The subject matter of this specification can be embodied in, among other things, a method for characterizing a fluid injector that includes receiving a collection of waveform data, identifying a pull locus, determining a detection threshold level value, identifying a first subset of the collection of data representative of a selected first electrical waveform of the collection of electrical waveforms, identifying an opening value, identifying a representative closing value, identifying an anchor value, identifying a second subset of the collection of data based on the collection of data, the pull locus, the first subset, and the opening value, identifying a maximum electrical value, identifying an opening locus based the collection of data, the anchor value, and the maximum electrical value, identifying a hold value, and providing characteristics associated with the fluid injector comprising the pull locus, the opening locus, the hold value, the anchor value, and the representative closing value.

A method for diagnosing a failure of a solenoid valve of a piston cooling device is provided. The method includes varying a pressure in a variable proportional control oil pump when an opening command or a closing command of the solenoid valve is sent to inject oil from the piston cooling device. Additionally, a variation of an oil pressure in an oil flow path of the piston cooling device is monitoring according to a variation of the pressure in the variable proportional control oil pump and whether a failure occurs at the solenoid valve of the piston cooling device is then determined.

A method of operating a fuel injector includes determining an actual energizing time correction value for a fuel injector at a first fuel rail pressure, calculating an extrapolated energizing time correction value by performing a mathematical calculation on the actual energizing time correction value, and controlling the operation of the fuel injector based on the actual energizing time correction value and the extrapolated energizing time correction value.

Methods and systems are provided for drying a wet-fouled spark plug during engine flooding conditions. In one example, a method may include, reverse rotating the engine unfueled and activating a heating element of an exhaust catalyst to flow heated ambient air through the combustion chamber to dry the wet-fouled spark plug.

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 is provided for monitoring the operation of intake valves of an internal combustion engine, where at least one or more cylinders of the engine have more than one intake valve, and adapted to operate in different modes where at least one of the intake valves for a particular cylinder can be selectively activated, or deactivated so as not to open during a firing sequence for the cylinder. The method includes a) monitoring the intake manifold air pressure; b) during a time window with respect to the intake phase for said respective cylinder, determining the condition of whether the manifold pressure drops by a threshold or to a particular threshold level; and c) determining the functionality of the intake valves dependent on the outcome of step b).

Provided is a method for diagnosing unintended fuelling from one or more fuel injectors of a multi cylinder internal combustion engine during engine operation. Pressurized fuel is intended to be distributed by means of said fuel injectors from said accumulator tank to the cylinders for combustion. An oxidation catalyst is arranged downstream said cylinders. The method comprises: determining the pressure in the fuel accumulator tank and whether said pressure is decreasing; and determining whether the actual amount of fuel provided by the pump unit exceeds the demanded amount of fuel. The method further comprises the steps of: determining whether the temperature associated with the oxidation catalyst is above a certain level and/or determining whether the air/fuel ratio is below a certain level and/or determining whether an amount of particulate matter is above a certain level; and confirming an unintended fuelling based on the determined conditions.

While an actuator is driven by an actuator driving unit with an operation amount for which the maximum value is limited by an operation amount limitation unit, if a state in which the actual opening degree of a wastegate valve does not coincide with a target opening degree has continued for a predetermined time period, driving by the actuator driving unit is attempted with an operation amount for which the maximum value limitation is relaxed by an operation amount limitation relaxing unit. Even after this, if the state in which the actual opening degree of the wastegate valve does not coincide with the target opening degree still has not been eliminated, an abnormality determination unit determines that abnormality has occurred in an opening degree control system for the wastegate valve.

Methods and systems are provided for using thermoelectric generators to recover waste heat from and diagnose turbocharger systems. In one example, a method may include adjusting one or more engine operating parameters based on an amount of current generated from one or more thermoelectric generators coupled to a turbocharger.

The present disclosure provides a method for learning emergency injection correction of an injector for preventing misfire. A misfire rate in a multi-stage injection mode is monitored, and it is controlled to be forcibly switched to a single injection mode when the misfire rate by the monitoring is equal to or greater than a specific value, such that injector injection correction learning is performed according to a learning entry condition. Accordingly, it is possible to reduce the deviation between cylinders by the sufficient injection amount deviation correction learning, thereby preventing misfire of the injector.