Abstract: Various embodiments may include a method for operating an internal combustion engine comprising: measuring pressure oscillations assignable to a cylinder in the inlet tract at a defined operating point during normal operation; generating a corresponding pressure signal; determining a corresponding crankshaft phase angle; calculating an injection signal component caused by fuel injection by subtracting a reference base pressure oscillation signal; determining a signal phase position and a signal amplitude of the injection signal component; determining an injection start time; determining an injection quantity on the basis of the signal amplitude and reference amplitudes; and adapting operation of the internal combustion engine based on the determined injection quantity.

Abstract: The present disclosure relates to internal combustion engines and its teachings may be embodied in methods for controlling and identifying valve control times of an internal combustion engine. Some embodiments may include a method comprising: measuring dynamic pressure oscillations in the inlet section or outlet section of the respective series-production engine; determining a crankshaft-position feedback signal; determining the phase angles of selected signal frequencies using discrete Fourier transformation; and determining the valve control times of the respective series-production internal combustion engine based on the determined phase angles, the reference phase angles, and reference valve control times with the same signal frequencies of the pressure oscillations of a reference internal combustion engine or of a model function derived therefrom.

Abstract: Various embodiments may adjust fuel injections to account for phase differences of the piston stroke and the valve strokes of a reciprocating-piston engine. For example: measuring dynamic pressure oscillations assigned of the air in the intake tract or the gas in the outlet tract; determining a crankshaft phase angle signal; determining the phase positions of selected signal frequencies of the oscillations in relation to the signal; determining lines of equal phase positions based on the phase positions of the selected frequencies; determining a common intersection point of the lines by projection into a common plane spanned by inlet valve stroke phase difference and outlet valve stroke phase difference and signal-frequency-dependent phase shifting; determining the inlet and outlet phase difference from the common intersection point; determining the piston stroke phase difference from the phase shift; and adjusting an amount of a fuel injection based on the determined differences.

Abstract: Various embodiments may include a method for operating an internal combustion engine comprising: measuring pressure oscillations assignable to a cylinder in the inlet tract at a defined operating point during normal operation; generating a corresponding pressure signal; determining a corresponding crankshaft phase angle; calculating an injection signal component caused by fuel injection by subtracting a reference base pressure oscillation signal; determining a signal phase position and a signal amplitude of the injection signal component; determining an injection start time; determining an injection quantity on the basis of the signal amplitude and reference amplitudes; and adapting operation of the internal combustion engine based on the determined injection quantity.

Abstract: Various embodiments may adjust fuel injections to account for phase differences of the piston stroke and the valve strokes of a reciprocating-piston engine. For example: measuring dynamic pressure oscillations assigned of the air in the intake tract or the gas in the outlet tract; determining a crankshaft phase angle signal; determining the phase positions of selected signal frequencies of the oscillations in relation to the signal; determining lines of equal phase positions based on the phase positions of the selected frequencies; determining a common intersection point of the lines by projection into a common plane spanned by inlet valve stroke phase difference and outlet valve stroke phase difference and signal-frequency-dependent phase shifting; determining the inlet and outlet phase difference from the common intersection point; determining the piston stroke phase difference from the phase shift; and adjusting an amount of a fuel injection based on the determined differences.

Abstract: The present disclosure relates to internal combustion engines and its teachings may be embodied in methods for controlling and identifying valve control times of an internal combustion engine. Some embodiments may include a method comprising: measuring dynamic pressure oscillations in the inlet section or outlet section of the respective series-production engine; determining a crankshaft-position feedback signal; determining the phase angles of selected signal frequencies using discrete Fourier transformation; and determining the valve control times of the respective series-production internal combustion engine based on the determined phase angles, the reference phase angles, and reference valve control times with the same signal frequencies of the pressure oscillations of a reference internal combustion engine or of a model function derived therefrom.

Abstract: A method for controlling a variable valve train of an internal combustion engine including multiple cylinders is disclosed. At a first operating point of the engine, an intake air amount is determined and cylinder-individual values for a fuel amount reduction are determined by successively reducing the respectively supplied fuel amount for each cylinder until a characteristic representing uneven running of the engine has reached a predetermined uneven running threshold value. A ratio of a change in the intake valve lift to the resulting change in the intake air amount is determined for the first operating point. Cylinder-individual deviations of the intake valve lift from a reference value are determined based on the ratio, the intake air amount at the first operating point, and the associated value for the fuel amount reduction. The variable valve train is then controlled on the basis of the cylinder-individual deviations of the intake valve lift.

Abstract: A method for controlling a variable valve train of an internal combustion engine including multiple cylinders is disclosed. At a first operating point of the engine, an intake air amount is determined and cylinder-individual values for a fuel amount reduction are determined by successively reducing the respectively supplied fuel amount for each cylinder until a characteristic representing uneven running of the engine has reached a predetermined uneven running threshold value. A ratio of a change in the intake valve lift to the resulting change in the intake air amount is determined for the first operating point. Cylinder-individual deviations of the intake valve lift from a reference value are determined based on the ratio, the intake air amount at the first operating point, and the associated value for the fuel amount reduction. The variable valve train is then controlled on the basis of the cylinder-individual deviations of the intake valve lift.

Abstract: In a method for operating an internal combustion engine having an intake tract and one injection valve per cylinder, a lambda controller having an associated lambda sensor for correcting an air-fuel ratio in the combustion chamber, an engine operating temperature is detected and a air mass target value in the combustion chamber is determined as a function of an engine operating state. When the lambda controller is deactivated, a first adaptation value is determined as a function of the captured operating temperature, of the determined air mass target value, and a prescribed first weighting value. A second adaptation value is further determined as a function of the determined air mass target value and a prescribed second weighting value. The metering of the fuel mass and/or a model of the air mass fed into the combustion chamber is corrected as a function of the first and second adaptation value.

Abstract: An internal combustion engine has a plurality of cylinders that have been allocated in at least two groups to one exhaust gas tract each. In each exhaust gas tract, an exhaust gas catalytic converter and an exhaust gas probe are fitted upstream of the exhaust gas catalytic converter. In order to detect combustion misfires in a combustion chamber of one of the cylinders, the following steps are carried out in each case. A combustion misfire is detected in one of the cylinders and allocated to one of the groups of the cylinders depending on at least one operating variable of the internal combustion engine.

Abstract: An internal combustion engine has a plurality of cylinders that have been allocated in at least two groups to one exhaust gas tract each. In each exhaust gas tract, an exhaust gas catalytic converter and an exhaust gas probe are fitted upstream of the exhaust gas catalytic converter. In order to detect combustion misfires in a combustion chamber of one of the cylinders, the following steps are carried out in each case. A combustion misfire is detected in one of the cylinders and allocated to one of the groups of the cylinders depending on at least one operating variable of the internal combustion engine.