In a fuel system of an internal combustion engine, fuel is delivered by a high-pressure pump into a fuel rail. The quantity of the delivered fuel is influenced by a quantity control valve (30) actuated by an electromagnetic actuating device. A limit-value retaining current is ascertained, at which the quantity control valve still remains in its closed state or is just opening.

In a fuel system of an internal combustion engine, fuel is delivered by a high-pressure pump into a fuel rail. The quantity of the delivered fuel is influenced by a quantity control valve (30) actuated by an electromagnetic actuating device. A limit-value retaining current is ascertained, at which the quantity control valve still remains in its closed state or is just opening.

Disclosed is a method for monitoring a fuel injector, the injector including a piezoelectric actuator controlling a valve unit to open or close the injector, the fuel injector including an actuator play. The method includes: measuring a plurality of compensation times of the actuator play during a simulation step preceding an injection for a given plurality of fuel pressures; calculating a parameter representing the current actuator play per the measured compensation times; comparing the parameter representing the calculated current actuator play with a predetermined reference parameter of the actuator play; and transmitting a warning message if the reference parameter is exceeded; the parameter representative of the current actuator play being calculated on the basis of a polynomial function of the measured compensation times. The polynomial order of the polynomial function corresponding to the number of measured compensation times of the actuator play for different fuel pressures.

Disclosed is a method for monitoring a fuel injector, the injector including a piezoelectric actuator controlling a valve unit to open or close the injector, the fuel injector including an actuator play. The method includes: measuring a plurality of compensation times of the actuator play during a simulation step preceding an injection for a given plurality of fuel pressures; calculating a parameter representing the current actuator play per the measured compensation times; comparing the parameter representing the calculated current actuator play with a predetermined reference parameter of the actuator play; and transmitting a warning message if the reference parameter is exceeded; the parameter representative of the current actuator play being calculated on the basis of a polynomial function of the measured compensation times. The polynomial order of the polynomial function corresponding to the number of measured compensation times of the actuator play for different fuel pressures.

Innovative, high-pressure fuel systems and related methods are provided. Such systems and methods enable engines to use fuel more effectively.

Innovative, high-pressure fuel systems and related methods are provided. Such systems and methods enable engines to use fuel more effectively.