| 摘要 |
PURPOSE:To prevent output, drivability and fuel consumption from being worsened, by making an increase of advance angle of the ignition timing as a quantity of EGR increases, with said increase raising a speed of combustion. CONSTITUTION:For the throttle valve when fully closed and slightly opened, an EGR valve 7, vacuum advance angle device 16, control valves 29, 36 are not operated with an operation of EGR not made, and an angle advancement of the ignition timing is also not operated. By an increase of the load, with the throttle valve made opening to above a prescribed degree of opening, a negative pressure, applied to a negative pressure chamber 10, goes lower with a quantity of EGR controlled to a small amount. On the other hand, though a degree of angle advancement is small, a less quantity of EGR makes a degree of advancement angle most suitable for the condition. When becoming a time of speed acceleration or high load operation, an exhaust pressure goes higher with both of the control valves 29, 36 operated together. A negative pressure, working on the negative pressure chamber 10, goes higher with a big quantity of EGR operated. And with a negative pressure fed to a negative pressure chamber 18, an ignition angle is largely advanced. |
