MALFUNCTION DIAGNOSING DEVICE FOR VAPORIZED FUEL TREATMENT EQUIPMENT

摘要

PURPOSE: To provide a malfunction diagnosing device for vaporized fuel treatment equipment improving the performance of the malfunction diagnosis, improving the chance of the malfunction diagnosis without malfunction. CONSTITUTION: The malfunction diagnosing device for vaporized fuel treatment equipment has a first malfunction diagnosing means 13 for diagnosing the malfunction of a large hole observing the pressure decreasing degree in a fuel tank in the state introducing an engine intake negative pressure with isolating a purge passage 4 of the vaporized fuel connecting the fuel tank 1 and the engine intake passage 6 from the outside air, a second diagnosing means for the malfunction diagnosis corresponding to a small hole with observing the pressure increasing degree in the closed state isolating the outside air after decreasing the inside of the fuel tank to the predetermined negative pressure, and a working region B of the second diagnosis means is enlarged to the lower negative pressure side than the working region of the first diagnosis means including the working region A of the first diagnosis means.