Valve operating system in internal combustion engine

Claim 2

A valve operating system in an internal combustion engine, comprising first, second and third intake-side cams and first and second exhaust-side cams all provided on a single cam shaft for correspondence to a cylinder of the engine, first and second intake-side rocker arms operatively connected independently to a pair of intake valves for the cylinder and a third intake-side rocker arm disposed between the first and second intake-side rocker arms, which arms are swingably carried on an intake-side rocker shaft for engagement with said first, second and third intake-side cams, respectively, first and second exhaust-side rocker arms operatively connected independently to a pair of exhaust valves for the cylinder and swingably carried on an exhaust-side rocker shaft for engagement with said first and second exhaust-side cams, respectively, and a connection switchover mechanism provided on the intake-side rocker arms and capable of switching-over the connection and disconnection of the adjacent intake-side rocker arms, wherein said first to third intake-side cams are provided adjacent one another in an axial direction on said cam shaft, said first, second and third intake-side rocker arms are disposed between said first and second exhaust-side rocker arms, and at least two of said first, second and third intake-side rocker arms, as well as said first and second exhaust-side rocker arms, are in rolling contact with the corresponding cams through rollers, said first and second exhaust-side rocker arms being provided with notches for accommodating portions of said first and second intake-side rocker arms, respectively.

Claim 3

A valve operating system in an internal combustion engine according to claim 1, wherein said second intake-side cam corresponding to said second intake-side rocker arm has an outer surface substantially circular about an axis of the cam shaft, the second intake-side cam having a substantially narrow width in an axial direction, and said second intake-side rocker arm is provided with a notch for accommodating a portion of said second exhaust-side rocker arm and with a slipper having a small width to come into direct sliding contact with said second intake-side cam.

Claim 4

A valve operating system in an internal combustion engine according to claim 1, further including a lost motion mechanism provided in proximity to a center line between said pair of intake valves.

Claim 5

A valve operating system in an internal combustion engine according to claim 3, wherein said lost motion mechanism is associated with said third intake-side rocker arm, which is disposed in the middle.

Claim 6

A valve operating system in an internal combustion engine according to claim 1, further including a plug pipe for a spark plug, which plug pipe is disposed between said pair of exhaust valves and between said first and second exhaust-side rocker arms.

Claim 7

In a valve operating system for a multicylinder overhead cam type internal combustion engine having first, second and third intake-side cams and first and second exhaust-side cams all provided on a single cam shaft positioned above at least one cylinder, first and second intake-side rocker arms operatively connected independently to a pair of intake valves for the cylinder and a third intake-side rocker arm disposed between the first and second intake-side rocker arms, which arms are swingably carried on an intake-side rocker shaft for engagement with said first, second and third intake-side cams, respectively, first and second exhaust-side rocker arms operatively connected independently to a pair of exhaust valves for the cylinder and swingably carried on an exhaust-side rocker shaft for engagement with said first and second exhaust-side cams, respectively, a connection switchover mechanism provided on the intake-side rocker arms and capable of switching-over the connection and disconnection of the adjacent intake-side rocker arms, said first to third intake-side cams are provided adjacent one another in an axial direction on said cam shaft, said first, second and third intake-side rocker arms are disposed between said first and second exhaust-side rocker arms, and at least two of said first, second and third intake-side rocker arms, as well as said first and second exhaust-side rocker arms are provided with rollers for rolling contact with the corresponding cams, and improvement comprising, said first and second exhaust-side rocker arms being provided with axial notches reducing their width in the axial direction of the camshaft near the camshaft for accommodating portions of said first and second intake-side rocker arms, respectively, near the camshaft and reducing the overall width of the combined rocker arms in said axial direction.

Claim 8

In a valve operating system for a multicylinder overhead cam type internal combustion engine having first, second and third intake-side cams and first and second exhaust-side cams all provided on a single cam shaft positioned above at least one cylinder, first and second intake-side rocker arms operatively connected independently to a pair of intake valves for the cylinder and a third intake-side rocker arm disposed between the first and second intake-side rocker arms, which arms are swingably carried on an intake-side rocker shaft for engagement with said first, second and third intake-side cams, respectively, first and second exhaust-side rocker arms operatively connected independently to a pair of exhaust valves for the cylinder and swingably carried on an exhaust-side rocker shaft for engagement with said first and second exhaust-side cams, respectively, a connection switchover mechanism provided on the intake-side rocker arms and capable of switching-over the connection and disconnection of the adjacent intake-side rocker arms, said first to third intake-side cams are provided adjacent one another in an axial direction on said cam shaft, said first, second and third intake-side rocker arms are disposed between said first and second exhaust-side rocker arms, and at least two of said first, second and third intake-side rocker arms, as well as said first and second exhaust-side rocker arms are provided with rollers for rolling contact with the corresponding cams, and improvement comprising, said first and second exhaust-side rocker arms being provided with axial notches reducing their width in the axial direction of the camshaft near the camshaft for accommodating portions of said first and second intake-side rocker arms, respectively, near the camshaft and reducing the overall width of the combined rocker arms in said axial direction.

Claim 9

A valve operating system according to claim 6, wherein said second intake-side cam corresponding to said second intake-side rocker arm has an outer surface substantially circular about an axis of the cam shaft, the second intake-side cam having a substantially narrow width in an axial direction, and said second intake-side rocker arm is provided with an axial notch for accommodating an axial portion of said second exhaust-side rocker arm for further reducing the combined axial width of the rocker arms.

Claim 10

A valve operating system according to claim 7, wherein said second intake-side rocker arm is provided with a slipper for engaging said second intake-side cam, said slipper having a narrow width in the axial direction.

Claim 11

A valve operating system according to claim 6, further including a plug pipe for a spark plug, which plug pipe is disposed between said pair of exhaust valves and between said first and second exhaust-side rocker arms.