| 摘要 |
An output calibration apparatus for an NOx sensor according to the present invention includes a urea addition valve provided in an exhaust passage in an internal combustion engine to allow urea to be added to inside of the exhaust passage, and an NOx sensor provided at least downstream of the urea addition valve, the NOx sensor being capable of detecting not only an NOx concentration but also an ammonia concentration. The output calibration apparatus executes fuel cut on the internal combustion engine, and calibrates a gain of the NOx sensor based on ammonia obtained from the urea added via the urea addition valve during execution of the fuel cut. The ammonia obtained from the urea added during execution of the fuel cut is used as standard gas to calibrate the gain of the NOx sensor. |
