Gm Global Technolgoy Operations, Inc.

Paolo Zamboni

Maura Dintino

Roberto Vernassa

In a fuel injection system of an internal combustion engine, including, but not limited to a high pressure pump adapted to deliver a fuel mass conveyed from a fuel tank to a high pressure region to which a plurality of injectors is connected, including a fuel metering device for adjusting the fuel quantity to be delivered to the high pressure region, a pressure sensor for measuring fuel pressure in the high pressure region; and an electronic control unit arranged for driving the fuel metering device through an energizing signal (Inom; Iact) as a function of the measured fuel pressure and the engine operating mode, where the electronic control unit is arranged for determining the energizing signal (Inom; Iact) for driving the fuel metering device according to a nominal characteristic curve (A) of the high pressure pump representative of a predetermined relationship between the energizing signal and the fuel mass delivered by the pump, the operating pressure is controlled by driving the fuel metering device with an energizing signal determined according to an updated characteristic curve (B) estimated by applying to the nominal characteristic curve (A) an offset between the actual energizing signal value (Iact) related to the controlled fuel mass delivered to the high pressure region in a predetermined engine operating point and a nominal energizing signal (Inom) related to the controlled fuel mass according to the nominal characteristic curve (A).

Method and system for controlling a high pressure pump, particularly for a diesel engine fuel injection system

In a fuel injection system of an internal combustion engine that includes, but is not limited to injectors (I-I), each of which is adapted to deliver a predetermined amount of pressurized fuel to a combustion chamber of a respective cylinder (C-C) of the engine, a high-pressure accumulator volume common to the injectors (I-I) and arranged to maintain the fuel at high-pressure, a pressure sensor for measuring fuel pressure in the accumulator volume, a metering unit for adjusting the fuel pressure in the accumulator volume as a function of the measured pressure, so as to maintain a predetermined target injection pressure set-point dependent on the engine operating point by returning excess fuel to a fuel tank; and an electronic control unit arranged for controlling fuel injection timing and quantity by operating injectors control valves, the operating pressure is controlled by triggering retarded injections (INJpost) of a predetermined quantity of fuel to the combustion chamber of the cylinders (C-C) of the 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 the combustion process, thereby reducing pressure in the accumulator volume.

Growing community of inventors

Turin, Italy

Paolo Zamboni