Patent ID: 7753035

Claim:
A method for diagnosing the operation of a purge device ( 28 ) comprising a purge valve ( 31 ) for purging a fuel vapor canister ( 29 ) of a vehicle internal combustion engine ( 1 ), said purge valve ( 31 ) communicating, via a vapor recirculation pipeline, with an air inlet manifold ( 5 ) of the engine ( 1 ) in order to recirculate at least some of these vapors thereto when the valve ( 31 ) is open, the method comprising the steps of: a) determining a value of at least one one of i) an inlet pressure and ii) an inlet mass flow rate in the air inlet manifold ( 5 ), the inlet mass flow rate being measured at a region upstream of an opening of a vapor recirculation pipeline ( 21 ) into the air inlet manifold, b) issuing a command to open the purge valve ( 31 ), c) providing engine control electronics of the engine ( 1 ) with the value determined in step a), the value being provided to the engine control electronics without taking account of a mass flow rate passing through said purge valve ( 31 ) and whether said purge valve ( 31 ) is open or closed, d) allowing one of i) an actual mass flow rate and ii) an actual pressure of the air actually admitted to the engine ( 1 ) through said inlet manifold ( 5 ) to generate a variation in the operation of the engine inconsistent with the value determined during step a), e) detecting at least one engine operating parameter to determination an occurrence of the variation in the operation of the engine during step d), and using the determination of the variation to determine at least one of i) a deficiency in opening of the purge valve ( 31 ) and ii) a malfunctioning of the purge device ( 28 ) and f) upon determining the one of the deficiency and the malfunctioning in step e), respectively adjusting the operation of the purge valve and the purge device.