| 摘要 |
PURPOSE:To smoothen connecting performance between a primary air inlet path and a secondary air inlet path as well as raise the restarting property of an engine by providing a startup time valve opening means for the secondary throttle valve of a curbureter, a secondary valve opening means oprating in comply to negative pressure, and a startup time operating means for an accelerating pump. CONSTITUTION:When an ignition switch 72 is turned to ON by cranking operation, a negative pressure switch valve 58 is switched, the negaive pressue of the primary air inlet path 4 is transmitted to a first actuator 50, a secondary throttle valve 18 is opened by a given amount, an enriched mixed gas after the hard running is changed into a lean-mixed gas, and thereby the restarting property of the engine are improved. Also, since the fuel vapor of the secondary slow path 14 is discharged, the connecting performance can be also improved. On the other hand, the negative pressure is also transmitted to the second actuator 78, and the rod 16 of an acceleration pump 24 is pushed in for preparation of comformable response. Then, when a cranking signal turns OFF, the switch valve 58 is switched to the atmospheric presure side, but since the first actuator 50 operates through a delay valve 65, the air-fuel ratio during the restartup period is turned to a leaned one. During the cold startup period of the engine, high idling operation is kept to attain early stabilization. |
