Compressor Clutch: Description and Operation
CLUTCH-A/C COMPRESSORDESCRIPTION
NOTE: Denso 10S17 A/C clutch assembly shown. Visteon HS-18 compressor similar.
The A/C compressor clutch assembly consists of a stationary electromagnetic field coil (4), bearing and pulley assembly (3), shims (7) and a clutch plate (2) that is splined to the compressor shaft and secured by a bolt (1). These components provide the means to engage and disengage the A/C compressor from the engine accessory drive belt.
The A/C clutch bearing and pulley assembly on both A/C compressors are retained to the front of the compressor with a snap ring (6). The A/C clutch field coil on the Denso 10S17 A/C compressor is also retained to the front of the compressor using a snap ring (5). The field coil on the Visteon HS-!8 compressor is pressed onto the front of the compressor.
OPERATION
The A/C compressor clutch components provide the means to engage and disengage the A/C compressor from the engine accessory drive belt. When the electromagnetic A/C clutch field coil is energized, it magnetically draws the clutch plate into contact with the clutch pulley and drives the compressor shaft. When the coil is not energized, the pulley freewheels on the clutch hub bearing, which is part of the pulley assembly.
A/C clutch engagement is controlled by the following:
- A/C-heater mode control
- A/C clutch relay
- A/C pressure transducer (gasoline engines)
- A/C high pressure switch (diesel engine)
- A/C low pressure switch
- Powertrain control module (PCM) or engine control module (ECM) (depending on application)
The A/C compressor clutch components cannot be repaired and, if faulty or damaged, they must be replaced.