According to the different working principles, air conditioning compressors can be divided into fixed displacement compressors and variable displacement compressors.
Fixed displacement compressors
The displacement capacity of the fixed-displacement compressor is proportionally increased with the increase of the speed of the engine, and it cannot automatically change the power output according to the needs of refrigeration, and the impact on the engine fuel consumption is relatively large. Its control is generally 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 combines and the compressor starts working. Fixed displacement compressors are also controlled by the pressure of the air conditioning system, and when the pressure in the line is too high, the compressor stops working.
Variable displacement air conditioning compressor
The variable displacement compressor automatically adjusts 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 pressure change signal in the air conditioning pipeline to automatically adjust the air outlet temperature. In the whole process of refrigeration, the compressor is always working, and the adjustment of refrigeration intensity completely depends on the pressure regulating valve installed inside the compressor to control. When the pressure at the high pressure end of the air conditioning line is too high, the pressure regulating valve shortens the piston stroke in the compressor to reduce the compression ratio, which reduces the refrigeration strength. 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 refrigeration strength.
