Patent ID: 6340010
Filing Date: 2002-01-22
Classification: F01L

Abstract:
A valve operating device for an internal combustion engine having at least two engine valves per cylinder, said valve operating device enabling both valve timing and valve-lift characteristic to be varied depending on engine operating conditions, comprising:a camshaft adapted to be driven by a crankshaft; at least one cam pair including a low-speed cam and a high-speed cam, each operating an associated valve of at least two engine valves included in a cylinder, the cam pair being formed on said camshaft; a main rocker shaft supported on a cylinder head, the main rocker shaft comprising a plurality of divided rocker shaft members supported on the cylinder head and including relatively short endmost rocker shaft members respectively located closer to both ends of the engine and relatively long intermediate divided rocker shaft members each being disposed between associated two cylinders adjoining to each other; at least one rocker arm set including: (a) a low-speed rocker arm having a first follower driven by the low-speed cam for operating the associated valve during a low-speed cam operating mode and supported by said main rocker shaft; and (b) a high-speed rocker arm having a second follower driven by the high-speed cam for operating the associated valve during a high-speed cam operating mode and mounted on the low speed rocker arm, the second follower of the high-speed rocker arm being closely juxtaposed to the first follower and located within a dead space defined in an outside of the at least two engine valves included in the engine cylinder; and a mode switching device provided for switching from one of the low-speed and high-speed cam operating modes to the other depending on the engine operating conditions, said mode switching device initiating the low-speed cam operating mode by disconnecting the low-speed rocker arm from the high-speed rocker arm, and initiating the high-speed cam operating mode by connecting the low-speed rocker arm to the high-speed rocker arm.