Method and apparatus for engine monitoring

• US 5,631,411 A
• Filed: 12/04/1995
• Issued: 05/20/1997
• Est. Priority Date: 04/30/1992
• Status: Expired due to Term

• Current Assignee: AVL Gesellschaft Fur Verbrennungskraftmaschinen und Messtechnik mbH PROF Drdrhc HANS List, AVL Gesellschaft fuer Verbrennungskraftmaschinen und Messtechnik mbH (List Privatstiftung)
• Original Assignee: AVL Gesellschaft Fur Verbrennungskraftmaschinen und Messtechnik mbH PROF Drdrhc HANS List
• Inventors: Harms, Klaus C., Koegeler, Hans-Michael, Kunzfeld, Wilhelm, Schiffbaenker, Herbert
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US08/567,067
• Time in Patent Office: 533 Days
• Field of Search: 73/35.03, 73/35.04, 73/116, 73/117.3, 73/862.192, 123/419, 123/436, 364/431.07, 364/431.08
• US Class Current: 73/114.15
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: G01M 15/046 by monitoring revolutions for detecting misfire G01M15/11

Abstract

The invention presented herein makes it possible to construct and operate an engine monitoring apparatus that calculates the engine speed, the engine load and/or engine monitoring quantities basically only from the measurement of an angular velocity curve at the gear rim of an internal combustion engine (optionally, from a plurality of angular velocity curves). The basis is thus simultaneously created for monitoring all other measured quantities within narrow limits that are dependent on load and speed. The invention can also be utilized for control purposes or for measuring power.

Claims

1. A method for testing an internal combustion engine, whereby measurements of a rotation angle velocity that is dependent on a crank angle are continuously implemented and dimensional quantities for speed and torque are identified on a basis of an evaluation thereof, wherein an average oscillation amplitude corresponding to the ignition frequency of a total energy level is used as a dimensional quantity for torque, the total energy level is calculated from a momentary rotational angle velocity and from a momentary moment of inertia which are dependent on the crank angle and take into account a kinetic energy of oscillating masses of said engine.

2. The method of claim 1 wherein the average oscillation amplitude is identified on the basis of an ordering analysis with an FFT algorithm.

3. A method according to claim 1, wherein said curve of the rotational angle velocity is first conditioned by a signal editing and then evaluated.

4. A method according to claim 1, wherein said curve of the quantities derived from the rotational angle velocity is first conditioned by a signal editing and then evaluated.

5. A method according to claim 3, wherein said editing comprises an averaging by superimposing curves from a plurality of operating cycles.

6. A method according to claim 3, wherein said editing comprises an average by superimposing curves from a plurality of ignition periods.

7. A method according to claim 3, wherein said editing comprises a smoothing averaging.

8. A method according to claim 3, wherein the curve of the rotational angle velocity is calculated with a defined angular resolution so that a plurality of reference points in a power of two is available per cycle.

12. A method according to claim 1, wherein, for calculating the total energy level curve, the curve of the rotational angle velocity of a respective internal combustion engine that is dependent on the crank angle is calculated once without and once with additional load on a basis of an additional, known moment of inertia, wherefrom a effective moment of inertia is calculated by comparing respective measured results.

15. A method according to claim 12, wherein the additional load is produced by an additional fly wheel driven by the internal combustion engine.

9. A method for testing internal combustion engines, whereby measurements of the rotation angle velocity that is dependent on the crank angle are continuously implemented and dimensional quantities for speed and torque are identified on the basis of the evaluation thereof, wherein an average fluctuation amplitude in an energy level curve that is calculated from a curve of the rotational angle velocity at an ignition frequency is utilized as a dimensional quantity for torque, and wherein the average fluctuation amplitude of the energy level curve at the ignition frequency is identified on the basis of an ordering analysis with an FFT algorithm.

10. A method according to claim 9, wherein amplitude elevations for crank shaft orderings versus the ignition frequency are calculated from an ordering spectrum of the energy level curve and are employed as a measure for uniformity of individual cylinder outputs.

11. A method according to claim 10, wherein the amplitude elevations for crank shaft ordering versus the ignition frequency are calculated from the ordering spectrum of the energy level curve and are employed as a measure for a true running of the internal combustion engine.

13. A method according to claim 11, wherein, for calculating the total energy level curve, the curve of the rotational angle velocity of the respective internal combustion engine that is dependent on the crank angle is calculated once without and once with additional load on a basis of an additional, known moment of friction.

14. A method according to claim 13, wherein said additional moment of friction is generated via an electrical load resistor connected into a generator present at the interval combustion engine.

16. A method according to claim 13, wherein the additional load is produced by a braking means.

17. An apparatus for testing internal combustion engines, comprising a measuring means for identifying a rotational angle speed that is dependent on crank angle and comprising an evaluation unit in communication therewith for calculating quantities for speed and torque, wherein the evaluation unit comprises a means for calculating an average oscillation amplitude corresponding to the ignition frequency of a total energy level, and a means for calculating a total energy level from a momentary rotational angle velocity and from a momentary moment of inertia which are dependent on the crank angle and which take into account a kinetic energy of oscillating masses of said engine, the evaluation unit using the average oscillation amplitude as a dimensional quantity for torque.

18. The apparatus of claim 17 wherein the evaluation unit identifies the average oscillation amplitude on the basis of an ordering analysis with an FFT algorithm.

19. An apparatus according to claim 17, wherein the evaluation unit is preceded by a signal editing unit.

20. An apparatus according to claim 17, wherein a fly wheel having a known moment of inertia is provided to be additionally driven by the internal combustion engine.

21. An apparatus according to claim 17, wherein a braking means representing a defined load is provided for engaging an output shaft of the internal combustion engine.

22. An apparatus according to claim 17, wherein a generator is connected to an output shaft of said internal combustion engine, which generator has a defined electrical load resistor connected to it.

23. A method for testing an internal combustion engine, comprising the steps:

continuously measuring a rotation angle velocity that is dependent on a crank angle;

calculating a total energy level that is calculated

from a momentary rotational angle velocity and from a momentary moment of inertia, which are dependent on the crank angle and take into account a kinetic energy of oscillating masses of said engine;

determining an average oscillation amplitude corresponding to the ignition frequency in said total energy level; and

utilizing said average oscillation amplitude as a quantity for torque.

24. The method of claim 23 wherein the average oscillation amplitude is identified on the basis of an ordering analysis with an FFT algorithm.