Yamaha Hatsudoki Kabushiki Kaisha

Osamu Tamura

Kimitake Otome

Shunichi Kometani

A number of embodiments of multi cylinder engines having direct cylinder injection wherein the fuel injector is positioned so as to be shrouded by the piston during at least a portion of its stroke. This permits the use of less expensive and lower pressure fuel injection nozzles. The spray pattern of the injector is chosen so that some fuel is sprayed toward the spark plug to provide stratification, but the major portion is directed toward the head of the piston so to as insure a homogeneous mixture when operating at high speed, high load conditions. All of fuel injectors are on the same side of the cylinder block and served by the same fuel rail.

Engine injection system for multi-cylinder engine

A number of embodiments of two-cycle engines employing Schnurle-type scavenging. In addition, a tumble port is also incorporated so as to introduce a tumble charge into the combustion chamber and reduce the likelihood of fresh charge from exiting from the exhaust port. This tumble charge may be utilized to achieve stratification, and the fuel charge may be delivered to the combustion chamber through the tumble port or in proximity to it. Also, arrangements are shown for controlling the amount of tumble flow.

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Iwata, Japan

Osamu Tamura