A method for ascertaining a variable characterizing a flow rate of a fuel injector during an operation of an internal combustion engine, to which the fuel injector is assigned. At least two input values for a data-based model are ascertained, and at least one output value is determined with the aid of the data-based model, on the basis of which a value for the variable characterizing the flow rate of the fuel injector is ascertained. The data-based model combines at least two methods differing from one another for ascertaining a variable characterizing a flow rate of a fuel injector.

Various embodiments of the present disclosure relate to methods and systems for measuring an injected fuel quantity during multipulse injection events in a common rail of a fuel system including a fuel pump to supply fuel to the common rail. The method, using a control unit, determines if each of the multipulse injection events in a normal operating condition includes a pilot pulse, in response to determining that the pilot pulse is included, obtaining an enforced separation value between the pilot pulse and the main pulse to emulate a single-pulse injection; while the fuel pump is temporarily shut off, performing a temporary enforced separation on a fraction of the multipulse injection events; measuring a pressure change in the common rail during the temporary enforced separation; and resuming the normal operating condition of the multipulse injection events after the pressure change is measured.

A method of controlling an engine system includes controlling a fuel injector to perform a zero-fueling injector operation during operation of the engine, the zero-fueling injector operation including a non-zero injector on-time resulting in zero fueling by the injector, determining an injection system pressure change associated with the zero-fueling injector operation, modifying at least one fuel injection control parameter in response to the injection system pressure change, and using the modified fuel injection control parameter to control injection of fuel by the fuel injector during operation of the engine.

A method of generating an ROI profile for a fuel injector using machine learning and a constrained/limited training data set is disclosed. The method includes receiving a first plurality of measurement sets for a fuel injector when operating at a first target set point. Preferably, at least two measurement sets of the first plurality of measurement sets are selected to generate a first averaged ROI profile for the first target condition. The at least two selected measurement sets are then used to train a machine learning model that can output a predicted ROI profile for a fuel injector based on a desired pressure value and/or desired mass flow rate value. Training of the machine learning model preferably includes a predetermined number of iterations that induces overfitting within the model/neural network.

The invention relates to a maintenance system for a fuel injection system provided in an internal combustion engine, the fuel injection system defining a hydraulic circuit having a high-pressure pump, a solenoid valve, a pressure sensor, a metering solenoid valve, a common rail and injectors. The maintenance system includes a manual control unit connected to a hydraulic unit, the hydraulic unit being capable of being inserted into the hydraulic circuit of the fuel injection system and including a test solenoid valve and a test pressure sensor mounted in a body provided with an inlet mouth, an outlet mouth and a leakage mouth.

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 method and system for correcting a fuel injection amount that injects fuel may include applying a current value for injecting a target fuel amount and injecting fuel under a driving condition in which fuel injection is blocked; determining a frequency analysis value for a pressure signal of the fuel pressure rail when the fuel is injected; determining a fuel amount difference corresponding to a difference value between the frequency analysis value and a reference frequency analysis value stored in a data storage in advance; and correcting a current value of the injector which is applied to inject the target fuel amount to remove the fuel amount difference.

A method of controlling an engine system includes controlling a fuel injector to perform a zero-fueling injector operation during operation of the engine, the zero-fueling injector operation including a non-zero injector on-time resulting in zero fueling by the injector, determining an injection system pressure change associated with the zero-fueling injector operation, modifying at least one fuel injection control parameter in response to the injection system pressure change, and using the modified fuel injection control parameter to control injection of fuel by the fuel injector during operation of the engine.

The invention relates to a maintenance system for a fuel injection system provided in an internal combustion engine, the fuel injection system defining a hydraulic circuit having a high-pressure pump, a solenoid valve, a pressure sensor, a metering solenoid valve, a common rail and injectors. The maintenance system includes a manual control unit connected to a hydraulic unit, the hydraulic unit being capable of being inserted into the hydraulic circuit of the fuel injection system and including a test solenoid valve and a test pressure sensor mounted in a body provided with an inlet mouth, an outlet mouth and a leakage mouth.

A pressure measurement device for determining a pressure of a fluid located inside a cylindrical casing includes: at least one sensor for determining a force acting thereon; and a clamp for peripheral attachment to the casing. The at least one sensor is arranged inside the clamp and is operatively connected thereto. The clamp includes a peripheral link chain having chain links that are pivotably coupled to one another at end joints, and a closure device that interacts with a first chain link and a final chain link.