| 摘要 |
PROBLEM TO BE SOLVED: To solve problems that a secondary air feeding means in exhaust gas is required when an oxidation catalyst is used, the exhaust emission purification ratio is degraded when the exhaust temperature exceeds a predetermined value, and a cost is high if a three-way catalyst is used. SOLUTION: In a gas engine with a catalyst 2 for purifying exhaust emission disposed in an exhaust passage 1, only the oxidation catalyst is used for the catalyst 2, and the excess air ratio of fuel/air mixture is set to be larger than 1.0 and smaller than 1.5. Much air is contained in the exhaust emission, and any secondary air feeding means is not required though the oxidation catalyst is used. Further, no three-way catalyst is used, and the catalyst itself is less costly, the excess air ratio of the fuel/air mixture need not be adjusted correctly. In addition, any expensive oxygen sensor or high-accuracy controller need not be used, and the cost is reduced. COPYRIGHT: (C)2004,JPO
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