초록 ▼

An abnormality detecting apparatus for use in a fuel-transpiration preventing mechanism can eliminate effects of changes in operating conditions and variations in equipment to increase the accuracy of abnormality detection. Fuel gas generated in a fuel tank and then absorbed by an absorbing material

An abnormality detecting apparatus for use in a fuel-transpiration preventing mechanism can eliminate effects of changes in operating conditions and variations in equipment to increase the accuracy of abnormality detection. Fuel gas generated in a fuel tank and then absorbed by an absorbing material accommodated in a canister is discharged to an intake pipe by opening and closing a purge control valve. A change in pressure at a negative-pressure holding time after introduction of a negative pressure to the fuel-transpiration preventing mechanism and a change in pressure at an atmosphere-air introduction time after the negative-pressure holding time are calculated and the changes in pressure are used as a basis for determining the existence of an abnormality. As a result, effects of changes in operating conditions and effects of variations in purge control valves and canister closing valves can be eliminated, thus allowing the detection accuracy to be improved.

대표청구항 ▼

[ What is claimed is:] [1.] An abnormality detecting apparatus for use in a fuel-transpiration preventing system, said apparatus comprising:fuel-transpiration preventing means for absorbing fuel gas generated in a fuel tank using an absorbing material in a canister installed on a purge passage conne

[ What is claimed is:] [1.] An abnormality detecting apparatus for use in a fuel-transpiration preventing system, said apparatus comprising:fuel-transpiration preventing means for absorbing fuel gas generated in a fuel tank using an absorbing material in a canister installed on a purge passage connecting said fuel tank and an intake pipe of an internal combustion engine and, by opening and closing a purge control valve in accordance with an operating state of said internal combustion engine, introducing said absorbed fuel gas into said intake pipe to thereby prevent transpiration of said fuel gas;pressure detecting means for detecting a pressure in said fuel-transpiration preventing means;atmosphere-exposure-hole closing means for closing an atmosphere-exposure hole bored through a wall of said canister;first pressure-change computing means for computing a change in pressure detected by said pressure detecting means at a negative-pressure holding time after introduction of a negative pressure to said fuel-transpiration preventing means from said intake pipe according to predetermined control criteria to open and close said purge control valve and said atmosphere-exposure-hole closing means;second pressure-change computing means for computing a change in pressure detected by said pressure detecting means at an atmosphere-air introduction time for introducing air from the atmosphere by way of said atmosphere-exposure-hole closing means following said negative-pressure holding time for holding a negative-pressure in said fuel-transpiration preventing means according to predetermined control criteria to open and close said purge control valve and said atmosphere-exposure-hole closing means; andabnormality detecting means for detecting an abnormality in said fuel-transpiration preventing means based on said changes in pressure calculated by said first and second pressure-change computing means.