Detecting knocking in an internal combustion engine with immediate normalization of an ionic current

A procedure for the recognition of pinking in the operation of an internal combustion engine has an raw ion current signal measured during the combustion stroke in the combustion chambers by an ion current sensor. From this, a value of the pinking intensity is evaluated. Variations in the intensity of the raw ion current signal are compensated by the raw ion current signal or the value of the pinking intensity being standardized. The time pattern of the raw ion current signal assembles first from ignition disturbances, then from a first maximum of the combustion and then from a second maximum of the ion current.