The automobile air conditioning compressor is the heart of the automobile air conditioning refrigeration system, which plays the role of compressing and transporting refrigerant steam. Compressors are divided into two types: non-variable displacement and variable displacement. According to different working principles, air conditioning compressor can be divided into fixed displacement compressor and variable displacement compressor.

According to the different working modes, compressors can generally be divided into reciprocating and rotary types. Common reciprocating compressors include crankshaft connecting rod type and axial piston type, and common rotary compressors include rotary vane type and scroll type.

Working principle classification

According to different working principles, air conditioning compressor can be divided into fixed displacement compressor and variable displacement compressor.

Constant displacement compressor

The displacement of the constant displacement compressor increases proportionally with the increase of the engine speed. It can not automatically change the power output according to the refrigeration demand, and has a great impact on the engine oil consumption. It is generally controlled by collecting the temperature signal of the evaporator outlet. When the temperature reaches the set temperature, the compressor electromagnetic clutch is released and the compressor stops working. When the temperature rises, the electromagnetic clutch is engaged and the compressor starts to work. The constant displacement compressor is also controlled by the pressure of the air conditioning system. When the pressure in the pipeline is too high, the compressor stops working.

Variable displacement air conditioning compressor

The variable displacement compressor can automatically adjust the power output according to the set temperature. The air conditioning control system does not collect the temperature signal of the evaporator outlet, but controls the compression ratio of the compressor according to the change signal of the pressure in the air conditioning pipeline to automatically adjust the outlet temperature. In the whole process of refrigeration, the compressor is always working, and the regulation of refrigeration intensity is completely controlled by the pressure regulating valve installed inside the compressor. When the pressure at the high pressure end in the air conditioning pipeline is too high, the pressure regulating valve will shorten the piston stroke in the compressor to reduce the compression ratio, which will reduce the cooling intensity. When the pressure at the high pressure end drops to a certain extent and the pressure at the low pressure end rises to a certain extent, the pressure regulating valve increases the piston stroke to improve the cooling intensity.