Ignition system and method controlling spark ignited combustion engines

A method for controlling an ignition system for spark ignited combustion engines, comprising:

• measuring a voltage applied over a control winding magnetically coupled to a secondary winding of an ignition coil;
• regulating the voltage over the control winding by regulating conductivity of an electronic switch in a linear region in transfer characteristics of the electronic switch during at least a part of a charge phase, an end of a spark phase, or at least during the subsequent combustion following end of spark phase,
• wherein, during the regulation of the voltage over the control winding, keeping the voltage over the control winding within at least one predetermined voltage interval reference such that impedance of the secondary winding of the ignition coil is influenced;
• and
• regulating the voltage over the control winding during a subsequent combustion following end of spark discharge,
• wherein, during the regulation of the voltage over the control winding, keeping the voltage over the control winding below at least one threshold level selected below a defined supply voltage level, improving ion sense capabilities and detection of high frequency content in an ion current signal during combustion.

A method for controlling an ignition system for spark ignited combustion engines, comprising:

• measuring a voltage applied over a control winding magnetically coupled to a secondary winding of an ignition coil,
• wherein an ion sense signal is measured in a circuit of the secondary winding representative for ionization degree in a spark plug gap connected to the secondary winding;
• regulating the voltage over the control winding by regulating conductivity of an electronic switch in a linear region in transfer characteristics of the electronic switch during at least a part of a charge phase, or an end of a spark phase or at least during the subsequent combustion following end of spark phase, during the regulation of the voltage over the control winding keeping the voltage over the control winding within at least one predetermined voltage interval reference such that impedance of the secondary winding of the ignition coil is influenced,
• wherein, during the regulation of the voltage over the control winding, keeping the voltage over the control winding within at least one predetermined voltage interval reference and below a voltage threshold level lower than a defined supply voltage level under at least a part of the charge phase or the spark phase or during the following combustion;
• and
• regulating the voltage over the control winding during a subsequent combustion following end of spark discharge,
• wherein during regulation of the voltage over the control winding keeping the voltage over the control winding below at least one threshold level selected below the nominal supply voltage level, ending the spark at onset of said regulation.