Yamaha Hatsudoki Kabushiki Kaisha

Hironao Takahashi

Masaaki Yoshikawa

Shigenobu Uchiyama

Masaki Yoshikawa

A compact small displacement automotive internal combustion engine that has its cylinder bores inclined to the vertical and that has a reentrant configured induction system that provides long intake runners while maintaining an engine that has its longitudinal width in the engine compartment substantially equal to its vertical height. In addition the engine has an improved accessory mounting arrangement.

Four-stroke engine

A variable valve timing mechanism for an internal combustion engine wherein the camshaft is supported at one end by a combined bearing and valve body member that is detachably connected to the supporting engine body. The connection is such that fluid from the engine lubricating system can be delivered to this body and distributed by a control valve mounted in it. This simplifies machining of the engine body and permits a more compact, lower cost construction without sacrificing any function. The control valve is mounted in a bore that is accessible through the side of the cylinder head and is actuated by a servo motor mounted on the exterior of the cylinder head to provide a compact, rigid and easily serviced assembly.

Cylinder head for variable valve timing

Two embodiments of overhead camshaft internal combustion engines wherein the camshafts are provided with cutouts in the area adjacent the cam lobes so as to keep the center of gravity in the lobed area closer to the rotational axis of the camshaft and also to improve balance and reduce vibration.

Cam shaft for engine

A twin overhead camshaft internal combustion engine embodying a variable valve timing mechanism on each of the camshafts. The variable valve timing mechanism is operated hydraulically by lubricant that is supplied to it through a bearing surface of the camshaft so as to minimize external conduits and connections and to simplify sealing.

Variable valve timing arrangement for engine

An internal combustion engine having a variable valve timing mechanism with a hydraulic control that is mounted on the front of the cylinder head for ease of accessibility and for ease of conversion of the existing engine. The engine includes an oil filter, oil cooler, and coolant pump, which are disposed and driven in a way so as to maintain short flow paths and permit internal conduits to be formed in the engine so as to avoid the possibility of leakage. The variable valve timing mechanism is controlled by hydraulic pressure supplied by the lubricating system, and a control valve assembly is mounted on the cover for the variable valve timing mechanism with the control passages being formed integrally in this cover. In addition, one of the timing chains may be easily accessed for adjustment without removing the cover through the removal of a bolt that holds an accessory mounting bracket to the engine.

Growing community of inventors

Iwata, Japan

Hironao Takahashi