| 摘要 |
PURPOSE:To inform the operator of a trouble of a VSV(vacuum switching valve) instantly and the like when the VSV generates an opening trouble. CONSTITUTION:An EGR passage 82 for exhaust gas recirculation, an EGR valve 8 to open and close, a negative pressure passage 89 to lead in the suction negative pressure to the EGR valve 84 as an operation pressure, a VSV 90 or the like driven and controlled to open and close the negative pressure passage 89, a VCV(vacuum control valve) 96 to cut off the leading of the operation pressure to the EGR valve 84 when a throttle valve 4 is fully closed as a fail- safe in an opening trouble of the VSV 90, and the like are provided. In a light load area other than the idling condition, the actual suction pressure in a surge tank 2, and the logic suction pressure detected by the throttle opening and the engine rotation frequency are read to an ECU 71, and compared and decided, and when the actual suction pressure is larger than the logic suction pressure, it is decided to be an opening trouble of the VSV 90 so as to light an opening trouble lamp 102, and the operator and the like are informed of the trouble. |
