A multi-stage mixer includes a multi-stage mixer inlet, a multi-stage mixer outlet, a first flow device, and a second flow device. The multi-stage mixer inlet is configured to receive exhaust gas. The multi-stage mixer outlet is configured to provide the exhaust gas to a catalyst. The first flow device is configured to receive the exhaust gas from the multi-stage mixer inlet and to receive reductant such that the reductant is partially mixed with the exhaust gas within the first flow device. The first flow device includes a plurality of main vanes and a plurality of main vane apertures. The plurality of main vane apertures is interspaced between the plurality of main vanes. The plurality of main vane apertures is configured to receive the exhaust gas and to cooperate with the plurality of main vanes to provide the exhaust gas from the first flow device with a swirl flow.

A multi-stage mixer includes a multi-stage mixer inlet, a multi-stage mixer outlet, a first flow device, and a second flow device. The multi-stage mixer inlet is configured to receive exhaust gas. The multi-stage mixer outlet is configured to provide the exhaust gas to a catalyst. The first flow device is configured to receive the exhaust gas from the multi-stage mixer inlet and to receive reductant such that the reductant is partially mixed with the exhaust gas within the first flow device. The first flow device includes a plurality of main vanes and a plurality of main vane apertures. The plurality of main vane apertures is interspaced between the plurality of main vanes. The plurality of main vane apertures is configured to receive the exhaust gas and to cooperate with the plurality of main vanes to provide the exhaust gas from the first flow device with a swirl flow.

A method for exhaust gas aftertreatment is provided, the method comprising: a) providing a nitrogen oxide-containing raw exhaust gas, b) introducing the nitrogen oxide-containing raw exhaust gas into a catalytic evaporator (1), c) introducing a urea solution and a fuel into the catalytic evaporator (1), as a result of which a reducing agent is obtained, and d) supplying the reducing agent to an exhaust gas aftertreatment system (8). Alternatively or in addition, a device for producing a reducing agent may be provided, a reducing agent produced with same, and the use of these objects.

A method for exhaust gas aftertreatment is provided, the method comprising: a) providing a nitrogen oxide-containing raw exhaust gas, b) introducing the nitrogen oxide-containing raw exhaust gas into a catalytic evaporator (1), c) introducing a urea solution and a fuel into the catalytic evaporator (1), as a result of which a reducing agent is obtained, and d) supplying the reducing agent to an exhaust gas aftertreatment system (8). Alternatively or in addition, a device for producing a reducing agent may be provided, a reducing agent produced with same, and the use of these objects.

A process for detecting reductant deposits includes accessing data indicative of signal output from a radiofrequency sensor positioned proximate a decomposition reactor tube; comparing the data indicative of signal output from the radiofrequency sensor to a deposit formation threshold; and activating a deposit mitigation process responsive to the data indicative of signal output from the radiofrequency sensor exceeding the deposit formation threshold.

A urea solution injection device includes an exhaust pipe for discharging exhaust gas generated in a combustion chamber to the exterior; an injector is installed and pierces into the exhaust pipe to inject urea solution into the exhaust gas flowing in the exhaust pipe. A catalyst is disposed at a position after the injector when viewed in a flow direction of the exhaust gas and the exhaust gas is discharged to the exterior to decompose the exhaust gas mixed with the urea solution. A urea solution mixer is provided at an end of the injector and installed and pierces into the exhaust pipe. Accordingly the urea solution injected from the injector is dispersed therein. An installation unit provides for the urea solution mixer to be installed in the exhaust pipe and pierces into the exhaust pipe.

A decomposition tube for an exhaust treatment system includes a housing with a housing wall that defines an exhaust flow path for exhaust; a reductant delivery mechanism coupled to the housing and having a nozzle configured to deliver a spray of reductant into the exhaust flow path; and a mesh device with a mounting element mounted on the housing wall and a mesh basket secured to the mounting element proximate to the nozzle to enclose and intercept the spray such that effectively all of the reductant passes through the mesh basket and into the exhaust flow path prior to impinging on the housing wall.

An exhaust gas purification system for lowering the content of impurities in a lean exhaust gas of an internal combustion engine comprising, a feeding device that feeds ammonia or a compound decomposable to ammonia into an exhaust gas stream containing nitrogen oxides; a selective catalytic reduction catalyst comprising vanadium (V-SCR catalyst) which catalyzes the nitrogen oxides with ammonia in a temperature range of about 150° C. to about 400° C. and at an NO.sub.2/NO.sub.x ratio of about 0.3 to about 0.9; and a downstream system comprising a diesel oxidation catalyst.

A reductant injecting device includes: a honeycomb structure comprising: a pillar shaped honeycomb structure portion having a partition wall that defines a plurality of cells each extending from a fluid inflow end face to a fluid outflow end face; and at least one pair of electrode portions arranged on a side surface of the honeycomb structure portion; an inner cylinder being configured to house the honeycomb structure; a urea sprayer arranged at one end of the inner cylinder; and an outer cylinder arranged on an outer peripheral side of the inner cylinder, the outer cylinder being spaced apart from the inner cylinder. A flow path through which the carrier gas passes is formed between the inner cylinder and the outer cylinder.

An object of the present disclosure is to provide an exhaust gas purification catalyst demonstrating superior storage of NOx contained in exhaust gas.

The exhaust gas purification catalyst of the present disclosure has a substrate, a first catalyst layer containing a catalytic metal for NOx reduction and a NOx storage material and formed on the substrate, and a second catalyst layer containing a catalytic metal for NOx oxidation and formed on the first catalyst layer. In the exhaust gas purification catalyst of the present disclosure, the value obtained by dividing the volume of all large pores having a pore volume of 1000 μm.sup.3 or more by the total volume of all medium pores of having a pore volume of 10 μm.sup.3 to 1000 μm.sup.3 in the second catalyst layer is 2.44 or less.