JP7292801B2 - Cooling system controller - Google Patents

Description

The present invention relates to a cooling system control device for controlling a cooling system of a vehicle.

2. Description of the Related Art Conventionally, a hybrid vehicle equipped with an engine and a drive motor as a drive source for running is known.

A hybrid vehicle is equipped with a PCU (Power Control Unit) that incorporates an inverter and a microcomputer (microcontroller unit) for driving a drive motor. Also, the hybrid vehicle is provided with an engine cooling system for cooling the engine and an HV cooling system for cooling the transaxle and the PCU. Cooling of the PCU by the HV cooling system can prevent thermal destruction of electronic components inside the PCU.

When the ignition switch is turned off, the water pumps that circulate cooling water in the engine cooling system and the HV cooling system are stopped, and the flow of cooling water in each cooling system is stopped. Therefore, during dead soak, the heat of each cooling system moves upward, and the temperature of the atmosphere in the engine compartment also affects the temperature of the cooling water in the upper flow passage of each cooling system.

For example, in Patent Document 1, in order to prevent high-temperature cooling water from being supplied to the inverter, power is supplied to the inverter if the temperature of the cooling water is equal to or higher than a predetermined temperature when the ignition switch is turned on. It has been proposed to start the water pump before starting the However, if the cooling water has become abnormally hot due to dead soak, there is a possibility that the abnormally high temperature of the cooling water will not be resolved immediately even if the water pump is driven.

Japanese Patent No. 6090465

In a configuration in which the PCU is arranged above the transaxle, a heat pool state occurs in which high-temperature cooling water accumulates in the flow path inside the PCU during dead soak. When the ignition switch is turned on in a situation where the temperature of the cooling water in the PCU exceeds a predetermined allowable water temperature due to heat buildup, the PCU protection function is activated and the driving of the hybrid vehicle is restricted. reduced mobility. In addition, an increase in the internal temperature of the PCU due to heat accumulation may adversely affect the durability and reliability of electronic components (heat damage).

SUMMARY OF THE INVENTION An object of the present invention is to provide a cooling system control device capable of suppressing accumulation of heat due to high-temperature cooling water in a power control unit.

In order to achieve the above object, the cooling system control device according to the present invention comprises a drive transmission unit containing a motor, and a power control unit arranged above the drive transmission unit and containing a circuit for driving the motor. , a cooling system for circulating cooling water to a drive transmission unit and a power control unit by operation of an electric water pump, the cooling system control device mounted on the vehicle, wherein the power control unit is installed while the ignition switch of the vehicle is off. Inference means for estimating whether or not the temperature of the cooling water inside will rise above the allowable water temperature, and if the estimating means infers that the temperature of the cooling water will rise above the allowable water temperature, a predetermined time after the ignition switch is turned off. , and pump actuating means for actuating the electric water pump.

According to this configuration, when the temperature of the cooling water in the power control unit is estimated to rise above the allowable water temperature while the ignition switch is off, the electric water pump operates for a predetermined time after the ignition switch is off. By operating the electric water pump, the cooling water flows through the power control unit, so it is possible to suppress the accumulation of heat due to the high-temperature cooling water in the power control unit. Therefore, when the ignition switch is turned on, activation of the power control unit protection function can be suppressed. As a result, it is possible to prevent restrictions on the running of the vehicle, and to avoid deterioration of drivability due to the restrictions. In addition, it is possible to suppress an increase in the internal temperature of the power control unit due to heat buildup, thereby preventing heat damage to the power control unit.

The estimating means determines whether or not the temperature of the cooling water rises above the allowable water temperature based on at least one temperature of the internal temperature of the power control unit, the temperature of the motor of the drive transmission unit, and the air temperature outside the vehicle. You can guess.

The pump operating means variably sets the operating time (predetermined time) of the electric water pump according to at least one of the internal temperature of the power control unit, the temperature of the motor of the drive transmission unit, and the air temperature outside the vehicle. You may As a result, it is possible to more accurately prevent the temperature of the cooling water in the power control unit from rising above the allowable water temperature.

According to the present invention, it is possible to suppress the accumulation of heat due to high-temperature cooling water in the power control unit. As a result, it is possible to prevent the driving of the vehicle from being restricted by the protection function of the power control unit, thereby avoiding the deterioration of drivability due to the restriction. Also, heat damage to the power control unit can be prevented.

1 is a side view showing the configuration of a drive system of a vehicle; FIG. 1 is a diagram schematically showing the configuration of an HV cooling system of a vehicle; FIG. 1 is a block diagram showing the configuration (electrical configuration) of a control system of a vehicle; FIG. It is a figure which shows the content of water pump actuation control. 5 is a graph showing an example of temporal changes in the temperature of cooling water in the PCU;

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Drive system>
FIG. 1 is a side view showing the configuration of a vehicle drive system.

The vehicle is, for example, a hybrid vehicle equipped with an engine and a motor generator 1 (see FIG. 3) that is a drive source for running.

Motor generator 1 functions as an electric motor and a generator, and is composed of, for example, a DC brushless motor. The motor generator 1 is accommodated in the unit case 2 together with a differential gear, and constitutes a transaxle 3 that transmits power to drive wheels. The transaxle 3 is arranged in the engine compartment of the vehicle.

The vehicle is also equipped with a PCU (Power Control Unit) 4 for controlling the motor generator 1 . The PCU 4 incorporates an inverter for driving the motor generator 1 and the like. PCU 4 is arranged above transaxle 3 .

<HV cooling system>
FIG. 2 is a diagram schematically showing the configuration of the HV cooling system 11 of the vehicle.

The vehicle is provided with an engine cooling system that cools the engine, and an HV cooling system 11 that cools the transaxle 3 and the PCU 4 .

The HV cooling system 11 includes a water pump (W/P) 12 and an HV radiator 13 . The water pump 12 is an electric water pump and can operate even when the engine is stopped. In the HV cooling system 11, when the water pump 12 operates, the cooling water sent from the water pump 12 flows through the HV radiator 13, the PCU 4 and the transaxle (T/A) 3 in this order.

Specifically, the HV cooling system 11 includes a circulation path 14 through which cooling water flows. The circulation path 14 has one end connected to an inlet 15 of the HV radiator 13, an intermediate portion passing through an oil cooler (O/C) 16 of the transaxle 3 and the PCU 4, and the other end connected to an outlet 17 of the HV radiator 13. It is connected to the.

The water pump 12 is interposed between the oil cooler 16 and the inlet 15 of the HV radiator 13 in the circulation path 14 . A reserve tank (R/T) 18 that stores cooling water is interposed between the oil cooler 16 and the water pump 12 in the circulation path 14 .

By operating the water pump 12 , cooling water is sucked out from the reserve tank 18 and flows through the circulation path 14 . The cooling water flows into the HV radiator 13 from the inlet 15 and flows through the HV radiator 13 toward the outlet 17 . While the vehicle is running, running wind hits the HV radiator 13 , and heat is exchanged between the running wind and the cooling water flowing through the HV radiator 13 . When the vehicle is stopped, the HV radiator 13 is not exposed to running wind, so the radiator fan 19 arranged to face the HV radiator 13 is driven. As a result, air blown from outside the vehicle hits the HV radiator 13 , and heat is exchanged between the air blown and the cooling water flowing through the HV radiator 13 .

The cooling water flowing out from the outlet 17 of the HV radiator 13 to the circulation path 14 passes through the PCU 4 and the oil cooler 16 in order before returning to the reserve tank 18 . When the cooling water passes through the PCU 4, heat is exchanged between the cooling water and the PCU 4. In the oil cooler 16 , heat exchange takes place between cooling water passing through the oil cooler 16 and oil supplied from the transaxle 3 to the oil cooler 16 .

<Control system>
FIG. 3 is a block diagram showing the configuration (electrical configuration) of the control system of the vehicle.

The vehicle is equipped with an ECU (Electronic Control Unit) 21 including a microcomputer. Although only one ECU 21 is shown in FIG. 1, the vehicle is equipped with a plurality of ECUs to control each part. A plurality of ECUs including the ECU 21 are connected so as to be capable of two-way communication using a CAN (Controller Area Network) communication protocol.

Various sensors required for control are connected to the ECU 21 . As an example, the ECU 21 includes an MG temperature sensor 22 for detecting the temperature of the motor generator 1 (hereinafter referred to as "MG temperature") TM, and a temperature of the PCU 4 (hereinafter referred to as "PCU temperature") TH. A PCU temperature sensor 23 is connected to an outside air temperature sensor 24 that detects the outside air temperature (outside air temperature) TA of the vehicle.

The ECU 21 controls the driving of the motor generator 1 via the PCU 4 based on commands and the like transmitted from other ECUs. The ECU 21 also controls the driving of the water pump 12 and the radiator fan 19 based on the MG temperature TM, the PCU temperature TH, the outside air temperature TA, and the like.

<Water pump operation control>
FIG. 4 is a diagram showing the contents of the water pump operation control.

While the ignition switch of the vehicle is turned on, the ECU 21 repeatedly acquires the MG temperature TM, the PCU temperature TH and the outside air temperature TA at predetermined intervals. When the ignition switch is turned off, the ECU 21 executes water pump operation control. In the water pump operation control, based on the last detected MG temperature TM, PCU temperature TH and outside air temperature TA, the IG is maintained even after the ignition switch is turned off (hereinafter referred to as "IG off") according to the procedure described below. It is determined whether or not to continue the operation of the water pump 12 and the radiator fan 19 from before turning off. Further, when it is determined to continue the operation of the water pump 12 and the radiator fan 19, the duration is determined.

It should be noted that each temperature value shown below is merely an example, and may be appropriately changed and set.

(1) It is determined whether the PCU temperature TH is less than 55°C, 55°C or more and less than 60°C, or 60°C or more.

(1-1) When the PCU temperature TH is less than 55° C., it is determined not to continue the operation of the water pump 12 and the radiator fan 19 after the IG is turned off, and the water pump 12 and the radiator fan 19 are stopped.

(1-2) When the PCU temperature TH is 55° C. or more and less than 60° C., it is determined whether the MG temperature TM is less than 100° C., 100° C. or more and less than 120° C., or 120° C. or more.

(1-2-1) When the MG temperature TM is less than 100° C., it is determined not to continue the operation of the water pump 12 and the radiator fan 19 after the IG is turned off, and the water pump 12 and the radiator fan 19 are stopped.

(1-2-2) When the MG temperature TM is 100° C. or more and less than 120° C., it is determined whether the outside air temperature TA is less than 30° C. or 30° C. or more.

(1-2-2-1) If the outside air temperature TA is less than 30° C., it is determined to continue operating the water pump 12 for 30 seconds after the IG is turned off. The operation of the water pump 12 is continued for 30 seconds after the IG is turned off.

(1-2-2-2) When the outside air temperature TA is 30° C. or higher, it is determined that both the water pump 12 and the radiator fan 19 continue to operate for 30 seconds after the IG is turned off. The operation of the water pump 12 and the radiator fan 19 is continued for 30 seconds after the IG is turned off.

(1-2-3) When the MG temperature TM is 120°C or higher, it is determined whether the outside air temperature TA is lower than 30°C or higher than 30°C.

(1-2-3-1) If the outside air temperature TA is less than 30° C., it is determined that the water pump 12 should continue to operate for 60 seconds after the IG is turned off. The operation of the water pump 12 is continued for 60 seconds after the IG is turned off.

(1-2-3-2) When the outside air temperature TA is 30° C. or higher, it is determined that both the water pump 12 and the radiator fan 19 continue to operate for 60 seconds after the IG is turned off. The operation of the water pump 12 and the radiator fan 19 is continued for 60 seconds after the IG is turned off.

(1-3) When the PCU temperature TH is 60° C. or more, it is determined whether the MG temperature TM is less than 120° C. or 120° C. or more.

(1-3-1) If the MG temperature TM is less than 120.degree. C., it is determined whether the outside air temperature TA is less than 30.degree.

(1-3-1-1) If the outside air temperature TA is less than 30° C., it is determined to continue operating the water pump 12 for 60 seconds after the IG is turned off. The operation of the water pump 12 is continued for 60 seconds after the IG is turned off.

(1-3-1-2) If the outside air temperature TA is 30° C. or higher, it is determined that both the water pump 12 and the radiator fan 19 continue to operate for 60 seconds after the IG is turned off. The operation of the water pump 12 and the radiator fan 19 is continued for 60 seconds after the IG is turned off.

(1-3-2) When the MG temperature TM is 120°C or higher, it is determined whether the outside air temperature TA is lower than 30°C or higher than 30°C.

(1-3-2-1) If the outside air temperature TA is less than 30° C., it is determined to continue operating the water pump 12 for 90 seconds after the IG is turned off. The operation of the water pump 12 is continued for 90 seconds after the IG is turned off.

(1-3-2-2) When the outside air temperature TA is 30° C. or higher, it is determined that both the water pump 12 and the radiator fan 19 continue to operate for 90 seconds after the IG is turned off. The operation of the water pump 12 and the radiator fan 19 is continued for 90 seconds after the IG is turned off.

<Effect>
When the PCU temperature TH is 60° C. or more, or when the PCU temperature TH is 55° C. or more and less than 60° C. and the MG temperature TM is 100° C. or more, the water pump 12 is stopped after the IG is turned off. Then, as indicated by the two-dot chain line in FIG. 5, it is presumed that the temperature of the cooling water in the PCU 4 rises above the allowable water temperature while the IG is off. In this case, at least the operation of the water pump 12 continues even after the IG is turned off. The operation of the water pump 12 circulates the cooling water inside the PCU 4 , so that the heat generated by the high-temperature cooling water is prevented from accumulating inside the PCU 4 . As a result, the temperature of the cooling water in the PCU 4 is suppressed from rising above the allowable water temperature while the ignition switch is off, and as shown by the solid line in FIG. is maintained below the permissible water temperature.

For example, if the specification is such that the PCU protection function for protecting the PCU 4 is activated on condition that the temperature of the cooling water in the PCU 4 is equal to or higher than the allowable water temperature, the PCU is protected when the ignition switch is turned on. You can suppress the activation of the function. As a result, it is possible to prevent the vehicle from being restricted by the PCU protection function, thereby avoiding the deterioration of drivability due to the restriction. Moreover, it is possible to suppress an increase in the internal temperature of the PCU 4 after the IG is turned off, and to suppress heat damage to the PCU 4 .

Further, when the operation of the water pump 12 is continued after the IG is turned off and the outside air temperature TA is 30° C. or higher, the temperature drop in the engine compartment of the vehicle is small, so the operation of the water pump 12 is small. Even if this is continued, there is a possibility that heat damage will reach the PCU 4 . Therefore, in such a case, the operation of the water pump 12 and the operation of the radiator fan 19 are continued. As a result, the temperature of the cooling water can be lowered, and heat damage to the PCU 4 can be effectively suppressed.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, in the above-described embodiment, it is estimated whether or not the temperature of the cooling water in the PCU 4 rises above the allowable water temperature while the IG is turned off, that is, it is determined whether or not to continue the operation of the water pump 12 after the IG is turned off. , both the MG temperature TM and the PCU temperature TH are used, but only one of them may be used.

Further, although the operation of the water pump 12 is continued from before the IG is turned off to after the IG is turned off, the water pump 12 is temporarily stopped in response to the IG being turned off, and then the water pump 12 is operated at a predetermined timing. may be resumed. The radiator fan 19 is also the same. However, it is preferable to continue the operation of the water pump 12 and the radiator fan 19. In this case, it is possible to further reduce the possibility that the temperature of the cooling water in the PCU 4 rises above the allowable water temperature.

In addition, various design changes can be made to the above configuration within the scope of the matters described in the claims.

1: Motor generator (motor)
3: Transaxle (drive transmission unit)
11: HV cooling system (cooling system)
12: Water pump (electric water pump)
21: ECU (cooling system control device, estimation means, pump operation means)

Claims (3)

a drive transmission unit containing a motor; a power control unit disposed above the drive transmission unit and containing a circuit for driving the motor; and an electric water pump operating to control the drive transmission unit and the power control unit. A cooling system control device mounted on a vehicle comprising a cooling system that circulates cooling water in
Whether the temperature of cooling water in the power control unit rises above an allowable water temperature while the ignition switch of the vehicle is off, based on the internal temperature of the power control unit and the temperature of the motor of the drive transmission unit. a guessing means for guessing
pump operating means for operating the electric water pump for a predetermined time after the ignition switch is turned off when the estimation means estimates that the cooling water temperature in the power control unit rises above the allowable water temperature. , cooling system controller. The pump operating means variably sets the predetermined time according to at least one temperature of an internal temperature of the power control unit, a temperature of the motor of the drive transmission unit, and an air temperature outside the vehicle. Item 1. The cooling system control device according to item 1. The cooling system includes a radiator through which cooling water flows and a radiator fan that supplies air to the radiator,
When the estimation means estimates that the temperature of cooling water in the power control unit rises above the allowable water temperature, the radiator fan is operated after the ignition switch is turned off according to the temperature outside the vehicle. 3. A cooling system controller according to claim 1 or 2, further comprising fan operating means.

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