Patent ID: 6167852
Filing Date: 2001-01-02
Classification: F01L

Abstract:
A valve opening and closing time detecting apparatus for an electromagnetically operated valve (1) provided on a cylinder head (2) of an internal combustion engine having: a valve body (4) inserted in said cylinder head (2) for closing a port provided therein by tightly seating a valve head (4a) of said valve body (4) on a valve seat (12) and for opening said port by keeping said valve head (4a) away from said valve seat (12), an armature (17) provided on said valve head (4a) in a lift adjuster (8), a first coil (5) provided to surround a stem (4b) of said valve body (4) for opening said port by drawing said armature (17) against a closing force of a first spring (13), a second coil (6) provided on said armature (17) for closing said port by drawing thereof against an opening force of a second spring (19), and a crank angle sensor (21) for detecting a number of crank-shaft revolutions of said engine and for producing an r.p.m. signal, comprising: a vibration sensor (20) directly attached to said cylinder head (2) proximate to said first coil (5) for receiving only a vibration of said valve body (4) when said valve head (4a) contacts upon said valve seat (12), and reaches a maximum lifted position from said valve seat (12) while said engine is operating and for generating a vibration signal; trigger signal generating means (31) responsive to said r.p.m. signal and said vibration signal for storing threshold values of vibrations corresponding to each r.p.m. and for producing a trigger signal; and judging means (30) responsive to said vibration signal and said trigger signal for deciding exact closing and opening times of said valve (1) by comparing said vibration signal with said threshold values corresponding to a present r.p.m. so as to avoid receiving noises due to aging and manufacturing allowances of said valve (1) by an installation of said vibration sensor (20) in immediate vicinity of said valve.