Technical data

11
7
Ionic current measurement
For optimized engine management in terms of
exhaust emission and fuel consumption, it is
necessary to establish as accurately as
possible the composition of the combustion
mixture under all engine operating conditions.
A method for achieving this aim is the so-
called ionic current measurement. Ionic
current measurement can be used for knock
combustion control and detecting irregular
idle speed (misfiring detection).
The ignition spark is triggered by the engine
control unit.
A low voltage is applied between the
electrodes of the spark plug immediately after
the end of the ignition spark and the resulting
current (ionic current) is measured.
The ionic current is measured and evaluated
by the ionic current control unit.
The combustion progression in the
combustion chamber can be represented by
the combustion chamber or
cylinder pressure curve.
4 - Ignition 5 - Ionic current measurement
Index Explanation
1 Spark plugs
2 Engine control unit
3 Ionic current control unit