| 摘要 |
PROBLEM TO BE SOLVED: To improve the air-fuel ratio controllability by determining the basic output fluctuation of each cylinder on the basis of the first and second angular speeds within the specific range of the first and second crank angles, and correcting the air-fuel ratio on the basis of the output fluctuation of each cylinder determined by subtracting a set value on the basis of the engine speed, from the basic output fluctuation. SOLUTION: A crank angle sensor 15 which generates an output pulse every rotation of a crank shaft by 30 deg. crank angle at the compression top dead center of each cylinder, is installed. That is, in a case when the first crank angle rangeθ1 is set on an area of an crank angle from the end of the compression stroke to the initial period of the explosion stroke, and the second crank angle rangeθ2 is set on a crank angle area of an intermediate period of the explosion stroke separated fromθ1 by a specific crank angle, the first and second angular speedωa,ωb of the crank shafts inθ1,θ2 are detected. Then the basic output fluctuation of each cylinder is determined on the basis ofωa,ωb, and the output fluctuation of each cylinder is determined by subtracting the set value determined corresponding to the engine speed, from the basic output fluctuation, to perform the correction of the air fuel ratio.
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