| 摘要 |
PURPOSE:To improve the mixing of suction air and exhaust gas and enable to miniaturize a primary suction air passage by a method wherein a part of the exhaust gas is re-circulated to the primary and secondary suction air passages, in an engine equipped with the primary suction air passage for a light load and the secondary suction air passage for a heavy load. CONSTITUTION:In the internal-combustion engine, of which carburetter is consisting of a primary carburetter 2 for the light load and a secondary carburetter 4 for the heavy load, exhaust gas reflux ports 33, 34 are opened near the choke valves 6, 8 of the suction air passages 10, 12 for respective carburetters 2, 4 and both reflux ports 33, 34 are communicated with and connected to an introducing port 22 opened in an exhaust passage 20 through EGR passages 31, 32, a three-way passage 26 and a reflux passage 24. The three-way passage 26 is provided with EGR control valves 28, 30 concerned to respective passages 31, 32 and respective valves 28, 30 are operated so as to be opened by a negative pressure introduced from sensing ports 40, 42 near the choke valves 6, 8 for respective suction air passages 10, 12. According to this constitution, a load to supply the reflux gas in the primary suction air passage 10 may be lightened and miniaturizing of the latter may be made possible. |
