| 摘要 |
PROBLEM TO BE SOLVED: To provide a detection error preventing device of an oxygen concentration sensor which suspends detection by means of the oxygen concentration sensor to prevent a detection error at a time when braking operations are repeatedly performed while a small amount of air is taken in, for example, during idling. SOLUTION: The oxygen concentration sensor which detects the concentration of the oxygen in an exhaust gas is mounted to an internal combustion engine which comprises a master back which doubles a braking force using the suction pipe negative pressure of the internal combustion engine. The oxygen concentration sensor comprises an air-fuel ratio feed back control means which controls the air-fuel ration while targeting an actual air-fuel ratio on the basis of the detected value of the sensor, a master back operation time determining means in which a sensing means which senses the operation of the master back determines whether a master back operation times are not less than a judgement value or not in a predetermined time period, a detection suspending means which suspends detection by the oxygen concentration sensor in order to judge as abnormal the time not less than the judgement value spent from a rich judgement voltage to a lean judgement voltage or the time not less than judgement value spent from the lean judgement voltage to the rich judgement voltage when the master back operation time determining means determines the master back operation times to be not less than the judgement value. COPYRIGHT: (C)2006,JPO&NCIPI
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