Prognostication of future failure of an engine indicator parameter

• US 6,285,947 B1
• Filed: 10/28/1999
• Issued: 09/04/2001
• Est. Priority Date: 10/28/1999
• Status: Expired due to Term

• Current Assignee: Woodward Governor Company
• Original Assignee: Brunswick Corporation
• Inventors: Lemancik, Michael J., Divljakovic, Vojislav
• Primary Examiner(s): WOLFE JR, WILLIS RAY
• Application Number:
  US09/428,690
• Time in Patent Office: 677 Days
• Field of Search: 123/406.24, 123/406.25, 123/406.27, 123/406.28, 123/406.26, 123/406.38, 123/406.33, 123/436, 701/102, 701/103, 701/110, 701/111, 701/115, 731/16, 731/173
• US Class Current: 701/110
• CPC Class Codes: B63B 79/10 using sensors, e.g. pressure sensors, strain gauges or accelerometers
• CPC Class Codes: B63B 79/30 for diagnosing, testing or predicting the integrity or performance of vessels
• CPC Class Codes: G05B 23/0235 based on a comparison with predetermined threshold or range, e.g. "classical methods", carried out during normal operation; threshold adaptation or choice; when or how to compare with the threshold
• CPC Class Codes: G05B 23/0283 Predictive maintenance, e.g. involving the monitoring of a system and, based on the monitoring results, taking decisions on the maintenance schedule of the monitored system; Estimating remaining useful life [RUL] preventive maintenance, i.e. planning maintenance according to the available resources without monitoring the system G06Q10/06

Abstract

Power spectral densities are taken at periodic intervals for preselected indicator parameters and these power spectral density profiles are compared to a reference magnitude of a power spectral density profile for purposes of prognosticated future failures. The power spectral density profile can be for any one of a plurality of indicator profiles, such as an accelerometer output, the output of a pressure sensor, or a voltage output from an ignition system.

Claims

1. Apparatus for prognosticating a condition of a marine propulsion system, comprising:

means for determining a reference magnitude of an indicator parameter under a first set of preselected operating conditions;

means, connected in signal communication with said determining means, for storing said reference magnitude of an indicator parameter;

means for measuring a current magnitude of said indicator parameter under said first set of preselected operating conditions, said current magnitude being measured subsequent to said reference magnitude being determined;

means, connected in signal communication with said storing means, for comparing said reference and current magnitudes; and

means, connected in signal communication with said comparing means, for detecting a change in said condition of said marine propulsion system.

2. A method for prognosticating a condition of a apparatus, comprising:

determining a reference magnitude of an indicator parameter under a first set of preselected operating conditions, said apparatus being a marine propulsion system;

storing said reference magnitude of an indicator parameter;

measuring a current magnitude of said indicator parameter under said first set of preselected operating conditions, said current magnitude being measured subsequent to said reference magnitude being determined;

comparing said reference and current magnitudes; and

detecting a change in said condition of said apparatus as a function of said comparing step.

3. The method of claim 2, further comprising:

repeating said measuring, comparing, and detecting steps at a predetermined frequency.

4. The method of claim 2, further comprising:

determining said reference magnitude of each of a plurality of indicator parameters under an associated first set of preselected operating conditions for each of said plurality of indicator parameters;

storing said reference magnitude of each of said plurality of indicator parameters;

measuring said current magnitude of each of said plurality of indicator parameters under said associated first set of preselected operating conditions, said current magnitude of each of said plurality of indicator parameters being measured subsequent to said reference magnitude of each of said plurality of indicator parameters being determined;

comparing each of said reference magnitudes to its associated current magnitude; and

detecting a change in said condition of said apparatus as a function of said comparing step.

5. The method of claim 2, wherein:

said indicator parameter is an output from an accelerometer.

6. The method of claim 2, wherein:

said indicator parameter is an output from a fuel pressure sensor.

7. The method of claim 2, wherein:

said indicator parameter is an output from an ignition system.

8. The method of claim 2, wherein:

said indicator parameter is an output from an air pressure sensor.

9. The method of claim 2 wherein:

said marine propulsion system comprises a gear case, a fuel supply system, an ignition system, an oil delivery system, and an air delivery system.

10. The method of claim 2, wherein:

said indicator parameter is a power spectral density of a preselected variable.

11. The method of claim 2, wherein:

said indicator parameter is a plurality of values representing power spectral density of a preselected variable for a plurality of frequencies.

12. The method of claim 2, wherein:

said indicator parameter is the integral of a power spectral density of a preselected variable.

13. The method of claim 2, wherein:

said first set of preselected operating conditions comprise a magnitude of the speed of an engine and a magnitude of a load on said engine.

14. A method for prognosticating a condition of a apparatus, comprising:

determining a reference magnitude of each of a plurality of indicator parameters under an associated first set of preselected operating conditions for each of said plurality of indicator parameters;

storing said reference magnitude of each of said plurality of indicator parameters;

measuring a current magnitude of each of said plurality of indicator parameters under said associated first set of preselected operating conditions, said current magnitude of each of said plurality of indicator parameters being measured subsequent to said reference magnitude of each of said plurality of indicator parameters being determined;

comparing each of said reference magnitudes to its associated current magnitude;

detecting a change in said condition of said apparatus as a function of said comparing step; and

repeating said measuring, comparing, and detecting steps at a predetermined frequency.

15. The method of claim 14, wherein:

said apparatus is a marine propulsion system which comprises a gear case.

16. The method of claim 14, wherein:

said indicator parameter is a power spectral density of a preselected variable.

17. The method of claim 14, wherein:

said indicator parameter is a plurality of values representing power spectral density of a preselected variable for a plurality of frequencies.

18. The method of claim 14, wherein:

said indicator parameter is the integral of a power spectral density of a preselected variable.

19. The method of claim 14, wherein:

said first set of preselected operating conditions comprise a magnitude of the speed of an engine and a magnitude of a load on said engine.