Mazda Motor Corporation

Hironobu Hashimoto

Shinji Seike

Takashige Ishikawa

An induction system for use in a V-shaped engine having a forward bank and a rearward bank each provided with a row of cylinders, the induction system includes intake runners individually extending from the cylinders of each bank, the intake runners being convergedly connected at upstream end portions respectively. To upstream ends of thus converged connection portions are connected common intake passages, which are connected to a junction portion at a further upstream side, whereby the respective common intake passages are connected. The lengths of the intake runners from the cylinders up to a center of the converged connection portion are set equal to one another. The respective converged connection portions are arranged vertically above the rearward bank. A communicating passage is provided for communicating the center portions of the respective converged connection portions with each other. In the communicating passage is provided a valve for opening or closing the communicating passage according to an engine speed. In this induction system, the dynamic effects of induction can be efficiently utilized in a wide range of engine speed in a relatively simplified construction. In addition, an intake manifold can be arranged in such a manner as to make the size of the engine smaller.

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Kure, Japan

Hironobu Hashimoto