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Diagnosis of knock sensor: General Description

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The purpose of the diagnosis is to detect faults of the knock sensor. Therefore the signal range and dynamics of a low pass filtered knock signal is checked.

If the signal range exceeds a upper or lower threshold a failure is detected.

An implausible knock signal is detected by using a statistical analysis. The difference between filtered knock signal and raw knock signal is estimated for a certain number of combustion cycles.

All error symptoms are de-bounced.

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