초록 ▼

An evaporative fuel-processing system for an internal combustion engine has an evaporative emission control system and a pressure sensor. An ECU carries out negative pressurization of the interior of the evaporative emission control system, by opening a purge control valve and closing a vent shut va

An evaporative fuel-processing system for an internal combustion engine has an evaporative emission control system and a pressure sensor. An ECU carries out negative pressurization of the interior of the evaporative emission control system, by opening a purge control valve and closing a vent shut valve. The purge control valve is closed over a predetermined time period after the interior of the evaporative emission control system is brought into the predetermined negatively pressurized state, and a rate of decrease in negative pressure within the evaporative emission control system is detected. Then, it is determined whether or not there is leakage from the evaporative emission control system, based on the detected rate of decrease in the negative pressure, and at least one detected pressure value at at least one predetermined time point within the predetermined time period over which the purge control valve is closed.

대표청구항 ▼

An evaporative fuel-processing system for an internal combustion engine having an intake system, and a fuel tank, comprising: an evaporative emission control system including a canister having an adsorbent accommodated therein, for adsorbing evaporative fuel generated in said fuel tank, and an air i

An evaporative fuel-processing system for an internal combustion engine having an intake system, and a fuel tank, comprising: an evaporative emission control system including a canister having an adsorbent accommodated therein, for adsorbing evaporative fuel generated in said fuel tank, and an air inlet port communicating with atmosphere, a charging passage extending between said canister and said fuel tank, a purging passage extending between said canister and said intake system, a purge control valve arranged across said purging passage, and a vent shut valve for opening and closing said air inlet port of said canister; pressure-detecting means for detecting pressure within said evaporative emission control system; negatively pressurizing means for negatively pressurizing an interior of said evaporative emission control system into a predetermined negatively pressurized state, by opening said purge control valve and closing said vent shut valve; leakage-checking means for closing said purge control valve over a predetermined time period after said interior of said evaporative emission control system is brought into said predetermined negatively pressurized state by said negatively pressurizing means, and for detecting a rate of decrease in negative pressure within said evaporative emission control system by using first and second pressure values detected respectively at first and second predetermined time points within said predetermined time period; and leakage-determining means for determining whether or not there is leakage from said evaporative emission control system, based on said rate of decrease in said negative pressure within said evaporative emission control system detected by said leakage-checking means, and a third pressure value detected by said pressure-detecting means at a third predetermined time point exclusive of said first and second time point within said predetermined time period over which said purge control valve is closed.