| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge gas cleaning device of an internal combustion engine capable of suppressing the deterioration of emission in relation to unexpected turbulence in an air-fuel ratio by optimally controlling the purifying ratio of an upstream catalyst and a downstream catalyst. SOLUTION: A second sensor output voltage indicated in Fig.5(b) and (d) and a second sensor target voltage Vtg at the upstream of the downstream catalyst indicated in Fig.5(c) are set corresponding to a third sensor output voltage. The target voltage Vtg is set by the second sensor output voltage and the third sensor output voltage to suppress the unnecessary correction of the target voltage Vtg and optimize the purifying ratio of the downstream catalyst, even when the second sensor output voltage indicates a stoichrometric condition, and when the third sensor output voltage indicates a rich condition. Consequently, the deterioration of emission with respect to the unexpected turbulence in the air-fuel ratio can be suppressed. COPYRIGHT: (C)2004,JPO
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