METHOD FOR DETERMINING THE INJECTION CORRECTION WHEN CHECKING THE TIGHTNESS OF A TANK VENTILATION SYSTEM

摘要

The invention relates to a method for determining an additive corrective value used for correcting the fuel injection quantity of an internal combustion engine, said method being carried out while checking the tightness of a tank ventilation system. In the tank ventilation system, a tank ventilating valve (14) is disposed in a regeneration pipe (4) which connects a storage container (5) collecting fuel gas (9) of a fuel tank (7) to an intake pipe (2) of the internal combustion engine. The tank ventilation system is airtightly sealed towards the atmosphere (11) prevailing outside the motor vehicle while the tank ventilating valve (14) is opened to create a negative pressure in the tank ventilation system. The inventive method comprises the following steps: the fuel gas charge (L) of the storage container (5) is determined; the volume flow rate (V) through the tank ventilating valve (14) is determined; an intermediate value (Z) is calculated from the product of the load (L) and the volume flow rate (V); a tank pressure difference (p) between the pressure prevailing in the fuel tank (7) and the atmospheric pressure (11) is determined; and the additive corrective value (K) is determined by adjusting the intermediate value (Z) to the amount of the tank pressure difference (p).