Hydrocarbon adsorbent for exhaust gas cleaning, exhaust gas cleaning catalyst and exhaust gas cleaning device

摘要

In order to adsorb effectively various kind of hydrocarbons each having a different size 6, a zeolite having a larger pore 8, a zeolite having a smaller pore 6 and a zeolite having an in-between pores 7 are present together very closely located very closely to one another by means of, for example, physically mixing them.