Method for determining a measurement value proportional to the compression of an internal combustion engine
First Claim
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1. A method for determining a measurement value which is derived from the current drain of the starter motor cranking an internal combustion engine and is proportional to the compression thereof, comprising:
- a) measuring a value proportional to at least the a-c component of the current during cranking;
b) integrating said value during each complete engine cycle between respective succeeding current minima with respect to time to obtain individual cylinder values;
c) integrating said value over a full engine cycle and averaging the integral to obtain an average value;
d) finding the difference between said average value and each individual cylinder value; and
e) adding each difference with its sign reversed, to the next following individual cylinder value to obtain improved values whereby the values thus obtained will serve as comparison measures for the compression in the individual cylinders.
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Abstract
A method for determining a measurement value proportional to the compression of an internal combustion engine, derived from the starter current, in which the a-c component of the starter current is integrated over the time between successive current minima and the difference between an integration value averaged over an engine cycle and integration values for individual cylinders obtained between succeeding current minima, is added, with the sign reversed, to the integration value for the next-following cylinder.
12 Citations
8 Claims
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1. A method for determining a measurement value which is derived from the current drain of the starter motor cranking an internal combustion engine and is proportional to the compression thereof, comprising:
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a) measuring a value proportional to at least the a-c component of the current during cranking; b) integrating said value during each complete engine cycle between respective succeeding current minima with respect to time to obtain individual cylinder values; c) integrating said value over a full engine cycle and averaging the integral to obtain an average value; d) finding the difference between said average value and each individual cylinder value; and e) adding each difference with its sign reversed, to the next following individual cylinder value to obtain improved values whereby the values thus obtained will serve as comparison measures for the compression in the individual cylinders. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Apparatus for determining a measurement value which is derived from the current drain of the starter motor cranking an internal combustion engine and is proportional to the compression thereof, comprising
a) a means for measuring a value proportional to at least the a-c component of the current during cranking; -
b) a means for integrating said value during each complete engine cycle between respective succeeding current minima with respect to time to obtain individual cylinder values; c) a means for integrating said value over a full engine cycle and averaging the integral to obtain an average value between said value; d) a means for finding the difference between said average value and each individual cylinder value; and e) a means for adding each difference with its sign reversed, to the next following individual cylinder value to obtain improved values whereby the values thus obtained will serve as comparison measures for the compression in the individual cylinders. - View Dependent Claims (8)
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Specification