Patent ID: 7469668

Claim:
An engine valve operating system, comprising a valve lift-changing mechanism ( 33 ) for continuously changing the lift amount of a valve ( 19 ), said valve lift-changing mechanism ( 33 ) being capable of adjusting a tappet clearance in accordance with a change in lift amount of the valve ( 19 ), wherein said valve lift-changing mechanism ( 33 ) includes a rocker arm ( 63 ) having a valve abutment ( 70 ) abutting against a stem end of the valve ( 19 ) and a cam abutment ( 65 ) abutting against a valve-operating cam ( 69 ), a first link ( 61 ) pivotally supported at one end on the rocker arm ( 63 ) at a first fulcrum ( 64 ) and at the other end on an engine body ( 29 ) at a second fulcrum ( 67 ), a second link ( 62 ) pivotally supported at one end on the rocker arm ( 63 ) at a third fulcrum ( 66 ) and at the other end on the engine body ( 16 ) at a fourth fulcrum ( 68 a ), and a crank member ( 68 ) for swinging the fulcrum ( 68 a ) for pivotally supporting said other end of at least one ( 62 ) of the first and second links ( 61 , 62 ) about an axis (C 2 ) parallel to an axis of rotation of a valve-operating cam ( 69 ), said axis (C 2 ) about which the crank member ( 68 ) is swung being eccentric (by δ) with respect to an axis (C 1 ) of the fulcrum ( 66 ) for pivotally supporting said one end of said at least one link ( 62 ).