Apparatus and method for processing engine measurements
First Claim
1. A method for processing measurements from an internal combustion engine having a rotatable crankshaft wherein each measurement corresponds to an angular position of the crankshaft, the method comprising:
- filtering the measurements to produce a series of filtered measurements wherein each filtered measurement represents a predetermined number of neighboring measurements so as to examine local variation among contiguous measurements;
combining filtered measurements which correspond to a particular angular position of the crankshaft to produce combined measurements having reduced random noise; and
subtracting one of a series of predetermined values each representing systematic activity at a particular angular position of the crankshaft from each corresponding combined filtered measurement to reduce systematic variation present within the measurements so as to produce a diagnostic envelope which allows both detection and identification of engine operating anomalies.
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Abstract
A diagnostic envelope is used to analyze measurements from an internal combustion engine. Measurements may be from a partially assembled engine during a cold test to detect subtle mechanical anomalies, or from a fully assembled engine during a cold test or a hot test (with active fuel and spark). The measurements represent vibrational amplitudes corresponding to various crankshaft angular positions of the internal combustion engine. The first step in generating the diagnostic envelope includes filtering the measurements to enhance local variations. Filtered measurements representing a number of engine cycles are then combined to reduce random cycle-to-cycle variations. The diagnostic envelope is then generated by subtracting corresponding measurements obtained from engines with known operating characteristics. The diagnostic envelope is used in analyzing and/or classifying the engine. A fuzzy logic classifier is used to detect subtle mechanical anomalies while principal component analysis is utilized in analyzing engine performance, detecting less subtle mechanical defects, and in designing and validating engines.
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Citations
30 Claims
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1. A method for processing measurements from an internal combustion engine having a rotatable crankshaft wherein each measurement corresponds to an angular position of the crankshaft, the method comprising:
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filtering the measurements to produce a series of filtered measurements wherein each filtered measurement represents a predetermined number of neighboring measurements so as to examine local variation among contiguous measurements; combining filtered measurements which correspond to a particular angular position of the crankshaft to produce combined measurements having reduced random noise; and subtracting one of a series of predetermined values each representing systematic activity at a particular angular position of the crankshaft from each corresponding combined filtered measurement to reduce systematic variation present within the measurements so as to produce a diagnostic envelope which allows both detection and identification of engine operating anomalies. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A system for processing measurements from an internal combustion engine having a rotatable crankshaft wherein each measurement corresponds to an angular position of the crankshaft, the system comprising:
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means for filtering the measurements to produce a series of filtered measurements wherein each filtered measurement represents a predetermined number of neighboring measurements so as to examine local variation among contiguous measurements; means for combining filtered measurements which correspond to a particular angular position of the crankshaft so as to reduce random noise within the measurements; and means for subtracting one of a series of predetermined values each representing systematic activity at a particular angular position of the crankshaft from each corresponding combined filtered measurement to reduce systematic variation present within the measurements so as to produce a diagnostic envelope indicative of engine condition. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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30. A system for processing measurements from an internal combustion engine having a rotatable crankshaft wherein each measurement corresponds to an angular position of the crankshaft, the system comprising:
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a motor coupled to the crankshaft for rotating the crankshaft; at least one sensor in contact with the internal combustion engine for generating a signal indicative of vibrational activity of the internal combustion engine; a position sensor for generating a signal indicative of an angular position of the crankshaft; a processor in communication with the at least one sensor and the position sensor for filtering the signals from the at least one sensor to produce a series of filtered signal values wherein each filtered signal value represents a predetermined number of neighboring signal values, the processor also being operative to combine the filtered signal values which correspond to a particular angular position of the crankshaft and to subtract one of a series of predetermined values, representing systematic vibrational activity at a particular angular position of the crankshaft, from each corresponding combined signal value so as to produce a diagnostic envelope which is indicative of engine condition.
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Specification