involves models: FAW – Volkswagen Jetta sedan, the use of air-conditioning compressor Shanghai Sanden Behr Automotive Air Conditioning Co., Ltd. (factory code is 5BL) production.
Content Bulletin: air after the A / C switch off air conditioning compressor is sent ldquo; call, call rdquo; sound, the principle of which will now be described generated.
(1) equipped with a car speed Proton external control type swash plate variable displacement air conditioning compressor, which follows the operation of the engine through a torque limiter synchronization. Change displacement compressor, an electric signal is conveyed to the compressor unit control solenoid valve is achieved by controlling the air conditioning system of the vehicle, the compressor is also operated at the minimum displacement even if the A / C switch is not turned on.
(2) OFF mode includes two cases: one is closed A / C switch after use air conditioner, the other is not turned on A / C switch. Close A / C switch is OFF mode of the air conditioner compressor from large displacement to the minimum displacement Save the work process, is not turned OFF mode A / C switch is at a minimum displacement state of the compressor work. When the A / C switch is turned off, the compressor control solenoid valve current rapidly drops to zero, the internal angle of the swash plate compressor will be gradually reduced, the level of the system pressure gradually restore balance. Pulsation in the air conditioning system pressure balance in the process, always with the operation of the compressor shaft engine is running, the spindle will produce periodic internal pressure, ldquo; call, call rdquo; a sound that is external manifestations pulse, but with pressure-balanced end, the sound will also weaken.
(3) the environmental conditions (ambient temperature, engine speed, set by the user and the air-conditioning control panel face velocity) and system conditions (the amount of refrigerant charging, refrigeration oil, piping and a control signal response time ) will affect the a / C switch off size periodic pressure pulsation pressure balance the system time required, and the pressure balancing process, so that different models of the same or different vehicle models, ldquo; call, call rdquo; sound presence time and size will be differences, this sound is due to the structural characteristics of the external control type variable displacement compressor (synchronous spindle is always to follow the engine running and displacement by external control to change electrical signals) the decision will not affect the normal compressor work and life.
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