| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect the air-fuel ratio over a wide range by using an existing O2 sensor. <P>SOLUTION: An upper limit value VO2H and a lower limit value VO2L of a window width of largely changing in an output value VO2 of the O2 sensor to a change in the equivalent ratio Φ (Φ=1/λ, and λ: an air excessive rate) are compared with an output value VO2 (S13, S15), and when VO2>VO2H is realized, an equivalent ratio correction value k(Φ) is successively shifted to the rich side by a preset value ΔΦ1 (S14), and when VO2<VO2L is realized, the equivalent ratio correction value k(Φ) is successively shifted to the lean side by ΔΦ2 (S16), and the equivalent ration Φ (VO2) stored in an equivalent ratio map corresponding to the output value VO2 is updated in a corrected value by the equivalent ratio correction value k(Φ). The equivalent ratio Φ is stored in an area (VO2>VO2H, and VO2<VO2L) falling wide of the window width of the equivalent ratio map as indicated in a result drawing 4, and becomes relatively large in a change in the equivalent ratio Φ to a change in the output value VO2 of the O2 sensor, and the equivalent ratio Φ (the air-fuel ratio) can be detected over a wide range by few errors. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
