Pressure supply function - GF32.22-P-4010B

MODEL 215, 220 with CODE (487a) Active body control (ABC) 

Fig 1: Identifying Pressure Supply Components

In normal driving mode ABC works at a pressure between 180 to 200 bar.

A radial piston pump (1) is used for the pressure supply. Like the power steering pump it is part of the tandem pump and is driven directly by the engine via a single-belt drive.

The hydraulic fluid is drawn out of the oil reservoir (2). An Active Body Control (ABC) suction restrictor valve (Y86/1) attached to the pump regulates the intake quantity and with it the pressure. The quantity of oil is determined depending on the driving situation. The oil is delivered to the pressure supply valve unit (52) by the pump. A pulsation damper (52a) attached to this valve unit compensates the hydraulic system vibrations. A pressure limiting valve in the valve unit prevents a pressure increase above 200 bar. Pressure peaks are led directly into the return flow and reduced.

The system oil pressure is monitored by the pressure sensor (B4/5). Downstream of the pressure supply valve unit (52) the pressure is led to the ABC front/rear axle valve units (Y36/1, Y36/2). There the oil is supplied to the actuating cylinders in the suspension struts (40, 41) depending on demand. 2 pressure reservoirs ensure the system pressure when there is a higher oil demand.

Surplus oil flows back through the return flow lines into the oil reservoir (2) via an oil cooler (9) and an oil filter (2a). A return flow reservoir to take up the oil flowing back and to reduce the pressure peaks is also attached to the return flow.

An ABC oil temperature sensor (B40/1) in a distributor in the return flow measures the temperature of the oil. A preload valve is housed in the same distributor which ensures a minimum pressure of 10 bar in the return flow when the engine is running.