Damper valve, component description - GF32.31-P-5112GZ

MODEL 164.1 /8 with CODE (489) Airmatic (air suspension with level adjustment and adaptive damping system ADS)

Front axle damping valve unit, shown on damping valve unit, left front axle

The vehicle contains 4 damping valve units, whereby one damping valve unit each is assigned to a wheel.

Fig 1: Identifying Left Front Axle Damping Valve Unit (Shown On Damping Valve Unit, Left Front Axle)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Rear damping valve unit, shown on left rear axle damping valve unit

Fig 2: Identifying Left Rear Damping Valve Unit (Shown On Left Rear Axle Damping Valve Unit)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Shown on left front axle damping valve unit

Design

The left front axle damping valve consists of a housing and a 2-piston reed-valve assembly. Located above are the spring-loaded solenoid valve pistons and the solenoids.

Valve pistons and solenoids each form the solenoid valve 1, left front and solenoid valve 2, front left.

Fig 3: Identifying Left Front Axle Damping Valve Unit Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Diagram using left front axle suspension strut

a, b, c and d form a unit each comprising a ball valve and throttle (diagram of a 2-piston reed-valve assembly).

Fig 4: Left Front Axle Suspension Strut Diagram

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Function

Actuation by the AIRmatic control unit (N51) enables 4 damping force settings to be achieved. The damping valves can be individually configured for each wheel.

Current regulation is performed using pulse width modulated actuation from the AIRmatic control unit with approx. 800 Hz. The control unit has 2 output stages per damping valve for actuating the solenoid valves (y1, y2).

An open circuit in the line to the individual damping valve units is recognized by the AIRmatic control unit.

Damping force setting 1

For comfortable rolling with small sprung mass vibrations and low longitudinal and lateral acceleration. With this damping force setting the solenoid valves are open so that most of the oil flows parallel to the hard rebound and compression stage of the operating piston via the softer reed valves on the solenoid valves. The comfort rebound and compression setting is therefore achieved.

Fig 5: Damping Force Diagram (Setting 1)

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Damping force setting 2

The reed valves at the valve piston generate a slightly firmer setting. If the body is lowered, solenoid valve 2 is opened and solenoid valve 1 is closed.

The reed valves (a = hard compression and b = soft rebound) at solenoid valve 1 generate a hard compression and a soft rebound.

Fig 6: Damping Force Diagram (Setting 2)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Damping force setting 3

The reed valves at the valve piston generate an even firmer setting. If the body is raised, solenoid valve 1 is opened and solenoid valve 2 is closed. The reed valves (c = hard rebound and d = soft compression) at solenoid valve 2 generate a hard rebound stage and a soft compression stage.

Fig 7: Damping Force Diagram (Setting 3)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Damping force setting 4

For increased driving safety with high longitudinal and lateral vehicle acceleration.

Solenoid valves 1 and 2 are closed. The reed valves (a = hard compression and c = hard rebound) generate a hard compression and rebound. All the oil flows via the hard rebound and compression of the operating piston.

These damping force settings are also engaged even if the ADS has any system errors.

Fig 8: Damping Force Diagram (Setting 4)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.