| 摘要 |
PURPOSE:To prevent rapid increase in the concentration of NOx in the exhaust gas at the acceleration by delaying increase in the vacuum advance under the EGR at the acceleration. CONSTITUTION:When a thermosensitive valve 15 is communicated between ports 18 and 21 above a given engine temperature, a diaphragm chamber 11 of an EGR valve is connected to a vacuum port 23b and according to the opening or colsing of a throttle valve 22, EGR is performed. When the throttle valve 22 is opened for acceleration, vacuum developing in the vacuum port 23a is immediately fed to a vacuum delay valve 41 through a vacuum action valve 24 and a check valve 36. But it is fed to a diaphragm chamber 35 of an ignition timing vacuum advance device 34 with a time lag due to the delay effect of the vacuum delay valve. Accordingly, the increase in the ignition timing due to a distributor 33 can be delayed at the acceleration thereby reducing the NOx concentration in the exhaust at the time. |
