Exhaust emission control device for outboard motor

摘要

The present invention provides an improved exhaust emission control arrangement for an outboard motor. A catalyst material holding structure is mounted within an exhaust passage of an engine. A thermally insulating interstice is located between an inner wall of the exhaust passage and the outer periphery of the catalyst material holding structure, so that the interstice physically separates the catalyst material holding structure from the inner wall of the exhaust passage. The interstice prevents significant heat transfer between the catalyst material reaction sites at which exhaust gas cleansing takes place and engine components which are positioned proximate thereto. The invention permits the effective cleansing of exhaust gases under all engine operating conditions.