Patent ID: 6276320
Filing Date: 2001-08-21
Classification: F01L

Abstract:
A valve mechanism of an internal combustion engine having a cylinder with a pair of air-intake valves, comprising;a cam shaft having a pair of pause sections for holding the air-intake valves substantially in closing pause states, a first operation cam with a profile capable of causing the air-intake valve to perform opening-closing motion, a second operation cam with a profile capable of causing the air-intake valve to perform opening-closing motion, and a third operation cam with a profile capable of causing the air-intake valve to perform opening-closing motion with a larger lift compared to the first and second operation cams;a first drive rocker arm operatively connected to one of the air-intake valves and contacted with one of the pause sections of the cam shaft;a second drive rocker arm operatively connected to another air-intake valve and contacted with another pause section of the cam shaft;a first free rocker arm contacted with the first operation cam;a second free rocker arm contacted with the second operation cam;a third free rocker arm contacted with the third operation cam;a first connection switchover means for connecting and disconnecting the first drive rocker arm with the first free rocker arm;a second connection switchover means for connecting and disconnecting the second drive rocker arm with the second free rocker arm;a third connection switchover means for connecting and disconnecting the first driver rocker arm and the second driver rocker arm with the third free rocker arm; andat least one of the drive rocker arms being pivotally supported on a rocker arm shaft and operatively connected to the air-intake valve through a hydraulic tappet which is held by a hydraulic tappet holder fixed to a cylinder head of the engine, and the hydraulic tappet holder being formed with a recess positioned within a rocking range of the drive rocker arm and capable of receiving the drive rocker arm partially.