| 摘要 |
PURPOSE:To increase the purifying ability of catalysts and to enhance the exhaust-gas purifying effect, by preheating combustion-assisting air by a preheater formed between a heat-insulating member and the outer wall of a reducing catalyst, and then supplying the preheated combustion-assisting air into an exhaust passage from a combustion- assisting air inlet port located just at the front of an oxidizing catalyst. CONSTITUTION:An engine 1 has a power unit 5 such as a generator and a carburetor 2 to which a fuel passage 3 and an air passage 4 are connected. Further, a reducing catalyst 6, an oxidizing catalyst 9, a silencer 7, a waste- heat recovering heat exchanger 10, etc. are provided in an exhaust passage of the engine 1. Combustion-assisting air is introduced from a combustion-assisting air inlet port 18 and passed through a preheater 17 formed between a heat-insulating member 16 and the outer walls of the reducing catalyst 6 and the silencer 7. Then, the combustion-assisting air is supplied to the oxidizing catalyst 9 by drawing it from a combustion-air inlet 8 by th ejector effect of exhaust-gas flow and used as combustible matter burning air on the oxydizing catalyst 9. With such an arrangement, it is enabled to device the ability of the catalysts 6, 9 effectively and to thereby enhance the exhaust-gas purifying effect. |
