The invention relates to a wall-flow filter as a particle filter with catalytically active coatings in the channels which are closed in a gas-tight manner at the opposing closed ends of the channels A at the first end, wherein the inlet region of the filter is additionally supplied with a dry powder-gas aerosol which contains metal compounds with a high melting point (such as the metal oxides Al2O3, SiO2, FeO2, TiO2, ZnO2, etc. for example) and which is to simultaneously improve the catalytic activity and the degree of filtration efficiency with respect to the exhaust gas back-pressure.

The invention relates to a wall-flow filter as a particle filter with catalytically active coatings in the channels which are closed in a gas-tight manner at the opposing closed ends of the channels A at the first end, wherein the inlet region of the filter is additionally supplied with a dry powder-gas aerosol which contains metal compounds with a high melting point (such as the metal oxides Al2O3, SiO2, FeO2, TiO2, ZnO2, etc. for example) and which is to simultaneously improve the catalytic activity and the degree of filtration efficiency with respect to the exhaust gas back-pressure.

An object of the present invention is to provide an exhaust gas purification catalyst including a wall-flow substrate and a catalyst layer, and having an improved exhaust gas purification performance, and, in order to achieve such an object, the present invention provides an exhaust gas purification catalyst including: a wall-flow substrate, first catalyst layers; and second catalyst layers; wherein the first catalyst layers and the second catalyst layers satisfy the following expressions (1) to (3):

L1<L2  (1)

T1<T2  (2)

WC1>WC2  (3)

wherein L1 represents the length of the first catalyst layers, L2 represents the length of the second catalyst layers, T1 represents the thickness of the rising portions of the first catalyst layers, T2 represents the thickness of the rising portions of the second catalyst layers, WC1 represents the mass of the first catalyst layers per unit volume of the portion of the substrate provided with the first catalyst layers, and WC2 represents the mass of the second catalyst layers per unit volume of the portion of the substrate provided with the second catalyst layers.

An exhaust gas purification device including: a first case communicating with an exhaust manifold of an engine and internally including a first exhaust gas purification body for removing a carbon compound; and a second case communicating with an exhaust outlet of the first case and internally including second exhaust gas purification bodies for removing a nitrogen compound. The first case and the second case are arranged above the engine and in an L-shape to respectively extend along two side surfaces of the engine, the two side surfaces being adjacent to each other.

An exhaust gas purification device including: a first case communicating with an exhaust manifold of an engine and internally including a first exhaust gas purification body for removing a carbon compound; and a second case communicating with an exhaust outlet of the first case and internally including second exhaust gas purification bodies for removing a nitrogen compound. The first case and the second case are arranged above the engine and in an L-shape to respectively extend along two side surfaces of the engine, the two side surfaces being adjacent to each other.

The present invention relates to a particulate filter which comprises a wall flow filter of length L and two different catalytically active coatings Y and Z, wherein the wall flow filter comprises channels E and A that extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls which form the surfaces O.sub.E and O.sub.A, respectively, and wherein the channels E are closed at the second end and the channels A are closed at the first end. The invention is characterized in that the coating Y is located in the channels E on the surfaces O.sub.E and the coating Z is located in the channels A on the surfaces O.sub.A.

A method for controlling urea injection in an exhaust aftertreatment system includes injecting urea at a flow rate upstream of the first catalytic reduction device; measuring a level of nitrogen oxides downstream of the first catalytic reduction device and upstream of the second catalytic reduction device; controlling the flow rate of the urea injection until the measured level of nitrogen oxides fulfils a predetermined condition; if the measured level of nitrogen oxides is decreasing in response to reducing the flow rate of the urea injection, reducing the flow rate of the urea injection, and controlling a flow rate of urea injection using the second urea injector upstream of the second catalytic reduction device according to the measured level of nitrogen oxides downstream of the first catalytic reduction device and upstream of the second catalytic reduction device.

A method for controlling urea injection in an exhaust aftertreatment system includes injecting urea at a flow rate upstream of the first catalytic reduction device; measuring a level of nitrogen oxides downstream of the first catalytic reduction device and upstream of the second catalytic reduction device; controlling the flow rate of the urea injection until the measured level of nitrogen oxides fulfils a predetermined condition; if the measured level of nitrogen oxides is decreasing in response to reducing the flow rate of the urea injection, reducing the flow rate of the urea injection, and controlling a flow rate of urea injection using the second urea injector upstream of the second catalytic reduction device according to the measured level of nitrogen oxides downstream of the first catalytic reduction device and upstream of the second catalytic reduction device.

An exhaust gas/reactant mixing arrangement for an exhaust system of an internal combustion engine mixes exhaust gas and reactant. The mixing arrangement includes an exhaust gas guide housing defining a longitudinal axis and having a housing wall. An exhaust gas duct is surrounded by the housing wall and exhaust gas can flow therethrough. A mixing zone has a mixing chamber formed between an upstream end wall and a downstream end wall and a reactant dispensing arrangement is supported on the exhaust gas guide housing. The reactant dispensing arrangement dispenses reactant into the mixing chamber along a reactant dispensing line in a dispensing direction. A mixture flow path leads from an inflow opening to an outflow opening and is formed in the mixing chamber. The mixture flow path has two flow deflection regions, which follow one another in a mixture flow direction and have mutually opposite flow deflection directions.

An exhaust gas/reactant mixing arrangement for an exhaust system of an internal combustion engine mixes exhaust gas and reactant. The mixing arrangement includes an exhaust gas guide housing defining a longitudinal axis and having a housing wall. An exhaust gas duct is surrounded by the housing wall and exhaust gas can flow therethrough. A mixing zone has a mixing chamber formed between an upstream end wall and a downstream end wall and a reactant dispensing arrangement is supported on the exhaust gas guide housing. The reactant dispensing arrangement dispenses reactant into the mixing chamber along a reactant dispensing line in a dispensing direction. A mixture flow path leads from an inflow opening to an outflow opening and is formed in the mixing chamber. The mixture flow path has two flow deflection regions, which follow one another in a mixture flow direction and have mutually opposite flow deflection directions.