Abstract:
Provided is a catalyst composition for treating exhaust gas comprising a blend of a first component and second component, wherein the first component is an aluminosilicate or ferrosilicate molecular sieve component wherein the molecular sieve is in H+ form, and the second component is a vanadium oxide supported on a metal oxide support selected from alumina, titania, zirconia, ceria, silica, and combinations thereof. Also provided are methods, systems, and catalytic articles incorporating or utilizing such catalyst blends.
Abstract:
The invention relates to a catalyst comprising at least two catalytically active layers A and B, wherein A contains a carrier oxide and the components A1 and A2, and B contains a carrier oxide and the components B1, B2, and B3, wherein A1, A2, and B1 to B3 are defined as disclosed in claim 1. The proportion of component A1 in layer A is thereby greater than the proportion of component B1 in layer B, wherein the proportion of layer A with respect to the total weight of layers A and B is greater than the proportion of layer B. The invention further relates to a method for reducing nitrogen oxides in exhaust gases of lean-burn internal combustion engines, and to an exhaust gas cleaning system.
Abstract:
The present invention concerns a catalytic converter for treating exhaust from a combustion engine (1). The catalytic converter (5) comprises wall elements (5b) that form a plurality of longitudinal channels (5a) in the catalytic converter for receiving exhaust. The wall elements (5b) comprise a first outer layer (5b1) that presents an external surface of the longitudinal channels (5a) and a second inner layer (5b2) that is arranged internally around the first layer (5b1). The first layer comprises a first active catalytic material that promotes a catalytic reaction between nitrogen oxide and ammonia. The second layer (5b2) comprises a material that has the ability to store nitrogen oxide and a second active catalytic material that has a greater ability to promote the oxidation of nitrogen monoxide into nitrogen dioxide than the first catalytic material.
Abstract:
A deterioration diagnosis device for an exhaust gas purification apparatus which performs inducement processing when the internal combustion engine (1) is operated at a lean air fuel ratio, measures, by means of air fuel ratio sensors, the air fuel ratio of exhaust gas flowing into the SCR catalyst (6) and the air fuel ratio of exhaust gas flowing out from the SCR catalyst (6) during a period while the inducement processing is performed, and diagnoses deterioration of the SCR catalyst (6) based on a difference between the measured values of these sensors, wherein an amount of hydrogen produced by each of a three-way catalyst and an NSR catalyst (5) is estimated based on the deterioration degree thereof, and an air fuel ratio of exhaust gas discharged from the internal combustion engine is feedback-controlled so that the air fuel ratio of the exhaust gas flowing into one of the three-way catalyst and the NSR catalyst (5) in which the hydrogen production amount thus estimated is larger than that in the other becomes a target value.
Abstract:
The present invention relates to a diagnostic device which performs highly accurate diagnosis of the deterioration of a DOC. The diagnostic device includes: a DOC (15) for oxidizing HC and NO in an exhaust gas; an SCR catalyst (22) for reducing and purifying NOx contained in the exhaust gas; a NOx purification rate calculation unit (41) which calculates, based on NOx values at upstream and downstream sides of the SCR catalyst (22), a low temperature NOx purification rate and a high temperature NOx purification rate; a HC heat generation rate calculation unit (42) which calculates an HC purification rate based on at least the difference between the exhaust gas heat quantities at upstream and downstream sides of the DOC (15); and a deterioration determination unit (45) which determines the deterioration in the NO 2 producing capability of the DOC (15) based on the calculated low temperature NOx purification rate, the calculated high temperature NOx purification rate, and the calculated HC purification rate.
Abstract:
An internal combustion engine in which a hydrocarbon feed valve, exhaust purification catalyst, and NOX selective reduction catalyst are arranged in an engine exhaust passage. A first NOX removal method which injects hydrocarbons from the hydrocarbon feed valve within a predetermined range of period and uses the reducing intermediate which is generated due to this so as to reduce the NOX contained in the exhaust gas and a second NOX removal method which makes the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst rich with a period longer than this predetermined range are used. When the first NOX removal method should be used and the amount of adsorbed ammonia at the NOX selective reduction catalyst is large, use of the first NOX removal method is stopped.