Patent ID: 9404406
Filing Date: 2016-08-02
CPC Classification: B01D,F01N,F02B,F02D,F02M,Y02T

Claim Text:
1. A catalyst for purifying exhaust gas under the conditions of exhaust gas produced in gasoline engines of a fuel-direct-injection type, the catalyst comprising (i) platinum or palladium and (ii) cerium carried by or mixed with a fire-resistant inorganic oxide, the fire-resistant inorganic oxide having a BET surface area in a range of 50 to 200 m the catalyst containing the platinum or palladium in a range of 0.01 to 50 g/liter with respect to a catalyst volume, the fire-resistant inorganic oxide being at least one kind of α-alumina, γ-alumina, δ-alumina, η-alumina, active alumina of θ-alumina, titania, zirconia, and composite oxides thereof, wherein the catalyst purifies exhaust gases produced in gasoline engines of a fuel-direct-injection the under (i) a first exhaust gas state in which an air-fuel ratio is in a range of 13 to 15, and an exhaust-gas temperature is in a range of 350 to 800° C., and purifies an exhaust gas produced in gasoline engines of a fuel-direct-injection type under (ii) a second exhaust gas state in which the air-fuel ratio exceeds an air-fuel ratio of 15, and the exhaust-gas temperature is in a range of 200 to 350° C.