| abstract |
A method for purifying exhaust gas of an internal combustion engine, including chemically reducing NOx that is contained in the exhaust gas when a concentration of hydrocarbons flowing into an exhaust purification catalyst is made to vibrate within a predetermined range of amplitude and within a predetermined range of period, wherein, during the chemical reduction, the NOx contained in the exhaust gas is reacted with reformed hydrocarbons to produce a reducing intermediate containing nitrogen and hydrocarbons, a reducing action of the reducing intermediate chemically reduces the NOx, and the NOx is chemically reduced without storing nitrates or with storing a fine amount of the nitrates in a basic layer of the exhaust purification catalyst. |