A controller for an internal combustion engine is configured to execute: a process of switching the injection mode according to an engine operational state; an anomaly determination process of determining whether there is an anomaly in the injection system that is implementing a single injection mode during implementation of the single injection mode; a provisional determination process of provisionally determining whether there may be an anomaly in the injection system that is implementing the single injection mode during the implementation of the single injection mode; and an idle determination process of, if it is determined that there is an anomaly in the provisional determination process, prohibiting the automatic stop and executing, during an idle operation, the anomaly determination process by implementing an injection mode that uses only the injection system provisionally determined to have an anomaly in the provisional determination process.

A method for checking the operation of a high-pressure fuel supply unit for an internal combustion engine, consisting in driving a high-pressure fuel injection pump by a starter, and after the engine is synchronised and fuel injection into the cylinders is shut off, in defining an initial base pressure in a high-pressure rail, in activating the injection pump by issuing successive timing and angle-setting commands, on the basis of the initial pressure, and in comparing the first pressure and the second pressure obtained in the rail by these timing and angle-setting commands, and/or by comparing at least one of the pressures with a reference pressure in order to check the operation of the high-pressure fuel supply unit for the internal combustion engine.

Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a high-pressure fuel pump operable to increase fuel pressure from a first pressure to a second pressure, a common fuel rail fluidly coupling the high-pressure fuel pump to a plurality of fuel injectors each of which is operable to inject fuel to individual cylinders of an engine, a pressure sensor operable to detect a pressure of fuel at the common fuel rail, and a controller operable to diagnose a condition of the high-pressure fuel pump based on output from the pressure sensor.

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.

A method and apparatus for in situ operating an internal combustion engine comprising determining at least one combustion characteristic for a combustion chamber of the internal combustion engine, comprising an actual heat release signal for the combustion chamber; and inputting the actual heat release signal into a diagnostic logic tree for diagnosing changes in combustion characteristics due to at least one of: a malfunctioning fuel injector, a start of combustion timing error; and a change in fuel quality; and performing a mitigation technique to compensate for the changes in combustion characteristics.

An ECU functioning as a diagnostic device includes an information acquisition portion acquiring a flow rate of a fluid flowing through an intake pipe, and a diagnostic portion performing a diagnosis on a second purge pipe employed as a fuel gas pipe regarding a connection failure. The diagnostic portion diagnoses a connection failure of the fuel gas pipe according to magnitude of a pulsation of the flow rate acquired by the information acquisition portion.

A method for operating a fluid delivery system of a vehicle powerplant is provided. The method includes sampling a fluid pressure in a port injection section of the fluid delivery system, determining if an isolation valve positioned upstream of a direct injection pump is degraded based on the fluid pressure, where the isolation valve separates the port injection section from a direct injection section, and when it is determined that the isolation valve is degraded, indicating said degradation of the isolation valve.

A lean operation fault detection and isolation (FDI) technique involves receiving, from a manifold absolute pressure (MAP) sensor, a measured MAP, detecting a lean operation fault where an engine is operating with a lean air/fuel ratio, estimating, using an observer, (i) an air/fuel ratio of an exhaust gas produced by the engine and (ii) the MAP, monitoring first and second residual values indicative of differences between (i) the estimated air/fuel ratio of the exhaust gas and a measured air/fuel ratio of the exhaust gas from an exhaust O2 sensor and (ii) the estimated MAP and the measured MAP from the MAP sensor, respectively, and, based on the monitoring of the first and second residual values, determining which of (i) an air intake of the engine, (ii) the exhaust O2 sensor, and (iii) a fuel injector of the engine is malfunctioning and causing the lean operation fault.

A method for monitoring fuel quality of a power system used in transport is provided. The method includes a controller of the power system determining that the prime mover is actively running. The method also includes the controller monitoring an output of a water-in-fuel (WIF) sensor configured to measure an amount of water accumulated in a water collection reservoir of a fuel/water separator that separates water from fuel passing there through. Also, the method includes the controller determining an amount of fuel passing through the fuel/water separator. Further, the method includes the controller calculating a fuel quality score of the fuel based on the output of the WIF sensor and the amount of fuel having passed through the fuel/water separator. The method further includes the controller triggering different alerts based on the calculated fuel quality score.

Method and system for detecting a high friction within a flow control device of a fuel system are disclosed. For example, the method includes receiving a service test sequence to execute a service test, performing, in response to receiving the service test sequence, the service test to generate test data, the service test including a first test cycle with a first dither level and a second test cycle with a second dither level, wherein the second dither level is different from the first dither level. The method further includes determining whether a performance difference between the first test cycle and the second test cycle exceeds a predetermined threshold based on the test data and detecting, in response to determining that the performance difference exceeds the predetermined threshold, a presence of high friction within the flow control device.