Yamaha Hatsudoki Kabushiki Kaisha

Sadayuki Shinmura

Akira Yamada

Takumori Yoshida

Several embodiments of induction systems for internal combustion engines that achieve high power outputs without sacrificing low and medium speed running characteristics or without adverse transitional effects. Each embodiment employs a pair of intake valves connecting with each combustion chamber and served by separate intake passages. A control valve is positioned at one of the intake passages and is operated so that the idle and low load requirements are primarily served by the other intake passage. An interconnecting passage interconnects the two intake passages downstream of the control valve and close to the engine valves to improve transitional performance and mid-range torque. In one embodiment of the invention the control valve is operated in response to engine speed and load as sensed in the induction system. In another embodiment an unbalanced control valve is employed that is operated by pressure differences in the induction system. In yet another embodiment the control valve is operated in response to the exhaust gas pressure. In still another embodiment a piston type control valve is employed.

Growing community of inventors

Iwata, Japan

Sadayuki Shinmura