Method for detecting engine misfire and for fuel control
First Claim
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1. The method of detecting misfire in an internal combustion engine during start up comprising the steps of:
- sensing first engine speeds at positions midway between top dead center positions and second engine speeds at positions between each midway position and the previous top dead center position,during initial cranking, storing first speeds as cranking speed, andcomparing the first speed with the second speed during the combustion period of each cylinder and with the cranking speed whereby a failure to increase speed over the cranking speed and over the second speed denotes misfire for that cylinder.
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Abstract
Misfire is detected in an internal combustion engine during its starting mode by analyzing the engine speed profile. Average speed is determined for 60° increments of crankshaft rotation. If an increment midway between top dead center positions has a higher speed than the previous increment and a higher speed than cranking speed, combustion occurred, otherwise a misfire occurred. When misfires are detected for a particular cylinder the calculated fuel allotment for that cylinder is reduced in accordance with the number of consecutive misfires for that cylinder.
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Citations
7 Claims
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1. The method of detecting misfire in an internal combustion engine during start up comprising the steps of:
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sensing first engine speeds at positions midway between top dead center positions and second engine speeds at positions between each midway position and the previous top dead center position, during initial cranking, storing first speeds as cranking speed, and comparing the first speed with the second speed during the combustion period of each cylinder and with the cranking speed whereby a failure to increase speed over the cranking speed and over the second speed denotes misfire for that cylinder. - View Dependent Claims (2, 3)
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4. The method of controlling fuel during engine cranking on the basis of misfire information comprising the steps of:
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sensing first engine speeds at positions midway between top dead center positions and second engine speeds at positions between each midway position and the previous top dead center position, during initial cranking, storing first speeds as cranking speed, comparing the first speed with the second speed during the combustion period of each cylinder and with the cranking speed whereby a failure to increase speed over the cranking speed and over the second speed denotes misfire for that cylinder while a speed increase denotes combustion for that cylinder, measuring manifold pressure, calculating a fuel injection amount for each cylinder from the measured pressure and engine speed, and adjusting the fuel amount in response to the misfire history of the cylinder. - View Dependent Claims (5, 6, 7)
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Specification