ECO valve

The ECO valve is secured to the power steering pump. ECO means: Electronically Controlled Orifice.

The power steering pump is controlled by the ECO valve as needed. The ECO valve regulates the volumetric flow of the hydraulic fluid, thus regulating the pump's hydraulic power. A tandem pump can be installed depending on the equipment (active steering, Dynamic Drive).

A modern rack and pinion power steering gear generates high angular wheel speed (wheel is turned faster). The hydraulic must have the corresponding high performance for the high angular wheel speeds. A sufficiently dimensioned conventional vane-type compressor would generate a high power loss. The fuel consumption would be increased unnecessarily. An improvement can be yielded with a controllable power steering pump. The ECO valve in the power steering pump regulates the volumetric flow depending on the requirement and lowers the ram pressure in the hydraulic system.

In this way, the ECO valve affects the power consumption of the power steering pump. Fuel consumption and carbon dioxide emissions (CO2) from the vehicle's engine are reduced accordingly.

The nominal current for the ECO valve is specified to the Servotronic control unit by the Integrated Chassis Management (ICM). Exception: For vehicles of the M GmbH, the DME specifies the nominal current. The nominal current varies between 0 mA (minimum) in 860 mA (maximum).

Fig 1: Identifying Power Steering Pump, ECO Valve And Plug Connection

Courtesy of BMW OF NORTH AMERICA, INC.