EXHAUST GAS PURIFICATION DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

In an internal combustion engine, inside of an engine exhaust passage, an NO x adsorption part and an NO x purification part are arranged. The NO x purification part has the property of reducing NO x which is contained in exhaust gas if the concentration of hydrocarbons is made to vibrate by within a predetermined range of amplitude and within a predetermined range of period. When NO x is to be desorbed from the NO x adsorption part (at step 203), the current NO x which is contained in the exhaust gas and the NO x which is desorbed from the NO x adsorption part are reduced by making the concentration of hydrocarbons of the NO x purification part vibrate by the amplitude and period which are set for the current engine operating state, at least of which (”T·k) has been corrected so that the amount of hydrocarbons becomes greater (step 205).