Vehicle cooling system

Abstract

To provide a vehicle cooling system capable of enhancing an increase in a temperature of a transmission when a temperature of transmission oil is increased and enhancing a decrease in the temperature of the transmission when the temperature of the transmission oil is decreased.SOLUTION: A vehicle cooling system comprises: an exit side cooling water supply passage 24 which branches from a feed passage 21A; an entrance side cooling water supply passage 25 which branches from a position close to an upstream side of a cooling water inlet 2A in a return passage 21B; and a flow passage switch valve 41 which can switch between the exit side cooling water supply passage 24 and the entrance side cooling water supply passage 25 so as to allow cooling water either therein to flow into an oil cooler 4A. A control section 10 controls the flow passage switch valve 41 on the basis of comparison results between a temperature of the cooling water and a predetermined water temperature TWc and between a temperature of transmission oil and a predetermined oil temperature TOc.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cooling system for a vehicle. [Background technology]

[0002] Patent Document 1 describes a power output device having a heat exchanger that can exchange heat between engine coolant and transmission oil. In this power output device, the heat exchange between the engine coolant and transmission oil in the heat exchanger can be switched on and off depending on the temperature of the transmission oil. This allows the power output device described in Patent Document 1 to set the temperature of the transmission oil, which is used to regulate the temperature of the electric motor, to an appropriate temperature depending on the situation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-162132 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in Patent Document 1 simply switches between performing and stopping heat exchange in the heat exchanger when cooling the transmission oil and when heating the transmission oil, and since the temperature control performance of the transmission oil is affected by the temperature of the cooling water passing through the heat exchanger, it is not possible to promote the heating and cooling of the transmission oil.

[0005] The present invention has been made in response to the above-mentioned problems, and aims to provide a vehicle cooling system that can accelerate the temperature rise of the transmission when the temperature of the transmission oil is raised, and can accelerate the temperature drop of the transmission when the temperature of the transmission oil is lowered. [Means for solving the problem]

[0006] The present invention relates to an engine through which cooling water flows, a transmission through which transmission oil flows, and a cooling water supply system connected to a cooling water outlet of the engine via a feed passage and connected to a cooling water inlet of the engine via a return passage. The aforementioned a radiator that cools the cooling water by heat exchange and causes the cooling water to flow into the return passage; The aforementioned and an oil cooler for exchanging heat with cooling water, wherein the cooling water flows out of the cooling water outlet and branches off from the feed passage. The aforementioned an outlet-side cooling water supply path that supplies a portion of the cooling water to the oil cooler; and a cooling water return path that branches off from a position in the vicinity of the upstream side of the cooling water inlet and leads to the cooling water inlet. The aforementioned an inlet-side cooling water supply path that supplies a portion of the cooling water to the oil cooler; and a cooling water supply path that flows through the outlet-side cooling water supply path. The aforementioned The cooling water flows through the inlet side cooling water supply path. The aforementioned a flow path switching valve that can switch so that either the cooling water or the transmission oil flows into the oil cooler; and a control unit that controls the flow path switching valve based on a comparison result between the cooling water temperature and a predetermined water temperature and a comparison result between the oil temperature of the transmission oil and the predetermined oil temperature. When the cooling water temperature is lower than the predetermined water temperature and the oil temperature is lower than the predetermined oil temperature, the control unit controls the flow path switching valve to block the cooling water flowing through the inlet side cooling water supply path and the outlet side cooling water supply path so that the cooling water flowing through the inlet side cooling water supply path and the cooling water flowing through the outlet side cooling water supply path do not flow into the oil cooler; when the cooling water temperature is equal to or higher than the predetermined water temperature and the oil temperature is lower than the predetermined oil temperature, the control unit controls the flow path switching valve to block the cooling water flowing through the inlet side cooling water supply path so that the cooling water flowing through the outlet side cooling water supply path flows into the oil cooler; and when the oil temperature is equal to or higher than the predetermined oil temperature, regardless of whether the cooling water temperature is lower than the predetermined water temperature or equal to or higher than the predetermined water temperature, the control unit controls the flow path switching valve to block the cooling water flowing through the outlet side cooling water supply path so that the cooling water flowing through the inlet side cooling water supply path flows into the oil cooler. It is characterized by: [Effects of the Invention]

[0007] As described above, according to the present invention, a vehicle cooling system can be provided that can promote the temperature increase of the transmission when the temperature of the transmission oil is increased, and can promote the temperature decrease of the transmission when the temperature of the transmission oil is decreased. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the configuration of a vehicle equipped with a vehicle cooling system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the flow of coolant in the first state of the cooling system for a vehicle according to one embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing the flow of coolant in the second state of the cooling system for a vehicle according to one embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the flow of coolant in the cooling system for a vehicle according to one embodiment of the present invention in a third state. [Figure 5] FIG. 5 is a diagram showing the control state of the flow path switching valve with respect to the coolant temperature and oil temperature in the cooling system for a vehicle according to one embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing temperature ranges and thresholds of the coolant temperature and oil temperature in a cooling system for a vehicle according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] a control unit that controls the flow path switching valve based on a comparison result between the coolant temperature of the coolant and a predetermined water temperature and a comparison result between the oil temperature of the transmission oil and the coolant. The cooling system for a vehicle according to one embodiment of the present invention includes an engine through which coolant flows, a transmission through which transmission oil flows, a radiator connected to the engine's coolant outlet via a feed passage and to the engine's coolant inlet via a return passage, and configured to cool the coolant flowing in from the feed passage by heat exchange and discharge the cooled coolant into the return passage, and an oil cooler that performs heat exchange between the transmission oil and the coolant. The cooling system is characterized by including: an outlet-side coolant supply path that branches off from the feed passage and supplies a portion of the coolant flowing out from the coolant outlet to the oil cooler; an inlet-side coolant supply path that branches off at a position in the return passage near the upstream side of the coolant inlet and supplies a portion of the coolant heading toward the coolant inlet to the oil cooler; As a result, the vehicle cooling system according to one embodiment of the present invention can promote the temperature increase of the transmission when the temperature of the transmission oil is increased, and can promote the temperature decrease of the transmission when the temperature of the transmission oil is decreased. [Example]

[0010] A vehicle cooling system according to an embodiment of the present invention will now be described with reference to the drawings. Figures 1 to 6 are diagrams showing a vehicle cooling system according to an embodiment of the present invention.

[0011] First, the configuration will be described. As shown in Fig. 1, a vehicle 1 includes an engine (referred to as ENG in the figure) 2, a transmission (referred to as T / M in the figure) 3, an electric motor (referred to as MGU in the figure) 4, and an inverter (referred to as INV in the figure) 5.

[0012] The engine 2 is an internal combustion engine that uses gasoline or diesel fuel and generates driving force (engine torque) for traveling. A water jacket (not shown) through which cooling water flows is provided inside the engine 2. The engine 2 has a cooling water inlet 2A through which the cooling water flows in and a cooling water outlet 2B through which the cooling water flows out.

[0013] The transmission 3 is connected to the engine 2 and transmits the driving force (engine torque) generated by the engine 2. The transmission 3 is equipped with a speed change mechanism (not shown), and changes the speed of the rotation transmitted from the engine 2 by the speed change mechanism and transmits it to drive wheels (not shown).

[0014] The electric motor 4 is electrically connected to a battery (not shown) via an inverter 5. The electric motor 4 is built into a portion of the transmission 3 following the speed change mechanism. The driving force (electric motor torque) for running generated by the electric motor 4 is transmitted to the drive wheels without passing through the speed change mechanism of the transmission 3. Transmission oil flows inside the transmission 3 and the electric motor 4.

[0015] The electric motor 4 is provided with an oil cooler (denoted as O / C in the drawing) 4A, which raises or lowers the temperature of transmission oil by heat exchange with cooling water.

[0016] The inverter 5 converts DC power from a battery (not shown) into AC power and supplies it to the electric motor 4, and also converts AC power generated by the electric motor 4 into DC power and supplies it to the battery.

[0017] The vehicle 1 is equipped with one radiator 50. The radiator 50 cools the coolant by heat exchange with the airflow while the vehicle is running. The radiator 50 is equipped with a high-temperature section 50H that cools the relatively high-temperature coolant that has cooled the engine 2, and a low-temperature section 50L that cools the relatively low-temperature coolant that has cooled the inverter 5.

[0018] The high temperature section 50H has an inlet 51A through which the cooling water flows in from the engine 2 and an outlet 52A through which the cooled cooling water flows out. The low temperature section 50L has an inlet 51B through which the cooling water flows in from the inverter 5 and an outlet 52B through which the cooled cooling water flows out.

[0019] The vehicle 1 is equipped with an engine coolant circulation circuit 21. The engine coolant circulation circuit 21 connects the engine 2 and a radiator 50, and circulates coolant between the engine 2 and the radiator 50. The radiator 50 cools the coolant circulating through the engine coolant circulation circuit 21.

[0020] The engine coolant circulation circuit 21 includes a feed passage 21A that feeds coolant from the engine 2 to the high-temperature portion 50H of the radiator 50, and the feed passage 21A is connected to a coolant outlet 2B of the engine 2 and an inlet 51A of the radiator 50.

[0021] The engine coolant circulation circuit 21 includes a return passage 21B that returns the coolant cooled by the radiator 50 to the engine 2, and the return passage 21B is connected to an outlet 52A of the radiator 50 and a coolant inlet 2A of the engine 2.

[0022] In this way, the radiator 50 is connected to the coolant outlet 2B of the engine 2 via the feed passage 21A, and is connected to the coolant inlet 2A of the engine 2 via the return passage 21B. The radiator 50 cools the coolant flowing in from the feed passage 21A through heat exchange and causes it to flow out into the return passage 21B.

[0023] Vehicle 1 is equipped with a mechanical water pump (denoted as WP in the drawing) 32 that operates using engine 2 as a driving force source. Water pump 32 is provided in return passage 21B near coolant inlet 2A of engine 2, and sends coolant drawn from return passage 21B to engine 2. A pulley (not shown) of water pump 32 is connected to a crank pulley (not shown) of engine 2 via a fan belt (not shown), and water pump 32 forcibly circulates the coolant using power obtained from the rotation of engine 2.

[0024] The vehicle 1 is equipped with a thermostat 33. The thermostat 33 is provided in the return passage 21B near the upstream side of the water pump 32. The thermostat 33 closes its valve when the coolant temperature is lower than a predetermined temperature, thereby preventing the coolant from circulating in the engine coolant circulation circuit 21. The thermostat 33 opens its valve when the coolant temperature exceeds the predetermined temperature, thereby allowing the coolant to circulate in the engine coolant circulation circuit 21. That is, when the thermostat 33 is open, the coolant in the return passage 21B is sent to the engine 2 by the water pump 32. The coolant sent to the engine 2 by the water pump 32 cools the engine 2, is discharged from the engine 2, and is introduced into the radiator 50 through the feed passage 21A. The coolant cooled in the radiator 50 is then returned to the engine 2 through the return passage 21B.

[0025] The vehicle 1 is equipped with a high-temperature coolant circulation circuit 22. Coolant that at least cools the engine 2 circulates through the high-temperature coolant circulation circuit 22. A heater core 31 and an EGR cooler 30 are connected to the engine 2 via the high-temperature coolant circulation circuit 22.

[0026] The heater core 31 heats the vehicle interior (not shown) by exchanging heat with high-temperature coolant introduced from the engine 2. The EGR cooler 30 cools the exhaust gas discharged from the engine 2 by exchanging heat with the coolant. The exhaust gas cooled by the EGR cooler 30 is sent to the intake path of the engine 2.

[0027] The high-temperature coolant circulation circuit 22 has a feed passage 22A that sends coolant from the engine 2 to the heater core 31, a feed passage 22B that sends coolant from the engine 2 to the EGR cooler 30, and a return passage 22C that returns the coolant from the heater core 31 and the EGR cooler 30 to the engine 2.

[0028] The return passage 22C is configured to allow the coolant from the heater core 31 and the coolant from the EGR cooler 30 to join together. The upstream ends of the feed passages 22A and 22B branch off from the feed passage 21A of the engine coolant circulation circuit 21. The downstream end of the return passage 22C is connected to a bypass passage within the thermostat 33. Therefore, while the engine 2 is operating, the coolant always circulates through the high-temperature coolant circulation circuit 22, regardless of whether the thermostat 33 is open or closed.

[0029] The vehicle 1 is equipped with a low-temperature coolant circulation circuit 23. Coolant that is lower in temperature than the coolant circulating through the high-temperature coolant circulation circuit 22 circulates through the low-temperature coolant circulation circuit 23. The inverter 5 is connected to a radiator 50 via the low-temperature coolant circulation circuit 23. The radiator 50 cools the coolant circulating through the low-temperature coolant circulation circuit 23.

[0030] The low-temperature cooling water circulation circuit 23 has a feed passage 23A that sends cooling water from the inverter 5 to the radiator 50, and a return passage 23B that returns cooling water from the radiator 50 to the inverter 5. An electrically operated electric water pump (referred to as EWP in the drawing) 37 is provided in the return passage 23B. The cooling water circulating through the low-temperature cooling water circulation circuit 23 cools the inverter 5.

[0031] Therefore, the low-temperature coolant circulation circuit 23 circulates the coolant between the inverter 5 and the radiator 50. The coolant circulating through the low-temperature coolant circulation circuit 23 has a lower temperature than the coolant circulating through the high-temperature coolant circulation circuit 22.

[0032] The vehicle 1 includes a control unit 10. The control unit 10 is configured as an ECU (Electronic Control Unit) that is made up of a computer unit that includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory that stores backup data, etc., an input port, and an output port.

[0033] The ROM of the control unit 10 stores various constants, maps, etc., as well as programs for causing the computer unit to function as the control unit 10. The control unit 10 achieves its intended operation by having the CPU execute the programs stored in the ROM using the RAM as a working area.

[0034] The control unit 10 switches the driving mode between an engine driving mode in which the vehicle runs using at least the engine 2 as a driving power source, and an EV driving mode in which the vehicle runs using the electric motor 4 as a driving power source without using the engine 2 as a driving power source. The engine driving mode includes a state in which the vehicle runs using the engine 2 as a driving power source, and a state in which the vehicle runs using both the engine 2 and the electric motor 4 as driving power sources.

[0035] In a vehicle 1 having a transmission 3 with a built-in electric motor 4, if the transmission 3 is cooled below the optimum temperature range due to the influence of the management temperature of the inverter 5 that drives the electric motor 4, the viscosity of the transmission oil increases, resulting in a deterioration in the transmission efficiency of the transmission 3. On the other hand, if the temperature of the transmission 3 rises above the optimum temperature range, the durability of the transmission 3 and the electric motor 4 therein deteriorates. In order to accelerate the increase and decrease in the temperature of the transmission oil, it is conceivable to configure the oil cooler 4A so that it can be switched between the high-temperature section 50H and the low-temperature section 50L of the radiator 50. However, because the high-temperature section 50H and the low-temperature section 50L of the radiator 50 are responsible for different temperature zones and have different cooling water pressures, such a switchover without being restricted by the temperature zones is technically difficult and results in a complex structure.

[0036] Therefore, in this embodiment, the vehicle 1 is equipped with an outlet side cooling water supply path 24, an inlet side cooling water supply path 25, and a flow path switching valve 41 so that the temperature rise and fall of the transmission oil can be promoted while maintaining the configuration in which the high temperature section 50H of the radiator 50 is used to cool the transmission 3.

[0037] The outlet-side cooling water supply path 24 branches off from the feed path 21A and supplies a portion of the cooling water flowing out from the cooling water outlet 2B to the oil cooler 4A.

[0038] The inlet-side cooling water supply path 25 branches off from the return passage 21B at a position near the upstream side of the cooling water inlet 2A, and supplies a portion of the cooling water heading toward the cooling water inlet 2A to the oil cooler 4A.

[0039] The flow path switching valve 41 switches the supply state of cooling water to the oil cooler 4A under the control of the control unit 10. The flow path switching valve 41 is configured to be able to switch so that either the cooling water flowing through the outlet-side cooling water supply path 24 or the cooling water flowing through the inlet-side cooling water supply path 25 flows into the oil cooler 4A.

[0040] In this embodiment, the feed passage 21A and the flow path switching valve 41 are connected by an outlet-side cooling water supply passage 24. Furthermore, the return passage 21B and the flow path switching valve 41 are connected by an inlet-side cooling water supply passage 25. The flow path switching valve 41 is connected to a cooling water introduction passage 45 of the oil cooler 4A. The cooling water discharge passage 26 of the oil cooler 4A is connected to the return passage 22C. The cooling water that has cooled the oil cooler 4A flows through the cooling water discharge passage 26 and flows out into the return passage 22C.

[0041] The control unit 10 controls the flow path switching valve 41 based on the comparison result between the coolant temperature of the coolant and a predetermined water temperature TWc and the comparison result between the oil temperature of the transmission oil and a predetermined oil temperature TOc.

[0042] The flow path switching valve 41 is configured to be switchable between a first state (see Figure 2) in which the cooling water flowing through the inlet side cooling water supply path 25 and the cooling water flowing through the outlet side cooling water supply path 24 are blocked, so that the cooling water flowing through the inlet side cooling water supply path 25 and the cooling water flowing through the outlet side cooling water supply path 24 do not flow into the oil cooler 4A; a second state (see Figure 3) in which the cooling water flowing through the inlet side cooling water supply path 25 is blocked, so that the cooling water flowing through the outlet side cooling water supply path 24 flows into the oil cooler 4A; and a third state (see Figure 4) in which the cooling water flowing through the outlet side cooling water supply path 24 is blocked, so that the cooling water flowing through the inlet side cooling water supply path 25 flows into the oil cooler 4A.

[0043] 2, when the flow path switching valve 41 is in the first state, communication between the outlet-side cooling water supply path 24 and the cooling water introduction path 45 of the oil cooler 4A is blocked, and communication between the inlet-side cooling water supply path 25 and the cooling water introduction path 45 of the oil cooler 4A is blocked. Therefore, the cooling water flowing through the inlet-side cooling water supply path 25 and the cooling water flowing through the outlet-side cooling water supply path 24 does not flow into the oil cooler 4A.

[0044] 3, when the flow path switching valve 41 is in the second state, the outlet-side cooling water supply path 24 communicates with the cooling water introduction path 45 of the oil cooler 4A via the flow path switching valve 41. Therefore, a portion of the cooling water that flows out from the cooling water outlet 2B to the feed path 21A passes through the outlet-side cooling water supply path 24 and is supplied to the oil cooler 4A.

[0045] 4, when the flow path switching valve 41 is in the third state, the inlet-side cooling water supply path 25 communicates with the cooling water introduction path 45 of the oil cooler 4A via the flow path switching valve 41. Therefore, part of the cooling water flowing through the return path 21B toward the cooling water inlet 2A is supplied to the oil cooler 4A through the inlet-side cooling water supply path 25.

[0046] Fig. 5 shows the control state of the flow path switching valve with respect to the coolant temperature and oil temperature. In Fig. 5, the predetermined water temperature TWc is a threshold value related to the engine water temperature, and is the lower limit water temperature at which waste heat from the engine 2 may be used to warm up the transmission 3. The predetermined oil temperature TOc is the lower limit oil temperature at which transmission oil needs to be cooled to protect the electric motor 4 and the components of the transmission 3.

[0047] 5, when the coolant temperature (referred to as engine water temperature in the figure) is lower than a predetermined water temperature TWc and the oil temperature (referred to as transmission oil temperature in the figure) is lower than a predetermined oil temperature TOc, the control unit 10 switches the flow path switching valve 41 to the first state. When the coolant temperature is equal to or higher than the predetermined water temperature TWc and the oil temperature is lower than a predetermined oil temperature TOc, the control unit 10 switches the flow path switching valve 41 to the second state. When the oil temperature is equal to or higher than the predetermined oil temperature TOc, the control unit 10 switches the flow path switching valve 41 to the third state.

[0048] In Fig. 6, the vertical axis represents temperature, and the horizontal axis represents the location where the temperature is measured. In detail, Fig. 6 shows the coolant temperature (referred to as engine water temperature) at the coolant inlet 2A (referred to as engine inlet in the figure) and the coolant outlet 2B (referred to as engine outlet in the figure) of the engine 2, and the oil temperature of the transmission oil (referred to as transmission oil temperature in the figure).

[0049] 6, the temperature range of the coolant temperature at the coolant outlet 2B is higher than the temperature range of the coolant temperature at the coolant inlet 2A due to the temperature rise inside the engine 2. In addition, the temperature range of the transmission oil temperature is wider than the temperature range of the coolant temperature of the engine 2. The maximum allowable oil temperature and the predetermined oil temperature TOc of the transmission oil are set higher than the maximum allowable coolant temperature at the coolant outlet 2B.

[0050] For example, when the transmission oil temperature is at the maximum allowable temperature, the flow path switching valve 41 is switched to the third state because the oil temperature is equal to or higher than the predetermined oil temperature TOc. Therefore, a portion of the coolant flowing through the return passage 21B toward the coolant inlet 2A is supplied to the oil cooler 4A through the inlet-side coolant supply path 25. The temperature difference between the oil temperature and the coolant temperature in the oil cooler 4A is ΔT2 when the coolant is supplied from the coolant inlet 2A to the oil cooler 4A, which is greater than the temperature difference ΔT1 when the coolant is supplied from the coolant outlet 2B to the oil cooler 4A. Therefore, the transmission 3 can be cooled using coolant at a lower temperature. This facilitates the cooling of the transmission 3.

[0051] On the other hand, when the coolant temperature is equal to or higher than the predetermined water temperature TWc and the oil temperature is lower than the predetermined oil temperature TOc, the flow path switching valve 41 is switched to the second state. As a result, part of the coolant flowing out from the coolant outlet 2B to the feed passage 21A is supplied to the oil cooler 4A through the outlet-side coolant supply path 24. In this case, the coolant temperature at the coolant outlet 2B is higher than the coolant temperature near the coolant inlet 2A, which can promote a temperature rise in the transmission 3.

[0052] As described above, the vehicle cooling system of this embodiment includes the outlet-side cooling water supply path 24 that branches off from the feed path 21A and supplies a portion of the cooling water flowing out from the cooling water outlet 2B to the oil cooler 4A, the inlet-side cooling water supply path 25 that branches off from the return path 21B at a position upstream of the cooling water inlet 2A and supplies a portion of the cooling water heading toward the cooling water inlet 2A to the oil cooler 4A, and the flow path switching valve 41 that can switch either the cooling water flowing through the outlet-side cooling water supply path 24 or the cooling water flowing through the inlet-side cooling water supply path 25 so that it flows into the oil cooler 4A. The control unit 10 controls the flow path switching valve 41 based on the results of comparing the cooling water temperature of the cooling water with the predetermined water temperature TWc and the results of comparing the oil temperature of the transmission oil with the predetermined oil temperature TOc.

[0053] As a result, when the temperature of the transmission oil is to be increased, the increase in temperature of the transmission oil can be accelerated by switching the flow path switching valve 41 so that high-temperature cooling water flowing through the outlet-side cooling water supply path 24 flows into the oil cooler 4A. When the temperature of the transmission oil is to be decreased, the decrease in temperature of the transmission oil can be accelerated by switching the flow path switching valve 41 so that low-temperature cooling water flowing through the inlet-side cooling water supply path 25 flows into the oil cooler 4A.

[0054] As a result, when the temperature of the transmission oil is increased, the temperature increase of the transmission 3 can be accelerated, and when the temperature of the transmission oil is decreased, the temperature decrease of the transmission 3 can be accelerated.

[0055] In addition, in the vehicle cooling system of this embodiment, when the coolant temperature is equal to or higher than a predetermined water temperature TWc and the oil temperature is lower than a predetermined oil temperature TOc, the control unit 10 controls the flow path switching valve 41 to block the coolant flowing through the inlet side coolant supply path 25 and allow the coolant flowing through the outlet side coolant supply path 24 to flow into the oil cooler 4A.

[0056] This allows relatively high-temperature cooling water flowing out from the cooling water outlet 2B of the engine 2 to be supplied to the oil cooler 4A, thereby facilitating the temperature rise of the transmission 3 and the transmission oil.

[0057] In addition, in the vehicle cooling system of this embodiment, when the oil temperature is equal to or higher than a predetermined oil temperature TOc, the control unit 10 controls the flow path switching valve 41 to block the cooling water flowing through the outlet side cooling water supply path 24 and allow the cooling water flowing through the inlet side cooling water supply path 25 to flow into the oil cooler 4A.

[0058] This allows relatively low-temperature cooling water flowing from the radiator 50 to the cooling water inlet 2A of the engine 2 to be supplied to the oil cooler 4A, facilitating a decrease in the temperature of the transmission 3 and the transmission oil.In addition, the temperature of the electric motor 4 and other components constituting the transmission 3 can be reduced to protect them.

[0059] In addition, in the vehicle cooling system of this embodiment, when the coolant temperature is below a predetermined water temperature TWc and the oil temperature is below a predetermined oil temperature TOc, the control unit 10 controls the flow path switching valve 41 to block the coolant flowing through the inlet side coolant supply path 25 and the coolant flowing through the outlet side coolant supply path 24, so that the coolant flowing through the inlet side coolant supply path 25 and the coolant flowing through the outlet side coolant supply path 24 do not flow into the oil cooler 4A.

[0060] As a result, the coolant is no longer cooled by the oil cooler 4A, and the temperature rise of the engine 2 can be promoted.

[0061] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0062] 1 vehicle 2 engines 2A cooling water inlet 2B Cooling water outlet 3 Transmission 4A Oil cooler 10 Control Unit 21 Engine cooling water circulation circuit 21A Delivery passage 21B Return passage 24 Outlet side cooling water supply path 25 Inlet cooling water supply path 41 Flow path switching valve 50 Radiator TOc specified oil temperature TWc's set water temperature

Claims

1. an engine through which cooling water flows; A transmission through which transmission oil flows; a radiator connected to a cooling water outlet of the engine via a feed passage and to a cooling water inlet of the engine via a return passage, for cooling the cooling water flowing in from the feed passage by heat exchange and discharging the cooled water into the return passage; an oil cooler that exchanges heat between the transmission oil and the cooling water, an outlet-side cooling water supply path that branches off from the feed passage and supplies a portion of the cooling water that has flowed out from the cooling water outlet to the oil cooler; an inlet-side cooling water supply path that branches off from the return passage at a position near the upstream side of the cooling water inlet and supplies a portion of the cooling water flowing toward the cooling water inlet to the oil cooler; a flow path switching valve that switches between the cooling water flowing through the outlet-side cooling water supply path and the cooling water flowing through the inlet-side cooling water supply path so that the cooling water flows into the oil cooler; a control unit that controls the flow path switching valve based on a comparison result between a cooling water temperature of the cooling water and a predetermined water temperature and a comparison result between an oil temperature of the transmission oil and a predetermined oil temperature, The control unit When the cooling water temperature is lower than the predetermined water temperature and the oil temperature is lower than the predetermined oil temperature, controlling the flow path switching valve to block the cooling water flowing through the inlet side cooling water supply path and the cooling water flowing through the outlet side cooling water supply path so that the cooling water flowing through the inlet side cooling water supply path and the cooling water flowing through the outlet side cooling water supply path do not flow into the oil cooler; When the cooling water temperature is equal to or higher than the predetermined water temperature and the oil temperature is lower than the predetermined oil temperature, controlling the flow path switching valve so that the cooling water flowing through the inlet side cooling water supply path is blocked and the cooling water flowing through the outlet side cooling water supply path flows into the oil cooler; When the oil temperature is equal to or higher than the predetermined oil temperature, regardless of whether the cooling water temperature is lower than the predetermined water temperature or equal to or higher than the predetermined water temperature, a cooling system for a vehicle, characterized in that the flow path switching valve is controlled to block the cooling water flowing through the outlet side cooling water supply path and to allow the cooling water flowing through the inlet side cooling water supply path to flow into the oil cooler.

2. A cooling system for a vehicle as described in Claim 1, characterized in that it is equipped with an electric motor through which the transmission oil, which has been heat exchanged with the cooling water by the oil cooler, circulates.

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