Electronic air suspension

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The electronic air suspension is an electronically controlled system in the commercial vehicle sector in order to keep a vehicle at a certain level regardless of the load condition.

construction

Distance sensors

The distance sensors are installed between the chassis and the body and have the task of determining the distance between them. They mainly consist of a potentiometer and a mechanism that transfers the movements of the axis to the potentiometer.

Control block

The control block is the central unit for filling and venting the air suspension bellows . For this purpose, several solenoid valves are arranged in a housing . The electronic commands from the control unit are implemented here.

Control unit

The control unit is the center of the air suspension system. This is where all information comes in and is processed. The parameters stored here determine the individual functions of the system.

Pressure sensors

They measure the pressure in the air suspension bellows and report it to other vehicle systems, e.g. B. via a CAN data bus. They are not installed in every system.

Controls

The main control element is a switch on the dashboard with which the lowering and raising process can be initiated. A key switch enables the system to be switched off completely.

Mode of action

The control block is constantly supplied with compressed air from the vehicle's compressed air system. A suitably sized air tank stores a sufficient supply under a pressure of at least 10  bar .

If the vehicle is loaded, it sinks down and the control unit measures a changed voltage on the distance sensors. This is compared with the stored reference values. In order to reach the originally set normal level again, the air bags must now be subjected to higher pressure so that the vehicle is lifted. The control unit now controls the corresponding solenoid valves in the control block. These allow the supply pressure to flow into the air bags. The control unit continuously determines the vehicle level via the distance sensors and adjusts it until the desired height is reached.

If the vehicle is unloaded, the control unit will vent the air suspension bellows until the normal level is reached again.

Areas of application

The electronic air suspension is preferably installed in low-floor buses , as it is possible to lower the vehicle on the entry side ( kneeling ) to make it easier for passengers to get on. Electronic air suspension is also used in heavy trucks and their trailers, as well as in cranes . In the passenger car range, it is not very often used. Only upper-class vehicles, " SUVs " and off-road vehicles occasionally use air-sprung chassis, which are usually subject to a surcharge.