Engine generated waveform analyzer

• US 4,394,742 A
• Filed: 10/31/1980
• Issued: 07/19/1983
• Est. Priority Date: 10/31/1980
• Status: Expired due to Term

• Current Assignee: Snap-On Technologies Incorporated (Snap-On Incorporated)
• Original Assignee: FMC Corporation
• Inventors: Gold, Kenneth S., Pelta, Edmond R., Vandermeyden, Tom R., Johnson, David G., Crummer, Marvin R.
• Primary Examiner(s): Wise, Edward J.
• Application Number:
  US06/202,516
• Time in Patent Office: 991 Days
• Field of Search: 364/580, 364/487, 364/424, 364/431.04, 73/117.3, 73/117.2, 324/379-380, 324/383-384, 324/393
• US Class Current: 701/102
• CPC Class Codes: F02P 17/08 using a cathode-ray oscilloscope F02P17/06 takes precedence

Abstract

An internal combustion engine analyzer provides both data acquisition and data processing and includes an analog waveform analysis subsystem together with a general purpose background system wherein appropriate power distribution is provided for the system as a whole and peripheral equipment such as a printer, keyboard and an analog/digital CRT is also provided. The input signals to be analyzed are waveforms generally associated with internal combustion engines and peripheral equipment. Exemplary waveforms are the primary and secondary ignition waveforms. The waveforms are attenuated to reasonable levels and multiplexed to analog circuitry which serves to measure waveform magnitude at one or more sampling points along the length of the wave and to also measure the manner in which the characteristics of the waveform change. The analog measurements are digitized and coupled to a processor which in turn controls the operation of the analog circuitry. The digitized measurements together with previously entered engine identification data are analyzed by the processor to thereby control subsequent data taking and to generate appropriate maintenance and repair instructions which are communicated visually to an operator in the disclosed embodiment.

Claims

1. An internal combustion engine wave characteristic analyzer for a two dimensional wave signal representative of an operating characteristic of the engine wherein predetermined wave characteristic data are held in storage, comprising means for receiving the wave signal and for providing a plurality of sampled output signals corresponding to wave characteristics at a plurality of positions along the length of the wave, means for receiving and storing data indicative of said plurality of output signals, means for continuously performing analysis of ones of said plurality of output signal data utilizing others of said plurality of output signal data and ones of said predetermined wave characteristic data, thereby providing a discrete analysis signal, means for continuously receiving and diagnosing the engine operating characteristic in view of said discrete analysis signal and for providing a diagnostic signal for the engine operating characteristic responsive thereto, means coupled to said diagnostic signal for providing an instruction output relating to operations required to retain and reestablish the predetermined wave characteristic, and means for alphanumerically displaying said instruction output.

2. A wave characteristic analyzer as in claim 1 wherein said means for receiving the wave signal comprises analog circuitry including means for processing sampled analog wave signals.

3. A wave characteristic analyzer as in claim 1 wherein said means for continuously performing analysis comprises a processor in communication with said means for receiving and storing.

4. An engine analyzer for determining characteristics of a two dimensional wave signal associated with an internal combustion engine, comprising means for sampling a plurality of the wave signals at a controlled sample point on the wave signals and for providing a signal amplitude measurement at the sample point along the length of the wave, means for storing an indication of each of said amplitude measurements, means for processing ones of said signal amplitude measurements to obtain at least one reference indication, means for comparing ones of said stored indications with said reference indication, thereby providing a comparison signal, a processor connected to receive said comparison signal, said processor being coupled to a diagnosis storage, means for fetching analysis information from a predetermined location in said diagnosis storage corresponding to said comparison signal, said analysis information including instructions for altering the wave characteristics to obtain predetermined wave characteristics, and means for displaying said instructions.

5. An engine analyzer as in claim 4 wherein said means for sampling comprises a threshold detection circuit for determining the position along the length of the ignition wave where predetermined signal levels are crossed.

6. An engine analyzer as in claim 5 wherein said threshold detection circuit comprises means for changing threshold sensitivity, said last named means being programmable by said processor.

7. An engine analyzer as in claim 4 wherein the two dimensional wave signal is an engine ignition wave obtained from a conventional points, capacitor and coil type ignition, and wherein said means for sampling comprises a threshold detector for sensing when the ignition points close and open and for providing a binary signal having one state when points are closed and another state when points are open, and means for averaging the binary signal, whereby a signal corresponding to points dwell is obtained.

8. An engine analyzer as in claim 4 wherein said means for sampling comprises an analog signal conditioning circuit for receiving the waveform, said processor providing a command signal coupled to said signal conditioning circuit, said command signal operating to control the position of the sample point.

9. An engine analyzer as in claim 8 wherein said means for sampling is commanded by said processor to obtain additional amplitude measurements from each of the waveforms, said processor operating to control the position of said additional amplitude measurements in accordance with said command signal.

10. A wave characteristic analyzer for periodic waveforms generated by and representative of operating characteristics of an internal combustion engine and peripheral equipment associated therewith, comprising means for receiving each wave signal and for providing first and second sampled output signals corresponding to the wave characteristics at first and second sample points respectively along the length of the wave, means for receiving and storing data indicative of said first and second sampled output signals, means for comparing said stored data obtained from successive ones of said periodic waveforms and relating to said sampled output signals thereby providing an analysis signal, a processor for receiving and diagnosing the operating characteristics in accordance with said analysis signal and for providing a diagnostic signal related thereto, said processor further operating to select said first and second sample points.

11. A wave characteristic analyzer as in claim 10 wherein said means for receiving each wave signal comprises an analog circuit.

12. A wave characteristic analyzer as in claim 11 wherein said analog circuit includes a threshold detector circuit.

13. A wave characteristic analyzer as in claim 11 wherein said analog circuit includes a waveform peak detection circuit.

14. A wave characteristic analyzer as in claim 10 wherein the waveform has predetermined desired characteristics, together with means coupled to receive said diagnostic signal for providing an instruction output relating to operations required to retain and reestablish the predetermined wave characteristics, and means for displaying said instruction output.

15. An analyzer for use by an operator in determining deviations from normal characteristics of a two dimensional waveform signal produced by a machine wherein the waveform signal has a substantially predetermined shape for normal operation of the machine, comprising means for receiving and for conditioning the waveform signal, means coupled to said means for receiving for sampling said conditioned waveform signal, for providing data signals corresponding to said waveform samples, for continuously processing said data signals, for continuously controlling said means for receiving and conditioning, and for continuously diagnosing deviation of said data signals from the normal waveform characteristics utilizing others of said data signals, means coupled to said means for diagnosing for providing instructions for machine repairs to maintain and reestablish normal waveform characteristics, and means for communicating said instructions to the operator.

16. An analyzer as in claim 15 wherein said means for receiving comprises an analog circuit, and wherein said means coupled to said means for receiving includes means for digitizing said data signals and providing digitized data.

17. An analyzer as in claim 15 wherein said machine is an internal combustion engine having an ignition system including points, condensor and coil, and wherein the waveform signal is an engine ignition waveform, said data signal comprising an analog signal obtained when the points are closed, whereby points resistance is measured and said instructions relate to replacement and repair of the ignition points.

18. An analyzer as in claim 15 wherein said machine is an internal combustion engine having an ignition system including points, condensor and coil and wherein said data signals are peak kilovolt signals, said means for providing instructions providing instruction for replacement and repair of the coil, ignition conductors and condensor.

19. An analyzer as in claim 15 wherein the machine is an internal combustion engine having ignition points, wherein said means for sampling provides said data signals when the points are in the process of opening, thereby providing a points arcing signal, said means for providing instructions for machine repair referring to replacement and repair of ignition points.

20. An analyzer as in claim 15 wherein the machine is an internal combustion engine having ignition points, wherein said data signals are indicative of points dwell, together with an averaging circuit coupled to receive said data signals, said means for providing instructions for machine repair referring to replacement and repair of ignition points.

21. An analyzer for use by an operator in determining deviation from normal characteristics of an internal combustion engine ignition waveform wherein the engine ignition system includes ignition points, coil and spark plugs and the engine specifications are entered into a memory, comprising

means for sampling the ignition waveform in accordance with a selected diagnosis, thereby providing a sampled signal,

means for conditioning said sampled signal providing a data signal,

means for digitizing said data signal providing digitized data,

a data memory connected to store and digitized data,

means for continuously processing said digitized data, for continuously controlling said means for sampling, conditioning and digitizing, and for continuously diagnosing the deviation of said data from characteristics corresponding to normal waveform characteristics with reference to the stored engine specifications and said store digitized data,

means coupled to said means for diagnosing for providing instructions for repairs to maintain and reestablish normal waveform characteristics,

and means for communicating said instructions for maintenance and repair to the operator.

22. An analyzer as in claim 21 wherein said means for sampling and conditioning are analog circuits.

23. An analyzer as in claim 21 wherein an engine speed synchronizing signal is provided and wherein said means for continuously processing, controlling and diagnosing is sychronized with engine speed.

24. An analyzer as in claim 21 wherein said waveform signal is sampled throughout ignition point closure, whereby said instructions relate to maintenance and repair of the ignition points.

25. An analyzer as in claim 21 wherein said waveform signal is sampled during peak firing voltage, whereby said instructions relate to maintenance and repair of the coil and spark plugs.

26. An analyzer as in claim 21 wherein said waveform signal is sampled during ignition point dwell whereby said instructions relate to maintenance and repair of ignition points.

27. An analyzer as in claim 21 wherein said waveform signal is sampled at the termination of ignition point dwell, whereby said instructions relate to maintenance and repair of ignition points.

28. An analyzer for determining deviation from normal characteristics of an ignition waveform produced by an internal combustion engine ignition system, wherein the ignition system contains ignition points, distributor, coil, condensor, spark plugs and ignition system conductors, and wherein engine identification code is entered into a memory, comprising

a first electrical circuit coupled to receive the ignition waveform and providing a peak signal indicative of the maximum ignition system firing voltage,

a second electrical circuit coupled to receive said peak signal and the ignition waveform providing a digitized data signal,

a digitized data signal store,

a third electrical circuit coupled to receive the ignition waveform and providing an output indicative of passage of the ignition waveform through a predetermined threshold level,

a processor connected to receive said digitized data and theshold output operating to continuously control said first, second and third electrical circuits so that preselected cylinder waveforms are coupled thereto and preselected threshold levels are set therein,

said processor further operating to scrutinize said digitized data and threshold output with reference to store digitized data and the engine identification code and to thereby provide an instruction output for maintenance and repair of the engine ignition system,

and means for communicating said instruction output to an analyzer operator.

29. An analyzer as in claim 28 together with an averaging circuit coupled to receive said threshold output whereby a points dwell signal is provided.