The present disclosure relates to a method for forming a catalyst article comprising: (a) forming a plastic mixture having a solids content of greater than 50% by weight by mixing together a crystalline small pore or medium pore molecular sieve in an H.sup.+ or NH.sub.4.sup.+ form, an insoluble active metal precursor, an inorganic matrix component, an organic auxiliary agent, an aqueous solvent and optionally inorganic fibres; (b) moulding the plastic mixture into a shaped article; and (c) calcining the shaped article to form a solid catalyst body. The present disclosure further relates to a catalyst article, particularly a catalyst article which is suitable for use in the selective catalytic reduction of nitrogen oxides, and to an exhaust system.

A selective catalytic reduction (SCR) system is provided for treating exhaust gas in an exhaust passage. The system comprises a hydrolysis catalyst located in the exhaust passage, and a diesel exhaust fluid (DEF) dosing unit configured to inject DEF onto the hydrolysis catalyst. A SCR catalyst is located in the passage downstream of the hydrolysis catalyst, and a controller controls DEF dosing by the dosing unit. The controller is configured to control the DEF dosing unit such that the DEF is injected at a modulated frequency of less than or equal to 1 Hertz. A method of treating exhaust gas in an exhaust passage using an SCR system is also provided.

The invention relates to a mixing device (1) for integration into an exhaust pipe (4.1, 4.2) of an internal combustion engine and for mixing an exhaust gas stream (T), which device is formed from a housing (2) having a tubular wall (2.1) and a mid-axis (2.2) that can be aligned parallel to the exhaust pipe (4.1, 4.2) and from an intermediate wall (3) which is aligned transversely with respect to the mid-axis (2.2), wherein the intermediate wall (3) divides the housing (2) and has an inflow side (3.1) and an outflow side (3.2), wherein at least one inflow opening (E1) is provided in the intermediate wall (3), via which the exhaust gas stream (T) can at least partly flow from the inflow side (3.1) of the intermediate wall (3) to the opposite outflow side (3.2) of the intermediate wall (3), wherein the at least one inflow opening (E1) is placed eccentrically with respect to the mid-axis (2.2) and is brought close to a wall section (W1) of the tubular wall (2.1), wherein a flow guide element (S2) having a longitudinal axis (L2) is provided on the outflow side (3.2), which at least partly bounds a mixing chamber (2.3) with the intermediate wall (3) and by means of which an at least partial deflection of the exhaust gas stream (T) in a radial direction in relation to the mid-axis (2.2) can be effected, wherein the flow guide element (S2) has at least two outflow openings (A1, A2) and, by means of the flow guide element (S2), the exhaust gas stream (T) coming from the inflow opening (E1) can be guided to the at least two outflow openings (A1, A2), wherein the outflow openings (A1, A2) are placed eccentrically with respect to the mid-axis (2.2) and brought close to a common wall section (W2) of the tubular wall (2.1), wherein the wall section (W2) is arranged opposite to the wall section (W1) with respect to the mid-axis (2.2), and wherein the outflow openings (A1, A2) are arranged on opposite sides of the flow guide element (S2) with respect to the longitudinal axis (L1, L2), wherein, with respect to the mid-axis (2.2), the first partial stream (T3) can be can at least partly guided in the anticlockwise direction and a second partial stream (T4) can at least partly be guided in the clockwise direction out of the outflow openings (A1, A2).

A flexible resistor including a support made of electrically insulating material; at least one track made of an electrically conductive material incorporated in the support, and configured to be connected to an electric energy source; a foil made of electrically conductive material, having a surface fixed to a first face of the support, and a plurality of wings defined by foil portions cut and folded transversally to the surface.

The present disclosure relates to a method for forming a catalyst article comprising: (a) forming a plastic mixture having a solids content of greater than 50% by weight by mixing together a crystalline small pore or medium pore molecular sieve in an H.sup.+ or NH.sub.4.sup.+ form, an insoluble active metal precursor, an inorganic matrix component, an organic auxiliary agent, an aqueous solvent and optionally inorganic fibres; (b) moulding the plastic mixture into a shaped article; and (c) calcining the shaped article to form a solid catalyst body. The present disclosure further relates to a catalyst article, particularly a catalyst article which is suitable for use in the selective catalytic reduction of nitrogen oxides, and to an exhaust system.

A bottoming cycle power system includes a turbo-expander operable to rotate a turbo-crankshaft as a flow of exhaust gas from a combustion process passes through the turbo-expander. A turbo-compressor is operable to compress the flow of exhaust gas after the exhaust gas passes through the turbo-expander. An open cycle absorption chiller system includes an absorber section operable to receive the flow of exhaust gas from the turbo-expander and to mix the flow of exhaust gas with a first refrigerant solution within the absorber section. The first refrigerant solution is operable to absorb water from the exhaust gas as the exhaust gas passes through the first refrigerant solution. The absorber section is operable to route the flow of exhaust gas to the turbo-compressor after the flow of exhaust gas has passed through the first refrigerant solution.

Various embodiments include methods for determining the efficiency of an SCR catalytic converter in a system including a nitrogen oxide sensor, and a metering device for a reducing agent arranged in an exhaust-gas duct, and an exhaust recirculation line with a recirculation valve disposed downstream of the SCR catalytic converter and feeding an intake region of the engine. The methods comprise: setting or identifying a quasi-steady-state operating state and an associated recirculation rate; adding a first quantity of reducing agent using the metering device; measuring a resulting first nitrogen oxide value using the sensor; adding a further predefined quantity, different from the first quantity; measuring the resulting nitrogen oxide values using the sensor; and determining the efficiency of the SCR catalytic converter based at least in part on the associated exhaust-gas recirculation rate and the measured nitrogen oxide values.

A mixer is provided for mixing exhaust gas (A) flowing in an exhaust gas-carrying duct (14) of an internal combustion engine with reactant injected into the exhaust gas-carrying duct (14). The mixer includes a mixing body (22) with a reactant-receiving duct (34), an exhaust gas inlet opening device (54) with a plurality of exhaust gas inlet openings (56) leading to the reactant-receiving duct (34), and at least one releasing duct (40, 42) leading away from the reactant-receiving duct (34) with a releasing duct opening (48, 50) for releasing a reactant/exhaust gas mixture from the mixer body (22). An electrically energizable heater (68) is provided at the mixer body (22).

An after-treatment exhaust gas mixer for mixing the exhaust gas with a reducing agent, such as a diesel exhaust fluid for selective catalyst reduction, comprises a mixing chamber through which the exhaust gas circulates, from an inlet to an outlet, and a reducing agent sprayer, able to spray a reducing agent into the mixing chamber. The mixing chamber comprises a pipe that is rectilinear along an axis and the sprayer is positioned in the upstream part of the rectilinear pipe and oriented so as to spray in the downstream direction substantially parallel to the axis.

An exhaust gas purification device includes a selective catalytic reduction (SCR) device arranged in a downstream exhaust flow path, and a mixer arranged upstream of the selective catalytic reduction device and including a helical flow path that helically guides the flow of exhaust gas from an internal combustion engine. In the exhaust gas purification device, the mixer includes a casing, an injector, and a partition plate. The casing has an upstream opening and a downstream opening and is provided with the helical flow path therein. The injector is arranged in the helical flow path to add a reducing agent to the helical flow path. The partition plate is continuous from the upstream opening to the downstream opening. The partition plate is arranged to divide the inner space of the casing into an upstream side and a downstream side, and defines the helical flow path.