Method and Device for Detecting Auto-ignitions in a Spark Ignition Internal Combustion Engine

An engine control unit for an internal combustion engine for identifying a spontaneous ignition in the internal combustion engine, the internal combustion engine including a plurality of cylinders and a crankshaft coupled to each cylinder, and the engine control unit comprising a processor and memory coupled thereto, the memory having stored therein at least one program executable by the processor for configuring the engine control unit to:

• measure successive segment time periods which are assigned to the individual cylinders and which are required by the crankshaft to pass through predefined angle ranges during working strokes of the cylinders,
• subsequently determine running irregularity values from the segment time periods,
• in a predefined load/engine speed range of the internal combustion engine, compare the running irregularity values of all of the cylinders with a predefined threshold value,
• identify a suspicion of spontaneous ignition for a first cylinder of the plurality of cylinders if the running irregularity value of a second cylinder which precedes the first cylinder in time in an ignition sequence falls below the predefined threshold value,
• interrupt a fuel supply to the first cylinder suspected of spontaneous ignition for a predefined number of cycles,
• detect an influence of the interruption of fuel to the first cylinder on the running irregularity values of the second cylinder during the cycles, and
• confirm or reject the suspicion of spontaneous ignition for the first cylinder depending on occurring running irregularity values of the second cylinder.