A method for operating an internal combustion engine with a high pressure accumulator for a fuel injection system, includes the steps of: monitoring, in a time-dependent manner, a high pressure in the fuel injection system; conducting a check, at a high pressure-dependent starting time point, as to whether a continuous injection detection is to be carried out; and checking whether a high-pressure oscillation has occurred within an oscillation time interval prior to a starting time.

A method for testing a high-pressure pump, particularly a high-pressure pump which is provided to inject fuel into a combustion engine, the method including filling the high-pressure pump with a fluid prior to switching it on.

An electromagnetic control valve normality determination system includes: a hydraulic pressure source; an electromagnetic control valve structured to regulate an actual pressure of oil to a pressure command point, wherein the oil is supplied from the hydraulic pressure source; and an actual pressure sensor structured to sense the actual pressure of the oil. For determining normality of pressure regulation of the electromagnetic control valve, a normality determinator is configured to: set pressure command regions for determination about pressure regulation of the electromagnetic control valve, without overlapping among the pressure command regions; determine for each of the pressure command regions whether a difference between the actual pressure and the pressure command point in the each of the pressure command regions is less than a threshold value; and determine that the electromagnetic control valve is normal, in response to affirmation of the determination for all of the pressure command regions.

A system includes one or more processors that are configured to obtain a measured fuel consumption rate for an internal combustion engine while the engine is operating at a predetermined operating condition to perform a mission. The one or more processors are also configured to compare the measured fuel consumption rate with an expected fuel consumption rate for the predetermined operating condition. Further, the one or more processors are configured to determine whether an injector flow limiter is in a latched condition based on the measured fuel consumption rate compared with the expected fuel consumption rate. Also, the one or more processors are configured to perform a responsive action responsive to determining that the injector flow limiter is in the latched condition.

A system includes an exhaust aftertreatment system in exhaust gas receiving communication with an engine including a plurality of cylinders where the engine is structured to operate according to low load conditions and where a controller is structured to determine that at least one diesel emissions fluid (DEF) doser is frozen based on at least one of an ambient air temperature and a DEF source temperature. The controller is structured to operate the engine according to a skip-fire mode in response to a DEF flag indicating that the at least one DEF doser is frozen. The skip-fire mode comprises firing a portion of the plurality of cylinders that is less than a total amount of cylinders of the plurality of cylinders. The controller is structured to discontinue the skip-fire mode in response to determining that the at least one DEF doser is likely thawed.

A diagnostic system and method that (a) that uses models indicative of both successful firing and skips to determine if cylinders of a skip fire controlled internal combustion engine have successfully fired or successfully skipped and (b) uses filtered exhaust gas pressure readings for detecting faults associated with EGR systems and/or turbocharger systems.

Methods and systems are provided for maintaining combustion stability in a multi-fuel engine. In one example, a system may include first and second fuel systems to deliver liquid and gaseous fuels, respectively, to at least one cylinder of the engine, and a controller. The controller may be configured to supply the gaseous fuel to the at least one cylinder, inject the liquid fuel to the at least one cylinder to compression ignite the liquid fuel and combust the gaseous fuel in the at least one cylinder, and retard an injection timing of the injection of the liquid fuel based on a measured parameter associated with auto-ignition of end gases subsequent to the compression-ignition of the liquid fuel. In some examples, the controller may further be configured to adjust an amount of the gaseous fuel relative to an amount of the liquid fuel based on the measured parameter.

An injection control device includes: a drive control unit that controls energization by correcting an energization instruction time when injecting the fuel by executing the current-drive, and includes an energization time correction amount calculation unit that calculates an energization time correction amount by performing area correction on a current flowing through the fuel injection valve; an abnormality determination unit that determines an abnormality in a control system of the drive control unit; and a correction amount subtraction setting unit that stops a calculation of the energization time correction amount when the abnormality determination unit determines an abnormality, and controls the drive control unit to directly or stepwise reduce the energization time correction amount at an abnormality determination.

An injection control device includes: an area correction unit that calculates an energization time correction amount when executing a current drive of the fuel injection valve to inject a fuel from the fuel injection valve; an estimation unit that independently calculates an estimated energization time correction amount; a comparison unit that compares the energization time correction amount c with the estimated energization time correction amount; and a first abnormality determination unit that determines that the energization time correction amount is abnormal.

Various methods and systems are provided for health assessments of a fuel system. In one example, a method for an inlet metering valve (IMV) includes reducing electrical driving of the IMV, monitoring a response time of the IMV in real-time responsive to the reducing, and determining if the IMV is degraded based on a response of IMV current over a duration, the duration beginning after an initial decrease in current caused by the reducing.