A nozzle assembly of a fuel injector includes a nozzle body in which a needle member is adapted to translate. The nozzle assembly is further provided with an electrical circuit so that an electrical signal enabling contact detection is measurable between the needle member and the nozzle body. The nozzle assembly also includes a piezoresistive device which continuously varies the electrical signal during the final closing displacements, or the initial opening displacements, of the needle, the variations of the signal being a function of a differential pressure.

Various embodiments include a method for operating an internal combustion engine with a fuel injection system including a piezo actuator comprising: stopping the discharge phase of the actuator during an injection cycle; measuring a voltage profile at the actuator; comparing a feedback signal at the actuator with a setpoint value; varying the discharge time of the actuator in successive injection cycles until the feedback signal corresponds to the setpoint value; defining a servo valve closing time as a defined offset with respect to the optimized discharge time; and using the defined servo valve closing time to set an injection quantity of fuel for future injection cycles.

An injector has an injector needle (2) by means of which an outlet opening (4) of an injector housing (1) can be closed. The injector needle (2) can be adjusted in pressure-controlled fashion from a closed position into an open position. The injector needle (2) is axially fixedly connected to a piston (26) which is under closing pressure in one direction so that the injector needle (2) closes the outlet opening (4). In the other direction, the piston (26) and thus the injector needle (2) can be displaced by a valve-controlled control pressure, whereby the injector needle (2) passes into its open position and releases the outlet opening (4).

A fuel injection valve for fuel injection systems of internal combustion engines, in particular for directly injecting fuel into the combustion chamber of an internal combustion engine. The fuel injection valve includes a solenoid, an armature acted upon in a closing direction by a return spring through the solenoid, and a valve needle connected to the armature in force-locking fashion for actuating a valve closing body, which together with a valve seat surface forms a sealing seat. An adjustment element for adjusting the spring force of a return spring is arranged in a connecting sleeve serving the inlet side fuel supply. The adjustment element is bounded outwardly by a thin-walled sleeve. The sleeve includes an axially aligned sleeve jacket and a radially extending sleeve base. The wall thickness of the sleeve base is reinforced relative to the wall thickness of the sleeve jacket of the sleeve.

A nozzle assembly of a fuel injector includes a nozzle body in which a needle member is adapted to translate. The nozzle assembly is further provided with an electrical circuit so that an electrical signal enabling contact detection is measurable between the needle member and the nozzle body. The nozzle assembly also includes a piezoresistive device which continuously varies the electrical signal during the final closing displacements, or the initial opening displacements, of the needle, the variations of the signal being a function of a differential pressure.

A method of detecting failures of an engine control computer including at least: a hardware layer, a software layer comprising at least one activation cycle of the load m phase(s) of activation of said load with: actuation of the load, first timeout, deactivation of the load, second timeout. The method of detecting failures includes a measurement time window during which the following are carried out: an initialization of the measurement variables, detection of an actuation of the load, an action of reinitializing the engine control computer if at least one of the following conditions is valid: T1>T1_ref, T2<T2_ref, T3>T3_ref, T4<T4_ref.

A fuel injector for controlling delivery of gaseous fuel into an intake passage of an internal combustion engine defines a fuel flow passage extending in a direction of fuel flow from an inlet to an outlet. An actuator moves a normally closed valve member from a closed to an open position. An annular valve seat is inclined relative to a direction of fuel flow, causing gaseous fuel to flow against the direction of fuel flow and act on the valve member in an opening direction when said actuator is energized to move the valve member to the open position. The valve member includes an extension including helical ribs defining helical channels, the helical ribs bearing on an inside surface of an outflow passage to guide axial movement of the valve member and said helical channels imparting a centripetal acceleration to said gaseous fuel as it flows through the outflow passage.

Methods and systems for operating a direct fuel injector of an internal combustion engine are described. In one example, a nozzle needle is moved in two directions to maintain fuel flow through the direct fuel injector and to reduce the possibility of the nozzle needle impacting a piezoelectric actuator. The method and system may permit long fuel injection times without causing undesirable impacts between components of a fuel injector.

A fuel injection valve (6) is configured such that the effective opening area of an injection port (61) increases as its lift amount increases. A fuel injection control unit (an engine control unit 100) injects fuel in a lift amount changing mode wherein, when fuel is injected into a combustion chamber (17) in the terminal period of the compression stroke, the lift amount of the fuel injection valve is set to a predetermined large lift amount in the earlier period of the injection period, and in the later period of the injection period following the earlier period of the injection period, the lift amount is set to a small lift amount smaller than the large lift amount and is in a range where the fuel injection speed increases.

Various embodiments may include a method for operating a diesel-common-rail piezo-operated servo injector comprising: partially charging the piezo-actuator from a non-charged state at 0 V (method a); partially discharging the piezo-actuator from an already charged state to a remaining limited charge (method b); measuring the piezo-voltage with both methods and comparing the results; when the comparison demonstrates correspondence within a predefined threshold, using method b in ranges in which method a cannot be carried out; and when the comparison does not demonstrate correspondence within the predefined threshold, using method a without using method b.