Method and arrangement for determining misfires in an internal combustion engine
First Claim
1. A method for determining misfires in an internal combustion engine of a motor vehicle, the method comprising the steps of:
- first detecting misfires in the engine; and
,discontinuing the detection of the misfires after the first misfire is detected for a predetermined inhibit tie span.
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Abstract
The invention is directed to a method for determining misfires in an internal combustion engine of a motor vehicle. The determination is discontinued after a misfire under specific further conditions for a pregiven number of ignition strokes. When the misfire determination is not discontinued, then a check is made as to whether simple measurement value relationships apply which make a misfire very improbable. If such measurement value relationships are present, then the actual complicated misfire determination is discontinued. It is of special significance to count ignition strokes, which are counted in order to determine the relative frequency of misfires, only then when the above-mentioned conditions are all satisfied which determine as to whether a condition is present at all in which a determination of the misfire is purposeful. In this way, the decisive frequency determination is not influenced by the count of the ignition strokes which are not at all relevant to misfires. The above-mentioned procedure leads to a shortening of the average computation time because of the interruption of the misfire detection in many cases in which specific conditions are satisfied. Furthermore, the reliability of the detection of misfires is increased in that the final determination of misfires takes place only when specific preconditions are satisfied.
38 Citations
9 Claims
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1. A method for determining misfires in an internal combustion engine of a motor vehicle, the method comprising the steps of:
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first detecting misfires in the engine; and
,discontinuing the detection of the misfires after the first misfire is detected for a predetermined inhibit tie span. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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7. The method of claim 5, wherein the base condition is:
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space="preserve" listing-type="equation">Tn+1=Tn<
Tn+2-Tn+1wherein; T=the time span within which a pregiven crankshaft angle sector is passed through by the crankshaft; and
,n=the continuously advancing ignition stroke number.
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8. The method of claim 1, further comprising the steps of:
- counting the total number of ignition strokes with a first counter and counting the total number of misfires with a second counter in order to determine the relative frequency of misfires from the count values; and
, discontinuing the counting with the first counter as long as the misfire determination is discontinued.
- counting the total number of ignition strokes with a first counter and counting the total number of misfires with a second counter in order to determine the relative frequency of misfires from the count values; and
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9. An arrangement for determining misfires in an engine of a motor vehicle, the arrangement comprising:
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means for detecting misfires in the engine; and
,means for discontinuing the detection of the misfires after the first misfire is detected for a predetermined inhibit time span.
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Specification