| 摘要 |
PROBLEM TO BE SOLVED: To provide a device for generating a deterioration signal of an oxygen sensor capable of changing a gain of a sensor output signal by using different gain rates between the case that an air fuel ratio of exhaust gas is on a rich side and the case that the same is on a lean side, in quasi-generating sensor output signals outputted as deterioration signals by the oxygen sensor of which the sensor output suddenly changes at a theoretical air fuel ratio when the sensor is deteriorateed. SOLUTION: A gain is changed by using a rich gain rate RichGain (S22: Yes, S23) when a voltage Vin of a reference signal acquired from a reference sensor every 1ms is greater than a predetermined threshold GainThreshold, and the gain is changed by using a lean gain rate LeanGain (S22: No, S25:Yes, S26) when the voltage is lower than a predetermined threshold, and a deterioration signal (voltage Vout) is generated and outputted. The device is constituted in such a manner that the rich gain rate and the lean gain rate can be individually set. COPYRIGHT: (C)2008,JPO&INPIT
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