Fail-safe intake air flow control system for internal combustion engine

摘要

An intake air flow control system for an internal combustion engine of a motor vehicle comprises an accelerator pedal depression sensor for detecting depression depth of an accelerator pedal, a throttle actuator for regulating opening degree of a throttle valve in dependence on the depression depth of the accelerator pedal, a bypass intake passage which bypasses an intake pipe at a location where the throttle valve is disposed, a bypass control valve installed in the bypass intake passage, an abnormality detector for detecting abnormality of control of the throttle actuator, and a controller for controlling the opening degree of the bypass control valve in dependence on depression depth of the accelerator pedal in response to detection of abnormality of in the control performed through the throttle actuator. Operation of the engine can be fail-safed even upon occurrence of failure in the throttle control system in the fully closed state of the throttle valve.