To provide a control device for an internal combustion engine, which accurately determines deterioration of an oxygen concentration sensor in a relatively simple method, regardless of the installation position of the sensor.
In regard to oxygen concentration sensor output SVO2, response delay compensation operation is performed and compensation sensor output SVO2INV is calculated (S21). The maximum value SVO2INVMAX and the minimum value SVO2INVMIN of the compensation sensor output SVO2INV are calculated (S23). When the maximum value SVO2INVMAX is below an upper threshold value SVO2INVTHH, it is determined that build up characteristics of the sensor output are deteriorated (S29, S32). When the minimum value SVO2INVMIN exceeds a lower threshold value SVO2INVTHL, it is determined that build down characteristics of the sensor output are deteriorated (S30, S34).
COPYRIGHT: (C)2008,JPO&INPIT
MAKI HIDETAKA
SUEHIRO YUKIO
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