Engine analyzer with digital waveform display
First Claim
Patent Images
1. A test system for testing operation of a selected system or component of a multicylinder internal combustion engine, the test system comprising:
- means for providing a periodic analog electrical input waveform representative of operation of the selected system or component of the internal combustion engine under a test condition, the analog input waveform having a period which varies with engine speed;
analog-to-digital (A/D) converter means for sampling the analog input waveform periodically and converting each sample to a digital sample value which represents magnitude of the waveform at a time when the sample was taken;
data memory means for storing the digital sample values;
means for selecting a test to be performed;
means for maintaining a cylinder count based upon a signal derived from the engine;
means for supplying a signal to the A/D converter means to initiate sampling of the analog input waveform by the A/D converter means as a function of the test selected and the cylinder count;
means for transferring a predetermined number of the digital sample values representative of the input waveform from the A/D converter means to selected locations in the data memory means based upon the test selected;
means for selecting a display mode;
means for converting stored digital sample values to display data based upon the display mode selected; and
display means for displaying a simulated analog visual representation of the magnitude of the input waveform as a function of time based upon the display data.
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Abstract
An engine analyzer for an internal combustion engine includes an analog-to-digital (A/D) converter which digitizes an analog electrical input waveform representing, for example, a secondary or primary voltage waveform of the ignition coil of the internal combustion engine. The digitized input waveform is stored in the form of digital data in a data memory. Upon request by the operator of the apparatus, a microprocessor selects digital data stored, and supplies that digital data to a display, which displays a visual representation of the waveform based upon the selected digital data.
54 Citations
22 Claims
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1. A test system for testing operation of a selected system or component of a multicylinder internal combustion engine, the test system comprising:
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means for providing a periodic analog electrical input waveform representative of operation of the selected system or component of the internal combustion engine under a test condition, the analog input waveform having a period which varies with engine speed; analog-to-digital (A/D) converter means for sampling the analog input waveform periodically and converting each sample to a digital sample value which represents magnitude of the waveform at a time when the sample was taken; data memory means for storing the digital sample values; means for selecting a test to be performed; means for maintaining a cylinder count based upon a signal derived from the engine; means for supplying a signal to the A/D converter means to initiate sampling of the analog input waveform by the A/D converter means as a function of the test selected and the cylinder count; means for transferring a predetermined number of the digital sample values representative of the input waveform from the A/D converter means to selected locations in the data memory means based upon the test selected; means for selecting a display mode; means for converting stored digital sample values to display data based upon the display mode selected; and display means for displaying a simulated analog visual representation of the magnitude of the input waveform as a function of time based upon the display data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A test system for testing operation of a selected system or component of a multicylinder internal combustion engine, the test system comprising:
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means for providing a plurality of periodic analog waveform signals representative of operation of systems or components of the internal combustion engine, the analog waveform signals having periods which vary as a function of engine speed; input means for providing an input signal selecting a test to be performed; means for providing a count representing a currently operating cylinder of the engine; digitizing means for digitizing a selected analog input signal during a time interval based upon the input signal and the count to produce a plurality of digital sample values representing magnitude of the selected signal as a function of time; data memory means for storing the digital sample values in selected memory locations based upon the input signal; display control means for providing display data based upon the digital sample values; and display means for displaying a simulated analog visual representation of magnitude of a waveform as a function of time based upon the display data from the control means, the simulated analog visual representation being representative of a selected system or component of the internal combustion engine under the test condition. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A test system for testing operation of an ignition system of a multicylinder internal combustion engine, the test system comprising:
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primary waveform circuit means for deriving from the ignition system a primary analog input waveform for each cylinder of the engine; secondary waveform circuit means for deriving from the ignition system a secondary analog input waveform for each cylinder of the engine; means for selecting a test which requires at least one of the primary and secondary waveforms; means for maintaining a count representing the cylinder which corresponds to the waveforms being currently derived; means for providing a sample enable signal based upon the selected test and the count; analog-to-digital (A/D) converter means responsive to the sample enable signal for sampling the selected analog input waveform periodically and converting each sample to a digital sample value; data memory means for storing the digital sample values in locations determined by the selected test; display control means for providing display data based upon the stored digital sample values; and display means for displaying a simulated analog visual representation of magnitude of a waveform as a function of time based upon the display data. - View Dependent Claims (19, 20, 21, 22)
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Specification