KR101899221B1 - Vehicular cooling system - Google Patents

Abstract

The cooling system 100 including the oil circulation circuit 200 includes an inverter 21 and a transmission oil pump 102 for discharging oil as a refrigerant supplied to each of the motors 2 and 3, And a HV radiator 103 for cooling the oil supplied to each of the motors 2 and 3 and a second circuit 210 for supplying the lubricant to the lubricating portion 30 without passing through the HV radiator 103 And a second circuit (220) including a mechanical oil pump (101) for discharging the oil.

Description

VEHICULAR COOLING SYSTEM

The present disclosure relates to a vehicle cooling system.

BACKGROUND ART [0002] As a cooling system of a hybrid vehicle equipped with an engine and an electric motor, an inverter cooling circuit for cooling an inverter electrically connected to an electric motor is known. It is known that the inverter cooling circuit circulates cooling water (hybrid cooling water) as a refrigerant.

Further, an engine cooling circuit using a cooling water (engine cooling water) different from the hybrid cooling water as a refrigerant is known. Japanese Laid-Open Patent Application No. 2013-199853 discloses a cooling system having an engine cooling circuit, a transaxle cooling circuit using oil as a refrigerant, and heat exchange between engine coolant and oil is performed by a heat exchanger.

The hybrid vehicle may be equipped with a cooling system having an inverter cooling circuit, an engine cooling circuit and a transaxle cooling circuit. In each of the cooling circuits described above, dedicated liquids such as hybrid cooling water, engine cooling water and oil are circulated in respective independent flow paths. Therefore, the number of components included in each cooling circuit is increased, and the cooling system as a whole is increased in size.

Further, in the transaxle cooling circuit described in JP 2013-199853A, a portion (lubricating-requiring portion) requiring oil lubrication or oil warming (a portion requiring lubrication) and a portion requiring cooling Part). It is necessary to supply warm oil to the transmission gear or the like included in the lubricating-requiring portion in order to reduce the stirring resistance of the oil. On the other hand, it is necessary to supply the low-temperature oil to the electric motor included in the cooling-required portion in order to cool the electric motor.

However, in the configuration of JP 2013-199853A, the oil of the transaxle cooling circuit is supplied irrespective of the lubrication-required portion and the cooling-required portion in the transaxle case. Thus, if cooling is preferred over lubrication, the part to be warmed (lubrication-required) is also cooled simultaneously with the part to be cooled (cooling-required). On the other hand, when lubrication is preferred over cooling, the portion to be cooled (cooling-required portion) is also warmed at the same time as the portion to be warmed (lubrication-required portion).

The present disclosure provides a cooling system for a vehicle that enables miniaturization of the cooling system and ensures both cooling performance and lubrication performance.

A vehicle cooling system according to an aspect of the present disclosure is mounted on a vehicle having an electric motor, an inverter electrically connected to the electric motor, and a power transmitting mechanism for transmitting power output from the electric motor to the wheel. The vehicle cooling system includes an oil circulation circuit. The oil circulation circuit includes a first oil pump for sucking the oil stored in the oil reservoir and the oil reservoir and discharging the oil as a refrigerant supplied to the inverter and the electric motor, A first circuit including an oil cooler for cooling the oil supplied to the inverter and the electric motor, and a second circuit including an oil cooler for absorbing the oil stored in the oil reservoir, And a second circuit having a second oil pump for discharging the oil supplied to the necessary portion.

According to this aspect, only the oil is circulated in the oil circulation circuit including the inverter and the electric motor. Thus, the vehicle cooling system can be downsized. Further, as the cooling circuit, the first circuit cools the oil discharged from the first oil pump through the oil cooler, and supplies the oil to the inverter or the electric motor. As the lubrication circuit, the second circuit supplies the oil discharged from the second oil pump to the lubrication-requiring portion without being cooled by the oil cooler. Therefore, both the cooling performance and the lubrication performance can be secured.

In this aspect, in the first circuit, the inverter and the electric motor may be installed on the downstream side of the first oil pump, the inverter and the electric motor may be connected in series, and the electric motor may be installed on the downstream side of the inverter have.

According to this aspect, the first circuit includes an inverter between the oil cooler and the electric motor on the downstream side of the first oil pump. When the heat resistance temperature of the electric motor and the inverter are compared, the heat resistance temperature of the inverter is low. According to the cooling system, the first circuit can supply the oil cooled in the oil cooler to the inverter in preference to the electric motor.

In this aspect, in the first circuit, the inverter and the electric motor may be installed on the downstream side of the first oil pump, and the inverter and the electric motor may be connected in parallel.

According to this aspect, the first circuit can supply the oil cooled by the oil cooler to the electric motor without passing through the inverter, on the downstream side of the first oil pump. Therefore, the temperature of the oil supplied to the electric motor does not increase as a result of heat exchange with the inverter, and the electric motor can be cooled by the low temperature oil.

In this aspect, the electric motor may include a stator and a rotor, and in the first circuit, the electric motor cooling pipe for supplying oil to the electric motor may have a discharge hole for discharging oil towards the stator. Further, the oil flowing in the first circuit may have insulating property.

In this embodiment, the inverter can be configured so that the oil discharged from the first oil pump flows as refrigerant inside.

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

In this embodiment, the oil cooler may be an air-cooled oil cooler that performs heat exchange between oil and air.

According to this aspect, the oil discharged from the first oil pump is cooled by the air-cooled oil cooler, and thus the coolability of the oil is improved.

The vehicular cooling system according to this aspect can be mounted on a vehicle having an electric motor and an engine as a power source. The first oil pump may be an electric oil pump driven by an electric motor, and the second oil pump may be a mechanical oil pump driven by an engine.

According to this aspect, the first oil pump is constituted by the electric oil pump, and therefore, even if the engine is stopped, the first oil pump can be driven. Further, the discharge amount of the first oil pump can be controlled by a control unit such as an electronic control unit.

In this aspect, the second circuit further comprises a three-phase heat exchanger configured to be heat exchangeable between the oil discharged from the second oil pump and the engine coolant water, and heat exchangeable between the oil discharged from the second oil pump and the engine oil .

According to this aspect, the three-phase heat exchanger enables heat exchange between the oil discharged from the second oil pump and the engine cooling water, and also enables heat exchange between the oil discharged from the second oil pump and the engine oil. Thus, the oil via the three-phase heat exchanger can be supplied to the lubricant-requiring portion.

In this aspect, the vehicle cooling system is installed in a circuit in which the engine coolant is circulated, and is provided with a first switch that is switched between an open state in which the engine coolant can flow through the heat exchanger and a closed state in which the engine coolant can not flow through the heat exchanger. And a second switching valve installed in a circuit through which the engine oil circulates and which is switched between an open state where the engine oil can flow through the heat exchanger and a closed state where the engine oil can not flow through the heat exchanger .

According to this aspect, the heat exchange state in the three-phase heat exchanger can be controlled by switching between the first switch valve and the second switch valve between the open state and the closed state.

In this aspect, the vehicle cooling system includes a first oil temperature sensor for detecting the temperature of the oil, a water temperature sensor for detecting the temperature of the engine coolant, a second oil temperature sensor for detecting the temperature of the engine oil, Controls the opening and closing of the first switching valve and the second switching valve based on the temperature of the oil detected by the first oil temperature sensor, the temperature of the engine cooling water detected by the water temperature sensor, and the temperature of the engine oil detected by the second oil temperature sensor And may further comprise a control unit. The control unit controls at least the second switch valve among the first switch valve and the second switch valve to be in an open state when the temperature of the oil is lower than a predetermined oil temperature, To perform the warming control.

According to this aspect, the oil supplied to the lubrication-requiring portion receives heat from at least one of the engine coolant and the engine oil, thereby warming it. Therefore, the temperature rise of the oil is accelerated, and the lubrication-required portion can be warmed up early. Therefore, the dragging loss and / or the stirring loss generated in the lubricating-required portion by the oil can be reduced, and the fuel consumption can be improved.

In this aspect, the control unit may be configured to control the first switch valve and the second switch valve to be in the open state when the temperature of the engine coolant is higher than a predetermined water temperature when the control unit performs the warming control.

According to this aspect, the oil supplied to the lubrication-requiring portion warms by receiving the heat of the engine cooling water and the engine oil, so that the temperature rise of the oil becomes faster and the lubrication-requiring portion can be warmed early. Therefore, the dragging loss and / or the stirring loss generated in the lubrication-required portion by the oil can be reduced, and the fuel consumption can be improved. Further, the heat exchange state in the three-phase heat exchanger is switched in consideration of the temperature of the engine cooling water, and adverse effects on the engine side due to heat exchange in the heat exchanger can be suppressed.

In this aspect, when the control unit performs the warming control, the control unit controls the first switch valve to be in the closed state when the temperature of the engine coolant is below the predetermined water temperature and the temperature of the oil is lower than the temperature of the engine oil And to control the second switch valve to be in an open state.

According to this aspect, the heat exchange state in the three-phase heat exchanger is switched in consideration of the temperature of the engine cooling water, and adverse effects on the engine side due to heat exchange in the heat exchanger can be suppressed. That is, when the temperature of the engine coolant is lower than the predetermined water temperature and therefore the warming of the engine coolant is required, the first switch valve is also closed during the warming control for warming the oil of the second circuit, It is possible to inhibit the oil in the circuit from being stolen.

In this aspect, the oil circuit includes a first circuit (cooling circuit) including an inverter and an electric motor, and a second circuit (lubrication circuit) including a lubrication-requiring portion. Since the oil circulation circuit circulates only the oil, the vehicle cooling system can be miniaturized as compared with the conventional neck where the inverter cooling circuit circulating the cooling water and the transaxle cooling circuit circulating the oil are separated from each other. In addition, the first circuit can supply the oil cooled in the oil cooler to the inverter and the electric motor, and the second circuit can supply the oil without passing through the oil cooler to the lubricant-requiring portion. Thus, the cooling system can ensure both cooling performance and lubrication performance.

The features, advantages, and technical and industrial significance of the exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which like reference numerals designate like elements.
1 is a skeleton view showing an example of a vehicle equipped with a vehicle cooling system.
2 is a schematic diagram showing a schematic configuration of a cooling system according to the first embodiment.
3 is a diagram for explaining a comparison between the kinematic viscosity of the oil used in the cooling system according to the first embodiment and the kinematic viscosity of the conventional oil.
4 is a view for explaining the relationship between the pump discharge amount and the oil temperature.
Fig. 5 is a schematic view showing a schematic configuration of a cooling system according to a modification. Fig.
6 is a schematic diagram showing a schematic configuration of a cooling system according to the second embodiment.
7 is a diagram for explaining the relationship between the T / M unit loss and the T / M oil temperature.
8 is a diagram showing a change in liquid temperature in a normal running state.
9 is a flowchart showing an example of the heat exchange control of the second embodiment.
10 is a schematic diagram showing a schematic configuration of a cooling system according to a reference example.
11 is a view for explaining a cooling system according to another reference example.

Referring to the drawings, a vehicle cooling system according to an embodiment of the present disclosure will be specifically described below.

[First Embodiment]

[One. Vehicle] Fig. 1 is a skeleton view showing an example of a vehicle equipped with a vehicle cooling system. The vehicle Ve is a hybrid vehicle having an engine 1, a first motor MG1, and a second motor MG2. The engine 1 is a well-known internal combustion engine. The motors 2 and 3 are well-known motor-generators having motor functions and generating functions. Each of the motors 2 and 3 is electrically connected to the battery 22 via an inverter 21. Further, each of the motors 2, 3 is a cooling-required part in the transaxle case 40. [ The inverter 21 is disposed outside the transaxle case 40.

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

The input shaft 6, the power split mechanism 5, and the first motor 2 are disposed coaxially with the crankshaft of the engine 1. [ The crankshaft and the input shaft 6 are coupled through a torque limiter or the like not shown. The first motor 2 is disposed adjacent to the power dividing mechanism 5 on the side opposite to the engine 1 in the axial direction. The first motor 2 has a stator 2a, a rotor 2b and a rotor shaft 2c wound with coils.

The power split device 5 is a differential mechanism having a plurality of rotary elements, and is formed by a single pinion planetary gear mechanism in the example shown in Fig. The power split device 5 includes three sun gears 5S as external gears and a ring gear 5R as an internal gear disposed concentrically with the sun gear 5S and a sun gear 5S, And a carrier 5C that rotatably holds the pinion gear engaged with the pinion gear 5R in a revolvable manner around the sun gear 5S.

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

The output gear 7 is coupled to the differential gear mechanism 9 via the counter gear mechanism 8. [ The counter gear mechanism 8 includes a counter shaft 8a disposed in parallel with the input shaft 6, a counter driven gear 8b engaged with the output gear 7, and a ring gear 9a of the differential gear mechanism 9 And a counter drive gear 8c engaged with the counter drive gear 8c. The counter driven gear 8b and the counter drive gear 8c are attached to the counter shaft 8a so as to rotate integrally. The wheel 4 is coupled to the differential gear mechanism 9 via the left and right drive shafts 10.

The vehicle Ve is configured to add the torque output by the second motor 3 to the torque transmitted from the engine 1 to the wheel 4. [ The second motor 3 has a stator 3a, a rotor 3b, and a rotor shaft 3c wound around a coil. The rotor shaft 3c is disposed in parallel with the counter shaft 8a. The reduction gear 11 engaged with the counter driven gear 8b is attached to the rotor shaft 3c so as to rotate integrally with the rotor shaft 3c.

A mechanical oil pump (MOP) 101 driven by the engine 1 is installed in the vehicle Ve. The mechanical oil pump 101 has a pump rotor (not shown) disposed coaxially with the crankshaft of the engine 1 and rotating integrally with the input shaft 6. For example, when the vehicle Ve advances by the power of the engine 1, the pump rotor of the mechanical oil pump 101 rotates in the forward direction by the torque of the input shaft 6, 101 discharge oil from the discharge port. The oil discharged from the mechanical oil pump 101 is supplied to the lubricant-requiring portion 30 (for example, shown in Fig. 2) in the transaxle case 40 and functions as a lubricating oil. The lubrication-requiring portion 30 is a portion of the power transmission mechanism of the vehicle Ve, a portion (mainly, a gear) that requires oil lubrication and oil warming in the transaxle case 40. [ The power transmitting mechanism is a mechanism for transmitting the power output from the power source (the engine 1, the first motor 2 and the second motor 3) of the vehicle Ve to the wheel 4. 1, the lubrication-requiring portion 30 includes a power dividing mechanism 5, an output gear 7, and a counter gear mechanism 8. In the vehicle Ve shown in Fig.

[2. Cooling System] Fig. 2 is a schematic diagram showing a schematic configuration of a cooling system 100 for a vehicle according to the first embodiment. A vehicle cooling system 100 (hereinafter simply referred to as a " cooling system ") 100 is mounted on the vehicle Ve shown in FIG. 1, and uses the transmission lubricating oil (T / M lubricating oil) Respectively. In the present description, the transmission lubricating oil (T / M lubricating oil) is simply referred to as " oil ".

As shown in FIG. 2, the cooling system 100 includes an oil circulation circuit 200 for circulating oil. The oil circulation circuit 200 includes a first circuit (hereinafter referred to as a " cooling circuit ") 210 for cooling the inverter 21 and the respective motors 2,3, and a lubricant- (Hereinafter referred to as " lubrication circuit ") 220 for lubrication and warming the semiconductor device.

More specifically, the oil circulation circuit 200 supplies the oil to the cooling-required portion in the transaxle case 40 included in the transaxle flow path and the oil path (inverter flow path) for supplying the oil as the refrigerant to the inverter 21, And the cooling flow path communicating with each other communicate with each other. That is, only one identical liquid, called oil, circulates in the oil circulation circuit 200 including the inverter flow path and the transaxle flow path. In addition, the cooling system 100 pumps the oil in the oil circulation circuit 200 toward the supply source by two oil pumps.

[2-1. Cooling circuit] The cooling circuit 210 includes an electric oil pump 102 as a first oil pump, a radiator dedicated to hybrid (hereinafter referred to as "HV radiator") 103, an inverter 21 as a cooling object, Motors 2 and 3, and an oil reservoir 104. [ The cooling circuit 210 cools the oil discharged from the electric oil pump 102 by the HV radiator 103 and supplies the oil to the inverter 21 and the motors 2 and 3.

The electric oil pump 102 is driven by an electric motor (not shown). The electric motor is driven under the control of a control unit (ECU) 150. The control unit 150 has a well-known electronic control unit and controls the driving of the electric oil pump 102. [ The electric oil pump 102 is driven under the control of the control unit 150 and sucks the oil stored in the oil reservoir 104 and discharges the oil from the discharge port. The electric oil pump 102 discharges oil supplied as a refrigerant to an object to be cooled (the inverter 21 and the motors 2 and 3). A first discharge passage (201) is connected to a discharge port of the electric oil pump (102). The oil discharged into the first discharge passage 201 by the electric oil pump 102 is supplied to the inverter 21 and the motors 2 and 3 as the oil supply sources in the cooling circuit 210 by the discharge pressure of the electric oil pump 102, 3). ≪ / RTI >

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, the outside air of the vehicle Ve). That is, the HV radiator 103 is an air-cooling type oil cooler disposed outside the transaxle case 40. The oil flowing in the HV radiator 103 dissipates heat by exchanging heat with the outside air of the vehicle Ve. The HV radiator 103 is installed in the cooling circuit 210 between the electric oil pump 102, the inverter 21 and the motors 2 and 3. The cooling circuit 210 air-quenches (cools) the oil pumped from the electric oil pump 102 to the inverter 21 and the motors 2, 3 by the HV radiator 103. A first discharge passage 201 is connected to an inlet of the HV radiator 103 and a first supply passage 202 is connected to an outlet of the HV radiator 103.

The first supply flow path 202 is a flow path between the HV radiator 103 and the inverter 21. This flow path can supply the oil 21 air-cooled by the HV radiator 103 to the inverter 21. [ The inlet of the case of the inverter 21 is connected to the first supply flow path 202. The oil that has been air-cooled by the HV radiator 103 flows into the case of the inverter 21 from the first supply flow passage 202 and comes into direct contact with the heat generating portion of the inverter 21 to perform direct heat exchange with the heat exchanging portion And the inverter 21 is cooled.

The second supply passage 203 is connected to the outlet of the case of the inverter 21. [ The second supply flow path 203 is a flow path between the inverter 21 and the motors 2 and 3. The flow path allows the oil air pumped by the HV radiator 103 to be supplied to the motors 2 and 3 have. In the cooling circuit 210, the inverter 21 and the motors 2 and 3 are connected in series on the downstream side of the electric oil pump 102, and the respective motors 2 and 3 are connected to the downstream side of the inverter 21 , 3) are installed. Each of the motors 2 and 3 is disposed inside the transaxle case 40 so that the oil supplied to each of the motors 2 and 3 passes through the HV radiator 103 and the inverter 21, And flows outside the axle case 40.

In the example shown in Fig. 2, the second supply flow passage 203 is a flow passage branched from the downstream side. The second supply passage 203 is provided with the MG1 cooling pipe 203a and the MG2 cooling pipe 203b. The MG1 cooling pipe 203a forms one branch flow path, and supplies the oil to the first motor 2. The MG2 cooling pipe 203b forms another branch oil passage and supplies the oil to the second motor 3. [ More specifically, the MG1 cooling pipe 203a has a structure having a discharge hole for discharging oil toward the stator 2a in order to cool the stator 2a that generates heat in the first motor 2, particularly during energization . The MG2 cooling pipe 203b has a structure having an ejection hole for ejecting oil toward the stator 3a in order to cool the stator 3a that generates heat in the second motor 3, particularly during energization. Each of the cooling pipes 203a and 203b is disposed in the transaxle case 40.

The oil flowing in the cooling circuit 210 from the electric oil pump 102 toward each of the motors 2 and 3 cools each of the motors 2 and 3 and then flows into the oil storage (104). The oil reservoir 104 is formed by an oil pool or an oil pan formed at the bottom of the transaxle case 40, for example. For example, after cooling each of the motors 2 and 3, the oil returns to the oil reservoir 104 installed at the bottom of the transaxle case 40, for example, by gravity. As described above, when oil circulates in the cooling circuit 210, the oil stored in the oil reservoir 104 is supplied to the inverter 21 in the cooling circuit 210 by the electric oil pump 102, And after returning to the oil reservoir 104 after each of the motors 2 and 3 has cooled down.

[2-2. Lubricating Circuit] The lubrication circuit 220 includes a mechanical oil pump 101 which is a second oil pump, a lubrication-requiring portion 30 which is a lubrication target, and an oil storage portion 104. The lubrication circuit 220 supplies the oil discharged from the mechanical oil pump 101 to the lubrication-requiring portion 30 without air-cooling the oil by using the HV radiator 103.

The mechanical oil pump 101 is configured to be driven by the engine 1 (shown in Fig. 1), sucks the oil stored in the oil reservoir 104, and discharges oil from the discharge port. The mechanical oil pump 101 discharges oil supplied as lubricating oil to the lubricating-requiring portion 30 (gear). The third supply passage 204 is connected to the discharge port of the mechanical oil pump 101. The third supply passage 204 includes a second discharge passage connected to the discharge port of the mechanical oil pump 101 and a lubricating passage for supplying the oil to the lubricant-requiring portion 30 on the downstream side of the second discharge passage . The oil discharged from the mechanical oil pump 101 to the third supply passage 204 is pumped by the discharge pressure of the mechanical oil pump 101 toward the lubrication-requiring portion 30 in the lubrication circuit 220. The mechanical oil pump 101 is installed inside the transaxle case 40 so that the entire path of the lubrication circuit 220 is formed inside the transaxle case 40. For example, the third supply passage 204 (lubricating passage) is a passage (shaft core passage) formed inside the input shaft 6 shown in FIG. 1 and includes a discharge hole formed in the input shaft 6 . The oil pumped from the mechanical oil pump 101 toward the lubrication-requiring portion 30 in the lubrication circuit 220 flows from the third supply passage 204 (the discharge hole of the input shaft 6) (Lubrication-requiring portion 30). The oil discharged from the third supply passage 204 lubricates a plurality of gears in the transaxle case 40.

After lubrication of the lubrication-requiring portion 30, the oil flows into the oil storage portion 104 in the transaxle case 40. For example, after lubrication of the lubrication-requiring portion 30, the oil is returned to the oil reservoir portion 104 by, for example, gravity or rotational force of the gear (centrifugal force). As described above, when the oil circulates in the lubrication circuit 220, the oil stored in the oil reservoir 104 is pumped through the interior of the lubrication circuit 220 by the mechanical oil pump 101, After lubricating the lubrication-requiring portion 30, the lubricating oil is returned to the oil reservoir portion 104.

Here, the lubrication-requiring portion 30 includes another gear which is lubricated by the oil lubricated with the predetermined gear. For example, in the vehicle Ve shown in Fig. 1, a third supply passage 204 (mainly a lubrication passage) is formed inside the input shaft 6, and a power split mechanism 5) (the sun gear 5S, the ring gear 5R and the pinion gear) is moved by gravity or centrifugal force, for example, and the other gears (the output gear 7 and the counter gear mechanism 8) Lubricate. The differential gear mechanism 9 can be configured such that a part of the gears is immersed in the oil in the oil reservoir 104 and receives the oil to lubricate the differential gear mechanism 9 thereby. Further, depending on the structure of the transaxle case 40, the oil can be returned to the oil reservoir 104 before the oil lubricated by the power splitting mechanism 5 is lubricated with the differential gear mechanism 9. [ Therefore, the differential gear mechanism 9 may not be included in the lubricant-requiring portion 30. [

[3. Comparison with Reference Example Here, in order to illustrate the advantages of the cooling system 100, the cooling system 100 and the reference example will be compared. First, referring to Fig. 10, a cooling system according to a reference example will be described. Next, a comparison between the cooling system 100 and the reference example will be described.

[3-1. Reference Example] Fig. 10 is a schematic diagram showing a schematic configuration of a cooling system 300 according to a reference example. In the cooling system 300 according to the reference example, the inverter cooling circuit 310 and the transaxle flow path 320 are formed by independent flow paths, respectively. The inverter cooling circuit 310 is formed by a channel in which hybrid cooling water (LLC) is circulated as a refrigerant. The transaxle flow path 320 is formed by a flow path through which the lubricating oil (T / M lubricating oil) of the transmission is circulated as a refrigerant.

More specifically, the inverter cooling circuit 310 includes an electric water pump (EWP) 311, an HV radiator 312 that performs heat exchange between the hybrid cooling water (hereinafter referred to as " HV cooling water & An inverter 313 electrically connected to the motors 2 and 3; a heat exchanger 314 for performing heat exchange between the oil in the HV cooling water and the oil in the transaxle oil passage 320; and a storage tank 315 ). The inverter cooling circuit 310 is a circulation channel for cooling the inverter 313 using HV cooling water.

In the inverter cooling circuit 310, the electric water pump 311 sucks the HV cooling water stored in the storage tank 315, and discharges the HV cooling water from the discharge port. The HV cooling water discharged from the electric water pump 311 is air-cooled by the HV radiator 312 and then supplied to the inverter 313. [ The inverter 313 is cooled by the HV cooling water that is air-cooled by the HV radiator 312. After cooling the inverter 313, the HV cooling water is pumped into the storage tank 315 after entering the heat exchanger 314 and performing heat exchange with the oil.

The transaxle flow path 320 includes a mechanical oil pump 321, a heat exchanger 314, a first motor 2, a second motor 3, a lubrication-requiring portion 30 and an oil reservoir 322 do. The transaxle flow path 320 is a path through which oil can be supplied to each of the motors 2 and 3 after the heat exchange by the heat exchanger 314 between the oil discharged from the mechanical oil pump 321 and the HV cooling water ). The transaxle flow path 320 is a flow path for supplying the oil discharged from the mechanical oil pump 321 to the lubrication-requiring portion 30 without performing the heat exchange with the HV cooling water by the heat exchanger 314. [ (Lubricating flow path). Unlike the oil reservoir 104 according to the first embodiment described above, the oil stored in the oil reservoir 322 is oil that is not supplied to the HV radiator 312 and the inverter 313.

[3-2. COMPARISON The cooling system 100 according to the first embodiment is advantageous over the cooling system 300 first, in terms of cooling performance, and secondly in terms of structure.

[3-2-1. Cooling performance] Pay attention to the cooling performance of the inverter. The common point between the first embodiment and the reference example is that the inverter element energized in the inverter 21 or 313 is a heat generating portion (heat source).

In the inverter cooling circuit 310 according to the reference example, the HV cooling water as the refrigerant has conductivity, and therefore, in consideration of safety, the HV cooling water can not come into contact with the inverter element (inverter heat generating portion) that is energized. In the heat exchange between the inverter heat generating section and the HV cooling water, it is necessary to provide an insulating plate (intervening member) such as a heat sink between the inverter heat generating section and the HV cooling water. Therefore, the cooling of the inverter heat generating portion by the HV cooling water is indirect cooling through the insulating plate, so that the heat resistance of the portion between the HV cooling water and the inverter heat generating portion is increased by the amount of the insulating plate. For example, when a heat transfer member is installed in the heat transfer path from the inverter element to the insulating plate (heat sink), the heat resistance is increased by the amount of the heat transfer member. In addition, the heat conductivity of the inverter elements may be deteriorated due to the heat conductivity between the members included in the heat transfer path as well as the thermal conductivity of the members themselves.

In the cooling system 100 according to the first embodiment, the oil which is a refrigerant has insulation property, and therefore, when the oil cools the inverter 21, the oil can be brought into contact with the inverter element (inverter heat generating portion) . In the cooling system 100, direct heat exchange may be performed between the inverter heat generating portion and the oil (refrigerant). That is, the cooling system 100 can directly cool the inverter element by a refrigerant having an insulation property. Therefore, unlike the reference example, the cooling system 100 does not require an insulating plate such as a heat sink, and the thermal resistance between the refrigerant (oil) and the inverter heat generating portion can be reduced as compared with the reference example. Therefore, the first embodiment provides an improvement in the cooling property of the inverter element and hence an improvement in the cooling performance of the inverter 21 as compared with the reference example. In addition, the heat resistance performance of the inverter 21 is improved due to the improvement of the cooling property of the inverter element. Here, the inverter element is a package covered with a housing.

In addition, the cooling system 300 according to the reference example is configured such that the oil is pumped to both the motors 2, 3 (cooling-required portion) and the lubricant-requiring portion 30 by one mechanical oil pump 321 . Therefore, it becomes difficult to control the amount of oil supplied to the cooling-required portion and the amount of oil supplied to the lubricant-requiring portion 30. For example, in the case of a vehicle in which oil-warming of the lubrication-requiring portion 30 is required (warming is emphasized), such as during cold start of the vehicle Ve, oil is supplied to the lubrication- Despite the drive of the mechanical oil pump 321, a portion of the oil is supplied to the cooling-required portion (motors 2, 3). This can reduce the amount of oil supplied for warming. In this case, the oil is supplied to the cooling-requiring portion, which requires less cooling. This can increase the loss (stirring loss) generated as a result of stirring the oil by the rotor rotation of each of the motors 2, 3 and the loss (dragging loss) caused by the rotor dragged by the oil. Or when the vehicle requires cooling of at least one of the first motor 2 and the second motor 3 (cooling is emphasized) A portion of the oil is supplied to the lubrication-requiring portion 30 even though the mechanical oil pump 321 is driven to supply the lubricating oil. As a result, the amount of oil supplied as a coolant is reduced, and the cooling performance of the motors 2 and 3 may be reduced. In addition, an excessive amount of oil can be supplied to the lubrication-requiring portion 30, so that the agitation loss and the dragging loss generated in the lubrication-requiring portion 30 can be increased. As described above, the increase in the agitation loss and the dragging loss in the motor components (each of the motors 2 and 3) and the lubricating component (lubrication-requiring portion 30) caused by the oil may deteriorate the fuel consumption have.

Further, in the cooling system 300 according to the reference example, the oil in the transaxle flow path 320 releases heat to the HV cooling water in the inverter cooling circuit 310 via the heat exchanger 314. That is, the HV cooling water is air-cooled by the HV radiator 312, that is, the heat of the oil is dissipated to the HV radiator 312 via the HV cooling water. Therefore, the heat dissipation efficiency of the oil is poor. This can reduce the cooling effect of each motor 2, 3 by the oil.

The components (the inverter 21 and the motors 2 and 3) that need to be cooled by the oil circulation circuit 200 having the cooling circuit 210 and the lubrication circuit 220 in the first embodiment, The necessary components (lubricant-requiring portions 30) may be supplied with oils having different temperatures respectively. The electric oil pump 102 as the first oil pump provided in the cooling circuit 210 and the mechanical oil pump 101 as the second oil pump provided in the lubrication circuit 220 can be separately driven. For example, when the vehicle Ve requires cooling of the motors 2 and 3 (cooling is emphasized), such as when the vehicle Ve is moving at high speed or moving uphill, the electric oil pump 102 May be driven under the control of the control unit 150. [ Thus, the cooling system 100 can ensure both cooling performance and lubrication performance.

In the cooling system 100 according to the first embodiment, the electric oil pump 102 is also intended to supply oil to the inverter 21 and the motors 2, 3 in the cooling circuit 210, 150). Therefore, the electric oil pump 102 can control the oil temperature in consideration of the inverter temperature and the motor temperature. On the other hand, in the reference example, the electric water pump 311 for the inverter cooling circuit 310 and the mechanical oil pump 321 for the transaxle flow path 320 are provided, so that the inverter temperature and the motor temperature are separately controlled. Therefore, according to the first embodiment, compared with the reference example, the control for providing the optimum oil temperature according to the traveling state of the vehicle Ve can be performed more easily.

[3-2-2. Structure] With respect to the structure, according to the first embodiment, the number of constituent elements can be reduced as compared with the reference example. For example, in the reference example, a part of the pipe included in the heat exchanger 314, the reservoir tank 315, and the water channel may be omitted. In addition, the first embodiment does not require HV cooling water, which is a constituent element of the inverter cooling circuit 310 in the reference example, so that one refrigerant can be omitted. In summary, the cooling system 100 according to the first embodiment requires only one refrigerant (oil only), thus eliminating the need to provide redundant components to provide a compact and lightweight system configuration have. In addition, omission of components (including HV cooling water) can reduce costs. In addition, the large-sized cooling system 300 has poor vehicle mountability and poor assemblability.

[3-2-3. Oil Fluidity] Referring to Figures 3 and 4, fluidity of the oil will be described. 3 is a diagram for explaining a comparison between the kinematic viscosity of the oil used in the cooling system 100 according to the first embodiment and the kinematic viscosity of the conventional oil. 4 is a view for explaining the relationship between the pump discharge amount and the oil temperature. In this description, the oil used in the cooling system 100 is referred to as " essential oil " and the oil used in conventional cooling systems is referred to as " conventional oil ". The solid line shown in Fig. 3 represents the kinematic viscosity of the present oil, and the broken line represents the kinematic viscosity of the conventional oil. The solid line shown in Fig. 4 shows the discharge amount (flow rate) in this oil, and the broken line shows the discharge amount (flow rate) in the conventional oil.

As shown in Fig. 3, the kinematic viscosity of the present oil is lower than the kinematic viscosity of the conventional oil at any oil temperature, and is significantly lowered, particularly in the low temperature range. More specifically, in the oil temperature range where the oil temperature is negative, the kinematic viscosity of the present oil is considerably lower than that of the conventional oil. In the oil temperature range where the oil temperature is positive, this oil shows a large viscosity drop. For example, at an oil temperature range of about 10 to 30 占 폚, the oil exhibits 60% kinematic viscosity drop over conventional oils.

Therefore, by using the main oil of low viscosity as the cooling system 100, it is possible to reduce the pressure loss generated when the main oil flows through the oil circulation circuit 200. [ Thus, the oil can be flowed as refrigerant into the inverter 21 while suppressing an increase in pressure loss. Further, the dragging resistance generated by the oil is reduced in the rotating member such as the rotor and the lubricant-requiring portion 30 of each of the motors 2 and 3 in contact with the oil. Thereby, the oil temperature range in which the electric oil pump 102 is operable can be extended to the cryogenic region. That is, the operating limit oil temperature of the electric oil pump 102 is lowered to a very low temperature. The operation limit oil temperature is the oil temperature at which the discharge amount (flow rate per unit time) from the electric oil pump 102 reaches the required discharge flow rate. Fig. 4 shows the difference between this oil and the conventional oil, relative to the operating limit oil temperature of the electric oil pump 102. Fig.

As shown in FIG. 4, the operating limit oil temperature (Tlim) of the electric oil pump 102 discharging the present oil is a cryogenic temperature of minus several tens of degrees Celsius. The operating limit oil temperature (Tlim) of the electric oil pump 102 is approximately -40 캜 to -20 캜. On the other hand, the operating limit oil temperature of the electric oil pump 102 for discharging the conventional oil is about 0 degrees Celsius. As described above, the oil temperature range in which the electric oil pump 102 is operable is extended to a cryogenic region including minus several tens degrees. Therefore, the fluidity of the present oil is secured even if the outside air temperature is extremely low at about minus 30 캜. In addition, when this oil is used, the discharge amount is larger at an arbitrary oil temperature than that at the time when a conventional oil is used, and shows a considerable increase particularly in the low temperature range.

As described above, the cooling system 100 according to the first embodiment has the oil circulation circuit 200 in which only the oil is circulated through the inverter flow path and the transaxle flow path. Thereby, the cooling system 100 can be downsized. In the oil circulation circuit 200, the oil air cooled by the HV radiator 103 can be supplied to the inverter 21 and the motors 2 and 3 (cooling-required portion) by the cooling circuit 210, The oil not air-enriched by the HV radiator 103 can be supplied to the lubricant-requiring portion 30 by the lubricating circuit 220. Thereby, the cooling system 100 can secure both the cooling performance and the lubrication performance. Further, the oil can be cooled (air-cooled) by the HV radiator 103, and thus the cooling performance of the oil is improved. In addition, the air-cooled oil is supplied to the respective motors 2, 3, thus improving the cooling of the motors 2, 3. Further, in the cooling circuit 210, either the inverter 21 or the motor 2, 3 is aligned in series. Thus, the reduction in the amount of oil supplied to the motors 2 and 3 can be suppressed.

Further, by improving the coolability of the oil, the loss (copper loss and iron loss) of each of the motors 2 and 3 is reduced, whereby the fuel consumption is improved and the heat resistance of each of the motors 2 and 3 is improved. In addition, the cooling property of the inverter 21 is also improved, so that the loss (for example, copper loss) of the inverter 21 can be reduced, thereby improving the fuel economy and improving the heat resistance of the inverter 21. [

 [4. 5 is a schematic diagram showing a schematic configuration of a cooling system 100 according to a modified example. In the description of the modification example, the components similar to the first embodiment described above are provided with the same reference numerals as the first embodiment described above, and the description thereof will be omitted.

5, the inverter 21 and the respective motors 2 and 3 are connected to an electric oil pump (not shown) in the cooling circuit 210 of the oil circulation circuit 200. In the cooling system 100 according to the modification, 102 on the downstream side. More specifically, in the cooling circuit 210, the inverter 21, the first motor 2, and the second motor 3 are arranged in parallel.

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

The cooling system 100 according to the modification can supply the oil air cooled by the HV radiator 103 to each of the motors 2 and 3 without passing through the inverter 21. [ Thus, the increase in the temperature of the oil supplied to each of the motors 2 and 3 is prevented by the cooling of the inverter 21, and the motors 2 and 3 can be cooled by the low-temperature oil. Therefore, the cooling performance of each of the motors 2 and 3 is improved.

When the inverter 21 and the motors 2 and 3 are aligned in series as in the first embodiment described above and the inverter 21 and the motors 2 and 3 are connected in parallel Will be compared. When the inverter 21 and the respective motors 2 and 3 are aligned in series in the cooling circuit 210, compared with the case where the inverter 21 and the motors 2 and 3 are aligned in parallel, , 3) is high and the oil temperature is high. When the inverter 21 and the respective motors 2 and 3 are aligned in parallel in the cooling circuit 210, compared with the case where the inverter 21 and the motors 2 and 3 are aligned in series, (2, 3) is small and the oil temperature is low.

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 can be appropriately modified without departing from the object of the present invention.

For example, the structure and arrangement of the mechanical oil pump 101 are not particularly limited as long as they can be formed inside the transaxle case 40. For example, the mechanical oil pump 101 may not be disposed coaxially with the crankshaft of the engine 1. [ In this case, the mechanical oil pump 101 and the input shaft 6 are connected via a mechanism such as a gear mechanism or a chain mechanism so as to transmit power.

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

In the cooling system 100, the number of motors included in the cooling-required portion is not limited, and the number of cooling objects may be a number other than two. Although the first embodiment has described the case where the vehicle Ve is two motor type hybrid vehicles, the vehicle may be one motor type hybrid vehicle. Alternatively, the cooling system 100 may include three or more motors as objects to be cooled.

In addition, 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 inverter 21 to be cooled and an oil cooler that can cool the oil supplied to each of the motors 2, Therefore, there is no limitation as to whether the oil cooler is air-cooled or water-cooled. For example, if the cooling system 100 has a water-cooled oil cooler, the water-cooled oil cooler may be a heat exchanger that performs heat exchange between the oil flowing in the cooling circuit 210 and the engine coolant.

In addition, the lubrication-requiring portion 30 may include a differential gear mechanism 9. That is, whether or not the differential gear mechanism 9 is included in the lubricant-requiring portion 30 is not particularly limited.

[Second Embodiment] Next, referring to Figs. 6 to 9, a cooling system 100 according to a second embodiment will be described. The cooling system 100 according to the second embodiment includes an engine cooling water (hereinafter referred to as "ENG cooling water"), engine oil (hereinafter referred to as "ENG oil") and T / M lubricating oil (Hereinafter referred to as " heat exchanger "). In the description of the second embodiment, a description of components similar to those of the first embodiment will be omitted, and the reference numerals used in the first embodiment are used for these components.

[5. Cooling System] Fig. 6 is a schematic diagram showing a schematic configuration of the cooling system 100 according to the second embodiment. 6, the cooling system 100 according to the second embodiment includes a three-phase heat exchanger (hereinafter simply referred to as " heat exchanger ") that performs heat exchange between ENG cooling water, ENG oil, and T / (105). In the oil circulation circuit 200, the T / M oil flowing in the lubricating circuit 220 flows into the heat exchanger 105, but the T / M oil flowing in the cooling circuit 210 flows into the heat exchanger 105 So as not to flow. The lubricant circuit 220, the ENG cooling circuit 410, and the ENG oil circuit 420 are connected to the heat exchanger 105.

[5-1. Lubricating Circuit] The lubrication circuit 220 has a mechanical oil pump 101, a heat exchanger 105, a lubrication-requiring portion 30, and an oil reservoir 104. The lubrication circuit 220 supplies the oil discharged from the mechanical oil pump 101 to the lubrication-requiring portion 30 via the heat exchanger 105.

And the second discharge flow passage 206 is connected to the discharge port of the mechanical oil pump 101. The oil discharged into the second discharge passage 206 by the mechanical oil pump 101 is pumped into the heat exchanger 105 by the discharge pressure of the mechanical oil pump 101 in the lubrication circuit 220, And is pumped to the lubrication-requiring portion 30 via the heat exchanger 105.

The heat exchanger 105 is a heat exchanger configured to perform heat exchange between three liquids each of T / M oil, ENG cooling water and ENG oil. That is, the heat exchanger 105 is configured to be capable of heat exchange between the T / M oil and the ENG cooling water, and capable of heat exchange between the T / M oil and the ENG oil. Further, the heat exchanger 105 is configured to be capable of heat exchange between the ENG cooling water and the ENG oil. And the second discharge passage 206 is connected to the inlet of the heat exchanger 105 in the lubrication circuit 220. The fourth supply passage 207 is connected to the outlet of the heat exchanger 105 in the lubrication circuit 220. The fourth supply passage 207 is a lubricating passage for supplying oil to the lubricating-requiring portion 30 on the downstream side of the heat exchanger 105.

The lubrication circuit 220 is also provided with a first oil temperature sensor 151 for detecting the temperature Ttm of the T / M oil. For example, the first oil temperature sensor 151 provided in the second discharge passage 206 in the lubrication circuit 220 detects the temperature Ttm of the T / M oil discharged from the mechanical oil pump 101 . The T / M oil temperature (hereinafter referred to as " T / M oil temperature ") Ttm detected by the first oil temperature sensor 151 is supplied to the control unit 150 as a detection signal .

[5-2. ENG cooling circuit] The ENG cooling circuit 410 is a circuit in which the ENG cooling water circulates. 6, the ENG cooling circuit 410 includes a heat exchanger 105 and a first switch valve 105 for selectively blocking the flow of the ENG cooling water returned to the engine 1 via the heat exchanger 105. [ (ON-OFF valve) 411. Further, the ENG cooling circuit 410 includes a known configuration of a water pump or the like (not shown).

The first water channel 412 for supplying the ENG cooling water to the heat exchanger 105 is connected to the cooling water outlet of the engine 1 and the cooling water inlet of the heat exchanger 105. [ The second water channel 413 for supplying ENG cooling water heat exchanged by the heat exchanger 105 to the engine 1 is connected to the cooling water outlet of the heat exchanger 105 and the cooling water inlet of the engine 1. In the example shown in Fig. 6, the first switch valve 411 is installed in the second water channel 413. [

The first switching valve 411 is connected to the engine 1 via the heat exchanger 105 so as to return to the engine 1 via the heat exchanger 105 and an open state in which the ENG cooling water returned to the engine 1 can flow, (OFF) in which the flow of the ENG cooling water becomes impossible. The first switching valve 411 is constituted by, for example, an electromagnetic valve, and the opening and closing of the first switching valve 411 is controlled by the control unit 150. The ENG cooling water flows from the engine 1 toward the heat exchanger 105 in the first water channel 412 while the ENG cooling water flows through the heat exchanger 105 in the second water channel 413 And flows from the exchanger 105 toward the engine 1. [ On the other hand, when the first switching valve 411 is in the closed state, the ENG cooling circuit 410 does not cause the flow of the ENG cooling water returned to the engine 1 via the heat exchanger 105 to occur.

The ENG cooling circuit 410 is also provided with a water temperature sensor 152 for detecting the temperature of the ENG cooling water (hereinafter referred to as " ENG cooling water temperature ") Thw. The water temperature sensor 152 is installed on the upstream side of the heat exchanger 105 in the ENG oil circuit 420. Further, information on the ENG cooling water temperature Thw detected by the water temperature sensor 152 is input to the control unit 150 as a detection signal.

[5-3. ENG oil circuit] The ENG oil circuit 420 is a circuit in which the ENG oil circulates. 6, the ENG oil circuit 420 includes a heat exchanger 105 and a second switch valve 105 for selectively interrupting the flow of ENG oil returned to the engine 1 via the heat exchanger 105, (ON-OFF valve) 421, as shown in Fig.

A first flow path 422 for supplying the ENG oil to the heat exchanger 105 is connected to the ENG oil outlet of the engine 1 and the ENG oil inlet of the heat exchanger 105. A second flow path 423 for supplying ENG oil heat exchanged in the heat exchanger 105 to the engine 1 is connected to the ENG oil outlet of the heat exchanger 105 and the ENG oil inlet of the engine 1. [ In the example shown in Fig. 6, the second switching valve 421 is installed in the second flow path 423.

The second switching valve 421 is returned to the engine 1 via the heat exchanger 105 and the open state in which the ENG oil returned to the engine 1 can flow through the heat exchanger 105, (OFF) in which the flow of ENG oil is impossible. The second switching valve 421 is constituted by, for example, an electromagnetic valve, and the opening and closing of the second switching valve 421 is controlled by the control unit 150. The ENG oil flows from the engine 1 toward the heat exchanger 105 in the first flow path 422 while the ENG oil flows through the second flow path 423 inside the second flow path 423 And flows from the exchanger 105 toward the engine 1. [ On the other hand, when the second switching valve 421 is in the closed state, the flow of the ENG oil returned to the engine 1 via the heat exchanger 105 does not occur in the ENG oil circuit 420.

The ENG oil circuit 420 is also provided with a second oil temperature sensor 153 for detecting the temperature of the ENG oil (hereinafter referred to as " ENG oil temperature ") Toil. The second oil temperature sensor 153 is installed on the upstream side of the heat exchanger 105 in the ENG oil circuit 420. The information on the ENG oil temperature Toil detected by the second oil temperature sensor 153 is input to the control unit 150 as a detection signal.

[6. Control unit] Based on the detection signals (T / M oil temperature Ttm, ENG cooling water temperature Thw and ENG oil temperature Toil) input from the respective sensors 151 to 153, Closing operation of the first switching valve 411 and the second switching valve 421. That is, the control unit 150 performs the switching control for switching the first switching valve 411 and the second switching valve 421 between the open and close states and the closed state, respectively, whereby the heat in the heat exchanger 105 Control the exchange status. More specifically, the control unit 150 T / M oil temperature (Ttm), T / M oil temperature of a predetermined oil temperature (Ttm _{_1)} on (Ttm), ENG cooling water temperature (Thw), ENG cooling water temperature (Thw ) performing a comparison between the pre-determined water temperature (Thw _{_1),} and ENG oil temperature (Toil) on to carry out the switching control.

The predetermined oil temperature (Ttm _{_ 1)} is set into account the T / M unit loss. The T / M unit is connected to a drive device (first motor 2, second motor 3 and power transmission mechanism) accommodated in the transaxle case 40 and an electric component (for example, Inverter 21). Therefore, in addition to the iron loss and the copper loss that occur when the motors 2 and 3 are driven, the loss of the TM unit is reduced by the loss caused in the power transmission mechanism (for example, in the lubrication- Losses that occur). In addition, the T / M unit loss has a characteristic (temperature characteristic) that the amount of T / M unit loss varies as the T / M oil temperature Ttm changes.

7 is a diagram for explaining the relationship between the T / M unit loss and the T / M oil temperature (Ttm). A, T / M oil temperature (Ttm) a predetermined oil temperature, if included in the low oil temperature range than (Ttm _{_1),} T / M unit loss is T / M oil temperature (Ttm) as shown in Figure 7. The And is continuously reduced as it increases with the lapse of time. In contrast, when it is included in the high fluid temperature range than the T / M oil temperature (Ttm) a predetermined oil temperature (Ttm _{_1),} T / M unit loss As the oil temperature rises along with the time lapse is increased continuously . Thus, the amount of T / M unit loss due to the T / M oil temperature (Ttm) a predetermined oil temperature at a minimum value (Ttm _{_ 1).} This is because the T / M unit loss can be classified as friction loss and motor loss, and the friction loss is reduced when the oil temperature rises and the motor loss increases when the oil temperature rises. Therefore, the control unit 150, each of the switching control (the heat exchanger (105 T / M oil temperature of a predetermined fluid temperature on the (Ttm) (Ttm _{_ 1)} for use as a threshold valve (411, 421)) Heat exchange control at the < / RTI >

8 is a diagram showing a change in liquid temperature in a normal running state. The normal running state refers to a state in which the vehicle is moved by the power of the engine 1. [ As shown in Fig. 8, when the vehicle Ve is in the normal running state, the liquid temperature is a relationship of "T / M oil temperature Ttm <ENG oil temperature Toil <ENG cooling water temperature Thw". Also, ENG cooling (hereinafter referred to as "ENG fuel control") water temperature (Thw) is a predetermined water temperature (Thw _{_1)} for the fuel control to increase when the engine 1 is more than all is performed. That is, the water temperature (Thw _{_ 1)} is a predetermined threshold. ENG Fuel economy control is a control performed to improve fuel economy. ENG fuel economy control is performed by, for example, a control for automatically stopping the engine 1 at the time of a temporary stop, an operation point (engine speed and engine torque) of the engine 1 on the optimum fuel efficiency line having the best efficiency And an EV drive control for permitting the EV drive in which the vehicle moves by the power of the motors 2, 3. Although not shown in Fig. 8, in the high load running state, the ENG oil temperature Toil is higher than the T / M oil temperature Ttm and the ENG cooling water temperature Thw. For example, after a long time (for example, several hours) of the normal running state shown in Fig. 8, the vehicle enters a high load running state. Here, an example of the normal running state includes an HV running of the vehicle by the power of the engine 1 and the motors 2 and 3, and an engine running of the vehicle by the power of the engine 1 alone do.

[7. Heat Exchange Control] Fig. 9 is a flowchart showing an example of heat exchange control. The control routine shown in Fig. 9 is performed by the control unit 150. Fig.

9, the control unit 150 determines whether or not lower than a T / M oil temperature (Ttm) a predetermined oil temperature (Ttm _{_1)} (step S1). The predetermined oil temperature (Ttm _{_1)} is a preset threshold value.

If the T / M oil temperature (Ttm) a positive judgment is made at step (S1) by pre lower than the predetermined oil temperature (Ttm _{_1)} (step (S1): YES), the control unit 150 is a T / M five days The warming control for controlling the heat exchange state in the heat exchanger 105 is performed to warm it (step S2). In this case, the control unit 150 determines whether the water temperature is higher than (Thw _{_1)} ENG cooling water temperature (Thw) is determined in advance (step (S3)). Predetermined temperature (Thw _{_ 1)} is a preset threshold value.

If ENG cooling water temperature (Thw) is a positive determination in step (S3) by online higher than the determined temperature (Thw _{_1)} (step (S3): YES), the control unit 150 the first switch valve 411 ON to control the second switching valve 421 to be ON (step S4). During the execution of step S4, the first switching valve 411 and the second switching valve 421 are opened, heat exchange is performed between the T / M oil and the ENG cooling water, and the T / M oil and the ENG oil Heat exchange is performed. After the execution of step S4, the control unit 150 ends the control routine.

8, the ENG cooling water temperature Thw and the ENG oil temperature Toil are set so that the ENG cooling water temperature Thw and the ENG oil temperature &lt; RTI ID = 0.0 &gt; Toil) is higher than the T / M oil temperature (Ttm). Then, in step S4, the heat of the ENG cooling water and the ENG oil is transferred to the T / M oil to warm the T / M oil. As a result, the heat of the ENG cooling water and the heat of the ENG oil can warm the T / M oil prematurely. Thereby, the lubricant-requiring portion 30 can be warmed up early by the T / M oil passed through the heat exchanger 105.

ENG cooling water temperature when the (Thw) a negative determination in the step (S3) by a predetermined temperature (Thw _{_1)} or less (step (S3): No), the control unit 150 T / M oil temperature (Ttm) is ENG oil temperature Toil (step S5).

When the determination in step S5 is affirmative (step S5: YES), the control unit 150 determines that the first switching valve 411 is in the ON state, if the T / M oil temperature Ttm is lower than the ENG oil temperature Toil. And turns the second switch valve 421 ON (step S6). After the execution of step S6, the second switching valve 421 is opened and heat exchange is performed between the T / M oil and the ENG oil, but the first switching valve 411 is closed, And the ENG cooling water. After the execution of step S6, the control unit 150 ends the control routine.

As described above, when the step S6 is performed after the determination in the step S5, the T / M oil temperature Ttm is a state in which the T / M oil temperature Ttm is lower than the ENG oil temperature Toil, At the exchanger 105, the heat of the ENG oil is transferred to the T / M oil to warm the T / M oil. Therefore, the heat of the ENG oil can cause the T / M oil to warm up early. Thereby, the lubricant-requiring portion 30 can be warmed up early by the T / M oil passed through the heat exchanger 105. In addition, up to when the step (S6) is performed after the determination in step (S5), ENG coolant T / M does not give heat to the oil, thus ENG cooling water temperature (Thw) is a predetermined water temperature (Thw _{_ 1)} The ENG cooling water will warm up preferentially until it rises. Thereby, the engine 1 is warmed by the ENG cooling water.

If the determination at step S5 is negative (step S5: NO) because the T / M oil temperature Ttm is equal to or greater than the ENG oil temperature Toil, the control unit 150 determines whether the first switching valve 411 and / The second switch valve 421 is controlled to be OFF (step S7). During the execution of step S7, the first switching valve 411 and the second switching valve 421 are closed and thus the heat exchange between the T / M oil and the ENG cooling water and also between the T / M oil and the ENG oil Is not performed. That is, T / M oil does not receive heat from ENG cooling water and ENG oil. After the execution of step S7, the control unit 150 ends the control routine.

As described above, when step S7 is performed after the determination in step S5, the T / M oil temperature Ttm is a state in which the T / M oil temperature Ttm is higher than the ENG oil temperature Toil , So that the heat of the T / M oil is transferred to the ENG oil can be prevented by closing the second switching valve 421. Thereby, when the T / M oil is warmed, the heat of the T / M oil can be prevented from being lost to the ENG oil. Therefore, the lubricant-requiring portion 30 can be warmed early by the T / M oil passed through the heat exchanger 105. [

If the other hand, T / M oil temperature (Ttm) a negative determination in the step (S1) by more than a predetermined oil temperature (Ttm_ ₁₎ (step (S1): No), the control unit 150 T / M five days To control the heat exchange state in the heat exchanger 105 (step S8). In this case, the control unit 150 determines whether or not the ENG oil temperature Toil is lower than the ENG cooling water temperature Thw (step S9).

If the determination in step S9 is YES because the ENG oil temperature Toil is lower than the ENG cooling water temperature Thw (step S9: Yes), the control unit 150 determines that the T / M oil temperature Ttm ENG oil temperature Toil (step S10).

If the determination in step S10 is affirmative (step S10: YES) because the T / M oil temperature Ttm is lower than the ENG oil temperature Toil, the control unit 150 performs the above-described step S7 The first switch valve 411 and the second switch valve 421 are controlled to be OFF.

As described above, when the step S7 is performed after the determination in the step S10, the T / M oil temperature Ttm is set so that the T / M oil temperature Ttm is lower than the ENG cooling water temperature Thw and the ENG oil temperature Tg And the heat of the ENG oil is transferred to the T / M oil because the heat of the ENG cooling water moves to the T / M oil and the heat of the ENG oil to the T / M oil is lower than the temperature of the first switching valve 411 and the second switching valve 421, respectively. Thus, when the T / M oil is cooled, the T / M oil is prevented from being warmed by the ENG cooling water and the ENG oil, so that the cooling performance of the T / M oil can be ensured.

If the determination at step S10 is negative (step S10: NO) because the T / M oil temperature Ttm is equal to or greater than the ENG oil temperature Toil, the control unit 150 performs the above-described step S6 The first switch valve 411 is turned OFF and the second switch valve 421 is turned ON.

As described above, when step S6 is performed after the determination in step S10, the T / M oil temperature Ttm is a state in which the T / M oil temperature Ttm is higher than the ENG oil temperature Toil The heat of the ENG cooling water can be prevented from moving to the T / M oil by closing the first switching valve 411, and the heat of the T / M oil can be prevented by opening the second switching valve 421. [ Can be moved to the ENG oil. Thereby, when the T / M oil is cooled, the T / M oil is prevented from being warmed by the ENG cooling water, and the T / M oil is cooled by the ENG oil, so that the cooling property of the T / M oil can be ensured.

The control unit 150 determines that the T / M oil temperature Ttm is equal to or greater than the ENG oil temperature Tg (step S9) because the ENG oil temperature Toil is equal to or greater than the ENG cooling water temperature Thw It is determined whether or not it is lower than the cooling water temperature Thw (step S11).

If the determination in step S11 is affirmative (step S11: YES) because the T / M oil temperature Ttm is lower than the ENG cooling water temperature Thw, the control unit 150 performs the above-described step S7 To control the first switching valve 411 and the second switching valve 421 to be OFF.

As described above, when the step S7 is performed after the determination in the step S11, the "T / M oil temperature Ttm <ENG cooling water temperature Thw" ENG oil temperature Toil) &quot; is established. Therefore, by closing the first switching valve 411 and the second switching valve 421, the heat of the ENG cooling water is transferred to the T / M oil and the heat of the ENG oil is transferred to the T / M oil Can be prevented. Thus, when the T / M oil is cooled, the T / M oil is prevented from being warmed by the ENG cooling water and the ENG oil, so that the cooling performance of the T / M oil can be ensured.

If the negative determination is made in step S11 because the T / M oil temperature Ttm is equal to or greater than the ENG cooling water temperature Thw (step S11: NO), the control unit 150 sets the first switch valve 411 ON "to control the second switching valve 421 to be OFF (step S12). At the time of performing the step S12, the first switching valve 411 is opened, the heat exchange is performed between the T / M oil and the ENG cooling water, but the second switching valve 421 is closed, And ENG oil is not performed. After the execution of step S12, the control unit 150 ends the control routine.

As described above, when the negative determination is made in step S11, the T / M oil temperature Ttm is in a state where the T / M oil temperature Ttm is higher than the ENG cooling water temperature Thw, 411), the heat of the T / M oil can be transferred to the ENG cooling water, and the heat of the ENG oil can be prevented from moving to the T / M oil by closing the second switching valve 421 have. As a result, when the T / M oil is cooled, the T / M oil is cooled by heat radiation to the ENG cooling water, and the T / M oil is prevented from being warmed by the ENG oil, .

[8. Comparison with Reference Example Here, to explain the advantages of the cooling system 100 according to the second embodiment, referring to Fig. 11, the cooling system 100 and the reference example will be compared. Here, for the cooling system 500 shown in FIG. 11, a description of components similar to the cooling system 300 shown in FIG. 10 described above will be omitted, and the reference numerals used for the cooling system 300 Is used.

11 is a schematic diagram showing a schematic configuration of a cooling system 500 according to a reference example. As shown in Fig. 11, the cooling system 500 according to the reference example does not have the heat exchanger 105 described above. That is, in the cooling system 500, heat exchange is not performed between the T / M oil and the liquid on the engine 1 side (ENG cooling water in the ENG cooling circuit 410 or ENG oil in the ENG oil circuit 420) . Therefore, in the cooling system 500, when the lubrication-requiring portion 30 is warmed, the T / M oil can not be warmed by the liquid (ENG cooling water or ENG oil) on the engine 1 side, A delay in the temperature rise of the oil occurs. Therefore, in the normal running state, the agitation loss and dragging loss caused by the lubrication-requiring portion 30 can be large. Further, in a high load running state, the cooling property of the T / M oil is lowered, whereby the loss (copper loss and iron loss) of the motor component can be increased.

The advantages of the second embodiment include warming performance and fuel economy in addition to advantages (cooling performance and structure) similar to the first embodiment described above. According to the second embodiment, heat exchange is performed between the liquid (ENG cooling water or ENG oil) on the engine 1 side and the T / M oil at the time of warming, so that the rise of the T / M oil temperature Ttm is accelerated , Warm-up can be completed early. Thus, the agitation loss and the dragging loss (T / M friction) in the lubrication-requiring portion 30 are reduced, and the fuel consumption can be improved.

Further, by performing the switching control in consideration of the ENG cooling water temperature Thw, the adverse influence on the friction in the engine 1 (hereinafter referred to as " ENG friction ") and the ENG fuel economy control can be minimized. Also, when comparing the oil temperature sensitivity of the ENG friction to the ENG oil and the oil temperature sensitivity of the T / M friction to the T / M oil, the oil temperature sensitivity of the T / M friction is greater than the oil temperature sensitivity of the ENG friction. Therefore, when the ENG oil temperature (Toil) is in the state of the ENG oil temperature (Toil) higher than the T / M oil temperature (Ttm), moving the ENG oil heat to the T / M oil reduces the T / M friction , Fuel economy can be improved. Here, the ENG friction is reduced as the ENG oil temperature (Toil) rises.

As described above, the reduction of the pressure loss caused by the T / M oil and the expansion of the operating limit oil temperature range of the electric oil pump 102 ensure a sufficient flow rate of the T / M oil Thereby improving the degree of freedom of the electric oil pump. Thereby, the oil circulation circuit 200 having the circuit configuration in which the inverter circuit and the transaxle flow path are integrated can be provided.

As described above, according to the second embodiment, in addition to the effect provided by the above-described first embodiment, the T / M oil can be warmed early and the warming of the power transmitting mechanism is completed early, The T / M friction can be reduced and the fuel consumption can be improved.

It should be noted that the vehicle cooling system according to the present invention is not limited to the second embodiment described above, and any changes can be made without departing from the object of the present invention.

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

Further, the first oil temperature sensor 151 may be installed on the upstream side of the heat exchanger 105 in the lubrication circuit 220. For example, the first oil temperature sensor 151 can detect the temperature Ttm of the T / M oil stored in the oil reservoir 104 installed in the oil reservoir 104. [ Likewise, the installation position of the water temperature sensor 152 is not particularly limited as long as the installation position is on the upstream side of the heat exchanger 105 in the ENG cooling circuit 410. The mounting position of the second oil temperature sensor 153 is not particularly limited as long as the mounting position is on the upstream side of the heat exchanger 105 in the ENG oil circuit 420. [

Claims (13)

An automotive cooling system mounted on a vehicle having an electric motor, an inverter (21) electrically connected to the electric motor, and a power transmission mechanism (5) for transmitting the power output from the electric motor to the wheel (4) The vehicle cooling system includes:
And an oil circulation circuit (200), wherein the oil circulation circuit
The oil reservoir 104,
A first circuit (210) having a first oil pump (102) and an oil cooler (103), wherein the first oil pump draws in the oil stored in the oil reservoir (104) The oil cooler is installed between the first oil pump 102 and the inverter 21 or the electric motor and the oil cooler 103 is connected to the inverter 21 And the oil supplied to the electric motor is cooled and all the oil from the oil cooler 103 is returned to the oil reservoir 104 directly without passing through the lubricating- 1 circuit, and
The second circuit (220) has a second oil pump (101), and the second oil pump sucks the oil stored in the oil reservoir (104) and supplies the oil to the power transmission mechanism Which is supplied to the lubrication-requiring portion included in the second circuit (5)
And the cooling system. The method according to claim 1,
In the first circuit 210, the inverter 21 and the electric motor are installed on the downstream side of the first oil pump 102, the inverter 21 and the electric motor are connected in series, and the electric motor is connected to the inverter 21 ) Of the vehicle. The method according to claim 1,
In the first circuit, the inverter (21) and the electric motor are installed on the downstream side of the first oil pump (102), and the inverter (21) and the electric motor are connected in parallel. 4. The method according to any one of claims 1 to 3,
Wherein the electric motor has a stator and a rotor, and in the first circuit, the electric motor cooling pipe for supplying oil to the electric motor has a discharge hole for discharging oil toward the stator. 4. The method according to any one of claims 1 to 3,
Wherein the oil flowing in the first circuit has insulation. 4. The method according to any one of claims 1 to 3,
Wherein the inverter (21) is configured so that oil discharged from the first oil pump (102) flows as refrigerant in the interior. 4. The method according to any one of claims 1 to 3,
Wherein the oil cooler (103) is an air cooling type oil cooler that performs heat exchange between oil and air. 4. The method according to any one of claims 1 to 3,
Wherein the vehicle cooling system is mounted on a vehicle having an electric motor and an engine as a power source,
The first oil pump 102 is an electric oil pump driven by an electric motor,
Wherein the second oil pump (101) is a mechanical oil pump driven by an engine. 9. The method of claim 8,
The second circuit 220 is capable of heat exchange between the oil discharged from the second oil pump 101 and the engine cooling water and heat exchange between the oil discharged from the second oil pump 101 and the engine oil Further comprising a three-phase heat exchanger (105) configured. 10. The method of claim 9,
The first switching valve (411) is disposed in a circuit through which the engine cooling water circulates. The first switching valve is a switching valve that is switched between an open state in which engine cooling water can flow through the heat exchanger and an engine cooling water A first switching valve, which is switched between a closed state and a closed state,
The second switching valve 421 is installed in a circuit through which the engine oil circulates. The second switching valve is an open state in which engine oil can flow through the heat exchanger and an open state in which the engine oil can not flow through the heat exchanger Wherein the second switching valve is switched between a closed state and a closed state. 11. The method of claim 10,
A first oil temperature sensor 151 for detecting the temperature of the oil,
A water temperature sensor 152 for detecting the temperature of the engine cooling water,
A second oil temperature sensor 153 for detecting the temperature of the engine oil, and
Based on the temperature of the oil detected by the first oil temperature sensor 151, the temperature of the engine cooling water detected by the water temperature sensor, and the temperature of the engine oil detected by the second oil temperature sensor 153 , A control unit (150) configured to control opening and closing of the first switching valve (411) and the second switching valve (421), respectively,
The control unit 150 controls at least the second switch valve 421 of the first switch valve 411 and the second switch valve 421 to be in an open state when the temperature of the oil is lower than a predetermined oil temperature And to perform warming control to increase the temperature of the oil through heat exchange in the heat exchanger. 12. The method of claim 11,
When the control unit 150 performs the warming control, the control unit 150 controls the first switching valve 411 and the second switching valve 421 to be in the open state when the temperature of the engine cooling water is higher than the predetermined water temperature Wherein the cooling system is configured to control the cooling system. 12. The method of claim 11,
When the control unit 150 performs the warming control, when the temperature of the engine coolant is below the predetermined water temperature and the temperature of the oil is lower than the temperature of the engine oil, the control unit 150 sets the first switch valve 411 to the closed state , And to control the second switching valve (421) to be in the open state.

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