Parameter controlled speed determination in internal combustion engine diagnostics

• US 4,064,746 A
• Filed: 05/07/1976
• Issued: 12/27/1977
• Est. Priority Date: 05/07/1976
• Status: Expired due to Term

• Current Assignee: Clean Air Technologies Inc.
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Armstrong, Lee R., Mercik, Henry J. Jr.
• Primary Examiner(s): Queisser, Richard C.
• Assistant Examiner(s): Ciarlante, Anthony V.
• Application Number:
  US05/684,039
• Time in Patent Office: 599 Days
• Field of Search: 73/116, 73/117.3, 73/118, 73/119, 73/168, 324/16 R, 324/161, 235/150.2, 235/150.3, 116/114 AE
• US Class Current: 73/114.57
• CPC Class Codes: G01M 15/09 by monitoring pressure in fluid ducts, e.g. in lubrication or cooling parts

Abstract

A parameter, such as oil pressure, is repetitively sampled along with indications of speed, such as clock counts from a flywheel tooth counter, the parameter value and speed indications being stored and retained through at least several samplings, the parameter samplings being analyzed to find one of interest, the related speed indication thereupon being converted into speed dimensions for use. Specifically, oil pressure and engine speed indications are simultaneously sampled and stored, being retained for several sampling intervals, successive pressure readings are compared to find the knee in the curve of oil pressure as the pressure regulator begins to cut in, the pressure ultimately determined to be at the knee and the related speed indication being brought out for use, with conversion of the speed indication to rpm dimensions.

Claims

1. In the method of testing the oil system of an internal combustion engine, the steps of:

accelerating an engine while loaded only with its own inertia, drag and accessory loads;

measuring a rate of change of pressure as the engine accelerates;

determining a decreasing slope in said rate; and

determining the oil pressure and the engine speed at the determined point of decreasing slope.

2. The method according to claim 1 wherein the rate of change of oil pressure with respect to time is monitored as the engine accelerates, and a decrease in the rate is taken as the determined point of decreasing slope.

3. The method according to claim 2 wherein the rate of change of oil pressure is determined by sampling the oil pressure in equal time intervals and subtracting each sample from a succeeding sample.

4. Apparatus for testing the oil pressure system in an internal combustion engine as the engine accelerates while loaded only by its own inertia, drag and accessory loading, comprising:

pressure sensing means adapted to be disposed to sense the pressure of the lubricating oil in the engine and provide a pressure signal indicative thereof;

speed sensing means adapted to be disposed to sense the rotation of the engine and to provide a speed signal indicative of the speed thereof; and

processing apparatus comprising means for sampling said pressure signal and providing pressure manifestations indicative of the pressure represented thereby a number of times during a time interval while the engine is accelerating and for determining the pressure at which the rate of oil pressure rise with speed begins to decrease.

5. Apparatus according to claim 4 wherein said processing apparatus also comprises means for determining the speed at which the rate of oil pressure rise begins to decrease.

6. Apparatus according to claim 4 wherein said processing apparatus comprises means for sampling the rise in pressure as a function of time and for determining the pressure at which the rise in pressure with respect to time begins to decrease.

7. The method of providing an indication, in speed dimensions, of the speed at which an engine parameter other than speed has a particular relationship, by sampling an indication of engine speed in non-speed dimensions contemporaneously with sampling of the other parameter, repetitively, processing the other parameter through sufficient samplings thereof to determine the desired relationship while saving the indications of speed in non-speed dimensions, and when the desired relationship has been determined, converting to speed dimensions only the particular speed indication relating to the parameter determined to have the proper relationship.

8. In the method of diagnosing an internal combustion engine, the steps of:

simultaneously sampling indications of speed in non-speed dimensions and indications of another parameter, repetitively, over a sufficient number of samplings so as to show a trend in the values of said other parameters being sampled;

determining, from the trend, a parameter value of interest; and

converting to speed dimensions the speed indication samples simultaneously with the parameter value of interest.

9. Apparatus for diagnosing an internal combustion engine, comprising:

a transducer adapted to be disposed with respect to the engine to sense a particular parameter, said parameter having a characteristic profile with a point of interest thereon which can be determined by analysis of several samples of said parameter including said point of interest;

speed sensing means, adapted to be disposed for response to mechanical movement of a portion of the engine in relationship to the angular revolutions of the engine, for providing successive measured data manifestations of the time elapsed during angular revolution of the engine through a known angle and therefore indicative of the speed of the engine as the engine rotates; and

processing apparatus including means for repetitively taking samples of said transducer and of said measured data manifestations and for storing said measured data mainfestations for at least the interval of said several samples, for analyzing successive samples derived from said transducer and determining a sample of interest and for converting the one of said measured data manifestations relating to said sample of interest into a manifestation of speed expressed in speed dimensions.