Compression testing apparatus
First Claim
1. A Apparatus for testing the compression of an internal combustion engine including a first chamber, a second chamber, a first member movable inside the first chamber in order to compress gas within the first chamber during a first time period, a second member movable inside the second chamber in order to compress gas within the second chamber during a second time period, a starter motor for moving the first and second members during a starting period and an electrical system for supplying an electrical power signal to rotate the starter motor during the starting period, and apparatus comprising:
- converting means for generating a first group of discrete digital amplitude signals having values proportional to the amplitude of the electrical power signal at a plurality of discrete times during the first time period and for generating a second group of discrete digital amplitude signals having values proportional to the amplitude of the electrical power signal at a plurality of discrete times during the second time period;
processing means for selecting from the first group of discrete digital amplitude signals a first representative signal for representing the compression of the first chamber, for selecting from the second group of discrete digital signals a second representative signal for representing the compression of the second chamber and for generating relative compression digital signal having a value depending on the relative values of the first and second representative signals; and
display means for displaying the value of the relative compression digital signal.
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Accused Products
Abstract
The disclosure describes apparatus for determining the relative compression of the chambers of an internal combustion engine by analyzing the voltage or current waveform of the starter system during cranking. The waveform is rapidly and repetitively sampled by an analog-to-digital converter which converts the amplitude waveform into corresponding digital signals. A processor selects one of the signals having either a maximum or minimum value to represent each of the chambers. The processor automatically determines the number of chambers in the engine, determines the relative compression of the chambers and displays the result to the operator of the system.
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Citations
34 Claims
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1. A Apparatus for testing the compression of an internal combustion engine including a first chamber, a second chamber, a first member movable inside the first chamber in order to compress gas within the first chamber during a first time period, a second member movable inside the second chamber in order to compress gas within the second chamber during a second time period, a starter motor for moving the first and second members during a starting period and an electrical system for supplying an electrical power signal to rotate the starter motor during the starting period, and apparatus comprising:
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converting means for generating a first group of discrete digital amplitude signals having values proportional to the amplitude of the electrical power signal at a plurality of discrete times during the first time period and for generating a second group of discrete digital amplitude signals having values proportional to the amplitude of the electrical power signal at a plurality of discrete times during the second time period; processing means for selecting from the first group of discrete digital amplitude signals a first representative signal for representing the compression of the first chamber, for selecting from the second group of discrete digital signals a second representative signal for representing the compression of the second chamber and for generating relative compression digital signal having a value depending on the relative values of the first and second representative signals; and display means for displaying the value of the relative compression digital signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. Apparatus for testing the compression of an internal combustion engine including a plurality of N chambers, members movable within the chambers in order to compress gas within the chambers during N different time periods, a starter motor for moving the members inside the chambers during a starting period and an electrical system for supplying an electrical power signal to rotate the starter motor during the starting period, said apparatus comprising:
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converting means for generating N groups of discrete digital amplitude signals having values proportional to the amplitude of the electrical power signal at a plurality of discrete times during the N time periods; processor means for selecting from the N groups of discrete digital amplitude signals N representative signals A1 through AN respectively representing the compression of the N chambers and for calculating a relative compression digital signal R according to the equation;
##EQU2## where Q is a constant. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. Apparatus, for automatically determining the number of chambers in an internal combustion engine in which ignition signals are used to sequentially ignite fuel-air mixtures in the chambers, said apparatus comprising:
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means for generating a synchronizing signal in response to each ignition signal used to ignite the fuel-air mixture in a first one of the chambers; counting means for counting a synchronizing signal and each ignition signal occurring between two successive synchronizing signals; memory means for storing digital data; and processing means for transferring the contents of the counting means to the memory means after the number of chambers has been counted. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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Specification