Method for recognizing erratic combustion
First Claim
1. A method for recognizing erratic combustion in a multicylinder internal combustion engine by using a time measuring device to measure successive time periods which a crankshaft needs to rotate through predetermined angles during operating strokes of successive cylinders, which comprises:
- (a) determining a static component by using a calculating device to subtract a time period of the next cylinder in an ignition order from the time period of a cylinder to be examined;
(b) multiplying the static component with a standardizing factor by using the calculating device;
(c) determining a dynamic component by using the calculating device to subtract a time period of a next cylinder in the ignition order from a time period of a preceding cylinder in the ignition order, and negating the determined dynamic component;
(d) forming a change component by calculating a value (Tn-z -Tn)-(Tn -Tn+z), where T is a time period, n is an index indicating a cylinder, and z is an integer, and multiplying the value with a weighting factor, wherein the change component is set equal to zero if the change component is negative; and
wherein a sliding average is formed of the change component;
(e) determining a lack of smoothness value from addition of the static component, the dynamic component, and the sliding average; and
(f) recognizing a combustion misfire if the smoothness value falls below a given limit value.
2 Assignments
0 Petitions
Accused Products
Abstract
A method is provided for recognizing erratic combustion in a multicylinder internal combustion engine by using a time measuring device to measure successive time periods which a crankshaft needs to rotate through predetermined angles during operating strokes of successive cylinders. The method includes determining a static component by using a calculating device to subtract a time period of the next cylinder in an ignition order from the time period of a cylinder to be examined. The static component is multiplied with a standardizing factor by using the calculating device. A dynamic component is determined by using the calculating device to subtract a time period of a next cylinder in the ignition order from a time period of a preceding cylinder in the ignition order, and a dynamic component is negated. A change component for a lack of smoothness value is formed, the lack of smoothness value is multiplied with a weighting factor to form a weighted value, and the weighted value is set equal to zero if the weighted value is negative. A sliding average is formed from the weighted value in a sliding averaging process. A lack of smoothness value is determined from addition of the static component, the dynamic component, and the sliding average. A combustion misfire is recognized if the smoothness value falls below a given limit value.
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Citations
7 Claims
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1. A method for recognizing erratic combustion in a multicylinder internal combustion engine by using a time measuring device to measure successive time periods which a crankshaft needs to rotate through predetermined angles during operating strokes of successive cylinders, which comprises:
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(a) determining a static component by using a calculating device to subtract a time period of the next cylinder in an ignition order from the time period of a cylinder to be examined; (b) multiplying the static component with a standardizing factor by using the calculating device; (c) determining a dynamic component by using the calculating device to subtract a time period of a next cylinder in the ignition order from a time period of a preceding cylinder in the ignition order, and negating the determined dynamic component; (d) forming a change component by calculating a value (Tn-z -Tn)-(Tn -Tn+z), where T is a time period, n is an index indicating a cylinder, and z is an integer, and multiplying the value with a weighting factor, wherein the change component is set equal to zero if the change component is negative; and
wherein a sliding average is formed of the change component;(e) determining a lack of smoothness value from addition of the static component, the dynamic component, and the sliding average; and (f) recognizing a combustion misfire if the smoothness value falls below a given limit value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification