A control system includes a controller. The controller acquires a crank counter value each time a fixed time elapses. The controller calculates the number of the crank counter values corresponding to the top dead center of the plunger between a previously acquired crank counter value and a currently acquired crank counter value with reference to the map each time the crank counter value is acquired and calculate the number of driving times of the high pressure fuel pump by integrating the calculated number.

A control system includes a controller. The controller estimates the swing-back amount indicating the turning amount of the crankshaft in the reverse rotation direction until the crankshaft stops. The controller calculates a stop-time counter value which is a value of a crank counter at the time when the engine is stopped based on a final counter value which is the value of the crank counter calculated last before the crankshaft stops and the estimated swing-back amount. The controller corrects the swing-back amount used for calculating the stop-time counter value based on a difference between the number of driving times calculated with reference to the map based on the calculated stop-time counter value and the value of the crank counter and the number of driving times calculated by increasing the number of driving times by one each time the high pressure system fuel pressure increases by the threshold or more.

A method for detecting continuous injection during the operation of an internal combustion engine with an injection system having a high-pressure accumulator for a fuel, whereina high pressure in the injection system is monitored as a function of time, whereinin order to detect continuous injection it is checked whether the high pressure has dropped by a predetermined continuous injection differential pressure value within a predetermined continuous injection time interval, whereinit is checked whether a reduction valve which connects the high-pressure accumulator to a fuel reservoir has been triggered, and whereincontinuous injection is detected ifa reduction valve has not been triggered in a predetermined checking time interval before the dropping of the high pressure, and ifthe high pressure has dropped by the predetermined continuous injection differential value amount within the predetermined continuous injection time interval.

Methods and systems are disclosed for operating an engine that includes a knock control system. The method and system may increase opportunities to learn one or more engine knock background noise levels via changing poppet valve timing and/or fuel injection timing. The method and system may also improve knock detection if knock sensor degradation is suspected.

An unequal-interval combustion engine misfire-determination device determines whether a misfire has occurred in an unequal-interval combustion engine including a plurality of cylinders in which combustion occurs at unequal intervals. The misfire determination device includes: an unequal interval combustion fluctuation canceled value acquisition unit that acquires, based on a crank angle signal, an unequal interval combustion fluctuation canceled value which is a rotation speed in a section of 720m crank angle degrees including a predetermined determination angle position, where m is a natural number; an unequal interval combustion fluctuation manifested value calculation unit that calculates an unequal interval combustion fluctuation manifested value in which a fluctuation component attributable to unequal interval combustion is manifested, by removing the unequal interval combustion fluctuation canceled value; and a specific cylinder misfire determination unit that determines a misfire in a specific cylinder based on the unequal interval combustion fluctuation manifested value.

A means of detecting the in-situ fuel-to-air-ratio (FAR) in a combustor or flame zone using a Fourier-based flame ionization probe is presented. The use of multiple excitation frequencies and its detection at certain frequencies or combinations of harmonics of those excitation frequencies, namely, the inter-modulation distortion, provides a novel means of extracting a high signal-to-noise ratio (SNR) FAR measurement in a combustor.

A method for determining the quantity of filling components in a cylinder of an internal combustion engine. The cylinder is connected to an air supply via an inlet valve and to an exhaust gas conduit via an outlet valve. The method includes the steps of obtaining an exhaust gas back pressure at a specified point in time when the outlet valve is opened during a work cycle of the internal combustion engine and calculating the quantity of the filling components at the specified point in time on the basis of the obtained exhaust gas back pressure. A controller is also provided for carrying out the method and a motor vehicle is also provided that includes the controller.

Methods and systems are disclosed for operating an engine that includes a knock control system. The method and system may increase opportunities to learn one or more engine knock background noise levels via changing poppet valve timing and/or fuel injection timing. The method and system may also improve knock detection if knock sensor degradation is suspected.

Methods and systems are provided for operating a variable displacement engine that includes a knock control system. Fuel injection timing and cylinder firing patterns may be adjusted to maintain engine background noise levels so that the presence or absence of engine knock may be more reliably detected. Further, select variable engine displacement modes may be avoided so that engine background noise level changes may be reduced to improve engine knock detection.

An air-fuel ratio sensor control apparatus comprises a voltage control part configured to control a voltage Vo1 applied to a cell of an air-fuel ratio sensor in accordance with a sensor current flowing in the cell and a current detection part configured to detect the sensor current as a physical value, which indicates the air-fuel ratio. In the air-fuel ratio sensor control apparatus, a voltage varying time point, at which the voltage control part varies the voltage Vo1, and a current detecting time point, at which the current detection part detects the current, are shifted from each other. A time period Ta from the current detecting time point, which is immediately before the voltage varying time point, to the voltage varying time point and a time period Tb from the voltage varying time point to the current detecting time period, which is immediately after the voltage varying time point, are set to satisfy Ta<Tb.