초록 ▼

The invention is directed to a method for checking the tightness of a tank-venting system used with an internal combustion engine having an intake pipe. The tank-venting system includes a fuel tank wherein fuel vapor forms, a storage device connected to the fuel tank, the storage device having a ven

The invention is directed to a method for checking the tightness of a tank-venting system used with an internal combustion engine having an intake pipe. The tank-venting system includes a fuel tank wherein fuel vapor forms, a storage device connected to the fuel tank, the storage device having a vent opening and a device for closing the vent opening, and a tank-venting valve interconnecting the intake pipe and the storage device whereby the fuel vapor is conducted from the tank to the intake pipe via the storage device and the tank-venting valve. The method includes the steps of: (a) during operation of the engine and while the venting opening is closed, carrying out one of the following: (a1) opening the tank-venting valve and drawing a predetermined quantity of gaseous substance through the tank-venting valve, or (a2) opening the tank-venting valve and drawing a gaseous substance through the tank-venting valve so long until a predetermined underpressure is reached in the tank-venting system, so that a pressure fluctuation is produced in the tank-venting system with the pressure fluctuation being characterized by a plurality of characteristic variables; (b) evaluating at least one of the characteristic variables to judge the tightness of the tank-venting system.

대표청구항 ▼

A method for checking the tightness of a tank-venting system used with an internal combustion engine having an intake pipe, the tank-venting system including a fuel tank wherein fuel vapor forms, a storage device connected to the fuel tank, the storage device having a vent opening and a device for c

A method for checking the tightness of a tank-venting system used with an internal combustion engine having an intake pipe, the tank-venting system including a fuel tank wherein fuel vapor forms, a storage device connected to the fuel tank, the storage device having a vent opening and a device for closing the vent opening, and a tank-venting valve interconnecting the intake pipe and said storage device whereby said fuel vapor is conducted from said tank to said intake pipe via said storage device and said tank-venting valve, the method comprising the steps of: (a) during operation of the engine and while said venting opening is closed, carrying out one of the following: (a1) opening said tank-venting valve and drawing a predetermined quantity of gaseous substance through said tank-venting valve, or (a2) opening said tank-venting valve and drawing a gaseous substance through said tank-venting valve so long until a predetermined underpressure is reached in said tank-venting system, so that a pressure fluctuation is produced in said tank-venting system with said pressure fluctuation being characterized by a plurality of characteristic variables; (b) evaluating at least one of said characteristic variables to judge the tightness of said tank-venting system; closing said tank-venting valve after carrying out each set of said steps (a) and (b) until the pressure reduction caused by said opening thereof is again compensated; determining the mean closure time of said tank-venting valve over several periods of pressure compensation; forming a criterion for the tightness of said tank-venting system from said mean closure time as a characteristic variable of said pressure fluctuation; repeating said steps (a) and (b) after each elapse of a predetermined time span thereby averaging said characteristic variable; and, evaluating said characteristic variable to judge the tightness of said tank-venting system.