JP6652041B2 - Vehicle cooling system - Google Patents

Description

  The present invention relates to a vehicle cooling device.

  As a cooling device for a hybrid vehicle equipped with an engine and an electric motor, an inverter cooling circuit for cooling an inverter electrically connected to the electric motor is known. It is known that an inverter cooling circuit circulates cooling water (hybrid cooling water) as a refrigerant.

  Further, an engine cooling circuit using coolant (engine coolant) different from hybrid coolant as a coolant is well known. Patent Literature 1 discloses a cooling device having an engine cooling circuit and a transaxle cooling circuit using oil as a refrigerant, in which heat is exchanged between engine cooling water and oil by a heat exchanger. I have.

JP 2013-199853 A

  In a hybrid vehicle, a cooling device having an inverter cooling circuit, an engine cooling circuit, and a transaxle cooling circuit may be mounted. In each of the cooling circuits described above, dedicated liquids such as hybrid cooling water, engine cooling water, and oil are circulated through independent flow paths. For this reason, the number of components constituting each cooling circuit increases, and the size of the cooling device as a whole increases.

  Further, in the transaxle cooling circuit described in Patent Literature 1, in a transaxle case to which oil is supplied, a portion that requires lubrication and warm-up by oil (a portion that requires lubrication) and cooling by oil is required. Part (cooling required part) is included. It is necessary to supply warm oil to gears and the like of the transmission, which are parts requiring lubrication, in order to reduce the stirring resistance due to the oil. On the other hand, it is necessary to supply low-temperature oil to the electric motor, which is a part requiring cooling, in order to cool the electric motor.

  However, in the configuration of Patent Literature 1, the oil of the transaxle cooling circuit is supplied in the transaxle case without distinction between the portion requiring lubrication and the portion requiring cooling. Therefore, when priority is given to cooling over lubrication, a portion to be cooled (portion requiring cooling) is also cooled at the same time as a portion to be heated (portion requiring lubrication). On the other hand, when lubrication is prioritized over cooling, a portion to be heated (a portion requiring lubrication) is heated simultaneously with a portion to be cooled (portion requiring cooling).

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a vehicle cooling device that can reduce the size of a cooling device and achieve both cooling performance and lubrication performance.

  The present invention relates to an oil circulation system having an oil storage unit, which is mounted on a vehicle that includes an electric motor, an inverter electrically connected to the electric motor, and a power transmission mechanism that transmits power output from the electric motor to wheels. In a vehicle cooling device including a circuit, the oil circulation circuit sucks oil stored in the oil storage unit and discharges the oil as a refrigerant supplied to the inverter and the electric motor. A first circuit provided between the first oil pump and the inverter or the electric motor, and an oil cooler that cools the oil supplied to the inverter and the electric motor; The stored oil is sucked and supplied to a lubrication-requiring part included in the power transmission mechanism without passing through the oil cooler. And having a second circuit comprising a second oil pump which discharges the oil to be.

  In the present invention, only oil is circulated in the oil circulation circuit including the inverter and the electric motor. Thereby, the size of the vehicle cooling device can be reduced. The first circuit serves as a cooling circuit, which cools the oil discharged from the first oil pump with an oil cooler and supplies the oil to an inverter or an electric motor. The second circuit supplies the oil discharged from the second oil pump to a portion requiring lubrication without being cooled by an oil cooler as a lubrication circuit. Thereby, both the cooling performance and the lubrication performance can be achieved.

  In the above invention, it is preferable that in the first circuit, the inverter and the electric motor are connected in series on a downstream side of the first oil pump, and the electric motor is provided on a downstream side of the inverter.

  In the present invention, the first circuit has an inverter between the oil cooler and the electric motor on the downstream side of the first oil pump. Comparing the heat resistant temperature of the motor and the inverter, the heat resistant temperature of the inverter is lower. According to the cooling device, the oil cooled by the oil cooler can be supplied to the inverter by the first circuit before the electric motor.

  In the above invention, it is preferable that in the first circuit, the inverter and the electric motor are connected in parallel on a downstream side of the first oil pump.

  In the present invention, the first circuit can supply the oil cooled by the oil cooler to the electric motor downstream of the first oil pump without passing through the inverter. As a result, the temperature of the oil supplied to the motor has not risen due to heat exchange with the inverter, and the motor can be cooled with low-temperature oil.

  In the above invention, it is preferable that the inverter is configured such that the oil discharged from the first oil pump flows inside as a refrigerant.

  According to the present invention, the inside of the inverter can be cooled by the oil discharged from the first oil pump. Thereby, the cooling performance of the inverter is improved and the heat resistance is also improved.

  In the above invention, it is preferable that the oil cooler is an air-cooled oil cooler that performs heat exchange between the oil and air.

  According to the present invention, since the oil discharged from the first oil pump is cooled by the air-cooled oil cooler, the cooling property of the oil is improved.

  In the above invention, the first oil pump is an electric oil pump driven by an electric motor, and the second oil pump is mounted on a vehicle including the electric motor and an engine as power sources, and the second oil pump is driven by the engine. It is preferably a mechanical oil pump.

  In the present invention, since the first oil pump is configured by the electric oil pump, it is possible to drive the first oil pump even when the engine is stopped. Further, the discharge amount of the first oil pump can be controlled by a control device such as an electronic control device.

  In the above invention, the second circuit is capable of exchanging heat between engine cooling water and the oil discharged from the second oil pump, and is configured to exchange engine oil with the oil discharged from the second oil pump. It is preferable to further include a three-phase heat exchanger configured so that heat can be exchanged therebetween.

  In the present invention, heat exchange can be performed between the engine cooling water and the oil discharged from the second oil pump by the three-phase heat exchanger, and the engine oil and the oil discharged from the second oil pump can be exchanged. Heat can be exchanged between them. Thus, the oil that has passed through the three-phase heat exchanger can be supplied to the lubrication-requiring portion.

  In the above invention, an open state provided in a circuit in which the engine cooling water circulates, in which the engine cooling water can flow through the heat exchanger, and a flow of the engine cooling water through the heat exchanger A first switching valve for switching between a closed state and a closed state where the engine oil is circulated, and an open state where the engine oil can flow through the heat exchanger and the heat exchanger. And a second switching valve for switching between a closed state in which the flow of the engine oil is not possible through the second switching valve.

  In the present invention, the state of heat exchange in the three-phase heat exchanger can be controlled by switching the open / close state of the first switching valve and the second switching valve.

  In the above invention, a first oil temperature sensor for detecting a temperature of the oil, a water temperature sensor for detecting a temperature of the engine cooling water, a second oil temperature sensor for detecting a temperature of the engine oil, and the first oil A temperature of the oil detected by a temperature sensor, a temperature of the engine cooling water detected by the water temperature sensor, and a temperature of the engine oil detected by the second oil temperature sensor; A control device that controls an opening and closing operation of the second switching valve, wherein the control device is configured to control the first switching valve and the second switching valve when the temperature of the oil is lower than a predetermined oil temperature. Preferably, at least the second switching valve is controlled to be in an open state, and a warm-up control for increasing the temperature of the oil by heat exchange in the heat exchanger is performed.

  According to the present invention, the oil supplied to the portion requiring lubrication is heated by receiving heat from at least one of engine cooling water and engine oil. Therefore, the temperature of the oil rises quickly, and the parts requiring lubrication can be warmed up early. As a result, drag loss and agitation loss generated in the portion requiring lubrication by the oil can be reduced, and fuel efficiency can be improved.

  In the above invention, when performing the warm-up control, the control device controls the first switching valve and the second switching valve to be in an open state when a temperature of the engine cooling water is higher than a predetermined water temperature. Is preferred.

  According to the present invention, the oil supplied to the portion requiring lubrication is heated by receiving the heat of the engine cooling water and the engine oil, so that the temperature of the oil rises quickly, and the portion requiring lubrication can be warmed up early. As a result, drag loss and agitation loss generated in the portion requiring lubrication by the oil can be reduced, and fuel efficiency can be improved. Furthermore, since the state of heat exchange in the three-phase heat exchanger is switched in consideration of the temperature of the engine cooling water, adverse effects on the engine side due to heat exchange in the heat exchanger can be suppressed.

  In the above invention, when performing the warm-up control, when the temperature of the engine cooling water is equal to or lower than a predetermined water temperature, and when the temperature of the oil is lower than the temperature of the engine oil, Preferably, the first switching valve is controlled to be in a closed state, and the second switching valve is controlled to be in an open state.

  In the present invention, the state of heat exchange in the three-phase heat exchanger is switched in consideration of the temperature of the engine cooling water, so that adverse effects on the engine side due to heat exchange in the heat exchanger can be suppressed. That is, when the temperature of the engine cooling water is lower than the predetermined water temperature and it is desired to warm the engine cooling water, the first switching valve is closed even when the warm-up control for warming the oil in the second circuit is performed. Heat can be suppressed from being taken by the oil in the second circuit.

  In the present invention, the oil circulation circuit has a first circuit (cooling circuit) including an inverter and an electric motor, and a second circuit (lubrication circuit) including a portion requiring lubrication. Since the oil circulation circuit circulates only the oil, the vehicle cooling device can be made smaller than when the conventional inverter cooling circuit for circulating the cooling water and the transaxle cooling circuit for circulating the oil have different structures. Further, the oil cooled by the oil cooler can be supplied to the inverter and the electric motor by the first circuit, and the oil not passing through the oil cooler can be supplied to the lubrication-requiring portion by the second circuit. Thereby, the cooling device can achieve both cooling performance and lubrication performance.

FIG. 1 is a skeleton diagram illustrating an example of a vehicle on which the vehicle cooling device is mounted. FIG. 2 is a schematic diagram illustrating a schematic configuration of the cooling device according to the first embodiment. FIG. 3 is a diagram for comparing and explaining the kinematic viscosity of oil used in the cooling device of the first embodiment and the kinematic viscosity of conventional oil. FIG. 4 is a diagram for explaining the relationship between the pump discharge amount and the oil temperature. FIG. 5 is a schematic diagram illustrating a schematic configuration of a cooling device according to a modification. FIG. 6 is a schematic diagram illustrating a schematic configuration of a cooling device according to the second embodiment. FIG. 7 is a diagram for explaining the relationship between the T / M unit loss and the T / M oil temperature. FIG. 8 is a diagram showing a temperature transition of the liquid in the normal traveling state. FIG. 9 is a flowchart illustrating an example of the heat exchange control according to the second embodiment. FIG. 10 is a schematic diagram illustrating a schematic configuration of a cooling device of a reference example. FIG. 11 is a diagram for explaining a cooling device of another reference example.

  Hereinafter, a vehicle cooling device according to an embodiment of the present invention will be specifically described with reference to the drawings.

[First Embodiment]
[1. vehicle]
FIG. 1 is a skeleton diagram illustrating an example of a vehicle on which the vehicle cooling device is mounted. The vehicle Ve is a hybrid vehicle including an engine 1, a first motor (MG1) 2, and a second motor (MG2) 3 as power sources. The engine 1 is a known internal combustion engine. Each of the motors 2 and 3 is a known motor generator having a motor function and a power generation function. Each of the motors 2 and 3 is electrically connected to a battery 22 via an inverter 21. Each of the motors 2 and 3 is a part of the transaxle case 40 requiring cooling. Inverter 21 is arranged outside transaxle case 40.

  The vehicle Ve includes a power split mechanism 5 in a power transmission path from the engine 1 to the wheels (drive wheels) 4. In the vehicle Ve, the power output from the engine 1 is split by the power split mechanism 5 into the first motor 2 side and the wheel 4 side. At that time, the first motor 2 generates electric power by the power output by the engine 1, and the electric power is stored in the battery 22 or supplied to the second motor 3 via the inverter 21.

  The input shaft 6, the power split device 5, and the first motor 2 are arranged on the same axis as the crankshaft of the engine 1. The crankshaft and the input shaft 6 are connected via a torque limiter (not shown). The first motor 2 is disposed adjacent to the power split device 5 and on the side opposite to the engine 1 in the axial direction. The first motor 2 includes a stator 2a around which a coil is wound, a rotor 2b, and a rotor shaft 2c.

  The power split mechanism 5 is a differential mechanism having a plurality of rotating elements, and in the example shown in FIG. 1, is constituted by a single pinion type planetary gear mechanism. The power split mechanism 5 is engaged with a sun gear 5S of an external gear, a ring gear 5R of an internal gear disposed concentrically with the sun gear 5S, and the sun gear 5S and the ring gear 5R as three rotating elements. And a carrier 5C which holds the pinion gear so as to be able to rotate and revolve around the sun gear 5S.

  The rotor shaft 2c of the first motor 2 is connected to the sun gear 5S so as to rotate integrally. The input shaft 6 is connected to the carrier 5C so as to rotate integrally. The engine 1 is connected to a carrier 5C via an input shaft 6. An output gear 7 that outputs torque from the power split device 5 toward the wheels 4 is integrated with the ring gear 5R. The output gear 7 is an external gear that rotates integrally with the ring gear 5R, and meshes with the counter driven gear 8b of the counter gear mechanism 8.

  The output gear 7 is connected to a differential gear mechanism 9 via a counter gear mechanism 8. The counter gear mechanism 8 has a counter shaft 8a arranged parallel to the input shaft 6, a counter driven gear 8b meshing with the output gear 7, and a counter drive gear 8c meshing with a ring gear 9a of the differential gear mechanism 9. . A counter driven gear 8b and a counter drive gear 8c are attached to the counter shaft 8a so as to rotate integrally. The wheels 4 are connected to the differential gear mechanism 9 via left and right drive shafts 10.

  The vehicle Ve is configured to add the torque output by the second motor 3 to the torque transmitted from the engine 1 to the wheels 4. The second motor 3 includes a stator 3a around which a coil is wound, a rotor 3b, and a rotor shaft 3c. The rotor shaft 3c is arranged parallel to the counter shaft 8a. A reduction gear 11 meshing with the counter driven gear 8b is attached to the rotor shaft 3c so as to rotate integrally.

  The vehicle Ve is provided with a mechanical oil pump (MOP) 101 driven by the engine 1. The mechanical oil pump 101 includes a pump rotor (not shown) that is arranged on the same axis as the crankshaft of the engine 1 and rotates integrally with the input shaft 6. For example, when the vehicle Ve moves forward by the power of the engine 1, the pump rotor of the mechanical oil pump 101 rotates in the forward direction by the torque of the input shaft 6, and the mechanical oil pump 101 discharges oil from the discharge port. The oil discharged from the mechanical oil pump 101 is supplied to a necessary lubrication part 30 (shown in FIG. 2 and the like) in the transaxle case 40 and functions as lubrication oil. The lubrication required portion 30 is a portion (mainly a gear) of the power transmission mechanism of the vehicle Ve that requires lubrication and warm-up with oil in the transaxle case 40. The power transmission mechanism is a mechanism for transmitting the power output from the power source (engine 1, first motor 2, second motor 3) of the vehicle Ve to the wheels 4. In the vehicle Ve shown in FIG. 1, the lubrication requiring section 30 includes the power split mechanism 5, the output gear 7, and the counter gear mechanism 8.

[2. Cooling system]
FIG. 2 is a schematic diagram illustrating a schematic configuration of the vehicle cooling device 100 according to the first embodiment. The vehicle cooling device (hereinafter simply referred to as “cooling device”) 100 is mounted on the vehicle Ve shown in FIG. 1 and is configured to cool the inverter 21 by lubricating oil (T / M lubricating oil) for the transmission. Have been. In this description, the lubricating oil of the transmission (T / M lubricating oil) is simply referred to as oil.

  As shown in FIG. 2, the cooling device 100 includes an oil circulation circuit 200 that circulates oil. The oil circulation circuit 200 includes a first circuit (hereinafter, referred to as a cooling circuit) 210 for cooling the inverter 21 and each of the motors 2 and 3, and a second circuit (hereinafter, referred to as “cooling circuit”) for lubricating and warming up the required lubrication unit 30. 220).

  More specifically, the oil circulation circuit 200 supplies oil to an oil passage (inverter oil passage) that supplies oil as a refrigerant to the inverter 21 and a cooling required portion in the transaxle case 40 included in the transaxle oil passage. It has a structure that communicates with the cooling oil passage. That is, in the oil circulation circuit 200 including the inverter oil passage and the transaxle oil passage, only the same liquid called oil circulates. Further, cooling device 100 pumps oil in oil circulation circuit 200 toward a supply destination by two oil pumps.

[2-1. Cooling circuit]
The cooling circuit 210 includes an electric oil pump 102 as a first oil pump, a radiator dedicated to hybrid (hereinafter referred to as “HV radiator”) 103, an inverter 21 to be cooled, motors 2 and 3 to be cooled, and oil storage. Unit 104. The cooling circuit 210 cools the oil discharged from the electric oil pump 102 by the HV radiator 103 and then supplies the oil to the inverter 21 and the motors 2 and 3.

  The electric oil pump 102 is driven by an electric motor (not shown). The electric motor is driven under the control of a control device (ECU) 150. The control device 150 is configured by a known electronic control device, and controls the drive of the electric oil pump 102. The electric oil pump 102 is driven by the control of the control device 150, and sucks oil stored in the oil storage unit 104 and discharges the oil from a discharge port. The electric oil pump 102 discharges oil supplied as a refrigerant to a cooling target (the inverter 21 and each of the motors 2 and 3). A first discharge oil passage 201 is connected to a discharge port of the electric oil pump 102. The oil discharged by the electric oil pump 102 into the first discharge oil passage 201 is pressure-fed through the cooling circuit 210 toward the inverter 21 and the motors 2 and 3 to which the oil is supplied by the discharge pressure of the electric oil pump 102. .

  The HV radiator 103 is a heat exchanger that exchanges heat between oil flowing in the cooling circuit 210 and air (for example, outside air of the vehicle Ve). That is, the HV radiator 103 is an air-cooled oil cooler arranged outside the transaxle case 40. The oil flowing in the HV radiator 103 radiates heat by exchanging heat with the outside air of the vehicle Ve. The HV radiator 103 is provided in the cooling circuit 210 between the electric oil pump 102 and the inverter 21 and each of the motors 2 and 3. The cooling circuit 210 air-cools (cools) oil pumped from the electric oil pump 102 to the inverter 21 and each of the motors 2 and 3 by the HV radiator 103. A first discharge oil passage 201 is connected to an inlet of the HV radiator 103, and a first supply oil passage 202 is connected to an outlet of the HV radiator 103.

  The first supply oil passage 202 is an oil passage between the HV radiator 103 and the inverter 21, and is an oil passage that supplies the oil that has been air-cooled by the HV radiator 103 to the inverter 21. A first supply oil passage 202 is connected to a case inlet of the inverter 21. The oil that has been air-cooled by the HV radiator 103 flows from the first supply oil passage 202 into the inside of the case of the inverter 21 and contacts the heat generating portion of the inverter 21 to directly exchange heat, thereby cooling the inverter 21.

  A second supply oil passage 203 is connected to a case outlet of the inverter 21. The second supply oil passage 203 is an oil passage between the inverter 21 and each of the motors 2 and 3, and is an oil passage for supplying oil cooled by the HV radiator 103 to each of the motors 2 and 3. In the cooling circuit 210, the inverter 21 and the motors 2 and 3 are connected in series on the downstream side of the electric oil pump 102, and the motors 2 and 3 are provided on the downstream side of the inverter 21. Since the motors 2 and 3 are disposed inside the transaxle case 40, the oil supplied to the motors 2 and 3 temporarily passes through the outside of the transaxle case 40 when passing through the HV radiator 103 and the inverter 21. Flowing.

  In the example shown in FIG. 2, the second supply oil passage 203 is an oil passage whose downstream side is branched. Second supply oil passage 203 includes an MG1 cooling pipe 203a and an MG2 cooling pipe 203b. MG1 cooling pipe 203a forms one branch oil passage, and supplies oil to first motor 2. MG2 cooling pipe 203b forms the other branch oil passage, and supplies oil to second motor 3. Specifically, the MG1 cooling pipe 203a is formed in a structure having a discharge hole for discharging oil toward the stator 2a in order to cool the stator 2a that generates heat during energization, of the first motor 2 in particular. . The MG2 cooling pipe 203b is formed in a structure having a discharge hole for discharging oil toward the stator 3a in order to cool the stator 3a that generates heat during energization, of the second motor 3 in particular. Each of the cooling pipes 203a and 203b is disposed inside the transaxle case 40.

  The oil flowing from the electric oil pump 102 to the motors 2 and 3 in the cooling circuit 210 cools the motors 2 and 3 and then flows into the oil reservoir 104 in the transaxle case 40. The oil storage section 104 includes an oil pool formed at the bottom of the transaxle case 40, an oil pan, and the like. For example, the oil after cooling the motors 2 and 3 is returned to the oil storage section 104 provided at the bottom of the transaxle case 40 by gravity or the like. As described above, when the oil circulates through the cooling circuit 210, the oil stored in the oil storage unit 104 is pumped through the cooling circuit 210 toward the inverter 21 and the motors 2 and 3 by the electric oil pump 102. After cooling the motors 2 and 3, the operation returns to the oil storage section 104 again.

[2-2. Lubrication circuit]
The lubrication circuit 220 has a mechanical oil pump 101 as a second oil pump, a lubrication required section 30 to be lubricated, and an oil storage section 104. The lubrication circuit 220 supplies the oil discharged from the mechanical oil pump 101 to the required lubrication unit 30 without air cooling by the HV radiator 103.

  The mechanical oil pump 101 is driven by the engine 1 (shown in FIG. 1), sucks oil stored in the oil storage unit 104, and discharges the oil from a discharge port. The mechanical oil pump 101 discharges oil that is supplied as lubricating oil to the lubrication requiring section 30 (gear). A third supply oil passage 204 is connected to a discharge port of the mechanical oil pump 101. The third supply oil passage 204 includes a second discharge oil passage connected to the discharge port of the mechanical oil pump 101, and a lubrication oil passage that supplies oil to the lubrication requiring unit 30 on the downstream side of the second discharge oil passage. including. The oil discharged from the mechanical oil pump 101 to the third supply oil passage 204 is pressure-fed within the lubrication circuit 220 toward the lubrication requiring part 30 by the discharge pressure of the mechanical oil pump 101. Further, since the mechanical oil pump 101 is provided inside the transaxle case 40, the entire path of the lubrication circuit 220 is formed inside the transaxle case 40. For example, the third supply oil passage 204 (lubricating oil passage) is an oil passage (shaft core oil passage) formed inside the input shaft 6 shown in FIG. including. The oil pumped in the lubrication circuit 220 from the mechanical oil pump 101 toward the required lubrication unit 30 flows from the third supply oil passage 204 (the discharge hole of the input shaft 6) to the power split mechanism 5 (the lubrication required unit 30). Discharge oil toward. The oil discharged from the third supply oil passage 204 lubricates a plurality of gears in the transaxle case 40.

  The oil after lubricating the required lubrication part 30 flows into the oil storage part 104 in the transaxle case 40. For example, the oil after lubricating the lubrication-requiring section 30 is returned to the oil storage section 104 by gravity, the rotational force of the gear (centrifugal force), or the like. As described above, when the oil circulates in the lubrication circuit 220, the oil stored in the oil storage unit 104 is pressure-fed in the lubrication circuit 220 by the mechanical oil pump 101, and after lubricating the lubrication required unit 30, The operation returns to the oil storage section 104 again.

  The required lubrication unit 30 includes another gear lubricated by oil after lubricating a certain gear. For example, in the vehicle Ve shown in FIG. 1, a third supply oil passage 204 (mainly a lubrication oil passage) is formed inside the input shaft 6, and the power split mechanism 5 (sun gear 5S, ring gear 5R, pinion gear) is formed from the input shaft 6 side. The oil after lubrication moves due to gravity, centrifugal force, etc., and lubricates other gears (output gear 7, counter gear mechanism 8). The differential gear mechanism 9 can be configured so that a part of the gear is immersed in the oil in the oil storage unit 104 to scrape up and lubricate. Further, depending on the structure of the transaxle case 40, the oil after lubricating the power split device 5 may be returned to the oil reservoir 104 before lubricating the differential gear mechanism 9. Therefore, the differential gear mechanism 9 does not have to be included in the lubrication requiring section 30.

[3. Comparison with Reference Example]
Here, in order to explain the superiority of the cooling device 100, the cooling device 100 is compared with a reference example. First, a cooling device of a reference example will be described with reference to FIG. Next, a comparison between the cooling device 100 and the reference example will be described.

[3-1. Reference example]
FIG. 10 is a schematic diagram illustrating a schematic configuration of a cooling device 300 of a reference example. In the cooling device 300 of the reference example, the inverter cooling circuit 310 and the transaxle oil passage 320 are formed by independent flow passages. Inverter cooling circuit 310 is formed by a water channel that circulates hybrid cooling water (LLC) as a refrigerant. The transaxle oil passage 320 is formed by an oil passage that circulates oil (T / M lubricating oil) as a refrigerant.

  Specifically, the inverter cooling circuit 310 includes an electric water pump (EWP) 311, an HV radiator 312 that performs heat exchange between hybrid cooling water (hereinafter, referred to as “HV cooling water”) and air, An inverter 313 electrically connected to the HV cooling water 3, a heat exchanger 314 for exchanging heat between the HV cooling water and the oil in the transaxle oil passage 320, and a reservoir tank 315 for storing the HV cooling water. Including. The inverter cooling circuit 310 is a circulation water channel for cooling the inverter 313 with the HV cooling water.

  In the inverter cooling circuit 310, the electric water pump 311 draws in the HV cooling water stored in the reservoir tank 315 and discharges it from the discharge port. The HV cooling water discharged from the electric water pump 311 is supplied to an inverter 313 after being cooled by an HV radiator 312. The inverter 313 is cooled by the HV cooling water that has been air-cooled by the HV radiator 312. After cooling the inverter 313, the HV cooling water flows into the heat exchanger 314 to perform heat exchange with oil, and is then sent to the reservoir tank 315 by pressure.

  The transaxle oil passage 320 includes a mechanical oil pump 321, a heat exchanger 314, a first motor 2, a second motor 3, a required lubrication unit 30, and an oil storage unit 322. The transaxle oil passage 320 is an oil passage that can supply the oil discharged from the mechanical oil pump 321 to the motors 2 and 3 after exchanging heat with the HV cooling water in the heat exchanger 314. (Cooling oil passage). Further, the transaxle oil passage 320 can supply oil discharged from the mechanical oil pump 321 to the lubrication-requiring portion 30 without exchanging heat between the heat exchanger 314 and the HV cooling water. Path (lubricating oil path). The oil stored in the oil storage unit 322 is oil that is not supplied to the HV radiator 312 and the inverter 313, unlike the oil storage unit 104 of the first embodiment described above.

[3-2. Comparison]
Advantages of the cooling device 100 of the first embodiment over the cooling device 300 of the reference example include a cooling performance first, a structure second, and a fluidity of oil third.

[3-2-1. Cooling performance]
Pay attention to the cooling performance of the inverter. A common point between the first embodiment and the reference example is that, inside the inverters 21 and 313, a current-carrying inverter element is a heat generating portion (heat source).

  In the inverter cooling circuit 310 of the reference example, since the HV cooling water as the refrigerant has conductivity, the HV cooling water cannot be brought into contact with the energized inverter element (inverter heating section) in consideration of safety. In the heat exchange between the inverter heating part and the HV cooling water, it is necessary to pass through an insulating plate (intervening member) such as a heat sink. Therefore, since the cooling state of the inverter heating unit by the HV cooling water is indirect cooling via the insulating plate, the thermal resistance between the HV cooling water and the inverter heating unit is increased by the amount of the insulating plate. For example, when a heat transfer member is provided in a heat transport path from an inverter element to an insulating plate (heat radiating plate), thermal resistance increases by the amount of the heat transport path. In addition, not only the heat transfer coefficient between the members forming the heat transport path but also the heat conductivity of the member itself may reduce the heat dissipation of the inverter element.

  In the cooling device 100 of the first embodiment, since the oil as the refrigerant has insulating properties, the oil can be brought into contact with the energized inverter element (inverter heating section) when cooling the inverter 21. In the cooling device 100, heat can be directly exchanged between the inverter heat generating portion and oil (refrigerant). That is, according to the cooling device 100, the inverter element can be directly cooled by the insulating refrigerant. Thereby, in the cooling device 100, an insulating plate such as a heat radiating plate is not required as in the reference example, and the thermal resistance between the refrigerant (oil) and the inverter heat generating portion can be reduced as compared with the reference example. Therefore, according to the first embodiment, the cooling performance of the inverter element is improved and the cooling performance of the inverter 21 is improved as compared with the reference example. In addition, the heat resistance of the inverter 21 is improved by improving the cooling performance of the inverter element. The inverter element is a package covered by a housing.

  Further, the cooling device 300 of the reference example has a configuration in which one mechanical oil pump 321 supplies oil to both the motors 2 and 3 (cooling required parts) and the lubrication required parts 30 by pressure. Therefore, it becomes difficult to control the amount of oil supplied to the portion requiring cooling and the amount of oil supplied to the portion 30 requiring lubrication. For example, in a vehicle state where warming of the lubrication-necessary part 30 is required by oil, such as at the time of a cold start of the vehicle Ve (emphasis on warm-up), the mechanical oil pump 321 is used to supply oil to the lubrication-necessary part 30. In spite of being driven, a part of the oil is supplied to the parts requiring cooling (the motors 2 and 3). In this case, there is a possibility that the oil supply amount for warming up may be reduced. In this case, the oil is supplied to the portion requiring cooling that requires less cooling. In this case, a loss (stirring loss) caused by the rotating rotors of the motors 2 and 3 stirring the oil and a loss (dragging loss) caused by being dragged by the oil may increase. Alternatively, in a vehicle state where cooling of at least one of the first motor 2 and the second motor 3 is required (cooling is emphasized), a mechanical type is used to supply oil as a refrigerant to the cooling required parts (the motors 2 and 3). Although the oil pump 321 is driven, a part of the oil is supplied to the lubrication-requiring section 30. In this case, the supply amount of the oil as the refrigerant is reduced, and the cooling performance of each of the motors 2 and 3 may be reduced. In addition, the amount of oil supplied to the necessary lubrication unit 30 becomes excessive, and the agitation loss and drag loss generated in the required lubrication unit 30 may increase. As described above, when the agitation loss and the drag loss in the motor system (the motors 2 and 3) and the lubrication system (the lubrication required portion 30) are increased due to the oil, the fuel efficiency may be deteriorated.

  Further, in the cooling device 300 of the reference example, oil in the transaxle oil passage 320 radiates heat to the HV cooling water in the inverter cooling circuit 310 via the heat exchanger 314. That is, the HV cooling water is air-cooled by the HV radiator 312, but the heat of the oil is radiated by the HV radiator 312 via the HV cooling water. Therefore, the heat radiation efficiency of the oil is not good. In this case, the effect of cooling the motors 2 and 3 by the oil is reduced.

  In the first embodiment, the oil circulation circuit 200 including the cooling circuit 210 and the lubrication circuit 220 includes elements that need to be cooled (the inverter 21 and the motors 2 and 3) and elements that need to be warmed up (the lubrication needs part 30). And oil at different temperatures can be supplied. Further, the electric oil pump 102 provided as the first oil pump provided in the cooling circuit 210 and the mechanical oil pump 101 provided as the second oil pump provided in the lubrication circuit 220 can be driven separately. For example, when the vehicle Ve is traveling at a high vehicle speed or traveling on an uphill road, and the vehicle is in a vehicle state that requires cooling of the motors 2 and 3 (cooling is important), the control device 150 controls the electric oil pump 102 to drive. be able to. Thereby, the cooling performance and the lubrication performance of the cooling device 100 can be compatible.

  In the cooling device 100 of the first embodiment, the electric oil pump 102 supplies oil to the inverter 21 in the cooling circuit 210 and each of the motors 2 and 3, and can be controlled by the control device 150. Therefore, the oil temperature management including the inverter temperature and the motor temperature can be performed by the electric oil pump 102. In contrast, in the reference example, since the electric water pump 311 for the inverter cooling circuit 310 and the mechanical oil pump 321 for the transaxle oil passage 320 are provided, the inverter temperature and the motor temperature are separately managed. I was Therefore, according to the first embodiment, it becomes easier to manage to the optimum oil temperature according to the traveling state of the vehicle Ve than in the reference example.

[3-2-2. Construction]
Further, with respect to the structure, according to the first embodiment, the number of component parts can be reduced as compared with the reference example. For example, the heat exchanger 314, the reservoir tank 315, and a part of the piping forming the water channel of the reference example can be reduced. Furthermore, according to the first embodiment, in the reference example, HV cooling water, which is a component dedicated to the inverter cooling circuit 310, is not required, so that one refrigerant can be reduced. In short, in the cooling device 100 of the first embodiment, since only one refrigerant (oil only) is used, redundant element parts are not required, and a small and lightweight system configuration can be realized. Further, the cost can be reduced by reducing the number of components (including the HV cooling water). In addition, in the case of the large-sized cooling device 300, the mountability on a vehicle is poor, and the assemblability is deteriorated.

[3-2-3. Oil fluidity]
The fluidity of the oil will be described with reference to FIGS. FIG. 3 is a diagram for comparing and explaining the kinematic viscosity of the oil used in the cooling device 100 of the first embodiment and the kinematic viscosity of the conventional oil. FIG. 4 is a diagram for explaining the relationship between the pump discharge amount and the oil temperature. In this description, the oil used in the cooling device 100 is referred to as “main oil”, and the oil used in the conventional cooling device is referred to as “conventional oil”. The solid line shown in FIG. 3 represents the kinematic viscosity of the present oil, and the broken line represents the kinematic viscosity of the conventional oil. The solid line shown in FIG. 4 represents the discharge amount (flow rate) with the present oil, and the broken line represents the discharge amount (flow rate) with the conventional oil.

  As shown in FIG. 3, the kinematic viscosity of the present oil is lower than the kinematic viscosity of the conventional oil at any oil temperature, and the viscosity decreases particularly in a low temperature range. Specifically, in the oil temperature range where the oil temperature is negative, the present oil has a significantly lower viscosity than the conventional oil. Even in the oil temperature range where the oil temperature is positive, the viscosity of the present oil greatly decreases. For example, in the oil temperature range of about 10 to 30 ° C., the kinematic viscosity of the present oil is reduced by about 60% compared to the conventional oil.

  Therefore, by using the present oil, which is a low-viscosity oil, for the cooling device 100, it is possible to reduce the pressure loss that occurs when the present oil flows in the oil circulation circuit 200. This makes it possible to flow the main oil as a refrigerant inside the inverter 21 while suppressing an increase in pressure loss. In addition, the drag resistance of the oil is reduced in the rotating members such as the rotors of the motors 2 and 3 and the lubrication-requiring portion 30 that come into contact with the oil. Thus, the oil temperature range in which the electric oil pump 102 can operate can be extended to a very low temperature range. That is, the operating limit oil temperature of the electric oil pump 102 decreases to a very low temperature. The operation limit oil temperature is an oil temperature at which the discharge amount (flow rate per unit time) of the electric oil pump 102 becomes a necessary discharge amount. FIG. 4 shows the difference between the present oil and the conventional oil with respect to the operation limit oil temperature of the electric oil pump 102.

  As shown in FIG. 4, the operation limit oil temperature Tlim of the electric oil pump 102 that discharges the present oil is extremely low at minus several tens degrees (for example, about −20 to −40 ° C.). On the other hand, the operation limit oil temperature of the electric oil pump 102 that discharges the conventional oil is near zero degrees. As described above, the oil temperature range in which the electric oil pump 102 can operate extends to the extremely low temperature range including minus several tens degrees. Therefore, the fluidity of the present oil is ensured even when the outside air temperature is extremely low at around −30 ° C. In addition, the discharge amount when the present oil is used is larger than the discharge amount when the conventional oil is used at any oil temperature, and the discharge amount is significantly increased especially in a low temperature range.

  As described above, the cooling device 100 of the first embodiment includes the oil circulation circuit 200 that circulates only oil to the inverter oil passage and the transaxle oil passage. Thereby, the size of the cooling device 100 can be reduced. In the oil circulation circuit 200, oil cooled by the HV radiator 103 by the cooling circuit 210 is supplied to the inverter 21 and each of the motors 2 and 3 (required cooling unit), and oil not cooled by the HV radiator 103 is lubricated by the lubrication circuit 220. It can be supplied to the necessary part 30. This allows the cooling device 100 to achieve both cooling performance and lubrication performance. Further, the oil can be cooled (air-cooled) by the HV radiator 103, so that the cooling property of the oil is improved. In addition, since the air-cooled oil is supplied to the motors 2 and 3, the cooling performance of the motors 2 and 3 is improved. In the cooling circuit 210, the inverter 21 and one of the motors 2 and 3 are arranged in series. Thus, it is possible to suppress a reduction in the amount of oil supplied to each of the motors 2 and 3.

  Further, by improving the oil cooling property, the loss (copper loss, iron loss) of each motor 2, 3 can be reduced, and the fuel efficiency is improved and the heat resistance of each motor 2, 3 is improved. Further, since the cooling performance of the inverter 21 is also improved, the loss (such as copper loss) of the inverter 21 can be reduced, and the fuel efficiency is improved and the heat resistance of the inverter 21 is improved.

[4. Modification]
FIG. 5 is a schematic diagram illustrating a schematic configuration of a cooling device 100 according to a modification. In the description of the modified example, the description of the same configuration as that of the above-described first embodiment will be omitted, and the reference numerals will be cited.

  As shown in FIG. 5, in the cooling device 100 of the modified example, in the cooling circuit 210 of the oil circulation circuit 200, the inverter 21 and each of the motors 2 and 3 are connected in parallel on the downstream side of the electric oil pump 102. . Specifically, in the cooling circuit 210, the inverter 21, the first motor 2, and the second motor 3 are arranged in parallel.

  More specifically, an oil passage after air cooling 205 is connected to an outlet of the HV radiator 103. In the oil passage 205 after the air cooling, the oil passage on the downstream side is branched at a branch point P. At the branch point P, the post-air-cooling oil passage 205, the first supply oil passage 202, and the second supply oil passage 203 (the MG1 cooling pipe 203a and the MG2 cooling pipe 203b) communicate with each other. That is, the oil passage inside the case of the inverter 21 communicates with the HV radiator 103 via the first supply oil passage 202 and the air passage 205 after air cooling. The MG1 cooling pipe 203a of the first motor 2 communicates with the HV radiator 103 via the oil passage 205 after air cooling. The MG2 cooling pipe 203b of the second motor 3 communicates with the HV radiator 103 via the oil passage 205 after air cooling. That is, in the cooling circuit 210 of the modified example, the oil supplied to each of the motors 2 and 3 is configured to temporarily flow outside the transaxle case 40 to pass through the HV radiator 103 without passing through the inverter 21. Have been.

  According to the cooling device 100 of this modified example, the oil cooled by the HV radiator 103 can be supplied to each of the motors 2 and 3 without passing through the inverter 21. As a result, the temperature of the oil supplied to each of the motors 2 and 3 does not increase due to the cooling of the inverter 21, and the motors 2 and 3 can be cooled with low-temperature oil. Therefore, the cooling performance of each of the motors 2 and 3 is improved.

  The inverter 21 and the motors 2 and 3 are arranged in series as in the first embodiment described above, and the inverter 21 and the motors 2 and 3 are arranged in parallel as in this modification. And the case where it was done. In the cooling circuit 210, when the inverter 21 and the motors 2 and 3 are arranged in series, the cooling circuit 210 is supplied to the motors 2 and 3 more than when the inverter 21 and the motors 2 and 3 are arranged in parallel. Oil volume is high and oil temperature is high. In the cooling circuit 210, when the inverter 21 and each of the motors 2 and 3 are arranged in parallel, the cooling circuit 210 is supplied to each of the motors 2 and 3 than when the inverter 21 and each of the motors 2 and 3 are arranged in series. Oil volume is low and oil temperature is low.

  The vehicle cooling device according to the present invention is not limited to the above-described first embodiment and the modifications, and can be appropriately changed without departing from the object of the present invention.

  For example, the structure and arrangement of the mechanical oil pump 101 are not particularly limited as long as they can be formed inside the transaxle case 40. For example, the mechanical oil pump 101 does not have to be arranged on the same axis as the crankshaft of the engine 1. In this case, the mechanical oil pump 101 and the input shaft 6 are connected so as to be able to transmit power via a mechanism such as a gear mechanism or a chain mechanism.

  The types of the two oil pumps included in the cooling device 100 are not limited to the above-described first embodiment. That is, the first oil pump included in the cooling circuit 210 is not limited to the electric oil pump 102, and the second oil pump included in the lubrication circuit 220 is not limited to the mechanical oil pump 101. For example, both the first oil pump and the second oil pump may be electric oil pumps. In this case, the second oil pump for pumping the oil in the lubrication circuit 220 is an electric oil pump, and the control device 150 can control the second oil pump in the lubrication circuit 220. Further, according to cooling device 100, it is possible to drive the second oil pump including the electric oil pump while vehicle Ve is stopped. Further, the vehicle on which the cooling device 100 is mounted is not limited to a hybrid vehicle, and includes an electric vehicle (EV vehicle) using only a motor as a power source.

  Furthermore, in the cooling device 100, the number of motors included in the cooling required part is not limited, and a number of motors other than two may be set as the cooling target. In the first embodiment described above, the case where the vehicle Ve is a two-motor type hybrid vehicle has been described, but the vehicle may be a one-motor type hybrid vehicle. Alternatively, the cooling device 100 may set three or more motors as cooling targets.

  Further, cooling device 100 may have a configuration having a water-cooled oil cooler instead of HV radiator 103 which is an air-cooled oil cooler. The cooling device 100 may include an oil cooler that can cool oil supplied to the inverter 21 to be cooled and the motors 2 and 3. Therefore, whether the oil cooler is air-cooled or water-cooled is not limited. For example, when the cooling device 100 has a water-cooled oil cooler, the water-cooled oil cooler may be a heat exchanger that exchanges heat between oil flowing through the cooling circuit 210 and engine cooling water. .

  Further, the differential gear mechanism 9 may be included in the lubrication requiring section 30. In short, whether or not the differential gear mechanism 9 is included in the lubrication requiring section 30 is not particularly limited.

[Second embodiment]
Next, a cooling device 100 according to a second embodiment will be described with reference to FIGS. The cooling device 100 according to the second embodiment is different from the first embodiment in that engine cooling water (hereinafter referred to as “ENG cooling water”), engine oil (hereinafter referred to as “ENG oil”), and T / M lubricating oil (hereinafter referred to as “ENG oil”). T / M oil) is provided with a three-phase heat exchanger for performing heat exchange. In the description of the second embodiment, the description of the same components as those of the first embodiment will be omitted, and the reference numerals will be cited.

[5. Cooling system]
FIG. 6 is a schematic diagram illustrating a schematic configuration of the cooling device 100 according to the second embodiment. As shown in FIG. 6, a cooling device 100 according to the second embodiment is a three-phase heat exchanger (hereinafter simply referred to as a “heat exchanger”) that performs heat exchange between ENG cooling water, ENG oil, and T / M oil. ) 105). The oil circulation circuit 200 prevents the T / M oil flowing through the lubrication circuit 220 from flowing into the heat exchanger 105, but the T / M oil flowing through the cooling circuit 210 from flowing into the heat exchanger 105. Is configured. Further, a lubrication circuit 220, an ENG cooling circuit 410, and an ENG oil circuit 420 are connected to the heat exchanger 105.

[5-1. Lubrication circuit]
The lubrication circuit 220 includes the mechanical oil pump 101, the heat exchanger 105, the lubrication required unit 30, and the oil storage unit 104. The lubrication circuit 220 supplies the T / M oil discharged from the mechanical oil pump 101 to the required lubrication unit 30 via the heat exchanger 105.

  A second discharge oil passage 206 is connected to a discharge port of the mechanical oil pump 101. The T / M oil discharged from the mechanical oil pump 101 into the second discharge oil passage 206 is pressure-fed through the lubrication circuit 220 toward the heat exchanger 105 by the discharge pressure of the mechanical oil pump 101, and the heat thereof It is pressure-fed to the required lubrication part 30 via the exchanger 105.

  The heat exchanger 105 is a heat exchanger configured to be able to exchange heat among three liquids of T / M oil, ENG cooling water, and ENG oil. That is, the heat exchange is possible between the T / M oil and the ENG cooling water, and the heat exchange is possible between the T / M oil and the ENG oil. Further, heat exchange is possible between ENG cooling water and ENG oil. A second discharge oil passage 206 is connected to an inlet of the heat exchanger 105 in the lubrication circuit 220. A fourth supply oil passage 207 is connected to an outlet of the heat exchanger 105 in the lubrication circuit 220. The fourth supply oil passage 207 is a lubrication oil passage that supplies oil to the required lubrication unit 30 on the downstream side of the heat exchanger 105.

  Further, the lubrication circuit 220 is provided with a first oil temperature sensor 151 for detecting the temperature Ttm of the T / M oil. For example, the first oil temperature sensor 151 is provided in the second discharge oil passage 206 in the lubrication circuit 220 and detects the temperature Ttm of the T / M oil discharged from the mechanical oil pump 101. Then, the T / M oil temperature (hereinafter referred to as “T / M oil temperature”) Ttm detected by the first oil temperature sensor 151 is input to the control device 150 as a detection signal (temperature information).

[5-2. ENG cooling circuit]
The ENG cooling circuit 410 is a circuit in which ENG cooling water circulates. As shown in FIG. 6, the ENG cooling circuit 410 includes a heat exchanger 105 and a first switching valve (ON-OFF) that selectively shuts off the flow of ENG cooling water returning to the engine 1 via the heat exchanger 105. 411). The ENG cooling circuit 410 includes a known configuration such as a water pump (not shown).

  A first water passage 412 for supplying ENG cooling water to the heat exchanger 105 is connected to a cooling water outlet of the engine 1 and a cooling water inlet of the heat exchanger 105. Further, a second water passage 413 for supplying ENG cooling water after heat exchange in the heat exchanger 105 to the engine 1 is connected to a cooling water outlet of the heat exchanger 105 and a cooling water inlet of the engine 1. In the example shown in FIG. 6, a first switching valve 411 is provided in the second water channel 413.

  The first switching valve 411 is in an open state (ON) where the ENG cooling water returning to the engine 1 via the heat exchanger 105 can flow, and the ENG cooling water returning to the engine 1 via the heat exchanger 105. Switch to the closed state (OFF) where distribution is not possible. The first switching valve 411 is configured by, for example, an electromagnetic valve or the like, and the opening and closing operation is controlled by the control device 150. When the first switching valve 411 is in the open state, the ENG cooling water flows from the engine 1 to the heat exchanger 105 in the first water passage 412 and flows from the heat exchanger 105 to the engine 1 in the second water passage 413. ENG cooling water flows. On the other hand, when the first switching valve 411 is in the closed state, the ENG cooling circuit 410 does not generate the flow of the ENG cooling water returning to the engine 1 via the heat exchanger 105.

  Further, the ENG cooling circuit 410 is provided with a water temperature sensor 152 for detecting the temperature of the ENG cooling water (hereinafter referred to as “ENG cooling water temperature”) Thw. The water temperature sensor 152 is installed in the ENG cooling circuit 410 on the upstream side of the heat exchanger 105. Further, information on the ENG cooling water temperature Thw detected by the water temperature sensor 152 is input to the control device 150 as a detection signal.

[5-3. ENG oil circuit]
The ENG oil circuit 420 is a circuit in which ENG oil circulates. As shown in FIG. 6, the ENG oil circuit 420 includes a heat exchanger 105 and a second switching valve (ON-OFF) that selectively shuts off the flow of ENG oil returning to the engine 1 via the heat exchanger 105. 421).

  A first oil passage 422 that supplies ENG oil to the heat exchanger 105 is connected to an ENG oil outlet of the engine 1 and an ENG oil inlet of the heat exchanger 105. Further, a second oil passage 423 for supplying ENG oil after heat exchange in the heat exchanger 105 to the engine 1 is connected to an ENG oil outlet of the heat exchanger 105 and an ENG oil inlet of the engine 1. In the example shown in FIG. 6, a second switching valve 421 is provided in the second oil passage 423.

  The second switching valve 421 is in an open state (ON) where the flow of the ENG oil returning to the engine 1 via the heat exchanger 105 is allowed, and the flow of the ENG oil returning to the engine 1 via the heat exchanger 105 is maintained. Switching to an impossible closed state (OFF). The second switching valve 421 is configured by, for example, an electromagnetic valve or the like, and the opening and closing operation is controlled by the control device 150. When the second switching valve 421 is in an open state, ENG oil flows from the engine 1 to the heat exchanger 105 through the first oil passage 422, and flows from the heat exchanger 105 to the engine 1 through the second oil passage 423. ENG oil flows toward. On the other hand, when the second switching valve 421 is in the closed state, the flow of ENG oil returning to the engine 1 via the heat exchanger 105 does not occur in the ENG oil circuit 420.

  Further, the ENG oil circuit 420 is provided with a second oil temperature sensor 153 that detects the temperature of the ENG oil (hereinafter, referred to as “ENG oil temperature”). The second oil temperature sensor 153 is installed in the ENG oil circuit 420 on the upstream side of the heat exchanger 105. Information on the ENG oil temperature Toil detected by the second oil temperature sensor 153 is input to the control device 150 as a detection signal.

[6. Control device]
The control device 150 controls the first switching valve 411 and the second switching valve 421 based on the detection signals (T / M oil temperature Ttm, ENG cooling water temperature Thw, ENG oil temperature Toil) input from the sensors 151 to 153. Controls opening and closing operations. That is, the control device 150 controls the heat exchange state of the heat exchanger 105 by performing switching control for switching the open / close state of the first switching valve 411 and the second switching valve 421. Specifically, the control device 150, T / M oil temperature Ttm, predetermined oil temperature _Ttm _1 for T / M oil temperature Ttm, ENG coolant temperature Thw, predetermined water temperature _Thw _1 for ENG coolant temperature Thw, ENG oil temperature Switching control is performed by comparing the Toils.

Predetermined oil temperature _{Ttm _1} is a value set in consideration of the T / M unit loss. The T / M unit is a drive device (first motor 2, second motor 3, power transmission mechanism) housed in transaxle case 40, and an electric system (such as inverter 21) connected to each of motors 2 and 3. including. Therefore, in the TM unit loss, in addition to the iron loss and the copper loss generated when each of the motors 2 and 3 is driven, a loss generated in the power transmission mechanism (for example, a loss generated in the lubrication required portion 30 due to drag resistance of oil). included. Further, the T / M unit loss has a characteristic (temperature characteristic) that its magnitude changes as the T / M oil temperature Ttm changes.

FIG. 7 is a diagram for explaining the relationship between the T / M unit loss and the T / M oil temperature Ttm. As shown in FIG. 7, if the T / M oil temperature Ttm is included in the low oil temperature range than the predetermined oil temperature Ttm _{_1,} the T / M unit loss as T / M oil temperature Ttm rises with the lapse of time Reduce continuously. Conversely, when the T / M oil temperature Ttm is included in the high oil temperature range than the predetermined oil temperature Ttm _{_1} is, T / M unit loss as is with oil temperature over time rises increases continuously. Therefore, the size of the T / M unit loss due to T / M oil temperature Ttm is a minimum value in the predetermined oil temperature _{Ttm _1.} This is because T / M unit loss can be classified into friction loss and motor loss, and friction loss is reduced by an increase in oil temperature, and motor loss is increased by an increase in oil temperature. Therefore, the control unit 150 uses a predetermined oil temperature _{Ttm _1} for T / M oil temperature Ttm the threshold, performing the switching control of the switching valves 411 and 421 (heat exchange control in the heat exchanger 105).

FIG. 8 is a diagram showing a temperature transition of the liquid in the normal traveling state. The normal running state is a state in which the vehicle is running with the power of the engine 1. As shown in FIG. 8, when the vehicle Ve is in the normal traveling state, the temperature of the liquid has a magnitude relation of “T / M oil temperature Ttm <ENG oil temperature Toil <ENG cooling water temperature Thw”. Further, when the ENG coolant temperature Thw rises above a predetermined temperature _{Thw _1,} fuel control for the engine 1 (hereinafter referred to as "ENG fuel control") is carried out all. That is, the predetermined water temperature _{Thw _1} is the threshold. The ENG fuel efficiency control is control performed for the purpose of improving fuel efficiency. For example, control for automatically stopping the engine 1 during a temporary stop, control for setting the operating point (engine speed, engine torque) of the engine 1 on the optimal fuel efficiency line with the highest efficiency, and running with the power of the motors 2 and 3 The ENG fuel efficiency control includes, for example, EV traveling control for permitting EV traveling. Although not shown in FIG. 8, in the high load traveling state, the ENG oil temperature Toil is higher than the T / M oil temperature Ttm and the ENG cooling water temperature Thw. For example, after the normal running state shown in FIG. 8 is continued for a long time (for example, several hours), the state becomes the high-load running state. Note that the normal traveling state includes HV traveling in which the vehicle travels using the power of the engine 1 and each of the motors 2 and 3, and engine traveling in which the vehicle travels using only the power of the engine 1.

[7. Heat exchange control]
FIG. 9 is a flowchart illustrating an example of the heat exchange control. The control routine shown in FIG. 9 is performed by the control device 150.

As shown in FIG. 9, the control unit 150 determines whether the T / M oil temperature Ttm is lower than the predetermined oil temperature _{Ttm _1} (step S1). Predetermined oil temperature Ttm _{_1} is preset threshold.

If T / M oil temperature Ttm is affirmative determination in step S1 by lower than the predetermined oil temperature _{Ttm _1} (Step S1: Yes), the control device 150 heat exchanger 105 in order to warm the T / M oil (Step S2). In this case, the control unit 150 determines ENG coolant temperature Thw is whether higher than a predetermined temperature _{Thw _1} (step S3). Predetermined water temperature _{Thw _1} is preset threshold.

If ENG coolant temperature Thw is affirmative determination in step S3 by higher than a predetermined temperature _{Thw _1} (Step S3: Yes), the controller 150 turns ON the ON and the second switching valve 421 of the first switching valve 411 (Step S4). When step S4 is performed, the first switching valve 411 and the second switching valve 421 are opened, so that heat exchange is performed between the T / M oil and the ENG cooling water, and the T / M oil and the ENG oil are exchanged. And heat exchange is performed. The control device 150 terminates the control routine after performing step S4.

  As described above, when the determination is affirmative in step S3, the ENG cooling water temperature Thw and the ENG oil temperature Toil are higher than the T / M oil temperature Ttm as shown in FIG. 8 described above. Then, when step S4 is performed, the heat of the ENG cooling water and the ENG oil moves to the T / M oil, and the T / M oil is warmed. Therefore, the T / M oil can be warmed early by the heat of the ENG cooling water and the heat of the ENG oil. Thus, the lubrication-required portion 30 can be warmed up early by the T / M oil that has passed through the heat exchanger 105.

If ENG coolant temperature Thw is negatively determined in step S3 by equal to or less than a predetermined temperature _{Thw _1} (step S3: No), or the control unit 150 T / M oil temperature Ttm is lower than the ENG oil temperature Toil It is determined whether or not it is (step S5).

  When the T / M oil temperature Ttm is lower than the ENG oil temperature Toil and the determination in step S5 is affirmative (step S5: Yes), the control device 150 turns off the first switching valve 411 and turns off the second switching valve 421. Is turned ON (step S6). When step S6 is performed, the second switching valve 421 is opened to perform heat exchange between the T / M oil and the ENG oil, but the first switching valve 411 is closed so that the T / M oil and the ENG oil are exchanged. No heat exchange takes place with the cooling water. The control device 150 terminates the control routine after performing step S6.

As described above, when step S6 is performed after the determination in step S5, the T / M oil temperature Ttm is lower than the ENG oil temperature Toil. The T / M oil moves to the oil and is warmed. Therefore, the T / M oil can be quickly warmed by the heat of the ENG oil. Thus, the lubrication-required portion 30 can be warmed up early by the T / M oil that has passed through the heat exchanger 105. Further, if the step S6 is carried out after the determination in step S5, since the ENG cooling water does not give heat to T / M oil, ENG coolant to ENG coolant temperature Thw is increased to a predetermined temperature _{Thw _1} is Heated preferentially. As a result, the engine 1 is warmed up by the ENG cooling water.

  If the T / M oil temperature Ttm is equal to or higher than the ENG oil temperature Toil and a negative determination is made in step S5 (step S5: No), the control device 150 switches the first switching valve 411 and the second switching valve 421. Control is turned off (step S7). When step S7 is performed, since the first switching valve 411 and the second switching valve 421 are closed, heat exchange does not occur between the T / M oil and the ENG cooling water or between the T / M oil and the ENG oil. Not done. That is, the T / M oil does not receive heat from the ENG cooling water or the ENG oil. After performing step S7, control device 150 ends the control routine.

  As described above, when step S7 is performed after the determination in step S5, since the T / M oil temperature Ttm is higher than the ENG oil temperature Toil, the T / M oil temperature is reduced by closing the second switching valve 421. To prevent heat from being transferred to the ENG oil. This prevents the heat of the T / M oil from being taken away by the ENG oil when the T / M oil is warmed. Therefore, the lubrication-required portion 30 can be quickly warmed up by the T / M oil that has passed through the heat exchanger 105.

On the other hand, if the T / M oil temperature Ttm is negatively determined in step S1 by the predetermined oil temperature _{Ttm _1} more (step S1: No), the control device 150 heat in order to cool the T / M oil The cooling control for controlling the heat exchange state in the exchanger 105 is performed (step S8). In this case, control device 150 determines whether or not ENG oil temperature Toil is lower than ENG cooling water temperature Thw (step S9).

  When the ENG oil temperature Toil is lower than the ENG cooling water temperature Thw and the determination in step S9 is affirmative (step S9: Yes), the control device 150 determines whether the T / M oil temperature Ttm is lower than the ENG oil temperature Toil. It is determined whether or not it is (step S10).

  If the T / M oil temperature Ttm is lower than the ENG oil temperature Toil and the determination is positive in step S10 (step S10: Yes), the control device 150 performs the above-described step S7 and executes the first switching valve 411. And the second switching valve 421 is controlled to be OFF.

  As described above, when step S7 is performed after the determination in step S10, the T / M oil temperature Ttm is lower than the ENG cooling water temperature Thw and the ENG oil temperature Toil. Closing the switching valve 421 can prevent the heat of the ENG cooling water from moving to the T / M oil and prevent the heat of the ENG oil from moving to the T / M oil. Thereby, when cooling the T / M oil, it is possible to prevent the T / M oil from being heated by the ENG cooling water and the ENG oil, so that the cooling property of the T / M oil can be ensured.

  If the T / M oil temperature Ttm is equal to or higher than the ENG oil temperature Toil and a negative determination is made in step S10 (step S10: No), the control device 150 performs the above-described step S6 and executes the first switching valve 411. Is turned off and the second switching valve 421 is turned on.

  As described above, when step S6 is performed after the determination in step S10, since the T / M oil temperature Ttm is higher than the ENG oil temperature Toil, the ENG cooling water is closed by closing the first switching valve 411. The heat can be prevented from being transferred to the T / M oil, and the heat of the T / M oil can be transferred to the ENG oil by opening the second switching valve 421. Thereby, when cooling the T / M oil, it is possible to prevent the T / M oil from being warmed by the ENG cooling water and to cool the T / M oil with the ENG oil. Nature can be secured.

  When the ENG oil temperature Toil is equal to or higher than the ENG cooling water temperature Thw and the determination in step S9 is negative (step S9: No), the control device 150 determines whether the T / M oil temperature Ttm is lower than the ENG cooling water temperature Thw. It is determined whether or not it is (step S11).

  When the T / M oil temperature Ttm is lower than the ENG cooling water temperature Thw and the determination in step S11 is affirmative (step S11: Yes), the control device 150 performs the above-described step S7 and executes the first switching valve 411. And the second switching valve 421 is controlled to be OFF.

  As described above, when step S7 is performed after the determination in step S11, the temperature of each liquid satisfies the magnitude relationship of “T / M oil temperature Ttm <ENG cooling water temperature Thw ≦ ENG oil temperature Toil”. Therefore, closing the first switching valve 411 and the second switching valve 421 can prevent the heat of the ENG cooling water from moving to the T / M oil and prevent the heat of the ENG oil from moving to the T / M oil. Thereby, when cooling the T / M oil, it is possible to prevent the T / M oil from being heated by the ENG cooling water and the ENG oil, and it is possible to ensure the cooling property of the T / M oil.

  If the T / M oil temperature Ttm is equal to or higher than the ENG cooling water temperature Thw and a negative determination is made in step S11 (step S11: No), the control device 150 turns on the first switching valve 411 and turns on the second switching valve 421. Is turned off (step S12). When step S12 is performed, heat exchange is performed between the T / M oil and the ENG cooling water because the first switching valve 411 is opened, but because the second switching valve 421 is closed, the T / M oil and the E / C oil are closed. No heat exchange takes place with ENG oil. After performing step S12, control device 150 ends the control routine.

  As described above, when a negative determination is made in step S11, since the T / M oil temperature Ttm is higher than the ENG cooling water temperature Thw, the heat of the T / M oil is reduced by opening the first switching valve 411. The heat of the ENG oil is prevented from being transferred to the T / M oil by closing the second switching valve 421 while being moved to the ENG cooling water. Thereby, when cooling the T / M oil, the T / M oil can be cooled by radiating heat to the ENG cooling water, and the T / M oil can be prevented from being warmed by the ENG oil. Can be secured.

[8. Comparison with Reference Example]
Here, in order to explain the superiority of the cooling device 100 of the second embodiment, the cooling device 100 is compared with a reference example with reference to FIG. Note that, regarding the cooling device 500 illustrated in FIG. 11, the description of the same configuration as the cooling device 300 illustrated in FIG.

  FIG. 11 is a schematic diagram illustrating a schematic configuration of a cooling device 500 of a reference example. As shown in FIG. 11, the cooling device 500 of the reference example does not include the above-described heat exchanger 105. That is, in the cooling device 500, heat exchange is not performed between the T / M oil and the liquid on the engine 1 side (the ENG cooling water in the ENG cooling circuit 410 and the ENG oil in the ENG oil circuit 420). For this reason, in the cooling device 500, the T / M oil cannot be heated by the liquid (ENG cooling water, ENG oil) on the engine 1 side when the lubrication requiring unit 30 is warmed up, and the temperature rise of the T / M oil is delayed. Would. Therefore, in the normal traveling state, there is a possibility that the agitation loss and the drag loss generated in the lubrication requiring portion 30 increase. Further, in a high-load running state, the cooling performance of the T / M oil is reduced, so that the loss (copper loss and iron loss) of the motor system may increase.

  Advantages of the second embodiment include warm-up performance and fuel efficiency, in addition to advantages (cooling performance and structure) similar to those of the above-described first embodiment. According to the second embodiment, at the time of warm-up, heat exchange is performed between the liquid (ENG cooling water, ENG oil) on the engine 1 side and the T / M oil, so that the T / M oil temperature Ttm increases. It becomes early, and it becomes possible to complete warm-up early. Thereby, the agitation loss and the drag loss (T / M friction) in the lubrication required portion 30 can be reduced, and the fuel efficiency can be improved.

  Further, by performing the switching control in consideration of the ENG cooling water temperature Thw, it is possible to minimize the friction in the engine 1 (hereinafter referred to as “ENG friction”) and the adverse effect on the ENG fuel efficiency control. Further, when comparing the oil temperature sensitivity of ENG friction with ENG oil and the oil temperature sensitivity of T / M friction with T / M oil, the oil temperature sensitivity of T / M friction is larger than the oil temperature sensitivity of ENG friction. Therefore, when the ENG oil temperature Toil is higher than the T / M oil temperature Ttm, when the heat of the ENG oil is transferred to the T / M oil, the T / M friction is reduced, so that the fuel efficiency can be improved. . Note that the ENG friction is reduced by increasing the ENG oil temperature Toil.

  As described above, by reducing the pressure loss due to the T / M oil and expanding the operating limit oil temperature range of the electric oil pump 102, it is possible to sufficiently secure the flow rate of the T / M oil (secure the necessary flow rate) and to reduce the electric oil. The degree of freedom of the pump 102 is improved. Thereby, the oil circulation circuit 200 having a circuit configuration in which the inverter circuit and the transaxle oil passage are integrated is made possible.

  As described above, according to the second embodiment, in addition to the effects of the above-described first embodiment, the T / M oil can be warmed early, and the warm-up of the power transmission mechanism is completed early. T / M friction is reduced and fuel efficiency can be improved.

  The vehicle cooling device according to the present invention is not limited to the above-described second embodiment, and can be appropriately changed without departing from the purpose of the present invention.

  For example, each of the switching valves 411 and 421 is not limited to an electromagnetic valve, and may be configured by an ON-OFF valve that can be controlled by the control device 150.

  Further, the first oil temperature sensor 151 may be provided in the lubrication circuit 220 on the upstream side of the heat exchanger 105. For example, the first oil temperature sensor 151 is provided in the oil storage unit 104, and may detect the temperature Ttm of the T / M oil stored in the oil storage unit 104. Similarly, the location of the water temperature sensor 152 is not particularly limited as long as it is located upstream of the heat exchanger 105 in the ENG cooling circuit 410. The location of the second oil temperature sensor 153 is not particularly limited as long as it is located upstream of the heat exchanger 105 in the ENG oil circuit 420.

1 engine 2 1st motor (MG1)
3 Second motor (MG2)
Reference Signs List 21 inverter 30 lubrication required part 40 transaxle case 100 cooling device (vehicle cooling device)
101 mechanical oil pump (second oil pump)
102 Electric oil pump (first oil pump)
103 HV radiator (oil cooler)
104 oil storage unit 105 three-phase heat exchanger 150 control unit (ECU)
151 first oil temperature sensor 152 water temperature sensor 153 second oil temperature sensor 200 oil circulation circuit 201 first discharge oil path 202 first supply oil path 203 second supply oil path 203a MG1 cooling pipe 203b MG2 cooling pipe 204 third supply oil Road 205 Air-cooled oil passage 206 Second discharge oil passage 207 Fourth supply oil passage 210 First circuit (cooling circuit)
220 Second circuit (lubrication circuit)
410 ENG cooling circuit 411 First switching valve 420 ENG oil circuit 421 Second switching valve Ve Vehicle

Claims (8)

An electric motor, an inverter electrically connected to the electric motor, and a power transmission mechanism for transmitting power output from the electric motor to wheels, mounted on a vehicle including:
In a vehicle cooling device including an oil circulation circuit having an oil storage portion,
The oil circulation circuit,
A first oil pump that sucks oil stored in the oil storage unit and discharges the oil as a refrigerant supplied to the inverter and the electric motor; and a first oil pump and the first oil pump and the inverter or the electric motor. An oil cooler provided between the inverter and an oil cooler that cools the oil supplied to the inverter and the electric motor;
A second oil pump that sucks the oil stored in the oil storage unit and discharges the oil supplied to a lubrication-requiring unit included in the power transmission mechanism without passing through the oil cooler. possess a circuit, the,
Mounted on a vehicle including the electric motor and the engine as a power source,
The first oil pump is an electric oil pump driven by an electric motor,
The second oil pump is a mechanical oil pump driven by the engine,
The second circuit is capable of exchanging heat between engine cooling water and the oil discharged from the second oil pump, and exchanging heat between engine oil and the oil discharged from the second oil pump. Further comprising a three-phase heat exchanger configured as possible,
An open state in which the engine cooling water is circulated, in which the engine cooling water can flow through the heat exchanger, and in which the engine cooling water cannot flow through the heat exchanger. A first switching valve that switches between a closed state and a closed state;
An open state in which the engine oil can flow through the heat exchanger, and a closed state in which the engine oil cannot flow through the heat exchanger. And a second switching valve for switching between the two . The said 1st circuit WHEREIN: The said inverter and the said electric motor are connected in series downstream of the said 1st oil pump, The said electric motor is provided in the downstream of the said inverter. The vehicle cooling device according to claim 1. 2. The vehicle cooling device according to claim 1, wherein in the first circuit, the inverter and the electric motor are connected in parallel on a downstream side of the first oil pump. 3.   4. The vehicle cooling device according to claim 1, wherein the inverter is configured to allow the oil discharged from the first oil pump to flow inside as a refrigerant. 5.   The vehicle cooling device according to any one of claims 1 to 4, wherein the oil cooler is an air-cooled oil cooler that performs heat exchange between the oil and air. A first oil temperature sensor for detecting a temperature of the oil,
A water temperature sensor for detecting a temperature of the engine cooling water,
A second oil temperature sensor for detecting a temperature of the engine oil,
Said first oil temperature sensor thus detected temperature of the oil, the water temperature sensor of the engine cooling water detected by the temperature, based on the temperature of the engine oil detected by the second oil temperature sensor, wherein A control device for controlling opening and closing operations of the first switching valve and the second switching valve;
Further comprising
When the temperature of the oil is lower than a predetermined oil temperature, the control device controls at least the second switching valve of the first switching valve and the second switching valve to be in an open state, and the heat exchanger The vehicle cooling device according to any one of claims 1 to 5, wherein warm-up control is performed to increase the temperature of the oil by heat exchange in the vehicle. When performing the warm-up control, the control device controls the first switching valve and the second switching valve to be in an open state when a temperature of the engine cooling water is higher than a predetermined water temperature. The vehicle cooling device according to claim 6 . The control device, when performing the warm-up control, when the temperature of the engine cooling water is equal to or lower than a predetermined water temperature, and when the temperature of the oil is lower than the temperature of the engine oil, the first switching to control the valve in the closed state and the vehicular cooling apparatus according to claim 6 or 7, wherein the controller controls the second switching valve in the open state.

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