Method for the direct injection of fuel into an internal combustion engine

Method for the direct injection of fuel into an internal combustion engine, in which a high-pressure pump with a variable flow rate supplies the fuel to a common rail, which in turn supplies the fuel to a series of injectors, each of which performs its injection phase within an angular injection interval;

• the high-pressure pump comprising a number of cylinders, each of which is provided with a piston, an intake valve and a delivery valve;
• the method comprising:
• that each cylinder of the high-pressure pump is supplied with a substantially constant quantity of fuel during each intake phase,
• that the flow rate of the high-pressure pump is regulated by choking the pump stroke of each cylinder of the high-pressure pump so as to supply to the common rail a variable fraction of the fuel present in said cylinder at the end of the intake phase, and
• that a choking action of a pump stroke is performed for each injection phase of an injector;
• wherein the mechanical actuation of the high-pressure pump is timed so that each injection interval is located at the beginning of a respective choking action and that each pump stroke is choked by at least an angular interval having a duration no shorter than that of the injection intervals irrespective of the quantity of fuel to be supplied to the common rail in such a way that the injection phase of each injector always takes place when the high-pressure pump is not pumping fuel to the common rail.