Cooling System of Internal Combustion Engine

Abstract

This cooling system which is for an internal combustion engine and which is mounted on a vehicle, comprises: an air conditioning device having a heat exchanger and mounted on the vehicle; a first passage which is connected to the heat exchanger and through which cooling water for the internal combustion engine is supplied to the heat exchanger; a second passage which is connected to a cooling device of oil of a transmission device connected to the internal combustion engine or oil filling the internal combustion engine, and through which the cooling water is supplied to the cooling device; a flowrate control valve for controlling the flowrate of the cooling water to the first passage and the second passage; and a control device that controls the internal combustion engine and the flowrate control valve. The control device executes first control for controlling the flowrate control valve to a position where the first and second passages open when the temperature of the oil is higher than that of the cooling water.

Description

Technical Field

[0001] The present disclosure relates to a cooling system for an internal combustion engine.

Background Art

[0002] Conventionally, a cooling system for an internal combustion engine having a passage for supplying cooling water to components that require cooling, such as a cylinder head and an exhaust circulation device of the internal combustion engine, is known (see, for example, Patent Document 1). Such a cooling system for an internal combustion engine has a passage for supplying cooling water to a radiator, and the cooling water is cooled by the radiator. Patent Document 1 discloses a cooling system for an internal combustion engine that has a flow control valve for controlling the flow rate of each passage and controls so that cooling water having an optimal flow rate flows through each passage.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 discloses a cooling system for an internal combustion engine that increases the amount of cooling water to a heater so that the heating performance does not deteriorate during idling stop. Further, Patent Document 1 discloses a cooling system for an internal combustion engine in which the cooling passage of the cylinder head remains open in order to cool the cylinder head and suppress knocking during idling stop. Patent Document 1 does not disclose a technique for improving the heating performance when the internal combustion engine 2 is in a non-combustion state.

[0005] An object of the present disclosure is to provide a cooling system for an internal combustion engine that can improve the heating performance of the internal combustion engine.

Means for Solving the Problems

[0006] The cooling system of an internal combustion engine according to the present disclosure is a cooling system of an internal combustion engine mounted on a vehicle, and includes an air conditioner mounted on the vehicle and having a heat exchanger, a first passage connected to the heat exchanger and supplying cooling water of the internal combustion engine to the heat exchanger, a second passage connected to a cooling device for oil of a transmission connected to the internal combustion engine or oil filled in the internal combustion engine and supplying the cooling water to the cooling device, a flow control valve for controlling the flow rate of the cooling water to the first passage and the second passage, and a control device for controlling the internal combustion engine and the flow control valve. When the oil temperature of the oil is higher than the water temperature of the cooling water, the control device executes a first control for controlling the flow control valve to a position where the first passage and the second passage are open.

[0007] According to this cooling system of the internal combustion engine, the control device controls the flow control valve to a position where the first passage and the second passage are open. As a result, heat is transferred from the cooling device through which oil having a temperature higher than that of the cooling water passes to the cooling water, and the heated cooling water flows to the heat exchanger of the air conditioner, and the heat exchanger is heated. As a result, the heating performance when the internal combustion engine is in a non-combustion state is improved.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a cooling system of an internal combustion engine that can improve the heating performance of the internal combustion engine.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following specification, based on the direction in which the cooling water flows, the upstream is referred to as the upstream and the downstream is referred to as the downstream as described in the specification.

[0011] As shown in FIG. 1, the cooling system 1 of the internal combustion engine 2 is a device that cools various devices of the internal combustion engine 2. The cooling system 1 of the internal combustion engine 2 includes a flow control valve (V) 4, a valve fitting (V / F) 6, a water pump (W / P) 8, a cylinder block (C / B) 10, a cylinder head (C / H) 12, an outlet fitting (O / F) 14, an exhaust gas recirculation cooler (EGR / C) 16, a heater core (H / C: an example of a heat exchanger) 18, a supercharger (T / C) 20, a throttle (Th / B) 22, a motor generator (M / G) 24, a transmission cooler (TM / C: an example of a cooling device) 26, an engine oil cooler (ENG / C) 28, a radiator (RA) 30, a hot bottle (HB) 32, and a control device 40. In the present embodiment, the internal combustion engine 2 is a reciprocating internal combustion engine 2 mounted on a vehicle, in which a piston (not shown) rotates a crankshaft.

[0012] Further, the cooling system 1 of the internal combustion engine 2 includes a plurality of passages for supplying cooling water to various devices. In the present embodiment, it includes a main engine cooling passage 50, a radiator passage 52, a heater passage (an example of the first passage) 54, a throttle warm water passage 56, an oil cooler passage (an example of the second passage) 58, and a supercharger cooling passage 60.

[0013] The flow control valve 4 is a device for adjusting the amount of cooling water flowing through the passage. In the present embodiment, it is a device for adjusting the amount of cooling water flowing through the radiator passage 52, the heater passage 54, and the oil cooler passage 58 (hereinafter sometimes referred to as each passage in the specification). In the present embodiment, the flow control valve 4 controls the flow rate of the cooling water flowing through each passage by varying the opening degree of the inlet where the cooling water enters the flow control valve 4 from each passage. In the present embodiment, the flow control valve 4 is a rotary valve having a rotary valve 4a. The flow control valve 4 changes the size of the opening area of the inlet of each passage by rotating the rotary valve 4a. Thereby, the flow control valve 4 can control the flow rate of the cooling water flowing through each passage. The flow control valve 4 is electrically connected to the control device 40, and the rotation angle of the valve is controlled by the control device 40. Further, the flow control valve 4 has a rotation angle sensor (not shown) for detecting the rotation angle ω of the rotary valve 4a, and transmits the rotation angle ω of the rotary valve 4a to the control device 40.

[0014] The flow control valve 4 has, as inlets through which the cooling water enters, a first inlet 4b directly connected to the rotary valve 4a, a second inlet 4c that bypasses the rotary valve 4a via the thermostat (T) 5 and is connected to the valve fitting 6, and a third inlet 4d that bypasses the second inlet 4c of the thermostat 5 and the rotary valve 4a and is connected to the valve fitting 6. The thermostat 5 opens the second inlet 4c when the paraffin wax melts when the cooling water reaches a predetermined temperature. The predetermined temperature is a temperature at which the cooling water may boil and the internal combustion engine 2 may overheat. The cooling water supplied to the third inlet 4d passes through the paraffin wax and melts the paraffin wax. The thermostat 5 has a spring that biases the thermovalve in a direction to close the second inlet 4c. Note that the thermostat 5 may be an existing thermostat 5, and a more detailed description thereof is omitted.

[0015] The valve fitting 6 is a cylindrical member attached to the cooling water outlet of the flow control valve 4. Downstream of the valve fitting 6, a water pump 8 for supplying cooling water to each passage is connected. In the present embodiment, the water pump 8 is a mechanical pump in which an impeller rotates by obtaining driving force from the crankshaft of the internal combustion engine 2.

[0016] Downstream of the water pump 8, the main engine cooling passage 50 is connected. The main engine cooling passage 50 includes a first water jacket (not shown) formed around the cylinder (not shown) of the cylinder block 10 and a second water jacket (not shown) formed in the vicinity of the exhaust port of the cylinder head. The main engine cooling passage 50 cools the cylinder block 10 and the cylinder head 12 by the cooling water passing through the first water jacket and the second water jacket.

[0017] The outlet fitting 14 is a cylindrical member that distributes the cooling water that has passed through the cylinder block 10 and the cylinder head 12 to each passage. In the present embodiment, the outlet fitting 14 is attached downstream of the second water jacket of the cylinder head 12. In the present embodiment, a water temperature sensor (an example of a temperature detection unit) 15 is provided on the outlet fitting 14. The water temperature sensor 15 detects the temperature (water temperature WT) of the cooling water passing through the outlet fitting 14. In other words, the water temperature sensor 15 detects the cooling water temperature before the cooling water is supplied to each passage. The water temperature sensor 15 is electrically connected to the control device 40 and transmits the detected water temperature WT to the control device 40.

[0018] The internal combustion engine 2 of this embodiment includes an exhaust gas recirculation device 17 including an exhaust gas recirculation valve (not shown), and introduces the exhaust gas of the internal combustion engine 2 into the intake air. The exhaust gas recirculation valve is electrically connected by a control device 40, and the amount of exhaust gas flowing into the intake air is adjusted by the exhaust gas recirculation valve. The exhaust gas recirculation cooler (an example of an exhaust gas recirculation cooling device) 16 is a heat exchanger that cools the exhaust gas recirculation gas (refer to the broken line in FIG. 1) introduced from the exhaust gas of the internal combustion engine 2 into the intake air by the exhaust gas recirculation device 17 with cooling water. The heater core 18 is a heat exchanger of an air conditioner (HVAC) 19 that supplies conditioned air to the interior of the vehicle. The heater core 18 absorbs heat from the cooling water and warms the conditioned air. The air conditioner 19 includes a blower fan 19a, and supplies the conditioned air heated by the heater core 18 into the interior by rotating the blower fan 19a. The air conditioner 19 includes an air conditioning control device 19b. The air conditioning control device 19b is electrically connected to the control device 40 by a communication line (not shown) and can acquire information transmitted from the control device 40. Similarly, the control device 40 can acquire information transmitted from the air conditioning control device 19b.

[0019] An outlet fitting 14 is connected to the exhaust gas recirculation cooler 16 and the heater core 18, and a heater passage 54 is connected thereto. The exhaust gas recirculation cooler 16 and the heater core 18 supply cooling water to the heater passage 54. The heater passage 54 is a passage formed by a rubber hose, a metal pipe, or the like. The heater passage 54 branches into a first heater passage 54a connected to a first inlet 4b of a flow control valve 4 downstream of the heater core 18 and a second heater passage 54b connected to a third inlet 4d. The second heater passage 54b is a passage for sensing the temperature of a thermostat 5. Specifically, when the cooling water becomes hot, the cooling water flowing through the second heater passage 54b melts the paraffin wax, and when the paraffin wax melts and the second inlet 4c opens, the cooling water is supplied to the radiator passage 52 regardless of the rotation angle ω of the rotary valve 4a.

[0020] The supercharger 20 is a device that supercharges the intake air of the internal combustion engine 2. A supercharger cooling passage 60 branched from upstream of the exhaust circulation gas cooler 16 of the heater passage 54 is connected to the supercharger 20. The cooling water flowing through the supercharger cooling passage 60 cools the turbine shaft of the supercharger 20. The supercharger cooling passage 60 is connected to the hot bottle 32.

[0021] The throttle 22 is a device that controls the intake air volume of the internal combustion engine 2. The motor generator 24 is an electric rotating machine connected to the internal combustion engine 2 and performs power generation and starting of the internal combustion engine 2. The throttle 22 and the motor generator 24 are connected to a throttle warm water passage 56 connected to the outlet fitting 14. The throttle warm water passage 56 is connected to the valve fitting 6 without passing through the radiator 30. The throttle warm water passage 56 prevents freezing of the throttle 22 and the motor generator 24 by allowing constantly warmed cooling water to flow.

[0022] The transmission cooler 26 is a heat exchanger that exchanges heat between the transmission oil filled in the transmission (an example of a transmission device) and the cooling water to raise or cool the temperature of the transmission oil. The engine oil cooler 28 is a heat exchanger that exchanges heat between the engine oil filled in the internal combustion engine 2 and the cooling water to raise or cool the temperature of the engine oil.

[0023] The transmission cooler 26 and the engine oil cooler 28 are connected to an oil cooler passage 58 branched from upstream of the throttle 22 in the throttle warm water passage 56, and the cooling water is supplied. The oil cooler passage 58 is connected to the first inlet 4b of the flow control valve 4.

[0024] The radiator 30 has an upper passage 30a (not shown), a radiator core 30b disposed downstream of the upper passage 30a, and a lower passage 30c disposed downstream of the radiator core 30b. The radiator core 30b has a plurality of fins and is a heat exchanger for exchanging heat between the cooling water and the outside air of the vehicle to cool the cooling water. The upper passage 30a of the radiator 30 is connected to a radiator passage 52 connected to the outlet fitting 14. The lower passage 30c of the radiator 30 is connected to a first radiator passage 52a connected to the first inlet 4b of the flow control valve 4 and a second radiator passage 52b connected to the second inlet 4c. The radiator passage 52 branches into the first radiator passage 52a and the second radiator passage 52b. Further, the radiator passage 52 branches into a third radiator passage 52c connected to the supercharger cooling passage 60 upstream of the radiator 30.

[0025] The hot bottle 32 functions as a reservoir tank for temporarily storing the cooling water and is a tank for venting air in the cooling water. The upstream of the hot bottle 32 is connected downstream of the connection portion between the third radiator passage 52c and the supercharger cooling passage 60 in the supercharger cooling passage 60. The downstream of the hot bottle 32 is connected downstream of the motor generator 24 of the throttle warm water passage 56. The cooling water that has passed through the supercharger 20 is supplied to the hot bottle 32.

[0026] The control device 40 is a device that controls the flow control valve 4 according to the water temperature WT acquired by the water temperature sensor 15, the running state of the vehicle, the operating state of the internal combustion engine 2, etc., and controls the flow rate of the cooling water. More specifically, the control device 40 determines the opening degree O of each passage, that is, the target rotation angle ωt of the rotary valve 4a, according to the water temperature WT, the running state of the vehicle, and the operating state of the internal combustion engine 2, and controls the flow rate of the cooling water flowing through each passage.

[0027] The graph in Fig. 2 shows that the horizontal axis represents the rotation angle ω of the rotary valve 4a, and the vertical axis represents the opening area (opening O). The control device 40 determines the target rotation angle ωt according to the water temperature WT, the running state of the vehicle, and the operating state of the internal combustion engine 2. The control device 40 rotates the rotary valve 4a toward the target rotation angle ωt. When the rotary valve 4a reaches the target rotation angle ωt, the opening O of each passage becomes a value corresponding to the target rotation angle ωt, and the flow rate of the cooling water flowing through each passage is controlled. That is, the control device 40 determining the target rotation angle ωt is synonymous with the control device 40 determining the target opening Ot. During this period, the control device 40 acquires the actual rotation angle ωr of the rotary valve 4a from the rotation angle sensor provided in the flow control valve 4 and monitors whether the actual rotation angle is following.

[0028] In addition, the flow control valve 4 of the present embodiment has a first stopper (an example of a restricting portion) that restricts the rotation of the rotary valve 4a at the position of the minimum rotation angle ωmin of the rotary valve 4a (for example, the position of -40 degrees in Fig. 2 in the present embodiment). Further, the flow control valve 4 has a second stopper (an example of a restricting portion) that restricts the rotation of the rotary valve 4a at the position of the maximum rotation angle ωmax (for example, the position of 210 degrees in Fig. 2 in the present embodiment). The control device 40 controls the rotary valve 4a in the section from the first stopper to the second stopper.

[0029] In addition, the control device 40 determines the introduction ratio of the exhaust recirculation gas and controls the opening of the exhaust recirculation valve so that the introduction amount of the exhaust recirculation gas becomes the determined introduction ratio with respect to the intake air amount. The control device 40 may determine the introduction ratio of the exhaust recirculation gas based on a map in which the introduction ratio of the exhaust recirculation gas is determined for each operating region of the internal combustion engine 2.

[0030] In addition, the control device 40 may execute control of each device such as a fuel injection valve (not shown), an exhaust circulation valve (not shown), and the supercharging pressure of the supercharger 20 so that the internal combustion engine 2 reaches a desired operating state based on values obtained from sensors such as an air flow sensor (not shown) and an accelerator position sensor (not shown). The desired operating state includes fuel cut-off that stops injection by the fuel injection valve and idle stop that stops the rotation of the internal combustion engine 2.

[0031] The control device 40 is actually an ECU (Electronic Control Unit) composed of a microcomputer including an arithmetic unit, a memory, an input / output buffer, etc. The control device 40 controls each device so that the internal combustion engine 2 reaches a desired operating state based on maps and programs stored in the memory. Note that various controls are not limited to software processing, and can also be processed by dedicated hardware (electronic circuits).

[0032] Next, the control procedure executed by the control device 40 will be described using the flowchart of FIG. 3. Note that the control device 40 starts the control operation when an ignition switch (not shown) is turned on.

[0033] In step S1, the control device 40 executes normal control (an example of the second control). In normal control, the control device 40 acquires the water temperature WT and the transmission oil temperature MT (hereinafter referred to as oil temperature MT in the specification), which is the temperature of the transmission oil filled in the transmission. The oil temperature MT may be acquired by a temperature sensor attached to the oil pan of the transmission or the like. Note that the control device 40 may use the temperature of the engine oil filled in the internal combustion engine 2 as the oil temperature MT. The temperature of the engine oil may be acquired by a temperature sensor attached to the oil pan of the internal combustion engine 2 or the like.

[0034] As shown in FIG. 4, in normal control, when the control device 40 is below the first predetermined water temperature WT1 and the oil temperature MT is below the first predetermined oil temperature MT1, the control device 40 sets the rotation angle ω of the rotary valve 4a to the position of P1. The first predetermined water temperature WT1 is, for example, a temperature of about 60°C. The first predetermined oil temperature MT1 is, for example, a temperature of about 10°C. However, the first predetermined water temperature WT1 and the first predetermined oil temperature MT1 may be changed as appropriate. By rotating and moving the rotary valve 4a to the position of P1 in this way, the control device 40 opens the heater passage 54 and the oil cooler passage 58. As a result, the temperature of the cooling water can be transmitted to the transmission oil and the engine oil, and the transmission oil and the engine oil can be heated. As a result, the friction of the internal combustion engine 2 and the transmission can be reduced.

[0035] When the water temperature WT is below the first predetermined water temperature WT1 and the oil temperature MT rises to the first predetermined oil temperature MT1 or higher, the control device 40 sets the rotation angle ω of the rotary valve 4a to the position of P2 and closes the oil cooler passage 58. As a result, the control device 40 ends the control of heating the engine oil and the transmission oil. By closing the oil cooler passage 58, the control device 40 prevents the heat of the cooling water from being taken away by the transmission oil and the engine oil, and promotes the temperature rise of the cooling water.

[0036] When the water temperature WT becomes equal to or higher than the first predetermined water temperature WT1, the control device 40 maintains the rotation angle ω of the rotary valve 4a at P2 as it is. When the water temperature WT becomes equal to or higher than the second predetermined water temperature WT2, the control device 40 rotates and moves the rotation angle ω of the rotary valve 4a to the position of P1. As a result, the control device 40 opens the oil cooler passage 58 and cools the engine oil and the transmission oil. The second predetermined water temperature WT2 is, for example, a temperature of about 79°C.

[0037] Furthermore, when the water temperature WT becomes equal to or higher than the third predetermined water temperature WT3, the control device 40 directly rotates the rotation angle ω of the rotary valve 4a to P3 or rotates it between P1 and P3 to open the radiator passage 52 and supply cooling water to the radiator 30. The third predetermined water temperature WT3 is, for example, a temperature of about 80°C. When the control device 40 executes normal control, it proceeds to step S2.

[0038] In step S2, the control device 40 determines whether or not the internal combustion engine 2 has entered a non-combustion state during normal control. The non-combustion state of the internal combustion engine 2 includes, for example, during an idle stop in which the internal combustion engine 2 temporarily stops and during a fuel cut in which the fuel injection valve does not inject fuel. In particular, the fuel cut is executed while the vehicle is traveling downhill or the like. While the internal combustion engine 2 is in a non-combustion state and no heat is generated, the cooling water is cooled by the traveling wind, so the temperature of the cooling water flowing through the heater core 18 decreases. As a result, the heating performance deteriorates. In order to suppress such a decrease in heating performance, the control device 40 executes the processes from step S2 to step S8. When the control device 40 determines that the internal combustion engine 2 is in a non-combustion state (step S2 YES), it proceeds to step S3.

[0039] In step S3, the control device 40 acquires the water temperature WT from the water temperature sensor 15 and determines whether or not the water temperature WT is lower than the first predetermined water temperature WT1. For example, during a fuel cut in normal control, the water temperature WT may decrease and enter a region where the water temperature WT is lower than the first predetermined water temperature WT1. When the control device 40 determines that the water temperature WT is lower than the first predetermined water temperature WT1 (step S3 YES), it proceeds to step S4.

[0040] In step S4, the control device 40 determines whether or not the oil temperature MT is higher than the second predetermined oil temperature MT2. The second predetermined oil temperature MT2 is, for example, a temperature of about 30°C. When the control device 40 determines that the oil temperature MT is higher than the second predetermined oil temperature MT2 (step S4 YES), it proceeds to step S5. At this time, since the control device 40 is executing normal control, the rotation angle ω of the rotary valve 4a is located at P2.

[0041] In step S5, the control device 40 determines whether the blower fan 19a is operating. When the blower fan 19a is operating, the influence of the decrease in the cooling water temperature on the heating performance is significant. Therefore, when the control device 40 determines that the blower fan 19a is operating (step S5 YES), the process proceeds to step S6.

[0042] In step S6, the control device 40 determines whether the oil temperature MT is higher than the water temperature WT. When the oil temperature MT is higher than the water temperature WT, the cooling water can be heated by the oil temperature MT. Therefore, when the control device 40 determines that the oil temperature MT is higher than the water temperature WT (step S6 YES), the process proceeds to step S7.

[0043] In step S7, the control device 40 determines whether it is in the idle stop state. In the present embodiment, the rotary valve 4a does not rotate during the idle stop. Therefore, when the control device 40 determines that it is not in the idle stop state (step S7 NO), the process proceeds to step S8.

[0044] In step S8, the control device 40 executes the first control to rotate the rotation angle ω of the rotary valve 4a to P1 even if the rotation angle ω of the rotary valve 4a is in a state where it is set to P2 in the normal control. In other words, the control device 40 executes the first control to control the rotary valve 4a to a position where the heater passage 54 is open and the oil cooler passage 58 is open. As a result, the cooling water flows through the oil cooler passage 58, heat is transferred from the transmission oil to the cooling water, and the cooling water can be heated. For this reason, the temperature of the cooling water in the heater passage 54 passing through the heater core 18 rises. As a result, the heating performance is improved.

[0045] Also, during the first control, the control device 40 suppresses the rotational speed of the blower fan 19a. Specifically, the rotational speed of the blower fan 19a is decreased compared to the normal control. Thereby, it is possible to prevent cold air-conditioning air from being supplied into the vehicle interior. When the control device 40 executes the first control, the process proceeds to step S9.

[0046] In step S9, the control device 40 determines whether the water temperature WT is equal to or higher than a first predetermined water temperature WT1. When the control device 40 determines that the water temperature WT is equal to or higher than the first predetermined water temperature WT1 (step S9: YES), the process proceeds to step S10. In step S10, the control device 40 ends the first control and proceeds with the process to step S1. Note that even if any one of steps S2 to S6 becomes NO during the first control, or if step S7 becomes YES, the control device 40 may end the first control and proceed with the process to step S1. When the water temperature WT is lower than the first predetermined water temperature WT1 (step S9: NO), the control device 40 proceeds with the process to step S8 and continues the first control.

[0047] When it is determined in step S2 that the non-combustion state does not exist (step S2: NO), when it is above the first predetermined water temperature WT1 in step S3 (step S3: NO), when the oil temperature MT is equal to or lower than a second predetermined oil temperature MT2 in step S4 (step S4: NO), when the blower fan is not operating in step S5 (step S5: NO), when the oil temperature MT is equal to or lower than the water temperature WT in step S6 (step S6: NO), and when it is in the idle stop state in step S7 (step S7: YES), the control device 40 does not execute the first control, returns the process to step S1, and executes normal control.

[0048] As described above, according to the cooling system 1 of the internal combustion engine 2 of the present disclosure, the control device controls the rotary valve 4a to a position where the heater passage 54 and the oil cooler passage 58 are open. As a result, heat is transferred from the transmission cooler 26 through which oil having a higher temperature than the cooling water passes to the cooling water, and the heated cooling water can flow to the heater core 18. For this reason, the heat exchanger of the air conditioner 19 is warmed. As a result, the heating performance when the internal combustion engine is in the non-combustion state is improved. Further, since it is possible to suppress a decrease in the temperature of the cooling water due to the driving of the air conditioner 19, it is possible to suppress a delay in warm-up of the internal combustion engine 2.

[0049] <Other Embodiments> The above describes the embodiments of the present disclosure. However, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the gist of the invention. In particular, a plurality of modifications described in this specification can be arbitrarily combined as needed.

[0050] (a) In the above embodiment, the flow control valve 4 was described by taking the rotary valve 4a as an example. However, the present disclosure is not limited thereto. The flow control valve 4 may be, for example, a flow control valve that controls the flow rate of each passage by a slide-type valve. In this case, the restricting portion may be a stopper that restricts the movement of the slide-type valve.

[0051] (b) In the above embodiment, an example was used in which the control device 40 controls the flow rate of the cooling water flowing through each passage by using the relationship between the opening area of each passage in FIG. 2 and the rotation angle ω of the rotary valve 4a. However, the present disclosure is not limited thereto. The control device 40 may control the flow control valve 4 by using, for example, a sensor that detects the flow rate. Further, the aperture area of each passage in FIG. 2 and the rotation angle ω of the rotary valve 4a may be appropriately changed.

Description of Reference Numerals

[0052] 1: Cooling system 2: Internal combustion engine 4: Flow control valve 18: Heater core 19: Air conditioner 19a: Blower fan 26: Transmission cooler 40: Control device 52: Radiator passage 54: Heater passage 58: Oil cooler passage

Claims

1. A cooling system for an internal combustion engine mounted on a vehicle, comprising: an air conditioner mounted on the vehicle and having a heat exchanger; a first passage connected to the heat exchanger for supplying cooling water of the internal combustion engine to the heat exchanger; a second passage connected to a cooling device for oil of a transmission connected to the internal combustion engine or oil filled in the internal combustion engine, for supplying the cooling water to the cooling device; a flow control valve for controlling the flow rate of the cooling water to the first passage and the second passage; a control device for controlling the internal combustion engine and the flow control valve; The control device executes a first control for controlling the flow control valve to a position where the first passage and the second passage are opened when the temperature of the cooling water is lower than a predetermined temperature and the temperature of the oil is higher than a predetermined temperature, and the temperature of the oil is higher than the temperature of the cooling water. When the temperature of the cooling water is lower than a predetermined temperature and the temperature of the oil is higher than a predetermined temperature, and the temperature of the oil is lower than the temperature of the cooling water, the control device executes a second control for controlling the flow control valve to a position where the first passage is opened and the second passage is closed. A cooling system for an internal combustion engine.

2. The control device prohibits the first control when the temperature of the cooling water is lower than a predetermined temperature and the temperature of the oil is lower than a predetermined temperature. The cooling system for an internal combustion engine according to Claim 1.

3. When the cooling water reaches the predetermined temperature or higher, the control device terminates the first control. The cooling system for an internal combustion engine according to Claim 1 or 2.

4. The air conditioner has a blower fan. The control device executes the first control while the blower fan is operating. The cooling system for an internal combustion engine according to Claim 1.

5. During the first control, the control device suppresses the rotational speed of the blower fan. The cooling system for an internal combustion engine according to Claim 4.

6. The control device executes the first control during fuel cut of the internal combustion engine. The cooling system for an internal combustion engine according to Claim 1.

7. When the internal combustion engine is in a non-combustion state during the second control and the temperature of the oil is higher than the temperature of the cooling water, the first control is executed. The cooling system for an internal combustion engine according to Claim 1. ​

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