EXHAUST EMISSION CONTROL DEVICE FOR ENGINE AND METHOD OF CONTROLLING AN EXHAUST EMISSION OF AN ENGINE AND A COMPUTER PROGRAM PRODUCT CAPABLE OF PERFORMING STEPS OF THE METHOD

The exhaust emission control device for an engine is provided with a first purifying catalyst 148 including an HC adsorbent 43 that adsorbs HC at a low temperature and releases HC at a high temperature and a diesel oxidation catalyst 42 capable of oxidizing HC, a second purifying catalyst 148 including a NOx catalyst 41 capable of storing NOx contained in exhaust, a NOx catalyst regenerator that regenerates the NOx catalyst 41 while raising the temperature of the NOx catalyst 41, and HC controller that decides whether the amount of adsorbed HC that is adsorbed by the HC adsorbent 43 is equal to or more than a preset reference amount and, when the amount of adsorbed HC is decided to be equal to or more than the reference amount, raises the temperature of the first purifying catalyst 148.