Abnormal diagnostic manner of the evaporation fuel purge device and the fuel vapor which is generated

摘要

PROBLEM TO BE SOLVED: To shorten time of interruption in a purge appreciably.;SOLUTION: A second-order difference integration value ΣΔΔP is computed from variations ΔP in internal pressure P detected in a purging state, and if the second-order difference integration value ΣΔΔP exceeds a first criterion value α1, a determination concludes that an oil level fluctuation of fuel based on a running state of a vehicle is in a state causing an anomalous rise in the internal pressure P. Upon a determination finding no anomalous rise in the internal pressure P, the purge is interrupted. If the second-order difference value ΣΔΔP computed from the internal pressure P detected in this state exceeds a second criterion value α2 set smaller than the first criterion value α1, a detection concludes that the fuel has an anomalous oil level fluctuation, and if a variation ΔP1 per determination time T1 for the internal pressure P exceeds a criterion value β, a detection concludes that a rise in fuel temperature based on the vehicle state is in a state causing an anomalous rise in the internal pressure P.;COPYRIGHT: (C)2002,JPO