POWER STEERING SYSTEMS ON EARLY SUBARUS PART 3

Steering Sensor Assembly

The Steering Sensor sends a steering frequency signal to the Signal Controller. The Steering Sensor consists of two components:

• Photo coupler.
• Sensor Plate with 60 slits.

As the sensor plate passes through the photo coupler it generates a pulse signal which is interpreted as steering frequency. A 360 degree turn equals 60 pulses. Four 90 degree movements also equal 60 pulses.

Note: The Signal Controller determines the difference between one full (360 degree) rotation of the steering wheel and four quarter (90 degree) turns based upon vehicle speed.

Signal Controller

The Signal Controller receives inputs primarily from the vehicle speed sensor and the steering sensor. It continuously monitors the driving conditions over any given 20 second time period.

Based upon an average of the vehicle speed and the steering frequency, it then determines the amount of power assist (duty ratio) required. This signal is then sent to the Power Controller which in turn operates the motor.

Power Controller

The Power Controller is the last major Cybrid steering component. It functions like a duty solenoid in order to control the electric current to the Motor/Pump assembly. The power controller regulates the ground circuit of the motor based upon input from the Signal Controller. A 100 percent duty equals maximum assist.