Patent ID: 8245497

Claim:
An exhaust emission control device for an internal combustion engine, the device comprising: an NOx adsorbent which is positioned in an exhaust path of the internal combustion engine; NOx adsorption amount measurement means for measuring the amount of NOx that is adsorbed by the NOx adsorbent while the internal combustion engine is in operation; water adsorption amount measurement means for measuring the amount of water that is adsorbed by the NOx adsorbent while the internal combustion engine is in operation; reference value storage means for storing a reference value of an NOx adsorption amount with respect to a water adsorption amount; comparison means for comparing a measured NOx adsorption amount against a reference value of the NOx adsorption amount with respect to a measured water adsorption amount; and signal output means for outputting a signal in which the result of the comparison is reflected.