1. According to its structure, positive displacement compressors can be divided into reciprocating piston type (referred to as reciprocating type) and rotary piston type (referred to as rotary type).
Both reciprocating and rotary types are used to varying degrees in automotive air conditioners. The reciprocating type was the earliest and is still widely used so far, (for example: BOCK, BITZER compressors). As far as reciprocating compressors are concerned, the technology is relatively mature, and they have accumulated rich experience in production and use. The material requirements are low, the processing is easy, and the cost is low. It can adapt to a wide range of pressure and cooling capacity, and has high thermal efficiency. The disadvantage is that due to the reciprocating operation of the piston, the dynamic balance performance is poor, which limits the increase of the compressor speed, the structure is complex, the wearing parts are many, and the maintenance workload is large. The working volume of the rotary compressor rotates and has no reciprocating mechanism, so the dynamic balance performance is good, the operation is stable, the vibration is small, and it has high efficiency within its suitable working range. In addition, the rotary compressor has simple structure, small volume, light weight, few parts and high reliability. However, the rotary compressor has a small displacement and is generally used in air conditioning systems with small cooling capacity, such as car air conditioning systems.
2. The driving mode of automobile air-conditioning compressor can be divided into two types according to its driving source, non-independent and independent.
The non-independent type is driven by the main engine of the car to drive the compressor. This driving method is suitable for models with more than the main engine of the car and the compressor power is not too large, such as cars, vans, engineering vehicles, etc. This driving method takes up less space and is easy to maintain. However, since the compressor consumes part of the power of the main engine, it will affect the acceleration performance of the vehicle, and the cooling capacity of the air conditioner will change with the speed of the vehicle.
Independent (or auxiliary), that is, an engine is separately configured to drive the compressor. Due to the separate special drive, the driving of the car and the cooling effect of the air conditioner do not affect each other. However, this driving method takes up a certain amount of car space, has high cost, high noise, and complicates the maintenance of the auxiliary engine, so the application range is not wide.
Regardless of whether it is driven by the main engine or the auxiliary engine, the automotive air-conditioning compressor is of an open type, that is, the power input end of the compressor main shaft extends out of the body and is connected to the driver through a pulley. The shaft extending out of the body is equipped with a shaft seal to prevent the refrigerant from leaking out.
