Method of detecting abnormality in an evaporative fuel-purging system for internal combustion engines

摘要

A method of detecting abnormality in an evaporative fuel-purging system (evaporative emission control system) for an internal combustion engine comprises the steps of: (1) determining whether or not the engine is in a predetermined operating condition after completion of warming-up of the engine, (2) temporarily inhibiting purging of evaporative fuel into an intake passage when it is determined that the engine is in the predetermined operating condition, (3) obtaining a first value based on a parameter reflecting an amount of evaporative fuel purged into the intake passage during the temporary inhibition of the purging of the evaporative fuel, (4) obtaining a second value based on the parameter during execution of the purging of the evaporative fuel carried out after the temporary inhibition of the purging of the evaporative fuel, (5) comparing the first value with the second value, and (6) determining whether or not there is abnormality in the evaporative fuel-purging system, based on a result of the comparison.