Engine control strategy

Patent metadata

Field	Value
Publication number	US-10358996-B2
Application number	US-201615520578-A
Country	US
Kind code	B2
Filing date	Sep 30, 2016
Priority date	Nov 6, 2014
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

A method and apparatus controlling the fuel-to-air ratio of a fuel and air mixture supplied to an operating engine includes the steps of determining a first engine speed before enleanment of the mixture, determining a second engine speed near or at the end of a period of enleanment of the mixture, and after ending the enleanment, determining whether the engine speed recovers within a predetermined range of the first engine speed and if so determining a delta speed difference between the first and second speeds and using this delta speed difference as a factor in determining a change in the fuel-to-air ratio of the fuel mixture supplied to the engine.

First claim

The invention claimed is:

1. A method of controlling a fuel-to-air ratio of a fuel and air mixture supplied to an operating engine, comprising the steps of:
(a) determining a first engine speed before enleaning the fuel and air mixture supplied to the engine for a first number of engine revolutions;
(b) enleaning the fuel-to-air ratio of the mixture for a second number of engine revolutions greater than the first number of engine revolutions;
(c) determining a second engine speed for a third number of engine revolutions near or at the end of the second number of engine revolutions;
(d) after ending the enleaning, determining whether the engine speed recovers within a predetermined fourth number of engine revolutions greater than the third number of engine revolutions and, if so, determining a delta speed difference between the first engine speed and the second engine speed; and
(e) if the delta speed difference is a positive value enriching the fuel-to-air ratio of the mixture supplied to the engine or if the delta speed difference is a negative value enleaning the fuel-to-air ratio of the mixture supplied to the engine.

2. The method of claim 1 , further comprising repeating steps (a) through (d) to obtain a plurality of delta speed differences and if at least one half of the plurality of delta speed differences are a positive value enriching the fuel-to-air ratio supplied to the engine or if a negative value enleaning the fuel-to-air ratio of the mixture supplied to the engine.

3. The method of claim 2 , wherein the plurality of delta speed differences is at least five speed differences.

4. The method of claim 1 , which also comprises determining whether the engine is operating at a speed of at least 4,000 rpm during each of steps (a) through (d) and if not, not using the delta speed difference in step (e).

5. The method of claim 1 , which also comprises determining whether the engine is operating at a speed of at least 5,000 rpm during each of steps (a) through (d) and if not, not using the delta speed difference in step (e).

6. The method of claim 1 , which also comprises before step (a), determining whether any change in engine speed over at least 20 revolutions is less than 250 rpm and only if so, proceeding to step (a) of determining a first engine speed.

7. The method of claim 1 , which also comprises before step (a), determining whether any change in engine speed over at least 20 revolutions is less than 100 rpm and only if so, proceeding to step (a) of determining a first engine speed.

8. The method of claim 1 , wherein the first number of engine revolutions is at least 3 revolutions.

9. The method of claim 1 , wherein the first number of engine revolutions is at least 6 revolutions.

10. The method of claim 1 , wherein the third number of engine revolutions is at least 3 revolutions.

11. The method of claim 1 , wherein the third number of engine revolutions is at least 6 revolutions.

12. The method of claim 1 , wherein the first number of engine revolutions is the same as the third number of engine revolutions.

13. The method of claim 1 , wherein the second number of engine revolutions is at least 10 revolutions.

14. The method of claim 1 , wherein the second number of engine revolutions is at least 20 revolutions.

15. The method of claim 1 , wherein the second number of engine revolutions is at least 50 revolutions.

16. The method of claim 1 , wherein the fourth number of engine revolutions is at least 20 revolutions.

17. The method of claim 1 , wherein the fourth number of engine revolutions is at least 40 revolutions.

18. The method of claim 1 , wherein the fourth number of engine revolutions is at least 75 revolutions.

19. The method of claim 1 , which also comprises determining whether steps (a) through (d) of claim 1 have been completed within a predetermined fifth number of engine revolutions and if not, not using in step (e) any delta speed difference not determined within such fifth predetermined number of engine revolutions.

20. The method of claim 19 , wherein the fifth number of engine revolutions is at least 200 engine revolutions.

21. The method of claim 1 , further comprising repeating steps (a) through (d) to obtain a plurality of delta speed differences and if all of such plurality of delta speed differences are within a predetermined range then enleaning the fuel-to-air ratio of the fuel mixture supplied to the engine a small amount of not more than 1% of the fuel-to-air ratio of step (a) before the enleaning of the fuel-to-air ratio.

22. The method of claim 21 , wherein the predetermined range of such plurality of delta speed differences is in the range of −85 rpm to +100 rpm.

23. The method of claim 1 , further comprising repeating steps (a) through (d) to obtain a plurality of delta speed differences and, if within 25 engine revolutions, more than half of such plurality of delta speed differences are outside of a predetermined speed range and positive values, enriching the fuel-to-air ratio supplied to the engine or if outside of the predetermined speed range and negative values enleaning the fuel-to-air ratio of the mixture supplied to the engine by a relatively large change of more than 2.5% but not more than 5% of the fuel-to-air ratio of the mixture supplied to the engine before enleaning the fuel-to-air ratio of the mixture supplied to the engine.

24. The method of claim 23 , wherein for such plurality of delta speed differences such predetermined speed range is −85 rpm to +100 rpm.

25. The method of claim 1 , further comprising repeating steps (a) through (d) to obtain a plurality of delta speed differences, and if, within 50 engine revolutions and more than 25 engine revolutions, more than half of such plurality of delta speed differences are outside a predetermined speed range and positive values or outside of the predetermined speed range and negative values, a relatively medium change of the fuel-to-air ratio of the fuel mixture supplied to the engine is made of not more than 2½% of the fuel-to-air ratio of the fuel mixture supplied to the engine before enleaning the fuel-to-air ratio of the mixture supplied to the engine.

26. The method of claim 25 , wherein the predetermined range for such plurality of delta speed differences is −85 rpm to +100 rpm.

27. The method of claim 26 , wherein if more than half of such plurality of delta speed differences are positive values the fuel-to-air ratio of the mixture supplied to the engine is enriched or if more than half of such plurality of delta speed differences are negative values the fuel-to-air ratio of the mixture supplied to the engine is enleaned.

28. The method of claim 1 , wherein the fourth number of engine revolutions is at least six times greater than the third number of engine revolutions.

29. The method of claim 1 , wherein the second number of engine revolutions is at least three times greater than the first number of engine revolutions.

30. The method of claim 1 , wherein the fourth number of engine revolutions is at least equal to the second number of engine revolutions.

31. The method of claim 1 implemented by a microcontroller having an input of the speed of the engine and an output controlling a valve capable of changing the fuel-to-air ratio of the fuel and air mixture supplied to an operating engine.

Assignees

• Walbro Llc

Inventors

• Andersson Martin N
• Swanson Mark S
• Abei Takashi
• Healy Cyrus M

Classifications

• F02P5/045 Primary

  combined with electronic control of other engine functions, e.g. fuel injection (in general F02D37/02) · CPC title

• F02P5/1508

  with particular means during idling · CPC title

• F02D31/007

  controlling fuel supply · CPC title

• F02D31/008

  for idle speed control · CPC title

• F02D37/02

  one of the functions being ignition · CPC title