Cruise Control: Description and Operation

System Outline

The cruise control system allows the driver to control the vehicle speed at a constant speed, such as on a high way, without depressing the accelerator pedal. By operating the SW, the engine throttle valve is automatically adjusted to control the vehicle speed at a constant speed.

1. SET OPERATION
The actual vehicle speed is compared with the memorized vehicle speed, and when the actual vehicle speed is faster than the memorized speed, a signal is output to rotate the electronic throttle motor to close the throttle valve. When the actual vehicle speed is slower than the memorized speed, a signal is output to rotate the electronic throttle motor to open the throttle valve.

2. SET SPEED CONTROL
While traveling (Within the set speed limit) with the CRUISE SW on (Power indicator on), the speed when the SET/COAST SW is operated to off is memorized and the vehicle is controlled at that speed.

3. COAST CONTROL
When the SET/COAST SW is operated to on during cruise control driving, the cruise control opening angle requirement is controlled to 0 to decrease the vehicle speed (However the throttle valve itself is not fully closed due to ISC etc.), and the speed when the SW is operated to off is memorized, and the vehicle is controlled at that speed. Furthermore, every time the SET/COAST SW is operated to on momentarily (Approximately 0.5 seconds), the memorized vehicle speed is decreased by approximately 1.5 km/h. In case of tap down operation where the difference between the memorized vehicle speed and the actual vehicle speed is more than 5 km/h, the speed when the SW is operated to off is memorized, and the vehicle is controlled at that speed.

4. ACCEL CONTROL
When the RES/ACC SW is operated to on during cruise control driving, the electronic throttle motor is rotated so that the throttle valve opens to increase the vehicle speed, and the speed when the SW is operated to off is memorized, and the vehicle is controlled at that speed. Furthermore, every time the RES/ACC SW is operated to on momentarily (Approximately 0.5 seconds), the memorized vehicle speed is increased by approximately 1.5 km/h,
In case of tap up operation where the difference between the memorized vehicle speed and the actual vehicle speed is more than 5 km/h, the memorized speed will not be changed.

5. MANUAL CANCEL MECHANISM
If any of the following signals are input during cruise control driving, the current to the motor flows in the direction to close the throttle valve, and the cruise control is canceled. (Vehicle speed memory will not be not erased)
- Stop light SW is on (Brake pedal is depressed)
- D position circuit in the Park/Neutral position SW is turned from on to off (Shift position is changed from D to N, 2, or 1) (A/T)
- The cruise control clutch SW is on (Clutch pedal depressed) (M/T)
- The CANCEL SW of the control SW is on
- The CRUISE SW is off (Vehicle speed memory will be erased)
- Shift lever in M position and shift range other than D or 3 position (A/T)

6. RESUME CONTROL
After canceling the cruise control (Except when the CRUISE SW is off) if the vehicle speed is above the minimum speed limit (Approximately 40 km/h, 25 mph) operating the RES/ACC SW from off to on will cause the system to accelerate to resume the vehicle speed before manual cancellation.

7. OVERDRIVE CONTROL FUNCTION
During cruise control driving, the overdrive may be cut on an uphill grade.
After the overdrive is cut, if the vehicle speed reaches the overdrive resume speed (Set speed minus 2 km/h), and if the system determines that the uphill grade has finished, the overdrive will resume after overdrive resume timer operation. However, if the actual vehicle speed becomes slower than the overdrive resume speed before the timer operation has finished, the timer will be reset, and will start again when the vehicle speed reaches the overdrive resume speed.

8. AUTO CANCEL OPERATION
1. If any of the following conditions are detected, the set speed is erased and the control is canceled.
At this time, the power indicator will blink, and control of the system will be prohibited until the CRUISE SW is turned on again.
- Disconnection and/or short in the stop light SW
- Failure in the vehicle speed signal
- Failure in the electronic throttle parts
2. If any of the following conditions are detected, the set speed is erased and the control is canceled.
At this time, the power indicator will blink, and control of the system will be prohibited until the ignition SW is turned off.
- Failure in the stop light SW input circuit
- Failure in the cancel circuit.
3. If any of the following conditions are detected, the set speed is erased and the control is canceled. (Reset is possible)
- The actual speed becomes slower than the minimum speed limit.
- The actual speed becomes -16 km/h slower than the set speed.