| 摘要 |
PURPOSE:To restrain the sudden increase of the amount of exhaust gas recirculation of the operating cylinders side by a method wherein a reverse flow preventing valve is closed, a fresh air supply valve is opened next and a fresh air interrupting valve is opened lastly with a time delay after fuel for resting side cylinders is interrupted when the all-cylinders operation is switched to the partial-cylinders operation. CONSTITUTION:A solenoid valve 15 is excited to close the reverse flow preventing valve 14 when a predetermined time is elapsed after stopping the operations of fuel injection valves a, b, c of the resting side cylinders #1-#3 and the beginning of counting of a clock pulse in a counter by a cylinder switching signal. Another solenoid valve 11 is excited to open the fresh air supply valve 12 immediately before the total closing of the reverse flow preventing valve 14 while a signal for switching the width of fuel injection pulse for the operating side cylinders #4-#6 is outputted further at the time when the fresh air supply valve 12 is opened totally. Lastly, still another solenoid valve 6 is excited to close the fresh air interrupting valve 4 and the same valve 4 is closed at about 200-500 mili-second after the output of the cylinder number switching signal. Accordingly, it may be avoided that the exhaust gas path of the operating cylinders side is filled with the gas immediately after the switching and causing misfire. |
