Patent ID: 7891342

Claim:
A method for controlling operating pressure in a fuel injection system of an internal combustion engine, comprising the steps of: supplying fuel under a predetermined target high pressure to an accumulator volume common to a plurality of electrically controlled fuel injectors (I 1 -I 4 ), each of which is adapted to deliver a predetermined amount of pressurized fuel to a combustion chamber of a respective one of a plurality of cylinders (C 1 -C 4 ) of the internal combustion engine; measuring fuel pressure in an accumulator volume; and adjusting the fuel pressure in the accumulator volume as a function of the fuel pressure, so as to maintain a predetermined target injection pressure set-point dependent on an internal combustion engine operating point by returning excess fuel to a fuel tank; controlling injection timing by triggering retarded injections (INJpost) of a predetermined quantity of fuel to the combustion chamber of the plurality of cylinders (C 1 -C 4 ) of the internal combustion engine during a respective exhaust stroke, when pressure above a predetermined threshold (THover) is detected in the accumulator volume, so as to discharge fuel from the accumulator volume without it taking part to a combustion process, thereby reducing pressure in the accumulator volume.