| 摘要 |
PURPOSE:To provide smooth control of a carbureter and quick rerise of a speed to an expected value once a vehicle is accelerated during deceleration by placing the forward and backward motion of a main nozzle into and from a barrel under negative pressure control by use of the feature that a negative prssure in an intake manifold during deceleration is higher than an idling negative pressure and by gradually varying an air fuel ratio during deceleration by use of the feature of a delay of transmission of the negative pressure. CONSTITUTION:When a vehicle is shifted from intermediate or high speed run S to deceleration run D, a throttle valve 4 is suddenly closed and a negative pressure V in an intake manifold is thereby quickly increased from a ''L'' to a ''H''. A delay port 40 lets the quickly increased negative pressure gradually transmitted into a negative pressure chamber 37. When the negative pressure gets lower than an idling negative pressure, a resiliently pushing spring 36 forces a diaphragm 34 to push a main jet 21 so that an air fuel ratio A/F is gradually leaned to a ''L'', as shown by a curvd line l2, and then, the fuel is finally cut at a point which is delayed by C' from an ordinary fuel cutting point C. At this time, the vehicle is shifted from S to D, namely, an engine r.p.m. N is reduced from the ''H'' to the ''L''. In short, after a needle 18 is shifted in association with the closing motion of the valve 4, the main jet 21 is gradually pushed forward, whereby discharged fuel is reduced and finally cut. |
