Noise And Vibration Characteristics Research Of Variable Displacement Automotive Air Conditioning Compressor

Variable displacement automotive air conditioning compressor with low Level in domestic development is replacing the market of fixed displacement compressors of automotive air conditioning, for its high speed, good reliability, and strong controllability. As the improving of Engine and transmission noise control levels, variable displacement compressor has increasingly prominent noise and vibration problems with it’s variable displacement and complex working environment.Based on noise and vibration experimental research methods, Careful study of the noise characteristics of variable displacement air conditioning compressor. Experimental research shows that the noise of compressor is larger than normal,the noise source is related to the moving parts of the compressor.What’s more,the compressor noise at idle condition sometimes is larger than the steady condition.In view of the noise of compressor is related to the moving parts like piston and so on,we conducted theoretical kinematics analysis and simulation analysis by Adams. The Swash plate angle and speed have great impact on the motion of Pistons and hemisphere of variable displacement swash plate type compressors,and the noise and vibration generated by swash plate,piston and hemisphere will contribute to the noise of compressors for the clearance between piston and hemisphere.Several sets of noise and vibration testing under different clearance between piston and hemisphere of compressor have conducted. Experimental research shows that the shock among pistons, hemisphere and swash plate is the main factor that the idling noise of compressor is too large. Especially at high speed,with the increasing of the clearance between the piston and the hemisphere,compressor noise at idling condition will also increase.A noise and vibration test of the compressor with shearing valves has conducted for the noise of measure point4which is close to valves of compressor is the largest. Experimental research shows that the proportion of noise caused by compressor valves’ movement of the intake and exhaust is very large when variable displacement air conditioning compressor at low speed.However, the proportion of noise caused by compressor valves is very small when variable displacement air conditioning compressor at high speed. The results of the research provide technical guidance for noise control method of compressor.