Patent ID: 6336446
Filing Date: 2002-01-08
Classification: F02M

Abstract:
An evaporated fuel treatment apparatus for an internal combustion engine comprising:an evaporated fuel discharge prevention system including a fuel tank, a canister having an opening to the atmosphere, a passage allowing the fuel tank to communicate with the canister, and a purging passage allowing the canister to communicate with the intake manifold of the engine; a pressure sensor for detecting the pressure of the evaporated fuel discharge prevention system; and a controller coupled to the pressure sensor for judging the presence of a first leak in the evaporated fuel discharge prevention system if a change in the pressure from the pressure sensor is small, said controller checking a change in the pressure from said pressure sensor when said system is closed after placing said system under a negative pressure; wherein said controller judges the presence of a large leak if the first leak is judged and the pressure increases instantaneously upon closing said system.