Control method for refrigerant flow quantity in automobile air conditioning system and automobile air conditioning system

Abstract

The invention discloses a control method for the refrigerant flow quantity in an automobile air conditioning system and the automobile air conditioning system. The automobile air conditioning system comprises a compressor, a condenser, an internal heat exchanger and an evaporator and further comprises an electronic expansion valve which is installed between an outlet in a high-pressure side of the internal heat exchanger and an inlet of the evaporator. A controller transmits a control signal to the electronic expansion valve according to the pressure and temperature of an outlet in a low-pressure side of the internal heat exchanger, the electronic expansion valve receives the control signal to adjust the opening degree of the electronic expansion valve, and then the superheat degree of the outlet in the low-pressure side of the internal heat exchanger is controlled. In the other implementation mode, the controller transmits the control signal to the electronic expansion valve according to the pressure and temperature of the outlet in the high-pressure side of the internal heat exchanger, and then the super-cooling degree of the outlet in the high-pressure side of the internal heat exchanger is controlled. According to the superheat degree or the super-cooling degree, the flow quantity of refrigerant entering the evaporator is adjusted.

Description

technical field [0001] The invention relates to a method for controlling refrigerant flow in an automobile air-conditioning system and the automobile air-conditioning system. Background technique [0002] The replacement of refrigerant from the current R134a to R1234yf has become a major technical improvement measure in the field of automotive air conditioning. However, since the latent heat of R1234yf refrigerant is relatively low, direct replacement will reduce the cooling capacity of the system. Therefore, it is common practice to use an internal heat exchanger, the Internal Heat Exchanger (IHX), to increase the cooling capacity of the system. The internal heat exchanger is a heat exchanger connected between the compressor, the evaporator and the condenser, and its function is to use the refrigerant at the outlet of the evaporator to cool the refrigerant at the outlet of the condenser, so as to improve the subcooling at the outlet of the condenser to increase cooling ca...

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Problems solved by technology

[0006] Therefore, it is necessary to improve the problem that the thermal expansion valve in the prior art cannot accurately control the system flow and superheat

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