Suspension Air Supply Unit

Air is exhausted from the system by opening the exhaust valve. Lowering the suspension is achieved by opening the required air spring valves and the exhaust valve. The compressor operates to pressurize or to inflate 1 or more of the air springs.

The compressor will not operate when the engine is not running and the engine is not ECO stopped, unless under control of a Jaguar Land Rover approved diagnostic equipment.

There are a number of conditions that will inhibit operation of the suspension air supply unit.

Electric Motor 

The electric motor is a 12V Direct Current (DC) motor with a nominal operating voltage of 13.5V. The motor drives a crank which has an eccentric pin to which the 2 stage piston assembly is attached.

Air Suspension Compressor 

The air suspension compressor comprises a motor driven 2 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 (LP) cylinder delivers intermediate compressed air to the High Pressure (HP) cylinder on the down stroke. The HP piston delivers fully compressed air with the up stroke which is passed, via the delivery valve, through the air drier and into the air suspension system.

Air Suspension Air Drier 

Attached to the air suspension compressor is the air drier which contains a desiccant for removing moisture from the compressed air. Pressurized air is passed through the air suspension air drier which removes any moisture in the compressed air. Then the compressed air is passed into the air suspension system.

When the air springs are deflated, the exhaust air passes back through the air drier, removing the moisture from the unit and regenerating the desiccant.

The air drier is an essential component in the system that makes sure only dry air is present in the system. If moist air is present, freezing can occur resulting in poor system operation or component malfunction or failure.

In order for the air suspension air drier to work correctly the affected air springs must be deflated before servicing. When the air springs are deflated the connections that hold the air in these components can be removed.

Exhaust Valve 

The exhaust valve operates when the pilot exhaust valve is opened, allowing air to be exhausted quickly.

The pilot exhaust valve is connected to the air delivery gallery, downstream of the air drier. The pilot exhaust valve, when opened, operates the slave exhaust valve, allowing air to exhaust the system.

When the solenoid is energized, pilot exhaust air moves the slave exhaust valve plunger. The slave exhaust valve plunger allows the pressurized air from the air suspension system to pass through the air drier to the atmosphere.