S.O.H.C. five valve engine
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorMakoto Shimamoto
Life of this patent
Estimating the term…
Abstract
A number of embodiments of single overhead camshaft five valve per cylinder internal combustion engines. The camshaft and valve operating mechanism is designed so as to permit a compact assembly by placing the camshaft outwardly of the area between the valves. Both direct and rocker arm valve actuation embodiments are disclosed although in the direct valve operating arrangement, rocker arms are employed for operating some of the valves. The valve and bearing arrangement for the camshaft permits the cam lobes to be positioned closely adjacent each other to maintain compactness of the engine design. In all embodiments, a central spark plug position is accommodated and the spark plug extends generally parallel to the axis of the associated cylinder bore.
Claims41
A cylinder head assembly for a five valve, single overhead camshaft engine comprising a cylinder head defining at least in part a combustion chamber, a first set of three valves supported for reciprocation along respective axes by said cylinder head on one side of a first plane passing through said combustion chamber, a second set of two valves supported for reciprocation along respective axes by said cylinder head on the other side of said first plane, a camshaft journaled for rotation relative to said cylinder head about an axis parallel to said first plane and offset from said first plane on said one side a greater distance than all of the valves of said first set, means for actuating said first set of valves from said camshaft comprising at least a first cam lobe positioned substantially on a second plane passing perpendicular to said first plane and passing through the center of said combustion chamber, a pair of cam lobes positioned on opposite sides of said first cam lobe, a pair of rocker arms each engaging a respective one of said pair of cam lobes and a respective one of said second set of valves for operating said second set of valves from said camshaft, and a spark plug mounted in said cylinder head between said pair of rocker arms.
A single overhead camshaft arrangement for a multiple valve internal combustion engine comprising a cylinder head adapted to be affixed to a cylinder block to close one end of a cylinder bore formed therein, a camshaft supported for rotation relative to said cylinder head by a pair of bearings spaced apart a distance substantially equal to the diameter of said cylinder bore, at least four cam lobes formed on said camshaft between said spaced bearings for operating a plurality of valves supported in said cylinder head for reciprocation and serving said cylinder bore, said plurality of valves comprising five valves consisting of a first set of three valves supported for reciprocation along respective axes by said cylinder head on one side of a first plane passing through the axis or the cylinder bore, a second set of two valves supported for reciprocating along respective axes by said cylinder head on the other side of said first plane, means for directly actuating said first set of valves from said camshaft comprising a first set of three cam lobes each directly actuating a respective valve of said first set, one cam lobe of said first set being positioned substantially on a second plane passing perpendicular to said first plane and passing through the axis of said cylinder bore and a first pair of cam lobes positioned adjacent said bearings, a second pair of cam lobes positioned on opposite sides of said first cam lobe and between said first pair of cam lobes, a pair of rocker arms each engaging a respective one of said second pair of cam lobes and a respective one of said second set of valves for operating said second set of valves from said camshaft, said pair of rocker arms being pivotally supported on a single rocker arm shaft lying on the other side of said first plane.
A single overhead camshaft arrangement for a multiple valve internal combustion engine comprising a cylinder head adapted to be affixed to a cylinder block to close one end of a cylinder bore formed therein, a camshaft supported for rotation relative to said cylinder head by a pair of bearings spaced apart a distance substantially equal to the diameter of said cylinder bore, at least five cam lobes formed on said camshaft between said spaced bearings for operating a plurality of valves supported in said cylinder head for reciprocation and serving said cylinder bore, said plurality of valves comprising five valves consisting of a first set of three valves supported for reciprocation along respective axes by said cylinder head on one side of a first plane passing through said combustion chamber, a second set of two valves supported for reciprocation along respective axes by said cylinder head on the other side of said fist plane, lobes, means for actuating said first set of valves from said camshaft comprising at least a first cam lobe positioned substantially on a second plane passing perpendicular to said first plane and passing through the center of said combustion chamber and a first pair of cam lobes positioned adjacent said bearings, a first set of three rocker arms journaled on a common rocker arm shaft and each engaged with one of said first cam lobe and said first pair of cam lobes and a respective valve of said first set, a second pair of cam lobes positioned on opposite sides of said first cam lobe and between said first pair of cam lobes, a pair of rocker arms each engaging a respective one of said second pair of cam lobes and a respective one of said second set of valves for operating said second set of valves from said camshaft, said common rocker arm shaft being disposed outwardly of the cylinder bore axis and below the tips of said second set of valves.
A cylinder head arrangement for an overhead camshaft internal combustion engine, said cylinder head forming in part a combustion chamber, at least three poppet valves for serving said combustion chamber, a tappet associated with one of said valves for operating said valve, a camshaft journaled for rotation relative to said cylinder head, said camshaft having a first lobe cooperating with said tappet for operating said one valve, a second and a third lobe formed on said camshaft on opposite sides of said first lobe and spaced apart a distance less than the diameter of said tappet, said second and third lobes having a smaller effective diameter than said first lobe, and means for operating a second poppet valve from said second cam lobe and a third poppet valve from said third cam lobe.
A cylinder head assembly for a five valve, single overhead camshaft engine comprising a cylinder head defining at least in part a combustion chamber, a first set of three valves supported for reciprocation along respective axes by said cylinder head on one side of a first plane passing through said combustion chamber, a second set of two valves supported for reciprocation along respective axes by said cylinder head on the other side of said first plane, a camshaft journaled for rotation relative to said cylinder head about an axis parallel to said first plane and on one side thereof, means for actuating said first set of valves from said camshaft comprising at least a first cam lobe positioned substantially on a second plane passing perpendicular to said first plane and passing through the center of said combustion chamber, a pair of cam lobes positioned on opposite sides of said first cam lobe, a pair of rocker arms journaled on a common rocker arm shaft and each engaging a respective one of said pair of cam lobes and a respective one of said second set of valves for operating said second set of valves from said camshaft, and a spark plug mounted in said cylinder head between said pair of rocker arms, said rocker arm shaft passing adjacent an area where said spark plug is positioned and being provided with a recessed area to clear the spark plug.
A cylinder head assembly for a five valve, single overhead camshaft engine comprising a cylinder head defining at least in part a combustion chamber, a first set of three valves supported for reciprocation along respective axes by said cylinder head on one side of a first plane passing through said combustion chamber, a second set of two valves supported for reciprocation along respective axes by said cylinder head on the other side of said first plane, a camshaft journaled for rotation relative to said cylinder head about an axis parallel to said first plane and on one side thereof, means for actuating said first set of valves from said camshaft comprising a first set of three cam lobes, the center of which is positioned substantially on a second plane passing perpendicular to said first plane and passing through the center of said combustion chamber, a pair of cam lobes positioned on opposite sides of said center cam lobe, a pair of rocker arms pivotally supported on a single rocker arm shaft and each engaging a respective one of said pair of cam lobes and a respective one of said second set of valves for operating said second set of valves from said camshaft, the pivotal supports of said pair of rocker arms on said single rocker arm shaft being aligned with the second and third cam lobes of said first set of cam lobes and a spark plug mounted in said cylinder head between said pair of rocker arms.
A cylinder head assembly for a five valve, single overhead camshaft engine comprising a cylinder head defining at least in part a combustion chamber, a first set of three valves supported for reciprocation along respective axes by said cylinder head on one side of a first plane passing through said combustion chamber, a second set of two valves supported for reciprocation along respective axes by said cylinder head on the other side of said first plane, a camshaft journaled for rotation relative to said cylinder head about an axis parallel to said first plane and on one side thereof, means for actuating said first set of valves from said camshaft comprising at least a first cam lobe positioned substantially on a second plane passing perpendicular to said first plane and passing through the center of said combustion chamber and directly actuating at least one of said first set of valves, said one valve having a keeper retainer assembly for engagement with a valve spring, a pair of cam lobes positioned on opposite sides of said first cam lobe in overlapping relation to said keeper retainer assembly of said one valve of said first set, a pair of rocker arms each engaging a respective one of said pair of cam lobes and having a respective one of said second set of valves for operating said second set of valves from said camshaft, said pair of cam lobes a smaller diameter than said first cam lobe, the means for journaling said camshaft on said cylinder head comprising a pair of bearing surfaces formed on said camshaft outwardly of said pair of cam lobes with no bearing surfaces being formed between said pair of cam lobes, and a spark plug mounted in said cylinder head between said pair of rocker arms.
A cylinder head assembly for a five valve, single overhead camshaft engine comprising a cylinder head defining at least in part a combustion chamber, a first set of three valves supported for reciprocation along respective axes by said cylinder head on one side of a first plane passing through said combustion chamber, a second set of two valves supported for reciprocation along respective axes by said cylinder head on the other side of said first plane, a camshaft journaled for rotation relative to said cylinder head about an axis parallel to said first plane and on one side thereof, means for directly actuating said first set of valves from said camshaft comprising at least a first cam lobe positioned substantially on a second plane passing perpendicular to said first plane and passing through the center of said combustion chamber and second and third cam lobes, each directly operating a valve of said first set, a pair of cam lobes positioned on opposite sides of said first cam lobe, a pair of rocker arms each engaging a respective one of said pair of cam lobes and a respective one of said second set of valves for operating said second set of valves from said camshaft, and a spark plug mounted in said cylinder head between said pair of rocker arms.
A cylinder head assembly for a five valve, single overhead camshaft engine comprising a cylinder head defining at least in part a combustion chamber, a first set of three valves supported for reciprocation along respective axes by said cylinder head on one side of a first plane passing through said combustion chamber, a second set of two valves supported for reciprocation along respective axes by said cylinder head on the other side of said first plane, a camshaft journaled for rotation relative to said cylinder head about an axis parallel to said first plane and on one side thereof, means for actuating said first set of valves from said camshaft comprising at least a first cam lobe positioned substantially on a second plane passing perpendicular to said first plane and passing through the center of said combustion chamber and second and third cam lobes each operating a respective rocker arm, all of said rocker arms operating, said first set of valves being pivotally supported on a common rocker arm shaft, a pair of cam lobes positioned on opposite sides of said first cam lobe, a pair of rocker arms each engaging a respective one of said pair of cam lobes and a respective one of said second set of valves for operating said second set of valves from said camshaft, and a spark plug mounted in said cylinder head between said pair of rocker arms.
Dependencies are inferred from the claim text.