Steering: Description and Operation

NOTE: This vehicle is available either with standard power steering or with an optional speed-sensitive variable-assist power steering system.

COMPONENTS
The power steering system consists of these six major components. Power Steering Pump, Power Steering Gear, Power Steering Reservoir, Power Steering Supply and Pressure Hoses, and Power Steering Fluid Return Hose. Turning of the steering wheel is converted into linear travel through the meshing of the helical pinion teeth with the rack teeth. Power assist steering is provided by an open center, rotary type control valve. It is used to direct oil from the power steering pump to either side of the integral steering rack piston.

SPEED-SENSITIVE VARIABLE-ASSIST POWER STEERING
Available as an option on this vehicle, is a speed-sensitive variable-assist power steering system. This system is an electronically controlled, variable-assist type of power steering system. Speed-proportional, variable-assist power steering provides additional assist while the vehicle is stationary and at slow driving speeds. This additional power steering assist reduces the steering effort required by the driver for slow speed driving and parking maneuvers. Speed-proportional variable-assist power steering then provides less steering assist at highway speeds, to maintain the firm, responsive feel of the standard non speed-proportional variable-assist power steering system.

Road feel is controlled by the diameter of a torsion bar which initially steers the vehicle. As steering effort increases as in a turn, the torsion bar twists, causing relative rotary motion between the rotary valve body and valve spool. This movement directs oil behind the integral rack piston, which in turn, builds up hydraulic pressure and assists in the turning effort.