Engine diagnosis from frequency components in exhaust
First Claim
1. An engine diagnostic apparatus, comprising:
- transducer means for translating a pressure waveform emitted by an engine to a corresponding complex electrical signal having a prominent fundamental frequency component which varies in frequency in direct proportion with engine speed, and having a subharmonic frequency component at a frequency which is a submultiple of said fundamental frequency,separator means to separate said subharmonic frequency, components and said fundamental frequency component from said complex electrical signal and from each other, andcomparator means to compare the amplitude of said subharmonic frequency component with the amplitude of said fundamental frequency component to provide a measure of the unevenness of power strokes from individual cylinders of the engine.
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Abstract
An engine diagnostic apparatus includes a transducer for translating an exhaust pressure waveform emitted by an engine to a corresponding complex electrical signal having a prominent fundamental frequency component which represents the cylinder firing frequency and varies in direct proportion with engine speed, and having a subharmonic frequency component at a frequency which is a submultiple of the fundamental frequency. The subharmonic frequency component and the fundamental frequency component are separated from the complex electrical signal and from each other. A comparator compares the amplitude of the subharmonic frequency component with the amplitude of the fundamental frequency component to provide a measure of the unevenness of power strokes from individual cylinders of the engine.
8 Citations
8 Claims
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1. An engine diagnostic apparatus, comprising:
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transducer means for translating a pressure waveform emitted by an engine to a corresponding complex electrical signal having a prominent fundamental frequency component which varies in frequency in direct proportion with engine speed, and having a subharmonic frequency component at a frequency which is a submultiple of said fundamental frequency, separator means to separate said subharmonic frequency, components and said fundamental frequency component from said complex electrical signal and from each other, and comparator means to compare the amplitude of said subharmonic frequency component with the amplitude of said fundamental frequency component to provide a measure of the unevenness of power strokes from individual cylinders of the engine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification