| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To carry out precise and reliable diagnosis regardless of the sulfur concentration of fuel. <P>SOLUTION: A plurality of active air/fuel ratio control having different center air/fuel ratios is executed, thereby measuring a plurality of oxygen occlusion amount corresponding to respective center air/fuel ratios. The sulfur concentration of fuel is estimated according to the change rate of the oxygen occulusion amount to change of the center air/furl ratio. According to the estimated sulfur concentration, an oxygen occulusion capacity measuring value is corrected if necessary. The oxygen occulusion capacity measuring value is corrected to be a precise value without sulfur influence, so that the precise and reliable diagnosis can be executed. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
