Methods for operating an internal combustion engine

Abstract

Methods for operating and limiting leaks in an internal combustion engine (ICE) powered by gaseous fuel, the ICE comprising a fuel delivery system for delivering via a supply line 15 gaseous fuel to a fuel rail 16 through a pressure regulator 14, the source of gaseous fuel including at least one gas tank 12 with which is associated a tank isolation valve 20; a supply line section between the isolation valve 20 and the pressure regulator 14 is referred to as high-pressure section (A); in a first aspect the method comprises monitoring for the occurrence of a gas leak and if detected limiting the leakage by operating the engine in a predetermined operating mode selected based on the location and / or magnitude of the leak; in a second aspect a refuelling line 24 branches from the high-pressure section (A) and comprises a filling receptacle for interfacing with a refuelling station and a check valve 34 at or near the connection with the high-pressure section; after tank refuelling a purge procedure is performed wherein injection events are performed while the isolation valve 20 is closed, until pressure in the high-pressure section has decreased to a predetermined threshold. Fig. 1