System for automatically controlling vehicle speed to desired cruise speed whose control function is inhibited when system for controlling a vehicular traction operates and method therefor

摘要

A system and method for automatically controlling a vehicle speed to a desired cruise speed are disclosed in which an opening angle of a first throttle valve is adjusted so that the vehicle speed coincides with a target vehicle speed at which the vehicle cruises. The cruise control for the vehicle speed through the first throttle valve is inhibited when an occurrence of a slip on a drive wheel is detected and a traction control by means of a traction controlling system such that a driving force of the vehicle is reduced through a second throttle valve disposed in series with the first throttle valve in an engine intake air passage is executed so that an effective traction control can be achieved without interference of both systems when the vehicle enters on a road surface having a very low friction coefficient.