A method of predicting and controlling NOx generation amount is provided. The method includes calculating a difference between an actual and a reference NOx exhaust amount and analyzing influence of the in-cylinder pressure at a combustion start time, an oxygen amount in EGR gas, and a fuel injection timing. A NOx rate of change is calculated based on change in the in-cylinder pressure at the combustion start time, the oxygen amount in the EGR gas, and the fuel injection timing. A variation width and a NOx value are calculated at the combustion start time, the oxygen amount in the EGR gas, and the fuel injection timing. The NOx value is adjusted based on the NOx value adjustment amount and a NOx final value is determined. A target boost pressure, a target oxygen amount, and a target fuel injection timing are determined to provide a final command signal.

A method of controlling a fuel injection of a diesel engine for performing a plurality of fuel injections to cause a plurality of combustions inside a cylinder in one combustion cycle, is provided, which includes performing, on compression stroke, the plurality of fuel injections at substantially constant injection intervals while increasing an injection amount as an in-cylinder oxygen concentration decreases, and performing, after the plurality of fuel injections, another fuel injection including a larger injection amount than in the plurality of fuel injections near a top dead center of the compression stroke.

A method of controlling a fuel injection of a diesel engine for performing a plurality of fuel injections to cause a plurality of combustions inside a cylinder in one combustion cycle, is provided, which includes acquiring an oxygen concentration inside the cylinder, performing, on compression stroke, the plurality of fuel injections at substantially even injection intervals while increasing the injection intervals as the oxygen concentration decreases, and performing, after the plurality of fuel injections, another fuel injection including a larger injection amount than in the plurality of fuel injections, near a top dead center of the compression stroke.

A characteristic determining device is provided which determines fuel injection characteristics of a plurality of fuel injectors for an internal combustion engine. The characteristic determining device includes a pressure sensor and a plurality of pipes each of which connects between the pressure sensor and one of the fuel injectors. The pressure sensor is designed to have a plurality of pressure inputs from the respective fuel injectors through the pipes and outputs a signal indicative of a level of pressure in each of the fuel injectors. The characteristic determining device analyzes the signals from the first pressure sensor to determine the fuel injection characteristics of the respective fuel injectors. These arrangements result in a simplified structure of the characteristic determining device and a decreased manufacturing cost thereof.

The present invention discloses a method of operating an internal combustion engine comprising a controllable injector for injecting fuel into a combustion chamber, the injector communicating with a fuel accumulator through which it is supplied with fuel, the method comprising the following steps: determining a first pressure value of the pressure in the fuel accumulator on the basis of a first pressure measurement, determining a second pressure value of the pressure in the fuel accumulator on the basis of a second pressure measurement carried out after the first pressure measurement, and determining an injector opening duration depending on the first and the second pressure value.

The invention relates to a method (100) for operating a solenoid valve (1) for metering a fuel (2) in a fuel injection system (3). The solenoid valve can be actuated against a restoring force (12) by an electromagnet (11), wherein the time curve l(t) of the current I flowing through the electromagnet (11) and/or the time curve U(t) of the voltage U applied to the electromagnet (11) are detected during at least one opening process of the solenoid valve (1). The opening time t.sub.ON and the closing time t.sub.OFF of the solenoid valve (1) are evaluated (110) from the time curve I(t) and/or U(t), and the actual opening duration T.sub.T=t.sub.OFFt.sub.ON of the solenoid valve (1) is compared (140) with a reference value T.sub.R and/or the mass flow dm/dt flowing through the solenoid valve (1) is detected (120) and compared (142) with a reference value M.sub.R during at least one opening process of the solenoid valve (1); and/or a leakage dm/dt of fuel (2) through the solenoid valve (1) is detected (130) in the closed state of the solenoid valve (1). The invention also relates to a corresponding controller (5), a fuel injection system (3), and a computer program product.

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.

A fuel system for an internal combustion engine includes a fuel control system having a fueling control unit structured to determine a test point on a tip wear-sensitive region of a fuel injector delivery curve, and store measurements of pressure drops in a pressurized fuel reservoir caused by injections of fuel at the test point. The fueling control unit is further structured to produce an injector health signal based on the stored measurements of pressure drop. Related methodology and control logic for calculation of wear parameters for injection signal duration electronic trimming and prognostic health determinations are also disclosed.

Provided are methods and fuel injection systems implemented with a plurality of injectors coupled with a common rail, the common rail coupled with a pressure sensor, and the pressure sensor coupled with a processor. The method includes: identifying, by the processor, one of the injectors to calculate a pressure change rate of the common rail associated therewith; receiving, by the processor, pressure measurements of the common rail from the pressure sensor before and during an injection event within a measurement window; using, by the processor, a pre-injection mean pressure of the common rail to determine a rail pressure drop range that is specific to the identified injector; and calculating, by the processor, the pressure change rate associated with the identified injector based on the pressure measurements of the common rail taken during the rail pressure drop range.

A determination method of opening characteristics of a fuel injector in an internal combustion engine comprising a knock sensor capable of generating a signal representative of vibrations. The knock sensor is used to determine the opening characteristics of the fuel injector. The determination method comprises acquiring the knock sensor signal over a predetermined measurement window synchronised on an injection control signal; and analysing the sensor signal over the measurement window in order to determine a first alternation of a first wave train and to determine the local maximum of the first alternation. The fuel injection is controlled based on the opening characteristic of the injector determined based on this local maximum.