SENSOR LEARNING APPARATUS

摘要

PROBLEM TO BE SOLVED: To further enhance learning (correction) accuracy of a sensor capable of detecting ammonia.SOLUTION: A sensor learning apparatus for detecting ammonia at a downstream of a selective reduction type NOx catalyst (SCR catalyst) includes: ammonia adsorption quantity estimation means for estimating ammonia quantity adsorbed by the SCR catalyst; temperature detection means for detecting or estimating a temperature of the SCR catalyst; ammonia concentration estimation means for estimating an ammonia concentration in exhaust air flowing out from the SCR catalyst on the basis of the ammonia quantity estimated by the ammonia adsorption quantity estimation means and a rise speed of the temperature detected or estimated by the temperature detection means; and learning means which when the ammonia concentration estimated by the ammonia concentration estimation means is larger than a threshold, executes learning of a sensor output value on the basis of the ammonia concentration estimated by the ammonia concentration estimation means.