Frequency domain engine defect signal analysis
First Claim
1. A signal analyzer for detecting engine defects including:
- an engine speed sensor means for detecting engine speed and generating an electrical engine speed signal;
an exhaust pressure sensor means for detecting engine exhaust pressure and generating an electrical exhaust pressure signal;
an intake manifold vacuum sensor means for detecting engine intake manifold vacuum and generating an electrical intake manifold vacuum signal;
a crankcase pressure sensor means for detecting blowby gas pressure in the engine crankcase and generating an electrical crankcase pressure signal;
an oil pressure sensor means for detecting engine oil pressure and generating an electrical oil pressure signal;
a frequency domain analyzer circuit means coupled to said engine speed sensor means exhaust pressure sensor means, intake manifold vacuum sensor means, crankcase pressure sensor means and oil pressure sensor means for generating a frequency domain spectrum signal from the outputs of said coupled sensor means; and
a comparison means coupled to said frequency domain analyzer circuit means for comparing said frequency domain spectrum signal to a normal engine signal thereby determining at what frequencies differences between the two signals exist, such differences being indicative of engine defects.
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Accused Products
Abstract
A signal analyzer for detecting engine defects includes sensors (11-17) for detecting engine operating parameters such as engine speed, engine exhaust manifold pressure, engine intake manifold vacuum, blowby gas pressure in the engine crankcase, and oil pressure. Electrical signals representing the frequency and magnitude of the engine operating parameters are used to produce a frequency domain spectrum signal characteristic of the engine being tested. The frequency domain spectrum signal being tested is compared to a frequency domain spectrum signal from a normal engine thereby determining at what frequencies differences between the two signals exist, such differences being indicative of engine defects.
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Citations
29 Claims
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1. A signal analyzer for detecting engine defects including:
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an engine speed sensor means for detecting engine speed and generating an electrical engine speed signal; an exhaust pressure sensor means for detecting engine exhaust pressure and generating an electrical exhaust pressure signal; an intake manifold vacuum sensor means for detecting engine intake manifold vacuum and generating an electrical intake manifold vacuum signal; a crankcase pressure sensor means for detecting blowby gas pressure in the engine crankcase and generating an electrical crankcase pressure signal; an oil pressure sensor means for detecting engine oil pressure and generating an electrical oil pressure signal; a frequency domain analyzer circuit means coupled to said engine speed sensor means exhaust pressure sensor means, intake manifold vacuum sensor means, crankcase pressure sensor means and oil pressure sensor means for generating a frequency domain spectrum signal from the outputs of said coupled sensor means; and a comparison means coupled to said frequency domain analyzer circuit means for comparing said frequency domain spectrum signal to a normal engine signal thereby determining at what frequencies differences between the two signals exist, such differences being indicative of engine defects. - View Dependent Claims (2)
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3. A signal analyzer for detecting engine defects including:
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a plurality of sensing means coupled to the engine for detecting at least two engine operating parameters from the following group;
engine speed, engine exhaust manifold pressure, intake manifold vacuum, crankcase gas pressure, and oil pressure;a frequency domain analyzer circuit means coupled to receive said at least two engine operating parameters for generating a frequency domain spectrum signal as a function of said at least two engine operating parameters; and a comparison means coupled to said frequency domain analyzer circuit means for comparing said frequency domain spectrum signal to a normal engine signal thereby determining at what frequencies differences between the two signals exist, such differences being indicative of particular types of engine defect depending upon the pattern of such differences. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A signal analyzer for detecting defects in a multi-cylinder engine including:
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a plurality of sensing means coupled to the engine for detecting engine operating parameters including engine exhaust manifold pressure, intake manifold vacuum, crankcase gas pressure and oil pressure; and a bandpass filter associated with at least one of said sensing means for passing a band of frequencies including the frequency of cylinder firings. - View Dependent Claims (28, 29)
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Specification