Patent ID: 7409936
Filing Date: 2008-08-12
Classification: F01L,F02D

Abstract:
1. A cam phase detecting apparatus for an internal combustion engine provided with a variable valve timing mechanism which changes a rotation phase of a camshaft relative to a crankshaft to vary valve timing of an engine valve, comprising: a cam angle detector that outputs a cam angle signal indicating a rotational position of said camshaft; a crank angle detector that detects a rotational position of said crankshaft to output a reference angle signal at each crank angle corresponding to a stroke phase difference between cylinders of said internal combustion engine; a measuring section that measures a phase difference between said cam angle signal and said reference angle; and a rotation phase detector that detects the rotation phase of said camshaft based on the phase difference measured by said measuring section, wherein: said cam angle detector is configured to arrange detectable portions for being detected on a rotation member that is capable of being rotated in association with said camshaft, said detectable portions being disposed at equiangular intervals, by numbers which are an integer n (n≧2) times a number of cylinders, each having the engine valve driven by said camshaft, said detectable portions being detected by a sensor to thereby output said cam angle signal, so that said cam angle signals, the number of which are the integer n (n≧2), are output in each generating interval of said reference angle signals, said measuring section measures a phase difference between a generation timing of said reference angle signal and each generation timing of subsequently outputted cam angle signals, the number of which are the integer n (n≧2 ), and said rotation phase detector detects the rotation phase several times in each generation interval of said reference angle signals, by detecting the rotation phase of said camshaft at every time said cam angle signal is generated, based on the phase difference of each output of said cam angle signals measured by said measuring section.