Mazda Motor Corporation

Takashi Kariya

Takayuki Tominaga

Ken Yoshida

Hiroshi Kinoshita

Shinji Fujihira

Fusatoshi Tanaka

Tatsuya Takahata

Takuya Yamada

Yuki Koda

Yuji Kojima

Tomonori Nishida

Noriaki Fujita

Shintaro Umesaki

Hiroyuki Ohmura

Naoya Matsumoto

Yusaku Matsumura

Takuya Nishihara

Arashi Imura

An exhaust gas recirculation system for a multi-cylinder engine is provided, which includes an exhaust manifold connected to a cylinder head, a catalyst connected to a downstream end of the exhaust manifold in terms of an exhaust gas flow, an EGR gas outlet provided downstream of the catalyst, an in-head EGR passage penetrating the cylinder head, and an EGR pipe extending from the EGR gas outlet and directly connected to an inlet of the in-head EGR passage to lead EGR gas thereto. The catalyst is disposed so that the exhaust gas flows therein from a first side to a second side in an engine cylinder lined-up direction. The EGR gas outlet is located on the second side with respect to the center of the engine in the cylinder lined-up direction, and the inlet of the in-head EGR passage is located in the first side with respect to the engine center.

Engine exhaust gas recirculation system

An engine EGR system is provided, which includes an engine body, an intake passage, an exhaust passage and an EGR passage configured to recirculate exhaust gas as EGR gas to the intake passage. The EGR passage includes an EGR cooler and an EGR internal passage constituting the EGR passage upstream of the EGR cooler, and including a passage passing through a cylinder head. The EGR internal passage has a bent pipe part including a first bent portion at which an upstream portion of the EGR internal passage is bent away from a gas inflow port of the EGR cooler, a second bent portion located downstream of the first bent portion and bending the EGR internal passage toward the gas inflow port, and an intermediate portion connecting the first and the second bent portions by being disposed therebetween. The water-cooling passage is disposed around the bent pipe part.

EGR system of engine

An engine EGR system is provided. An EGR passage includes an EGR cooler, an EGR internal passage passing through a cylinder head on an upstream side of the EGR cooler, and a relay passage extending outside the cylinder head and connecting the EGR internal passage to the EGR cooler. The EGR cooler formed in a columnar shape is arranged above an intake manifold so as to locate a gas inflow port on a first end surface side and a gas outflow port on a second end surface side, and the relay passage communicates with the EGR internal passage on an external side of the engine compared to a head EGR gas exit. The EGR cooler inclines downward from the gas outflow port toward the gas inflow port, and the relay passage is connected to the gas inflow port while being bent downward toward the upstream side.

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Aki-gun, Japan

Takashi Kariya