| 摘要 |
PURPOSE:To aim at improvement of responsiveness and prevention of a backfire by communicating an air intake passage on the upstream course of a fuel injection valve to the middle part of a supplementary air passage. CONSTITUTION:One end 6a of a supplementary air passage 6 is connected to a space 5 in front of a fuel injection valve 2 while the other end 6b is connected to the upstream course of a throttle valve 11 inside an air intake passage 1. The supplementary air passage 6 has a branch passage 12, one end 12 of which is connected to the middle part of the supplementary air passage 6 and the other end 12b of which is connected to the air intake passage 1 on the upstream course of a fuel injection valve 2. A solenoid valve 13 used as a control valve is disposed in the proper middle part of the branch passage 12. The solenoid valve 13 is controlled by a control circuit 14 according to the opening of the throttle valve 11 or the negative pressure in the air intake passage 1, particularlly, opened during a transient operation wherein a negative pressure in the vicinity to the fuel injection valve 2 in the air intake passage 1 is weakened. Hence, a negative pressure will not remain inside the supplementary air passage and a backfire caused by response delay of fuel supply attributed to the remaining thereof may be avoided. |
