EVAPORATED FUEL CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

PURPOSE:To avoid rich condition of an air fuel ratio so as to ensure desired operation performance by controlling an evaporated fuel control device so as to reduce a purge flow when a allowable purge flow is small, in the case where purge of fuel steam to an intake system, is under stopping condition, or its purge operation is started again. CONSTITUTION:A canistor 20 is connected to an intake pipe 2 through a purge pipe 17 in which a first purge control valve 18 and a negative pressure valve 19 are interposed and it is connected to a fuel tank 16 through a communicating pipe 34 in which a two way valve 33 is interposed. The purge pipe 17 is connected to the negative pressure chamber 22 of the negative pressure valve 19 through a negative pressure communicating passage 27 and a second purge control valve 28. Respective purge control valves 18 and 28 are driven and controlled on the basis of output signals from various kinds of sensors by an ECU 5. In this case, a purge flow which flows in the purge pipe 17 is added at the time of purge of fuel steam so as to find out a purge flow integrated value, and also the integrated value is subtracted when purge operation is stopped. When the purge flow integrated value is a prescribed bottom value or less, the purge flow is reduced.