Patent ID: 6065447
Filing Date: 2000-05-23
Classification: F02M

Abstract:
An idle speed control device for internal combustion engine, having an auxiliary intake air passage by-passing a throttle valve provided in a main intake air passage of an internal combustion engine and communicating an upstream side and downstream side of said throttle valve, a valve body measuring a flow rate of auxiliary air flowing in said auxiliary intake air passage and a driving device for driving said valve body, whereinsaid valve body comprisesa shaft moved forward and backward in an axial direction by said driving device,a valve portion fitted on one end portion of said shaft for opening and closing said auxiliary intake air passage by forward and backward movement of said shaft in cooperation with a valve seat provided in said auxiliary intake air passage, a diaphragm of which an inner peripheral portion is held by a plate fixed to said shaft and an outer peripheral portion is mounted on a member forming said auxiliary intake air passage,a partition wall provided between said valve portion and said diaphragm and forming a part of a wall surface of said auxiliary intake air passage,a spring of which one end abuts said partition wall and the other end abuts said plate, said spring urging said valve portion so as to open with smaller force than a negative pressure generated downstream of said throttle valve during running of the engine.