Abstract: An example method for operating an internal combustion engine may include: measuring pressure oscillations for a cylinder in the inlet tract at a defined operating point during normal operation; generating a corresponding oscillation signal; determining a crankshaft phase angle corresponding to the oscillation signal; and from the pressure oscillation signal, using discrete Fourier transformation to calculate the actual phase position of a selected signal frequency; determining a further comparison phase position in the same way from the selected signal frequency in the absence of fuel injection; calculating an actual phase position difference; on the basis of the difference, taking into consideration reference phase position differences of the same signal frequency for different fuel compositions, to identify a fuel composition of the presently used fuel; and adapting operating parameters of the engine based on the identified composition.

Abstract: A method for operating an internal combustion engine may include: measuring dynamic pressure oscillations in the inlet tract at a defined operating point during normal operation; generating a corresponding pressure oscillation signal; determining a crankshaft phase angle; determining an actual phase position using the pressure oscillation signal by discrete Fourier transformation; determining a chemical composition of the fuel using the determined actual phase position and reference phase positions of the same signal frequency for different fuel compositions; and adjusting operating parameters of the internal combustion engine based on the determined chemical composition.

Abstract: An example method for operating an internal combustion engine may include: measuring pressure oscillations for a cylinder in the inlet tract at a defined operating point during normal operation; generating a corresponding oscillation signal; determining a crankshaft phase angle corresponding to the oscillation signal; and from the pressure oscillation signal, using discrete Fourier transformation to calculate the actual phase position of a selected signal frequency; determining a further comparison phase position in the same way from the selected signal frequency in the absence of fuel injection; calculating an actual phase position difference; on the basis of the difference, taking into consideration reference phase position differences of the same signal frequency for different fuel compositions, to identify a fuel composition of the presently used fuel; and adapting operating parameters of the engine based on the identified composition.

Abstract: A method for operating an internal combustion engine may include: measuring dynamic pressure oscillations in the inlet tract at a defined operating point during normal operation; generating a corresponding pressure oscillation signal; determining a crankshaft phase angle; determining an actual phase position using the pressure oscillation signal by discrete Fourier transformation; determining a chemical composition of the fuel using the determined actual phase position and reference phase positions of the same signal frequency for different fuel compositions; and adjusting operating parameters of the internal combustion engine based on the determined chemical composition.

Abstract: Internal combustion engines which are operated using ethanol exhibit an improved capability for lean-burn running. The lean-burn running limit with a higher ethanol proportion is displaced in the direction of lean. This link between the lean-burn running limit and the ethanol proportion of the fuel is used to determine the ethanol proportion. To determine the lean-burn running limit, a fuel quantity is injected into a cylinder in the operating range of the overrun fuel cut-off, with which fuel quantity no combustion of the air/fuel mixture occurs, and the fuel quantity is increased continuously until combustion occurs; the smooth running of the engine is monitored for this cylinder and the lean-burn running limit is detected as reached if the smooth running exceeds a predefined threshold value. The ethanol proportion is then deduced from the increase in the injected fuel quantity which is required to reach the lean-burn running limit.

Abstract: Internal combustion engines which are operated using ethanol exhibit an improved capability for lean-burn running. The lean-burn running limit with a higher ethanol proportion is displaced in the direction of lean. This link between the lean-burn running limit and the ethanol proportion of the fuel is used to determine the ethanol proportion. To determine the lean-burn running limit, a fuel quantity is injected into a cylinder in the operating range of the overrun fuel cut-off, with which fuel quantity no combustion of the air/fuel mixture occurs, and the fuel quantity is increased continuously until combustion occurs; the smooth running of the engine is monitored for this cylinder and the lean-burn running limit is detected as reached if the smooth running exceeds a predefined threshold value. The ethanol proportion is then deduced from the increase in the injected fuel quantity which is required to reach the lean-burn running limit.

Abstract: A valve control for internal combustion engines comprising a hydraulic arrangement between a cam shaft and a cylinder head valve, the hydraulic arrangement including a piston system having at least a power piston cooperable with the cam shaft and an activating piston, a housing within which at least the actuating piston of the piston assembly is contained and a damping means for controlling valve seating operation. The hydraulic arrangement forms part of a means for varying the stroke and opening time of the cylinder head valve in response to at least one operating parameter of the internal combustion engine, and the means for varying the stroke and opening time also includes a throttle element for influencing the piston system, the throttle element being controlled by the noted at least one operating parameter of the internal combustion engine.