Method for purifying exhaust gas of gasoline engine

PROBLEM TO BE SOLVED: To remove NOx even from exhaust gas changed in compsn. and temp. by an operation condition by purifying the exhaust gas of a fuel direct jet type gasoline engine by an exhaust gas purifying catalyst using noble metal and/or transition metal. SOLUTION: A purifying catalyst 12 is obtained by a method wherein noble metal and/or transition metal is supported on or mixed with a powder of fire- resistant inorg. oxide becoming a porous carrier such as alumina and the resulting compsn. is further applied to a monolithic carrier to be held thereto. An oxygen sensor 11 measuring the consn. of oxygen in exhaust gas is provided in the passage of an exhaust port 6 and the purifying catalyst 12 removing a harmful component in exhaust gas is provided on the downstream side of the sensor 11. By this constitution, even if exhaust gas is changed to a first exhaust gas state and a low temp. second exhaust gas state in an oxidizing atmosphere by an operation condition like the exhaust gas of a fuel direct jet type gasoline engine, this exhaust gas is simply purified. COPYRIGHT: (C)1997,JPO