Mazda Motor Corporation

Mazda Corp.

Daijirou Ishimoto

Yasushi Nakahara

Yoshiyuki Uehane

Atsuhiro Hatabu

Hideya Horii

Kazuhiro Kosugi

Minori Fujino

Kazuhiro Okino

Masamichi Takahashi

A multi-cylinder engine includes an engine body having first and second cylinder groups, first and second exhaust passage groups each having a plurality of independent exhaust passage parts and a collective exhaust passage part, and an exhaust gas recirculation (EGR) passage. In a plan view in cylinder axis directions, the passage groups are disposed adjacent to each other, and, in the first exhaust passage group, a first independent exhaust part of the plurality of independent exhaust passage parts is connected to the EGR passage and a second independent exhaust passage part is connected to the collective exhaust passage part so as to be directed to a connection of the first independent exhaust passage part to the collective exhaust passage part, and in the second exhaust passage group, an opening of the collective exhaust passage part is offset toward the first exhaust passage group in a lineup direction.

Multi-cylinder engine

An intake-side space around intake ports and an exhaust-side lower space around exhaust ports are provided in a main cooling jacket portion. These spaces are connected to each other. In a sub cooling jacket portion, an exhaust-side upper space is provided at a level above the exhaust-side lower space. The main cooling jacket portion and the sub cooling jacket portion are connected to each other via a cylindrical-hole connecting passage extending vertically and separate from each other vertically via a wall portion in another area than the connecting passage. Accordingly, a cooling device of an engine which can restrain the exhaust gas from being cooled too much improperly is provided.

Cooling device of water-cooled engine and method of manufacturing the same

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Hatsukaichi, Japan

Daijirou Ishimoto