Means for variable valve timing for engine
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorTakeshi Oyaizu
Life of this patent
Estimating the term…
Abstract
Several embodiments of variable valve timing arrangements for double overhead camshaft engines having cylinder banks disposed at an angle to each other. In each embodiment, the variable timing is achieved by means of a pair of idler sprockets that are disposed between the camshafts of the respective cylinder banks and which are operated in unison so as to rotate the camshafts in an appropriate direction to achieve simultaneous valve timing adjustment of all camshafts in the desired relationship. In addition, an improved arrangement is disclosed for driving the camshafts of one cylinder bank from those of another cylinder bank.
Claims18
A variable timing camshaft drive for an internal combustion engine having a first cylinder bank, a first camshaft rotating about a first axis for operating at least one valve associated with said first cylinder bank, a second cylinder bank disposed at an angle to said first cylinder bank, a second camshaft rotating about a second axis for operating at least one valve associated with said second cylinder bank, a drive sprocket driven by said engine and rotatable about a third axis, a single flexible transmitter trained about said first and said second camshafts and said drive sprocket for driving said first and said second camshafts in unison with each other, and means for simultaneously rotating said first and said second camshafts in the same direction relative to said drive sprocket for simultaneously changing the events of the valves operated by said camshafts in the same sense.
A camshaft drive system for an internal combustion engine comprising a first cylinder bank, a first cylinder head affixed to said first cylinder bank and defining at least a first combustion chamber, first and second camshafts journaled for rotation relative to said first cylinder head about parallel first and second axes, a second cylinder bank disposed at an angle to said first cylinder bank, a second cylinder head affixed to said second cylinder bank and defining at least a second combustion chamber, third and fourth camshafts journaled for rotation relative to said second cylinder head about parallel third and fourth axes, a drive sprocket driven by said engine, and a flexible transmitter trained around said drive sprocket and said first, second, third and fourth camshafts for driving all of said camshafts in unison with said drive sprocket, the portion of said flexible transmitter extending between said second and said third camshafts comprising a single straight flight not engaged with an idler sprocket.
Dependencies are inferred from the claim text.