JPH06293210A - Electric vehicle - Google Patents

Abstract

PURPOSE:To enhance the efficiency of a refrigerating cycle by using the remaining heat of a battery set inside the refrigerating cycle as a refrigerant evaporation means in heating operation to prevent the lowering of heat exchanging capacity due to frosting, etc. CONSTITUTION:A steam refrigerant heated and pressurized in a compressor 1 heats a cabin through a heat exchanger 5 in the cabin, and then a specified amount of liquid refrigerant produced is reduced in pressure at an expansion valve 7b and returned back to the compressor 1 after cooling a driving motor 6. When the cooling load of the driving motor 6 is small, extra refrigerant is flown into battery 12. The battery 12 is controlled by a control circuit 14 using a signal from a temperature sensor 13 and, when the battery 12 is heated to a specified working temperature, a solenoid valve 10b is opened to cool it and to evaporate gas-liquid refrigerant by remaining heat. When the temperature of the battery 12 is lowered, the solenoid valve 10b is closed, and the refrigerant is evaporated by the heat exchanger 4 outside the cabin. Thus the steam load of the heat exchanger 4 outside the cabin can be reduced to prevent evaporation and lowering of heating capacity due to frosting, refrigerant accumulation, etc., for improvement of the efficiency and reliability of a refrigerating cycle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle equipped with an air conditioning system.

[0002]

2. Description of the Related Art Electric vehicles have been attracting attention as a solution to the problems of greenhouse effect and air pollution caused by the concentration of carbon dioxide in the atmosphere by the exhaust gas from current internal combustion engines. However, the traveling distance per charge of an electric vehicle cannot be said to be sufficient due to the problem of the electric capacity of the storage battery. Further, heat generation of the drive motor increases with the amount of current flowing through the drive motor, and the temperature rises. When the temperature rises abnormally, the drive motor may be damaged. Further, the heat generation of the driving motor causes demagnetization of the magnet, which lowers the efficiency of the driving motor, so that cooling of the driving motor becomes a particularly important issue.

To address the above problems, a drive motor is installed in the refrigeration cycle of an air conditioner for automobiles, and during the summer cooling operation, the refrigerant circuit is switched according to the amount of heat generated by the drive motor to serve as a cooling load. At the same time, an efficient cooling system has been proposed in which the state of the refrigerant flowing to the drive motor is changed to prevent overcooling. In this system, the amount of heat generated by the drive motor in winter is almost unchanged from that in summer, but the outside air temperature is low, so the load of forced cooling due to the effect of natural cooling is considerably reduced.
On the contrary, the heating load in the passenger compartment is larger than the cooling load in the normal summer, and the heating efficiency of the heat pump type heating cycle composed of only compressed refrigerant is inferior to the cooling efficiency. The machine is rotated at a higher speed to circulate more refrigerant. Therefore, the difference between the amount of liquid refrigerant generated by cooling by indoor heating and the amount of refrigerant required for cooling the drive motor must be evaporated by heat exchange with the outside air in the vehicle exterior heat exchanger.

[0004]

However, when the outside air temperature becomes extremely low (for example, 0 ° C. or lower), the evaporation temperature of the refrigerant must be set lower than that, and further, the difference between the two temperatures becomes small. If it is small, the heat exchange capacity cannot be sufficiently obtained, so it is necessary to lower the evaporation pressure to about 0.15 MPa with R-134a, and there is a risk that the suction pressure of the compressor becomes a negative pressure. Further, in order to improve the heat exchange capacity, it is necessary to increase the rotation speed of the blower of the heat exchanger to increase the amount of blown air. As a result, the power consumption by the operation of the blower increases and the life of the storage battery decreases. Also, the evaporation temperature is -10 ℃
When the temperature becomes below, frost is formed on the heat exchanger, which further reduces the heat exchange capacity. Therefore, in such a state, the gas-liquid refrigerant does not completely evaporate and accumulates in the pipes in front of the heat exchanger, resulting in a decrease in the amount of refrigerant returning to the compressor, which reduces the indoor heating capacity and further prevents vaporization. As the refrigerant increases,
The refrigeration cycle falls into an inoperable state.

[0005]

SUMMARY OF THE INVENTION The present invention solves this drawback, and in an electric vehicle in which an electric motor is used as a drive source and the electric motor and a storage battery are installed in a refrigeration cycle of an automobile air conditioner, This is achieved by using the residual heat as a refrigerant evaporation means during heating operation.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a refrigeration cycle during heating operation of an electric vehicle of the present invention. Compressed by compressor 1,
The high-temperature, high-pressure vapor refrigerant that has been oil-separated by the oil separator 2 is sent to the vehicle interior heat exchanger 5 by the four-way valve 3. Here, heat is exchanged with the air in the room to heat the room, and as a result, the refrigerant is cooled to become a liquid refrigerant. Here, the three-way valve 9a is closed with respect to the direction of the three-way valve 9b, and the liquid refrigerant is sent to the drive electric motor 6 by bypassing the expansion valve 7a by the check valve 8b. The liquid refrigerant is appropriately decompressed when flowing through the expansion valve 7b by the check valve 8a, flows through the electromagnetic valve 10a in the open state to the driving electric motor 6, cools the driving electric motor 6, and then, in the direction of the three-way valve 9a. And is returned to the compressor 1 through the closed three-way valve 9b and the accumulator 11. Here, since the cooling load of the drive motor 6 in winter is small, the liquid refrigerant that cannot be evaporated by the drive motor 6 among the refrigerants required for heating the vehicle interior is evaporated as follows. The storage battery 12 is equipped with a temperature sensor 13, whose signal is processed by the control circuit 14,
Manages the temperature of. When the storage battery 12 reaches the standard operating temperature, the solenoid valve 10b is opened, and when the operating temperature is lower than the operating temperature or once the operating temperature is reached, the solenoid valve 10b is closed. . The control circuit 14 has an appropriate hysteresis to prevent the solenoid valve 10b from frequently operating. Due to this control, the storage battery 12 does not reach the operating temperature sufficiently at the time of starting the electric vehicle.
With b kept closed, no refrigerant flows into the storage battery 12,
The remaining refrigerant evaporation is performed only in the vehicle exterior heat exchanger 4. The cryogenic gas-liquid refrigerant decompressed by the expansion valve 7c in the vehicle exterior heat exchanger 4 evaporates by heat exchange with the outside air and returns to the compressor 1 through the four-way valve 3 and the accumulator 11. On the other hand, when the storage battery 12 reaches the operating temperature, open the solenoid valve 10b,
The gas-liquid refrigerant decompressed by the expansion valve 7b is also sent to the storage battery 12, and the residual heat of the storage battery 12 completely evaporates the gas-liquid refrigerant and returns it to the compressor 1 through the accumulator 11. Here, when the temperature of the storage battery 12 falls below the operating temperature due to excessive refrigerant evaporation in the storage battery 12, the electromagnetic valve 10b is closed, and the refrigerant is evaporated only by the exterior heat exchanger 4 until the operating temperature is reached again. I will. The distribution of the refrigerant to the storage battery 12 and the exterior heat exchanger 4 is such that the evaporation pressure on the storage battery 12 side is high and the heating degree is low, while the exterior heat exchanger 4
By lowering the evaporation pressure and increasing the degree of heating, the amount of refrigerant sent to the storage battery 12 is increased, and the amount of heat exchange in the vehicle exterior heat exchanger 4 can be reduced. Further, when a sufficient margin is generated in the residual heat of the storage battery 12, the exterior heat exchanger 4 may not be used for the evaporation of the refrigerant at all, and may be evaporated only by the storage battery 12. Due to the above action, the evaporation load of the refrigerant in the vehicle exterior heat exchanger 4 is reduced, problems such as frost formation and refrigerant accumulation are solved, and the amount of air blown by the blower can be significantly reduced, which is safe and reliable. A refrigeration cycle with high properties can be configured.

FIG. 2 is an explanatory view of the refrigeration cycle during the cooling operation of the electric vehicle of the present invention. The high-temperature high-pressure vapor refrigerant that has been compressed by the compressor 1 and separated by the oil separator 2 is sent to the exterior heat exchanger 4 via the four-way valve 3 whose flow path is switched to be cooled. The low-temperature high-pressure liquid refrigerant after cooling passes through the check valve 8a and the driving electric motor 6
And is sent to both directions of the vehicle interior heat exchanger 5. The refrigerant sent in the direction of the driving electric motor 6 is decompressed by the expansion valve 7b to become a low temperature gas-liquid refrigerant, flows to the driving electric motor 6 through the electromagnetic valve 10a and the three-way valve 9b, and sufficiently cools the driving electric motor 6. The refrigerant that has cooled and increased in temperature is accumulator 11
Return to the compressor via. Here, during the cooling operation, the storage battery 12
Regardless of the temperature, the solenoid valve 10b is closed and no refrigerant flows to the storage battery 12.

As described above, in an electric vehicle in which the electric motor is used as a drive source and the electric motor and the storage battery are installed in the refrigerating cycle of the automobile air conditioner, the residual heat of the storage battery is used as the refrigerant vaporizing means during the heating operation, so that the storage battery Since it is possible to evaporate the gas-liquid refrigerant that cannot be evaporated by the electric motor on the side, the evaporation load is reduced due to the decrease in the refrigerant evaporation amount in the vehicle exterior heat exchanger, and problems such as frost formation and refrigerant accumulation are solved. Moreover, the amount of air blown by the blower can be significantly reduced, and the efficiency and reliability of the refrigeration cycle are improved. Therefore, it is possible to avoid wasteful consumption of the storage battery, and thus it is possible to configure an electric vehicle with improved traveling distance per charge and overall high energy efficiency. When the temperature of the storage battery has not reached the operating temperature immediately after starting the electric vehicle, it is not used for refrigerant evaporation, and therefore the performance of the storage battery is hardly adversely affected. Further, since the storage battery can be easily separated from the refrigeration cycle during the cooling operation, the refrigerant flow, the cooling effect of the vehicle interior and the drive motor, and the overall energy efficiency can be operated without any change.

[0009]

INDUSTRIAL APPLICABILITY As described above, the present invention uses an electric motor as a drive source and installs the electric motor and a storage battery in the refrigeration cycle of an air conditioner for a vehicle in which the residual heat of the storage battery is used as a refrigerant evaporation means during heating operation. By
Since it is possible to evaporate the gas-liquid refrigerant only with the storage battery and the heat exchanger outside the vehicle compartment, or with the storage battery, the evaporation amount of the refrigerant in the heat exchanger outside the vehicle compartment is reduced and the evaporation load in the heat exchanger outside the vehicle compartment is reduced. It is possible to prevent the evaporation capacity and heating capacity from decreasing due to frost and refrigerant accumulation, etc., and to significantly reduce the amount of air blown by the blower, improve the efficiency and reliability of the refrigeration cycle, and avoid wasteful consumption of the storage battery. An electric vehicle with improved mileage per charge and overall high energy efficiency can be provided.

[Brief description of drawings]

FIG. 1 is an explanatory view of a refrigeration cycle during heating operation of an electric vehicle of the present invention.

FIG. 2 is an explanatory diagram of a refrigeration cycle during cooling operation of the electric vehicle of the present invention.

[Explanation of symbols]

 1 compressor 2 oil separator 3 four-way valve 4 vehicle exterior heat exchanger 5 vehicle interior heat exchanger 6 driving motor 7a expansion valve 7b expansion valve 7c expansion valve 8a check valve 8b check valve 9a three-way valve 9b three-way valve 10a electromagnetic Valve 10b Solenoid valve 11 Accumulator 12 Storage battery 13 Temperature sensor 14 Control circuit

Claims (1)

[Claims] 1. In an electric vehicle having an electric motor as a drive source and the electric motor and a storage battery installed in a refrigeration cycle of an automobile air conditioner, the residual heat of the storage battery is used as a refrigerant evaporation means during heating operation. Electric car to do.