APPARATUS AND METHOD FOR NON-INTRUSIVE TESTING OF MOTOR VEHICLE EVAPORATIVE FUEL SYSTEMS

摘要

An apparatus and method for the non-intrusivetesting of evaporative fuel vapor systems of motor vehicles.A portable pressure control and monitoring unit is insertedinto the fuel filler neck of a vehicle. The vapor ventline, leading from the fuel tank to the charcoal canisterof the evaporative system, is temporarily clamped off.Pressurized gas is introduced into the unit from anoperator's console, expanding a ring bladder and sealing anannular volume between the unit and the filler neck. Gas isthen passed through the unit into the contained volume ofthe evaporative system. After the neck cap is replaced, anautomatic timer deflates the ring bladder, charging theremaining volume of the evaporative system. Pressure decaydata is collected and stored in the unit's digital storagedevice Initially, this data is used in a pass/faildetermination made by a microprocessor in the unit. Later,the data is downloaded into a separate computer for archivalpurposes.