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(11) | EP 2 075 662 A8 |
| (12) | CORRECTED EUROPEAN PATENT APPLICATION |
| Note: Bibliography reflects the latest situation |
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| (54) | Control apparatus and method |
| (57) A control apparatus which can improve the accuracy of control of a controlled variable
by a control input exhibiting a periodic fluctuating behavior. The control apparatus
calculates an air-fuel ratio correction value DKCMD such that the output from an oxygen
concentration sensor converges to a target output, and calculate a modulated value
DKCMD_DSM by modulating DKCMD with an algorithm to which is applied a ΔΣ modulation
algorithm. Further, the control apparatus calculates a reference air-fuel ratio KCMDBS
according to an exhaust gas volume, calculates a model modification coefficient KTRQFF
using a modification coefficient calculated such that DKCMD become equal to 0, calculates
an adaptive reference air-fuel ratio KCMDADP by the equation of KCMDADP = KCMDBS x
KTRQFF, and calculates a target air-fuel ratio KCMD by the equation of KCMD = KCMADP
+ DKCMD_DSM.
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