System Outline

System Outline

The cruise control system is a constant vehicle speed controller in which control of the switch on the instrument panel makes it possible to automatically adjust the opening of the engine throttle valve without depressing of the accel pedal.

1. Set Operation
When the CRUISE SW is turned on and the SET SW is pushed with the vehicle speed within the set limit (Approx. 40 km/h, 25 mph to 200 km/h, 124 mph), a signal is input to TERMINAL CCS of the engine control module, and the vehicle speed at the time the SET SW is released is memorized in the ECU as the set speed.

2. Set Speed Control
During cruise control driving, the ECU compares the set speed memorized in the ECU with the actual vehicle speed input into TERMINAL SPD of the engine control module from the combination meter, and controls the throttle control motor to maintain the set speed.

When the actual speed is lower than the set speed, the ECU causes the current to the throttle control motor to flow from TERMINAL M+ of the engine control module to TERMINAL 2 of the throttle control motor to TERMINAL 1 to TERMINAL M- of the engine control module. As a result, the motor in the throttle control motor is rotated to open the throttle valve and the throttle cable is pulled to increase the vehicle speed. When the actual driving speed is higher than the set speed, the current to the throttle control motor flows from TERMINAL M- of the ECU to TERMINAL 1 of the throttle control motor to TERMINAL 2 to TERMINAL M+ of the engine control module.

This causes the motor in the throttle control motor to rotate to close the throttle valve and return the throttle cable to decrease the vehicle speed.

3. Coast Control
During cruise control driving, while the COAST SW is on, the throttle control motor returns the throttle cable to close the throttle valve and decrease the driving speed. The vehicle speed when the COAST SW is turned off is memorized, and the vehicle continues at the new set speed.

4. Accel Control
During cruise control driving, while the ACC SW is turned on, the throttle control motor pulls the throttle cable to open the throttle valve and increase the driving speed.

The vehicle speed when the ACC SW is turned off is memorized and the vehicle continues at the new set speed.

5. Resume Control
Unless the vehicle speed falls below the minimum speed limit (Approx. 40km/h, 25mph) after canceling the set speed by the CANCEL SW, pushing the RES SW will cause the vehicle to resume the speed set before cancellation.

6. Manual Cancel Mechanism
If any of the following signals is input during cruise control travelling, the cruise control is cancelled.
- Depressing the clutch pedal (Cruise control clutch SW off). "Signal is not input to TERMINAL FC of the ECU"
- Depressing the brake pedal (Stop light SW on). "Signal input to TERMINAL STP of the ECU"
- Pushing the CANCEL SW (CANCEL SW on). "Signal input to TERMINAL CCS of the ECU"
- Pushing the CRUISE SW off "signal input to TERMINAL CCS of the ECU".

7. Tap-Up Control Function
When the difference between the actual vehicle speed and the set speed is less than 5 km/h (3 mph), the set speed can be increased 1.6 km/h (1 mph) each time by operating the RES/ACC SW quickly within 0.5 seconds.

8. Tap-Down Control Function
When the difference between the actual vehicle speed and the set speed is less than 5 km/h (3 mph), the set speed can be lowered 1.6 km/h (1 mph) each time by operating the SET COAST SW quickly within 0.5 seconds.

9. Auto Cancel Function
A. If any of the following operating conditions occurs during cruise control operation, the set speed is erased, current flow to the magnetic clutch is stopped and the cruise control is released, (CRUISE SW turns off).

When this occurs, the ignition SW must be turned off once before the CRUISE SW will turn on.
- When abnormality is found in the stop light SW input circuit.
- When abnormality is found in the cancel circuit.

B. If any of the following operating conditions occurs during cruise control operation, the set speed is erased, current flow to the magnetic clutch is stopped and the cruise control is released. (CRUISE SW turn off).

When this occurs, the cancel state is cleared as the CRUISE SW will turn on again.
- When abnormality is found in electronic throttle parts.
- Open circuit in the stop light SW.
- Momentary interruption of vehicle speed signal.
- Short circuit in the stop light SW.

C. If any of the following conditions occurs during cruise control operation, the set speed is erased and the cruise control is released. (The power to the magnetic clutch is cut off until the SET SW is "ON" again.)
- When the vehicle speed falls below the minimum speed limit, approx. 40 km/h (25 mph)
- When power to the cruise control system is momentarily cut off.

10. Overdrive Control Function
The overdrive control may be cancelled if the vehicle travels on the slope during cruise control travelling. After the overdrive control has been cancelled it is decided that the slope is finished, the vehicle returns to the overdrive control mode again.