JPH07101227A - Vehicle heat pump air conditioner - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a heat pump type air conditioner for a vehicle, which can improve the heating capacity by effectively utilizing the waste heat of the cooling water of the drive system even in the vehicle using an electric motor as a drive source. A heat dissipation vehicle interior heat exchanger 7 to which the refrigerant compressed by the compressor 1 is introduced, a pressure reducer 9 for expanding and decompressing the refrigerant passing through the heat dissipation vehicle interior heat exchanger 7, and the pressure reducer. In a heat pump type air conditioner for a vehicle equipped with a heat absorption vehicle interior heat exchanger 10 through which a refrigerant passing through 9 is guided, waste heat of cooling water of a drive system including a vehicle drive electric motor 20 is recovered during heating operation, A heater 30 is provided which raises the temperature of the refrigerant passing through the heat-absorbing passenger compartment heat exchanger 10 toward the suction side of the compressor 1 by this heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner for guiding a refrigerant compressed by a compressor to a heat exchanger for heat generation in a vehicle compartment and exchanging heat with air sent into the vehicle compartment for heating.

[0002]

2. Description of the Related Art As an apparatus of this kind, Japanese Patent Laid-Open No. 2-290 is known.
As disclosed in Japanese Patent No. 475, the heat-generating vehicle interior heat exchanger to which the refrigerant compressed by the compressor is introduced is divided into two, and waste heat of the engine cooling water is divided between the divided heat exchangers. In some cases, a heating device for recovering heat is installed, and the refrigerant discharged from the heat-generating vehicle interior heat exchanger on the upstream side during heating operation is guided to the heating device to be heated to improve the heating capacity.

[0003]

In the apparatus described in the above publication, the temperature of the refrigerant flowing into the heater is about 60 ° C. On the other hand, in a vehicle equipped with a gasoline engine (hereinafter referred to as a gasoline vehicle), the temperature of the engine cooling water is maintained at a minimum of about 80 ° C by a thermostat provided in the cooling water circulation system. Therefore, as long as it is applied to a gasoline vehicle, the heat exchange by the heater can be performed without any problem. However, in an electric vehicle that uses an electric motor as a drive source for the vehicle, the temperature of the cooling water for the electric motor and its controller rises only up to about 20 to 30 ° C. For this reason, if the above-mentioned device is used, the refrigerant is cooled by the heater, and the heating capacity cannot be improved by utilizing the waste heat of the cooling water. However, in an electric vehicle, the power consumption of the compressor is suppressed because the cruising range of the vehicle is prioritized, so it is necessary to realize a high cooling and heating capacity with as little power as possible, and even if the cooling water is cold, the waste heat It is desirable to reduce the load on the compressor by using the.

An object of the present invention is to provide a heat pump type air conditioner for a vehicle, which can improve the heating capacity by effectively utilizing the waste heat of the cooling water of the drive system even in a vehicle using an electric motor as a drive source. is there.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 showing an embodiment, the present invention relates to a heat radiating vehicle interior heat exchanger 7 to which a refrigerant compressed by a compressor 1 is introduced, and a heat radiating vehicle. A heat pump type air conditioner for a vehicle, comprising a pressure reducer 9 for expanding and decompressing a refrigerant having passed through an indoor heat exchanger 7, and a heat absorbing vehicle interior heat exchanger 10 to which the refrigerant having passed through the pressure reducer 9 is guided. Applied. Then, during heating operation, the waste heat of the cooling water of the drive system including the vehicle driving electric motor 20 is recovered, and the temperature of the refrigerant that passes through the heat absorption vehicle interior heat exchanger 10 toward the suction side of the compressor 1 is recovered by this heat. By providing the heating means 30 for raising, the above-mentioned object is achieved.

[0006]

In the heating operation of the vehicle heat pump type air conditioner, when the refrigerant after being decompressed by the decompressor 9 is guided to the heat-absorbing passenger compartment heat exchanger 10 and exchanges heat with the air sent to the passenger compartment, the heat is absorbed. The temperature of the refrigerant flowing out from the vehicle interior heat exchanger 10 is much lower than the temperature of the refrigerant before flowing into the decompressor 9, and usually falls to about 0 to 5 ° C. Therefore, even if the temperature of the cooling water guided to the heating means 30 is low (20 to 30 ° C. in a general electric vehicle), the heat of the heating means 30
The refrigerant can be recovered and heated.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a refrigerant circuit of a heat pump type air conditioner according to the present embodiment and a circulation circuit of a cooling water of a vehicle drive system. The upper side and the lower side of the line L-L in the drawing are the outside of the vehicle compartment and the lower side thereof are the vehicle interior. . Like the well-known heat pump type air conditioner, the device of this embodiment also switches the compressor 1 for compressing the refrigerant, the oil separator 2 connected to the discharge side of the compressor 1 for separating the oil in the refrigerant, and the refrigerant flow path during cooling and heating. Solenoid valves 3, 4, a condenser 5 for exchanging heat between the refrigerant and the outside air, a check valve 6 for preventing backflow of the refrigerant from the solenoid valve 4 to the outflow side of the condenser 5, air and refrigerant sent to the vehicle interior A sub-condenser 7 for exchanging heat between the sub-condenser, a liquid tank 8 for gas-liquid separation of the refrigerant flowing out from the sub-condenser 7, an expansion valve 9 for expanding and decompressing the refrigerant, a refrigerant after decompression and air sent to the vehicle interior. An evaporator 10 for exchanging heat with and an accumulator 11 for keeping the suction pressure of the compressor 1 constant.

The sub-condenser 7, the expansion valve 9 and the evaporator 10 are mounted inside the air conditioning duct 12.
An air inlet (not shown) and a blower fan unit 13 that blows air are provided upstream (to the left in the drawing) of the evaporator 10 in the air conditioning duct 12. Immediately before the sub-capacitor 7, an air mix door 14 that can be rotated by an actuator (not shown) is provided. Air mix door 14
The flow rate of the air passing through the sub-condenser 7 changes according to the rotational position of the air conditioner, and the temperature of the air flowing out from the air conditioning duct 12 changes. Downstream of the air conditioning duct 12, a distributor (not shown) that distributes air to the air outlets provided at various places in the vehicle compartment is connected.

Reference numeral 20 is an electric motor for driving the vehicle, 21 is a controller for controlling the operation of the electric motor 20, and these are cooled by cooling water pumped by a water pump 22. When the temperature of the cooling water is equal to or higher than the predetermined temperature, the thermostat 23 opens and the cooling water is cooled by the radiator 24.
When the temperature is lower than the predetermined temperature, the thermostat 23 is closed and the cooling water from the water pump 22 bypasses the radiator 24 and is guided to the electric motor 20 side. In addition, 25 is an electric fan. The compressor 1 is driven by an electric motor 20.

A part of the cooling water guided to the electric motor 20 is guided to the heater 30 according to the opening operation of the water valve 26. The water valve 26 is opened by the control device (not shown) when the air conditioner is in the heating operation, and is closed during the cooling operation. Inside the heater 30, a pipeline of the refrigerant that flows out from the evaporator 10 and goes to the suction side of the compressor 1 is laid out, and heat exchange between the refrigerant and the cooling water is possible. The cooling water flowing out of the heater 30 is used as a check valve 2
It is returned to the discharge side of the water pump 22 via 7.

In the apparatus having the above structure, the solenoid valve 3 is switched to the closed position and the solenoid valve 4 is switched to the open position during the heating operation, and the high-temperature and high-pressure refrigerant discharged from the compressor 1 is directly guided to the sub-condenser 7. The heat of the refrigerant flowing into the sub-condenser 7 is radiated to the air passing through the sub-condenser 7, whereby the air taken into the air conditioning duct 12 is sufficiently heated and sent out to the passenger compartment. The refrigerant flowing out from the sub-condenser 7 is guided to the heater 30 via the liquid tank 8, the expansion valve 9 and the evaporator 10. During the heating operation, the water valve 26 is opened and the cooling water of the electric motor 20 is guided to the heater 30. Since the temperature of the refrigerant flowing out of the evaporator 8 becomes sufficiently low due to the pressure reduction in the expansion valve 9, even if the temperature of the cooling water of the electric motor 20 is lower than that of the conventional gasoline vehicle, the heat of the cooling water by the heater 30 is reduced. Can be recovered to heat the refrigerant. Generally, evaporator 1
The temperature of the refrigerant flowing from 0 is 0 to 5 ° C, and the electric motor 20
The temperature of the cooling water is 20 to 30 ° C, and if the temperature difference is within this range, the heat of the cooling water can be sufficiently recovered by the heater 30 to heat the refrigerant.

During the cooling operation, the solenoid valve 3 is switched to the open position and the solenoid valve 4 is switched to the closed position, and the high temperature and high pressure refrigerant discharged from the compressor 1 is cooled by the condenser 5, and then the sub condenser 7 and the liquid tank 8 are connected. Through expansion valve 9
Be led to. The temperature of the refrigerant flowing into the evaporator 10 decreases due to the pressure reduction when passing through the expansion valve 9, and the heat of the air taken into the air conditioning duct 12 is taken away when passing through the evaporator 10 and sent to the vehicle interior. Is cooled. Since the water valve 26 is closed and the cooling water is not guided to the heater 30 during the cooling operation, the refrigerant flowing out from the evaporator 10 flows into the accumulator 11 without being heated by the heater 30. Therefore, an increase in heat load during cooling can be prevented.

Since the engine cooling water of a gasoline-powered vehicle is at least 80 ° C. or higher, if it is introduced into the heater 30, the refrigerant temperature will rise too high and the compressor 1 may burn. That is, in order to utilize the heat of the engine cooling water in a gasoline vehicle, it is necessary to install a heater on the high pressure side upstream of the expansion valve 9 inevitably, and the heater on the low pressure side as in this embodiment. It was traditionally considered impossible to install.

FIG. 2 is a schematic explanatory view showing changes in refrigerant pressure and enthalpy during heating operation of the heat pump type air conditioner. Assuming that the heater 30 is not provided, the refrigerant at the A ₀ point compressed by the compressor 1 moves to the B ₀ point due to heat dissipation when passing through the sub-condenser 7, and is expanded to the C ₀ point by the expansion of the expansion valve 9. It is assumed that it moves to the point D ₀ due to heat absorption when passing through the evaporator 10, and returns to the point A ₀ due to compression by the compressor 1. At this time, the work of the compressor 1 is equal to the amount of increase in enthalpy from the D ₀ point to the A ₀ point. A heater 3 is used in an air conditioner having such a cycle.
When 0 is added, the pressure P _L0 on the low pressure side increases to P _L1 due to the heating of the refrigerant by the heater 30, and the C ₀ point and the D ₀ point move to the C ₁ point and the D ₁ point, respectively. At this time, the pressure P _H0 on the high pressure side
Is maintained as usual, the work of the compressor 1 is D ₀
The power consumption of the compressor 1 is reduced by an amount corresponding to the difference in enthalpy between the point and the point D ₁ . The heating capacity does not change because the pressure P _H0 on the high pressure side is maintained.
When maintaining the work of the compressor 1 as usual,
_{The 0} point moves by an amount corresponding to the difference in enthalpy between the D ₀ point and the D ₁ point and moves to the A ₂ point, and the high-pressure side pressure P _H0 becomes P _H2.
To increase the heating capacity.

In the above embodiment, the sub-capacitor 7 is a heat radiating passenger compartment heat exchanger, the expansion valve 9 is a decompressor, the evaporator 10 is a heat absorbing passenger compartment heat exchanger, and the electric motor 20 is a vehicle driving electric motor. The heater 30 constitutes heating means.

[0017]

As described above, according to the present invention, the waste heat of the cooling water of the drive system including the electric motor for driving the vehicle is recovered during the heating operation, and this heat passes through the heat exchanger for heat absorption inside the vehicle and the compressor. Since a heating means for raising the temperature of the refrigerant toward the intake side of the compressor is provided, even in a vehicle that uses an electric motor as a drive source, the waste heat of the cooling water in the drive system is effectively used to suppress an increase in the load on the compressor while heating. You can improve your ability.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a vehicle heat pump type air conditioner according to an embodiment of the present invention.

FIG. 2 is a pressure-enthalpy diagram for explaining the effect of the heater of the embodiment of FIG.

[Explanation of symbols]

 1 Compressor 5 Condenser 7 Sub-condenser 9 Expansion valve 10 Evaporator 20 Electric vehicle drive motor 21 Electric motor controller 30 Heater

Claims (1)

[Claims] 1. A heat-radiating vehicle interior heat exchanger through which a refrigerant compressed by a compressor is guided, a pressure reducer for expanding and decompressing the refrigerant that has passed through the heat-radiating vehicle interior heat exchanger, and a pressure reducing device that passes through this pressure reducer. In a heat pump type air conditioner for a vehicle equipped with an endothermic vehicle interior heat exchanger for absorbing heat, a waste heat of cooling water of a drive system including a vehicle driving electric motor is recovered during heating operation, and this heat is used to absorb the heat. A heat pump type air conditioner for a vehicle, comprising: heating means for increasing the temperature of the refrigerant passing through the vehicle interior heat exchanger toward the suction side of the compressor.