Control apparatus in a motor vehicle for controlling a throttle valve on

Abstract

A control apparatus with a fail-safe function not only serves to enhance acceleration performance of a motor vehicle but also prevents a runaway upon occurrence of a failure in a throttle control system. An accelerator pedal actuation detector detects a magnitude of depression of an accelerator pedal by the driver. A vehicle speed detector detects a running speed of the vehicle. A gear ratio detector detects a gear ratio or gear position of a transmission. A plurality of target throttle opening patterns representing relations between target values of throttle opening degree and depression magnitudes of the accelerator pedal are stored in a memory. A first controller selectively determines an optimum target throttle opening pattern on the basis of the vehicle speed and the gear ratio to thereby control a throttle actuator for actuating a throttle in accordance with the selected pattern. An intake air quantity detector detects a quantity of intake air fed to an engine of the motor vehicle. A comparator compares a target intake air quantity determined on the basis of the depression magnitude of the accelerator pedal and an actual intake air quantity. When the actual intake air quantity is substantially greater than the target one, a second controller reduces the engine output power by temporarily stopping the fuel supply to the engine or by temporarily halting operations of some engine cylinders.