Methods and apparatus for engine analysis using internal electrical signals
First Claim
1. A method of analyzing an engine for misfire activity, comprising:
- receiving an electrical signal corresponding to a plurality of cycles of the engine;
identifying energy spikes in the electrical signal corresponding to cylinder firings in the engine;
generating engine speed estimates based on spacing between the energy spikes; and
analyzing anomalies in the engine speed estimates to identify misfire activity in the engine;
wherein the energy spikes correspond to spark plug firings in the engine.
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Abstract
A method of analyzing an engine for misfire activity includes receiving an electrical signal associated with a plurality of cycles of the engine, identifying energy spikes in the electrical signal associated with cylinder firings in the engine, generating engine speed estimates based on spacing between the energy spikes, and analyzing anomalies in the engine speed estimates to identify misfire activity in the engine. Also described is a method of analyzing an engine for misfire activity including receiving an electrical signal associated with the engine, detecting AC ripple in the electrical signal, generating engine speed estimates in response to the detected AC ripple, and analyzing anomalies in the engine speed estimates to identify misfire activity in the engine.
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Citations
23 Claims
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1. A method of analyzing an engine for misfire activity, comprising:
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receiving an electrical signal corresponding to a plurality of cycles of the engine; identifying energy spikes in the electrical signal corresponding to cylinder firings in the engine; generating engine speed estimates based on spacing between the energy spikes; and analyzing anomalies in the engine speed estimates to identify misfire activity in the engine; wherein the energy spikes correspond to spark plug firings in the engine. - View Dependent Claims (2, 3, 4, 5)
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6. A method of analyzing an engine for misfire activity, comprising:
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receiving an electrical signal corresponding to a plurality of cycles of the engine; identifying components of the electrical signal corresponding to alternator poles in the engine wherein identifying components of the electrical signal associated with alternator poles comprises performing a fast Fourier transform of the electrical signal to identify a frequency of diode ripple harmonic energy; filtering the electrical signal with a bandpass filter around the identified frequency to provide a filtered electrical signal; normalizing an amplitude of the filtered electrical signal; tracking a peak of the filtered electrical signal; generating engine speed estimates in response to the peak of the filtered electrical signal; and analyzing anomalies in the engine speed estimates to identify misfire activity in the engine. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of analyzing an engine for misfire activity, comprising:
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receiving an electrical signal associated with the engine; detecting AC ripple in the electrical signal; generating engine speed estimates in response to the detected AC ripple; and analyzing anomalies in the engine speed estimates to identify misfire activity in the engine; wherein detecting the AC ripple in the electrical signal comprises performing a fast fourier transform of a sample of the electrical signal less than 20 ms long and identifying peaks in a spectrum of a bandpass signal of the electrical signal at a frequency between 700 Hz and 4000 Hz; the method further comprising removing amplitude variations from the sample of the electrical signal by forming an envelope between peaks in the bandpass electrical signal and normalizing the electrical signal with respect to the envelope. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification