RU2652469C1 - Vehicle cooling system - Google Patents

Abstract

FIELD: cooling.

SUBSTANCE: invention refers to the vehicle cooling system. Cooling system, which includes the oil circulation circuit, the first circuit, including the electric oil pump, which discharges oil as a coolant, which is supplied to the inverter and to the corresponding motors, and to the HV radiator, which cools the oil that is supplied to the inverter and the respective motors, and the second circuit that comprises the mechanical oil pump, which emits oil that is fed into the lubricating part, without passing through the HV-radiator.

EFFECT: invention allows to reduce the dimensions of the cooling system that provides for the cooling and lubrication performance values.

12 cl, 11 dwg

Description

State of the art

1. The technical field to which the invention relates.

[0001] The present disclosure relates to a vehicle cooling system.

2. Description of the Related Art

[0002] As cooling systems for hybrid vehicles with an engine and electric motors installed therein, inverter cooling circuits are known for cooling an inverter electrically connected to electric motors. It is known that the inverter cooling circuits circulate cooling water (hybrid cooling water) as a cooling medium.

[0003] In addition, it is well known that engine cooling circuits using cooling water (engine cooling water), which is different from hybrid cooling water, as a cooling agent. Publication of a patent application (Japan) No. 2013-199853 discloses a cooling system including an engine cooling circuit and a transaxle cooling circuit using an oil as a coolant in which heat exchange between cooling water for an engine and oil is carried out by means of a heat exchanger.

SUMMARY OF THE INVENTION

[0004] In a hybrid vehicle, a cooling system may be installed including an inverter cooling circuit, an engine cooling circuit, and a bridge-gearbox cooling circuit. In the respective cooling circuits mentioned above, special fluids, such as hybrid cooling water, engine cooling water and oil, circulate in their respective independent flow channels. Thus, the number of parts included in the respective cooling circuits is large, and the cooling system has a large overall size.

[0005] In addition, in the cooling circuit of the axle-gearbox assembly described in JP 2013-199853 A, a part requiring oil lubrication or oil heating (a part requiring lubrication) and a part requiring oil cooling (a cooling part) are included in the housing of the axle-gearbox assembly, which is an oil delivery destination assembly. To reduce the resistance to oil mixing, it is necessary to supply warm oil, for example, to the gears of the transmission, which are included in the part requiring lubrication. On the other hand, it is necessary to supply low temperature oil to the electric motors, which are included in the cooling part to cool the electric motors.

[0006] However, in the configuration in JP 2013-199853 A, oil in the cooling circuit of the axle-gearbox assembly is supplied to the lubricating part and to the cooling part in the housing of the axle-gearbox assembly without discrimination. Thus, if cooling takes precedence over lubrication, the part to be heated (the part requiring lubrication) also cools simultaneously with the part to be cooled (the part requiring cooling). On the other hand, if the lubricant has a higher priority with respect to cooling, the part to be cooled (the part to be cooled) also heats up simultaneously with the part to be heated (the part requiring lubrication).

[0007] The present disclosure provides a vehicle cooling system that reduces the size of a cooling system and provides both cooling performance and lubricant performance.

[0008] A vehicle cooling system according to an aspect of the present disclosure is installed in a vehicle including an electric motor, an inverter electrically connected to an electric motor, and a power transmission mechanism that transmits driving power output from the electric motor to the wheel. The vehicle cooling system includes an oil circuit. The oil circulation circuit includes: an oil accumulation section; a first circuit including a first oil pump that draws in oil accumulated in the oil storage section, and discharges oil as a coolant to be supplied to the inverter and the electric motor, and an oil cooler provided between the first oil pump and the inverter or electric motor, moreover, the oil cooler cools the oil, which must be supplied to the inverter and the electric motor; and a second circuit including a second oil pump that draws in oil accumulated in the oil storage section, and discharges oil, which is to be supplied to a lubricating part included in the power transfer mechanism without passing through the oil cooler.

[0009] According to the above aspect, only oil circulates in the oil circulation circuit including an inverter and an electric motor. Therefore, the size of the vehicle cooling system may be reduced. In addition, as a cooling circuit, the first circuit cools the oil discharged from the first oil pump through an oil cooler and supplies oil to an inverter or electric motor. As a lubricant circuit, the second circuit delivers oil discharged from the second oil pump to a part requiring lubrication without cooling the oil by means of an oil cooler. Therefore, both cooling performance and lubricant performance can be provided.

[0010] In the above aspect, in the first circuit, an inverter and an electric motor can be provided on the discharge side of the first oil pump, an inverter and an electric motor can be connected in series, and an electric motor can be provided on the discharge side of the inverter.

[0011] According to the above aspect, the first circuit includes an inverter between the oil cooler and the electric motor on the exhaust side of the first oil pump. If the electric motor and the inverter are compared in terms of heat-resistant temperature, the heat-resistant temperature of the inverter is lower. According to the cooling system, the first circuit enables the supply of oil, cooled by means of an oil cooler, to the inverter before the electric motor.

[0012] In the above aspect, in the first circuit, an inverter and an electric motor can be provided on the discharge side of the first oil pump, and the inverter and the electric motor can be connected in parallel.

[0013] According to the present aspect, the first circuit enables oil cooled by the oil cooler to be supplied to the electric motor without oil passing through the inverter on the discharge side of the first oil pump. Therefore, the temperature of the oil to be supplied to the electric motor does not increase as a result of heat exchange with the inverter, providing the possibility of cooling the electric motor through low-temperature oil.

[0014] In the above aspect, the electric motor may include a stator and a rotor, and in a first circuit, a cooling pipe of an electric motor for supplying oil to the electric motor may include an outlet for discharging oil into the stator. In addition, oil flowing in the primary circuit may have an insulating property.

[0015] In the above aspect, the inverter may be configured such that oil discharged from the first oil pump flows internally as a coolant.

[0016] According to the above aspect, the inside of the inverter can be cooled by oil discharged from the first oil pump. Therefore, the cooling performance for the inverter is improved, and the heat resistance performance of the inverter is also improved.

[0017] In the above aspect, the oil cooler may be an air-cooled oil cooler that causes heat exchange between the oil and air.

[0018] According to the above aspect, the oil discharged from the first oil pump is cooled by an air-cooled oil cooler, and therefore, the cooling ability of the oil is improved.

[0019] A vehicle cooling system according to the above aspect may be installed in a vehicle including an electric motor and an engine as sources of driving power. The first oil pump may be an electric oil pump that must be driven by an electric motor, and the second oil pump may be a mechanical oil pump that must be driven by a motor.

[0020] According to the above aspect, the first oil pump is formed from an electric oil pump, and therefore even if the engine is stopped, the first oil pump can be driven. In addition, the amount of discharge from the first oil pump can be controlled by a control module, such as an electronic control module.

[0021] In the above aspect, the second circuit may further include a three-phase heat exchanger configured to permit heat exchange between the engine cooling water and oil discharged from the second oil pump, and allows heat exchange between the engine oil and oil discharged from the second oil pump.

[0022] According to the above aspect, a three-phase heat exchanger allows heat exchange between the engine cooling water and oil discharged from the second oil pump, and also allows heat exchange between the engine oil and oil discharged from the second oil pump. Therefore, the oil that passes through the three-phase heat exchanger can be supplied to the part requiring lubrication.

[0023] In the above aspect, the vehicle cooling system may further include a first switching valve provided in a circuit in which cooling water for the engine circulates, the first switching valve switching between an open state in which the cooling water flow for the engine through the heat exchanger is allowed and a closed state in which the flow of cooling water for the engine through the heat exchanger is not permitted; and a second switching valve provided in a circuit in which engine oil circulates, the second switching valve switching between an open state in which the oil flow to the engine through the heat exchanger is allowed and a closed state in which the oil flow to the engine through the heat exchanger is not allowed.

[0024] According to the above aspect, the heat transfer state in the three-phase heat exchanger can be controlled by switching each of the first switching valve and the second switching valve between open and closed states.

[0025] In the above aspect, the vehicle cooling system may further include: a first oil temperature sensor that senses an oil temperature; a water temperature sensor that detects the temperature of the cooling water for the engine; a second oil temperature sensor that senses an oil temperature for the engine; and a control module that controls the opening-closing of each of the first switching valve and the second switching valve based on the oil temperature detected by the first oil temperature sensor, the engine cooling water temperature detected by the water temperature sensor, and the engine oil temperature determined by second oil temperature sensor. The control module may be configured to, when the oil temperature is below a predetermined oil temperature, control at least a second switching valve among the first switching valve and the second switching valve so that it is in the open state, and perform heating control such so as to increase the temperature of the oil through heat transfer in the heat exchanger.

[0026] According to the above aspect, the oil supplied to the lubricating part takes heat from at least one of the cooling water for the engine and the oil for the engine and is therefore heated. Thus, the increase in oil temperature is accelerated, providing quick heating of the lubricating part. Consequently, the loss of resistance to sliding and / or the loss of resistance to agitation caused in the lubricating part by means of oil can be reduced, thereby increasing fuel efficiency.

[0027] In the above aspect, the control module may be configured, if the control module performs heating control when the temperature of the cooling water for the engine is higher than the predetermined water temperature, to control the first switching valve and the second switching valve so that they are in open states.

[0028] According to the above aspect, the oil supplied to the lubricating part receives heat of cooling water for the engine and the oil for the engine and is therefore heated, and therefore, the temperature increase of the oil is accelerated, allowing the part to be lubricated to be heated quickly. Consequently, the loss of resistance to sliding and / or the loss of resistance to agitation caused in the lubricating part by means of oil can be reduced, thereby increasing fuel efficiency. In addition, the switching state of the heat transfer in the three-phase heat exchanger is performed taking into account the temperature of the cooling water for the engine, suppressing the negative effect on the engine side caused by heat transfer in the heat exchanger.

[0029] In the above aspect, the control module may be configured, if the control module performs heating control, when the temperature of the cooling water for the engine is equal to or lower than the predetermined water temperature and the oil temperature is lower than the temperature of the oil for the engine, to control the first switching valve so that it is in the closed state and control the second switching valve so that it is in the open state.

[0030] According to the above aspect, the switching state of the heat transfer in the three-phase heat exchanger is performed taking into account the temperature of the cooling water for the engine, suppressing the negative effect on the engine side caused by heat transfer in the heat exchanger. In other words, when the temperature of the cooling water for the engine is lower than a predetermined temperature of the water, and therefore the heating of cooling water for the engine is required, the first switching valve is closed even during the heating control to heat the oil in the second circuit, suppressing heat recovery by the oil in second circuit of cooling water for the engine.

[0031] In the above aspect, the oil circuit includes a first circuit (cooling circuit) including an inverter and an electric motor, and a second circuit (lubricant circuit) including a part requiring lubrication. Since the oil circulation circuit only circulates oil, the size of the vehicle cooling system can be reduced compared to ordinary cases in which the inverter cooling circuit that circulates the cooling water and the cooling circuit of the axle-gearbox assembly that circulates the oil, are separate from each other. In addition, the first circuit can supply oil, cooled by means of an oil cooler, to the inverter and electric motor, and the second circuit can supply oil, which does not pass through the oil cooler, to the part requiring lubrication. Therefore, the cooling system can provide both cooling performance and lubricant performance.

Brief Description of the Drawings

[0032] The following describes the features, advantages and technical and industrial significance of exemplary embodiments of the disclosure with reference to the accompanying drawings, in which like numbers denote like elements and in which:

FIG. 1 is a circuit diagram illustrating an example of a vehicle with a vehicle cooling system installed therein;

FIG. 2 is a circuit diagram illustrating a schematic configuration of a cooling system according to a first embodiment;

FIG. 3 is a diagram for describing a comparison between the kinetic viscosity of an oil used in a cooling system according to a first embodiment and the kinetic viscosity of a conventional oil;

FIG. 4 is a diagram for describing a relationship between a pump discharge amount and an oil temperature;

FIG. 5 is a circuit diagram illustrating a schematic configuration of a cooling system according to a modification;

FIG. 6 is a circuit diagram illustrating a schematic configuration of a cooling system according to a second embodiment;

FIG. 7 is a diagram for describing the relationship between losses in the T / M block and the temperature of the T / M oil;

FIG. 8 is a diagram illustrating changes in fluid temperature in a normal state of motion;

FIG. 9 is a flowchart illustrating an example of a heat transfer control flowchart in a second embodiment;

FIG. 10 is a circuit diagram illustrating a schematic configuration of a cooling system according to a comparative example; and

FIG. 11 is a diagram for describing a cooling system according to another comparative example.

Detailed Description of Embodiments

[0033] The vehicle cooling system according to an embodiment of the present disclosure is described in detail below with reference to the drawings.

[0034] First Embodiment

1. Vehicle

FIG. 1 is a circuit diagram illustrating an example of a vehicle with a vehicle cooling system installed therein. Vehicle Ve is a hybrid vehicle including an engine 1, a first motor 2 (MG1) and a second motor 3 (MG2) as sources of driving power. Engine 1 is a well-known internal combustion engine. Motors 2, 3 are well-known motor generators having a motor function and a power generation function. The respective motors 2, 3 are electrically connected to the battery 22 through the inverter 21. In addition, the corresponding motors 2, 3 are included in the cooling part in the housing 40 of the bridge-gearbox assembly. The inverter 21 is located outside the housing 40 of the node "bridge-gearbox".

[0035] The Ve vehicle includes a power sharing mechanism 5 in a power transmission path from an engine 1 to wheels 4 (drive wheels). In the vehicle Ve, the driving power outputted by the engine 1 is divided on the side of the first motor 2 and on the side of the wheels 4 by the power sharing mechanism 5. At this time, the first motor 2 generates electricity using the driving power output by the engine 1, and the electric energy is stored in the battery 22 or supplied to the second motor 3 through the inverter 21.

[0036] The input shaft 6, the power sharing mechanism 5, and the first motor 2 are coaxial with the crankshaft of the engine 1. The crankshaft and the input shaft 6 are connected through an un illustrated torque limiter or the like. The first motor 2 is located next to the power sharing mechanism 5 on the side opposite the motor 1 in the axial direction. The first motor 2 includes a stator 2a around which a coil, a rotor 2b and a rotor shaft 2c are wound.

[0037] The power sharing mechanism 5 is a differential mechanism including a plurality of rotational elements, and in the example illustrated in FIG. 1 is formed by a single satellite type planetary gear. The power sharing mechanism 5 includes a sun gear 5S, which is an external gear, a ring gear 5R, which is an internal gear, concentrically arranged with the sun gear 5S, and a carrier 5C, which holds the satellite gear, meshing with the sun gear 5S and the ring gear 5R so that the satellite gear can rotate, and can also revolve around the sun gear 5S, as three rotational elements.

[0038] The rotor shaft 2c of the first motor 2 is connected to the sun gear 5S so that it rotates as a unit with the sun gear 5S. The input shaft 6 is connected to the carrier 5C so that it rotates as a unit with the carrier 5C. The engine 1 is connected to the carrier 5C through the input shaft 6. The output gear 7, which outputs the torque from the power separation mechanism 5 to the side of the wheels 4, is integrated with the ring gear 5R. The output gear 7 is an external gear, which rotates as a unit with the ring gear 5R and engages with the driven gear of the return shaft 8b for the gear mechanism 8 of the return shaft.

[0039] The output gear 7 is connected to the differential gear 9 through the gear mechanism 8 of the reverse shaft. The reverse shaft gear mechanism 8 includes a reverse shaft 8a parallel to the input shaft 6, a driven gear 8b of the return shaft engaged with the output gear 7, and a driving gear 8c of the reverse shaft engaged with the ring gear 9a of the differential gear 9. The driven gear The return shaft 8b and the return shaft driving gear 8c are connected to the return shaft 8a so that they rotate as a unit. The wheels 4 are connected to the differential gear 9 through the right and left drive shafts 10.

[0040] The vehicle Ve is configured to summarize the torque output by the second motor 3 with the torque transmitted from the engine 1 to the wheels 4. The second motor 3 includes a stator 3a around which a coil, a rotor 3b and a shaft 3c are wound rotor. The rotor shaft 3c is parallel with the return shaft 8a. The gearbox 11 engaged with the driven gear 8b of the return shaft is connected to the rotor shaft 3c in such a way that it rotates as a unit with the rotor shaft 3c.

[0041] In addition, a mechanical oil pump 101 (MOP) is provided in the vehicle Ve, which is driven by the engine 1. The mechanical oil pump 101 is coaxial with the crankshaft of the engine 1 and includes a pump rotor (not illustrated), which rotates as a unit with input shaft 6. For example, if the vehicle Ve is driven forward by the driving power of engine 1, the pump rotor for the mechanical oil pump 101 is rotated forward by the input torque Nogo shaft 6, and a mechanical oil pump 101 produces oil from the outlet port. The oil discharged from the mechanical oil pump 101 is supplied to a lubricating part 30 (illustrated, for example, in FIG. 2) in the housing 40 of the axle-gearbox assembly and acts as a lubricating oil. The lubricating part 30 is part (mainly gears) of the vehicle power transmission mechanism Ve, the part requiring oil lubrication and oil heating in the housing 40 of the axle-gearbox assembly. The power transmission mechanism is a mechanism that transmits the driving power output from the driving power sources (engine 1, first motor 2 and second motor 3) of the vehicle Ve to the wheels 4. In the vehicle Ve, illustrated in FIG. 1, the lubricating portion 30 includes a power sharing mechanism 5, an output gear 7, and a reverse shaft gear mechanism 8.

[0042] 2. Cooling system

FIG. 2 is a circuit diagram illustrating a schematic configuration of a vehicle cooling system 100 according to a first embodiment. The vehicle cooling system 100 (hereinafter referred to simply as the "cooling system") is installed in the vehicle Ve, illustrated in FIG. 1, and is configured to cool the inverter 21 using transmission lubricating oil (T / M lubricating oil). In this description, a transmission lubricating oil (T / M lubricating oil) is simply referred to as “oil”.

[0043] As illustrated in FIG. 2, the cooling system 100 includes an oil circulation circuit 200 that circulates the oil. The oil circulation circuit 200 includes a first circuit 210 (hereinafter referred to as the "cooling circuit") for cooling the inverter 21 and the respective motors 2, 3, and a second circuit 220 (hereinafter referred to as the "lubrication circuit") for lubricating and heating the part to be lubricated thirty.

[0044] More specifically, the oil circulation circuit 200 has a structure in which an oil channel (inverter oil channel) that supplies oil to the inverter 21 as a coolant, and a cooling oil channel that supplies oil to a cooling portion in the assembly 40 of the assembly "bridge-gearbox", included in the oil channel of the node "bridge-gearbox", maintain communication with each other. In other words, only one and the same liquid, which is oil, circulates in the oil circulation circuit 200, which includes an inverter oil channel and an axle-gearbox oil channel. In addition, the cooling system 100 pumps oil in the oil circulation circuit 200 to the supply destinations by means of two oil pumps.

[0045] 2-1. Cooling circuit

The cooling circuit 210 includes an electric oil pump 102, which is the first oil pump, a hybrid radiator 103 only (hereinafter referred to as the “HV radiator"), an inverter 21, which is a target for cooling, respective motors 2, 3 which are targets for cooling, and an oil storage section 104. The cooling circuit 210 cools the oil discharged from the electric oil pump 102 by means of an HV radiator 103 and supplies oil to the inverter 21 and the respective motors 2, 3.

[0046] The electric oil pump 102 is driven by an electric motor (not illustrated). The electric motor is driven by a control unit 150 (ECU). The control unit 150 includes a well-known electronic control unit and controls the actuation of the electric oil pump 102. The electric oil pump 102, which is driven by the control unit 150, draws in the oil accumulated in the oil storage section 104 and discharges the oil from the outlet port. The electric oil pump 102 discharges oil supplied to the cooling target (inverter 21 and motors 2, 3) as a coolant. The first outlet oil channel 201 is connected to the outlet port of the electric oil pump 102. The oil discharged into the first outlet oil channel 201 by the electric oil pump 102 is pumped by the pressure at the outlet of the electric oil pump 102 to the inverter 21 and motors 2, 3, which are oil supply destination nodes in cooling circuit 210.

[0047] The HV radiator 103 is a heat exchanger that performs heat exchange between the oil flowing in the cooling circuit 210 and air (for example, air outside the vehicle Ve). In other words, the HV radiator 103 is an air-cooled oil cooler that is located outside the housing 40 of the axle-gearbox assembly. The oil flowing in the HV radiator 103 generates heat as a result of heat exchange with air outside the vehicle Ve. An HV radiator 103 is provided between the electric oil pump 102 and the inverter 21 and motors 2, 3 in the cooling circuit 210. The cooling circuit 210 cools the air (cools) the oil pumped from the electric oil pump 102 to the inverter 21 and the motors 2, 3 by means of an HV radiator 103. The first exhaust oil channel 201 is connected to the input of the HV radiator 103, and the first oil supply channel 202 connected to the output of the HV radiator 103.

[0048] The first oil supply channel 202 is an oil channel between the HV radiator 103 and the inverter 21, the oil channel allowing air-cooled oil to be supplied by the HV radiator 103 to the inverter 21. The first oil supply channel 202 is connected to the input of the casing inverter 21. Oil cooled by air by means of an HV radiator 103 flows into the casing of the inverter 21 from the first oil supply channel 202, contacts the heat-generating part of the inverter 21 and performs direct heat exchange with the heat-generating part, s and due to this, cooling the inverter 21.

[0049] The second oil supply channel 203 is connected to the output of the casing of the inverter 21. The second oil supply channel 203 is an oil channel between the inverter 21 and the motors 2, 3, the oil channel allowing the supply of oil cooled by air through the HV radiator 103 to respective motors 2, 3. In the cooling circuit 210, the inverter 21 and the respective motors 2, 3 are connected in series on the discharge side of the electric oil pump 102, and the corresponding motors 2, 3 are provided on the discharge side of the inverter 21. The corresponding motors 2, 3 are located in the housing 40 of the axle-gearbox assembly, and therefore, the oil that must be supplied to the respective motors 2, 3 temporarily flows outside the housing 40 of the axle-gearbox assembly when passing through the HV radiator 103 and inverter 21.

[0050] Furthermore, in the example illustrated in FIG. 2, the second supply oil channel 203 is an oil channel that branches on the outlet side. The second oil supply passage 203 includes a cooling pipe 203a MG1 and a cooling pipe 203b MG2. The cooling pipe 203a MG1 forms one branch oil channel and delivers the oil to the first motor 2. The cooling pipe 203b MG2 forms the other branch oil channel and supplies the oil to the second motor 3. More specifically, for cooling, in particular, the stator 2a, which generates heat when by supplying power to the first motor 2, the cooling pipe 203a of MG1 has a structure including an outlet for discharging oil into the stator 2a. To cool, in particular, the stator 3a, which generates heat when power is supplied to the second motor 3, the cooling pipe 203b MG2 has a structure including an outlet for discharging oil into the stator 3a. Corresponding cooling pipes 203a, 203b are located in the housing 40 of the axle-gearbox assembly.

[0051] The oil flowing from the electric oil pump 102 to the respective motors 2, 3 in the oil cooling circuit 210 cools the respective motors 2, 3 and then flows to the oil storage section 104 in the housing 40 of the bridge-gearbox assembly. The oil accumulation section 104 is formed, for example, by an oil bath or an oil pan formed in the lower part of the housing 40 of the bridge-gearbox assembly. For example, after cooling the respective motors 2, 3, the oil is returned to the oil storage section 104 provided at the bottom of the housing 40 of the axle-gearbox assembly, for example, by gravity. As described above, when the oil circulates in the cooling circuit 210, the oil accumulated in the oil storage section 104 is pumped to the inverter 21 and the respective motors 2, 3 in the cooling circuit 210, by means of the electric oil pump 102, cools the respective motors 2, 3 and then returns to oil storage section 104.

[0052] 2-2. Grease circuit

Lubrication circuit 220 includes a mechanical oil pump 101, which is a second oil pump, a lubrication requiring part 30, which is a lubrication target, and an oil accumulation section 104. Lubrication circuit 220 delivers oil discharged from mechanical oil pump 101 to a lubrication requiring part 30 without air-cooling the oil using an HV radiator 103.

[0053] The mechanical oil pump 101 is configured to be driven by the engine 1 (illustrated in FIG. 1), draws in the oil accumulated in the oil storage section 104, and discharges the oil from the outlet port. The mechanical oil pump 101 discharges oil, which is to be supplied to the lubricating part 30 (gear) as a lubricating oil. The third oil supply channel 204 is connected to the outlet port of the mechanical oil pump 101. The third oil supply channel 204 includes a second oil outlet channel connected to the exhaust port of the mechanical oil pump 101, and a lubricating oil channel on the discharge side of the second oil discharge channel, the lubricant the oil channel allows oil to be supplied to the lubricating part 30. Oil discharged from the mechanical oil pump 101 into the third oil supply channel 204 is pumped into the lubricant guide portion 30 by the discharge pressure of the mechanical oil pump 101 lubrication circuit 220. In addition, a mechanical oil pump 101 is provided in the housing 40 of the axle-gearbox assembly, and therefore, the entire path of the lubrication circuit 220 is formed in the housing 40 of the axle-gearbox assembly. For example, a third supply oil channel 204 (lubricating oil channel), which is an oil channel (oil channel for the shaft core), formed on the inside of the input shaft 6, illustrated in FIG. 1 includes an outlet formed on the input shaft 6. Oil pumped from the mechanical oil pump 101 into the lubricating part 30 in the lubrication circuit 220 is discharged from the third oil supply channel 204 (input shaft outlet 6) to the separation mechanism 5 power (requiring lubrication part 30). Oil discharged from the third oil supply passage 204 lubricates a plurality of gears in the housing 40 of the axle-gearbox assembly.

[0054] After lubricating the lubricating portion 30, oil flows into the oil storage section 104 in the housing 40 of the bridge-gearbox assembly. For example, after lubricating the lubricating part 30, the oil is returned to the oil storage section 104, for example, by gravity or rotational force (centrifugal force) of the gears. As described above, when the oil circulates in the lubrication circuit 220, the oil accumulated in the oil storage section 104 is pumped through the inside of the lubrication circuit 220 by the mechanical oil pump 101, lubricates the lubricating portion 30, and then returns to the oil storage section 104.

[0055] Here, the lubricating portion 30 includes other gears that need to be lubricated with oil that lubricates certain gears. For example, in the vehicle Ve illustrated in FIG. 1, a third oil supply channel 204 (mainly a lubricating oil channel) is formed on the inside of the input shaft 6, and oil that lubricates the power separation mechanism 5 (sun gear 5S, ring gear 5R and satellite gear) from the input shaft 6, moves, for example, by gravity or centrifugal force and lubricates other gears (output gear 7 and gear mechanism 8 of the reverse shaft). The differential gear 9 can be made so that part of the gears is immersed in oil in the oil accumulation section 104 and takes oil, and thereby the differential gear 9 is lubricated. In addition, depending on the design of the housing 40 of the axle-gearbox assembly before the oil that lubricates the power sharing mechanism 5 lubricates the differential gear 9, the oil may return to the oil storage section 104. Thus, the differential gear 9 may not be included in the lubricating part 30.

[0056] 3. Comparison with comparative example

Here, to describe the advantages of the cooling system 100, the cooling system 100 and a comparative example are compared. First, a cooling system according to a comparative example is described with reference to FIG. 10. Thereafter, a comparison between the cooling system 100 and a comparative example is described.

[0057] 3-1. Comparative example

FIG. 10 is a circuit diagram illustrating a schematic configuration of a cooling system 300 according to a comparative example. In the cooling system 300 according to a comparative example, the inverter cooling circuit 310 and the oil channel 320 of the bridge-gearbox assembly are formed by respective independent flow channels. An inverter cooling circuit 310 is formed by a water channel in which cooling water of a hybrid (LLC) circulates as a cooling medium. The oil channel 320 of the axle-gearbox assembly is formed by an oil channel in which transmission lubricating oil (T / M lubricating oil) circulates as a coolant.

[0058] More specifically, the inverter cooling circuit 310 includes an electric water pump 311 (EWP), an HV radiator 312 that performs heat exchange between the cooling water of the hybrid (hereinafter referred to as "cooling HV water") and air, the inverter 313, electrically connected to respective motors 2, 3, a heat exchanger 314 that performs heat exchange between the HV-cooling water and the oil in the oil channel 320 of the bridge-gearbox assembly, and an expansion tank 315 that collects the HV-cooling water. The inverter cooling circuit 310 is a circulating water channel for cooling the inverter 313 using HV cooling water.

[0059] In the inverter cooling circuit 310, the electric water pump 311 draws in the HV cooling water stored in the expansion tank 315 and discharges the HV cooling water from the outlet port. The HV-cooling water discharged from the electric water pump 311 is cooled by air through an HV-radiator 312 and then supplied to an inverter 313. The inverter 313 is cooled by an HV-cooling water cooled by air by an HV-radiator 312. After cooling of the inverter 313, the HV-cooling water flows into heat exchanger 314 and exchanges heat with oil and then is pumped into expansion tank 315.

[0060] The oil channel 320 of the bridge-gear assembly includes a mechanical oil pump 321, a heat exchanger 314, a first motor 2, a second motor 3, a lubricating portion 30, and an oil storage section 322. The oil channel 320 of the bridge-gearbox assembly includes an oil channel (a cooling oil channel) that provides heat exchange between the oil discharged from the mechanical oil pump 321 and the cooling HV water via a heat exchanger 314, and then the oil to be supplied to the respective motors 2, 3. In addition, the oil channel 320 of the axle-gearbox assembly includes an oil channel (lubricating oil channel), which enables the supply of oil discharged from the mechanical oil pump 321 to the lubricating portion 30 without performing heat exchange with cooling HV water by means of heat exchanger 314. Here, in contrast to the oil storage section 104 of the first embodiment described above, the oil accumulated in the oil storage section 322 is oil that should not be supplied to HV radiator 312 and inverter 313.

[0061] 3-2. Comparison

The cooling system 100 according to the first embodiment is advantageous in comparison with the cooling system 300 according to the comparative example, firstly, in terms of cooling performance and, secondly, in design.

[0062] 3-2-1. Cooling performance

Below, emphasis is placed on the cooling performance of the inverter. An aspect common to the first embodiment and comparative example is that in the inverter 21 or 313, the inverter element, powered by electricity, is a heat-generating part (heat source).

[0063] In the inverter cooling circuit 310 according to a comparative example, the HV-cooling water, which is a cooling medium, has electrical conductivity, and therefore, due to safety, the HV-cooling water cannot be brought into contact with the inverter element (the heat-generating part of the inverter) powered by electricity. In the heat exchange between the heat-generating part of the inverter and the cooling HV water, it is necessary to provide an insulating plate (intermediate element), for example, a heat sink between the heat-generating part of the inverter and the cooling HV water. Thus, the cooling of the heat-generating part of the inverter by means of the cooling HV water is indirect cooling through the insulating plate, and therefore, the thermal resistance of the part between the cooling HV-water and the heat-generating part of the inverter increases by a value in the insulating plate. For example, if a heat transfer element is provided in a heat transfer path from an inverter element to an insulating plate (heat sink), the thermal resistance increases by a value in the heat transfer element. In addition, the ability to generate heat of the inverter element can be reduced not only by means of heat transfer rates between the elements included in the heat transfer path, but also by the specific heat conductivity of the elements themselves.

[0064] In the cooling system 100 according to the first embodiment, the oil, which is a cooling substance, has an insulating property, and therefore, when the oil cools the inverter 21, the oil can be brought into contact with the inverter element (the heat-generating part of the inverter) supplied with using electricity. In the cooling system 100, direct heat transfer can be performed between the heat-generating part of the inverter and the oil (coolant). In other words, the cooling system 100 allows direct cooling of the inverter element by means of a cooling agent having an insulating property. Therefore, in contrast to the comparative example, the cooling system 100 does not require an insulating plate such as a heat sink, providing a reduction in thermal resistance between the cooling substance (oil) and the heat-generating part of the inverter as compared with the comparative example. Therefore, the first embodiment provides an improvement in the cooling ability of the inverter element as compared with the comparative example and thereby improving the cooling performance of the inverter 21. In addition, improving the cooling ability of the inverter element leads to an improvement in the heat resistance of the inverter 21. Here, The inverter is a box covered with a casing.

[0065] Furthermore, the cooling system 300 according to the comparative example is configured such that the oil is pumped both into the motors 2, 3 (the cooling part) and the lubricating part 30 by means of one mechanical oil pump 321. Thus, it is difficult to control the volume of oil supplied to the part requiring cooling and the volume of oil supplied to the part requiring lubrication 30. For example, in the case of a vehicle requiring oil heating requiring lubrication of part 30 (heating is prioritized), for example, at a launch vehicle Ve, in spite of the actuation of the mechanical oil pump 321 so as to supply oil to the lubrication requiring portion 30, part of the oil supplied to requiring cooling part (motors 2, 3). This can lead to a decrease in the volume of oil supplied for heating. In this case, the oil is supplied to the part requiring cooling, which to a lesser extent requires cooling. This can lead to an increase in losses caused by the shaking of the oil by means of the rotating rotors of the respective motors 2, 3 (loss of resistance by shaking), and by losses due to sliding with significant friction of the rotors by oil (loss of resistance by sliding). Alternatively, if the vehicle requires cooling at least one of the first motor 2 and the second motor 3 (cooling is prioritized), despite the actuation of the mechanical oil pump 321 in such a way as to supply oil to the cooling part (motors 2, 3 ) as a coolant, part of the oil is supplied to the part 30 requiring lubrication. This leads to a decrease in the volume of oil supplied as a coolant, which may reduce the cooling ability of motors 2, 3. In addition, a volume of oil can be supplied to the lubricating part 30, leading to an increase in resistance loss during agitation and slip resistance caused in the lubricating part 30. As described above, an increase in resistance loss during agitation and loss on sliding resistance in the components of the electric motor (in the respective motors 2, 3) and the lubricated components (in the lubricating part 30) due to oil can cause a decrease in fuel efficiency.

[0066] Furthermore, in the cooling system 300 according to the comparative example, the oil in the oil channel 320 of the bridge-gear assembly generates heat to the HV-cooling water in the inverter cooling circuit 310 through the heat exchanger 314. In other words, the HV-cooling water is cooled air through an HV radiator 312, i.e. heat of oil is generated in the HV radiator 312 through the cooling HV water. Therefore, the heat dissipation efficiency of the oil is not good. This may reduce the cooling effect of the respective motors 2, 3 by means of oil.

[0067] In the first embodiment, the oil circulation circuit 200, including the cooling circuit 210 and the lubrication circuit 220, allows the supply of oil, having different temperatures, to components requiring cooling (inverter 21 and motors 2, 3), and components requiring heating (requiring lubrication part 30), respectively. In addition, the electric oil pump 102, which is the first oil pump provided in the cooling circuit 210, and the mechanical oil pump 101, which is the second oil pump provided in the lubrication circuit 220, can be separately driven. For example, in cases where the Ve vehicle requires cooling of engines 2, 3, for example, in cases where the Ve vehicle is traveling at high speed or is traveling on an elevated road (cooling is prioritized), the electric oil pump 102 may be driven action under the control of control module 150. Therefore, the cooling system 100 can provide both cooling performance and lubricant performance.

[0068] Furthermore, in the cooling system 100 according to the first embodiment, the electric oil pump 102 is designed to supply oil to the inverter 21 and motors 2, 3 in the cooling circuit 210, and can be controlled by the control unit 150. Thus, the electric oil pump 102 provides control of the oil temperature taking into account the temperature of the inverter and the temperature of the motor. On the other hand, in a comparative example, an electric water pump 311 for the inverter cooling circuit 310 and a mechanical oil pump 321 for the oil channel 320 of the bridge-gear assembly are provided, and therefore, the inverter temperature and the temperature of the motor are separately controlled. Therefore, according to the first embodiment, the control may be simpler in order to provide optimum oil temperatures according to the driving state of the vehicle Ve, in comparison with the comparative example.

[0069] 3-2-2. Design

Furthermore, with respect to design, the first embodiment provides a reduction in the number of components compared to the comparative example. For example, the heat exchanger 314, the expansion tank 315, and part of the pipes included in the water channel in the comparative example may be omitted. In addition, in the first embodiment, HV-cooling water is not required, which is a component specially designed for the inverter cooling circuit 310 in the comparative example, and thereby eliminating one refrigerant. In short, the cooling system 100 according to the first embodiment requires only one cooling agent (oil only), and this eliminates the need to provide overlapping components, providing a compact and lightweight system configuration. In addition, the exclusion of components (including HV-cooling water) provides cost savings. In addition, the large-sized cooling system 300 has poor installation capability in a vehicle, resulting in poor assembly capabilities.

[0070] 3-2-3. Fluidity of oil

The fluidity of the oil is described below with reference to FIG. 3 and 4. FIG. 3 is a diagram for describing a comparison between the kinetic viscosity of the oil used in the cooling system 100 according to the first embodiment and the kinetic viscosity of a conventional oil. FIG. 4 is a diagram for describing a relationship between a pump inlet value and an oil temperature. In this description, the oil used in the cooling system 100 is called the “proposed oil”, and the oil used in the conventional cooling system is called the “ordinary oil”. In addition, the solid line indicated in FIG. 3 represents the kinetic viscosity of the proposed oil, and the dotted line represents the kinetic viscosity of a conventional oil. The solid line shown in FIG. 4 represents the amount of release (flow rate) with the proposed oil, and the dashed line represents the amount of release (flow rate) with the conventional oil.

[0071] As illustrated in FIG. 3, the kinetic viscosity of the proposed oil is low compared to the kinetic viscosity of a conventional oil at any oil temperature and, in particular, is significantly reduced in the low temperature range. More specifically, in the temperature range of the oil, in which the oil temperature is negative, the viscosity of the proposed oil is significantly reduced compared to conventional oil. In the temperature range of the oil, in which the oil temperature is positive, the proposed oil shows a large decrease in viscosity. For example, in the oil temperature range of approximately 10-30 ° C, the proposed oil exhibits a 60% reduction in kinetic viscosity relative to conventional oils.

[0072] Thus, the use of the proposed oil, which is a low viscosity oil, in the cooling system 100 reduces the pressure loss caused when the proposed oil flows in the oil circulation circuit 200. Therefore, the proposed oil can forcibly flow inside the inverter 21 as a coolant while suppressing the increase in pressure loss. In addition, the sliding resistance caused by the oil decreases in the rotary elements, such as the rotors of the respective motors 2, 3, and in the lubricating part 30, which are in contact with the oil. Therefore, the temperature range of the oil in which the electric oil pump 102 operates can be expanded to an extremely low temperature range. In other words, the maximum operating temperature of the oil of the electric oil pump 102 is reduced to an extremely low temperature. The maximum operating temperature of the oil is the temperature of the oil at which the amount of discharge from the electric oil pump 102 (flow rate per unit time) reaches the desired output. FIG. 4 indicates the difference between the proposed oil and conventional oil in terms of the limiting operating temperature of the oil for the electric oil pump 102.

[0073] As illustrated in FIG. 4, the maximum operating temperature Tlim of the oil for the electric oil pump 102 that produces the oil of the invention is an extremely low temperature of minus several tens of degrees Celsius. The operating temperature limit Tlim of the oil for electric oil pump 102 may be from about -40 ° C to -20 ° C. On the other hand, the maximum operating temperature of the oil of the electric oil pump 102, which releases conventional oil, is approximately zero degrees Celsius. As described above, the temperature range of the oil in which the electric oil pump 102 operates extends to a range of extremely low temperatures, including minus several tens of degrees Celsius. Thus, the fluidity of the proposed oil is ensured even if the ambient temperature is an extremely low temperature of about minus 30 ° C. In addition, the amount of release when using the proposed oil is large compared to the amount of release when using conventional oil, at any oil temperature, and in particular, shows a significant increase in the low temperature range.

[0074] As described above, the cooling system 100 according to the first embodiment includes an oil circulation circuit 200, in which only oil circulates through the inverter oil channel and the oil channel of the bridge-gearbox assembly. Therefore, the size of the cooling system 100 may be reduced. In the oil circulation circuit 200, oil cooled by air by means of the HV radiator 103 can be supplied to the inverter 21 and motors 2, 3 (cooling part) by the cooling circuit 210, and oil not cooled by air by the HV radiator 103 can be supplied into the lubricating portion 30 through a lubrication circuit 220. Therefore, the cooling system 100 can provide both cooling performance and lubricant performance. In addition, the oil can be cooled (air-cooled) by means of an HV radiator 103, and therefore, the cooling ability of the oil is improved. In addition, air-cooled oil is supplied to the respective motors 2, 3, and because of this, the ability to cool motors 2, 3 is improved. In addition, in the cooling circuit 210, the inverter 21 and any of the motors 2, 3 are arranged in series. Therefore, a reduction in the volume of oil supplied to the motors 2, 3 can be suppressed.

[0075] In addition, improving the cooling ability of the oil provides a reduction in losses (loss in the winding and core loss) in the respective motors 2, 3, which leads to improved fuel efficiency and heat resistance of the respective motors 2, 3. In addition, the cooling ability the inverter 21 is also improved and therefore reduces the losses (for example, losses in the winding) in the inverter 21, which leads to increased fuel efficiency and heat resistance of the inverter 21.

[0076] 4. Modification

FIG. 5 is a circuit diagram illustrating a schematic configuration of a cooling system 100 according to a modification. In the description of the modification, components similar to the components of the above-described first embodiment contain reference numbers that are identical to the reference numbers of the above-described first embodiment, and their description is omitted.

[0077] As illustrated in FIG. 5, in the cooling system 100 according to a modification, the inverter 21 and the respective motors 2, 3 are connected in parallel on the discharge side of the electric oil pump 102 in the cooling circuit 210 of the oil circulation circuit 200. More specifically, the inverter 21, the first motor 2 and the second motor 3 are arranged in parallel in the cooling circuit 210.

[0078] More specifically, the post-cooling oil channel 205 is connected to the output of the HV radiator 103. The oil channel on the downstream side of the post-cooling oil channel 205 branches at a branch point P. At the branch point P, the post-cooling oil channel 205, the first oil supply channel 202 and the second oil supply channel 203 (cooling pipe 203a MG1 and cooling pipe 203b MG2) communicate with each other. In other words, the oil channel in the interior of the inverter casing 21 communicates with the HV radiator 103 through the first oil supply channel 202 and the post-cooling oil channel 205. The cooling pipe 203a MG1 of the first motor 2 communicates with the HV radiator 103 through the post-cooling oil channel 205. The cooling pipe 203b MG2 of the second motor 3 communicates with the HV radiator 103 through a post-cooling oil channel 205. In other words, the cooling circuit 210 according to a modification is such that the oil to be supplied to the motors 2, 3 temporarily flows out of the limit The housing 40 of the bridge-gearbox assembly so as to pass through the HV radiator 103 without passing through the inverter 21.

[0079] The cooling system 100 according to a modification may supply air-cooled oil via the HV radiator 103 to the respective motors 2, 3 without passing through the inverter 21. Therefore, an increase in the temperature of the oil supplied to the respective motors 2, 3 is not allowed by cooling inverter 21, providing the possibility of cooling the respective motors 2, 3 by means of low-temperature oil. Therefore, the cooling ability of the respective motors 2, 3 is improved.

[0080] Here, the case in which the inverter 21 and the respective motors 2, 3 are arranged in series as described in the above-described first embodiment is compared, and the case in which the inverter 21 and the corresponding motors 2, 3 are arranged in parallel, as indicated in the modification. If the inverter 21 and the respective motors 2, 3 are arranged sequentially in the cooling circuit 210, the volume of oil supplied to the respective motors 2, 3 is large and the oil temperature is high compared to the case in which the inverter 21 and the motors 2, 3 are placed parallel. If the inverter 21 and the respective motors 2, 3 are arranged in parallel in the cooling circuit 210, the amount of oil supplied to the respective motors 2, 3 is small, and the oil temperature is low compared to the case in which the inverter 21 and the corresponding motors 2, 3 are placed sequentially.

[0081] It should be noted that the vehicle cooling system according to the present invention is not limited to the first embodiment and the modification described above, and arbitrary changes are possible without departing from the purpose of the present invention.

[0082] For example, the design and layout of the mechanical oil pump 101 is not specifically limited, provided that the design and layout are the design and layout that can be formed in the housing 40 of the axle-gearbox assembly. For example, it is possible that the mechanical oil pump 101 is not coaxial with the crankshaft of the engine 1. In this case, the mechanical oil pump 101 and the input shaft 6 are connected by a mechanism such as a gear transmission or chain mechanism in order to provide power transmission .

[0083] Furthermore, the types of two oil pumps included in the cooling system 100 are not limited to the types of the first embodiment described above. In other words, 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, the first oil pump and the second oil pump may be electric oil pumps. In this case, the second oil pump that pumps oil in the lubrication circuit 220 is an electric oil pump, and the second oil pump in the lubrication circuit 220 may be controlled by the control unit 150. Furthermore, according to the cooling system 100, a second oil pump formed from an electric oil pump can be driven when the vehicle Ve is stopped. In addition, a vehicle with a cooling system 100 installed therein is not limited to a hybrid vehicle and may be an electric vehicle (EV) using only motors as sources of driving power.

[0084] Furthermore, in the cooling system 100, the number of motors included in the cooling part is not limited, the number of motors, the number being a number other than two, may be targets for cooling. Although the first embodiment has been described in terms of the case in which the Ve vehicle is a two-engine hybrid vehicle, the vehicle may be a single-engine hybrid vehicle. Alternatively, the cooling system 100 may include three or more motors that are targets for cooling.

[0085] Furthermore, the cooling system 100 may have a water-cooled oil cooler in place of the HV radiator 103, which is an air-cooled oil cooler. The cooling system 100 may include only an oil cooler capable of cooling the oil, which is to be supplied to the inverter 21 and the respective motors 2, 3, which are targets for cooling. Thus, there are no restrictions on whether an air-cooled or water-cooled oil cooler is provided. For example, if the cooling system 100 has a water-cooled oil cooler, the water-cooled oil cooler may be a heat exchanger that exchanges heat between the oil flowing in the cooling circuit 210 and the engine cooling water.

[0086] Furthermore, the lubricating portion 30 may include a differential gear 9. In other words, there are no particular restrictions on whether or not the differential gear 9 is included in the lubricating portion 30.

[0087] Second Embodiment

The following describes a cooling system 100 according to a second embodiment with reference to FIG. 6-9. The cooling system 100 according to the second embodiment differs from the first embodiment by the inclusion of a three-phase heat exchanger, which causes heat exchange between the cooling water for the engine (hereinafter referred to as "cooling ENG water"), the oil for the engine (hereinafter referred to as "ENG oil") and lubricating T / M oil (hereinafter referred to as "T / M oil"). In the description of the second embodiment, a description of components that are similar to the components of the first embodiment is omitted, and reference numbers with numbers used in the first embodiment are used for such components.

[0088] 5. Cooling system

FIG. 6 is a circuit diagram illustrating a schematic configuration of a cooling system 100 according to a second embodiment. As illustrated in FIG. 6, the cooling system 100 according to the second embodiment includes a three-phase heat exchanger 105 (hereinafter referred to simply as the “heat exchanger”), which causes heat exchange between the cooling ENG water, the ENG oil and the T / M oil. In addition, the oil circulation circuit 200 is configured to allow T / M oil flowing inside the lubricant circuit 220 to flow into the heat exchanger 105, but not to allow the T / M oil flowing inside the circuit 210 to the heat exchanger 105. In addition, a lubrication circuit 220, an ENG cooling circuit 410, and an ENG oil circulation circuit 420 are connected to a heat exchanger 105.

[0089] 5-1. Grease circuit

Lubrication circuit 220 includes a mechanical oil pump 101, a heat exchanger 105, a lubricating portion 30, and an oil storage section 104. Lubrication circuit 220 delivers oil discharged from mechanical oil pump 101 to a lubrication portion 30 through a heat exchanger 105.

[0090] The second exhaust oil channel 206 is connected to the exhaust port of the mechanical oil pump 101. Oil discharged by the mechanical oil pump 101 into the second exhaust oil channel 206 is pumped into the heat exchanger 105 by the pressure at the outlet of the mechanical oil pump 101 in the lubrication circuit 220 and further into the lubricating part 30 through a heat exchanger 105.

[0091] The heat exchanger 105 is a heat exchanger configured to permit heat exchange between the respective three fluids, which are T / M oil, ENG-cooling water, and ENG-oil. In other words, the heat exchanger 105 is configured to permit heat transfer between the T / M oil and the cooling ENG water and to allow heat transfer between the T / M oil and the ENG oil. In addition, the heat exchanger 105 is configured to permit heat exchange between the cooling ENG water and the ENG oil. The second exhaust oil channel 206 is connected to the input of the heat exchanger 105 in the lubrication circuit 220. The fourth oil supply channel 207 is connected to the outlet of the heat exchanger 105 in the lubrication circuit 220. The fourth oil supply channel 207 is a lubricating oil channel that delivers oil to a lubricating portion 30 on the exhaust side of the heat exchanger 105.

[0092] In addition, a first oil temperature sensor 151 is provided in the lubrication circuit 220, which senses the temperature Ttm of the T / M oil. For example, the first oil temperature sensor 151, which is provided in the second oil outlet 206 in the lubrication circuit 220, detects the temperature Ttm of the T / M oil discharged from the mechanical oil pump 101. Then, the temperature Ttm of the T / M oil (hereinafter referred to as " temperature T / M oil "), detected by the first oil temperature sensor 151, is input to the control unit 150 as a determination signal (temperature information).

[0093] 5-2. ENG cooling circuit

The ENG cooling circuit 410 is a circuit in which ENG cooling water circulates. As illustrated in FIG. 6, the ENG cooling circuit 410 includes a heat exchanger 105 and a first switching valve 411 (on-off valve) that selectively shuts off the flow of ENG cooling water returning to the engine 1 through the heat exchanger 105. In addition, the ENG cooling circuit 410 includes known components, such as a water pump (not illustrated).

[0094] The first water channel 412, which supplies the cooling ENG water to the heat exchanger 105, is connected to the cooling water outlet of the engine 1 and to the cooling water inlet of the heat exchanger 105. In addition, the second water channel 413, which supplies the cooling ENG water, subjected to heat exchange by means of a heat exchanger 105, into the engine 1, is connected to the cooling water outlet of the heat exchanger 105 and to the cooling water inlet of the engine 1. In the example illustrated in FIG. 6, a first switching valve 411 is provided in a second water channel 413.

[0095] The first switching valve 411 switches between an open state (on) in which the flow of cooling ENG water returning to the engine 1 through the heat exchanger 105 is allowed, and a closed state (shutdown) in which the flow of cooling ENG water returning to engine 1 through heat exchanger 105 is not permitted. The first switching valve 411 is formed, for example, from an electromagnetic valve, and the opening and closing of the first switching valve 411 are controlled by a control unit 150. If the first switching valve 411 is in the open state, the cooling ENG water flows in the first water channel 412 from the engine 1 to the heat exchanger 105, and the cooling ENG water flows in the second water channel 413 from the heat exchanger 105 to the engine 1. On the other hand, if the first switching valve 411 is closed in the ENG cooling circuit 410, there is no flow of cooling ENG water returning to the engine 1 through the heat exchanger 105.

[0096] In addition, a water temperature sensor 152 is provided in the ENG cooling circuit 410, which senses a temperature Thw (hereinafter referred to as the "ENG cooling water temperature") of the ENG cooling water. A water temperature sensor 152 is mounted on the inlet side of the heat exchanger 105 in the ENG oil circulation loop 420. In addition, information regarding the temperature Thw of cooling ENG water detected by the water temperature sensor 152 is input to the control unit 150 as a determination signal.

[0097] 5-3. ENG oil circuit

The ENG oil circulation circuit 420 is a circuit in which the ENG oil circulates. As illustrated in FIG. 6, the ENG oil circulation loop 420 includes a heat exchanger 105 and a second switching valve 421 (on-off valve), which selectively shuts off the flow of ENG oil returning to the engine 1 through the heat exchanger 105.

[0098] The first oil channel 422, which supplies the ENG oil to the heat exchanger 105, is connected to the outlet for the ENG oil of the engine 1 and to the input for the ENG oil of the heat exchanger 105. In addition, the second oil channel 423 that supplies the ENG oil subjected to heat exchange in the heat exchanger 105, into the engine 1, is connected to the outlet for the ENG oil of the heat exchanger 105 and to the input for the ENG oil of the engine 1. In the example illustrated in FIG. 6, a second switching valve 421 is provided in the second oil channel 423.

[0099] The second switching valve 421 switches between an open state (on) in which the flow of ENG oil returning to the engine 1 through the heat exchanger 105 is enabled and a closed state (shutdown) in which the flow of ENG oil returning to the engine 1 through heat exchanger 105 is not permitted. The second switching valve 421 is formed, for example, from a solenoid valve, and the opening-closing of the second switching valve 421 are controlled by a control unit 150. If the second switching valve 421 is in the open state, ENG oil flows in the first oil channel 422 from the engine 1 to the heat exchanger 105, and the ENG oil flows inside the second oil channel 423 from the heat exchanger 105 to the engine 1. On the other hand, if the second switching the valve 421 is in the closed state in the circuit ENG-oil circulation 420, there is no flow of ENG-oil returning to the engine 1 through the heat exchanger 105.

[0100] In addition, a second oil temperature sensor 153 is provided in the ENG oil circulation loop 420, which senses the Toil temperature (hereinafter referred to as the "ENG oil temperature") of the ENG oil. A second oil temperature sensor 153 is mounted on the inlet side relative to the heat exchanger 105 in the ENG oil circulation circuit 420. Information regarding the Toil temperature of the ENG oil detected by the second oil temperature sensor 153 is input to the control unit 150 as a determination signal.

[0101] 6. The control module

The control unit 150 controls the opening-closing of the first switching valve 411 and the second switching valve 421 based on the detection signals (temperature Ttm of T / M oil, temperature Thw of cooling ENG water and temperature Toil of ENG oil) inputted from respective sensors 151- 153. In other words, the control unit 150 performs switching control to switch each of the first switching valve 411 and the second switching valve 421 between the open state and the closed state, and thereby controls the heat transfer state in the heat exchanger 105. More specifically, the control module 150 performs a comparison between temperature Ttm T / M oil, predefined temperature Ttm _{_1 of} oil for temperature Ttm T / M oil, temperature Thw of cooling ENG water, predefined temperature Thw _{_1} of odes for the temperature Thw of the ENG cooling water and the temperature of the Toil ENG oil to perform switching control.

[0102] The predetermined oil temperature Ttm _{_1} is a value set taking into account losses in the T / M block. The T / M block includes drive devices housed in the housing 40 of the bridge-gearbox assembly (first motor 2, second motor 3 and power transmission mechanism), and electrical components (eg, inverter 21) connected to the motors 2 , 3. Thus, losses in the TM block include losses caused in the power transmission mechanism (for example, losses caused by loss of slip resistance due to oil in the lubricating part 30) in addition to core losses and winding losses caused when motors 2, 3 are driven action. In addition, the losses in the T / M block have the characteristic of the variation in the losses in the T / M block as the temperature Ttm of the T / M oil (temperature characteristic) varies.

[0103] FIG. 7 is a diagram for describing the relationship between the losses in the T / M block and the temperature Ttm of the T / M oil. As illustrated in FIG. 7, if the temperature Ttm of the T / M oil falls within the oil temperature range that is lower than the predetermined temperature Ttm_{_one} oil losses in the T / M block are continuously reduced as the temperature Ttm of the T / M oil increases over time. On the other hand, if the temperature Ttm of the T / M oil falls within the oil temperature range that is higher than the predetermined temperature Ttm_{_one} oil losses in the T / M block continuously increase as the oil temperature increases over time. Thus, the loss in the T / M block due to the temperature Ttm of the T / M oil is the minimum value at a predetermined temperature Ttm_{_one} oils. This is because the losses in the T / M block can be divided into friction losses and losses in the motor, and friction losses decrease with increasing oil temperature, and losses in the motor increase with increasing oil temperature. Therefore, the control unit 150 performs switching control for each of the switching valves 411, 421 (control for heat transfer in the heat exchanger 105) using a predetermined temperature Ttm_{_one} oils for the temperature Ttm T / M oil as a threshold value.

[0104] FIG. 8 is a diagram illustrating changes in liquid temperature in a normal state of motion. Normal driving state means a state in which the vehicle is driven by propulsion power of engine 1. As illustrated in FIG. 8, if the vehicle Ve is in a normal driving state, the temperature of the liquids has the relationship “Ttm T / M oil temperature <ENG oil temperature Toil <ENG cooling water temperature Thw”. In addition, as the temperature Thw of the cooling ENG water is increased so that it is equal to or higher than the predetermined water temperature Thw _{_1} , complete control of the fuel consumption for the engine 1 (hereinafter referred to as "ENG fuel consumption control") is performed. In other words, the predetermined water temperature Thw _{_1} is a threshold value. ENG Fuel Consumption Management is a control performed to improve fuel efficiency. ENG fuel consumption control includes, for example, control in order to automatically stop engine 1 when the vehicle makes a brief stop, control in order to set operating points of engine 1 (engine speed and engine torque) on the optimal line fuel consumption at which the best efficiency is achieved, and EV-movement control in order to allow EV-movement, in which the vehicle moves due to the driving power, motors 2, 3. In addition to Although not illustrated in FIG. 8, in a high-load driving state, the temperature of the Toil ENG oil is higher than the temperature Ttm T / M oil and the temperature Thw of the ENG cooling water. For example, after continuing the normal state of motion indicated in FIG. 8, for a long time (for example, several hours), the vehicle enters a high-load driving state. Here, examples of the normal state of movement include HV-movement, in which the vehicle moves due to the driving power, engine 1 and corresponding motors 2, 3, and movement due to the engine, in which the vehicle moves due to the driving power, only the engine one.

[0105] 7. Heat management

FIG. 9 is a flowchart illustrating an example of heat transfer control. The control procedure indicated in FIG. 9 is performed by the control unit 150.

[0106] As illustrated in FIG. 9, the control unit 150 determines whether or not the temperature Ttm T / M oil is lower than the predetermined oil temperature Ttm _{_1} (step S1). The predefined oil temperature Ttm _{_1} is a threshold value set in advance.

[0107] If a positive determination that the temperature Ttm of the T / M oil is lower than the predetermined oil temperature Ttm _{_1} is performed in step S1 (step S1: “Yes”), the control unit 150 performs heating control so as to control by heat exchange in the heat exchanger 105 so as to heat the T / M oil (step S2). In this case, the control unit 150 determines whether or not the temperature THw of the cooling ENG water of the predetermined water temperature Thw _{_1} is higher (step S3). A predetermined water temperature Thw _{_1} is a threshold value set in advance.

[0108] If a positive determination is made in step S3 due to the temperature ENG cooling water Thw exceeding the predetermined water temperature Thw _{_1} (step S3: "Yes"), the control unit 150 controls the first switching valve 411 so that it turns on, and the second switching valve 421 so that it turns on (step S4). In step S4, the first changeover valve 411 and the second changeover valve 421 are opened, heat exchange is performed between the T / M oil and the ENG cooling water, and heat exchange is performed between the T / M oil and the ENG oil. After performing step S4, the control unit 150 completes the control procedure.

[0109] As described above, if a positive determination is made in step S3, as illustrated in FIG. 8 above, the temperature Thw of the ENG cooling water and the temperature of the Toil ENG oil are in a state in which the temperature Thw of the ENG ENG water and the temperature of the Toil ENG oil are higher than the Ttm T / M oil temperature. Then, in step S4, the heat of the cooling ENG water and ENG oil is transferred to the T / M oil, and the T / M oil is thereby heated. Therefore, T / M oil can be heated quickly by the heat of cooling ENG water and the heat of ENG oil. Therefore, the lubricating portion 30 can be quickly heated by T / M oil that passes through the heat exchanger 105.

[0110] If a negative determination is made in step S3 due to the temperature ENG cooling water Thw equal to or lower than the predetermined water temperature Thw _{_1} (step S3: "No"), the control unit 150 determines whether the temperature Ttm T / M is lower or not. - Toil ENG oil temperature oils (step S5).

[0111] If a positive determination is made in step S5 due to the temperature, Ttm of the T / M oil is lower than the Toil temperature of the ENG oil (step S5: "Yes"), the control unit 150 controls the first switching valve 411 so that it turns off, and the second switching valve 421 so that it turns on (step S6). In step S6, the second switching valve 421 is opened, the heat exchange is therefore performed between the T / M oil and the ENG oil, but the first switching valve 411 is closed, the heat exchange is therefore not performed between the T / M oil and the cooling ENG water. After performing step S6, the control unit 150 completes the control procedure.

[0112] As described above, if step S6 is performed after determining in step S5, the temperature Ttm of the T / M oil is in a state in which the temperature Ttm of the T / M oil is lower than the temperature of the Toil of the ENG oil, the heat of the ENG oil is transferred to The T / M oil in the heat exchanger 105, and the T / M oil is thereby heated. Therefore, the T / M oil can be quickly heated by the heat of the ENG oil. Therefore, the lubricating portion 30 can be quickly heated by the T / M oil that passes through the heat exchanger 105. In addition, if step S6 is performed after determining in step S5, the ENG cooling water does not provide heat to the T / M oil, and in view of this, the ENG cooling water is preferably heated until the cooling temperature THw of the ENG ENG water rises to a predetermined water temperature Thw _{_1} . Therefore, engine 1 is heated by cooling ENG water.

[0113] If a negative determination is made in step S5 due to the T / M oil temperature Ttm equal to or higher than the Toil ENG oil temperature (step S5: "No"), the control unit 150 controls the first switching valve 411 and the second switching valve 421 such the way that they turn off (step S7). In step S7, the first switching valve 411 and the second switching valve 421 are closed; therefore, heat exchange is not performed between the T / M oil and the cooling ENG water, and also between the T / M oil and the ENG oil. In other words, T / M oil does not accept heat from ENG cooling water and ENG oil. After performing step S7, the control unit 150 completes the control procedure.

[0114] As described above, if step S7 is performed after determining in step S5, the temperature Ttm of the T / M oil is in a state in which the temperature Ttm of the T / M oil is higher than the temperature Toil of the ENG oil, and therefore, heat transfer T / M-oils in ENG-oil may not be allowed by closing the second switching valve 421. Therefore, when the T / M-oil is heated, it is possible to prevent the heat from being removed by the T / M-oil by ENG-oil. Thus, the lubricating portion 30 can be quickly heated by T / M oil, which passes through the heat exchanger 105.

[0115] On the other hand, if a negative determination is made in step S1 due to the T / M oil temperature Ttm equal to or higher than the predetermined oil temperature Ttm _{_1} (step S1: “No”), the control unit 150 performs cooling control so that to control the state of heat transfer in the heat exchanger 105 so as to cool the T / M oil (step S8). In this case, the control unit 150 determines whether or not the Toil temperature of the ENG oil is lower than the temperature Thw of the cooling ENG water (step S9).

[0116] A positive determination is made in step S9 due to the temperature of the Toil ENG oil below the temperature Thw of the cooling ENG water (step S9: "Yes"), the control unit 150 determines whether the Toil ENG temperature Ttm T / M oil is lower or not oil (step S10).

[0117] If a positive determination is made in step S10 due to the temperature Ttm of the T / M oil below the Toil temperature of the ENG oil (step S10: "Yes"), the control unit 150 performs step S7 described above to control the first switching valve 411 and the second switching valve 421 so that they shut off.

[0118] As described above, if step S7 is performed after determining in step S10, the temperature Ttm of the T / M oil is in a state in which the temperature Ttm of the T / M oil is lower than the temperature Thw of the cooling ENG water and the temperature of Toil ENG oil both the heat transfer of cooling ENG water to T / M oil and heat transfer of ENG oil to T / M oil can therefore be prevented by closing the first switching valve 411 and the second switching valve 421. Therefore, when T / M-oil is cooled, heating of T / M-oil can be prevented by means of cooling ENG-water and EN G-oils, providing cooling capacity of T / M-oils.

[0119] If a negative determination is made in step S10 due to the T / T oil temperature Ttm equal to or higher than the ENG oil oil temperature Toil (step S10: "No"), the control unit 150 performs step S6 described above to control the first switching the valve 411 so that it turns off, and the second switching valve 421 so that it turns on.

[0120] As described above, if step S6 is performed after determining in step S10, the temperature Ttm of the T / M oil is in a state in which the temperature Ttm of the T / M oil is higher than the temperature of the Toil ENG oil, and therefore, heat transfer to the cooling medium ENG water in the T / M oil may not be allowed by closing the first switching valve 411, and the heat of the T / M oil can be transferred to the ENG oil by opening the second switching valve 421. Therefore, when the T / M oil is cooled, it is possible prevent heating of T / M oil with ENG cooling water, and T / M oil can T ENG-cooled by oil, ensuring cooling ability T / M-oil.

[0121] If the negative determination is made in step S9 due to the Toil temperature of the ENG oil equal to or higher than the temperature Thw of the ENG cooling water (step S9: "No"), the control unit 150 determines whether the temperature Ttm T / M- is lower or not. oil temperature Thw ENG-cooling water (step S11).

[0122] If a positive determination is made in step S11 due to the temperature Ttm of the T / M oil below the temperature Thw of the cooling ENG water (step S11: "Yes"), the control unit 150 performs step S7 described above to control the first switching valve 411 and a second switching valve 421 so that they are turned off.

[0123] As described above, if step S7 is performed after determining in step S11, the relationship “T / M oil temperature Ttm <ENG ENG water water temperature Thw ENG oil temperature Toil” is set between the temperatures of the respective liquids. Thus, both heat transfer of cooling ENG water to T / M oil and heat transfer of ENG oil to T / M oil can be prevented by closing the first switching valve 411 and the second switching valve 421. Therefore, when T / M-oil is cooled, it is possible to prevent heating of T / M-oil by means of cooling ENG-water and ENG-oil, providing cooling ability of T / M-oil.

[0124] If a negative determination is made in step S11 due to the T / M oil temperature Ttm equal to or higher than the cooling water ENG temperature Thw (step S11: "No"), the control unit 150 controls the first switching valve 411 so that it is turned on, and by the second switching valve 421 so that it is turned off (step S12). In step S12, the first switching valve 411 opens, heat exchange is therefore performed between the T / M oil and the cooling ENG water, but the second switching valve 421 is closed, the heat exchange is therefore not performed between the T / M oil and the ENG oil. After performing step S12, the control unit 150 completes the control procedure.

[0125] As described above, if the negative determination is performed in step S11, the temperature Ttm of the T / M oil is in a state in which the temperature Ttm of the T / M oil is higher than the temperature Thw of the cooling ENG water, and therefore, the heat T / M the oil can be transferred to the ENG cooling water by opening the first switching valve 411, and heat transfer of the ENG oil to the T / M oil may not be allowed by closing the second switching valve 421. Therefore, when the T / M oil is cooled, T / M-oil can be cooled by heat in the cooling medium. ENG-water, and can prevent heating of T / M-ENG-oil through oil cooling capacity providing T / M-oil.

[0126] 8. Comparison with comparative example

Here, to describe the advantages of the cooling system 100 according to the second embodiment, the cooling system 100 and a comparative example are compared with reference to FIG. 11. Here, for the cooling system 500, which is illustrated in FIG. 11, a description of components that are similar to those of the cooling system 300 illustrated in FIG. 10 described above is omitted and reference numerals used for the cooling system 300 are used.

[0127] FIG. 11 is a circuit diagram illustrating a schematic configuration of a cooling system 500 according to a comparative example. As illustrated in FIG. 11, the cooling system 500 according to the comparative example does not include the heat exchanger 105 described above. In other words, in the cooling system 500, heat is not exchanged between the T / M oil and the liquid on the engine side 1 (ENG cooling water in the ENG cooling circuit 410 or ENG oil in the circuit 420 ENG-oil circulation). Therefore, in the cooling system 500, when the lubricating part 30 is heated, the T / M oil cannot be heated by the liquid on the engine 1 side (ENG cooling water or ENG oil), resulting in a delay with increasing temperature of the T / M oil . Thus, in the normal state of movement, the loss of resistance during agitation and the loss of resistance during sliding caused by the lubricating part 30 can become large. In addition, in a state of movement with a high load, the cooling ability of T / M oil is reduced, which can lead to an increase in losses (losses in the winding and losses in the core) in the motor components.

[0128] The advantages of the second embodiment include heating performance and fuel efficiency in addition to the advantages similar to the advantages of the first embodiment described above (cooling performance and design). According to the second embodiment, during heating, heat exchange is performed between the liquid on the engine side 1 (cooling ENG water or ENG oil) and the T / M oil, and thereby the temperature Ttm of the T / M oil is accelerated, providing fast completion of heating. Consequently, the loss of resistance during agitation and the loss of resistance to slip (T / M friction) in the lubricating part 30 can be reduced, thereby increasing fuel efficiency.

[0129] Furthermore, by performing the shift control taking into account the temperature Thw of the ENG cooling water, friction in the engine 1 (hereinafter referred to as "ENG friction") and the negative effect with respect to controlling the ENG fuel consumption can be minimized. In addition, when the temperature sensitivity of ENG friction oil for ENG oil is compared with the temperature sensitivity of T / M friction oil for T / M oil, the temperature sensitivity of T / M friction oil exceeds the temperature sensitivity of ENG friction oil. Thus, if the temperature of the Toil ENG oil is in a state in which the temperature of the Toil ENG oil is higher than the temperature Ttm of the T / M oil, heat transfer of the ENG oil to the T / M oil reduces T / M friction, providing an increase in efficiency fuel use. Here, ENG friction decreases as the temperature of the Toil ENG oil rises.

[0130] As described above, reducing the pressure loss caused by the T / M oil and expanding the range of the maximum operating temperature of the oil for the electric oil pump 102 provides a sufficient flow rate (provides the required flow rate) of the T / M oil and increases the degree of freedom in an electric oil pump. Therefore, an oil circulation circuit 200 may be provided having a circuit configuration in which an inverter circuit and an oil channel of a bridge-gearbox assembly are integrated.

[0131] As described above, according to the second embodiment, in addition to the advantages provided by the above-described first embodiment, the T / M oil can quickly heat up and the heating of the power transmission mechanism is completed quickly, and therefore, the T / M friction is reduced, providing increasing fuel efficiency.

[0132] It should be noted that the vehicle cooling system according to the present invention is not limited to the second embodiment described above, and arbitrary changes are possible without departing from the purpose of the present invention.

[0133] For example, each of the switching valves 411, 421 is not limited to a solenoid valve and may be formed from a two-position valve that can be controlled by a control unit 150.

[0134] Furthermore, the first oil temperature sensor 151 may be mounted on the inlet side with respect to the heat exchanger 105 in the lubrication circuit 220. For example, a first oil temperature sensor 151 may be provided in the oil storage section 104 and detecting the temperature Ttm of the T / M oil accumulated in the oil storage section 104. Similarly, the installation position of the water temperature sensor 152 is not specifically limited provided that the installation position is superior to the heat exchanger 105 in the ENG cooling circuit 410. The installation position of the second oil temperature sensor 153 is also not particularly limited, provided that the installation position is superior to the heat exchanger 105 in the ENG oil circulation circuit 420.

Claims (27)

1. The vehicle cooling system installed in the vehicle, which includes an electric motor, an inverter electrically connected to the electric motor, and a power transmission mechanism that transmits the driving power output from the electric motor to the wheel, the vehicle cooling system comprising: - oil circulation circuit, including: - oil accumulation section; a first circuit including a first oil pump that draws in oil accumulated in the oil storage section, and discharges oil as a coolant to be supplied to the inverter and electric motor, and an oil cooler provided between the first oil pump and the inverter or electric motor wherein the oil cooler cools the oil to be supplied to the inverter and electric motor; and - a second circuit, including a second oil pump, which sucks in the oil accumulated in the oil storage section and discharges oil, which must be supplied to the lubricating part included in the power transmission mechanism without passing through the oil cooler. 2. The vehicle cooling system according to claim 1, in which in the first circuit the inverter and electric motor are provided on the exhaust side of the first oil pump, the inverter and the electric motor are connected in series and the electric motor is provided on the exhaust side of the inverter. 3. The vehicle cooling system according to claim 1, in which in the first circuit an inverter and an electric motor are provided on the downstream side of the first oil pump and the inverter and the electric motor are connected in parallel. 4. The vehicle cooling system according to claim 1, wherein the electric motor includes a stator and a rotor, and in the first circuit, a cooling pipe of an electric motor for supplying oil to the electric motor includes an outlet for discharging oil into the stator. 5. The vehicle cooling system of claim 1, wherein the oil flowing in the first circuit has an insulating property. 6. The vehicle cooling system according to claim 1, wherein the inverter is configured such that oil discharged from the first oil pump flows inside as a coolant. 7. The vehicle cooling system of claim 1, wherein the oil cooler is an air-cooled oil cooler that causes heat exchange between oil and air. 8. The vehicle cooling system according to claim 1, wherein: - the vehicle cooling system is installed in the vehicle, which includes an electric motor and an engine as sources of driving power; - the first oil pump is an electric oil pump, which must be driven by an electric motor; and - the second oil pump is a mechanical oil pump, which must be driven by an engine. 9. The vehicle cooling system of claim 8, wherein the second circuit further includes a three-phase heat exchanger configured to permit heat exchange between the engine cooling water and oil discharged from the second oil pump, and allows heat exchange between the engine oil and oil produced from a second oil pump. 10. The vehicle cooling system according to claim 9, further comprising: a first switching valve provided in a circuit in which cooling water for the engine circulates, the first switching valve switching between an open state in which the flow of cooling water for the engine through the heat exchanger is allowed and a closed state in which the flow of cooling water for the engine through the heat exchanger not allowed; and a second switching valve provided in a circuit in which engine oil circulates, the second switching valve switching between an open state in which the oil flow to the engine through the heat exchanger is allowed and a closed state in which the oil flow to the engine through the heat exchanger is not allowed. 11. The vehicle cooling system according to claim 10, further comprising: - the first oil temperature sensor that detects the temperature of the oil; - a water temperature sensor that detects the temperature of the cooling water for the engine; - a second oil temperature sensor that detects the temperature of the oil for the engine; and - a control module, configured to control the opening-closing of each of the first switching valve and the second switching valve based on the oil temperature determined by the first oil temperature sensor, the cooling water temperature for the engine, determined by the water temperature sensor, and the oil temperature for the engine, detected by a second oil temperature sensor, - while the control module is configured to, when the oil temperature is below a predetermined oil temperature, control at least a second switching valve from among the first switching valve and the second switching valve so that it is in the open state, and perform heating control in this way to increase the temperature of the oil through heat transfer in the heat exchanger. 12. The vehicle cooling system according to claim 11, in which the control module is configured to, if the control module performs heating control when the cooling water temperature for the engine is higher than the predetermined water temperature, control the first switching valve and the second switching valve in this way that they are in open states. 13. The vehicle cooling system according to claim 11 or 12, wherein the control module is configured to, if the control module performs heating control, when the temperature of the cooling water for the engine is equal to or lower than the predetermined water temperature and the oil temperature is lower than the oil temperature for the engine, control the first switching valve so that it is in the closed state, and control the second switching valve so that it is in the open state.

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