Abstract: In an internal combustion engine, inside an engine exhaust passage, a hydrocarbon feed valve (15) and an exhaust purification catalyst (13) are arranged. The carrier (50) of the exhaust purification catalyst (13) is formed from a crystallized composite oxide of aluminum and an alkali earth metal. On this carrier (50), precious metal catalysts (51, 52) are carried. The concentration of hydrocarbons which flow into the exhaust purification catalyst (13) is made to vibrate by within a predetermined range of amplitude of a 200 ppm or more and within a predetermined range of period of 5 second or less, whereby the NOx which is contained in exhaust gas is reduced at the exhaust purification catalyst (13).

Abstract: In an internal combustion engine, inside of an engine exhaust passage, a hydrocarbon feed valve (15) and an exhaust purification catalyst (13) are arranged. The exhaust purification catalyst (13) is comprised of a mixture of a first catalyst in which platinum (51) and a basic layer (52) are carried on alumina (50) and a second catalyst in which rhodium (56) is carried on zirconia (55). The concentration of hydrocarbons which flow into the exhaust purification catalyst (13) is made to vibrate by within a predetermined range of amplitude of a 200 ppm or more and within a predetermined range of period of 5 second or less, whereby the NOx which is contained in exhaust gas is reduced at the exhaust purification catalyst (13).

Abstract: In an internal combustion engine, inside of an engine exhaust passage, a hydrocarbon feed valve (15) and an exhaust purification catalyst (13) are arranged. The exhaust purification catalyst (13) is comprised of a mixture of a first catalyst in which platinum (51) and a basic layer (52) are carried on alumina (50) and a second catalyst in which rhodium (56) is carried on zirconia (55). The concentration of hydrocarbons which flow into the exhaust purification catalyst (13) is made to vibrate by within a predetermined range of amplitude of a 200 ppm or more and within a predetermined range of period of 5 second or less, whereby the NOx which is contained in exhaust gas is reduced at the exhaust purification catalyst (13).

Abstract: In an internal combustion engine, inside an engine exhaust passage, a hydrocarbon feed valve (15) and an exhaust purification catalyst (13) are arranged. The carrier (50) of the exhaust purification catalyst (13) is formed from a crystallized composite oxide of aluminum and an alkali earth metal. On this carrier (50), precious metal catalysts (51, 52) are carried. The concentration of hydrocarbons which flow into the exhaust purification catalyst (13) is made to vibrate by within a predetermined range of amplitude of a 200 ppm or more and within a predetermined range of period of 5 second or less, whereby the NOx which is contained in exhaust gas is reduced at the exhaust purification catalyst (13).

Abstract: An exhaust gas control apparatus for an internal combustion engine includes a NOx adsorbent that is provided in an exhaust passage of an internal combustion engine, and that adsorbs nitrogen monoxide; an active oxygen supply device that supplies active oxygen to an area upstream of the NOx adsorbent; and a control portion that performs a first control that does not cause the active oxygen supply device to supply the active oxygen while exhaust gas flows to the NOx adsorbent at a time of cold start of the internal combustion engine, whereby the nitrogen monoxide is adsorbed by the NOx adsorbent, wherein the control portion performs a second control that causes the active oxygen supply device to supply the active oxygen after the first control is finished, whereby the nitrogen monoxide adsorbed by the NOx adsorbent is converted to a nitrate or a nitrate ion on the NOx adsorbent.