Yanmar Co., Ltd.

Masataka Sugimoto

Jiro Fukudome

[Problems] Provided is a configuration in which a member is not interposed between exhaust gas and a partition wall of an engine coolant passage, and the exhaust gas is caused to directly collide with the partition wall of the engine coolant passage, thus raising the gas flow velocity in a heat exchange part, which enables further improving the exhaust heat recovery rate. [Means for Solving Problems] An engine exhaust gas heat recovery device () recovers heat from engine exhaust gas by performing heat exchange between the engine exhaust gas and engine coolant. A plurality of spray holes () facing an inner cylinder tube () of a coolant passage () have been provided in an outer tube () of an exhaust gas inflow tube (), and the exhaust gas is caused to directly collide with the inner cylinder tube () of the coolant passage (). A minimum distance from each of the spray holes () to the inner cylinder tube () of the coolant passage () is in a range of 1.5 to 7 times the diameter of the spray holes. A relationship between a total opening area of the spray holes () and an exhaust gas flow rate is (total spray hole area/exhaust gas mass flow rate)=2.0 to 4.5 (cm/(kg/min)).

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Amagasaki, Japan

Masataka Sugimoto