Steering: Description and Operation

The Steering Wheel Rotation Sensor is an optical sensor that provides steering wheel rotation rate (in rpm) to the Air Suspension/EVO Steering Module. With a rotation rate below 15 rpm. the Module uses only the vehicle speed input to determine the amount of power assist. If rotation rate exceeds 15 rpm. the rotation rate input causes the Module to boost power assist. At rotation rates of 100 rpm and above, full power assist is provided. regardless of vehicle speed.

Vehicle Speed Sensor (VSS)

The Vehicle Speed Sensor (VSS) provides the Module with vehicle speed information. The Module uses this input to control the EVO Actuator. which controls power assist. With vehicle speed between 0 and 5 mph. full assist is provided. As speed increases from 6 to 80 mph. power assist gradually decreases. Above 80 mph. little power assist is provided.

MODULE OUTPUTS

EVO Actuator

The EVO Actuator is mounted on the power steering pump and controls power assist by regulating the flow of power steering fluid in the pump. When maximum assist is required. the Actuator allows full fluid flow. When the Module determines that the power assist level should decrease. it powers the Actuator to reduce fluid flow.

The Variable Orifice Power Steering System has a built-in "fail safe" feature. An electrical malfunction will cause the Actuator to provide full power assist at all times.