Abstract: A method is provided for operating an ignition device for an internal combustion engine, which ignition device includes an ignition coil configured as a transformer, a spark plug connected to the secondary winding of the ignition coil, an actuable switching element connected in series to the primary winding of the ignition coil, and a control unit connected to the control input of the switching element, wherein the control unit provides an adjustable supply voltage for the ignition coil and an actuating signal for the switching element as a function of the currents through the primary and the secondary windings of the ignition coil and the voltage between the connecting point of the primary winding of the ignition coil to the switching element and the negative terminal of the supply voltage, as a result of which firstly operation of the spark plug by way of alternating current is possible and secondly regulation of said current is possible, which leads to more reliable ignition with a lower wear of the spark

Abstract: A method is provided for operating an ignition device for an internal combustion engine, which ignition device includes an ignition coil configured as a transformer, a spark plug connected to the secondary winding of the ignition coil, an actuable switching element connected in series to the primary winding of the ignition coil, and a control unit connected to the control input of the switching element, wherein the control unit provides an adjustable supply voltage for the ignition coil and an actuating signal for the switching element as a function of the currents through the primary and the secondary windings of the ignition coil and the voltage between the connecting point of the primary winding of the ignition coil to the switching element and the negative terminal of the supply voltage, as a result of which firstly operation of the spark plug by way of alternating current is possible and secondly regulation of said current is possible, which leads to more reliable ignition with a lower wear of the spark

Abstract: For monitoring a combustion process in an internal combustion engine wherein a fuel-air mixture is ignited with a high-frequency plasma it is provided to determine the impedance of the plasma. A high-frequency signal is applied to the resonator with a capacity that is so low that no arcing-over forms on the electrodes and the high-frequency current and the high-frequency voltage are measured. The impedance of the ignited mixture is determined from the high-frequency current and the high-frequency voltage.

Abstract: For monitoring a combustion process in an internal combustion engine wherein a fuel-air mixture is ignited with a high-frequency plasma it is provided to determine the impedance of the plasma. A high-frequency signal is applied to the resonator with a capacity that is so low that no arcing-over forms on the electrodes and the high-frequency current and the high-frequency voltage are measured. The impedance of the ignited mixture is determined from the high-frequency current and the high-frequency voltage.