JP2016031111A - Oil temperature control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil temperature control device capable of promoting warming-up with warmed transmission oil and suppressing the excessive temperature rise while suppressing a cost increase.SOLUTION: An oil temperature control device 1 includes a first heat exchanger 4 for exchanging heat between engine oil 6 and T/M oil 8, a second heat exchanger 5 for exchanging heat between engine cooling water 7 and the T/M oil, a cooling water switching valve 9 for switching into a first state to distribute the engine cooling water into the second heat exchanger or into a second state to restrict the distribution of the engine cooling water, and an oil switching valve 10 for operating with the water pressure of the engine cooling water to switch into a distributing state to distribute the T/M oil into the first heat exchanger or into a restricting state to restrict the distribution of the T/N oil. The cooling water switching valve becomes the first state when the temperature of the engine cooling water is equal to or larger than a predetermined value, and becomes the second state when it is smaller than the predetermined value. The oil switching valve becomes the distributing state when the cooling water switching valve is in the second state and becomes the restricting state when it is in the first state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an oil temperature control device.

  Conventionally, there is a technique for increasing the temperature of transmission oil. For example, in Patent Document 1, a heat exchange pipe is provided in an oil pan on the bottom surface of a transmission, and engine oil is led to the heat exchange pipe from an oil filter portion of an engine oil circulation system through a supply pipe and circulated. A technology of an oil temperature adjusting device for a transmission that heats mission oil with engine oil is disclosed.

JP 2007-85457 A

  It is desirable that after the transmission warm-up is completed, it is possible to prevent the transmission oil from being excessively heated. Therefore, for example, cooling transmission oil with engine coolant has been studied. Here, there is a method of using a control switching valve when heat exchange is performed with three fluids of engine oil, transmission oil, and engine cooling water to control the oil temperature of the transmission oil. However, the use of expensive parts such as a solenoid valve increases the cost. It is desired that the warm-up of the transmission can be promoted and the excessive temperature rise of the transmission oil can be suppressed while suppressing an increase in cost.

  An object of the present invention is to provide an oil temperature control device that can warm up transmission oil and promote warm-up while suppressing an increase in cost due to the provision of a switching valve, and can suppress excessive temperature rise of the transmission oil. That is.

  The oil temperature control device of the present invention includes a first heat exchanger that exchanges heat between engine oil and transmission oil, a second heat exchanger that exchanges heat between engine coolant and transmission oil, and the second heat exchanger. A cooling water switching valve that switches between a first state in which the engine coolant flows through the exchanger and a second state in which the engine cooling water flows through the second heat exchanger; and the second heat exchanger, Switched between a distribution state in which transmission oil is circulated through the first heat exchanger and a regulation state in which transmission oil is circulated through the first heat exchanger. An oil switching valve, and the cooling water switching valve is in the first state when the temperature of the engine cooling water is equal to or higher than a predetermined value, and the temperature of the engine cooling water is When less than a fixed value, the second state is entered, and the oil switching valve is in the flow state when the cooling water switching valve is in the second state, and when the cooling water switching valve is in the first state. The regulation state is achieved.

  The oil temperature control device according to the present invention is a cooling that switches between a first state in which the engine cooling water is allowed to flow through the second heat exchanger and a second state that restricts the engine cooling water from flowing into the second heat exchanger. Operated by the water pressure of the engine cooling water flowing through the water switching valve and the second heat exchanger, the distribution state in which the transmission oil is circulated through the first heat exchanger, and the transmission oil is circulated through the first heat exchanger An oil switching valve that switches to a regulated state that regulates this. The oil switching valve is in a flow state when the cooling water switching valve is in the second state, and is in a restricted state when the cooling water switching valve is in the first state.

  When the temperature of the engine coolant is less than a predetermined value, the transmission oil is heated by exchanging heat with the engine oil. Further, when the temperature of the engine cooling water is equal to or higher than a predetermined value, the transmission oil is heated or cooled by heat exchange with the engine cooling water. An oil switching valve that operates by water pressure is less expensive than a solenoid valve or the like. Therefore, according to the oil temperature control device of the present invention, while suppressing the increase in cost due to the provision of the switching valve, the transmission oil is heated to promote warm-up, and the transmission oil is prevented from being excessively heated. There is an effect that can be done.

Drawing 1 is a figure showing the distribution state of the oil change-over valve in the oil temperature control device concerning an embodiment. FIG. 2 is a diagram illustrating a relationship between the kinematic viscosity and the loss torque of the oil according to the embodiment. Drawing 3 is a figure showing the regulation state of the oil change-over valve in the oil temperature control device concerning an embodiment. FIG. 4 is a diagram for explaining the transition of the cooling water temperature and each oil temperature. FIG. 5 is a diagram illustrating an oil temperature control device according to a first modification of the embodiment.

  Hereinafter, an oil temperature control device according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[Embodiment]
The embodiment will be described with reference to FIGS. 1 to 4. The present embodiment relates to an oil temperature control device. FIG. 1 is a diagram illustrating a flow state of an oil switching valve in an oil temperature control device according to an embodiment of the present invention, FIG. 2 is a diagram illustrating a relationship between kinematic viscosity and loss torque of the oil according to the embodiment, and FIG. These are the figures which show the control state of the oil switching valve in the oil temperature control apparatus which concerns on embodiment, and FIG. 4 is a figure explaining transition of a cooling water temperature and each oil temperature.

  As shown in FIG. 1, the vehicle 100 according to the embodiment includes an oil temperature control device 1, an engine 2, a transmission 3, and a radiator 11. The oil temperature control device 1 of the present embodiment includes a first heat exchanger 4, a second heat exchanger 5, a cooling water switching valve 9, and an oil switching valve 10.

  The engine 2 converts the combustion energy of the fuel into a rotational motion and outputs it. The engine 2 has engine oil 6 and engine cooling water 7. The engine oil 6 lubricates and cools each part in the engine 2. The engine cooling water 7 cools the cylinder head, the cylinder block, and the like of the engine 2. The rotation of the engine 2 is output to drive wheels via the transmission 3. The transmission 3 is an automatic transmission including, for example, a stepped or continuously variable transmission mechanism and a gear mechanism. The transmission 3 has transmission oil (hereinafter also referred to as “T / M oil”) 8. The T / M oil 8 lubricates and cools each part in the transmission 3. Vehicle 100 may be a hybrid vehicle. The transmission 3 of the hybrid vehicle preferably includes a rotating electric machine and a planetary gear mechanism instead of or in addition to the mechanical transmission mechanism.

The first heat exchanger 4 performs heat exchange between the engine oil 6 and the T / M oil 8. Here, first, an advantage of performing heat exchange between the engine oil 6 and the T / M oil 8 in the oil temperature control device 1 of the present embodiment will be described. In the present embodiment, as will be described below with reference to FIG. 2, the magnitude of the decrease in the loss torque in the transmission 3 per unit decrease in the kinematic viscosity ν of the T / M oil 8 | ΔTL _{T / M} / Δν _{T / M} | (= Tanβ) is larger than the magnitude | ΔTL _ENG / Δν _ENG | (= Tanα) of the loss torque increase amount in the engine 2 per unit increase amount of the kinematic viscosity ν of the engine oil 6. . The kinematic viscosity ν [mm ² / sec] is defined by the following formula (1). Here, δ: viscosity [Pa · sec], ρ: density [kg / m ³ ].
ν = δ / ρ (1)

In FIG. 2, the horizontal axis represents the kinematic viscosity ν [mm ² / sec], and the vertical axis represents the loss torque [Nm]. The loss torque TL _ENG of the engine 2 indicates a correspondence relationship between the value of the kinematic viscosity ν _ENG of the engine oil 6 and the magnitude of the loss torque of the engine 2. The line indicating the loss torque TL _ENG of the engine 2 of the present embodiment is, for example, a straight line obtained by linearly approximating (primary approximation) the value of the loss torque calculated from the measured value of the engine torque. The loss torque TL _ENG of the engine 2 is, for example, a differential torque between the theoretical output torque of the engine 2 and the actual output torque of the engine 2. The theoretical output torque of the engine 2 is, for example, that there is no drag loss due to the viscosity of the engine oil 6 when the value of the kinematic viscosity of the engine oil 6 is assumed to be 0, in other words, the viscosity of the engine oil 6. This is the output torque of the engine 2 when

  The loss torque TL line is preferably approximated to an actual measurement value (or a simulation calculation value) in a predetermined temperature range. The predetermined temperature range is, for example, an assumed environmental temperature range, a normal range temperature range, a temperature range determined in mode travel for fuel consumption calculation, or the like. The lower limit value of the predetermined temperature range is, for example, 25 ° C. or 0 ° C. The upper limit value of the predetermined temperature range is, for example, a steady temperature or a warm-up completion threshold temperature, and may be 80 ° C. as an example. The upper limit value of the predetermined temperature range may be a use limit temperature of the oils 6 and 8, for example, 120 ° C.

When the temperature of the engine oil 6 decreases due to heat exchange in the first heat exchanger 4, the kinematic viscosity ν _ENG of the engine oil 6 increases. The increase amount ΔTL _ENG of the loss torque of the engine 2 is determined according to the increase amount Δν _ENG of the kinematic viscosity accompanying the temperature decrease. The magnitude of the increase amount of the loss torque in the engine 2 per unit increase amount of the kinematic viscosity of the engine oil 6 | ΔTL _ENG / Δν _ENG | can be obtained as Tan α from the slope α of the loss torque TL _ENG . In the following description, the degree of change in loss torque in the engine 2 with respect to change in kinematic viscosity of the engine oil 6 is also referred to as “loss torque sensitivity Tanα of the engine 2”.

The loss torque TL _{T / M} of the transmission 3 indicates a correspondence relationship between the value of the kinematic viscosity ν _{T / M} of the T / M oil 8 and the magnitude of the output torque of the transmission 3. The loss torque TL _{T / M} of the transmission 3 is, for example, a differential torque between the input torque and the output torque of the transmission 3. The line indicating the loss torque TL _{T / M} of the transmission 3 is, for example, a straight line obtained by linearly approximating the value of the loss torque calculated from the measured values of the input torque and output torque of the transmission 3.

When the temperature of the T / M oil 8 increases due to heat exchange in the first heat exchanger 4, the kinematic viscosity ν _{T / M of} the T / M oil 8 decreases. The reduction amount ΔTL _{T / M} of the loss torque of the transmission 3 is determined according to the decrease amount Δν _{T / M} of the kinematic viscosity accompanying the temperature rise. The magnitude of the decrease amount of the loss torque in the transmission 3 per unit decrease amount of the kinematic viscosity of the T / M oil 8 | ΔTL _{T / M} / Δν _{T / M} | is determined from the slope β of the loss torque TL _{T / M.} It can be obtained as Tanβ. In the following description, the degree of change in the loss torque in the transmission 3 with respect to the change in the kinematic viscosity of the T / M oil 8 is also referred to as “loss torque sensitivity Tanβ of the transmission 3”.

In this specification, the temperature of the engine oil 6 is also referred to as “engine oil temperature T _EO ”. The temperature of the T / M oil 8 is also referred to as “T / M oil temperature T _TO ”. When the engine 2 is operating at a cold start or the like, the engine oil temperature T _EO generally rises faster than the T / M oil temperature T _TO . In other words, the engine oil temperature T _EO is higher than the T / M oil temperature T _TO . Accordingly, at the time of warming up, heat is applied from the engine oil 6 to the T / M oil 8 in the first heat exchanger 4. Due to this heat exchange, the engine oil temperature T _EO decreases and the torque loss of the engine 2 increases. On the other hand, the T / M oil temperature _TTO increases and the loss torque of the transmission 3 decreases.

Here, in the oil temperature control apparatus 1 of the present embodiment, as shown in FIG. 2, the loss torque sensitivity Tanβ of the transmission 3 is larger than the loss torque sensitivity Tanα of the engine 2. Accordingly, the loss torque decrease amount ΔTL _{T / M} of the transmission 3 corresponding to the decrease in the kinematic viscosity ν _{T / M} accompanying the increase in the T / M oil temperature T _TO due to the heat exchange in the first heat exchanger 4. Is larger than the magnitude of the increase amount ΔTL _ENG of the loss torque of the engine 2 according to the increase in the kinematic viscosity ν _ENG accompanying the decrease in the engine oil temperature T _EO due to heat exchange. As a result, the overall loss torque of the vehicle 100 can be reduced by reducing the magnitude of the overall loss torque TL _TTL , which is the _sum of the loss torque TL _ENG of the engine 2 and the loss torque TL _{T / M} of the transmission 3. Can do.

  Returning to FIG. 1, the first heat exchanger 4 includes a first inflow oil passage 4a, a first outflow oil passage 4b, a second inflow oil passage 4c, a second outflow oil passage 4d, and a heat exchange section 4e. ing. In the heat exchange part 4e, heat exchange between the engine oil 6 and the T / M oil 8 is performed. The engine oil 6 in the engine 2 flows into the heat exchange part 4e through the first inflow oil passage 4a. For example, the engine oil 6 is sent from the engine 2 to the heat exchange unit 4e by hydraulic pressure generated by an engine oil pump. The engine oil 6 after heat exchange flows into the engine 2 from the heat exchange part 4e via the first spilled oil passage 4b.

  The second inflow oil passage 4c connects the oil switching valve 10 and the heat exchange unit 4e. The second spilled oil passage 4 d is connected to the return oil passage 13 via the check valve 26. The return oil passage 13 connects the check valve 26 and the transmission 3. The check valve 26 allows the flow of the T / M oil 8 from the heat exchange part 4e side to the return oil path 13 side, and allows the flow of the T / M oil 8 from the return oil path 13 side to the heat exchange part 4e side. regulate. A bypass oil passage 12 is connected to the return oil passage 13. The bypass oil passage 12 connects the return oil passage 13 and the oil switching valve 10. The transmission 3 is connected to the oil switching valve 10 via the supply oil passage 14.

  The oil switching valve 10 is operated by the water pressure of the engine cooling water 7 that flows via the second heat exchanger 5 and switches between a distribution state and a regulation state. The distribution state of the oil switching valve 10 is a state in which the T / M oil 8 is circulated through the first heat exchanger 4 as shown in FIG. The restricted state of the oil switching valve 10 is a state that restricts the flow of the T / M oil 8 to the first heat exchanger 4 as shown in FIG. The oil switching valve 10 includes a return spring 10a, a water pressure introduction path 10b, and a valve body 10c. The water pressure introduction path 10b is connected to the downstream side water path 22b.

  The return spring 10a applies a biasing force toward one side in the axial direction to the valve body 10c. The water pressure guided to the valve body 10c from the downstream water path 22b through the water pressure introduction path 10b presses the valve body 10c in the direction opposite to the direction of the urging force by the return spring 10a.

  The engine cooling water 7 is cooled by the radiator 11. The radiator 11 is connected to the engine 2 via the inflow water channel 15. The radiator 11 is connected to the engine 2 via an outflow water channel 16, a control valve 17, a return water channel 18 and a water pump 19. The inflow water channel 15 guides the engine coolant 7 from the engine 2 to the radiator 11. The engine cooling water 7 cooled by the radiator 11 flows out from the outflow water channel 16. The control valve 17 is connected to the circulation water channel 20. The circulating water channel 20 is a water channel for circulating the engine cooling water 7 from the engine 2 to the engine 2 via the second heat exchanger 5 and the heater core 21. The downstream end of the circulation water channel 20 is connected to the control valve 17.

  The control valve 17 controls the flow rate of the engine coolant 7 that circulates between the radiator 11 and the engine 2. The control valve 17 shuts off the outflow water channel 16 and the return water channel 18 when the temperature of the engine cooling water 7 is low. Thereby, the circulation of the engine coolant 7 between the radiator 11 and the engine 2 is prohibited. When the water temperature of the engine cooling water 7 rises, the control valve 17 causes the outflow water channel 16 and the return water channel 18 to communicate with each other and circulates the engine cooling water 7 between the radiator 11 and the engine 2. The control valve 17 of the present embodiment prohibits the circulation of the engine coolant 7 between the radiator 11 and the engine 2 when the water temperature of the engine coolant 7 is lower than the predetermined value T1. The control valve 17 circulates the engine cooling water 7 between the radiator 11 and the engine 2 when the water temperature of the engine cooling water 7 is equal to or higher than the predetermined value T1.

  The control valve 17 further controls the flow rate of the engine cooling water 7 that circulates in the circulation water channel 20. For example, when the temperature of the engine cooling water 7 is low, the control valve 17 blocks the return water path 18 and the circulation water path 20 and circulates the engine cooling water 7 in the engine 2. When the temperature of the engine cooling water 7 rises, the control valve 17 causes the circulation water path 20 and the return water path 18 to communicate with each other and causes the engine cooling water 7 to circulate in the circulation water path 20. When the circulating water passage 20 and the return water passage 18 are communicated with each other by the control valve 17, the engine cooling water 7 discharged from the cylinder head of the engine 2 flows through the circulating water passage 20 toward the cooling water switching valve 9.

  The circulating water channel 20 branches into a first branch water channel 22 and a second branch water channel 23 at the cooling water switching valve 9. The first branch water channel 22 and the second branch water channel 23 are provided in parallel, and are connected to each other at the downstream junction 24. The first branch water channel 22 is a water channel that passes through the second heat exchanger 5. The first branch water channel 22 has an upstream water channel 22a and a downstream water channel 22b. The upstream water passage 22 a connects the cooling water switching valve 9 and the heat exchange part 5 c of the second heat exchanger 5. The downstream water channel 22b connects the heat exchange unit 5c and the junction unit 24. The second branch water channel 23 is a water channel that passes through the heater core 21.

  The second heat exchanger 5 performs heat exchange between the engine coolant 7 and the T / M oil 8. The second heat exchanger 5 includes an inflow oil passage 5a, an outflow oil passage 5b, and a heat exchange portion 5c. In the heat exchange part 5c, heat exchange between the engine coolant 7 and the T / M oil 8 is performed. The T / M oil 8 of the transmission 3 flows into the heat exchange part 5c via the inflow oil path 5a. The T / M oil 8 after heat exchange flows into the transmission 3 through the outflow oil passage 5b. The engine coolant 7 flows from the coolant switching valve 9 into the heat exchange unit 5 c through the upstream water passage 22 a of the first branch oil passage 22. The engine coolant 7 after the heat exchange flows from the heat exchange part 5c toward the junction part 24 via the downstream water channel 22b.

  The cooling water switching valve 9 switches between a first state where the engine cooling water 7 is allowed to flow through the second heat exchanger 5 and a second state where the engine cooling water 7 is restricted from flowing through the second heat exchanger 5. . The cooling water switching valve 9 of the present embodiment is in the first state when the temperature of the engine cooling water 7 is equal to or higher than the predetermined value T1, and is in the second state when the temperature of the engine cooling water 7 is lower than the predetermined value T1. The cooling water switching valve 9 is a switching valve that automatically switches between the first state and the second state according to the temperature of the engine cooling water 7, for example, and is a thermostat valve. FIG. 1 shows a second state of the cooling water switching valve 9. The cooling water switching valve 9 in the second state allows the engine cooling water 7 sent from the engine 2 to flow to the second branch water channel 23 and restricts the flow to the first branch water channel 22. Therefore, the cooling water switching valve 9 in the second state restricts the engine cooling water 7 from flowing through the second heat exchanger 5.

  A check valve 25 is provided in the downstream water channel 22 b of the first branch water channel 22. The check valve 25 allows the engine cooling water 7 to flow from the heat exchanging part 5c side to the merging part 24 side, and restricts the engine cooling water 7 from flowing from the merging part 24 side to the heat exchanging part 5c side. The water pressure introduction path 10b of the oil switching valve 10 is connected to the heat exchange part 5c side rather than the check valve 25 in the downstream side water path 22b. Accordingly, as shown in FIG. 1, when the cooling water switching valve 9 is in the second state and the engine cooling water 7 is not supplied to the first branch water passage 22, the valve body 10c of the oil switching valve 10 is provided via the water pressure introduction passage 10b. The water pressure acting on the water becomes less than a predetermined pressure.

  When the water pressure is less than the predetermined pressure, the urging force of the return spring 10 a is greater than the pressing force of the engine cooling water 7 due to the water pressure in the oil switching valve 10. Therefore, the oil switching valve 10 is in the flow state shown in FIG. 1 by the urging force of the return spring 10a. That is, the oil switching valve 10 is in a flow state when the cooling water switching valve 9 is in the second state. The oil switching valve 10 in the flow state communicates the supply oil passage 14 and the second inflow oil passage 4c. The T / M oil 8 in the transmission 3 is sent out to the supply oil passage 14 by the transmission oil pump, and flows into the heat exchange part 4e through the oil switching valve 10 and the second inflow oil passage 4c. The T / M oil 8 that has undergone heat exchange with the engine oil 6 in the heat exchanging section 4e flows out into the second outflow oil passage 4d. The T / M oil 8 flowing out to the second oil outflow passage 4d flows into the transmission 3 via the check valve 26 and the return oil passage 13.

  When the engine 2 is warmed up and the temperature of the engine coolant 7 becomes equal to or higher than the predetermined value T1, the coolant switching valve 9 is switched from the second state to the first state. Thereby, the cooling water switching valve 9 flows the engine cooling water 7 to the first branch water channel 22 as shown in FIG. The cooling water switching valve 9 in the first state also allows the engine cooling water 7 to flow into the second branch water channel 23. The engine coolant 7 flowing from the coolant switching valve 9 to the upstream water channel 22a of the first branch water channel 22 flows into the heat exchange unit 5c and exchanges heat with the T / M oil 8. The engine coolant 7 after the heat exchange flows out from the heat exchange part 5 c to the downstream water channel 22 b and flows toward the joining part 24 via the check valve 25. Further, the engine cooling water 7 after heat exchange flows into the water pressure introduction path 10b. By providing the check valve 25, a water pressure of a predetermined pressure or more acts on the valve body 10c of the oil switching valve 10 via the introduction path 10b.

  The water pressure equal to or higher than the predetermined pressure moves the valve body 10c against the urging force of the return spring 10a, and sets the oil switching valve 10 to the restricted state shown in FIG. That is, the oil switching valve 10 is in a restricted state when the cooling water switching valve 9 is in the first state. The restricted oil switching valve 10 communicates between the supply oil passage 14 and the bypass oil passage 12. Accordingly, the T / M oil 8 delivered from the transmission 3 to the supply oil passage 14 flows into the return oil passage 13 via the oil switching valve 10 and the bypass oil passage 12 and returns to the transmission 3. In other words, the regulated oil switching valve 10 bypasses the first heat exchanger 4 and circulates the T / M oil 8. When the oil switching valve 10 is in the restricted state, heat exchange between the engine 2 and the transmission 3 through the first heat exchanger 4 is not performed. As a result, as will be described below with reference to FIG. 4, the transmission 3 can be smoothly cooled during a high load.

In FIG. 4, the horizontal axis represents time, and the vertical axis represents temperature. FIG. 4 shows the water temperature (hereinafter simply referred to as “cooling water temperature”) T _EW , engine oil temperature T _EO , and T / M oil temperature T _TO of the engine cooling water 7.

In the region where the cooling water temperature _TEW is less than the predetermined value T1, the cooling water switching valve 9 is in the second state and restricts the engine cooling water 7 from flowing through the second heat exchanger 5. Therefore, heat exchange between the engine coolant 7 and the T / M oil 8 by the second heat exchanger 5 is not performed. Thereby, the delay in the rise of the cooling water temperature _TEW due to the heat deprived by the T / M oil 8 is suppressed. In the region where the coolant temperature T _EW is less than the predetermined value T1, the control valve 17 prohibits the cooling of the engine coolant 7 by the radiator 11 and promotes the increase of the coolant temperature T _EW . During the cooling water temperature T _EW is smaller than the predetermined value T1 is by heat exchange with the engine oil 6 and T / M oil 8 in the first heat exchanger 4, the temperature rise of the T / M oil temperature T _TO is promoted .

At time t1, the coolant temperature T _EW rises to a predetermined value T1, and the warm-up of the engine 2 is completed. In the oil temperature control device 1 of the present embodiment, the cooling water switching valve 9 is in the second state until the warm-up of the engine 2 is completed, and the increase in the cooling water temperature _TEW is promoted. By accelerating the warm-up of the engine 2, it is possible to suppress a delay in the start timing of control for fuel saving in the engine 2.

After the warm-up of the engine 2 is completed, the cooling of the engine coolant 7 by the radiator 11 is executed, and the coolant temperature _TEW is maintained at a predetermined value T1. When the cooling water temperature T _EW reaches the predetermined value T1, the cooling water switching valve 9 is in the first state, and the engine cooling water 7 is circulated through the second heat exchanger 5. As a result, heat exchange is performed between the engine coolant 7 and the T / M oil 8, and the increase in the T / M oil temperature _TTO is promoted. In the warm-up process from cold start, the coolant temperature T _EW is the highest, the T / M oil temperature T _TO is the lowest, and the engine oil temperature T _EO is between the coolant temperature T _EW and the T / M oil temperature T _TO. The temperature is often By starting heat exchange by the second heat exchanger 5 at time t1, heating of the T / M oil 8 by the engine coolant 7 is started. Thereby, the rise of T / M oil temperature _TTO is promoted. T / M oil temperature T _TO reaches a predetermined value T1 at time t2.

From time t2, the load on the vehicle 100 becomes high, and the engine oil temperature T _EO and the T / M oil temperature T _TO rise. In this case, if heat is exchanged not only in the second heat exchanger 5 but also in the first heat exchanger 4, there is a possibility that the T / M oil temperature _TTO cannot be efficiently cooled. Between the time t3 and the time t4, the relationship of following formula (2) is materialized. That is, the engine oil temperature T _EO is in the state higher than the cooling water temperature T high T / M oil temperature T _TO than _EW, and T / M oil temperature T _TO. If heat is exchanged in the first heat exchanger 4 in this state, the T / M oil 8 is heated by the relatively high temperature engine oil 6. That is, the T / M oil 8 is cooled by the engine cooling water 7 in the second heat exchanger 5, while being heated by the engine oil 6 in the first heat exchanger 4. Thereby, efficient cooling of the T / M oil 8 becomes difficult.
T _EW <T _TO <T _EO (2)

On the other hand, the oil temperature control device 1 according to the present embodiment is configured such that when the heat exchange between the engine coolant 7 and the T / M oil 8 is performed in the second heat exchanger 5, the water pressure of the engine coolant 7. As a result, the oil switching valve 10 is in a restricted state. When the oil switching valve 10 is in the restricted state, heat exchange between the engine oil 6 and the T / M oil 8 by the first heat exchanger 4 is prohibited. As a result, when the engine oil temperature T _EO becomes higher than the T / M oil temperature T _TO during high load operation of the vehicle 100, the T / M oil 8 is prevented from being heated. .

As described above, the oil temperature control device 1 of the present embodiment places the oil switching valve 10 in the restricted state by the water pressure when the engine cooling water 7 is flowing through the second heat exchanger 5. Therefore, the heat exchange by the three fluids of the engine oil 6, the engine coolant 7 and the T / M oil 8 is controlled without using a temperature sensor for detecting the coolant temperature T _EW or an expensive switching valve such as a solenoid valve. The warming up of the transmission 3 can be promoted, and the abnormal temperature rise of the T / M oil temperature _TTO can be suppressed. That is, the oil temperature control device 1 warms the T / M oil 8 to promote warm-up of the transmission 3 and suppresses the warm-up of the transmission 3 while suppressing an increase in cost due to the provision of the oil switching valve 10. After completion of the machine, there is an effect that excessive temperature rise of the T / M oil 8 can be suppressed. Further, the oil switching valve 10 is switched based on the water pressure of the engine cooling water 7 instead of the cooling water temperature _TEW . Therefore, it is not necessary to limit the location where the oil switching valve 10 is disposed in consideration of the influence of temperature, and the degree of freedom in arranging the oil switching valve 10 is high. Further, the oil switching valve 10 is mechanically operated by water pressure, so that the reliability of the oil temperature control device 1 is increased.

[First Modification of Embodiment]
A first modification of the embodiment will be described. FIG. 5 is a diagram illustrating an oil temperature control device according to a first modification of the embodiment. The oil temperature control device 101 of the first modification differs from the oil temperature control device 1 of the above embodiment in that the oil switching valve 40 is an electromagnetic valve. As shown in FIG. 5, the oil switching valve 40 includes a return spring 40a, an actuator 40b, and a valve body 40c. The actuator 40b applies an attractive force to the valve body 40c by electromagnetic force, and moves the valve body 40c against the urging force of the return spring 40a.

The hydraulic control device 101 includes a first heat exchanger 4, a second heat exchanger 5, a cooling water switching valve 9, an oil switching valve 40, a control unit 50, a water temperature sensor 51, and an engine oil temperature sensor 52. And a T / M oil temperature sensor 53. The water temperature sensor 51 detects the cooling water temperature T _EW of the upstream water channel 22a. A signal indicating the water temperature detected by the water temperature sensor 51 is output to the control unit 50. The engine oil temperature sensor 52 detects the engine oil temperature T _EO . A signal indicating the engine oil temperature T _EO detected by the engine oil temperature sensor 52 is output to the control unit 50. The T / M oil temperature sensor 53 detects the T / M oil temperature _TTO . A signal indicating the T / M oil temperature _TTO detected by the T / M oil temperature sensor 53 is output to the control unit 50.

The control unit 50 controls the oil switching valve 40. The control unit 50 determines _whether the coolant temperature T _EW acquired from the water temperature sensor 51, the engine oil temperature T _EO acquired from the engine oil temperature sensor 52, and the T / M oil temperature T _TO acquired from the T / M oil temperature sensor 53. When there is a relationship satisfying the above equation (2), the oil switching valve 40 is set to a restricted state. Thereby, heat exchange between the engine oil 6 and the T / M oil 8 is restricted, and the T / M oil 8 is efficiently cooled. On the other hand, when the acquired coolant temperature T _EW , engine oil temperature T _EO , and T / M oil temperature T _TO do not _{satisfy the} above equation (2), the control unit 50 puts the oil switching valve 40 into a flow state. Thereby, the temperature of the T / M oil 8 can be raised by both the engine coolant 7 and the engine oil 6.

[Second Modification of Embodiment]
A second modification of the embodiment will be described. The water pressure introduction passage 10b may be connected to the upstream water passage 22a or the like instead of the downstream water passage 22b. That is, the water pressure introduction path 10b only needs to be connected to a location where the water pressure of the engine cooling water 7 flowing via the second heat exchanger 5 can be introduced when the cooling water switching valve 9 is in the first state.

The cooling water switching valve 9 may be a switching valve that is switched by control instead of the switching valve that is mechanically switched by the cooling water temperature _TEW .

  The contents disclosed in the above embodiments and modifications can be executed in appropriate combination.

1,101 Oil temperature control device 2 Engine 3 Transmission (T / M)
4 First heat exchanger 5 Second heat exchanger 6 Engine oil 7 Engine cooling water 8 Transmission oil (T / M oil)
9 Cooling water switching valve 10, 40 Oil switching valve 10a, 40a Return spring 10b Water pressure introduction path 10c, 40c Valve body 20 Circulating water path 22 First branch water path 22a Upstream side water path 22b Downstream side water path T _EW Cooling water temperature T _EO Engine oil temperature T _TO T / M Oil temperature

Claims (1)

A first heat exchanger for exchanging heat between engine oil and transmission oil;
A second heat exchanger for exchanging heat between engine coolant and transmission oil;
A cooling water switching valve that switches between a first state in which engine coolant flows through the second heat exchanger and a second state in which engine cooling water is restricted from flowing through the second heat exchanger;
A flow state in which transmission oil is circulated through the first heat exchanger, and the transmission oil is circulated through the first heat exchanger. An oil switching valve that switches to a regulated state of regulation;
With
The cooling water switching valve is in the first state when the temperature of the engine cooling water is equal to or higher than a predetermined value, and is in the second state when the temperature of the engine cooling water is lower than a predetermined value.
The oil switching valve is in the flow state when the cooling water switching valve is in the second state, and is in the restricted state when the cooling water switching valve is in the first state. Temperature control device.

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