Yamaha Hatsudoki Kabushiki Kaisha

Takeshi Iwanami

Minoru Yonezawa

Takamitsu Suzuki

Two embodiments of compact high performance induction systems for V type engines that include pairs of plenum chambers that extend over the respective cylinder banks. First pairs of runners extend from an inlet opening in each plenum chamber to an outlet opening that communicates with the cylinder of the opposite bank. Second pairs of intake passages are provided which extend from inlet openings in the respective plenum chambers to outlet openings in the cylinders of the adjacent cylinder head. The first intake passages have portions that extend through the other plenum chambers and the second intake passages communicate with the cylinders through these intermediate portions. The intermediate portions are curved and in one embodiment the second intake passages are tangential to these curved portions and in the other embodiment they are radial to it.

Engine induction system

An improved induction system for a V type engine that is tuned for substantially all running conditions and which is nevertheless compact in construction. The system includes a pair of plenum chambers each disposed adjacent one of the cylinder heads of the engine. Each cylinder head has at least two intake passages serving the respective cylinder bores and a first conduit extends from the adjacent plenum chamber to one of the intake passages and a second conduit extends from the other of the plenum chambers to the other intake passage. The plenum chambers communicate with each other at their opposite ends to improve air flow and a common inlet opening serves each plenum chamber inlet. A throttle valve arrangement is also incorporated so that good performance is achieved under all running conditions. The throttle valve arrangement includes a throttle valve that controls the flow through the interconnecting passage.

Intake passage for multi-cylinder engine

An improved induction system for a V type engine that is tuned for substantially all running conditions and which is nevertheless compact in construction. The system includes a pair of plenum chambers each disposed adjacent one of the cylinder heads of the engine. Each cylinder head has at least two intake passages serving the respective cylinder bores and a first conduit extends from the adjacent plenum chamber to one of the intake passages and a second conduit extends from the other of the plenum chambers to the other intake passage. The plenum chambers communicate with each other at their opposite ends to improve air flow and a common inlet opening serves each plenum chamber inlet. A throttle valve arrangement is also incorporated so that good performance is achieved under all running conditions.

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Hamakita, Japan

Takeshi Iwanami