| 摘要 |
PROBLEM TO BE SOLVED: To adequately correct air-fuel ratio control and to keep a good exhaust characteristic based on output of a sensor disposed downstream of a catalyst of the most downstream of an exhaust gas system, in an exhaust gas purification device that realizes low emission where final concentrations of HC and CO components are tens ppm or less. SOLUTION: Oxide concentration sensors 18, 20 are respectively disposed upstream of a ternary catalyst 14 of the most upstream of the exhaust gas system and downstream of a ternary catalyst 17 of the most downstream. When output VO2 of the oxide concentration sensor 20 exceeds a predetermined voltage VO2H2, a correction coefficient KCMDLS is calculated (S12, S13) according to the output VO2, and a desired air-fuel ratio coefficient KCMD is corrected (S16) using the correction coefficient KCMDLS. The oxide concentration sensor 20 can detect increase of concentration of hydrogen generated by water gas reaction in an extremely low state of unburned component concentration.
|
