Methods and systems to derive engine component health using total harmonic distortion in a knock sensor signal

A system comprising:

• a reciprocating device controller configured to control a reciprocating device, wherein the reciprocating device controller comprises a processor configured to:
• obtain one or more frequencies, wherein each of the one or more frequencies corresponds to the fundamental frequency of a reciprocating device component;
• receive a signal from a knock sensor coupled to a reciprocating device;
• derive total harmonic distortion (THD) at the one or more frequencies;
• and
• determine whether the derived THD exceeds a threshold value.

A non-transitory computer readable medium comprising executable instructions that when executed cause a processor to:

• obtain one or more frequencies, wherein each of the one or more frequencies corresponds to the fundamental frequency of a reciprocating device component;
• receive a signal from a knock sensor coupled to a reciprocating device;
• derive total harmonic distortion (THD) at the one or more frequencies;
• determine whether the derived THD exceeds a threshold value;
• and
• provide a user perceptible indication of the presence of distortion.