| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a failure diagnosis method of a gas sensor capable of more accurately and quickly making diagnosis of a gas sensor whether in a failure state, and to provide a failure diagnosis device for the same. <P>SOLUTION: A period until the number of times that the air-fuel ratio of fuel-air mixture supplied into an engine inverts from a rich side to a lean side reaches a predetermined number of times (for example five times), set as a target air-fuel ratio inverting number of times, is a diagnosis period. Besides, a detection signal (an air-fuel ratio measured value) corresponding to the concentration of a specified gas component in an exhausted gas is acquired with a gas sensor at a predetermined interval (ten milli seconds), and the actual number of transferring times, which is the number of transferring times of the detected signal from the rich side to the lean side during the diagnosis period, is obtained. And based on the transferring times during the diagnosis period, a diagnosis is made whether the responsivity of output of the gas sensor is in the failure state. <P>COPYRIGHT: (C)2008,JPO&INPIT |
