Cruise Control: Description and Operation

Construction Diagram (Auto-Cruise Control System):

System Diagram:

Components And Functions:

GENERAL DESCRIPTION
By using the auto-cruise control, the driver can drive at preferred speeds in a range of approximately 40 to 200 km/h (25 to 124 mph) without depressing the accelerator pedal.

Basically the system is the same as the previous type, but on A/T models the power control module (PCM) sends a vehicle signal to the auto-cruise control- ECU.



SET/COAST SWITCH FUNCTION

- SET
The vehicle speed at the moment the "SET" switch was switched from ON to OFF while driving within the limit vehicle speed range is memorized as the "set vehicle speed" and thereafter the actuator is controlled so that fixed- speed driving at that speed is possible. However, if this "SET" operation was made while driving at a speed higher than the high speed limit, the high speed limit speed is memorized as the "set speed" and the actuator is controlled to maintain that speed.

- COAST
While the "COAST" switch is held ON during auto-cruise driving, the vehicle keeps decelerating. If the "COAST" switch is turned OFF before the vehicle speed decreases to 40 km/h (25 mph), the vehicle runs at the fixed speed at the moment the switch is turned OFF. If the "COAST" switch is turned OFF after the vehicle speed decreases to less than 40 km/h (25 mph), the auto-cruise control is cancelled.


RESUME/ACCELERATING SWITCH FUNCTION

- RESUME
When the fixed speed driving is cancelled by the conditions given in "CANCEL FUNCTION" switching the "RESUME" switch from OFF to ON while driving at a speed higher than the set speed causes the vehicle to be driven at a fixed speed which is the memorized speed just before cancelling.

- ACCELERATING
While the "RESUME" switch is ON during fixed speed driving, the vehicle is accelerated with the target acceleration. The vehicle speed at the moment the switch is turned OFF is then memorized and thereafter the vehicle is controlled for fixed speed driving at this speed. When the "RESUME" switch is ON, the vehicle may be accelerated to speeds above the high-speed limit but after the "RESUME" switch is turned OFF, the vehicle is thereafter controlled to drive at this speed.

CANCEL FUNCTION
When any of the following conditions occur, the power supply to the motor-driven negative pressure pump is shut off and the auto-cruise control is cancelled.

1. "CANCEL" switch ON
2. Stoplight switch ON (brake is applied)
3. Clutch pedal position switch ON
4. Park/neutral position switch ON
5. Vehicle speed at the low-speed limit [about 40 km/h (25 mph)] or lower
6. Vehicle speed going lower than memorized speed by 15 km/h (9 mph) or more
7. Vehicle speed once increasing to memorized speed less 10 km/h (6 mph) and then decreasing more than 15 km/h (9 mph) during
8. Vehicle speed changing sharply
9. Stoplight switch input (malfunction or open circuit)


HIGH-SPEED LIMIT FUNCTION
The vehicle cannot be driven at a fixed speed which is at or higher than the high speed limit [about 200 km/h (124 mph)]. When the "SET" switch is pressed while travelling at a speed above the high speed limit, a speed of about 200 km/h (124 mph) is memorized. Then when the accelerator pedal is released to decrease the vehicle speed (to a speed below the high speed limit), the auto-cruise control comes into action and the vehicle is controlled to travel at 200 km/h (124 mph).