Waveform count of teeth on an internal combustion engine flywheel

• US 4,055,998 A
• Filed: 12/06/1976
• Issued: 11/01/1977
• Est. Priority Date: 12/06/1976
• Status: Expired due to Term

• Current Assignee: Clean Air Technologies Inc.
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Pettingell, James R., Armstrong, Lee R.
• Primary Examiner(s): Myracle, Jerry W.
• Application Number:
  US05/747,755
• Time in Patent Office: 330 Days
• Field of Search: 73/118, 73/116, 73/117.2, 73/117.3, 73/517 R, 73/517 A, 73/119 R
• US Class Current: 73/114.77
• CPC Class Codes: G01M 13/021 Gearings

Abstract

The tooth-to-tooth time interval of teeth on a flywheel of a rotating internal combustion engine is recorded for at least a significant portion of an engine revolution, the variation in the time intervals are utilized to determine minima in the tooth-to-tooth time intervals, thereby to separate the tooth-to-tooth time intervals to cylinder-by-cylinder groupings. The number of teeth from one minima to the next for a given number of cylinders is summed. The summation of the number of teeth may then be used as a measured count of the number of teeth on the flywheel of the engine; this measured count may be compared against industry standards if desired. In a second embodiment, the measured count is averaged on a per-cylinder basis, and the tooth count for each cylinder is compared therewith and any data more than 20% off the average is eliminated from final computation of an average number of teeth for a given number of cylinders. The invention provides alternative use of engine cycle identification signals or engine tooth waveform analysis to measure the number of teeth on the flywheel.

Claims

1. Apparatus for determining the number of indicia on a member of an internal combustion engine directly connected to and rotating with the crankshaft of the engine, comprising:

sensing means adapted to be disposed to sense the passage of each of the indicia of the engine member when the engine is rotating, said means providing a sense signal each time that an indicium of the member passes in proximity to said sensing means; and

processing means responsive to the sense signals presented by said sensing means to generate manifestatins indicative of the time intervals between said sensing means sensing successive indicia over a time period which is at least a significant portion of one revolution of the engine, and responsive to the variations in said time intervals to identify the number of indicia sensed across an integral number of cylinder-related subcycles of an engine cycle and for generating a data manifestation indicative of the total number of said indicia on said member and available to be sensed in a complete revolution of said engine.

2. Apparatus according to claim 1 in which the member is a flywheel and the indicia are teeth on the flywheel and wherein:

said sensing means is a tooth proximity sensor issuing a tooth signal as said sense signal.

3. Apparatus for determining the number of teeth on the flywheel of an internal combustion engine comprising:

tooth sensing means adapted to be disposed to sense the passage of each tooth of the flywheel of an internal combustion engine when the engine is rotating, said means providing a tooth signal each time that a tooth of the flywheel passes in proximity to said tooth sensing means;

processing means responsive to the tooth signals presented by said tooth sensing means to generate manifestations indicative of the time intervals between said tooth sensing means sensing successive teeth over a time period which is at least a significant portion of one revolution of the engine, and responsive to the variations in said time intervals to identify the number of teeth sensed within each one of an integral number of cylinder-related subcycles of an engine cycle and for generating therefrom a manifestation of the total number of teeth on the flywheel of the engine.

4. Apparatus according to claim 3 wherein said processing means further comprises:

means for determining the average number of teeth sensed within a cylinder-related subcycle, for comparing the number of teeth sensed within each one of said cylinder-related subcycles to said average number, and for generating a corrected manifestation of the total number of teeth on the flywheel of the engine from only the numbers of teeth sensed for each cylinder-related subcycle which is within a given amount of said average number.

5. Apparatus for determining the number of teeth on the flywheel of an internal combustion engine comprising:

tooth sensing means adapted to be disposed to sense the passage of each tooth of the flywheel of an internal combustion engine when the engine is rotating, said means providing a tooth signal each time that a tooth of the flywheel passes in proximity to said tooth sensing means;

means for registering a plurality of standard data manifestations, each one representing a number indicative of a number of teeth permissible on a flywheel of an internal combustion engine of the type under test as established by industry standards;

processing means responsive to the tooth signals presented by said tooth sensing means to generate manifestations indicative of the time intervals between said tooth sensing means sensing successive teeth over a time period which is at least a significant portion of one revolution of the engine, and responsive to the variations in said time intervals to identify the number of teeth sensed across an integral number of cylinder-related subcycles of an engine cycle and for generating a measured data manifestation therefrom, and responsive to said registering means for comparing said measured data manifestation with each of said standard data manifestations and for selecting one of said standard data manifestations as a result of the comparison; and

means for presenting the selected one of said standard data manifestations as the determined number of teeth on the flywheel of the engine under test.

6. Apparatus for determining the number of teeth on the flywheel of an internal combustion engine comprising:

tooth sensing means adapted to be disposed to sense the passage of each tooth of the flywheel of an internal combustion engine when the engine is rotating, said means providing a tooth signal each time that a tooth of the flywheel passes in proximity to said tooth sensing means;

identification means adapted to be disposed for response to the presence of a particular member of the engine under test in a manner to present a signal corresponding to a known angle of revolution of the engine greater than the angle included by a plurality of said teeth, and for generating an ID signal in response to said engine member being in proximity with said identification means;

processing means, responsive to the tooth signals presented by said tooth sensing means and to said identification means when said identification means is disposed for response to said engine member, for measuring the number of said tooth signals provided as the engine rotates through a known angle determined by said ID signals and presenting a measured data manifestation indicative of the number of teeth on said flywheel when said ID signals are present, and alternatively, when said ID signals are not present, responsive to the tooth signals presented by said tooth sensing means to generate manifestations indicative of the time intervals between said tooth sensing means successive teeth for a number of teeth corresponding to at least a significant portion of one revolution of the engine, and responsive to the variations in said time intervals to identify the number of teeth sensed across an integral number of cylinder-related subcycles of an engine cycle and for generating said measured data manifestation therefrom.

7. In the method of determining the number of teeth on the flywheel of a slowly rotating internal combustion engine, the steps of:

electronically measuring the time intervals between the passage of corresponding successive ones of a large number of teeth of the flywheel past a fixed point;

maintaining a running count of teeth respectively corresponding to each of said time intervals;

from the magnitude of said time intervals, dividing said running count of teeth into cylinder-related subcycles of an engine revolution;

determining the number of teeth related to each of said subcycles; and

relating the number of teeth in each subcycle to a number of teeth corresponding to a full revolution of the engine to provide a measured number of teeth on the flywheel thereof.

8. In the method according to claim 7, the additional steps of:

comparing the number of teeth related to each subcycle to an average number of teeth per subcycle; and

relating the number of teeth for each of the subcycles which does not vary from the average of the subcycles by more than a given amount to a full revolution of the engine to provide a corrected measured number of teeth on the flywheel thereof.

9. In the method of determining the number of teeth on the flywheel of a slowly rotating internal combustion engine employing electronic processing apparatus including identification means adapted to be disposed for response to the presence of a particular member of the engine in a manner to present a cycle signal corresponding to a full engine cycle, and tooth sensing means adapted to be disposed to sense the passage of each tooth of the flywheel of the internal combustion engine when rotating, the steps of:

determining whether said identification means is providing said cycle signal;

if said cycle signal is present, counting the number of teeth sensed by said tooth sensing means between successive ones of said cycle signal to provide a measure of the number of teeth on the flywheel thereof; and

, alternatively,

if said cycle signal is not present, generating manifestations of the time intervals between the sensing of successive teeth over a number of teeth corresponding to at least a significant portion of one revolution of the engine, and responsive to the variation in said time intervals, identifying the number of teeth sensed across an integral number of cylinder-related subcycles of an engine cycle related said number to a full revolution of the engine to provide a measure of the number of teeth on the flywheel thereof.