Mazda Motor Corporation

Norihisa Murata

Tatsuya Koga

Jiro Kato

Haruna Yanagida

Shinji Sumi

Provided is an exhaust device connected to an engine body. The exhaust device includes a plurality of independent exhaust pipes, each of which has a circular cross section, and which are connected to exhaust ports of cylinders of the engine body; and a mixing pipe having a circular cross section, connected to downstream ends of the independent exhaust pipes, and through which exhaust gas that has passed through the independent exhaust pipes flows in. The independent exhaust pipes are connected to an upstream end of the mixing pipe in such a manner that parts of internal spaces of the circular cross sections overlap each other in a predetermined section from the downstream ends of the independent exhaust pipes toward upstream, and a ratio of overlapping portions of the circular cross sections gradually increases from upstream toward downstream.

Exhaust device of multiple-cylinder engine

An exhaust device of a multi-cylinder engine which controls local introduction of exhaust gas to a catalyst device and a variation between cylinders of introduction positions of the exhaust gas to the catalyst device is provided. The exhaust device is arranged so that the cylinders extend in a vehicle width direction at a vehicle front part, and an exhaust line is arranged so as to extend rearward from a rear of the engine, wherein, in sequence from an upstream side of an exhaust gas flow, four independent exhaust pipes corresponding to the cylinders, collecting pipes which collect all independent exhaust pipes, and the catalyst device are provided. The single exhaust pipe includes two bending parts and a downstream part thereof is connected so that the exhaust gas is introduced from a direction that is diagonally lateral to an inlet part of the catalyst device.

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Hiroshima, Japan

Norihisa Murata