Principles of Operation
The speed control system is designed to maintain a selected vehicle speed between 48 and 200 km/h (30 and 125 mph).
The electronic stepper motor (internal to the speed control actuator) is controlled by turning the three phases of the motor ON and OFF in sequence. The sequence determines the motor direction (open throttle or closed throttle based on vehicle speed)
The brake pedal position (BPP) switch is a normally open switch. When the brake pedal is applied with the speed control system engaged, the BPP switch closes, putting the speed control in stand-by mode.
Normally, when the brake pedal is applied, the speed control actuator deactivates the speed control system. Under increased brake pedal effort, the deactivator switch, a normally closed switch, will open and remove power to the speed control actuator clutch, releasing the throttle independent of the speed control actuator.
The clockspring provides the electrical interface between the steering column wiring and the speed control switches in the steering wheel.
The inputs to the speed control actuator are:
- Vehicle speed signal
- Speed control switches
- BPP switch
- Deactivator switch
The output of the speed control actuator is:
- Speed control cable controlled throttle position