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.

At least some embodiments of present disclosure direct to a fuel injection timing drift detection and/or compensation system. In some cases, the system collects or receives a series of fuel pressure data measured by one or more fuel pressure sensors. The system is configured to receive an indication of fuel flow cutout and a start-of-injection command signal. The system calculates a set of pressure drops using the series of fuel pressure data and identifies a selected pressure drop greater than a predetermined threshold to determine a measured start-of-injection timing based on the selected pressure drop. The system is further configured to evaluate whether a fuel injection drifting occurs based on received start-of-injection command signal and the measured start-of-injection timing. In some cases, the fuel injection drifting is used to either compensate fuel injection timing or raise a flag indicating the drifting.

The invention relates to a method for operating a fuel injection system (1) for supplying a combustion engine of a vehicle with fuel, in which method the fuel is conveyed at high pressure with the aid of a high-pressure pump (2), fed to a high-pressure accumulator (3), and injected into a cylinder of the combustion engine with the aid of at least one injector connected to the high-pressure accumulator (3). In order to detect any damage to the drive of the high-pressure pump (3), according to the invention a) the pressure (P) in the high-pressure accumulator (3) is measured and, on the basis of the measured values, a pressure drop (P) in the high-pressure accumulator (3) caused by an injection into a cylinder is determined, b) a maximum pressure gradient is determined during a pressure build-up phase following the injection, c) the determined pressure drop (P) and the determined maximum pressure gradient are put into proportion. The invention further relates to an electronic control unit for carrying out the method.

A measuring system, method, and/or computer program that realizes physics-based relations between sensor readings to monitor for degradations and predict failures of power systems is provided. For example, the supply and return of fuel in a power system is provided by a fuel injection system. The fuel injection system responds to changes in loads and system conditions, such as to compensate for fuel loss due to fuel combustion, by continuously and instantaneously changing the fuel flow. This behavior by the fuel injection system creates characteristic signatures. These characteristic signatures are instantaneously detected and utilized by the measuring system, method, and/or computer program to detect healthy, degrading, failing, and failed mechanical conditions so as to monitor for degradations and predict failures of the power system.

A fuel-filter abnormality detection device is used for a subject filter provided in a fuel supply device of an engine to filtrate a fuel. The fuel-filter abnormality detection device includes a first filter attachable downstream of the subject filter in fuel flow. A filtration capacity of the first filter is smaller than a filtration capacity of the subject filter, and the first filter traps a foreign matter on a downstream side of the subject filter to cause a change in fuel pressure indicating an abnormality of the subject filter. The fuel-filter abnormality detection device may include a bypass passage through which the fuel bypasses the first filter, a bypass control valve configured to allow the fuel to flow through the bypass passage when the abnormality of the subject filter is detected, and a second filter filtrating the fuel flowing through the bypass passage.

When imbalance diagnosis is not executed, target fuel pressure is set based on a rotation speed and volumetric efficiency of an engine, and when the imbalance diagnosis is executed, fuel pressure smaller than the target fuel pressure settable when the imbalance diagnosis is not executed is set as the target fuel pressure, and a high-pressure fuel pump that supplies fuel to a delivery pipe connected to the in-cylinder injection valve, is driven and controlled such that detected fuel pressure becomes the target fuel pressure. With this, it is possible to execute the imbalance diagnosis with higher accuracy.

In an embodiment, a pressure sensor includes a tip secured to a port. The tip includes an opening for receiving pressure to be measured by the pressure sensor. The port includes a threaded section for mounting the pressure sensor in a fixture such as, for example, a rail. The port also includes a flexible section, a cavity, and an opening. The opening in the tip receives pressure from an outside source and channels the pressure to the opening of the port. The opening of the port receives the pressure from the tip and channels the pressure to the cavity. The pressure received in the cavity applies a force to the flexible section which flexes in response to the force. Moreover, forces are provided by the tip and the threaded section to keep the tip secured to the port.

A fuel injection apparatus includes: a first obtaining unit that obtains a first index relating to an opening behavior of an injector; a second obtaining unit that obtains at least one of a second index relating to a maximum injection rate of the injector and a third index relating to an injection period; and a calculation unit that determines that injection hole corrosion has occurred in the injector when a first condition relating to the first index is established and at least one of a second condition relating to the second index and a third condition relating to the third index is established.

Methods and systems are provided for processing of an on-board diagnostic (OBD) test dataset, and transferring parameters of a curve fit to the processed data to an off-board location. In one example, a method may include performing an evaporative emissions system diagnostic test, fitting a curve to at least a part of the data, transferring parameters of the curve fit, along with the start, and end data points to an off-board location for further processing. The on-board controller may adjust engine operating conditions based on signal received from the off-board location after off-board data reconstruction, and analysis.

Various methods and systems are provided for diagnosing a condition of a fuel injector of an engine. In one example, a method for an engine includes injecting a first pulse of fuel as a first pilot injection into a first subset of cylinders of a plurality of engine cylinders, where the first pilot injection precedes a primary injection of fuel into the first subset of cylinders by a duration; correlating a first response in an engine operating parameter to the first pilot injection; and adjusting the primary injection of fuel into the first subset of cylinders based on the first response. In one example, the first pilot injection precedes the primary injection by a predefined short duration and the primary injection of fuel is adjusted within a predefined or preset upper limit and lower limit.