Control of detonation

Control of detonation

This strategy has the task of detecting the presence of detonation by processing the signal coming from the appropriate sensor. The strategy continuously compares the signal coming from the sensor with a threshold value which is, in turn, constantly updated to take into account background noise and the age-ing of the engine.

If the system recognizes the presence of detonation, the strategy reduces the ignition advance, in steps of 2°, up to a maximum of 7°, until the phenomenon disappears. Later, the advance is gradually restored to the basic value or until the onset of the phenomenon. In particular, the increases in the advance are im-plemented gradually, whilst the decreases are implemented immediately.

In acceleration conditions, the strategy uses a higher threshold to take into account the increased engine noise under these circumstances.

The strategy is also equipped with a self-adaptation function which temporarily memorizes the reductions in the advance which are continuously repeated in order to adjust the advance to the different conditions in which the engine finds itself (for example, the use of a low octane rating fuel). The strategy is capable of restoring the advance to the map value if the conditions which caused the reduction no longer exist.