Abstract: A method is provided for estimating a hydraulic dwell time between a first injection pulse and a second injection pulse performed by a fuel injector of an internal combustion engine. The method includes, but is not limited to determining a value of an electric dwell time between the first injection pulse and the second injection pulse, estimating a value of an injector closing delay between an instant in which an electric closing command of the first injection pulse is generated and an instant in which the fuel injector closes, estimating a value of an injector opening delay between an instant in which an electric opening command of the second injection pulse is generated and an instant in which the fuel injector opens, and calculating a value of the hydraulic dwell time as a function of the electric dwell time value, of the injector closing delay value and of the injector opening delay value.

Abstract: Methods, a fuel supply system, and a computer readable medium embodying a computer program product are provided for controlling rail pressure in a fuel supply system comprising a fuel pump, an injector and a rail connecting the injector to the pump. At least one of the methods includes, but is not limited to establishing a relationship between said rail pressure and a leak rate of the injector, estimating a fuel drain rate from said rail based on a fuel injection rate, the rail pressure and said rail pressure/leak rate relationship, estimating a desired intake flow rate of said pump based on said fuel drain rate, and controlling the pump to operate at said desired intake flow rate.

Abstract: A method is provided for estimating a hydraulic dwell time between a first injection pulse and a second injection pulse performed by a fuel injector of an internal combustion engine. The method includes, but is not limited to determining a value of an electric dwell time between the first injection pulse and the second injection pulse, estimating a value of an injector closing delay between an instant in which an electric closing command of the first injection pulse is generated and an instant in which the fuel injector closes, estimating a value of an injector opening delay between an instant in which an electric opening command of the second injection pulse is generated and an instant in which the fuel injector opens, and calculating a value of the hydraulic dwell time as a function of the electric dwell time value, of the injector closing delay value and of the injector opening delay value.

Abstract: A method is provided for estimating fuel injecting pressure of an injector belonging to a fuel injection system of an internal combustion engine. The fuel injection system includes, but is not limited to a fuel rail and at least one injector that are fluidly connected with the fuel rail through a connecting conduit. The method includes, but is not limited to modelling the pressure fluctuation within the connecting conduit according to the equation P=B·e?At cos(?t), where A, B and ? are parameters, and t is a variable representing time, determining the dwell time between the injector opening and injector previous closing, and applying the determined dwell time to the equation in order to calculate the fuel injecting pressure.

Abstract: A fuel delivery injection system that includes, but is not limited to a fuel tank connected to a high pressure fuel pump. The fuel is pumped from the pump and distributed to direct acting piezoelectric injectors by means of a distribution hydraulic circuit. An electronic control unit controls the pump, the injectors and receives the pressure indications from a control valve associated to said distribution circuit. The distribution circuit includes, but is not limited to a small distribution rail having a volume of about 4-6 cm3 and the pipes connecting the rail to the injectors having a dimension of about 3 mm or slightly higher.

Abstract: Methods, a fuel supply system, and a computer readable medium embodying a computer program product are provided for controlling rail pressure in a fuel supply system comprising a fuel pump, an injector and a rail connecting the injector to the pump. At least one of the methods includes, but is not limited to establishing a relationship between said rail pressure and a leak rate of the injector, estimating a fuel drain rate from said rail based on a fuel injection rate, the rail pressure and said rail pressure/leak rate relationship, estimating a desired intake flow rate of said pump based on said fuel drain rate, and controlling the pump to operate at said desired intake flow rate.