A high pressure hydraulic system comprising: a hydraulic chamber containing pressurized fluid, a wall which encloses at least one part of the hydraulic chamber and has an integral diaphragm, a piezoelectric sensor isolated from the pressurized fluid contained in the hydraulic chamber by the diaphragm, and an elastic element arranged to apply an elastic force to the piezoelectric sensor, between the piezoelectric sensor and the diaphragm, so that a deformation of the diaphragm produced by a change in the pressure of the fluid contained in the hydraulic chamber causes a change in the elastic force that the elastic element applies to the piezoelectric sensor.

A method for detecting the malfunction of a software solution configured to generate data representing the instant of interruption of fuel injection of an internal combustion engine. The method comprises acquiring data by a data acquisition device which is connected to a measurement device fixed to an injector body and configured to emit data representing closure instants of an injection nozzle, recording the data generated by the software solution and the data emitted by the measurement device, over a predetermined duration, synchronizing the data generated by the software solution and the data emitted by the measurement device, and comparing the data generated by the software solution and the data emitted by the measurement device, the software solution being considered to be malfunctioning when they do not satisfy predefined criteria.

Diagnostic systems and methods for a fuel system of an engine of a vehicle utilize a fuel rail pressure sensor, an engine speed sensor, an exhaust oxygen (O2) sensor, and a controller configured to perform a diagnostic routine for the fuel system during which fuel injectors of the fuel system do not need to be removed from the engine. The diagnostic routine comprises operating the engine at a set of predetermined operating points and detecting one or more malfunctions of one or more of the fuel injectors based on measured fuel rail pressure, measured engine speed, and measured O2 concentration at each of the set of predetermined operating points. Any fuel injector malfunctions detected during the diagnostic routine could be output to a diagnostic device operated by a human technician, e.g., in a single diagnostic report.

Methods and systems are provided for injector balancing without disabling a cam actuated high pressure fuel pump. In one example, one of a plurality of cam lobes of the pump is selectively and sequentially disabled while a group of injectors are concurrently operated to learn a pressure drop across each injector. The selection of the injectors is based on the identity and stroke timing of the disabled cam lobe.

Embodiments relate to an operating method for operating a fuel injection system of an internal combustion engine, wherein, upon a detection of a fault in the fuel injection system, and wherein a predefined pressure is overshot in a high-pressure region of the fuel injection system, an overrun mode of the internal combustion engine is deactivated, such that the internal combustion engine is operated exclusively in an injection mode.

Methods and systems are provided for reducing errors in estimated fuel rail pressure incurred at the time of a scheduled injection event due to engine-driven cyclic fuel rail pressure changes. In one example, a pulse-width commanded during a scheduled injection event is determined as a function fuel rail pressure samples collected over a moving window that is customized for the corresponding fuel injector. In another example, the commanded pulse-width is determined as a function of an average fuel rail pressure sampled during a quiet zone of injector operation and predicted fuel rail pressure altering events occurring between the quiet zone and the scheduled injection event.

Methods and systems are provided for reducing errors in estimated fuel rail pressure incurred at the time of a scheduled injection event due to engine-driven cyclic fuel rail pressure changes. In one example, a pulse-width commanded during a scheduled injection event is determined as a function fuel rail pressure samples collected over a moving window that is customized for the corresponding fuel injector. In another example, the commanded pulse-width is determined as a function of an average fuel rail pressure sampled during a quiet zone of injector operation and predicted fuel rail pressure altering events occurring between the quiet zone and the scheduled injection event.

A lower limit setting portion of a fuel pump control system sets a lower limit value depending on an engine operating mode. For example, it sets a duty ratio of 0% as the lower limit value, when the engine operating mode is in a STOP mode in a turned-on condition of an ignition switch. A duty-ratio calculating portion carries out a feedback control in order that an actual fuel pressure comes closer to a target fuel pressure by use of the lower limit value and calculates a duty ratio for driving a fuel pump by the feedback control. An abnormal condition determining portion determines an abnormal condition based on the duty ratio and pump current. The abnormal condition determining portion further determines based on a remaining fuel amount whether the abnormal condition is caused by a disconnection or whether the abnormal condition is caused by an idling operation of the fuel pump due to fuel shortage.

A method for matching the performance of a plurality of electronic fuel injectors, includes: applying a supply voltage to a control module; applying an operating voltage signal having a pulse width to each of the plurality of electronic fuel injectors individually via the control module; measuring an amount of time that each of the plurality of electronic fuel injectors supplies fuel; individually adjusting an operating voltage supplied to each of the plurality of electronic fuel injectors to cause each of the electronic fuel injectors to deliver fuel for a substantially same amount of time.

A lower limit setting portion of a fuel pump control system sets a lower limit value depending on an engine operating mode. For example, it sets a duty ratio of 0% as the lower limit value, when the engine operating mode is in a STOP mode in a turned-on condition of an ignition switch. A duty-ratio calculating portion carries out a feedback control in order that an actual fuel pressure comes closer to a target fuel pressure by use of the lower limit value and calculates a duty ratio for driving a fuel pump by the feedback control. An abnormal condition determining portion determines an abnormal condition based on the duty ratio and pump current. The abnormal condition determining portion further determines based on a remaining fuel amount whether the abnormal condition is caused by a disconnection or whether the abnormal condition is caused by an idling operation of the fuel pump due to fuel shortage.