Combustion control based on a signal from an engine vibration sensor

• US 7,810,469 B2
• Filed: 09/06/2006
• Issued: 10/12/2010
• Est. Priority Date: 09/06/2006
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Roettger, Daniel, Karvounis, Evangelos, Brewbaker, Thomas, Brehob, Diana, Vigild, Christian, Tumelaire, Charles, Hopka, Michael, van Nieuwstadt, Michiel
• Primary Examiner(s): Vo; Hieu T
• Application Number:
  US11/470,385
• Publication Number:
  US 20080053405A1
• Time in Patent Office: 1,497 Days
• Field of Search: 123/406.21, 123/406.24, 123/406.26, 731/173, 701/111, 701/110
• US Class Current: 123/406.26
• CPC Class Codes: F02B 1/12 with compression ignition with fuel-air charge ignited by compression ignition of an additional fuel F02B7/00
• CPC Class Codes: F02D 2041/281 between sensors and control unit
• CPC Class Codes: F02D 23/00 Controlling engines characterised by their being supercharged
• CPC Class Codes: F02D 35/021 using an ionic current sensor
• CPC Class Codes: F02D 35/027 using knock sensors
• CPC Class Codes: F02D 35/028 by determining the combustion timing or phasing
• CPC Class Codes: F02D 41/0052 Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
• CPC Class Codes: F02D 41/402 Multiple injections
• CPC Class Codes: F02M 26/05 High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
• CPC Class Codes: G01M 15/12 by monitoring vibrations

Abstract

Feedback control of an internal combustion engine is performed based on a signal from a vibration sensor and a crankshaft angle sensor. An energy factor can be computed based on these sensor signals. A vector of energy factor can be computed as a function of crank angle degree over a particular window of engine rotation of interest. Based on the energy factor vector, combustion phasing can be estimated.

Claims

1. An internal combustion engine, comprising:

an accelerometer affixed to the engine;

an engine rotation sensor proximate the engine; and

an electronic control unit electronically coupled to the engine and said accelerometer, said electronic control unit adjusting engine parameters based on signals from said accelerometer and said engine rotation sensor, said signals being used to estimate combustion phasing, wherein said engine parameters are at least one of injection timing and EGR rate, the engine having an EGR system which comprises a duct connecting an engine intake with an engine exhaust via an EGR valve, the engine also having one fuel injector per engine cylinder.

2. The engine of claim 1 wherein said engine has multiple accelerometers and signals from more than one accelerometer are averaged to compute combustion phasing in an engine cylinder.

3. The engine of claim 2 wherein said signal from said accelerometer is windowed to provide a dataset over a desired interval of engine rotation roughly corresponding with combustion in a particular engine cylinder.

4. The engine of claim 2 wherein said accelerometer signal is digitally acquired and filtered in said electronic control unit.

5. The engine of claim 1 wherein said combustion phasing is determined based on applying a function to said signal and integrating said accelerometer signal.

6. The engine of claim 5 wherein a combustion intensity is determined based on said combustion phasing.

7. The engine of claim 6 wherein said combustion intensity is based on a number of crank angle degrees for the major portion of the combustion event to occur.

8. The engine of claim 6 wherein said combustion intensity is based on a number of crank angle degrees between the 10% and 90% combustion times.

9. The engine of claim 5 wherein said function comprises one of:

squaring, cubing, and taking the fourth power.

10. A method for controlling an internal combustion engine, comprising:

estimating combustion phase based on a signal from a vibration sensor coupled to the engine, said sensor detecting engine vibrations; and

adjusting an engine parameter based on said estimated combustion phase.

11. The method of claim 10 wherein said engine parameter is one of:

number of injections per power stroke, injection timing, EGR rate, boost pressure, amount of fuel inducted, and injection rate.

12. The method of claim 10 wherein said internal combustion engine is a compression ignition engine.

13. The method of claim 10 wherein said engine parameter is one of:

spark timing, injection timing, EGR rate, boost pressure, air-fuel ratio, and injection rate.

14. The method of claim 13 wherein said internal combustion engine is a spark ignition engine and said method is applied when said engine is undergoing non-knocking combustion.

15. The method of claim 10 wherein said sensor is an accelerometer affixed to the engine.

16. The method of claim 10, further comprising:

acquiring a voltage or charge signal from said vibration sensor multiple times during a window of engine rotation.

17. The method of claim 16, further comprising:

adjusting a level of said acquired signal so that the mean value of the acquired signal values is zero.

18. The method of claim 17, further comprising:

filtering said adjusted, acquired signal values with a bandpass filter.

19. The method of claim 18 wherein said bandpass filter has calibratable upper and lower frequency limits.

20. The method of claim 19, further comprising:

rectifying said signal values when said power is odd.

21. The method of claim 18, further comprising:

raising said filtered, adjusted, acquired signal values to a predetermined power to obtain unfiltered energy factor values.

22. The method of claim 18 wherein said predetermined power is 1, 2, 3, or 4.

23. The method of claim 10, further comprising:

filtering said unfiltered energy factor values with a lowpass filter, said lowpass filter being calibratable.

24. The method of claim 23 wherein said lowpass and bandpass filters is run in one of a forward and a forward-backward mode.

25. The method of claim 23, further comprising:

summing said filtered energy factor values to obtain an energy vector.

26. The method of claim 25, further comprising:

determining a crank angle, θ

p, at which p % of the maximum energy factor value has been obtained by finding θ

p which most closely satisfies;

E<sub>θ

p</sub>=p·

E<sub>θ

n</sub>

where E<sub>θ

n</sub> is the maximum energy factor value and E<sub>θ

p</sub> is the energy factor value at θ

p.

27. The method of claim 26, further comprising:

estimating mass fraction burned crank angle based on the energy factor vector and engine rpm.

28. A method for controlling an internal combustion engine, comprising:

estimating combustion phase based on an energy factor, said energy factor being based on the absolute value of the power of one, two, three, or four of a signal from a vibration sensor coupled to the engine, said sensor used for detecting engine vibrations during a portion of engine rotation which corresponds roughly when combustion is occurring in one of the engine'"'"'s cylinders.

29. The method of claim 28 wherein said vibration sensor signal is bandpass filtered with calibratable upper and lower limits, said bandpass filtering occurring prior to raising to said power of said sensor signal.

30. The method of claim 29 wherein said calibratable upper and lower limits are based on at least one of engine architecture and engine operating conditions.

31. The method of claim 28 wherein said power of said sensor signal is filtered in a lowpass filter which removes high frequency components, said lowpass filter cutoff being calibratable.

32. The method of claim 28 wherein said power of said sensor signal is summed to provide an energy factor vector:

33. The method of claim 32 wherein said energy factor vector is computed over a window of crankangle degrees from to θ

₀ to θ

n, said θ

₀ to θ

n being calibratable based on engine architecture and engine operating conditions.