Constant-speed running control device for vehicles

Claim 1

A constant-speed running control device for a vehicle, comprising: a running speed sensing means which senses the running speed of the vehicle; an acceleration computing means which determines acceleration of the vehicle at specific periods of time from a running speed signal sensed by said running speed sensing means; a target speed setting means which sets a target speed in order in maintain a fixed target speed of the vehicle; a target speed signal generating means which generates said target speed; a speed deviation computing means which determines speed deviation between said running speed signal and said target speed signal; a throttle valve driving means which control a throttle valve of the vehicle; a controlled variable computing means which inputs an acceleration signal and a speed deviation signal and computes a controlled variable for controlling the throttle valve of the vehicle such that said running speed will correspond to said target speed; a constant-speed running start sensing means for sensing the start of constant-speed running by said target speed setting means; a time measuring means which measures a specific time from the time when this constant-speed running is started; and a controlled variable adjusting means which adjusts said controlled variable in accordance with said speed deviation signal and a time measuring information given from said time measuring means, unconditionally outputting said adjusted controlled variable to said throttle valve driving means when a specific time is not over, and similarly outputting a controlled variable to said throttle valve driving means when said speed deviation exceeds a specific value when said specific time is over, and outputting a non-adjusted controlled variable to said throttle valve driving means when said speed deviation decreases under said specific value.