| 摘要 |
PURPOSE:To purify exhaust gas easily at the time of low load and prevent engine components from being overheated at the time of high load by providing a fitting plate protrusively along the whole peripheral surface of a catalyst-filled base cylinder, then fixing the tip part of the fitting plate airtightly to the inner wall surface of an exhaust passage, and setting the wall thickness of the fitting plate to be smaller than the width of the base cylinder. CONSTITUTION:A fitting plate 72 is protrusively provided along the whole peripheral surface of a catalyst-filled base cylinder 71 of a catalyst unit 7, and the fitting plate 72 is held by a cylinder body 52 and an inner cover 61 to fix the catalyst unit 7 airtightly to an exhaust passage 524. The wall thickness of the fitting plate 72 is made smaller than the width of the base cylinder 71, and an insulating space A is formed between the exhaust passage 524 and the base cylinder 71. The heat-of-reaction of a catalyst is not thereby transmitted easily to engine components, so that exhaust gas can be purified easily at the time of low load, and the engine components are prevented from being overheated at the time of high load. |
