PURPOSE:To diminish car speed undershoot fluctuations by starting normal duty ratio control after setting the duty ratio at the maximum level for a fixed time when a newly stored car speed after override is faster than the originally stored speed by more than a fixed speed range. CONSTITUTION:A vacuum actuator 6, which controls opening angle of a throttle valve via an accelerator-link accoriding to an axial movement of output rod (6h) is equipped with a control valve (6a) and a release valve (6b) electrically controlled via drivers 5, 7. The drivers 5, 7 are controlled by a micro-computer 1 in response to a pulse signal with duty ratio corresponding to deviation be tween a car speed detected by a speed sensor 2 and a stored car speed fixed and memorized through operation of a set switch 4. In this case, during override when a stored speed is reset under a condition in which the car speed exceeds a stored speed by a certain speed range, it is controlled in such a way that normal duty ratio control starts after setting me duty ratio at the maximum level for a fixed time.
展开▼
