A method according to the invention for checking the plausibility of the function of a pressure sensor in an injection system of an internal combustion engine includes acquiring a calibrated actuation profile, by which peak current values for opening at least one electrically actuatable injection valve are assigned to existing internal pressures. An existing internal pressure is measured in the form of an actual sensor pressure value by the pressure sensor. The method includes obtaining the electrical peak current value corresponding to the measured sensor pressure value from a calibrated actuation profile, such that the corresponding electrical peak current value acquired in this way is applied to the injection valve. Subsequently, an opening state of the injection valve is monitored in reaction to the applied electrical peak current value, and a functional state of the pressure sensor is assigned as a function of the opening state of the injection valve.

A method for operating a fuel injection system with pressure reduction, and a fuel injection system that includes a fuel injection valve with a servo valve are provided. The method for operating a fuel injection system includes performing a desired pressure reduction in the pressure accumulator using at least one fuel injection valve of the fuel injection system. This is achieved by opening a servo valve in the fuel injection valve, which is opened, during a pressure reduction phase, just wide enough that the actual closing element remains closed and as a result no fuel injection process takes place.

A fuel injector for use in an internal combustion engine includes a valve member that is moveable within a bore of an injection nozzle so as to be engageable with a valve seat region to control fuel delivery through one or more nozzle outlets, an injector body housing an actuator that is operable to move the valve member within the bore, and defining an accumulator volume for storing high pressure fuel. The fuel injector includes a damping chamber in fluid communication with the accumulator volume through a fluid passage, the damping chamber serving to reduce pressure wave activity within the accumulator volume.

Methods and systems are provided for an injector arrangement for an internal combustion engine. In one example, an injector arrangement may include an actuator positioned between a fuel injector and a cylinder head, with the actuator configured to adjust a position of the fuel injector relative to the cylinder head in order to adjust a protrusion amount of a fuel nozzle tip within a combustion chamber.

A method for determining the opening for piezo servo-driven injectors may include measuring a voltage and a charge at an end of a charging process of the piezo actuator; determining a provisional scaling factor by calculating Q/U; determining the maximum of C.sub.VORL and using the instant at which the maximum occurs as an approximation value of the valve opening instant; measuring the charge and voltage at the approximation of the valve opening instant; solving the equation:
1.25F.sup.2/EC=(UCQ).sup.2 Where F=force acting on the piezo actuator, E=electrical parameter of the piezo actuator; determining a new scaling factor from the solution of the equation; calculating the difference (UCQ) and determining a maximum of said value; and using the instant at which said maximum occurs as valve opening instant.

A fuel injection valve includes a body including a first chamber that supplies fuel of a first pressure, a second chamber that supplies fuel of a second pressure, and an injection hole, a valve chamber member including a valve chamber connectable to the first chamber and the second chamber, a control chamber member including a control chamber connectable to the first chamber, a needle pressed by pressure of fuel in the control chamber in a direction that causes fuel injection from the injection hole to stop, an actuator, a valve element that selectively connects the first chamber, second chamber, and the valve chamber according to the actuator extending and contracting, and a transmission mechanism that when the actuator extends, transmits the force to the needle as a force in a direction that causes fuel to be injected from the injection hole.

A high-pressure-side valve portion makes contact with and moves from a high-pressure seat surface formed in a body to control communication between a control chamber communication passage and a high-pressure passage. A low-pressure-side valve portion makes contact with and moves from a low-pressure seat surface formed in the body to control communication between an exhaust passage and a second intermediate chamber. A releasing portion in the high-pressure-side valve portion communicates with the control chamber communication passage when the high-pressure seat surface is in contact with the high-pressure-side valve portion to block the control chamber communication passage from the high-pressure passage. A valve element internal passage is formed in the valve element to communicate the releasing portion with the second intermediate chamber.

A valve cylinder partitions a first intermediate chamber from a second intermediate chamber. A first valve element in the first intermediate chamber includes a tubular high-pressure-side valve portion to control communication between a control chamber communication passage and the first intermediate chamber. A second valve element in the second intermediate chamber includes a low-pressure-side valve portion to control communication between an exhaust passage and the second intermediate chamber. A columnar rod portion located between the first valve element and the second valve element is slidably held at a cylinder hole of the valve cylinder. An internal passage communicates the control chamber communication passage with the second intermediate chamber. The high-pressure-side valve portion has an outer diameter greater than an outer diameter of the rod portion.

A fuel injector for use in an internal combustion engine includes a valve member that is moveable within a bore of an injection nozzle so as to be engageable with a valve seat region to control fuel delivery through one or more nozzle outlets, an injector body housing an actuator that is operable to move the valve member within the bore, and defining an accumulator volume for storing high pressure fuel. The fuel injector includes a damping chamber in fluid communication with the accumulator volume through a fluid passage, the damping chamber serving to reduce pressure wave activity within the accumulator volume.

Methods and systems are provided for an injector arrangement for an internal combustion engine. In one example, an injector arrangement may include an actuator positioned between a fuel injector and a cylinder head, with the actuator configured to adjust a position of the fuel injector relative to the cylinder head in order to adjust a protrusion amount of a fuel nozzle tip within a combustion chamber.