| 摘要 |
PROBLEM TO BE SOLVED: To feedback control the air-fuel ratio of an engine on the basis of the output of an air-fuel ratio sensor disposed in a collecting part of exhaust passages while surely restraining variation in the air-fuel ratio in two or more cylinders. SOLUTION: This air-fuel ratio control device finds a coefficientα#n of correction of basic fuel injection quantity by each cylinder so that the value (Fbaseb×α#n) obtained by multiplication of pre-correction basic fuel injection quantity Fbaseb by the coefficientα#n of correction of basic fuel injection quantity becomes a corrected basic fuel injection designated quantity Fbase#n required for actually injecting the Fbaseb of fuel in #n cylinder, and sets the final fuel injection designated quantity Fi#n of the #n cylinder to a value obtained by multiplication of (Fbaseb×α#n) by the feedback correction quantity DFi based on the output vabyfs of an upstream air-fuel ratio sensor. Theα#n is found by obtaining the feedback correction quantity DFiall obtained in the state of operating all cylinders and the feedback correction quantity DFi#else obtained in the state of pausing only the #n cylinder in the state of setting the final fuel injection designated quantity Fi#n of each cylinder all to (Fbaseb×DFi) from the formula:α#n = 4×DFiall - 3×DFi#else. COPYRIGHT: (C)2005,JPO&NCIPI
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