| 摘要 |
PURPOSE:To improve the vaporizing characteristic in a device adapted to flow back part of the air drawn in each cylinder of an engine into an air inlet passage during its compression stroke by an arrangement wherein the location and the opening degree of the port of an air intake and return flow passage facing the air inlet passage are improved. CONSTITUTION:In a 3-port type engine, one end of an air intake and return flow passage 6 opens into a cylinder 2 and the other and thereof opens through an annular space 6a into the part of an air inlet passage 4 downstream of a carburettor 4. The opening 6b of the passage 6 is defined in the form of a slit in the direction perpendicular to the direction of flow of air drawn in through the air inlet passage 4. In brief, the opening 6b is formed so as to widen the opening degree thereof in the direction perpendicular to the direction of air flow through the air inlet passage 4 than the latter direction. The air intake and return flow passage 6 is provided with a control valve 15 which constitutes an air intake and return flow control valve together with an air intake and return flow valve 12. Thus, improved separation of fuel from the inner wall of the air inlet passage 4 can be obtained when air is drawn in and also when air flows back so that an improved vaporizing characteristic may be obtained. |
