Cruise Control Actuator Operation


1.Motor and limit switch
The motor revolves either clockwise or counterclockwise in response to acceleration or deceleration signals from the cruise control ECU, thereby altering the opening angle of the throttle valve.
The motor will be damaged if it continues running after the throttle valve fully opens or closes. To prevent this, the motor has two limit switches, No.1 and No.2. When the throttle valve has fully opened after receiving an acceleration signal from the cruise control ECU, limit switch No.1 opens, stopping the motor. While, the throttle valve fully closes (deceleration), limit switch No.2 opens, stopping the motor. Both of the switch contacts are closed in between the position where the throttle valve fully opens and where it fully closes.
2.Magnetic clutch
This clutch engages and disengages the motor and the control arm during cruise control operation.
When the driver activates any of the cancel switches, or if any of the automatic cancellation conditions are made while driving under the control of the CCS, the cruise control ECU disengages the safety magnetic clutch to stop the operation of CCS.
When the brake pedal is depressed, the cruise control ECU receives the cancel signal and the cruise control ECU turns the magnetic clutch off.
At the same time, power supply to the safety magnetic clutch is mechanically cut off and the magnetic clutch is turned off.
When this clutch is turned off, the motor and the control arm become free.
The control arm, therefore, returns to the idle position, and control of the CCS is cancelled.
3.Potentiometer (some models only)
The potentiometer detects the rotational angle of the control arm and sends a signal to the cruise control ECU at all times informing it of this angle.
The cruise control ECU stores this data in its memory.
If a difference between the set speed and the actual vehicle speed thereafter occurs, the cruise control ECU determines how much the throttle opening angle should be changed to conform the set speed based on this data.
In the ETCS-i controlled type, the throttle control motor substitutes for the function of the cruise control actuator.
For the throttle control motor, refer to the TEAM21 Diagnosis Technician >> “Gasoline Engine Control System” book >> “Other Control Systems” chapter >> “ETCS-i (Electronic Throttle Control System-intelligent)” group.

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