System and method for detecting operating events of an engine via MIDI

1. A method of monitoring an operating event of a combustion engine, comprising:

capturing, via baselining the combustion engine, the combustion engine's musical instrument digital interface (MIDI) fingerprint, wherein the MIDI fingerprint comprises a string of musical notes corresponding to engine noises made by the combustion engine during the baselining, and wherein each note comprises a pitch and a MIDI velocity corresponding to a representative noise of the engine noises;

receiving a noise signal sensed by a knock sensor disposed in or proximate to the combustion engine;

correlating the noise signal with the combustion engine's musical instrument digital interface (MIDI) fingerprint having at least an Attack Decay Sustain Release (ADSR) envelope indicative of the operating event of the combustion engine; and

detecting if the operating event has occurred based on the correlating of the noise signal with the fingerprint.

2. The method of claim 1 , wherein the operating event comprises an opening of an intake valve of the internal combustion engine, a closing of the intake valve, an opening of an exhaust valve of the internal combustion engine, a closing of the exhaust valve, or a peak firing pressure.

3. The method of claim 1 , wherein baselining the combustion engine to derive the combustion engine's MIDI fingerprint having at least the ADSR envelope comprises:

deriving the ADSR envelope from a baseline noise signal converted into a MIDI encoded baseline noise signal indicative of the operating event and applying a plot of the ADSR envelope and operating event indicator data against time to derive a location of the ADSR envelope at which the operating event occurs.

4. The method of claim 3 , comprising deriving the location of the ADSR envelope at which the operating event occurs by determining an intersecting point between the ADSR envelope and the operating event indicator data.

5. The method of claim 3 , wherein the location of the ADSR envelope at which the operating event occurs is approximately a midpoint of a decay vector of the ADSR envelope.

6. The method of claim 3 , wherein the location of the ADSR envelope at which the operating event occurs is within a mid-region of a decay vector of the ADSR envelope.

7. The method of claim 1 , wherein correlating the noise signal with the engine MIDI fingerprint comprises converting the noise signal to a MIDI data and then correlating the MIDI data to the engine's MIDI fingerprint, converting the engine's MIDI fingerprint to a vibration fingerprint and then correlating the noise signal to the vibration fingerprint.

8. The method of claim 1 , wherein correlating the noise signal with the MIDI fingerprint having at least the ADSR envelope indicative of the operating event comprises preconditioning the noise signal and superimposing the ADSR envelope onto at least a portion of a plot of the preconditioned noise signal.

9. The method of claim 1 , wherein correlating the noise signal with the engine's MIDI fingerprint having at least the ADSR envelope indicative of the operating event comprises applying a plot of the noise signal, or a preconditioned version of the noise signal, against a crank angle signal of a crankshaft of the combustion engine received from a crankshaft sensor and superimposing the ADSR envelope of the engine MIDI fingerprint onto at least a portion of the plot.

10. A system, comprising:

an engine controller configured to monitor a first operating event of a combustion engine, wherein the engine controller comprises a processor configured to:

store a first engine's musical instrument digital interface (MIDI) fingerprint that has been captured via baselining the combustion engine, wherein the MIDI fingerprint comprises a string of musical notes corresponding to engine noises made by the combustion engine during the baselining, and wherein each note comprises a pitch and a MIDI velocity corresponding to a representative noise of the engine noises;

receive a noise signal sensed by a knock sensor disposed in or proximate to the combustion engine;

correlate the noise signal with the first engine's musical instrument digital interface (MIDI) fingerprint having at least a first Attack Decay Sustain Release (ADSR) envelope indicative of the first operating event; and

detect if the first operating event has occurred based on the correlating of the noise signal with the first engine's MIDI fingerprint.

11. The system of claim 10 , wherein the controller comprises a memory configured to store one or more MIDI fingerprints, each MIDI fingerprint having a respective ADSR envelope indicative of a corresponding operating event, and wherein the processor is configured to access the memory to correlate the noise signal with the first engine MIDI fingerprint having at least the first ADSR envelope indicative of the first operating event.

12. The system of claim 10 , comprising the knock sensor configured to sense the noise signal and a crankshaft sensor configured to sense a crank angle of a crankshaft of the combustion engine, and wherein the processor is configured to correlate the noise signal with the first engine's MIDI fingerprint by converting the noise signal to a MIDI data and then correlate the MIDI data to the first engine's MIDI fingerprint, wherein the processor is configured to convert the MIDI fingerprint to a vibration fingerprint and then correlate the noise signal to the vibration fingerprint, or a combination thereof.

13. The system of claim 12 , wherein the processor is configured to apply a plot of the noise signal, or a preconditioned version of the noise signal, against the crank angle, and superimpose the first ADSR envelope over the noise signal or preconditioned noise version of the noise signal via the plot.

14. The system of claim 13 , wherein the processor is configured to derive a location on the superimposed first ADSR envelope at which the operating event occurs.

15. The system of claim 14 , wherein the processor is configured to determine a midpoint of a decay vector of the superimposed first ADSR envelope, wherein the location on the superimposed first ADSR envelope at which the operating event occurs is the midpoint.

16. The system of claim 10 , wherein the operating event comprises an opening of an intake valve of the combustion engine, a closing of the intake valve, an opening of an exhaust valve of the combustion engine, a closing of the exhaust valve, or a peak firing pressure.

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

retrieve a combustion engine's musical instrument digital interface (MIDI) fingerprint that has been captured via baselining the combustion engine;

receive, from a knock sensor disposed in or proximate to the combustion engine, noise data indicative of noise emitted by the combustion engine;

receive, from a crankshaft sensor disposed in or proximate to the combustion engine, crank angle data indicative of a crank angle of a crankshaft of the combustion engine;

derive a plot of the noise data against the crank angle data;

determine a portion of the noise data that corresponds to an engine's musical instrument digital interface (MIDI) fingerprint having a reference Attack Decay Sustain Release (ADSR) envelope indicative of an operating event of the combustion engine, wherein the MIDI fingerprint comprises a string of musical notes corresponding to engine noises made by the combustion engine during baselining, and wherein each note comprises a pitch and a MIDI velocity corresponding to a representative noise of the engine noises;

superimpose the reference ADSR envelope over the noise data via the plot; and

determine a location in the noise data at which the operating event occurred.

18. The non-transitory computer readable medium comprising executable instructions of claim 17 that, when executed, further cause the processor to:

determine a midpoint on a decay vector of the reference ADSR envelope, wherein the midpoint on the decay vector of the reference ADSR envelope corresponds to the location at which the operating event occurs.

19. The non-transitory computer readable medium comprising executable instructions of claim 17 that, when executed, further cause the processor to precondition the noise data before deriving the plot of the noise data.