obtained ATF temperature Tatf is compared with the LLC temperature Twh. If the ATF temperature Tatf is lower than the LLC temperature Twh (NO), it is determined that the ATF can be heated by the heat of the LLC, and the process proceeds to step S31.

  In step S31, the heat of the LLC is transferred to the ATF in the second heat exchanger 50. That is, the ATF that flows into the second heat exchanger 50 is heated by the heat of the LLC that also flows into the second heat exchanger 50, and is returned to the transaxle 4.

  As described above, when the battery 2 is cooled with air, the temperature of the air after cooling of the battery 2 is high, and the heat of the high-temperature air is effectively used. That is, the heat of the air after battery cooling is transferred to the ATF via the LLC, and the ATF is heated. Alternatively, in the PCU cooling unit 30, the LLC is heated, and the heat of the LLC is transferred to the ATF to heat the ATF.

  On the other hand, in step S30, when the ATF temperature Tatf is not lower than the LLC temperature Twh, that is, when the ATF temperature Tatf is equal to or higher than the LLC temperature Twh (YES), it is determined that the ATF cannot be heated by the heat of the LLC. The process proceeds to step S32. In step S32, the ATF temperature Tatf is compared with the ATF cooling temperature Ttc stored in the control device 60.

  If the ATF temperature Tatf is higher than the ATF cooling temperature Ttc (YES), it is determined that the ATF needs to be cooled, and the process proceeds to step S33. In step S33, the heat of the ATF is transferred to the LLC in the second heat exchanger 50. That is, since the temperature of the ATF is higher than the temperature of the LLC, the heat of the ATF transfers to the LLC, thereby lowering the temperature of the ATF and cooling the ATF.

  If the ATF temperature Tatf is not higher than the ATF cooling temperature Ttc, that is, if the ATF cooling temperature Ttc or less (NO), it is determined that the ATF does not require cooling, and the process proceeds to step S34. In step S34, the pump 35 is stopped to stop the ATF from flowing into the second heat exchanger 50. In this case, the flow of the ATF to the second heat exchanger 50 in the flow path 41 is stopped, but the lubrication and cooling by the ATF are continued inside the transaxle 4. If the ATF temperature Tatf and the LLC temperature Twh are the same temperature, no heat transfer is performed between the two, so that the operation may be continued without stopping the pump 35.

  Further, for each device operated in the above-described control, the fan 22 stops when the battery temperature Tb becomes lower than the battery cooling temperature Tbc. The first switching valve 37 is turned off when the air temperature Tbo becomes higher than the LLC temperature Twh, and switches the LLC flow in the flow path 31 to the first heat exchanger 32. The fan 34 stops when the LLC temperature Twh becomes lower than the LLC cooling temperature Twc. The second switching valve 38 is turned off when the LLC temperature Twh becomes higher than the LLC cooling temperature Twc, and switches the LLC flow in the flow path 31 to the third heat exchanger 33.

  With the configuration and control described above, the heat of the air after battery cooling quickly moves to the ATF even immediately after the start, so that the temperature of the ATF can be increased. At this time, since the heat of the air after the cooling of the battery is used, the heat of the battery 2 can be effectively used.

  In addition, even when the air temperature after cooling the battery is low and it is difficult to utilize this air heat, the first and second switching valves 37 and 38 control the LLC to the first and third heat exchangers 32 and 33. By stopping the circulation and raising the temperature of the LLC in the PCU cooling unit 30 and transferring the heat of the LLC to the ATF, the temperature of the ATF can be increased.

  Then, the ATF whose temperature has increased, that is, the ATF whose viscosity has decreased, is supplied to the power split device 6 and the speed reducer 7 inside the transaxle 4, so that the frictional resistance of the power split device 6 and the speed reducer 7 due to the ATF is reduced. As a result, the drive loss can be suppressed. It is also possible to improve fuel efficiency by suppressing the drive loss.

  When the temperature of the ATF becomes high and the ATF needs to be cooled, particularly when the ATF temperature is higher than the LLC temperature, the heat of the ATF is transferred to the LLC by the second heat exchanger 50. With this, the ATF can be cooled.

  Further, since the fan 22 is not operated until the battery temperature Tb of the battery 2 reaches the battery cooling temperature Tbc, the temperature rise due to the self-heating of the battery 2 can be promoted.

  In the above-described embodiment, the battery 2 is cooled using the air in the vehicle compartment. However, the battery 2 may be cooled using a liquid such as LLC. In this case, heat exchange is performed between the LLC of the battery cooling unit 20 and the LLC of the PCU cooling unit 30 using a gasket type plate heat exchanger as the first heat exchanger.

Reference Signs List 1 engine, 2 batteries, 3 PCU, 4 transaxle, 5 wheels, 6 power split mechanism, 7 reduction gear, 10, 60 control device, 20 battery cooling unit, 21 case, 21a suction port, 21b exhaust port, 22, 34 Fan, 23 battery temperature sensor, 24 air temperature sensor, 30 PCU cooling unit, 31, 41 flow path, 31a first branch flow path, 31b second branch flow path, 32 first heat exchanger, 32a inlet , 32b micro flow path, 32c outlet, 33 third heat exchanger, 35, 42 pump, 36 LLC temperature sensor, 37 first switching valve, 38 second switching valve, 40 T / A cooling unit, 43 ATF temperature sensor, 50 second heat exchanger, 51 heat transfer plate, 51a, 51b, 51c, 51d flow path hole, 52 plate laminate, 53 pressure-resistant frame, 54, 55 gas Tsu DOO, 100 a hybrid vehicle, MG1, MG2 motor generator, Tb battery temperature, Tbc battery cooling temperature, Tbo air temperature, Tatf ATF temperature, Ttc ATF cooling temperature, Twh LLC temperature, Twc LLC cooling temperature.

Claims (5)

A hybrid vehicle having a transaxle that houses a gear mechanism that transmits driving force of an engine to driving wheels and a rotating electric machine,
A battery cooling unit that cools a battery that supplies power to the rotating electric machine,
A PCU cooling unit for cooling the power controller B over Ruyunitto for converting power between said rotating electric machine and the battery,
A T / A cooling unit for cooling the rotating electric machine and the gear mechanism;
A first heat exchanger that transfers heat of the refrigerant between the first refrigerant after cooling the battery of the battery cooling unit and the second refrigerant of the PCU cooling unit;
A second heat exchanger that transfers heat of the refrigerant between a second refrigerant of the PCU cooling unit and a third refrigerant of the T / A cooling unit;
A control device;
Equipped with a,
The PCU cooling unit includes a bypass flow path that bypasses the first heat exchanger in the flow path of the second refrigerant in the PCU cooling unit, and a flow path of the second refrigerant that is subjected to the first heat exchange. And a flow path switching valve for switching to any of the bypass flow paths,
The control device includes:
When the temperature of the first refrigerant is higher than the temperature of the second refrigerant, the flow controller controls the flow path switching valve to switch the flow of the second refrigerant to the first heat exchanger,
When the temperature of the first refrigerant is equal to or lower than the temperature of the second refrigerant, the flow path switching valve is controlled to switch the flow of the second refrigerant to the bypass flow path. Hybrid car. The hybrid vehicle according to claim 1,
When the temperature of the first refrigerant is higher than the temperature of the second refrigerant and the temperature of the second refrigerant is higher than the temperature of the third refrigerant, the heat of the first refrigerant Is transferred to the third refrigerant via the first heat exchanger and the second heat exchanger. The hybrid vehicle according to claim 2,
A hybrid vehicle, wherein the transfer of heat of the first refrigerant to the third refrigerant is performed when a detected temperature of the battery is equal to or higher than a battery cooling temperature for determining battery cooling. The hybrid vehicle according to claim 1,
When the temperature of the third refrigerant is higher than the temperature of the second refrigerant, transferring the heat of the third refrigerant to the second refrigerant via the second heat exchanger. A hybrid vehicle characterized by: The hybrid vehicle according to claim 1,
When the temperature of the second refrigerant is higher than the temperature of the third refrigerant,
A hybrid vehicle, wherein the heat of the second refrigerant is transferred to the third refrigerant via the second heat exchanger.

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