JP7400261B2 - Vehicle electrical cooling system - Google Patents

Description

The disclosed technology relates to a cooling system that cools electrical devices that require cooling during operation, such as drive motors and inverters that are mounted on vehicles such as electric cars and hybrid cars.

The hybrid vehicle of Patent Document 1 is equipped with a cooling system that adjusts the temperature of the motor and inverter by circulating cooling water cooled by a radiator using an electric water pump. In this cooling system, if the temperature of the cooling water is below a predetermined threshold, it is determined that cooling is not necessary, and the water pump does not operate.

On the other hand, if the temperature of the cooling water is higher than the threshold, the water pump is operated at a predetermined target flow rate. At this time, the power consumption of the water pump is suppressed by switching the flow of cooling water to turbulent flow or laminar flow depending on the temperature of the cooling water.

Japanese Patent Application Publication No. 2005-224042

In the cooling system of Patent Document 1, when the temperature of the cooling water becomes excessively high, control is performed to increase the output of the water pump in order to increase the cooling capacity. If the temperature of the cooling water is not high, the cooling system is not used, such as by stopping the water pump, or even if it is used, its output is suppressed to the extent that its functionality is maintained.

However, in vehicles such as electric cars and hybrid cars that can be driven by electric power, due to structural constraints and usage conditions, even when the temperature of the coolant is low, the viscosity of the coolant increases. discovered that temperature abnormalities can occur in electrical equipment that is being cooled.

The main purpose of the technology disclosed therein is to provide an electrical cooling system that can stably protect electrical devices mounted on a vehicle from temperature abnormalities.

The disclosed technology relates to an electric cooling system installed in a vehicle capable of driving using electric power.

The electrical cooling system includes an electrical device to be cooled, an electric pump that circulates a coolant, and a cooling circuit in which the electrical device is arranged so as to be able to exchange heat with the coolant; A refrigerant temperature sensor that detects the temperature of the coolant circulating in a circuit, and a pump control device that controls the electric pump based on a detected value of the refrigerant temperature sensor. Then, when the refrigerant temperature sensor detects a temperature in a low temperature range including at least a sub-zero region of 0° C. or lower , the pump control device increases the output of the electric pump.

In other words, this electrical cooling system is equipped with a cooling circuit in which coolant is circulated by the operation of an electric pump, and an electrical device to be cooled is placed in the cooling circuit in a state where it can exchange heat with the coolant. It is located. This electric cooling system is configured such that the output of the electric pump is increased when the temperature of the coolant detected by the coolant temperature sensor is low.

Since vehicles may be driven at temperatures below freezing, antifreeze with high viscosity is used as the coolant. The viscosity of the coolant increases as the temperature of the coolant decreases. Therefore, the coolant at low temperature is subjected to large flow resistance. If the coolant is not circulating properly, the electrical equipment will not be able to exchange heat properly, even if the coolant temperature is low. As a result, temperature abnormalities may occur in electrical equipment.

In contrast, in this electric cooling system, the output of the electric pump is increased when the temperature of the coolant is low, so the flow of the coolant is promoted and the coolant can be circulated. Therefore, the electrical devices mounted on the vehicle can be stably protected from temperature abnormalities that occur at low temperatures (temperature abnormalities at low temperatures).

Particularly, the cooling circuit further includes a heat exchanger for cooling the coolant by heat exchange with outside air, the heat exchanger is arranged at the front side of the vehicle, and the electric device is arranged at the rear side of the vehicle. This is suitable if the device is located in

In this case, since the electrical device to be cooled is placed far away from the heat exchanger that cools the coolant, the cooling circuit becomes long. Therefore, the low-temperature coolant is subject to large flow resistance, making electrical devices even more susceptible to temperature abnormalities at low temperatures. On the other hand, in this electric cooling system, the output of the electric pump is increased, so that temperature abnormalities at low temperatures can be suppressed.

The electrical cooling system also includes a high-voltage battery that stores power for running, and a normal charging mode that charges the high-voltage battery by boosting the low voltage supplied from an external power source with a charger. and a route, and the electric device may be the charger.

Although details will be described later, the charger is fully operated for a long time when the vehicle is stopped. Therefore, the charger is prone to temperature abnormalities at low temperatures. On the other hand, in this electric cooling system, the output of the electric pump is increased, so that temperature abnormalities of the charger at low temperatures can be suppressed.

The vehicle further includes a drive motor that uses electric power from the high voltage battery to generate driving force for driving the vehicle, and a drive motor that is interposed between the drive motor and the high voltage battery to rotate the drive motor. and a converter that steps down the voltage of the high-voltage battery to a predetermined low voltage that supplies each of the charger and the inverter to enable its operation, the charger The drive motor, the inverter, and the converter are each cooled by the cooling circuit, and the drive motor, the inverter, the converter, and the charger are arranged in series in the cooling circuit. It may be said that there is.

When these electrical devices are placed in parallel in a cooling circuit, a branch point is created in the cooling circuit. Since the branched portion impedes the smooth flow of the coolant, bubbles are likely to occur in the coolant. When air bubbles are generated in the coolant, air pockets are formed in the cooling circuit. Air pockets cause insufficient cooling (heat spots). By placing the electrical device in series with the cooling circuit, the occurrence of such heat spots can be suppressed.

The converter, the inverter, the charger, and the drive motor may be arranged in this order downstream of the heat exchanger.

Generally, the amount of heat generated by these electrical devices is the least in the converter, followed by the inverter, charger, and drive motor in that order. By arranging electrical devices that generate less heat on the upstream side of the cooling circuit, each electrical device can be efficiently cooled and each of these electrical devices can be stably protected from temperature abnormalities.

The refrigerant temperature sensor may be disposed downstream of a portion of the cooling circuit that exchanges heat with the drive motor.

This position is where the temperature of the circulating coolant is highest. Therefore, based on the detected value of the refrigerant temperature sensor at that position, each electrical device arranged in the cooling circuit can be maintained at an appropriate temperature using only this sensor.

The vehicle further includes a quick charging path for charging the high voltage battery without going through the charger using a high voltage supplied from an external power source, and the output of the electric pump is transmitted through the quick charging path. The pump control device may increase the output of the electric pump in the low temperature range so that charging through the normal charging path is larger than charging through the normal charging path.

Chargers that are prone to temperature abnormalities at low temperatures will work during normal charging, but will not work during fast charging. Therefore, higher cooling performance is required for normal charging than for quick charging. On the other hand, in this electric cooling system, the output of the electric pump is set to be higher during normal charging than during quick charging. Therefore, during normal charging, the charger can be stably protected from abnormal temperatures at low temperatures, and during rapid charging, power consumption can be reduced.

Further, when charging through the normal charging path, the pump control device increases the output of the electric pump in the low temperature range, and when charging through the quick charging path, the pump control device increases the output of the electric pump in the low temperature range. The output of the electric pump may not be increased.

Also in this case, during normal charging, the charger can be stably protected from temperature abnormalities at low temperatures. Furthermore, since the output of the electric pump is not increased during rapid charging, power consumption can be further reduced.

According to the disclosed technology, it becomes possible to stably protect electrical devices mounted on a vehicle from temperature abnormalities.

1 is a schematic diagram showing the main configuration of an automobile in this embodiment. 1 is a wiring diagram of main electrical devices related to the drive of an automobile. FIG. 1 is a schematic configuration diagram of an electrical cooling system. FIG. 2 is a schematic side view of the electrical cooling system. FIG. 2 is a block diagram showing the relationship between a control device and its main related devices. It is a graph of control information showing the output of the electric pump with respect to the temperature of the coolant. It is a flow chart of control of an electric pump when driving a car. It is a flow chart of control of an electric pump when operation of a car is stopped. It is a flowchart (modification example) of control of an electric pump when operation of a car is stopped.

Hereinafter, embodiments of the disclosed technology will be described in detail based on the drawings. However, the following description is essentially just an example, and does not limit the present invention, its applications, or its uses.

<Vehicle>
FIG. 1 shows an automobile 1 (vehicle). In FIG. 1, the main configurations related to the disclosed technology are shown in a simplified manner. FIG. 2 shows a wiring diagram of the main electrical devices related to the drive of this automobile 1. FIG. 3 shows a schematic configuration diagram of the electric cooling system 40 in this automobile 1.

This automobile 1 is a so-called electric vehicle (Battery Electric Vehicle, BEV). A pair of front wheels 2F, 2F and a pair of rear wheels 2R, 2R are provided at the front and rear of the automobile 1, respectively. The automobile 1 travels by rotationally driving the pair of front wheels 2F, 2F using electric power. A vehicle compartment 1a for accommodating passengers is provided in the center of the automobile 1. A motor room 1b is provided in front of the vehicle interior 1a, and a trunk room 1c is provided in the rear of the vehicle interior 1a.

As shown in FIG. 1, this automobile 1 includes a radiator 2 (heat exchanger), a drive motor 3, an inverter 4, a converter 5, a high voltage battery 6, a low voltage battery 7, a charger 8, a charging plug 9, a control A device 10 and the like are installed.

The radiator 2 is arranged at the front end portion of the automobile 1 so as to extend in the vehicle width direction. The radiator 2 faces a front grill 11 covering the front end surface of the automobile 1. When the automobile 1 is running, outside air flows into the motor room 1b through the front grill 11. When the automobile 1 is stopped, outside air flows into the motor room 1b through the front grille 11 by the drive of a fan (not shown). The radiator 2 cools the coolant flowing through the radiator 2 by exchanging heat with the outside air. The radiator 2 constitutes a part of the electrical cooling system 40.

The drive motor 3 is arranged in the motor room 1b. The drive motor 3 generates the driving force for driving the automobile 1. The drive shaft of the drive motor 3 is connected to the left and right front wheels 2F, 2F via a reduction gear, a clutch, a drive shaft, etc. (not shown). The drive motor 3 is a permanent magnet type synchronous motor whose drive shaft rotates using three-phase alternating current.

High voltage battery 6 is a large secondary battery. The high-voltage battery 6 is arranged in the lower part of the automobile 1, from the passenger compartment 1a to the trunk room 1c. The high voltage battery 6 is also a high voltage DC power source, and is configured to be able to store electricity at a voltage of 300V or higher, for example. Electric power for driving the drive motor 3 is supplied by a high voltage battery 6.

The inverter 4 is a known device that performs power control. The inverter 4 and the drive motor 3 are arranged in the motor room 1b. The inverter 4 is interposed between the drive motor 3 and the high voltage battery 6 and controls the electric power supplied from the high voltage battery 6 to the drive motor 3. By doing so, the inverter 4 controls the rotation of the drive motor 3.

That is, the inverter 4 is connected to the high voltage battery 6 via a pair of main cables 12, 12, as shown in FIG. The inverter 4 is also connected to the drive motor 3 via three output cables 13, 13, 13.

Inside the inverter 4, an inverter circuit 4a including a plurality of switching elements such as IGBTs and a capacitor is provided. The inverter 4 generates controlled three-phase alternating current using the direct current voltage supplied from the high voltage battery 6 by controlling these switching elements on and off. By outputting the alternating current to the drive motor 3 through the output cable 13, the drive motor 3 rotates with the required output.

The converter 5 is a known device (so-called DC/DC converter) that converts DC power into DC power of a different voltage. Converter 5 is also arranged in motor room 1b together with drive motor 3. As shown in FIG. 2, converter 5 is connected to high voltage battery 6 via a pair of relay cables 14, 14 and a pair of main cables 12, 12. The converter 5 is also connected to a low voltage power supply system 15 .

Inside the converter 5, a step-down circuit 5a including a plurality of switching elements such as IGBTs, capacitors, and coils is provided. Converter 5 steps down the high voltage power of high voltage battery 6 and outputs it to low voltage power supply system 15 by controlling these switching elements on and off.

A low voltage battery 7 is connected to the constant voltage power supply system 15 . The low voltage battery 7 is a secondary battery with a rated voltage of 12V (24V in some cases). That is, the low voltage power supply system 15 is configured to be able to supply 12V DC power. Many electrical devices mounted on the automobile 1 are connected to a low-voltage power supply system 15.

As a result, electrical devices such as the inverter 4, converter 5, control device 10, and electric pump 41 (described later), including general electrical components such as headlights and audio equipment, are supplied with power from the low-voltage power supply system 15. It is operated by. Converter 5 therefore uses power from high voltage battery 6 to charge low voltage battery 7 or to directly power these electrical devices.

(Charging route for high voltage battery 6)
In order to charge the high voltage battery 6, the automobile 1 is provided with a charging plug 9, a charger 8, etc. As shown in FIG. 1, charging plug 9 is located at the rear of automobile 1. The charger 8 is arranged at the rear of the automobile 1, specifically below the trunk room 1c, so as to be located near the charging plug 9.

As shown in FIG. 2, this automobile 1 is provided with two charging paths (normal charging path 20 and quick charging path 30). Charging using the quick charging path 30 (quick charging) can charge the battery in a shorter time than charging using the normal charging path 20 (normal charging). The charging plug 9 is provided with plugs (high voltage plug 9a and low voltage plug 9b) corresponding to each of the normal charging path 20 and the quick charging path 30.

The normal charging path 20 is a path for indirectly charging the high-voltage battery 6 using a low-voltage alternating current supplied from an external power source with a voltage lower than that of the high-voltage battery 6, that is, a normal commercial power source such as 100V or 200V. The normal charging path 20 includes a low voltage plug 9b, a pair of upstream low voltage cables 21, 21, a charger 8, a pair of downstream low voltage cables 22, 22, and the like.

The quick charging path 30 is a path for directly charging the high voltage battery 6 using high voltage direct current supplied from an external power source with a voltage equal to or higher than that of the high voltage battery 6, that is, a specific power source such as a charging station. . The quick charging path 30 includes a high voltage plug 9a, a pair of high voltage cables 31, 31, and the like.

The high voltage plug 9a is connected to the high voltage battery 6 via a pair of high voltage cables 31, 31 and a pair of main cables 12, 12. The low voltage plug 9b connects to the high voltage battery via a pair of upstream low voltage cables 21, 21, a charger 8, a pair of downstream low voltage cables 22, 22, and a pair of main cables 12, 12. 6 is connected.

When a connector of a specific power source is connected to the high voltage plug 9a, the high voltage battery 6 can be directly charged. On the other hand, when a connector of a commercial power source is connected to the low voltage plug 9b, in order to charge the battery, it is necessary to convert the alternating current of the commercial power source into direct current. Furthermore, since the voltage of the commercial power source is lower, it is necessary to boost the voltage.

The charger 8 has the function of converting alternating current into direct current and boosting the voltage. That is, inside the charger 8, a boosting/converting circuit 8a including a plurality of switching elements such as IGBTs, capacitors, and coils is provided. The charger 8 converts the alternating current input from the pair of upstream low voltage cables 21, 21 into direct current by controlling these switching elements on and off, and also boosts the voltage. , is output to a pair of downstream low voltage cables 22, 22.

(Electrical cooling system 40)
When the drive motor 3 is in operation, a current flows through a coil disposed inside the drive motor 3. At that time, electric resistance or the like generates heat, and the internal temperature of the drive motor 3 rises. If the internal temperature becomes too high, the motor performance will deteriorate and there is a risk that the drive motor 3 will be damaged. Therefore, the drive motor 3 needs to be cooled.

Furthermore, when the inverter 4, converter 5, or charger 8 is operated, so-called switching control is performed. At that time, these electrical circuits generate heat due to electrical resistance. If the temperature of the electrical circuit becomes too high, the electrical circuit may be damaged. Therefore, each of inverter 4, converter 5, and charger 8 requires cooling.

As shown in FIG. 3, this automobile 1 is equipped with a so-called water-cooled electrical system cooling system 40 (also simply referred to as cooling system 40) in order to cool each of these electrical devices that require cooling. There is. That is, this cooling system 40 cools the electrical devices that require cooling by circulating and supplying the coolant cooled by the radiator 2 to each of the electrical devices that require cooling.

The cooling system 40 includes an electric pump 41, a cooling circuit 42, a deaeration tank 43, and the like. The cooling circuit 42 consists of piping through which a cooling liquid flows. The cooling circuit 42 includes a plurality of heat exchange parts 42a configured to increase heat exchange efficiency by increasing the surface area. Each heat exchange section 42a is arranged at a heat generating location of each electrical device.

As mentioned above, the radiator 2 is placed on the front side of the automobile 1. On the other hand, the charger 8 is placed at the rear of the vehicle 1. In the case of this automobile 1, the drive motor 3 is arranged in a motor room 1b located on the front side of the automobile 1.

Furthermore, in the case of this automobile 1, the inverter 4, converter 5, electric pump 41, and deaeration tank 43 are also arranged in the motor room 1b. Specifically, as shown in FIG. 4, these electric devices are assembled to the drive motor 3 and arranged in a unitized state in the motor room 1b. Therefore, the cooling circuit 42 has a pair of extensions 42b, 42b that extend long in the front-rear direction along the lower side of the passenger compartment 1a of the automobile 1, and connects the charger 8 via these extensions 42b, 42b. configured to cool.

The coolant is a so-called antifreeze. The coolant contains water, ethylene glycol, etc., and does not freeze even at temperatures below freezing, such as -30°C. Coolant has a higher viscosity than water, and the lower the temperature, the higher its viscosity.

The electric pump 41 has an impeller 41a inside its casing, and sucks and discharges the coolant by rotating the impeller 41a (non-displacement pump). The electric pump 41 is connected to the upstream side of the radiator 2 in the cooling circuit 42 via piping. As the electric pump 41 operates, the coolant circulates through the cooling circuit 42 in the direction shown by arrow f in FIG.

The electric pump 41 operates under the control of the control device 10. In the control device 10, a reference output command value (for example, duty ratio) to the electric pump 41 is set in advance in accordance with the cooling system 40. When the cooling system 40 is used, the electric pump 41 is controlled to operate at a reference output (so-called on-off control). However, in this cooling system 40, the output of the electric pump 41 is not always constant. As will be described later, the output of the electric pump 41 is increased or decreased based on the detected value of the refrigerant temperature sensor 44.

The deaeration tank 43 is installed to remove air contained in the coolant. The deaeration tank 43 is connected to the downstream side of the radiator 2 in the cooling circuit 42 via piping. The degassing tank 43 is also arranged at the highest position of the cooling circuit 42, as shown in FIG.

Electric devices to be cooled (drive motor 3, inverter 4, converter 5, and charger 8, also simply referred to as electric devices) are arranged in series in the cooling circuit 42.

When these electrical devices are arranged in parallel in the cooling circuit 42, a branch portion is created in the cooling circuit 42. Since the branched portion impedes the smooth flow of the coolant, bubbles are likely to occur in the coolant. When air bubbles are generated in the coolant, air pockets are formed in the cooling circuit 42, particularly in the heat exchange portion 42a thereof, resulting in insufficient cooling locations (heat spots). By arranging the electrical device in series with the cooling circuit 42, the occurrence of such heat spots can be suppressed.

Further, in this cooling system 40, the converter 5, inverter 4, charger 8, and drive motor 3 are arranged downstream of the radiator 2 in this order.

The amount of heat generated by these electrical devices is the smallest in the converter 5, followed by the inverter 4, charger 8, and drive motor 3 in that order. By arranging electrical devices that generate less heat on the upstream side of the cooling circuit 42, each electrical device can be cooled more efficiently. For example, by cooling the drive motor 3 etc., the temperature of the coolant increases and it is possible to avoid a problem in which the converter 5 etc. located downstream thereof cannot be appropriately cooled.

A sensor (refrigerant temperature sensor 44) that detects the temperature of the coolant circulating in the cooling circuit 42 is arranged in the cooling circuit 42 on the downstream side of the heat exchange section 42a arranged in the drive motor 3. This position is where the temperature of the circulating coolant is highest.

If the cooling system 40 is controlled based on the detected value of the refrigerant temperature sensor 44 arranged in this manner, each electrical device arranged in the cooling circuit 42 can be maintained at an appropriate temperature with only one sensor. That is, if the detected value of the refrigerant temperature sensor 44 is equal to or less than a predetermined value, it can be estimated that the temperature of the coolant flowing through each electrical device is equal to or less than the predetermined value.

(Control device 10)
As shown in FIG. 1, a control device 10 is mounted on an automobile 1. The control device 10 includes hardware such as a CPU, RAM, and ROM, and software such as a control program implemented in the hardware. The control device 10 comprehensively controls the driving of the automobile 1.

As shown in FIG. 5, as a functional configuration, the control device 10 is provided with a pump control section 10a that controls the electric pump 41, and a motor control section 10b that controls the operation of the drive motor 3 by the inverter 4. ing. In addition to the refrigerant temperature sensor 44 described above, signals are also input to the control device 10 from various sensors such as a converter temperature sensor 45, an inverter temperature sensor 46, and a charger temperature sensor 47.

As shown in FIG. 3, converter temperature sensor 45 is installed in converter 5, detects the temperature of the heat generating part, and outputs the signal. The inverter temperature sensor 46 is installed in the inverter 4, detects the temperature of its heat generating part, and outputs a signal thereof. Charger temperature sensor 47 is installed in charger 8, detects the temperature of the heat generating part, and outputs the signal. Note that these temperature sensors may be ones that indirectly detect temperature from electric current or the like.

Control device 10 (motor control unit 10b) controls inverter 4 based on signals input from converter temperature sensor 45 and the like. For example, control device 10 determines whether there is a temperature abnormality in converter 5 or the like based on a signal input from converter temperature sensor 45 or the like. As a result, when the control device 10 determines that the temperature is abnormal, the motor control section 10b and the pump control section 10a cooperate, or the motor control section 10b alone performs control to limit the output of the drive motor 3. .

The control device 10 (pump control unit 10a) controls the electric pump 41 based on a signal input from the refrigerant temperature sensor 44. That is, the control device 10 causes the cooling system 40 to function appropriately so that the electric devices to be cooled, such as the drive motor 3 and the charger 8, do not become abnormal in temperature.

(Cooling by cooling system 40)
When the automobile 1 is driven, the drive motor 3 and the inverter 4 are operated. Converter 5 operates depending on the power state of low-voltage power supply system 15, such as when the capacity of low-voltage battery 7 decreases. On the other hand, charger 8 does not operate when vehicle 1 is driving.

When the automobile 1 is stopped, the drive motor 3 and the inverter 4 do not operate. Charging of the high voltage battery 6 is performed when the vehicle 1 is stopped. Charger 8 is activated at that time. Converter 5 operates according to the power state of low voltage power supply system 15.

That is, in this automobile 1, since the electric device operates both when the vehicle is in operation and when the vehicle is stopped, the cooling system 40 is also used accordingly. Specifically, when the automobile 1 is driven, the drive motor 3, inverter 4, and converter 5 operate and generate heat, so the electric pump 41 is operated to cool them. When the vehicle 1 is stopped, the charger 8 and converter 5 operate and generate heat, so the electric pump 41 is operated to cool them.

As described above, in normal cases, the electric pump 41 is controlled to operate at a predetermined standard output. When the temperature of the coolant increases and the detected value of the refrigerant temperature sensor 44 approaches the upper limit temperature of the electrical device (temperature upper limit value), the control device 10 reduces the output of the electric pump 41. increase. As a result, the flow rate of the coolant increases and heat exchange is promoted, so that it is possible to prevent the electric device from becoming abnormal in temperature.

On the other hand, when the temperature of the coolant decreases, the temperature of the electrical device is lower than the upper temperature limit, so high-level cooling is not required. Therefore, the electric pump 41 usually stops or its output is suppressed to the extent that its function is maintained.

However, the present inventors have discovered that even when the temperature of the coolant decreases, depending on the situation, the electrical device can become abnormal in temperature. That is, in the case of the automobile 1, it may be driven or charged at temperatures below freezing, such as -10° C., and antifreeze is used as the coolant. Therefore, the viscosity of the coolant is higher than that of water, and the lower the temperature, the higher the viscosity.

In the case of this automobile 1, the charger 8, which is one of the objects to be cooled, is arranged at the rear of the automobile 1, and the cooling circuit 42 is provided with an extension portion 42b extending from the front to the rear of the automobile 1. . Therefore, when the coolant is at a low temperature, a large flow resistance acts, making it difficult for the coolant to flow through the cooling circuit 42. Further, in the cooling circuit 42, a plurality of heat exchange parts 42a having a large flow resistance are arranged in series. Therefore, when the coolant is at a low temperature, it becomes even more difficult for the coolant to flow through the cooling circuit 42.

If the coolant becomes difficult to flow and does not circulate properly, the electrical equipment will not be able to exchange heat properly, even if the coolant temperature is low. As a result, a temperature abnormality (temperature abnormality at low temperature) may occur in the electrical device. In particular, since the cooling during charging is performed when the vehicle 1 is stopped, the total amount of heat generated is small, and only the converter 5 and the charger 8, which are disposed apart from each other, are operated. Therefore, the coolant tends to become low temperature, and temperature abnormalities tend to occur in these electrical devices.

Therefore, this cooling system 40 is configured to increase the output of the electric pump 41 even when the temperature of the cooling liquid is low. By increasing the output of the electric pump 41, the discharge pressure of the electric pump 41 increases. This promotes circulation of the coolant, thereby suppressing temperature abnormalities at low temperatures.

Next, such control of the electric pump 41 will be specifically explained, dividing it into cooling when the vehicle 1 is operating and cooling when the vehicle 1 is stopped.

(Cooling during operation of car 1)
FIG. 6 illustrates the contents of pump control information representing the output of the electric pump 41 with respect to the temperature of the coolant. Pump control information is stored in the control device 10. The control device 10 (pump control unit 10a) controls the electric pump 41 based on such pump control information. Note that the temperature of the coolant here corresponds to the temperature detected by the coolant temperature sensor 44. The output of the electric pump 41 corresponds to a command value (duty ratio: %) that the control device 10 instructs to the electric pump 41.

FIG. 7 shows an example of control of the electric pump 41 performed by the control device 10 when the automobile 1 is driven. When the key is pressed in and the driving of the automobile 1 is started, the control device 10 starts reading signals from various sensors such as the refrigerant temperature sensor 44 (step S1). Control device 10 also operates drive motor 3 and inverter 4, and operates converter 5 as necessary. At the same time, a command value is output so that the electric pump 41 operates (step S2).

This control example assumes that the temperature of the coolant at that time is tn, as shown in FIG. Therefore, the control device 10 operates the electric pump 41 so that the output of the electric pump 41 becomes D1. While the automobile 1 is in operation, the control device 10 controls whether the temperature of the coolant does not enter a region higher than a predetermined temperature (high temperature zone) or a region lower than a predetermined temperature (low temperature zone). The cooling system 40 is operated while the output of the electric pump 41 is maintained at D1.

When the amount of heat generated by the drive motor 3, inverter 4, etc. increases due to, for example, running uphill, the temperature of the coolant increases accordingly. This control example assumes that the temperature of the coolant has increased excessively. When the temperature of the coolant reaches a predetermined temperature t3 (for example, 60° C.) (Yes in step S3), the control device 10 outputs a command value to the electric pump 41 to increase the output (step S4). . Specifically, the output of the electric pump 41 is increased at a constant rate with respect to the amount of change in the temperature of the coolant.

Then, when the temperature of the coolant further increases and reaches a predetermined temperature t4 (for example, 70° C.) (Yes in step S5), the control device 10 changes the output of the electric pump 41 to that state (output D2 in FIG. 6). (step S6). Since the amount of circulating coolant increases and heat exchange is promoted, abnormal temperatures in the drive motor 3 and the like can be suppressed.

On the other hand, when the temperature of the coolant decreases due to a decrease in air temperature and reaches a predetermined temperature t2 (for example, 25° C.) (Yes in step S7), the control device 10 controls the electric pump 41 to increase the output. A command value is output to (step S8). Specifically, the output of the electric pump 41 is increased at a constant rate with respect to the amount of change in the temperature of the coolant.

This control example assumes that the temperature of the coolant has decreased excessively. When the temperature of the coolant further decreases and reaches a predetermined temperature t1 (for example, 7° C.) (Yes in step S9), the output of the electric pump 41 is maintained at that state (output D2 in FIG. 6) (step S10). .

In this way, in the cooling system 40 of the automobile 1, even when the temperature of the coolant enters a low temperature range below the predetermined temperature t2, which includes below 0° C., the circulation amount of the coolant is increased. This makes it possible to suppress a decrease in the flow rate of the coolant due to an increase in the viscosity of the coolant, thereby suppressing temperature abnormalities at low temperatures.

However, even if the output of the electric pump 41 is the same, the flow rate of the coolant at low temperatures is smaller than the flow rate of the coolant at high temperatures because of the high viscosity. However, since the temperature of the coolant itself is low, even a slight increase in flow rate can provide effective cooling.

Note that if the temperature of the coolant at the start of the control is not tn but below t2 or above t3, the control device 10 controls the electric pump 41 to operate with an output according to the temperature. . That is, the control device 10 controls the electric pump 41 to operate with an output according to the detected value of the refrigerant temperature sensor 44.

(Cooling when vehicle 1 is stopped)
FIG. 8 shows an example of control of the electric pump 41 performed by the control device 10 when the vehicle 1 is stopped. In FIG. 8, contents corresponding to FIGS. 6 and 7 are shown in a simplified manner.

When the vehicle 1 is stopped, power is not supplied to each electrical device mounted on the vehicle 1. When charging is started and a connector is connected to either the high voltage plug 9a or the low voltage plug 9b, power is supplied by the low voltage power supply system 15 in order to operate the control device 10 etc. Begins.

Control device 10 operates converter 5 in order to secure power for low-voltage power supply system 15 . The control device 10 also starts reading signals from various sensors such as the refrigerant temperature sensor 44 (step S21). The control device 10 further determines whether the charger 8 is operating, that is, whether the charging is normal charging or rapid charging (step S22).

When the vehicle 1 is stopped, the cooling system 40 is used when performing normal charging or rapid charging. During quick charging, charging is performed using the quick charging path 30. Therefore, during rapid charging, charger 8 does not operate, and only converter 5 operates (No in step S22). Cooling system 40 during rapid charging is used to cool converter 5.

During normal charging, since charging is performed using the normal charging path 20, not only the converter 5 but also the charger 8 are activated (Yes in step S22). Cooling system 40 during normal charging is used to cool converter 5 and charger 8. During normal charging, the charger 8 is normally operated at full capacity continuously, so the charger 8 is likely to become abnormal in temperature.

Further, the circulation of the coolant to the charger 8 is performed via the long extension 42b. Therefore, the charger 8 is susceptible to a decrease in the flow rate of the coolant due to an increase in the viscosity of the coolant, and is prone to temperature abnormalities at low temperatures.

Therefore, higher cooling performance is required during normal charging than during quick charging. Therefore, in this cooling system 40, the output of the electric pump 41 is set to be larger during normal charging than during quick charging.

Step S23 shows pump control information (normal charging information) representing the output of the electric pump 41 with respect to the coolant temperature during normal charging. Step S24 shows pump control information (quick charging information) representing the output of the electric pump 41 with respect to the temperature of the coolant during quick charging.

Each of the normal charging information and the rapid charging information is stored in the control device 10 in the same way as the pump control information shown in FIG. Similarly to the pump control information shown in FIG. 6, each of the normal charging information and the quick charging information is provided on both sides of a predetermined temperature range (medium temperature range) in which the electric pump 41 operates with a constant output. has a temperature range in which the output of the electric pump 41 is increased, that is, a predetermined low temperature range and a predetermined high temperature range.

D1(N) of the normal charging information and D1(H) of the quick charging information correspond to D1 of the pump control information shown in FIG. 6, and D2(N) of the normal charging information and D1(H) of the quick charging information Each of the information D2(H) corresponds to the pump control information D2 shown in FIG. D1 (N) of the normal charging information has a higher output than D1 (H) of the quick charging information. D2 (N) of the normal charging information has a higher output than D2 (H) of the quick charging information.

Therefore, during normal charging when the charger 8 is operated, the flow of the coolant is further increased, so that the charger 8 and the converter 5 can be stably protected from temperature abnormalities. During rapid charging when the charger 8 is not operated, the output of the electric pump 41 is suppressed, so power consumption can be reduced.

Further, in the normal charging information, the lower limit temperature of the high temperature range, that is, the temperature at which the electric pump 41 starts increasing, is set to a lower temperature than in the quick charging information (t3'<t3). As a result, the cooling performance is further improved at an earlier stage when the temperature is high, so that charger 8 and converter 5 can be more stably protected from temperature abnormalities.

The control device 10 refers to the input detected value of the refrigerant temperature sensor 44 in the normal charging information or the rapid charging information, and operates the electric pump 41 with an output corresponding to the detected value (step S25). .

<Modified example>
FIG. 9 shows a modification of the control of the electric pump 41 performed by the control device 10 when the vehicle 1 is stopped.

The basic contents are the same as the control shown in FIG. In this modification, the content of the information during quick charging is different from the control described above. The same reference numerals are used for the same contents as the control described above, and the explanation thereof will be omitted.

The quick charging information of this modification is different from the control described above, and is set so as not to increase the output of the electric pump 41 in a low temperature range. That is, as shown in step S24' in FIG. 9, the output of the electric pump 41 is maintained at a constant reference value D1 (H) in a temperature range other than a predetermined high temperature range.

During rapid charging, the converter 5 that retains the power of the low-voltage power supply system 15 is to be cooled. Compared to the charger 8, which is operated at full capacity during charging, the converter 5 generates less heat and is less prone to temperature abnormalities. If the temperature is low, a cooling effect can also be obtained through heat radiation. Therefore, in this modification, the output of the electric pump 41 is set not to be increased in a low temperature range. Thereby, the output of the electric pump 41 is suppressed, so power consumption can be further reduced.

Note that the electrical cooling system according to the disclosed technology is not limited to the embodiments described above, and includes various other configurations.

For example, in the above-described embodiment, an electric vehicle is used as an example of the vehicle, but the present invention can also be applied to a vehicle that can run using a drive other than electric power. That is, the disclosed technology can also be applied to hybrid vehicles, plug-in hybrid vehicles, range extenders (REX), and the like.

The configuration of the control device is also an example. For example, the pump control unit 10a may be configured as an independent control device. The type, number, arrangement, etc. of electrical devices to be cooled can be changed according to specifications.

1 Automobile (vehicle)
2 Radiator (heat exchanger)
3 Drive motor (electrical device)
4 Inverter (electrical device)
5 Converter (electrical device)
6 High voltage battery 7 Low voltage battery 8 Charger (electrical device)
9 Charging plug 10 Control device (pump control device)
20 Normal charging path 30 Quick charging path 40 Electrical cooling system 41 Electric pump 42 Cooling circuit 43 Deaeration tank 44 Refrigerant temperature sensor

Claims (6)

An electrical cooling system installed in a vehicle capable of driving using electric power,
a charger located on the rear side of the vehicle;
The charger includes an electric pump that circulates the coolant and a heat exchanger that is disposed on the front side of the vehicle and cools the coolant by exchanging heat with outside air, and the charger is disposed so as to be able to exchange heat with the coolant. cooling circuit,
a refrigerant temperature sensor that detects the temperature of the coolant circulating in the cooling circuit;
a pump control device that controls the electric pump based on a detected value of the refrigerant temperature sensor;
Equipped with
The vehicle is
A high-voltage battery that stores power for driving,
a normal charging path for charging the high voltage battery by boosting a low voltage supplied from an external power source with the charger;
a drive motor that uses electric power from the high-voltage battery to generate driving force for driving the vehicle;
an inverter interposed between the drive motor and the high voltage battery to control rotation of the drive motor;
a converter that steps down the voltage of the high voltage battery to a predetermined low voltage that is supplied to each of the charger and the inverter to enable its operation;
has
Together with the charger, each of the drive motor, the inverter, and the converter is to be cooled by the cooling circuit, and the drive motor, the inverter, the converter, and the charger are connected in series with the cooling circuit. placed,
The refrigerant temperature sensor is disposed in the cooling circuit downstream of any of the parts that exchange heat with the drive motor, the inverter, the converter, and the charger,
When the refrigerant temperature sensor detects a temperature in a low temperature range including at least a sub-zero region of 0° C. or less, the pump control device is configured to increase the output of the electric pump in accordance with a decrease in temperature. and an electric cooling system in which the output of the electric pump is maintained constant even before reaching the sub-zero temperature range. An electrical cooling system installed in a vehicle capable of driving using electric power,
a charger located on the rear side of the vehicle;
The charger includes an electric pump that circulates the coolant and a heat exchanger that is disposed on the front side of the vehicle and cools the coolant by exchanging heat with outside air, and the charger is disposed so as to be able to exchange heat with the coolant. cooling circuit,
a refrigerant temperature sensor that detects the temperature of the coolant circulating in the cooling circuit;
a pump control device that controls the electric pump based on a detected value of the refrigerant temperature sensor;
Equipped with
The pump control device is configured to increase the output of the electric pump when the refrigerant temperature sensor is detecting a temperature in a low temperature range including at least a sub-zero region of 0° C. or less,
The vehicle is
A high-voltage battery that stores power for driving,
a normal charging path for charging the high voltage battery by boosting a low voltage supplied from an external power source with the charger;
a quick charging path for charging the high voltage battery without using the charger using a high voltage supplied from an external power source;
has
The pump control device increases the output of the electric pump in the low temperature range so that the output of the electric pump is higher when charging through the normal charging path than when charging through the quick charging path. Electrical cooling system. An electrical cooling system installed in a vehicle capable of driving using electric power,
a charger located on the rear side of the vehicle;
The charger includes an electric pump that circulates the coolant and a heat exchanger that is disposed on the front side of the vehicle and cools the coolant by exchanging heat with outside air, and the charger is disposed so as to be able to exchange heat with the coolant. cooling circuit,
a refrigerant temperature sensor that detects the temperature of the coolant circulating in the cooling circuit;
a pump control device that controls the electric pump based on a detected value of the refrigerant temperature sensor;
Equipped with
The pump control device is configured to increase the output of the electric pump when the refrigerant temperature sensor is detecting a temperature in a low temperature range including at least a sub-zero region of 0° C. or less,
The vehicle is
A high-voltage battery that stores power for driving,
a normal charging path for charging the high voltage battery by boosting a low voltage supplied from an external power source with the charger;
a quick charging path for charging the high voltage battery without using the charger using a high voltage supplied from an external power source;
has
When charging through the normal charging path, the pump control device increases the output of the electric pump in the low temperature range, and when charging through the quick charging path, the pump control device increases the output of the electric pump in the low temperature zone. Electrical cooling system that does not increase the output of the The electrical cooling system according to claim 2 or 3,
The vehicle further includes:
a drive motor that uses electric power from the high-voltage battery to generate driving force for driving the vehicle;
an inverter interposed between the drive motor and the high voltage battery to control rotation of the drive motor;
a converter that steps down the voltage of the high voltage battery to a predetermined low voltage that is supplied to each of the charger and the inverter to enable its operation;
has
Together with the charger, each of the drive motor, the inverter, and the converter is to be cooled by the cooling circuit,
An electrical cooling system, wherein the drive motor, the inverter, the converter, and the charger are arranged in series in the cooling circuit. The electrical cooling system according to claim 1 or 4,
An electrical cooling system in which the converter, the inverter, the charger, and the drive motor are arranged in this order downstream of the heat exchanger. The electrical cooling system according to claim 4 or 5,
An electrical cooling system in which the refrigerant temperature sensor is disposed downstream of a portion of the cooling circuit that exchanges heat with the drive motor.

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