Patent ID: 6148803
Filing Date: 2000-11-21
Classification: F02M

Abstract:
A leakage diagnosing apparatus for an evaporated gas purge system having a fuel tank, an intake pipe for an engine, a passage which connects the fuel tank to the intake pipe, a canister installed in the passage for adsorbed evaporated gas, a purge control valve installed in the passage for controlling a purge of said adsorbed evaporated gas from the canister to the intake pipe, comprising:leakage diagnosing means for diagnosing purge system leakage based on a detected pressure chance amount and an introduced pressure which is introduced into a part of the purge system including at least the fuel tank and the canister, said detected pressure change amount being obtained by detecting pressure in said part of the purge system after said part of the purge system is hermetically sealed, wherein said leakage diagnosing means further includes:compensation means for compensating said detected pressure change amount based on said introduced pressure; andcomparison means for comparing said detected pressure change amount with a determination value.