The ionic current control units use the conductance of the mixture between the electrodes of the spark plugs to measure the following variables:
The duration of spark combustion is measured after the ignition spark has been triggered. During ignition sparking, the conductance is very high, and this enables detection of the ignition spark. The unit is ms.
The duration of spark combustion varies in a value range of 0.1 to 1.5. If the ignition spark fails, the value falls to 0.1.
The combustion quality is measured after the end of the ignition spark. To this end, the integral over the duration of combustion is formed. The unit is nSs (nano Siemens seconds; Siemens is the unit for conductance).
The combustion quality varies in a value range of 0-5. When no combustion is taking place, the value falls to 0.