Valve operating device for internal combustion engine with variable valve timing and valve-lift characteristic mechanism

摘要

A valve operating device for an engine having at least two engine valves per cylinder, the valve operating device enabling both valve timing and valve-lift characteristic to be varied depending on engine operating conditions, includes a camshaft, 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, a main rocker shaft supported on a cylinder head, a sub rocker shaft, and at least one rocker arm set. The rocker arm set includes a low-speed rocker arm having a first follower driven by the low-speed cam and oscillatingly supported by the main rocker shaft and mounting thereon the sub rocker shaft, and a high-speed rocker arm having a second follower driven by the high-speed cam oscillatingly supported by the sub rocker shaft. The second follower is closely juxtaposed to the first follower and located within a dead space defined in the outside of the engine valves included in the engine cylinder. The at least one rocker arm set includes two adjacent rocker arm sets disposed between the associated two cylinders adjoining to each other. One of the adjacent rocker arm sets has a symmetric shape with respect to the other. The low-speed rocker arm included in the one rocker arm set and the low-speed rocker arm included in the other rocker arm set are supported on the same divided rocker shaft member.