Throttle control apparatus for engines

摘要

A throttle control apparatus for engines comprises two throttle actuators for driving two corresponding main and sub throttle valves mounted in series in an intake pipe of an engine. An observer, to which the modern control theory is applied, presumes an opening degree of the main throttle valve in a normal condition, which occurs a predetermined time later, from an accelerator depression amount, which represents a throttle opening command, and an opening degree (angular position) of the main throttle valve. A failure detector quickly finds, from a deviation between the presumed opening degree of the throttle valve at the predetermined later time and an actual opening degree of the main throttle valve, that the main throttle valve has failed. When a failure occurs, the control of the sub throttle valve is started, making it possible to effect the throttle opening control with improved reliability.