| 摘要 |
<P>PROBLEM TO BE SOLVED: To determine catalyst deterioration by an O<SB>2</SB>sensor on the downstream side of catalyst while preventing determination error due to counter control in an O<SB>2</SB>storage quantity constant control system using an A/F sensor. <P>SOLUTION: In determining deterioration of a three-way catalyst based on track length of output of the O<SB>2</SB>sensor within a period of air-fuel ratio feedback control, operation of the track length is disconnected while output VAF of the A/F sensor is not within a prescribed range, and for prescribed period after output of the air-fuel ratio sensor becomes within the prescribed range. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
