To automatically adjust a vehicle speed to a prescribed preset vehicle speed, by respectively controlling speed increase ratio of a continuously variable transmission and action of an engine brake assist means, so that an actual vehicle speed detected by a vehicle speed detection means meets to a target vehicle speed for performing constant speed traveling.
Driving of an actuator 54 is controlled by an engine control unit 30 through a solenoid value. That is, this control unit 30 respectively controls speed increase ratio of a continuously variable transmission 5 and action of engine brake assist means 15, 16 so that an actual vehicle speed detected by a vehicle speed detection means 32 meets to a target vehicle speed for constant speed traveling. In this way, even in the case of constant speed traveling on a long descending road of steep slope in a condition of large loadage, the vehicle speed can be adjusted to a prescribed preset vehicle speed, the constant speed traveling can be performed.
KAWATANI SEI
NAKAYAMA SHINJI
