Method for controlling by-pass air flow on deceleration of internal combustion engine

Abstract

Described herein is a method for controlling the bypass air flow of internal combustion engine, which prevents the air-fuel ratio from becoming over rich temporarily in the initial stage of deceleration of the engine by driving a control valve to open a throttle by-pass passage on deceleration of the engine to supply auxiliary air thereto and which includes: detecting the open angle of the throttle valve; setting a valve opening rate according to the throttle open angle; setting an upper limit on the valve opening rate when it is greater than an upper limit value determined in relation with the engine speed; driving the control valve according to the valve opening rate; and on deceleration of the engine, gradually reducing a valve opening rate set in an operation prior to the deceleration.

Dependencies are inferred from the claim text.