Vehicle cooling system

Abstract

To provide a vehicle cooling system that can suppress the temperature rise of the coolant. [Solution] The cooling system 10 includes a cooling oil circuit 20 that circulates cooling oil to cool the vehicle's transaxle unit 21, and a cooling water circuit 30 that circulates cooling water to cool the cooling oil. The cooling water circuit 30 includes an oil cooler 22 that exchanges heat with the cooling oil, a water pump 31 that adjusts the flow rate of the cooling water, a radiator 32 that cools the cooling water, a radiator fan 33 that adjusts the amount of air blown to the radiator 32, and a control device 50 that controls the output of the water pump 31 or the radiator fan 33. The control device 50 controls the output of the water pump 31 or the radiator fan 33 according to the temperature of the cooling water, and also controls the output of the water pump 31 or the radiator fan 33 according to the temperature of the cooling oil.

Description

[Technical Field]

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

[0002] A cooling system is mounted on a vehicle and cools a cooled portion of the vehicle. The cooling system includes, for example, a cooling oil circuit that circulates cooling oil for cooling a drive unit of the vehicle, and a cooling water circuit that circulates cooling water for cooling the cooling oil.

[0003] The cooling water circuit includes, for example, an oil cooler that exchanges heat with the cooling oil, a water pump that adjusts the flow rate of the cooling water, a radiator that cools the cooling water, a radiator fan that adjusts the amount of air blown to the radiator, and a control device that controls the output of the water pump or the output of the radiator fan. In a cooling system, the control device controls the output of the water pump or the output of the radiator fan in accordance with the temperature of the cooling water (e.g., Patent Document 1). [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2020-100189 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] For example, when controlling the flow rate of cooling water or the amount of air blown to the radiator in accordance with the temperature of cooling water when the outside air temperature is high, the flow rate of cooling water increases in accordance with the temperature of cooling water, or the amount of air blown to the radiator also increases, so the cooling oil can be sufficiently cooled. On the other hand, when the outside air temperature is low, the cooling water is sufficiently cooled in the radiator, so when controlling the flow rate of cooling water or the amount of air blown to the radiator in accordance with the temperature of cooling water, the flow rate of cooling water decreases in accordance with the temperature of cooling water, and the amount of air blown to the radiator also decreases.

[0006] In this case, the drive unit generates more heat as the rotational speed increases. Therefore, for example, during high-speed operation when the ambient temperature is low, if the coolant flow rate is low and the amount of air blown to the radiator is also low, it may not be possible to remove all the heat from the coolant, causing the coolant temperature to rise.

[0007] Therefore, the present invention aims to provide a vehicle cooling system that can suppress the temperature rise of the coolant. [Means for solving the problem]

[0008] The vehicle cooling system according to the present invention comprises a cooling oil circuit for circulating cooling oil to cool the drive unit of a vehicle, and a cooling water circuit for circulating cooling water to cool the cooling oil. The cooling water circuit includes an oil cooler for heat exchange with the cooling oil, a water pump for adjusting the flow rate of the cooling water, a radiator for cooling the cooling water, a radiator fan for adjusting the amount of air supplied to the radiator, and a control device for controlling the output of the water pump or the radiator fan. The control device controls the output of the water pump or the radiator fan according to the temperature of the cooling water, and also controls the output of the water pump or the radiator fan according to the temperature of the cooling oil.

[0009] With the above configuration, the temperature rise of the coolant can be suppressed by controlling the output of the water pump or the radiator fan not only according to the temperature of the coolant but also according to the temperature of the coolant.

[0010] In the vehicle cooling system according to the present invention, it is preferable to increase the output of the water pump when the vehicle is in motion and the temperature of the coolant is above a predetermined temperature.

[0011] When the ambient temperature is low, the coolant is sufficiently cooled in the radiator. Therefore, when controlling the coolant flow rate or the amount of air supplied to the radiator according to the coolant temperature, the coolant flow rate and the amount of air supplied to the radiator will decrease according to the coolant temperature. However, the drive unit generates more heat as the drive speed increases. For example, during high-speed operation when the ambient temperature is low, if the coolant flow rate and the amount of air supplied to the radiator are low, the heat from the coolant may not be sufficiently removed, causing the coolant temperature to rise. With the above configuration, when the vehicle is running and the coolant temperature is above a predetermined temperature, the output of the water pump is increased. This increases the coolant flow rate and reduces the coolant temperature.

[0012] In the vehicle cooling system according to the present invention, it is preferable that the control device increases the output of the radiator fan when the vehicle is stopped and the temperature of the coolant is above a predetermined temperature.

[0013] When the vehicle is stopped, the flow rate of the coolant is low, so even if the amount of coolant that exchanges heat with the coolant is increased, the heat exchange efficiency between the coolant and the coolant is poor. With the above configuration, when the vehicle is stopped and the temperature of the coolant is above a predetermined temperature, the output of the radiator fan is increased. This reduces the temperature of the coolant and thus the temperature of the coolant.

[0014] In the vehicle cooling system according to the present invention, it is preferable that the control device controls the output of the water pump or the output of the radiator fan according to the temperature of the air blown by the radiator fan.

[0015] With the above configuration, the heat absorption and dissipation in the radiator can be calculated, allowing for more precise control of the cooling system. [Effects of the Invention]

[0016] According to the vehicle cooling system of the present invention, it is possible to suppress the temperature rise of the cooling oil. [Brief explanation of the drawing]

[0017] [Figure 1] It is a block diagram showing a configuration of a cooling system which is an example of an embodiment. [Figure 2] It is a block diagram showing a configuration of a control device which is an example of an embodiment. [Figure 3] It is a flow chart showing a flow of second cooling control which is an example of an embodiment. Mode for Carrying Out the Invention

[0018] Hereinafter, an example of an embodiment of the present invention will be described in detail. In the following description, specific shapes, materials, directions, numerical values and the like are exemplifications for facilitating understanding of the present invention, and can be appropriately changed according to applications, purposes, specifications and the like.

[0019] [Cooling System] The configuration of a cooling system 10 which is an example of an embodiment will be described with reference to FIG. 1.

[0020] The cooling system 10 is mounted on a vehicle, and cools a cooled portion of the vehicle. The cooling system 10 includes a cooling oil circuit 20 that circulates cooling oil for cooling a drive unit of the vehicle, a cooling water circuit 30 that circulates cooling water for cooling the cooling oil, and a control device 50 that controls each device of the cooling system 10.

[0021] According to the cooling system 10, although details will be described later, a temperature rise of the cooling oil can be suppressed. In particular, the temperature rise of the cooling oil can be suppressed when the outside air temperature is low and the vehicle is driving at high speed.

[0022] The vehicle according to the present embodiment is, for example, a hybrid electric vehicle (HEV), which travels by combining power sources of an engine and a motor. Although the vehicle according to the present embodiment is a hybrid vehicle, the present invention is not limited thereto. The vehicle of the present invention may be an engine vehicle that travels by an engine, a battery electric vehicle (BEV) that travels by rotating a motor with electric power charged in a battery, or the like.

[0023] The drive unit of the vehicle according to the present embodiment is, for example, a transaxle unit 21. Although the drive unit of the vehicle according to the present embodiment is the transaxle unit 21, the present invention is not limited thereto. The drive unit of the vehicle according to the present invention may be an automatic transmission or the like.

[0024] As described above, the cooling oil circuit 20 circulates cooling oil to cool the transaxle unit 21. The cooling oil circuit 20 may be configured to cool devices other than the transaxle unit 21. Devices other than the transaxle unit 21 may include a power control unit, a counter gear unit, a differential gear unit, and the like.

[0025] The cooling oil circuit 20 includes an oil cooler 22. The oil cooler 22 is a heat exchanger for performing heat exchange between the cooling oil circulating in the cooling oil circuit 20 and the cooling water circulating in the cooling water circuit 30.

[0026] The cooling oil circuit 20 is provided with a cooling oil temperature sensor 23 that detects the temperature of the cooling oil. The cooling oil temperature sensor 23 is connected to a control device 50.

[0027] The cooling oil cools the heat generated inside the transaxle unit 21 to prevent overheating. The cooling oil may also have a lubricating effect to lubricate the gears and other parts inside the transaxle unit 21, a power transmission effect to properly transmit power to the transaxle unit 21, and a cleaning effect to adsorb wear dust and dirt generated inside the transaxle unit 21.

[0028] As described above, the cooling water circuit 30 cools the cooling oil by circulating the cooling water. The cooling water circuit 30 may also be configured to cool and lubricate other equipment. The cooling water circuit 30 includes an oil cooler 22, a water pump 31, a radiator 32, and a radiator fan 33, each of which will be described in detail later.

[0029] Coolant is a liquid used to cool the cooling components of a vehicle. Also known as coolant, it comes in various types, including inorganic salt-based coolants, organic acid-based coolants, and mixed coolants. The main components of coolant are ethylene glycol, propylene glycol, preservatives, rust inhibitors, and water.

[0030] The water pump 31 discharges coolant in the coolant circuit 30 by driving a motor. The amount of coolant circulating in the coolant circuit 30 can be adjusted by adjusting the output of the water pump 31. The output of the water pump 31 may be adjusted, for example, by controlling the duty cycle of the voltage applied to the motor. The water pump 31 is connected to the control device 50.

[0031] The radiator 32 is a heat exchanger that dissipates the heat from the coolant into the air. The radiator 32 can cool the coolant.

[0032] The radiator fan 33 is a fan that blows air toward the radiator 32. The radiator fan 33 is driven by a motor. The amount of air blown toward the radiator 32 can be adjusted by controlling the output of the radiator fan 33. The output of the radiator fan 33 may also be adjusted by controlling the rotational speed of the motor. The radiator fan 33 is connected to the control device 50.

[0033] The cooling water circuit 30 is equipped with a cooling water temperature sensor 35 for detecting the temperature of the cooling water. The cooling water temperature sensor 35 is connected to the control device 50.

[0034] Furthermore, an airflow temperature sensor 36 is provided near the radiator fan 33 to detect the airflow temperature of the radiator fan 33. The airflow temperature sensor 36 is connected to the control device 50.

[0035] [Control device] Using Figure 2, we will describe the configuration of a control device 50, which is an example of an embodiment.

[0036] The control device 50 has a CPU (Central Processing Unit) which is an arithmetic processing unit, and memory units such as RAM (Random Access Memory) and ROM (Read Only Memory). It performs signal processing according to a program pre-stored in ROM while utilizing the temporary storage function of RAM.

[0037] The control device 50 includes a first cooling control unit 51, a second cooling control unit 52, and a third cooling control unit 53. The first cooling control unit 51, the second cooling control unit 52, and the third cooling control unit 53 are implemented by the CPU executing a program stored in ROM or RAM.

[0038] The first cooling control unit 51 controls the output of the water pump 31 or the radiator fan 33 according to the temperature of the coolant detected by the coolant temperature sensor 35. More specifically, the first cooling control unit 51 increases the output of the water pump 31 when the temperature of the coolant detected by the coolant temperature sensor 35 is above a predetermined temperature. This increases the flow rate of the coolant and suppresses the rise in the temperature of the coolant. Alternatively, the first cooling control unit 51 increases the output of the radiator fan 33 when the temperature of the coolant detected by the coolant temperature sensor 35 is above a predetermined temperature. This also suppresses the rise in the temperature of the coolant. Note that the first cooling control unit 51 is a so-called conventional cooling control.

[0039] The second cooling control unit 52 controls the output of the water pump 31 or the radiator fan 33 according to the coolant temperature detected by the coolant temperature sensor 23. The second cooling control unit 52 is executed on the premise that the first cooling control unit 51 is running.

[0040] More specifically, the second cooling control unit 52 increases the output of the water pump 31 when the coolant temperature detected by the coolant temperature sensor 23 is above a predetermined temperature while the vehicle is in motion. Alternatively, to determine if the vehicle is in motion, it may be considered to be in motion if the vehicle speed detected by the vehicle speed sensor is above a predetermined speed.

[0041] Here, when the ambient temperature is low, the coolant is sufficiently cooled in the radiator 32. Therefore, when controlling the flow rate of the coolant or the amount of air supplied to the radiator 32 according to the temperature of the coolant, the flow rate of the coolant decreases and the amount of air supplied to the radiator 32 also decreases according to the temperature of the coolant. However, the transaxle unit 21 generates more heat as the driving speed increases. For example, during high-speed operation when the ambient temperature is low, if the flow rate of the coolant is low and the amount of air supplied to the radiator 32 is low, the heat of the coolant may not be sufficiently removed, causing the temperature of the coolant to rise.

[0042] According to the first cooling control unit 51, when the vehicle is in motion and the coolant temperature is above a predetermined temperature, the output of the water pump 31 is increased. This increases the flow rate of the coolant and reduces the temperature of the coolant.

[0043] Furthermore, when the vehicle is stopped, the second cooling control unit 52 increases the output of the radiator fan 33 if the coolant temperature detected by the coolant temperature sensor 23 is above a predetermined temperature. Note that to determine whether the vehicle is stopped, if the vehicle speed detected by the vehicle speed sensor is below a predetermined speed, the vehicle may be considered stopped.

[0044] When the vehicle is stopped, the flow rate of the coolant is low, so even if the amount of coolant that exchanges heat with the coolant is increased, the heat exchange efficiency between the coolant and the coolant is poor. According to the second cooling control unit 52, when the vehicle is stopped and the coolant temperature is above a predetermined temperature, the output of the radiator fan 33 is increased. This reduces the temperature of the coolant and thus the temperature of the coolant.

[0045] The third cooling control unit 53 controls the output of the water pump 31 or the radiator fan 33 according to the air temperature detected by the air temperature sensor 36. The third cooling control unit 53 operates on the premise that the first cooling control unit 51 and the second cooling control unit 52 are running.

[0046] According to the third cooling control unit 53, the heat absorption and dissipation in the radiator 32 can be calculated, allowing for more accurate control of the cooling system 10.

[0047] [Cooling control] Using Figure 3, we will explain the flow of the second cooling control unit 52, which is an example of an embodiment.

[0048] In step S11, it is checked whether the vehicle is in motion. If the answer in step S11 is YES, proceed to step S12; otherwise, proceed to step S14.

[0049] In step S12, it is checked whether the coolant temperature detected by the coolant temperature sensor 23 is above a predetermined temperature. If the answer in step S12 is YES, the process proceeds to step S13; otherwise, the process proceeds to step S11. In step S13, the output of the water pump 31 is increased. This increases the flow rate of the coolant and reduces the temperature of the coolant.

[0050] In step S14, it is checked whether the coolant temperature detected by the coolant temperature sensor 23 is above a predetermined temperature. If the answer in step S14 is YES, the process proceeds to step S15; otherwise, the process proceeds to step S11. In step S15, the output of the radiator fan 33 is increased. This reduces the temperature of the coolant water and thus the temperature of the coolant.

[0051] It should be noted that the present invention is not limited to the embodiments and their modifications described above, and various changes and improvements are possible within the scope of the claims of this application. [Explanation of symbols]

[0052] 10 Cooling system, 20 Cooling oil circuit, 21 Transaxle unit, 22 Oil cooler, 23 Cooling oil temperature sensor, 30 Cooling water circuit, 31 Water pump, 32 Radiator, 33 Radiator fan, 35 Cooling water temperature sensor, 36 Air temperature sensor, 50 Control device, 51 First cooling section, 52 Second cooling section, 53 Third cooling section

Claims

1. It comprises a cooling oil circuit for circulating cooling oil to cool the vehicle's drive unit, and a cooling water circuit for circulating cooling water to cool the cooling oil, The cooling water circuit comprises an oil cooler that exchanges heat with the cooling oil, a water pump that adjusts the flow rate of the cooling water, a radiator that cools the cooling water, a radiator fan that adjusts the amount of air supplied to the radiator, and a control device that controls the output of the water pump or the output of the radiator fan. The control device controls the output of the water pump or the radiator fan according to the temperature of the coolant, and also controls the output of the water pump or the radiator fan according to the temperature of the coolant. Vehicle cooling system.

2. The control device increases the output of the water pump when the vehicle is in motion and the temperature of the coolant is above a predetermined temperature. The vehicle cooling system according to claim 1.

3. The control device increases the output of the radiator fan when the vehicle is stopped and the temperature of the coolant is above a predetermined temperature. The vehicle cooling system according to claim 1.

4. The control device controls the output of the water pump or the radiator fan according to the air temperature of the radiator fan. A vehicle cooling system according to any one of claims 1 to 3.

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