Patent ID: 7357107

Claim:
A valve system for an internal combustion engine, comprising: an intake-side rocker shaft; an exhaust-side rocker shaft; intake-side rocker arms having ends thereof connected to intake valves and supported on said intake-side rocker shaft such that said intake-side rocker arms rock, the intake-side rocker arms being driven by intake cams, the intake side rocker arms including, a first rocker arm having an end thereof connected to the intake valve and supported on said intake-side rocker shaft such that said first rocker arm rocks, the first rocker arm being driven by a first low-lift cam, and a second rocker arm having an end thereof connectable to said first rocker arm and supported on said intake-side rocker shaft, the second rocker arm being adapted to engage with the first rocker arm at an angle substantially perpendicular to a center longitudinal axis of the intake valve, such that said second rocker arm rocks, the second rocker arm being driven by a high-lift cam causing a larger valve lift than the first low-lift cam; exhaust-side rocker arms having ends thereof connected to exhaust valves and supported on said exhaust-side rocker shaft such that said exhaust-side rocker arms rock, the exhaust-side rocker arms being driven by an exhaust cam; and a switching mechanism switching operating characteristics of the intake valves, wherein the intake-side rocker shaft is provided with the switching mechanism and has a larger diameter than the exhaust-side rocker shaft.