Front And Rear Valve Blocks: Compressor

The compressor is used to supply air pressure to the air suspension reservoir. The CHCM monitors the pressure within the reservoir and, when the engine is running, maintains a pressure of 16.5 bar gage.

The compressor comprises a motor driven two-stage piston assembly which operates in cylinders at opposite ends of the compressor body. The motor rotates a crank which moves the pistons up and down in their cylinder bores. The low-pressure cylinder delivers intermediate compressed air to the high-pressure cylinder on the down stroke. The high-pressure piston delivers fully compressed air with the up stroke which is passed, via the delivery valve, through the air dryer and into the air suspension system.

The cylinder head is fitted with a temperature sensor. The sensor is connected to the CHCM which monitors the cylinder temperature and can suspend compressor operation if an overheat condition occurs.

The following table shows the control module operating parameters for the differing air supply unit functions and the permitted compressor cylinder head operating temperatures.