Misfire detection in an internal combustion engine
First Claim
1. A method for detecting misfires of cylinders of a reciprocating internal combustion engine, the method comprising the steps of:
- predefining an fueled acceleration profile for a normal operation of the engine;
acquiring a series of acceleration data representative of acceleration behavior of the reciprocating engine using a central difference algorithm;
sampling the data to obtain acceleration data samples at a rate sufficient to obtain up to fourth-order perturbations of the acceleration data;
correcting the samples using the fueled acceleration profile;
filtering the samples to provide bandwidth limited samples;
providing the samples to at least two channels;
pattern matching the samples in the first channel to enhance harmonic phenomena and reduce random phenomena;
pattern canceling the samples in the second channel to enhance random phenomena and reduce harmonic phenomena; and
detecting misfires dependent on a magnitude of the filtered acceleration data samples.
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Accused Products
Abstract
A method and system for a misfire detection acquires (301) a series of acceleration data (302) representative of acceleration behavior of an engine. The data is sampled (304) to obtain acceleration data samples at a rate sufficient to obtain up to fourth-order perturbations of the data. The samples are filtered (322) to provide bandwidth limited samples, which are provided to at least two channels (325, 329). The samples are pattern matched (332) in a first channel to enhance harmonic phenomena and pattern canceled (330) in a second channel to enhance random phenomena. Hard and random misfires are detected (334) dependent on a magnitude of the filtered acceleration data samples. Preferably, a third channel (335) is added to detect multiple misfires.
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Citations
22 Claims
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1. A method for detecting misfires of cylinders of a reciprocating internal combustion engine, the method comprising the steps of:
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predefining an fueled acceleration profile for a normal operation of the engine;
acquiring a series of acceleration data representative of acceleration behavior of the reciprocating engine using a central difference algorithm;
sampling the data to obtain acceleration data samples at a rate sufficient to obtain up to fourth-order perturbations of the acceleration data;
correcting the samples using the fueled acceleration profile;
filtering the samples to provide bandwidth limited samples;
providing the samples to at least two channels;
pattern matching the samples in the first channel to enhance harmonic phenomena and reduce random phenomena;
pattern canceling the samples in the second channel to enhance random phenomena and reduce harmonic phenomena; and
detecting misfires dependent on a magnitude of the filtered acceleration data samples. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for detecting misfires of cylinders of a reciprocating internal combustion engine, the method comprising the steps of:
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predefining a fueled acceleration profile for a normal operation of the engine and a non-fueled correction profile;
acquiring a series of acceleration data representative of acceleration behavior of the reciprocating engine using a central difference algorithm at each sample that takes a difference between an earlier velocity sample and a later velocity sample;
oversampling the data to obtain acceleration data samples at a rate sufficient to obtain up to fourth-order perturbations of the acceleration data;
adapting the fueled acceleration profile as a function of speed and load;
correcting the samples using the fueled correction profile and the non-fueled correction profile;
filtering the samples with a variable order finite-impulse response to provide bandwidth limited samples;
providing the sales to at least two channels;
highpass filtering the samples non-linearly in each channel;
pattern matching the samples in the first channel to enhance harmonic phenomena and reduces random phenomena for detecting hard misfires;
pattern canceling the samples in the second channel to enhance random phenomena and reduces harmonic phenomena for detecting random misfires; and
detecting misfires dependent on a magnitude of the filtered acceleration data samples. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A misfire detection system for a reciprocating internal combustion engine, the system comprising:
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acceleration measurement means for acquiring a series of acceleration data representative of acceleration behavior of the reciprocating engine using a central difference algorithm;
means for sampling the data to obtain acceleration data samples at a rate sufficient to obtain up to fourth-order perturbations of the acceleration data;
means for filtering the samples to provide bandwidth limited samples;
means for pattern matching the samples to enhance harmonic phenomena over random phenomena;
means for pattern canceling the samples in the second channel to enhance random phenomena over harmonic phenomena; and
means for detecting misfires dependent on a magnitude of the filtered acceleration data samples. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification