Engine speed prediction method for engine control
First Claim
1. A method of predicting engine speed of an internal combustion engine having a plurality of cylinders comprising the steps of:
- generating a plurality of crankshaft position reference pulses for each cylinder event to thereby define a plurality of reference periods for each cylinder event;
measuring reference periods between adjacent ones of said reference pulses;
determining a trend of reference period change by comparing the most recent reference period with an earlier period;
projecting a future reference period at least one period beyond the current period by selecting a measured reference period from the most recently completed cylinder event as a base period, the base period having the same position in its cylinder event as the future reference period occupies in its respective cylinder event, determining a gain factor, and calculating the future reference period from the base period as adjusted by the product of the reference period change and the gain factor.
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Accused Products
Abstract
Using a plurality of engine position reference pulses for each cylinder event, several reference periods for each cylinder event are defined and the engine speed can be accurately predicted for the current reference period and for future reference periods using position data from only the current combustion interval. For speed control the start of injection and start of spark dwell are computed based on predicted engine speeds for periods after those functions are started. Adaptive prediction gains are used to update the prediction algorithms to reflect the current engine operation conditions and minimize prediction error.
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Citations
6 Claims
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1. A method of predicting engine speed of an internal combustion engine having a plurality of cylinders comprising the steps of:
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generating a plurality of crankshaft position reference pulses for each cylinder event to thereby define a plurality of reference periods for each cylinder event; measuring reference periods between adjacent ones of said reference pulses; determining a trend of reference period change by comparing the most recent reference period with an earlier period; projecting a future reference period at least one period beyond the current period by selecting a measured reference period from the most recently completed cylinder event as a base period, the base period having the same position in its cylinder event as the future reference period occupies in its respective cylinder event, determining a gain factor, and calculating the future reference period from the base period as adjusted by the product of the reference period change and the gain factor. - View Dependent Claims (2, 3)
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4. A method of controlling speed of a multi-cylinder internal combustion engine to a target speed in a given crank angle wherein timed operating parameters regulate the engine speed, comprising the steps of:
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generating a plurality of crankshaft position reference pulses for each cylinder event to thereby define a plurality of reference periods for each cylinder event; measuring reference periods between adjacent ones of said reference pulses; determining a trend of reference period change by comparing the most recently measured reference period with an earlier period; projecting a future reference period at least one period beyond the current period and containing the given crank angle by selecting a measured reference period from the most recently completed cylinder event as a base period, the base period having the same position in its cylinder event as the future reference period occupies in its respective cylinder event, and calculating the future reference period from the base period as adjusted by the product of the reference period change and an adaptive gain factor; determining from the target speed and the calculated future reference period a speed error; determining timing of operating parameters required to mitigate the speed error; if any parameter is timed to begin in the current reference period then beginning the parameter operation; and if any parameter is timed to begin after the current period, then iterating the above steps to attain a reference period when such parameter is to begin. - View Dependent Claims (5, 6)
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Specification