Vehicle speed control apparatus

Abstract

A vehicle speed control apparatus is provided which includes a vehicle speed sensor, a setting switch, a memory, a comparator, a timer, a quick responser and an actuator. The vehicle speed sensor detects and outputs the actual vehicle speed into the memory and the comparator. A driver operates the setting switch when the actual vehicle speed equals the desired vehicle speed. The setting switch outputs an initial signal for automatic control of the vehicle speed to the memory and the quick responser. The value of the desired vehicle speed is set in the memory which outputs a desired vehicle speed signal to the comparator and the timer. The comparator determines a difference between the actual vehicle speed and the desired vehicle speed, and outputs a manipulation signal into the actuator in accordance with this difference. When the quick responser receives the initial signal from the setting switch it outputs a maximum value signal to the actuator during a time period which is set in the memory according to a relationship between desired vehicle speed and time period. The actuator opens a throttle valve to a maximum degree during this time period. The timer receives the desired vehicle speed signal from the memory, and counts down the corresponding time period. When the time period has passed and the timer reaches `Zero`, the timer outputs an end signal to the quick responser. The actuator then adjusts the opening degree of the throttle valve according to the difference between the value of the desired vehicle speed and the value of the actual vehicle speed. This provides automatic control of vehicle speed without large initial decreases or increases in vehicle speed.