JP7206757B2 - Cooling system for vehicle and control method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle cooling system and its control method, and more particularly to a vehicle cooling system that achieves both improved fuel efficiency and maintenance of durability performance, and its control method.

As a vehicle cooling system, the operation of the electric water pump is controlled based on the water temperature and the oil temperature in a first control mode in which the engine output according to the engine speed and the fuel injection amount is equal to or less than a threshold value, and in the second control mode. A device has been proposed that controls the operation of an electric water pump based on the output of the engine in the control mode (see, for example, Patent Document 1). The device described in Patent Document 1 switches the control mode of the operation of the electric water pump based on the output of the engine, thereby reducing the mechanical loss of the engine and preventing deterioration (durability) caused by excessive temperature rise of the cooling system. deterioration) is prevented.

JP 2012-067718 A

In a cooling system for a vehicle, a flow control device such as a thermostat adjusts the flow rate of cooling water flowing through a flow path passing through a radiator and a flow path bypassing the radiator based on the temperature of the cooling water. . Similarly, in a vehicle cooling system, the number of rotations of a cooling fan that blows cooling air to the engine is adjusted based on the temperature of the cooling water and the temperature of the air after passing through the radiator.

If the target temperature of the flow control device or the cooling fan is increased in order to improve the fuel efficiency when the engine output is low, in the cooling system described in Patent Document 1, the oil temperature increases when the engine output is high. Decreases durability. On the other hand, if the target temperature of the flow control device and the cooling fan is lowered in order to maintain durability when the engine output is high, the cooling system described in Patent Document 1 reduces the oil temperature when the engine output is low. fuel consumption worsens as friction increases.

An object of the present disclosure is to provide a vehicle cooling system that achieves both improved fuel efficiency and maintenance of durability, and a control method thereof.

According to one aspect of the present invention, there is provided a vehicle cooling system for achieving the above object, comprising: a radiator passage having a radiator through which cooling water for cooling a driving source passes; a bypass passage bypassing the radiator; A cooling system for a vehicle comprising: a flow rate adjusting device that adjusts the flow rate of cooling water flowing through each of the radiator flow path and the bypass flow path; and a cooling fan that blows cooling air to the driving source, wherein the driving source is A parameter acquisition device that acquires a parameter related to the amount of cooling loss; A plurality of control modes, a fuel efficiency priority mode having a first target water temperature as a value and a durability priority mode having a second target water temperature lower than the first target water temperature, are set, and the plurality of control modes are selected. A threshold loss amount used for is set in advance, and the control device selects the fuel consumption priority mode when the cooling loss amount calculated according to the parameter acquired by the parameter acquisition device is less than the threshold loss amount, The durability mode is selected when the cooling loss mass is greater than or equal to the threshold loss amount, and the flow rate of the cooling water flowing through the radiator flow path by the flow control device according to one of the selected plurality of control modes. and controlling the number of revolutions of the cooling fan.

According to one aspect of the present invention, there is provided a vehicle cooling system control method that achieves the above object. A control method for a cooling system for a vehicle, which adjusts the flow rate of cooling water flowing through each of the bypass flow paths and adjusts the rotation speed of a cooling fan that blows cooling air to the drive source, wherein the cooling loss of the drive source obtaining a parameter related to the amount of cooling water, estimating the cooling loss amount based on the obtained parameter, and setting the first target water temperature as a target value of the cooling water temperature when the estimated cooling loss amount is less than the threshold loss amount selects a fuel efficiency priority mode having a fuel consumption priority mode, selects a durability priority mode having a second target water temperature lower than the first target water temperature when the cooling loss amount is equal to or greater than the threshold loss amount , and selects a plurality of control modes According to one of the above, the flow rate adjusting device adjusts the flow rate of cooling water flowing through the radiator channel and the rotation speed of the cooling fan.

According to one aspect of the present invention, it is possible to achieve both improvement in fuel efficiency and maintenance of durability.

1 is a configuration diagram illustrating a first embodiment of a vehicle cooling system, showing a state in which cooling water flows through a radiator flow path; FIG. 1 is a configuration diagram illustrating a first embodiment of a vehicle cooling system, showing a state in which cooling water flows through a bypass flow path; FIG. 2 is a block diagram illustrating the controller of FIG. 1; FIG. FIG. 4 is an explanatory diagram illustrating determination map data of FIG. 3 ; FIG. FIG. 3 is a relationship diagram illustrating the relationship between the water temperature and the lift amount of the lifter in the first embodiment of the vehicle cooling system. FIG. 2 is a relationship diagram illustrating the relationship between the water temperature and the rotation speed of the cooling fan in the first embodiment of the vehicle cooling system. 1 is a flow diagram illustrating a method of controlling a cooling system for a vehicle; FIG. FIG. 7 is an explanatory diagram illustrating determination map data in the second embodiment of the vehicle cooling system; FIG. 7 is a relationship diagram illustrating the relationship between the water temperature and the lift amount of the lifter in the second embodiment of the vehicle cooling system. FIG. 7 is a relationship diagram illustrating the relationship between the water temperature and the rotation speed of the cooling fan in the second embodiment of the vehicle cooling system. FIG. 11 is an explanatory diagram illustrating determination map data in the vehicle cooling system according to the third embodiment;

An embodiment of a vehicle cooling system 10 will be described below with reference to the drawings. In the drawing, W1 indicates the cooling water, and the state in which the cooling water W1 is flowing in the flow path is indicated by a thick line to distinguish it from the state in which the cooling water W1 is stopped.

As illustrated in FIGS. 1 to 3, a vehicle cooling system 10 of the first embodiment is a system for cooling an engine 1, which is a drive source. As a drive source to be cooled by the cooling system 10, a motor generator is exemplified in addition to the engine 1. FIG.

The cooling system 10 includes a water pump 11 , a water jacket 12 , a radiator 13 , a flow control device 14 and a cooling fan 15 , as well as a radiator channel 16 and a bypass channel 17 . The cooling system 10 also includes an accelerator opening sensor 20 and a rotation speed sensor 21 functioning as parameter acquisition devices, a water temperature sensor 22 functioning as a temperature acquisition device, and a control device 23 connected to these sensors.

The water pump 11 is connected via a power transmission mechanism 4 such as an endless belt or chain to a crankshaft 3 that obtains rotational power by combustion of fuel injected from the injector 2 of the engine 1, and is output from the engine 1. It is driven by rotational power. As the water pump 11 , in addition to a pump driven by rotational power from the engine 1 , an electric pump driven by driving power from an electric motor is also exemplified.

The water jacket 12 is formed inside the engine 1 so as to surround the cylinder 5 . As the cooling water W1 flows inside the water jacket 12, the cylinder 5 is cooled, and part of the heat generated by the combustion of the fuel injected from the injector 2 is lost.

The radiator 13 is arranged on the front side of the engine 1, which is a driving source. The radiator 13 uses the vehicle speed wind and the cooling wind from the subsequent cooling fan 15 to cool the cooling water W1 passing therethrough.

The flow control device 14 is an electrically controlled thermostat, and has a lifter 14a consisting of a cylinder and a piston, a thermal expansion body 14b filled inside the cylinder, and an electric heater 14c installed inside the piston. . The thermal expansion body 14b has a property of melting and expanding in volume as the water temperature Tx of the cooling water W1 rises, and solidifying and shrinking in volume as the temperature drops. Thermowax is exemplified as the thermal expansion body 14b. The flow control device 14 is configured so that the thermal expansion body 14b expands as the temperature of the thermal expansion body 14b rises due to the electric heat of the electric heater 14c, and forcibly opens the passage from the water jacket 12 to the radiator 13. be done.

When the water temperature Tx is lower than the melting temperature of the thermal expansion body 14b, the flow control device 14 blocks the passage from the water jacket 12 to the radiator 13 and bypasses the radiator 13 from the water jacket 12 to the water pump 11. open the aisle. On the other hand, when the water temperature Tx is higher than the melting temperature of the thermal expansion body 14b, the flow control device 14 pushes the piston axially out of the cylinder due to the expansion of the thermal expansion body 14b, and the cylinder moves away from the piston. , the lifter 14a extends. The extension of the lifter 14 a opens the passage from the water jacket 12 to the radiator 13 and blocks the passage from the water jacket 12 to the water pump 11 bypassing the radiator 13 . The flow control device 14 opens both passages when the lifter 14a is not fully extended.

The cooling fan 15 is a fan that is interposed between the radiator 13 and the engine 1, is connected to the crankshaft 3 and drives, and blows cooling air to the engine 1 behind. Cooling fan 15 is connected to crankshaft 3 via fan clutch 18 . The fan clutch 18 is an electrically controlled viscous clutch, and is configured to be able to adjust the rotational speed of the cooling fan 15 by means of a slip ratio. The cooling fan 15 may be a fan that can blow cooling air to the engine 1, which is a drive source, and that can rotate freely. is also exemplified.

The radiator flow path 16 is a flow path in which the water pump 11, the water jacket 12, and the radiator 13 are connected by pipes in an annular manner with respect to the flow of the cooling water W1. is a flow path that is cooled by heat exchange at .

The bypass flow path 17 is a flow path that traverses the midpoint of the radiator flow path 16 so as to bypass the radiator 13, and is annularly connected to the water pump 11 and the water jacket 12 by piping with respect to the flow of the cooling water W1. . The bypass flow path 17 is a flow path in which the cooling water W1 flowing through the flow path is prevented from passing through the radiator 13, so that the cooling water W1 is not cooled and the water temperature Tx is maintained.

The accelerator opening sensor 20 is a sensor that functions as part of a parameter acquisition device, and is a device for acquiring the fuel injection amount Qx as a parameter related to the cooling loss amount Qwx of the engine 1 . As the parameter acquiring device, any parameter for acquiring the fuel injection amount Qx can be acquired, and a sensor for acquiring the opening of a throttle valve (not shown) may be used instead of the accelerator opening sensor 20 .

The rotation speed sensor 21 is a sensor that functions as a parameter acquisition device, and is a device that acquires the engine rotation speed Nex as a parameter related to the cooling loss amount Qwx of the engine 1 . The rotation speed sensor 21 is not limited to a configuration that detects the rotation speed of the crankshaft 3 and acquires the engine rotation speed Nex as long as it can acquire the engine rotation speed Nex.

The water temperature sensor 22 is a sensor that functions as a temperature acquisition device, and is a sensor that acquires the water temperature Tx after passing through the water jacket 12 . The temperature sensor 22 only needs to be able to acquire the water temperature Tx after passing through the water jacket 12, and may be interposed between the radiator 13 and the outlet of the water jacket 12 with respect to the flow of the cooling water W1.

As exemplified in FIG. 3, the control device 23 includes a CPU that performs various types of information processing, an internal storage device that can read and write programs and information processing results used for performing the various types of information processing, and various interfaces. hardware. The control device 23 is electrically connected to the accelerator opening sensor 20, the rotation speed sensor 21, the water temperature sensor 22, the electric heater 14c, and the fan clutch 18. Also, the control device 23 is electrically connected to the injector 2 and performs control for adjusting the fuel injection amount injected from the injector 2 . As described above, the control device 23 is exemplified as a device that functions as an ECU (engine control unit) that controls the engine 1, but it can also be used as a device that obtains information on the fuel injection amount Qx from the ECU as a separate entity from the ECU. good.

The control device 23 has an injection amount acquisition section 24, a loss amount estimation section 25, a mode selection section 26, and a control section 27 as functional elements. Each functional element is stored as a program in the internal storage device and executed by the CPU at appropriate times. Note that each functional element may be configured by a programmable controller (PLC) or an electric circuit that functions independently of the program.

The injection amount acquisition unit 24 functions as a part of the parameter acquisition device, receives the accelerator opening Ax acquired by the accelerator opening sensor 20, and calculates the cooling loss amount Qwx of the engine 1 based on the accelerator opening Ax. It is a functional element that calculates the fuel injection amount Qx as a parameter related to . The injection amount acquisition unit 24 is not limited to the configuration that calculates the fuel injection amount Qx based on the accelerator opening Ax, and may be configured to calculate the fuel injection amount Qx based on the opening of the throttle valve.

The loss amount estimator 25 receives the engine speed Nex and the fuel injection amount Qx, estimates the cooling loss amount Qwx of the engine 1 based on the parameters related to the cooling loss amount Qwx, and calculates the estimated cooling loss amount. It is a functional element that outputs Qwx to the mode selection unit 26 .

As illustrated in FIG. 4, the loss amount estimator 25 refers to the determination map data D1 based on the fuel injection amount Qx and the engine speed Nex to calculate the current cooling loss amount Qwx of the engine 1. is an element.

In the present disclosure, the cooling loss amount Qwx indicates the amount of energy lost through the cooling system 10 (lost due to cooling loss) out of the energy generated by the engine 1 . The energy obtained by burning the fuel injection amount Qx in the engine 1 is lost due to exhaust loss, mechanical loss, and pumping loss in addition to cooling loss. The cooling loss amount Qwx corresponds to the rate of change for each engine output calculated based on the fuel injection amount Qx and the engine speed Nex when the energy obtained by burning the injected fuel is assumed to be 100%. estimated by

The cooling loss amount Qwx has a positive correlation with the engine output, increases as the engine output increases, and decreases as the engine output decreases. The cooling loss amount Qwx is estimated by obtaining the ratio of the energy lost due to the cooling loss to the energy obtained by burning the injected fuel through experiments and tests for each engine output.

The determination map data D1 is map data in which the correlation between the cooling loss amount Qwx determined for each engine output and the parameters related to the cooling loss amount Qwx is set. Specifically, the determination map data D1 is map data in which the correlation between the cooling loss amount Qwx, the fuel injection amount Qx, and the engine output corresponding to the engine speed Nex is set, and is created in advance through experiments and tests. be done.

The mode selection unit 26 receives the cooling loss amount Qwx estimated by the loss amount estimation unit 25, compares the cooling loss amount Qwx with a preset threshold loss amount Qw1, and determines that the cooling loss amount Qwx is the threshold value. It is a functional element that selects the fuel consumption priority mode M1 when the cooling loss amount Qwx is less than the loss amount Qw1, and selects the durability priority mode M2 when the cooling loss amount Qwx is equal to or greater than the threshold loss amount Qw1. In addition, the mode selection unit 26 compares the water temperature Tx acquired by the water temperature sensor 22 when the fuel efficiency priority mode M1 is selected with a preset threshold temperature Ta, and when the water temperature Tx is equal to or lower than the threshold temperature Ta, It is also a functional element that maintains the fuel efficiency priority mode M1 and selects the durability priority mode M2 when the water temperature Tx is higher than the threshold temperature Ta.

The threshold loss amount Qw1 is a threshold for switching the control mode of the cooling system 10 . The threshold loss amount Qw1 selects the fuel efficiency priority mode M1 when the cooling loss amount Qwx is small and the oil temperature can be raised, and selects the durability priority mode M2 when the cooling loss amount Qwx is large and the oil temperature cannot be raised. is the threshold for The threshold loss amount Qw1 can be appropriately set through tests and experiments.

As illustrated in FIG. 5 , the threshold temperature Ta is a threshold for switching the control mode of the cooling system 10 . The threshold temperature Ta is a numerical value that can prevent the water temperature Tx from becoming excessively high in cooling according to the fuel consumption priority mode M1. The temperature is set to be higher than the temperature of the water flowing through the flow path 16 . In other words, the threshold temperature Ta is a numerical value that can determine a state in which the water temperature Tx cannot be maintained or lowered in the fuel efficiency priority mode M1. The threshold temperature Ta can be appropriately set through tests and experiments.

The fuel consumption priority mode M1 is a control mode in which a first target water temperature T1 lower than the threshold temperature Ta is set as the target value of the water temperature Tx. The fuel consumption priority mode M1 is a control mode in which the flow rate adjustment by the flow rate adjustment device 14 and the ventilation adjustment by the cooling fan 15 are performed so that the water temperature Tx becomes the first target water temperature T1. Specifically, in the fuel efficiency priority mode M1 of this embodiment, power supply to the electric heater 14c of the flow control device 14 is stopped, the flow control device 14 is operated based on the characteristics of the thermal expansion body 14b, and the fan clutch 18 cuts off the power transmission between the cooling fan 15 and the crankshaft 3 and turns the cooling fan 15 along with the vehicle speed wind.

The first target water temperature T1 is a water temperature that is lower than the threshold temperature Ta and that can maintain an oil water temperature that can reduce mechanical loss in the engine 1 . Specifically, the first target water temperature T1 is the temperature when the lifter 14a is fully extended with the electric heater 14c de-energized, and all the cooling water W1 after passing through the water jacket 12 flows into the radiator flow path 16. Set to water temperature. Note that T01 is the melting temperature of the thermal expansion body 14b and the temperature at which the lifter 14a starts lifting.

The durability priority mode M2 is a control mode in which the target value of the water temperature Tx is set to a second target water temperature T2 that is lower than the first target water temperature T1. The durability priority mode M2 is a control mode in which the flow rate is adjusted by the flow rate adjusting device 14 and the ventilation is adjusted by the cooling fan 15 so that the water temperature Tx becomes the second target water temperature T2. Specifically, the durability priority mode M2 of this embodiment lowers the water temperature Tx at which the lifter 14a starts to lift by energizing the electric heater 14c of the flow rate adjusting device 14, This is a control mode in which the power transmission with the crankshaft 3 is connected and the cooling fan 15 is rotated by the rotational power from the crankshaft 3 .

The second target water temperature T2 is a temperature lower than the first target water temperature T1, and is a water temperature that can avoid an excessively high temperature when the operating condition of the engine 1 is high load and high output. Specifically, the second target water temperature T2 is the water temperature when the lifter 14a is fully extended with the engine output reaching the maximum value, and all of the cooling water W1 after passing through the water jacket 12 flows into the radiator flow path 16. is set to Note that T02 is the temperature at which the thermal expansion member 14b reaches the melting temperature due to heating by the electric heater 14c and the lifter 14a starts lifting.

The water temperature Tx and the lift amount of the lifter 14a of the flow control device 14 are in a positive correlation. The first target water temperature T1, which is also the lift start temperature in the fuel efficiency priority mode M1, is lower than the threshold temperature Ta, and the lift start temperature in the durability priority mode M2 is higher than the second target water temperature T2. In addition, the lift amount increase rate in the fuel efficiency priority mode M1 is higher than the lift amount increase rate in the durability priority mode M2.

As illustrated in FIG. 6, in the fuel consumption priority mode M1, the water temperature Tx and the rotation speed Nfx of the cooling fan 15 are not correlated, and the rotation speed Nfx of the cooling fan 15 is correlated with the vehicle speed, that is, the speed of the vehicle. In the durability priority mode M2, the water temperature Tx and the rotational speed Nfx of the cooling fan 15 have a positive correlation. It is desirable that the maximum rotation speed of the rotation speed Nfx of the cooling fan 15 is set based on the second target water temperature T2.

The control unit 27 receives the water temperature Tx obtained by the water temperature sensor 22, and adjusts the energization of the electric heater 14c of the flow control device 14 and the slip ratio of the fan clutch 18 according to the control mode selected by the mode selection unit 26. It is a functional element that

The control method of the cooling system 10 of the present disclosure includes a method of selecting and switching the control mode for each predetermined cycle, and a method of controlling the rotation speed Nfx of the cooling fan 15 according to the control mode and the cooling water flowing through the radiator flow path 16 by the flow rate adjusting device 14. This is a method of adjusting the flow rate of W1.

As exemplified in FIG. 7, the method of selecting and switching control modes is a method that is repeatedly performed at predetermined intervals. The injection amount acquisition unit 24 acquires the fuel injection amount Qx based on the accelerator opening Ax acquired by the accelerator opening sensor 20, and the rotation speed sensor 21 acquires the engine rotation speed Nex (S110). Next, the cooling loss amount Qwx is estimated based on the fuel injection amount Qx and the engine speed Nex acquired by the loss amount estimating unit 25 (S120). Next, it is determined whether or not the cooling loss amount Qwx estimated by the mode selection unit 26 is smaller than the threshold loss amount Qw1 (S130).

If it is determined that the cooling loss amount Qwx is smaller than the threshold loss amount Qw1 (S130: YES), the mode selection unit 26 selects the fuel efficiency priority mode M1 (S140). Next, the water temperature sensor 22 acquires the water temperature Tx (S150). Next, it is determined whether or not the water temperature Tx acquired by the mode selection unit 26 is equal to or lower than the threshold temperature Ta (S160). When it is determined that the water temperature Tx is equal to or lower than the threshold temperature Ta (S160: YES), the fuel efficiency priority mode M1 is maintained and the process returns to the start.

On the other hand, if it is determined that the cooling loss amount Qwx is equal to or greater than the threshold loss amount Qw1 (S130: NO), or if it is determined that the water temperature Tx is higher than the threshold temperature Ta while the fuel consumption priority mode M1 is selected (S160: NO). , the mode selection unit 26 selects the durability priority mode M2 (S170), and returns to the start. Repeat the above to select the control mode.

Then, in parallel with the above method, the control unit 27 makes adjustments according to the selected control mode. Specifically, the control unit 27 compares the obtained water temperature Tx with the target water temperature (T1, T2) in the selected control mode, and determines the rotation speed Nfx of the cooling fan 15 and the radiator flow path by the flow rate adjusting device 14. The flow rate of cooling water W1 flowing through 16 is adjusted.

As described above, the cooling system 10 controls the rotation speed Nfx of the cooling fan 15 and the flow rate of the cooling water W1 flowing through the radiator flow path 16 by the flow control device 14 according to the control mode selected based on the cooling loss amount Qwx of the engine 1. adjust the In other words, the cooling system 10 can perform cooling according to the cooling loss amount Qwx that changes depending on the operating conditions of the engine 1 .

Specifically, in a situation where the cooling loss amount Qwx in the operating state of the engine 1 is small, the cooling system 10 sets the control mode to the fuel consumption priority mode M1 so that the flow rate adjusting device 14 causes the water temperature Tx to reach the first target water temperature T1. As a result, the mechanical loss can be reduced by increasing the oil temperature. Moreover, the drive loss for driving the cooling fan 15 can also be reduced.

On the other hand, the cooling system 10 sets the control mode to the durability priority mode M2 in a situation where the cooling loss amount Qwx in the operating state of the engine 1 is large. It is possible to prevent the water temperature from becoming T2 and the oil water temperature from reaching an excessively high temperature. Mechanical loss can be reduced by increasing the oil temperature.

As described above, according to the cooling system 10, by performing cooling according to different control modes based on the cooling loss amount Qwx of the engine 1, it is possible to achieve both improvement in fuel efficiency and maintenance of durability. can.

By selecting the control mode based on the cooling loss amount Qwx of the engine 1, the cooling system 10 can select the control mode according to the cooling-related conditions among the operating conditions of the engine 1. FIG. As a result, high-precision cooling, that is, cooling that is neither excessive nor deficient in consideration of improvement in fuel efficiency, can both improve fuel efficiency and maintain durability.

The cooling system 10 adjusts the flow rate of the cooling water W1 flowing through the radiator flow path 16 and the rotation speed Nfx of the cooling fan 15 by the flow control device 14 based on the high first target water temperature T1 as the target value in accordance with the fuel efficiency priority mode M1. Control to adjust. At this time, if the water temperature Tx becomes excessively high due to changes in the operating conditions of the engine 1 or the surrounding environment, the water temperature Tx can be prevented from becoming excessively high by switching from the fuel efficiency priority mode M1 to the durability priority mode M2. can be avoided. Thus, the cooling system 10 monitors the water temperature Tx in addition to the cooling loss amount Qwx, which is advantageous for maintaining durability.

As illustrated in FIGS. 8 to 10, the cooling system 10 of the second embodiment differs from the first embodiment in that it cools in three control modes. The mode selection unit 26 of the cooling system 10 of this embodiment receives the cooling loss amount Qwx estimated by the loss amount estimation unit 25, and compares the cooling loss amount Qwx with the threshold loss amount Qw1 and the threshold loss amount Qw2. Then, when the cooling loss amount Qwx is equal to or larger than the threshold loss amount Qw1 and smaller than the threshold loss amount Qw2, the high-speed fuel economy priority mode M3 is selected.

The threshold loss amount Qw2 is set to a loss amount larger than the threshold loss amount Qw1. The high-speed fuel consumption priority mode M3 has a third target water temperature T3 as the target value of the water temperature Tx. The third target water temperature T3 is set to a temperature lower than the first target water temperature T1 and higher than the second target water temperature T2.

Thus, the cooling system 10 may have three or more control modes depending on the operating conditions of the engine 1 . As the number of control modes increases, it becomes possible to respond to the operating conditions of the engine 1 more precisely, and highly accurate cooling can be achieved.

The rotational speed Nfx of the cooling fan 15 in the fuel efficiency priority mode M1 of the second embodiment has a positive correlation with the water temperature Tx, and the cooling fan 15 starts rotating in accordance with the lift start of the lifter 14a in the flow control device 14. configured to Further, the maximum rotation speed of the rotation speed Nfx of the cooling fan 15 is set based on the first target water temperature T1. In this manner, the cooling fan 15 may be configured to rotate based on the water temperature Tx in the fuel efficiency priority mode M1.

As illustrated in FIG. 11, the cooling system 10 of the third embodiment differs from the first embodiment in that the control mode is selected based on the constant fuel flow rate Qwy instead of the cooling loss amount Qwx.

The constant fuel flow rate Qwy is the sum total of the fuel injection amount Qx per unit time, and is a parameter that can be estimated according to the engine output calculated based on the engine speed Nex and the fuel injection amount Qx. As with the cooling loss amount Qwx, the constant fuel flow rate Qwy also has a positive correlation with the engine output, so it can be used for selecting the control mode instead of the cooling loss amount Qwx. A threshold flow rate Qw3 is exemplified as a threshold for selecting the control mode based on the constant fuel flow rate Qwy. The threshold flow rate Qw3 selects the fuel efficiency priority mode M1 when the constant fuel flow rate Qwy is small and the oil temperature can be increased, and selects the durability priority mode M2 when the constant fuel flow rate Qwy is high and the oil temperature cannot be increased. is the threshold. The threshold flow rate Qw3 can be appropriately set through tests and experiments.

As described above, the amount of heat dissipation required for cooling the engine 1 (the amount of heat dissipation required to bring the water temperature Tx to the target value) is exemplified as a parameter that can be used for selecting the control mode. However, it is desirable to use the cooling loss amount Qwx as the parameter because it enables the cooling by the cooling system 10 to be controlled with the highest accuracy.

In the above-described embodiment, an example in which the flow rate adjusting device 14 of the cooling system 10 is configured by an electrically controlled thermostat has been described. Any adjustable device may be used, and an electrically controlled three-way valve is also exemplified.

In addition, the configuration in which the flow rate adjusting device 14 is interposed between the water jacket 12 and the radiator 13 with respect to the flow of the cooling water W1 has been described as an example. You may make the structure interposed between.

1 engine (driving source)
10 Cooling system 13 Radiator 14 Flow control device 15 Cooling fan 16 Radiator flow path 17 Bypass flow path 20 Accelerator opening sensor 21 Revolution sensor 23 Control device Qwx Cooling loss amount M1 Fuel consumption priority mode M2 Durability priority mode

Claims (4)

A radiator channel having a radiator through which cooling water for cooling the driving source passes, a bypass channel bypassing the radiator, and a flow rate adjustment for adjusting the flow rate of the cooling water flowing through each of the radiator channel and the bypass channel. A cooling system for a vehicle comprising a device and a cooling fan that blows cooling air to the drive source,
a parameter acquisition device for acquiring a parameter related to a cooling loss amount of the drive source; and a control device connected to the parameter acquisition device, the flow rate adjustment device, and the cooling fan,
A plurality of control modes, a fuel efficiency priority mode having a first target water temperature as a target value for the coolant temperature and a durability priority mode having a second target water temperature lower than the first target water temperature, are set in the control device. and a threshold loss amount used for selecting the plurality of control modes is set in advance,
The control device selects the fuel efficiency priority mode when the cooling loss amount calculated according to the parameter acquired by the parameter acquisition device is less than the threshold loss amount, and the cooling loss mass exceeds the threshold loss amount. the durability priority mode is selected, and the flow rate adjusting device adjusts the flow rate of the cooling water flowing through the radiator flow path and the rotation speed of the cooling fan according to one of the plurality of selected control modes. A cooling system for a vehicle, characterized in that it performs control for cooling. A temperature acquisition device that is connected to the control device and acquires the temperature of the cooling water,
When the temperature of the cooling water obtained by the temperature obtaining device exceeds a threshold temperature set to a temperature higher than the first target water temperature when the control according to the fuel efficiency priority mode is being performed, 2. The cooling system for a vehicle according to claim 1 , wherein the control device controls selection of the durability mode. 3. The vehicle cooling system according to claim 1, wherein a constant fuel flow rate and a threshold flow rate calculated according to the parameters are used instead of the cooling loss amount and the threshold loss amount. The flow rate adjusting device adjusts the flow rate of cooling water flowing through each of a radiator channel having a radiator through which cooling water for cooling the drive source passes and a bypass channel bypassing the radiator, and cools the drive source. A control method for a vehicle cooling system that adjusts the rotation speed of a cooling fan that blows air,
Acquiring a parameter related to the amount of cooling loss of the drive source,
estimating the cooling loss amount based on the obtained parameters;
If the estimated cooling loss amount is less than the threshold loss amount, select the fuel efficiency priority mode having the first target water temperature as the target value of the cooling water temperature, and if the cooling loss amount is equal to or higher than the threshold loss amount, the above Selecting a durability priority mode with a second target water temperature that is lower than the first target water temperature ,
Control of a cooling system for a vehicle, characterized by adjusting the flow rate of cooling water flowing through the radiator flow path and the rotation speed of the cooling fan by the flow control device according to one of a plurality of selected control modes. Method.

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