| 摘要 |
PURPOSE:To eliminate sudden fluctuation of engine torque at on-off switching time and an uncomfortable shock feeling of a driver by providing constitution such that an exhaust gas recirculating(EGR) flow amount is gradually changed at transfer time from on to off and from off to on of EGR when an EGR trouble is diagnozed. CONSTITUTION:In a trouble diagnostic device for an exhaust gas recirculation(EGR) control device, exhaust gas, divided to flow in a recirculation pipe 5 connected to an exhaust pipe 15, is allowed to partly flow in an intake pipe 3 via a recirculating valve 11 and recirculated to an engine 1. Here, the recirculating valve 11 is a vacuum servo type valve set up in the recirculating pipe 5 connected between the exhaust pipe 15 and the intake pipe 3. A recirculating valve controlling solenoid 12 for controlling a passage area of the recirculating valve 11 is connected between a diaphragm chamber of the recirculating valve 11 and a negative pressure introducing port of the intake pipe 3 to control a negative pressure to the diaphragm chamber of the recirculating valve 11 by a drive signal from an electronic control unit 22. The recirculating valve controlling solenoid 12 closes the recirculating valve 11 at the time of no-excitation. |
