Cooling system for internal combustion engine

Abstract

To provide a cooling system for an internal combustion engine capable of improving both of heater performance and warming-up performance of the internal combustion engine by using cooling water inside a cover.SOLUTION: A cooling system for an internal combustion engine includes: an air conditioner mounted to a vehicle; a first heater core disposed in an air-conditioned air passage through which air-conditioned air of the air conditioner passes; a second heater core disposed adjacent to the first heater core; a cover member that covers an exhaust pipe of the internal combustion engine mounted to the vehicle and having a cooling water passage through which cooling water passes; a first path that connects the cooling water passage and the first heater core and in which the cooling water flows; and a second path that is provided independently of the first path and connects the internal combustion engine and the second heater core and in which the cooling water flows.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to cooling systems for internal combustion engines. [Background technology]

[0002] Conventionally, there is known a cooling system for an internal combustion engine in which cooling water passes through the inside of a cover that covers an exhaust pipe (see, for example, Patent Document 1). The cooling system for an internal combustion engine in Patent Document 1 supplies cooling water passing through the internal combustion engine to a cooling water passage inside the cover during idling or the like, thereby keeping an exhaust purification device inside the exhaust pipe warm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 5-19518 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 does not disclose a technology for using the cooling water inside the cover for the heater core of an air conditioner. The objective of this disclosure is to provide a cooling system for an internal combustion engine that can improve both heater performance and warm-up performance of the internal combustion engine by using the cooling water inside the cover. [Means for solving the problem]

[0005] The cooling system for an internal combustion engine according to the present disclosure includes an air conditioning unit mounted on a vehicle, a first heater core arranged in an air conditioning air passage through which conditioned air from the air conditioning unit passes, a second heater core arranged adjacent to the first heater core, a cover member covering an exhaust pipe of the internal combustion engine mounted on the vehicle and having a coolant passage through which coolant passes, a first path connecting the coolant passage to the first heater core and through which coolant flows, and a second path provided independently of the first path, connecting the internal combustion engine to the second heater core and through which coolant flows. [Effects of the Invention]

[0006] According to this cooling system for an internal combustion engine, the coolant passing through the coolant passage receives heat from the exhaust pipe. The coolant heated by the heat from the exhaust pipe flows through the first path to the first heater core. The coolant in the first path passing through the coolant passage receives more heat and is more likely to warm up than the coolant in the second path passing through the internal combustion engine. Furthermore, the second path is provided independently of the first path. This prevents the heat of the coolant in the first path from being taken away by the internal combustion engine. This makes it easier for the first heater core to heat up. As a result, the heater performance of the air conditioner is improved. The second heater core adjacent to the first heater core receives heat from the first heater core. This makes it easier for the second heater core to warm up. This makes it easier for the temperature of the coolant passing through the second heater core to rise. As a result, warming up of the internal combustion engine is promoted. In this way, the cooling system for an internal combustion engine can improve both heater performance and warm-up performance. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a system diagram of an internal combustion engine cooling system according to one embodiment of the present disclosure; [Figure 2] 6 is a flowchart showing a control procedure of the first flow rate control executed by the control unit. [Figure 3] 6 is a flowchart showing a control procedure of the second flow rate control executed by the control unit. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0009] As shown in FIG. 1, the cooling system 1 for an internal combustion engine E includes an internal combustion engine E, a transmission TM, an air conditioning device 2, a first heater core 4, a second heater core 6, a cover member 8, a first path 10, a second path 12, a third path 14, a fourth path 16, an engine cooling path 18, and a control unit 20.

[0010] The internal combustion engine E is mounted on a vehicle. A cooling system 1 for the internal combustion engine E functions as a system for cooling the internal combustion engine E and supplying coolant to an air conditioning device 2. The internal combustion engine E has an exhaust pipe E1. The exhaust pipe E1 includes an exhaust collection section E2 and a catalyst section E3. Exhaust from the internal combustion engine E flows through the exhaust pipe E1. The exhaust collection section E2 collects exhaust from each cylinder of the internal combustion engine E. The catalyst section E3 is a section that houses a catalyst that purifies the exhaust. In this embodiment, the catalyst section E3 is arranged near the internal combustion engine E. Specifically, the catalyst section E3 is a front catalyst converter, and is located, for example, in the engine compartment (upstream from under the floor of the vehicle).

[0011] The air conditioner 2 is a device for supplying conditioned air into the vehicle cabin. The air conditioner 2 has a fan 2a, an evaporator 2b, a compressor 2c, a refrigerant passage 2d, and an air-conditioning air passage 2e. The fan 2a takes in outside air from the vehicle or air inside the vehicle into the air-conditioning air passage 2e. The evaporator 2b is a heat exchanger through which a refrigerant flows and exchanges heat between the refrigerant and the air. The compressor 2c pressurizes the refrigerant that has passed through the evaporator 2b and supplies the refrigerant to a condenser and an expansion valve (not shown). The air-conditioning air passage 2e is where the conditioned air passes.

[0012] The first heater core 4 is disposed in the air conditioning air passage 2e. The first heater core 4 is a heat exchanger through which coolant flows, passing through a cover member 8. The first heater core 4 heats the air conditioning air by exchanging heat between the coolant heated by heat from the exhaust pipe E1 and the air conditioning air.

[0013] The second heater core 6 is disposed adjacent to the first heater core 4 in the air conditioning air passage 2e. The second heater core 6 is a heat exchanger through which the coolant flowing through the internal combustion engine E flows. The second heater core 6 heats the air conditioning air by exchanging heat between the coolant heated by the internal combustion engine E and the air conditioning air.

[0014] The first heater core 4 is disposed upstream of the second heater core 6 in the air conditioning air passage 2e. The first heater core 4 and the second heater core 6 are disposed in close contact with each other, allowing them to exchange heat with each other. This allows heat to be transferred from the first heater core 4 to the second heater core along the flow of the air conditioning air. This facilitates the transfer of heat from the first heater core 4 to the second heater core. As a result, the warm-up of the internal combustion engine E is facilitated.

[0015] The cover member 8 covers the exhaust pipe E1. In this embodiment, the cover member 8 covers the catalyst section E3. The cover member 8 has a cooling water passage 8a through which cooling water passes. The cooling water passage 8a is formed inside the cover member 8, and the cooling water flows through it. The cooling water passage 8a exchanges heat between the exhaust pipe E1 and the cooling water (removes heat released from the exhaust pipe E1), thereby suppressing thermal damage caused by the exhaust pipe E1 to the area around the exhaust pipe E1. In this embodiment, the cover member 8 is a double-cylindrical passage formed by sheet metal or die-casting, and cooling water flows inside the circumferential surface.

[0016] The first path 10 is a path through which the coolant circulates so as to exchange heat between the first heater core 4 and the cover member 8. The first path 10 extends from the first heater core 4, passes through a coolant passage 8a, and is connected to the first heater core 4.

[0017] The first path 10 includes a first water pump 10a and a first valve 10b. The first water pump 10a is disposed upstream of the cover member 8 and circulates the coolant through the first path 10. In this embodiment, the first water pump 10a is an electric water pump that rotates an impeller using a motor. The first water pump 10a is electrically connected to the control unit 20, which controls the rotation of the motor. This controls the amount of coolant circulating per unit time (flow rate) through the first path 10. The first valve 10b is a valve that stops the circulation of coolant through the third path 14 and the fourth path 16. In this embodiment, the first valve 10b is disposed downstream of the cover member 8 and is closed to block the flow of coolant through the third path 14 and the fourth path 16. In this embodiment, the first valve 10b is an electromagnetic valve. The first valve 10b is electrically connected to the control unit 20. The opening and closing of the first valve 10b is controlled by the control unit 20. It should be noted that instead of one first valve 10b, one each may be provided in the third path 14 and the fourth path 16.

[0018] The second path 12 is a path through which coolant circulates to exchange heat between the second heater core 6 and the internal combustion engine E. The second path 12 branches off from an engine cooling path 18 that passes through the inside of the internal combustion engine E and is connected to the second heater core 6. The second path 12 returns from the second heater core 6 toward the internal combustion engine E and merges with the engine cooling path 18 upstream of the internal combustion engine E. In this embodiment, the second path 12 is connected to a thermostat 18b that is located upstream of the internal combustion engine E on the engine cooling path 18.

[0019] The second path 12 is independent from the first path 10, and the coolant circulates through each path independently. The second path 12 has a second valve 12a. The second valve 12a is a valve that stops the circulation of the coolant from the engine cooling path 18 to the second path 12. In this embodiment, the second valve 12a is provided immediately downstream of the internal combustion engine E, and is closed to block the flow of coolant to the second path 12. In this embodiment, the second valve 12a is an electromagnetic valve. The second valve 12a is electrically connected to the control unit 20. The opening and closing of the second valve 12a is controlled by the control unit 20.

[0020] The third path 14 is a path through which coolant circulates to exchange heat between the first heater core 4 and the cover member 8 and the first member 22. The third path 14 branches off from the first path 10 downstream of the cover member 8 and is connected to the first member 22, which is capable of exchanging heat with engine oil flowing through the internal combustion engine E. After passing through the first member 22, the third path 14 is connected upstream of the first water pump 10a. In this embodiment, the first member is an oil pan in which engine oil is stored. However, the first member 22 may be, for example, an engine oil cooler.

[0021] The fourth path 16 is a path through which the coolant circulates so as to exchange heat between the first heater core 4 and the cover member 8 and the second member 24. The fourth path 16 branches off from the first path 10 downstream of the cover member 8 and is connected to the second member 24, which is capable of exchanging heat with transmission oil flowing through the transmission TM. After passing through the second member 24, the fourth path 16 is connected upstream of the first water pump 10a. In this embodiment, the second member 24 is an oil pan in which transmission oil is stored. However, the second member 24 may also be, for example, a transmission oil cooler.

[0022] The engine cooling path 18 has a second water pump 18a, a thermostat 18b, a radiator 18c, and a water temperature sensor 18d. Coolant circulates through the engine cooling path 18, exchanging heat between the internal combustion engine E and the radiator 18c. The engine cooling path 18 passes through the cylinder head and cylinder block of the internal combustion engine E and is connected to the radiator 18c. The downstream side of the radiator 18c is connected to the thermostat 18b.

[0023] Second water pump 18a is disposed downstream of thermostat 18b and upstream of internal combustion engine E, and is a pump that circulates the coolant through second path 12 and engine cooling path 18. In this embodiment, second water pump 18a is an electric water pump that rotates an impeller using a motor. Second water pump 18a is electrically connected to control unit 20, which controls the rotation of the motor. This controls the circulation amount (flow rate) of the coolant flowing through second path 12 and engine cooling path 18 per unit time.

[0024] Thermostat 18b is a valve that controls the coolant flowing to radiator 18c. When the temperature of the coolant reaches a predetermined temperature (e.g., 80°C), thermostat 18b opens the valve, allowing the coolant to flow into radiator 18c and cooling the coolant. Radiator 18c is a heat exchanger that exchanges heat between the outside air and the coolant. Water temperature sensor 18d is provided downstream of internal combustion engine E and is a sensor that detects the temperature of the coolant (water temperature Tw). Water temperature sensor 18d is electrically connected to control unit 20. Furthermore, control unit 20 is electrically connected to an outside air temperature sensor 26 that detects the outside air temperature To of the vehicle and a room temperature sensor 28 that detects the temperature inside the vehicle's cabin (room temperature Tc).

[0025] The control unit 20 has a first flow control, a second flow control, and a heating control. The first flow control controls the flow rate of the first path 10 and the flow rate of the second path 12. The second flow control controls the flow rate of the third path 14 and the fourth path 16. The heating control controls the heating of the air conditioner 2. The control unit 20 is actually an ECU (Electronic Control Unit) configured by a microcomputer including a calculation device, a memory, an input / output buffer, etc. The control unit 20 controls each device based on maps and programs stored in the memory.

[0026] Next, a control procedure of the first flow rate control executed by the control unit 20 will be described with reference to Fig. 2. In this embodiment, an example will be described in which the control unit 20 acquires the room temperature Tc.

[0027] In step S1, the control unit 20 acquires the room temperature Tc from the room temperature sensor 28. After acquiring the room temperature Tc, the control unit 20 proceeds to step S2. In step S2, the control unit 20 acquires the water temperature Tw from the water temperature sensor 18d. After acquiring the water temperature Tw, the control unit 20 proceeds to step S3.

[0028] In step S3, the control unit 20 determines whether or not there is a heating request. Specifically, the control unit 20 executes heating control when the room temperature Tc is lower than the temperature set in the air conditioner 2. When executing heating control, the control unit 20 may determine that there is a heating request. When the control unit 20 determines that there is a heating request (step S3: YES), the process proceeds to step S4.

[0029] In step S4, the control unit 20 determines whether the room temperature Tc is less than a first predetermined temperature Tc1. The first predetermined temperature Tc1 is, for example, 0° C. If the control unit 20 determines that the room temperature Tc is less than the first predetermined temperature Tc1 (YES in step S4), the control unit 20 proceeds to step S5.

[0030] In step S5, the control unit 20 determines whether the water temperature Tw is less than a predetermined water temperature Tw1. The predetermined water temperature Tw1 is, for example, 80°C at which the internal combustion engine E has completed warming up and the thermostat 18b is fully open. If the water temperature Tw is less than the predetermined water temperature Tw1 (YES in step S5), the control unit 20 proceeds to step S6.

[0031] In step S6, the control unit 20 circulates the coolant through the first path 10 and the second path 12. In the flowchart of FIG. 2, circulating the coolant through the first path 10 is referred to as "first path open," and stopping the circulation of the coolant through the first path 10 is referred to as "first path closed." Circulating the coolant through the second path 12 is referred to as "second path open," and stopping the circulation of the coolant through the second path 12 is referred to as "second path closed." When circulating the coolant through the first path 10, the control unit 20 drives the first water pump 10a. When circulating the coolant through the second path 12, the control unit 20 opens the second valve 12a and drives the second water pump 18a. As a result, when the thermostat 18b is closed, the coolant circulates through the second path 12. When the cooling water flows through the first path 10 and the second path 12, the cooling water passing through the cover member 8 flows to the first heater core 4, and the cooling water passing through the internal combustion engine E flows to the second heater core 6. After executing the process of step S6, the control unit 20 proceeds to the process of step S1.

[0032] In this way, the control unit 20 circulates the coolant through the first heater core 4 and the second heater core 6 while executing heating control when the room temperature Tc is below the first predetermined temperature Tc1 and the water temperature Tw is below the predetermined water temperature Tw1, thereby supplying heat from both the cover member 8 and the internal combustion engine E to each heater core. This allows the conditioned air passing through the conditioned air passage 2e to be heated more quickly. As a result, the cold passenger compartment is warmed more quickly, improving heating performance.

[0033] In step S4, if the control unit 20 determines that the room temperature Tc is equal to or higher than the first predetermined temperature Tc1 (NO in step S4), the process proceeds to step S7. In step S7, the control unit 20 determines whether the water temperature Tw is lower than the predetermined water temperature Tw1. If the control unit 20 determines that the water temperature Tw is equal to or higher than the predetermined water temperature Tw1 (NO in step S7), the process proceeds to step S8.

[0034] Furthermore, in step S5, if the control unit 20 determines that the water temperature Tw is equal to or higher than the predetermined water temperature Tw1 (NO in step S5), the control unit 20 proceeds to step S8.

[0035] In step S8, the control unit 20 stops the circulation of the cooling water through the first path 10. The control unit 20 circulates the cooling water through the second path 12. When the thermostat 18b is open, the cooling water circulates through the second path 12 and the engine cooling path 18. When the cooling water flows through the second path 12, the cooling water that has passed through the internal combustion engine E flows to the second heater core 6. After executing the processing of step S8, the control unit 20 proceeds to the processing of step S1.

[0036] In this way, when the control unit 20 is performing heating control when the room temperature Tc is equal to or higher than the first predetermined temperature Tc1 and the water temperature Tw is equal to or higher than the predetermined water temperature Tw1, the control unit 20 does not circulate the coolant through the first path 10 but circulates the coolant through the second heater core 6. Also, when the control unit 20 is performing heating control when the room temperature Tc is lower than the first predetermined temperature Tc1 and the water temperature Tw is equal to or higher than the predetermined water temperature Tw1, the control unit 20 does not circulate the coolant through the first path 10 but circulates the coolant through the second heater core 6. This prevents heat from being transferred from the first heater core 4 to the second heater core 6, which would cause an excessive temperature rise in the second heater core 6. This makes it possible to prevent the temperature of the coolant in the engine cooling path 18 from rising excessively.

[0037] If the control unit 20 determines that the water temperature Tw is lower than the predetermined water temperature Tw1 (YES in step S7), the control unit 20 proceeds to step S9. In step S9, the control unit 20 circulates the cooling water through the first path 10 and stops the circulation of the cooling water through the second path 12. After executing the process of step S9, the control unit 20 proceeds to step S1.

[0038] In this way, while the control unit 20 is executing heating control when the room temperature Tc is equal to or higher than the first predetermined temperature Tc1 and the water temperature Tw is lower than the predetermined water temperature Tw1, the control unit 20 heats the conditioned air by the first heater core 4 on the first path 10, where the coolant temperature is likely to rise. Since the coolant does not circulate in the second path 12, no heat exchange with the conditioned air occurs, and heat is not taken from the coolant flowing through the internal combustion engine E. As a result, the warming up of the internal combustion engine E is promoted.

[0039] If the control unit 20 determines in step S3 that there is no heating request (NO in step S3), the control unit 20 proceeds to step S10. In step S10, the control unit 20 determines whether the water temperature Tw is less than a predetermined water temperature Tw1. If the control unit 20 determines that the water temperature Tw is equal to or greater than the predetermined water temperature Tw1 (NO in step S10), the control unit 20 proceeds to step S11. In step S11, the control unit 20 stops the circulation of the cooling water through the first path 10 and the second path 12. After executing the process of step S11, the control unit 20 proceeds to step S1. On the other hand, if the control unit 20 determines that the water temperature Tw is less than the predetermined water temperature Tw1 (NO in step S10), the control unit 20 proceeds to step S6, where the control unit 20 stops the circulation of the cooling water through the first path 10 and the second path 12.

[0040] In this way, when there is no heating request and the water temperature Tw is lower than the predetermined water temperature Tw1, the control unit 20 circulates the coolant through the first path 10 and the second path 12, so that heat from the first heater core 4 is transferred to the second heater core 6 and the coolant through the second path 12 is warmed. This makes it easier for the temperature of the coolant passing through the internal combustion engine E to rise, accelerating the warm-up of the internal combustion engine E. When the water temperature Tw of the coolant passing through the internal combustion engine E becomes equal to or higher than the predetermined water temperature Tw1, the control unit 20 stops the circulation through the first path 10 and the second path 12 to prevent an excessive rise in the temperature of the coolant.

[0041] Next, a control procedure of the second flow rate control executed by the control unit 20 will be described with reference to Fig. 3. In this embodiment, an example will be described in which the control unit 20 acquires the room temperature Tc. Furthermore, when the cooling water in the first path 10 is circulating, the control unit 20 executes the second flow rate control.

[0042] In step S201, the control unit 20 acquires the room temperature Tc from the room temperature sensor 28. After acquiring the room temperature Tc, the control unit 20 proceeds to step S202. In step S202, the control unit 20 determines whether the room temperature Tc is less than a second predetermined temperature Tc2. The second predetermined temperature Tc2 is a temperature higher than the first predetermined temperature Tc1. The second predetermined temperature Tc2 is, for example, 15°C. If the control unit 20 determines that the room temperature Tc is less than the second predetermined temperature Tc2 (YES in step S202), the control unit 20 proceeds to step S203.

[0043] In step S203, the control unit 20 determines whether or not there is a heating request. If the control unit 20 determines that there is a heating request (YES in step S203), the process proceeds to step S204.

[0044] In step S204, the control unit 20 stops the circulation of the cooling water through the third path 14 and the fourth path 16. Specifically, the control unit 20 closes the first valve 10b to prevent the cooling water from the first path 10 from flowing into the third path 14 and the fourth path 16.

[0045] In step S202, if the control unit 20 determines that the room temperature Tc is equal to or higher than the second predetermined temperature Tc2 (NO in step S202), the control unit 20 proceeds to step S205. In step S203, if the control unit 20 determines that there is no heating request (NO in step S203), the control unit 20 proceeds to step S205.

[0046] In step S205, the control unit 20 circulates the cooling water in the third path 14 and the fourth path 16. Specifically, the control unit 20 opens the first valve 10b to allow the cooling water in the first path 10 to flow into the third path 14 and the fourth path 16.

[0047] In this way, when the room temperature Tc is lower than the second predetermined temperature Tc2, the control unit 20 stops the circulation of the coolant through the third path 14 and the fourth path 16 and transfers all of the heat of the coolant received from the cover member 8 to the first heater core 4, prioritizing the heating of the air-conditioned air. This improves heating performance. On the other hand, when there is no heating request or when the room temperature Tc is equal to or higher than the second predetermined temperature Tc2, the control unit 20 circulates the coolant through the third path 14 and the fourth path 16. This warms the oil in the internal combustion engine E and the transmission, thereby warming them up and reducing friction.

[0048] As described above, according to the cooling system 1 for the internal combustion engine E of the present disclosure, the coolant passing through the coolant passage 8a receives heat from the exhaust pipe E1. The coolant heated by the heat from the exhaust pipe E1 flows through the first path 10 to the first heater core 4. The coolant passing through the first path 10, which passes through the coolant passage 8a, receives more heat and is more likely to warm up than the coolant passing through the second path 12, which passes through the internal combustion engine E. This is because the exhaust pipe E1 is more likely to reach a higher temperature than the main body of the internal combustion engine E, or because the exhaust pipe E1 does not need to be actively cooled, allowing the amount of coolant supplied to the coolant passage 8a to be reduced. Furthermore, the second path 12 is provided independently of the first path 10. This prevents the heat from the coolant passing through the first path 10 from being absorbed by the internal combustion engine E. Therefore, the first heater core 4 is more likely to be heated. As a result, the heater performance of the air conditioner 2 is improved. The second heater core 6 adjacent to the first heater core 4 receives heat from the first heater core 4. This makes it easier for the second heater core 6 to warm up. This makes it easier for the temperature of the coolant passing through the second heater core 6 to rise. As a result, the warm-up of the internal combustion engine E is promoted. In this way, the cooling system 1 for the internal combustion engine E can improve both the heater performance and the warm-up performance.

[0049] <Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible within the scope of the gist of the invention. In particular, the multiple modifications described in this specification can be arbitrarily combined as necessary.

[0050] (a) In the above embodiment, an example was described in which the room temperature Tc was acquired, but the present disclosure is not limited to this. The control unit 20 may acquire the outside air temperature To by the outside air temperature sensor 26.

[0051] (b) In the above embodiment, the first water pump 10a and the second water pump 18a are described as electric water pumps, but the present disclosure is not limited to this. Each water pump may be a mechanical pump driven by the internal combustion engine E. In this case, a clutch may be used to control the activation and deactivation of the mechanical pump. [Explanation of symbols]

[0052] 1: Cooling system 2: Air conditioner, 2e: Air conditioning passageway 4: First heater core, 6: Second heater core 8: Cover member, 8a: Cooling water passage 10: first path, 10a: first water pump, 10b: first valve 12: Second path, 12a: Second valve 14: 3rd pathway, 16: 4th pathway 18: Engine cooling path, 18a: Second water pump, 18b: Thermostat 20: control section, 22: first member, 24: second member E: Internal combustion engine, E1: Exhaust pipe, TM: Transmission Tc: room temperature, Tc1: first predetermined temperature, Tc2: second predetermined room temperature, To: outside temperature Tw: water temperature, Tw1: predetermined water temperature

Claims

1. an air conditioning device mounted on a vehicle; a first heater core disposed in an air conditioning air passage through which air conditioning air of the air conditioner passes; a second heater core disposed adjacent to the first heater core; a cover member that covers an exhaust pipe of an internal combustion engine mounted on the vehicle and has a cooling water passage through which cooling water passes; a first path connecting the cooling water passage and the first heater core; a second path provided independently of the first path, connecting the internal combustion engine and the second heater core, and through which cooling water flows; A cooling system for an internal combustion engine comprising:

2. The first heater core is disposed upstream of the second heater core in the air conditioning air passage.

2. The cooling system for an internal combustion engine according to claim 1.

3. a first flow rate control that controls a flow rate of the first path and a flow rate of the second path; a heating control for controlling heating of the air conditioner; a control unit having the control unit, while executing the heating control, acquires an outside air temperature or a room temperature inside the vehicle and a water temperature of the coolant in the second path, and, when the outside air temperature or the room temperature is equal to or higher than a first predetermined temperature and the water temperature is lower than a predetermined water temperature, circulates the coolant in the first path and stops the circulation of the coolant in the second path.

2. The cooling system for an internal combustion engine according to claim 1.

4. a first flow rate control that controls a flow rate of the first path and a flow rate of the second path; a heating control for controlling heating of the air conditioner; a control unit having the control unit acquires an outside air temperature or a room temperature of the vehicle and a water temperature of the coolant in the second path while performing the heating control, and circulates the coolant in the first path and the second path when the outside air temperature or the room temperature is lower than a first predetermined temperature and the water temperature is lower than a predetermined water temperature.

2. The cooling system for an internal combustion engine according to claim 1.

5. a first flow rate control that controls a flow rate of the first path and a flow rate of the second path; a heating control for controlling heating of the air conditioner; a control unit having the control unit, while executing the heating control, acquires an outside air temperature or a room temperature of the vehicle and a water temperature of the coolant in the second path, and when the outside air temperature or the room temperature is equal to or higher than a first predetermined temperature and when the water temperature is equal to or higher than a predetermined water temperature, stops circulation of the coolant in the first path and circulates the coolant in the second path.

2. The cooling system for an internal combustion engine according to claim 1.

6. a first flow rate control that controls a flow rate of the first path and a flow rate of the second path; a heating control for controlling heating of the air conditioner; a control unit having the control unit acquires a water temperature of the cooling water in the second path while the heating control is stopped, and when the water temperature is lower than a predetermined water temperature, circulates the cooling water in the first path and the cooling water in the second path, and when the water temperature is equal to or higher than the predetermined water temperature, stops the circulation of the cooling water in the first path and the cooling water in the second path.

2. The cooling system for an internal combustion engine according to claim 1.

7. engine oil flowing inside the internal combustion engine; transmission oil flowing inside a transmission mounted on the vehicle; a third path branching from the first path and connected to a first member capable of heat exchange with the engine oil; a fourth path branching from the first path and connected to a second member capable of heat exchange with the transmission oil; Equipped with The control unit a second flow rate control that controls the flow rates of the third path and the fourth path; a heating control for controlling heating of the air conditioner; and the control unit acquires an outside air temperature or a room temperature of the vehicle through the first path while the heating control is being performed, and when the room temperature is lower than a second predetermined temperature that is higher than a first predetermined temperature, stops the circulation of the cooling water through the third path and the fourth path; the control unit circulates the cooling water through the third path and the fourth path when the heating control is stopped or when the temperature is equal to or higher than the second predetermined temperature.

7. A cooling system for an internal combustion engine according to any one of claims 1 to 6.

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