Claims
- 1. A method for cylinder equalization, which comprises:providing an internal combustion engine having a crank shaft and cylinders operating by direct injection, each cylinder having a fuel injection quantity; detecting a speed value of the crankshaft in a quasi-stationary and in a dynamic operating state of the internal combustion engine; correcting the speed values with a mean-value filter having an envelope delay of zero to form a corrected speed value; calculating a change in the kinetic energy of the crankshaft in an expansion interval of a cylinder from the corrected speed value; deriving from the change in kinetic energy of the crankshaft a relative measure for each cylinder that contains information on too much or too little injected fuel quantity; calculating correction terms for the injection time from this measure; and changing each cylinder-specific injection time by applying a respective cylinder-specific correction term so that the internal combustion engine runs more smoothly.
- 2. The method according to claim 1, wherein the correction of the speed values is performed according to the following relationship: n^OT(i+1)=nOT(i+1)-n_OT(i+1)-n_OT(i)2n^OT(i)=nOT(i)-n_OT(i+1)-n_OT(i)2where {circumflex over (n)}OT(i), {circumflex over (n)}OT(i+1) is the corrected speed of the cylinder i and i+1, respectively, over a working cycle, and {overscore (n)}OT(i), {overscore (n)}OT(i+1) is the mean value of the speed of the cylinder i and i+1, respectively, over a working cycle.
- 3. The method according to claim 2, wherein the internal combustion engine is a 4-cylinder internal combustion engine and the mean value of the cylinder is calculated as:{overscore (n)}OT(i)=⅛nOT(i−2)+¼nOT(i−1)+¼nOT(i)+¼nOT(i+1)+⅛nOT(i+2).
- 4. The method according to claim 2, wherein the internal combustion engine is a 4-cylinder internal combustion engine and the mean value of the cylinder is calculated as:{overscore (n)}OT(i+1)=⅛nOT(i−1)+¼nOT(1)+¼nOT(i+1)+¼nOT(i+2)+⅛nOT(i+3).
- 5. The method according to claim 1, wherein the change in the kinetic energy are referred to a value which specifies a maximum fuel energy which can be fed in an interval, and the relative measure is calculated therefrom.
- 6. The method according to claim 1, wherein the change in the kinetic energy is calculated in accordance with the following equationΔEkin(i)=½·θ·({circumflex over (n)}OT(i+1)−{circumflex over (n)}OT(i)2) and the measure is determined therefrom asRZ(i)Knorm·({circumflex over (n)}OT(k,i+1)2−{circumflex over (n)}OT(k,i)) whereθ is the mean moment of inertia of the crankshaft, Hu is the lower calorific value for the fuel used, mBmax is the maximum injectable fuel quantity, {circumflex over (n)}OT(i) is the corrected speed at the top dead center of the cylinder i, {circumflex over (n)}OT(i+1) is the corrected speed at the top dead center of the cylinder i+1, and Knorm is a normalizing factor which has the value of θ2· 1HumBmax(2π60)2.
- 7. The method according to claim 1, wherein the correction terms by which the values for the injection times are multiplied are calculated from the calculated measures.
- 8. The method according to claim 7, wherein the correction terms are calculated as [δZ(1),kδZ(2),kδZ(3),kδZ(4),k]=[δZ(1),k-1δZ(2),k-1δZ(3),k-1δZ(4),k-1]+α· [-(RZ(1),kRZ(2),kRZ(3),kRZ(4),k)+13·(RZ(2),k+RZ(3),k+RZ(4),kRZ(3),k+RZ(4),k+RZ(1),kRZ(4),k+RZ(1),k+RZ(2),kRZ(1),k+RZ(2),k+RZ(3),k)]with [”Z(1),0”Z(2),0”Z(3),0”Z(4),0]=[1111]as an initialization value, and whereδZ(i), k is the correction term for cylinder i after adaptation step k, RZ(i),k is a residue of the cylinder i relative to the adaptation step k, and α is a positive, freely selectable adaptation parameter between 0 and 1 which fixes the rate of the adaptation.
Priority Claims (1)
Number |
Date |
Country |
Kind |
198 14 155 |
Mar 1998 |
DE |
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CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of copending international application PCT/DE99/00654, filed Mar. 10, 1999, which designated the United States.
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Number |
Name |
Date |
Kind |
4705000 |
Matsumura et al. |
Nov 1987 |
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6082187 |
Schricker et al. |
Jul 2000 |
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Foreign Referenced Citations (4)
Number |
Date |
Country |
41 22 139 A1 |
Jan 1993 |
DE |
196 27 540 A1 |
Aug 1997 |
DE |
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198 12 305-A1 |
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DE |
Continuations (1)
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Number |
Date |
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Parent |
PCT/DE99/00654 |
Mar 1999 |
US |
Child |
09/677562 |
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US |