Yamaha Hatsudoki Kabushiki Kaisha

Tetsushi Saito

Naoki Tsuchida

Hiroyuki Tsuzuku

Tatsuo Niiyama

Kazuo Shimada

A number of embodiments of twin overhead cam shaft reciprocating machines having a plurality of poppet valves. A variable valve timing mechanism is interposed between the cam shafts and respective of the poppet valves for varying their lift and for changing the number of effective poppet valves per cylinder. The lift changing mechanism includes means for shifting at least one rocker arm follower and provides a relatively compact yet highly efficient structure for achieving this purpose.

Multi valve engine with variable valve operation

A cooling and lubricating system for an internal combustion engine wherein an oil cooler and oil filter are mounted at a lower portion of the cylinder block in a recess formed by the crankcase member to provide a compact assembly and wherein the oil filter is readily accessible. All of the passages for supplying lubricant and coolant to and from the oil cooler and oil filter are formed integrally in the body of the engine so as to avoid the use of external conduits.

Lubricating arrangement for engine

Variable valve timing mechanism

A number of embodiments of multiple-valve internal combustion engines having at least some of the valves being deactivatable by means of a hydraulic tappet assembly so as to control the flow path and flow pattern into and out of the combustion chamber. A hydraulic system is provided for controlling which of the valves operate and, if desired, the lift of the valves.

Valve actuating structure for multi-valve engine

A number of embodiments of overhead cam internal combustion engines having multiple intake and exhaust valves. The valve actuating mechanism is such that the valves are opened at a non-symmetrical rate so as to minimize the clearance requirements at top dead center and also so as to minimize the overlap between the closing of the exhaust valve and the opening of the intake valve without decreasing volumetric efficiency. A number of embodiments having either direct or rocker arm actuation are disclosed.

Valve operating system for multi-valve engine

A number of embodiments of engine construction having chain-driven overhead camshafts closed by a timing case cover and which timing case cover forms at least in part a coolant pump to the engine. Various arrangement for circulating the liquid coolant through the engine and an oil cooler mounted at the base of the engine are disclosed.

Engine cooling system

An improved camshaft and accessory drive arrangement for a V type engine wherein pairs of overhead cams are driven from the crankshaft by means of intermediate shafts that are directly driven by the crankshaft. The axis of rotation of the intermediate shafts is disposed closer to the axis of rotation of the crankshaft than the axes of rotation of the camshafts. An accessory is positioned in the valley of the V and is also driven by the crankshaft but is spaced further from the crankshaft axis of rotation than the intermediate shafts. This accessory is a water pump and an oil pump is also driven by the crankshaft at the same end of the engine.

Camshaft and accessory drive arrangement for engine

A lubrication arrangement for an engine and more particularly to an arrangement for lubricating the valve train of an engine. The valve train includes a cylinder head that journals an intake and an exhaust camshaft through bearings formed in the cylinder head and the cam cover. Hydraulic lash adjusters are associated with each of the camshafts and there are more intake adjusters than exhaust adjusters. An arrangement is provided for delivering lubricant to the lash adjusters and the camshaft journals which includes a passageway formed in the cam cover. Lubricant is delivered to the cylinder head in proximity to the intake adjusters so that the intake adjusters and the exhaust adjusters will receive lubricant at substantially the same pressure.

Lubrication arrangement for engine

A valve arrangement for a cylinder head assembly employing three intake valves and two exhaust valves for each cylinder. Not all of the intake valves reciprocate along parallel axes and hydraulic adjusters are operatively associated with the camshafts and rocker arms that operate the valves from the respective camshafts. The geometric relationship of the valves is chosen so as to maintain a compact and effective combustion chamber configuration and facilitate machining of the bores in which the hydraulic adjusters are positioned.

Growing community of inventors

Iwata, Japan

Tetsushi Saito