Exhaust gas treatment system, method of treating exhaust gas stream, and associated control system

Abstract

An exhaust gas treatment system (250, 350) arranged for treating an exhaust gas stream (203, 303) resulting from combustion in a combustion engine (201, 301) is presented. The exhaust gas treatment system (250, 350) comprises at least one fibrous structure (280a-d, 380a-d) arranged downstream of the evaporation arrangement to interact with particles in the exhaust gas flow (203, 303). These particles are produced by one or more of a supply of the additive into the exhaust gas stream and a transition of the additive as it flows through the exhaust gas treatment system. The at least one fibrous structure (280a-d, 380a-d) has a fiber volume ratio F / V in the range of 40% to 90% such that:-the particles interact with the at least one fibrous structure (280a-d, 380a-d), thereby being at least partially captured and removed from the exhaust gas stream (203, 303); and-at least partially avoiding the accumulation of soot and ash resulting from the combustion, which accumulation will affect the interaction of the at least one fibrous structure (280a-d, 380a-d) with the particles.

Description

Technical Field

[0001] The present invention relates to an exhaust gas treatment system, a method for treating an exhaust gas stream, and a control system for controlling the exhaust gas treatment system to perform the method.

[0002] The present invention also relates to a computer program and a computer program product for implementing the method according to the present invention. Background Art

[0003] The following background art description constitutes a description of the background art of the present invention and thus does not necessarily have to constitute prior art.

[0004] In connection with the increasing concern of governments about pollution and air quality, mainly in urban areas, emission standards and regulations regarding emissions from combustion engines have been drafted in many jurisdictions.

[0005] Such emission standards typically consist of requirements defining acceptable limits for exhaust emissions from, for example, combustion engines in vehicles. For example, for most types of vehicles, the emissions of nitrogen oxides NO x 、hydrocarbons C x H y 、carbon monoxide CO and particulate matter PM are typically regulated by such standards. Vehicles equipped with combustion engines typically produce such emissions to varying degrees. In this document, the application of the present invention in vehicles, i.e., for internal combustion engines, will be mainly described. However, the present invention can be used in substantially all applications using combustion engines, such as in ships like boats or in aircraft / helicopters, where regulations and standards for such applications limit the emissions of combustion engines.

[0006] To comply with these emission standards, the exhaust gas caused by the combustion of the combustion engine is treated (purified).

[0007] Common ways of treating the exhaust gas from a combustion engine include a so-called catalytic purification process, whereby a vehicle equipped with a combustion engine typically includes at least one catalyst. There are different types of catalysts, and different corresponding types can be suitable, depending on, for example, the combustion concept, combustion strategy, and / or fuel type used in the vehicle, and / or the type of compounds in the exhaust gas stream to be purified. Regarding at least nitrous gases (nitric oxide, nitrogen dioxide), hereinafter referred to as nitrogen oxides NO x ,a vehicle typically includes a catalyst, where an additive is supplied to the exhaust gas stream generated by the combustion in the combustion engine in order to mainly reduce the nitrogen oxides NO x to nitrogen and water vapor. This will be described in more detail below.

[0008] An SCR (selective catalytic reduction) catalyst is a common type of catalyst used for this type of reduction, mainly for heavy-duty trucks. The SCR catalyst typically uses ammonia NH3 or a composition from which ammonia can be generated / formed as an additive to reduce nitrogen oxides NO in the exhaust gas. x The amount of. The additive, such as urea, is injected into the exhaust gas stream generated by the combustion engine upstream of the catalyst. The additive added to the catalyst is adsorbed (stored) in the catalyst in the form of ammonia NH3, such that a redox reaction can occur between the nitrogen oxides NO in the exhaust gas x and the ammonia NH3 available via the additive. Summary of the Invention

[0009] When the additive is injected into the exhaust gas stream, i.e., when the additive is supplied to the exhaust gas treatment system, small particles may be generated upon injection of the additive. Additionally, when the injected additive travels with the exhaust gas stream through the components of the exhaust gas treatment system, more small particles may be generated from the additive due to the treatment performed by the components of the exhaust gas treatment system on the exhaust gas stream. Thus, these additive-based small particles may be generated by the additive upon injection and / or by various transformations of the additive when flowing through the exhaust gas treatment system. Thus, the particles may include urea and / or urea-based polymeric by-products, depending on where they are generated in the exhaust gas treatment system.

[0010] These additive-based small particles may, for example, have a diameter in the range of 10 to 23 nm and may flow through the entire exhaust gas treatment system with the exhaust gas stream and be discharged at the exhaust pipe. Thus, at least a portion of these additive-based particles may, for example, pass through each component of the exhaust gas treatment system, also through the SCR catalyst, due to their small size and may be discharged into the environment as emissions. The additive-based particles may also include combustion-based particles, i.e., particles generated during combustion in the combustion engine. Thus, due to the interaction and / or mixing with the particles from combustion, the small-sized particles may subsequently include a mixture of additive-based particles and soot and / or ash. If these small particles are discharged, they may have health effects.

[0011] An object of the present invention is to at least partially prevent the emission of these additive-based small particles into the environment.

[0012] The object is achieved by the above-mentioned exhaust gas treatment system, which is arranged to treat the exhaust gas stream generated by combustion in a combustion engine, and the exhaust gas treatment system comprises:

[0013] - a particulate filter, which is arranged to capture the soot and ash generated by the combustion;

[0014] - A metering arrangement, which is arranged downstream of the particulate filter for supplying an additive to the exhaust gas stream, and the additive is mixed with the exhaust gas stream by an evaporation arrangement arranged at the metering arrangement;

[0015] - A reduction catalyst arrangement, which is arranged downstream of the metering arrangement for reducing nitrogen oxides NO in the exhaust gas stream by utilizing the supplied additive x ;

[0016] and

[0017] - At least one fibrous structure, which is arranged downstream of the evaporation arrangement for interacting with the particles in the exhaust gas stream, the particles being generated by one or more of the supply of the additive to the exhaust gas stream and the transformation of the additive during the flow through the exhaust gas treatment system, wherein the at least one fibrous structure has a fiber volume ratio F / V in the range of 40% to 90%, such that:

[0018] -- The particles interact with the at least one fibrous structure, thereby being at least partially captured and removed from the exhaust gas stream; and

[0019] -- The accumulation of soot and ash generated by the combustion is at least partially avoided, and such accumulation would affect the interaction between the at least one fibrous structure and the particles.

[0020] Therefore, before the exhaust gas stream is discharged from the exhaust pipe, the additive fine particles are at least partially removed from the exhaust gas stream. Thus, these fine particles, which may have a diameter in the range of 10 to 23 nm, are dissolved by interacting with at least one fibrous structure and are at least partially prevented from leaving the exhaust pipe. Such a material structure having the at least one fibrous structure promotes the retention of additive-based particles. The soot and ash from combustion can only accumulate to a low level, so that the interaction performance of the at least one fibrous structure is not reduced.

[0021] A fiber volume ratio F / V in the range of 40% to 90% enables the capture and removal of the above-mentioned additive-based fine particles, but at least partially avoids the accumulation of soot and ash. Therefore, a fiber volume ratio F / V in the range of 40% to 90% defines at least one fibrous structure, such that although the at least one fibrous structure provides poor filtration in the conventional sense for capturing large soot and ash particles, it unexpectedly effectively captures and removes additive-based fine particles.

[0022] At least one fibrous structure can be implemented at substantially any location in the exhaust gas treatment system, which enables a flexible implementation and does not affect the functionality of other components in the exhaust gas treatment system. In particular, since at least one fibrous structure is separated from the evaporation arrangement by its position downstream of the evaporation arrangement, it does not affect the functionality of the evaporation arrangement.

[0023] The exhaust gas treatment system according to the invention can meet the emission requirements in current and / or future emission standards.

[0024] According to an embodiment, the at least one fibrous structure is arranged at least 0.1 m downstream of the metering arrangement.

[0025] Thereby, the at least one fibrous structure is separated from the metering arrangement and thus also from the evaporation arrangement, such that it does not affect the injection of the additive into the exhaust gas stream. Thus, at least the fibrous structure is arranged by this placement to interact with the additive-based small particles and remove the additive-based small particles. However, the injected additive intended to be used by the catalyst in the system contacts the catalyst, such that an effective reduction of nitrogen oxides NO x is provided.

[0026] According to an embodiment, the at least one fibrous structure is included in the reduction catalyst arrangement.

[0027] By this position of the at least one fibrous structure integrated in the reduction catalyst arrangement, an effective removal of the particles is provided by a compact component solution.

[0028] According to an embodiment, the at least one fibrous structure is arranged downstream of the reduction catalyst arrangement.

[0029] Thus, the at least one fibrous structure does not affect the performance of the reduction catalyst arrangement.

[0030] According to an embodiment, the exhaust gas treatment system further includes a slip catalyst arrangement arranged downstream of the reduction catalyst arrangement for oxidizing additive residues in the exhaust gas stream, and the at least one fibrous structure is arranged downstream of the reduction catalyst arrangement and upstream of the slip catalyst arrangement.

[0031] At this position, an effective function of the at least one fibrous structure can be provided.

[0032] According to an embodiment, the exhaust gas treatment system further includes a slip catalyst arrangement arranged downstream of the reduction catalyst arrangement for oxidizing additive residues in the exhaust gas stream, and the at least one fibrous structure is included in the slip catalyst arrangement.

[0033] By integrating this position of the at least one fibrous structure in the slip catalyst, an effective removal of additive-based particles is provided by a compact component solution.

[0034] According to an embodiment, the exhaust gas treatment system further includes a slip catalyst arrangement disposed downstream of the reduction catalyst arrangement for oxidizing additive residues in the exhaust gas stream, and the at least one fibrous structure is disposed downstream of the slip catalyst arrangement.

[0035] At this position, an effective function of the at least one fibrous structure can be provided, namely, effective capture and removal of additive-based particles.

[0036] According to an embodiment, the reduction catalyst arrangement includes one or more of the following groups:

[0037] - at least one selective catalytic reduction catalyst;

[0038] - at least one slip catalyst.

[0039] Thereby, an effective removal of nitrogen oxides NO x can be provided.

[0040] According to an embodiment

[0041] - the at least one fibrous structure includes at least one section arranged to be heated by the exhaust gas stream flowing therethrough to an interaction temperature T I which is higher than the particle temperature T I at which the particles thermally dissolve; T P ; T I > T P ; and

[0042] - the at least one fibrous structure is arranged to interact with the particles such that the particles are at least partially in physical contact with the heated at least one section.

[0043] Thus, the additive-based particles are effectively dissolved by the at least one fibrous structure which is at least partially heated by the exhaust gas stream.

[0044] According to an embodiment, the interaction temperature T I is at least 150 °C.

[0045] When the interaction temperature T I reaches and / or exceeds 150 °C, the additive-based particles are effectively dissolved and thus removed from the exhaust gas stream. Thus, if the interaction temperature T I is initially below 150 °C, some particles may first accumulate in the at least one fibrous structure. Then, when the interaction temperature T IWhen reaching 150 °C, these accumulated particles dissolve.

[0046] According to an embodiment, the at least one fibrous structure at least partially comprises an inert material.

[0047] Thus, the additive-based particles are effectively thermally dissolved by heat herein. Additionally, the material structure of the at least one fibrous structure promotes the retention of the additive-based particles.

[0048] According to an embodiment, the inert material is one or more of the following groups:

[0049] - metallic materials; and

[0050] - non-metallic materials.

[0051] Thus, a variety of materials and / or material mixtures can be used in the at least one fibrous structure to remove the additive-based particles. Thereby, implementation flexibility is provided. In different embodiments, materials such as cordierite, silicon carbide, aluminum titanate, and / or polymer composites can be used.

[0052] According to an embodiment, the at least one fibrous structure at least partially comprises an active catalytic material.

[0053] Thus, the additive-based particles can be dissolved by using an active catalytic material such as noble metals, vanadium, iron (Fe), copper, titanium, tungsten, and / or aluminum, and the active catalytic material may also have other functions in the exhaust gas treatment system. Thereby, an effective solution that requires no additional space or occupies very little additional space is provided.

[0054] According to an embodiment, the material is coated on the at least one fibrous structure.

[0055] Thus, the material for removing the additive-based particles, which can be an inert or catalytically active material, can be coated on the at least one fibrous structure. The coating of the material can improve the efficiency of the at least one fibrous structure in capturing and dissolving the retained additive-based particles.

[0056] According to an embodiment, the at least one fibrous structure comprises a porous structure / configuration / construction / texture / composition / fabric / mesh / weave, which is arranged to allow the exhaust gas flow to pass therethrough.

[0057] Thereby, that is, through the porous structure / configuration / construction / texture / composition / fabric / mesh / weave, the additive-based particles effectively interact with the at least one fibrous structure, causing the particles to dissolve.

[0058] According to an embodiment,

[0059] - The at least one fibrous structure has a cross-sectional area A in inches 2 and a length L in inches; and

[0060] - The area-to-length ratio A / L of the at least one fibrous structure has a value of at least 17 inches and at most 150 inches in inches; 17 ≤ A / L ≤ 150 inches.

[0061] Within this range of the area-to-length ratio A / L, very small and effective fibrous structures are provided.

[0062] According to an embodiment, the additive includes one or more of the following groups:

[0063] - Ammonia, and

[0064] - Substances from which ammonia can be extracted and / or released.

[0065] Thereby, an effective reduction of nitrogen oxides NO x in the exhaust gas stream can be provided by the exhaust gas treatment system.

[0066] According to an embodiment, the particles include one or more of the following groups:

[0067] - Urea; and

[0068] - Urea-based polymerization by-products.

[0069] Thus, the additive-based particles are relatively unstable and can be dissolved by the at least one fibrous structure. Alternatively, the particles can be captured by the at least one fibrous structure.

[0070] According to an embodiment, the fiber volume ratio F / V of the at least one fibrous structure is in the range of 40% to 70%.

[0071] Thus, an interaction between the at least one fibrous structure and the additive-based particles is provided, which effectively dissolves the particles.

[0072] According to an embodiment, the exhaust gas treatment system includes:

[0073] - An upstream metering device arranged to supply the additive into the exhaust gas stream;

[0074] - An upstream reduction catalyst device arranged downstream of the upstream metering device for reducing nitrogen oxides NO x in the exhaust gas stream by utilizing the supplied additive;

[0075] - A particulate filter arranged downstream of the upstream reduction catalyst device to capture soot and ash generated by combustion;

[0076] - A metering arrangement, which is arranged as a downstream metering device downstream of the particulate filter, for supplying an additive into the exhaust gas stream, the additive being mixed with the exhaust gas stream by an evaporation arrangement arranged at the downstream metering device as a downstream evaporation arrangement;

[0077] - A reduction catalyst arrangement, which is arranged as a downstream reduction catalyst device downstream of the downstream metering device for reducing nitrogen oxides NO in the exhaust gas stream by utilizing the supplied additive x ;

[0078] and

[0079] - At least one fibrous structure, which is arranged downstream of the downstream evaporation arrangement.

[0080] The upstream and downstream reduction catalyst devices can be optimized separately, and taking into account the function of the entire exhaust gas treatment system, this can achieve a very effective overall purification of the exhaust gas. This separate optimization can also be used to reduce one or several of the volumes occupied by the upstream and downstream reduction catalyst devices, so as to obtain a compact exhaust gas treatment system.

[0081] In addition, the two additive metering devices in the system make it possible to adjust the amounts of the additives injected by the upstream and downstream metering devices separately. Therefore, by actively controlling the upstream metering and the downstream metering separately, the amount of the additive and / or the amount of additive-based particles at the downstream reduction catalyst arrangement can be controlled to be suitable for the effective reduction of nitrogen oxides NO x and / or to keep the additive-based particles at a reasonable level with respect to the permitted emission levels.

[0082] According to an embodiment, the upstream reduction catalyst device includes one or more of the following groups:

[0083] - An upstream selective catalytic reduction catalyst; and

[0084] - An upstream slip catalyst.

[0085] Thereby, a flexible exhaust gas treatment system is provided, which effectively reduces nitrogen oxides NO in the exhaust gas stream x .

[0086] The above object is also achieved by the above method for treating an exhaust gas stream generated by combustion in a combustion engine. The method includes:

[0087] - Capturing soot and ash generated by combustion by means of a particulate filter;

[0088] - Controlling the supply of an additive into the exhaust gas stream by means of a metering arrangement disposed downstream of a particulate filter, the additive being mixed with the exhaust gas stream by means of an evaporation arrangement disposed at the metering arrangement;

[0089] - Reducing nitrogen oxides NO in the exhaust gas stream by means of the supplied additive and a reduction catalyst arrangement disposed downstream of the metering arrangement; x ; and

[0090] - Interaction of the particles in the exhaust gas stream with at least one fibrous structure disposed downstream of the evaporation arrangement, the particles being produced by one or more of the supply of the additive into the exhaust gas stream and the transformation of the additive during its flow through the exhaust gas treatment system, wherein the at least one fibrous structure has a fibre volume ratio F / V in the range from 40% to 90%, such that:

[0091] -- The particles interact with the at least one fibrous structure and are thereby at least partially captured and removed by the at least one fibrous structure; and

[0092] -- Accumulation of soot and ash produced by combustion is at least partially avoided, which accumulation would affect the interaction of the at least one fibrous structure with the particles.

[0093] As stated above for the exhaust gas treatment system, the method has corresponding advantages.

[0094] The above object is also achieved by the above-described control system arranged for treating the exhaust gas stream produced by combustion in a combustion engine. The treatment includes:

[0095] - Capturing soot and ash produced by combustion by means of a particulate filter;

[0096] - Controlling the supply of an additive into the exhaust gas stream by means of a metering arrangement disposed downstream of the particulate filter, the additive being mixed with the exhaust gas stream by means of an evaporation arrangement disposed at the metering arrangement;

[0097] - Reducing nitrogen oxides NO in the exhaust gas stream by means of the supplied additive and a reduction catalyst arrangement disposed downstream of the metering arrangement; x ; and

[0098] - Interaction of the particles in the exhaust gas stream with at least one fibrous structure disposed downstream of the evaporation arrangement, the particles being produced by one or more of the supply of the additive into the exhaust gas stream and the transformation of the additive during its flow through the exhaust gas treatment system, wherein the at least one fibrous structure has a fibre volume ratio F / V in the range from 40% to 90%, such that:

[0099] -- causing the particles to interact with the at least one fibrous structure, whereby the particles are at least partially captured and removed by the at least one fibrous structure; and

[0100] -- at least partially avoiding the accumulation of soot and ash generated by combustion, which accumulation would affect the interaction between the at least one fibrous structure and the particles.

[0101] The control system has advantages corresponding to the above-mentioned advantages of the exhaust gas treatment system.

[0102] The above object is also achieved by the above computer program and computer program product.

[0103] The computer program and computer program product respectively have the corresponding advantages described above for the exhaust gas treatment system. Description of the Drawings

[0104] The present invention will be shown in more detail below with reference to the drawings, in which like reference numerals are used for like parts, and in which:

[0105] Figure 1 An example vehicle showing an exhaust gas treatment system that may include various embodiments of the present invention,

[0106] Figure 2a An example of an exhaust gas treatment system in which aspects and embodiments of the present invention may be implemented,

[0107] Figure 2b Showing various embodiments of the implementation of the present invention in an exhaust gas treatment system,

[0108] Figure 3a An example of an exhaust gas treatment system in which aspects and embodiments of the present invention may be implemented,

[0109] Figure 3b Showing various embodiments of the implementation of the present invention in an exhaust gas treatment system,

[0110] Figure 4 Showing a flowchart of a method for exhaust gas treatment according to the present invention, and

[0111] Figure 5 Showing a control device according to the present invention. Detailed Description of the Invention

[0112] Figure 1Schematically illustrated is an example vehicle 100 including exhaust gas treatment systems 250, 350, which may be exhaust gas treatment systems 250, 350 according to an aspect or embodiment of the present invention. The powertrain includes a combustion engine 101, which is conventionally connected to a transmission 103 via an output shaft 102 of the combustion engine 101 via a clutch 106. The output shaft 107 from the transmission 103 can drive wheels 113, 114, for example, via a final drive 108, such as a conventional differential, and drive shafts 104, 105 connected to the final drive 108.

[0113] The combustion engine 101, such as an internal combustion engine, can be controlled by the engine control system via a control device 115. Similarly, the clutch 106 and the transmission 103 can be controlled by the vehicle control system by means of one or more suitable control devices (not shown). Of course, the powertrain of the vehicle can also be of another type, such as a type with a conventional automatic transmission, or a type with a hybrid powertrain, etc.

[0114] The vehicle 100 also includes an exhaust gas treatment / purification system 250, 350 for treating / purifying exhaust emissions generated by combustion in the combustion chamber of the combustion engine 101.

[0115] Figure 2a Shown is the exhaust gas treatment system 250, which may show a so-called Euro VI system. The exhaust gas treatment system 250 is connected, for example, via an exhaust pipe 202 to a combustion engine 201, such as an internal combustion engine, where the exhaust gas generated during combustion, i.e., the exhaust gas stream 203, is indicated by an arrow. The exhaust gas stream 203 is directed to a coated diesel particulate filter (cDPF) 210, which is coated with a catalytic oxidation coating, for example, including at least one noble metal. Alternatively, instead of a coated diesel particulate filter (cDPF), a diesel oxidation catalyst (DOC) followed downstream by an uncoated diesel particulate filter (DPF) or a coated diesel particulate filter (cDPF) can be arranged in the exhaust gas treatment system 250. Thus, either the coated diesel particulate filter (cDPF) 210 or the diesel oxidation catalyst (DOC) followed by a diesel particulate filter (DPF / cDPF) is arranged downstream of the combustion engine 201 in the exhaust gas treatment system 250.

[0116] During combustion in the combustion engine 201, soot and ash are generated, and the coated diesel particulate filter (cDPF) 210, or the diesel particulate filter (DPF), is used to capture the soot and ash. The exhaust gas stream 203 is directed through the filter structure here, where the soot and ash from the exhaust gas stream 203 are captured during passage and stored in the particulate filter 210.

[0117] The catalytic coating in the coated diesel particulate filter (cDPF) 210 or the oxidation catalyst (DOC) has several functions and is generally mainly used to oxidize the remaining hydrocarbons C x H y (also referred to as HC) and carbon monoxide CO in the exhaust gas stream 203 into carbon dioxide CO2 and water H2O during exhaust gas treatment. Additionally, most of the nitrogen oxides NO present in the exhaust gas stream can be oxidized to nitrogen dioxide NO2. The oxidation of nitric oxide NO to nitrogen dioxide NO2 is important for NO2-based soot and ash oxidation in the filter and is also beneficial during potential subsequent reduction of nitrogen oxides NO x .

[0118] In this regard, the exhaust gas treatment system 250 further includes a reduction catalyst arrangement 220 disposed downstream of the coated diesel particulate filter (cDPF) 210. The reduction catalyst arrangement 220 may include at least one selective catalytic reduction (SCR) catalyst and / or at least one slip catalyst. The reduction catalyst arrangement 220 uses ammonia NH3 or a composition that can generate / form ammonia therefrom, such as urea, as an additive for reducing nitrogen oxides NO x in the exhaust gas stream 203. After passing through the components of the exhaust gas treatment system, the exhaust gas stream is discharged into the environment at the exhaust pipe.

[0119] However, the reaction rate of this reduction is affected by the ratio between nitric oxide NO and nitrogen dioxide NO2 in the exhaust gas stream, such that the reduction reaction in the forward direction is affected by the prior oxidation of NO to NO2 in the coated diesel particulate filter (cDPF) or the oxidation catalyst DOC.

[0120] The reduction catalyst arrangement 220 requires an additive to reduce the concentration of compounds such as nitrogen oxides NO x in the exhaust gas stream 203. Such an additive is injected into the exhaust gas stream downstream of the particulate filter 210 and upstream of the reduction catalyst arrangement 220, Figure 2a shown as the metering arrangement 270 in. Such additives are generally based on ammonia and / or urea or consist of substances from which ammonia can be extracted or released and may, for example, consist of AdBlue, which consists essentially of urea mixed with water. Urea forms ammonia upon heating (pyrolysis) and upon heterogeneous catalysis (hydrolysis) on an oxidation surface, which may, for example, consist of titanium dioxide TiO2 within the reduction catalyst arrangement 220. The exhaust gas treatment system may also include a separate hydrolysis catalyst.

[0121] An evaporation arrangement (not shown), which can consist of essentially any suitable hydrolysis coating and / or first mixture, such as a hydrolysis catalyst, is arranged at the metering arrangement 270. Then, the hydrolysis catalyst and / or first mixture is used to increase the rate of urea decomposition into ammonia, and / or to mix the additive with the emissions, and / or to evaporate the additive.

[0122] The additive can be provided from a container / tank 275, and the metering of the additive can be controlled by a control unit / system 290.

[0123] The exhaust gas treatment system 250 can also be equipped with a slip catalyst (SC) 240, which is arranged downstream of the reduction catalyst arrangement 220 to oxidize any excess ammonia that may remain after the reduction catalyst arrangement 220, and / or to assist the reduction catalyst arrangement 220 in further reducing NO x . Thus, the slip catalyst SC 240 can provide the potential to improve the system's total conversion / reduction of NO x .

[0124] The exhaust gas treatment system 250 can also be equipped with one or more sensors, such as one or more NO x and / or temperature sensors, for determining the nitrogen oxides and / or temperature in the exhaust gas treatment system.

[0125] Figure 3a Another exhaust gas treatment system 350 is schematically shown, which is connected to a combustion engine 301, such as an internal combustion engine, via an exhaust pipe 302. The exhaust gas is generated by combustion in the engine 301, and the exhaust gas stream 303 (indicated by the arrow) is directed to an upstream dosing device 371 arranged to add an additive to the exhaust gas stream 303. The upstream reduction catalyst device 330 is arranged downstream of the upstream dosing device 371. The upstream reduction catalyst device 330 is arranged to reduce the nitrogen oxides NO in the exhaust gas stream 303 by using the additive added to the exhaust gas stream by the upstream dosing device 371 x . More specifically, the upstream reduction catalyst device 330 uses an additive such as ammonia NH3 or a substance that can generate / form / release ammonia to reduce the nitrogen oxides NO in the exhaust gas stream 303 x . This additive can consist of, for example, AdBlue as described above and can be provided from a container / tank 375. The injection of the additive can be controlled by a control unit / system 390.

[0126] According to various embodiments, the upstream reduction catalyst device 330 can include an upstream selective catalytic reduction (SCR) catalyst and / or an upstream slip catalyst. The upstream slip catalyst can be a conventional ammonia slip catalyst (ASC) or can be a multifunctional slip catalyst (SC), which is mainly used to reduce the nitrogen oxides NO x, and secondly for oxidizing the additives in the exhaust gas stream 303.

[0127] The multi-functional slip catalyst (SC) includes nitrogen oxides NO in direct contact with the exhaust gas stream 303 x reduction coating. The multi-functional slip catalyst (SC) also includes one or several substances included in the platinum group metals, and / or one or several other substances providing properties similar to those of the platinum group metals.

[0128] Thus, according to various embodiments, the upstream reduction catalyst device 330 may include, for example, one of the following:

[0129] - An upstream selective catalytic reduction catalyst SCR1, followed downstream by an integrated or separate upstream slip catalyst SC1, where the upstream slip catalyst SC1 is mainly arranged for reducing nitrogen oxides NO x , and secondly arranged for oxidizing the additive residues in the exhaust gas stream 303;

[0130] - An upstream slip catalyst SC1, followed downstream by an integrated or separate upstream selective catalytic reduction catalyst SCR1, where the upstream slip catalyst SC1 is mainly arranged for reducing nitrogen oxides NO x , and secondly arranged for oxidizing the additives in the exhaust gas stream 303;

[0131] - An upstream slip catalyst SC1, followed downstream by an integrated or separate upstream selective catalytic reduction catalyst SCR1, followed downstream by an integrated or separate additional upstream slip catalyst SC 1b , where the upstream slip catalyst SC1 and / or the additional upstream slip catalyst SC 1b is mainly arranged for reducing nitrogen oxides NO x , and secondly arranged for oxidizing the additives in the exhaust gas stream 303;

[0132] - An upstream slip catalyst SC1, which is mainly arranged for reducing nitrogen oxides NO x , and secondly arranged for oxidizing the additive residues in the exhaust gas stream 303.

[0133] Downstream of the upstream reduction catalyst device 330, the exhaust gas treatment system 350 further includes a coated diesel particulate filter (cDPF) 310, which is coated with a catalytic oxidation coating, for example including at least one noble metal for trapping and oxidizing soot and ash. Alternatively, instead of the coated diesel particulate filter (cDPF), a diesel oxidation catalyst (DOC) followed downstream by a diesel particulate filter (DPF / CDPF) can be arranged in the exhaust gas treatment system 350. Thus, the coated diesel particulate filter (cDPF) 310, or the diesel oxidation catalyst (DOC) followed by the diesel particulate filter (DPF / cDPF), is arranged downstream of the upstream reduction catalyst device 330 in the exhaust gas treatment system 350.

[0134] Downstream of the particulate filter 310, the exhaust gas treatment system 350 includes a downstream dosing device 372 arranged to supply an additive to the exhaust gas stream 303, where such a second additive includes ammonia NH3, or a substance that can produce / form / release ammonia, such as AdBlue, as described above. The downstream additive can here be the same additive as the above-mentioned additive injected by the upstream dosing device 371 and may also be from the same container / tank 375. Alternatively, the additives injected by the upstream dosing device 371 and the downstream dosing device 372 can also be of different types and can be from different tanks. The injection carried out by the downstream dosing device 372 can be controlled by the control unit / system 390.

[0135] According to various embodiments of the present invention, an evaporation arrangement can be arranged respectively at the upstream metering arrangement 371 and / or the downstream metering arrangement 372 to increase the rate of urea decomposition into ammonia, and / or to mix the additive with the emissions, and / or to evaporate the additive.

[0136] The exhaust gas treatment system 350 further includes a downstream reduction catalyst device 320 arranged downstream of the downstream dosing device 372. The downstream reduction catalyst device 320 is arranged to reduce nitrogen oxides NO in the exhaust gas stream 303 by using the additive injected by the downstream dosing device 372 and possibly also the remaining additive injected by the upstream dosing device 371 in the exhaust gas stream 303 x 。

[0137] The downstream reduction catalyst device 320 can include at least one selective catalytic reduction catalyst and / or at least one slip catalyst.

[0138] Thus, according to various embodiments, the downstream reduction catalyst device 320 can include one of the following:

[0139] - A downstream selective catalytic reduction catalyst SCR2; and

[0140] a downstream selective catalytic reduction catalyst SCR2, followed downstream by an integrated or separate downstream slip catalyst SC2, wherein the downstream slip catalyst SC2 is arranged to oxidize the additive residue and / or assist the SCR2 in additionally reducing the nitrogen oxides NO in the exhaust gas flow 303 x .

[0141] After passing through the components of the exhaust gas treatment system, the exhaust gas flow is discharged into the environment at an exhaust pipe of the exhaust gas treatment system.

[0142] The exhaust gas treatment system 350 may also be equipped with one or more sensors (not shown), such as one or more NO x sensor and / or one or several temperature sensors, which are arranged to respectively determine the NO x concentration and temperature.

[0143] By using Figure 3a In the exhaust gas treatment system 350 shown in FIG. 1 , the upstream reduction catalyst device 330 and the downstream reduction catalyst device 320 can each be used to reduce nitrogen oxides NO x The catalyst characteristics are selected and / or optimized relative to the volumes of the upstream reduction catalyst device 330 and the downstream 320 reduction catalyst device.

[0144] The particulate filter 310 can be used to improve efficiency by considering how its thermal mass, i.e., its thermal inertia, affects the temperature of the downstream reduction catalyst 320. By considering the thermal inertia of the particulate filter 310, the upstream reduction catalyst device 330 and the downstream reduction catalyst device 320 can be optimized with respect to the specific temperature function that each will experience.

[0145] The exhaust treatment system 350 reduces nitrogen oxides (NO) in the exhaust gas flow in substantially all driving modes. x The drive modes include in particular cold starts and throttling, ie an increased requested torque.

[0146] According to various embodiments, the slip catalyst SC may be a catalyst arranged to oxidize additives in the exhaust gas flow 303 and / or arranged so that it can reduce residual nitrogen oxides NO in the exhaust gas flow 303. x catalyst.

[0147] In more detail, according to various embodiments, such a slip catalyst SC may, for example, be arranged primarily to reduce nitrogen oxides NO x , followed by the oxidation additive. In other words, the slip catalyst SC processes the additive and the nitrogen oxides NO xThe escape residues of both. This can also be described as the escape catalyst SC being an extended ammonia slip catalyst ASC that is arranged to reduce nitrogen oxides NO in the exhaust gas stream 303 x , such that a universal / multi-functional escape catalyst SC that can handle several types of escapes is obtained, which means that it can handle both additives and nitrogen oxides NO x The residues of both. At least the following reactions can take place, for example, in the multi-functional escape catalyst SC, which reduces nitrogen oxides NO x and oxidizes additives:

[0148] NH3 + O2 → N2; (Equation 1)

[0149] and

[0150] NO x + NH3 → N2 + H20. (Equation 2)

[0151] Here, the reaction according to Equation 1 causes the oxidation of the residues of additives including ammonia. The reaction according to Equation 2 causes the reduction of nitrogen oxides NO x .

[0152] Thus, additives can be oxidized here, and the residues of ammonia NH3, isocyanic acid HNCO, urea, or the like can be oxidized. These residues of additives, namely ammonia NH3, HNCO, urea, or the like, can also be used here to oxidize nitrogen oxides NO x .

[0153] To obtain these properties, that is, to obtain a multi-functional escape catalyst, according to one embodiment, the escape catalyst can include one or several substances included in platinum group metals (PGM; platinum group metals), that is, one or several of iridium, palladium, palladium, platinum, rhodium, and ruthenium. The escape catalyst can also include one or several other substances that impart properties similar to those of platinum group metals to the escape catalyst. The escape catalyst can also include a NO x reduction coating, where the coating can include, for example, Cu zeolite or Fe zeolite or vanadium. The zeolite can be activated here with active metals such as copper (Cu) or iron (Fe).

[0154] For both the upstream reduction catalyst device 330 and the downstream reduction catalyst device 320, their catalytic characteristics can be selected based on the environment to which they are or will be exposed. Additionally, the catalytic characteristics of the upstream reduction catalyst device 330 and the downstream reduction catalyst device 320 can be adapted such that the catalytic characteristics can allow them to function symbiotically with each other. The upstream reduction catalyst device 330 and the downstream reduction catalyst device 320 can also include one or several materials that provide the catalytic characteristics. For example, transition metals, such as vanadium and / or tungsten, can be used in catalysts such as V2O5 / WO3 / TiO2. Metals such as iron and / or copper can also be included in the upstream reduction catalyst device 330 and / or the downstream reduction catalyst device 320, for example, in zeolite-based catalysts.

[0155] According to the present invention, at least one fiber structure 280a-d, 380a-d is arranged downstream of the evaporation device to interact with certain small-sized additive-based particles in the exhaust gas streams 203, 303. As mentioned above, here, the evaporation device is arranged at the metering supply arrangements 270, 372. As mentioned above, these particles may be generated by supplying additives to the exhaust gas streams 203, 303 and / or by the transformation of additives when the additives flow through the exhaust gas treatment systems 250, 350. The particles can include urea and / or urea-based polymerization by-products. The injected additives include ammonia and / or substances from which ammonia can be extracted and / or released.

[0156] Therefore, respectively, Figure 2b the exhaust gas treatment system 250 shown in Figure 3b includes an evaporation device arranged at the metering supply arrangement 270, and Figure 2b and 3b the exhaust gas treatment system 350 shown in includes an evaporation device arranged at the downstream metering supply device 372. At least one fiber structure 280a-d, 380a-d is arranged downstream of the evaporation device, as shown in

[0157] At least one fiber structure 280a-d, 380a-d has a fiber volume ratio F / V, and the F / V is selected such that additive-based particles interact with at least one fiber structure 280a-d, 380a-d, whereby the particles are at least partially captured and removed from the exhaust gas streams 203, 303. The fiber volume ratio F / V is also selected in the range of 40% to 90% such that the accumulation of soot and ash generated by combustion is at least partially avoided. Therefore, the interaction between the at least one fiber structure 280a-d, 380a-d and the particles is not affected.

[0158] The fiber volume ratio F / V is the ratio between the solid fiber volume F and the total available volume V, which should be understood as the volume fraction of the solid material contained in the fiber structure relative to the total volume of the fiber structure. This can also be interpreted as the fiber volume fraction F / V.

[0159] According to an embodiment, at least one fiber structure 280a-d, 380a-d is arranged at least 0.1 m downstream of the metering supply arrangement, i.e., respectively downstream of the evaporation arrangement at the metering supply arrangement 270 shown or Figure 2b downstream of the downstream evaporation arrangement at the downstream metering supply device 372 shown. For example, at least one fiber structure 280a-d, 380a-d can be arranged at least 0.5 m downstream of the metering supply arrangement or at any other suitable distance downstream of the metering supply arrangement such that it does not interfere with the injection of the additive. Figure 3b For example, at least one fiber structure 280a-d, 380a-d can be arranged at least 0.5 m downstream of the metering supply arrangement or at any other suitable distance downstream of the metering supply arrangement such that it does not interfere with the injection of the additive.

[0160] According to various embodiments, in the case where at least one fiber structure 280d, 380d is arranged downstream of the reduction catalyst arrangement 220, the downstream reduction catalyst device 320 and / or the escape catalyst 240, 340, at least one fiber structure 280d, 380d can be arranged respectively Figure 2b at least 1.5 m downstream of the metering supply arrangement 270 shown in Figure 3b or at least 1.5 m downstream of the downstream metering supply device 372 shown in Figure 2b For an exhaust gas treatment system having, for example, a vertical exhaust pipe, at least one fiber structure 280d, 380d can be arranged respectively Figure 3b at least 3 m downstream of the metering supply arrangement 270 shown in

[0161] According to an embodiment, at least one fiber structure 280a is included in the reduction catalyst arrangement 220, as shown in Figure 2b

[0162] According to an embodiment, at least one fiber structure 380a is included in the downstream reduction catalyst device 320, as shown in Figure 3b

[0163] According to an embodiment, at least one fiber structure 280b-d is arranged at 225, 240, 245 downstream of the reduction catalyst arrangement 220, as shown in Figure 2b

[0164] According to an embodiment, at least one fiber structure 380b-d is arranged at 325, 340, 345 downstream of the downstream reduction catalyst device 320, as shown in Figure 3b

[0165] ​​​​According to an embodiment, at least one fibrous structure 280b is arranged at 225 downstream of the reduction catalyst arrangement 220 and upstream of the slip catalyst arrangement 240, as Figure 2b shown in

[0166] According to an embodiment, at least one fibrous structure 380b is arranged at 325 downstream of the downstream reduction catalyst device 320 and upstream of the slip catalyst arrangement 340, as Figure 3b shown in

[0167] According to an embodiment, at least one fibrous structure 280c is included in the slip catalyst arrangement 240, as Figure 2b shown in

[0168] According to an embodiment, at least one fibrous structure 380c is included in the slip catalyst arrangement 340, as Figure 3b shown in

[0169] According to an embodiment, at least one fibrous structure 280d is arranged at 245 downstream of the slip catalyst arrangement 240, as Figure 2b shown in

[0170] According to an embodiment, at least one fibrous structure 380d is arranged at 345 downstream of the slip catalyst arrangement 340, as Figure 3b shown in

[0171] According to an embodiment, the reduction catalyst arrangements 220, 320 include at least one selective catalytic reduction catalyst and / or at least one slip catalyst.

[0172] According to an embodiment, at least one of the fibrous structures 280a-d, 380a-d includes at least one section arranged to be heated by the exhaust gas flow 203, 303 to an interaction temperature T I when the exhaust gas flow passes through at least one of the fibrous structures 280a-d, 380a-d. The interaction temperature T I exceeds the particle temperature T at which particle thermal dissolution occurs P ; T I >T P . Additionally, at least one of the fibrous structures 280a-d, 380a-d is arranged in terms of its fiber volume ratio F / V to interact with the exhaust gas flow 203, 303 and thus also with the particles such that at least a portion of the particles physically contacts the heated at least one section. Thereby, the particles impinging on the at least one heated section are thermally dissolved and removed from the exhaust gas flow. According to an embodiment, the interaction temperature T I can be at least 150 °C.

[0173] During cold start, i.e., when at least one section has been heated to the interaction temperature T IPrior thereto, some particles may initially accumulate in at least one of the fiber structures 280a-d, 380a-d. However, when at least one section has been heated to the interaction temperature T I the accumulated particles are thermally dissolved and removed from the exhaust gas streams 203, 303.

[0174] According to an embodiment, at least one of the fiber structures 280a-d, 380a-d at least partially comprises an inert material, i.e., a chemically inactive material that is not prone to participate in chemical reactions. At least one of the fiber structures 280a-d, 380a-d may be made of an inert material, or an inert material may be coated on at least one of the fiber structures 280a-d, 380a-d. The inert material may be a metallic and / or non-metallic material, such as cordierite, silicon carbide, aluminum titanate, and / or polymer composite.

[0175] According to an embodiment, at least the at least one of the fiber structures 280a-d, 380a-d at least partially comprises an active catalytic material. At least one of the fiber structures 280a-d, 380a-d may be made of an active catalytic material, or an active catalytic material may be coated on at least one of the fiber structures 280a-d, 380a-d. The active catalytic material may be, for example, a noble metal, vanadium, iron (Fe), copper, titanium, tungsten, and / or aluminum.

[0176] According to an embodiment, at least one of the fiber structures 280a-d, 380a-d includes a porous structure / configuration / construction / texture that is arranged such that the exhaust gas streams 203, 303 flow therethrough. The porous texture has the above-mentioned fiber volume ratio F / V, which enables the particles to interact with at least one of the fiber structures 280a-d, 380a-d, i.e., with the porous texture, whereby the particles are dissolved and removed from the exhaust gas streams 203, 303.

[0177] According to an embodiment, at least one of the fiber structures 280a-d, 380a-d has a cross-sectional area A in inches 2 and a length L in inches such that the area-to-length ratio A / L of at least one of the fiber structures 280a-d, 380a-d has a value of at least 17 inches and at most 150 inches in inches; 17 ≤ A / L ≤ 150 inches. This range of the area-to-length ratio A / L can be used, for example, to effectively provide sufficient interaction between the at least one fiber structure and the additive-based particles. It should be noted that due to its simple construction, the at least one fiber structure may have a very short length L relative to its cross-sectional area A.

[0178] If the area A is measured in mm 2 and the length L is measured in mm, then the above range corresponds to an area-to-length ratio A / L range of 425 ≤ A / L ≤ 3810 mm.

[0179] Of importance is the ratio between the area A of the cross-section and the length L of at least one fibrous structure. The at least one fibrous structure can, for example, have a shorter length L with respect to the area A than the filter structure of a conventional particulate filter.

[0180] The at least one fibrous structure 280a-d, 380a-d can have many different shapes. According to various embodiments, the at least one fibrous structure 280a-d, 380a-d has a circular cross-section, has an elliptical cross-section, has a rectangular cross-section or has another suitable form. The cross-section of the at least one fibrous structure can have substantially any shape that is suitable for connecting the at least one fibrous structure to upstream and / or downstream components in the exhaust gas treatment systems 250, 350.

[0181] According to an embodiment, the fiber volume ratio F / V of the at least one fibrous structure 280a-d, 380a-d is in the range of 40% to 70%.

[0182] Thereby, an interaction between the particles and the at least one fibrous structure 280a-d, 380a-d is provided such that additive-based particles are removed from the exhaust gas streams 203, 303.

[0183] According to one aspect of the invention, there is provided a method 400 for treating exhaust gas streams 203, 303 generated by combustion in combustion engines 201, 301.

[0184] In a first step 410, soot and ash generated by combustion are captured by means of particulate filters 210, 310.

[0185] In a second step 420, the supply of additive to the exhaust gas stream is controlled by means of a metering arrangement 270, 372 arranged downstream of the particulate filters 210, 310. The additive is mixed with the exhaust gas stream by means of an evaporation arrangement arranged at the metering arrangement 270, 372.

[0186] In a third step 430, nitrogen oxides NO in the exhaust gas streams 203, 303 x are reduced by means of the supplied additive and a reduction catalyst arrangement 220, 320 arranged downstream of the metering arrangement 270, 372.

[0187] In a fourth step 440, the particles in the waste gas streams 203, 303 are made to interact with at least one fibrous structure 280a-d, 380a-d disposed downstream of the evaporation arrangement. As described above, these particles are produced by one or more of the supply of the additive to the waste gas streams 203, 303 and the transformation of the additive during its flow through the waste gas treatment systems 250, 350. The at least one fibrous structure 280a-d, 380a-d has a fiber volume ratio F / V in the range of 40% to 90%, such that:

[0188] -- the particles are made to interact with the at least one fibrous structure 280a-d, 380a-d, whereby the at least one fibrous structure 280a-d, 380a-d captures and removes them at least in part; and

[0189] -- at least in part, the accumulation of soot and ash produced by the combustion, which would affect the interaction of the at least one fibrous structure 280a-d, 380a-d with the particles, is avoided.

[0190] Those skilled in the art will recognize that the method for treating waste gas streams according to the present invention can also be implemented in a computer program, which, when executed on a computer, will cause the computer to perform the method. The computer program typically forms part of a computer program product 503, where the computer program product includes a suitable digital non-volatile / permanent / persistent / durable storage medium on which the computer program is stored. The non-volatile / permanent / persistent / durable computer-readable medium consists of a suitable memory, such as: ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable PROM), flash memory, EEPROM (electrically erasable PROM), hard disk device, etc.

[0191] Figure 5 A control device 500 is schematically shown. The control device 500 includes a computing unit 501, which can essentially consist of a processor or microcomputer of a suitable type, such as a circuit for digital signal processing (digital signal processor, DSP) or a circuit with a predetermined specific function (application-specific integrated circuit, ASIC). The computing unit 501 is connected to a memory unit 502 installed in the control device 500, thereby providing, for example, the stored program code and / or the stored data to the computing device 501, which the computing device 501 needs for calculations. The computing unit 501 is also arranged to store the intermediate or final results of the calculations in the memory unit 502.

[0192] In addition, the control device 500 is equipped with devices 511, 512, 513, 514 for receiving and transmitting input and output signals respectively. These input and output signals can include waveforms, pulses or other attributes, which can be detected as information by the devices 511, 513 for receiving input signals and can be converted into signals that can be processed by the computing unit 501. These signals are then provided to the computing unit 501. The devices 512, 514 for transmitting output signals are arranged to convert the calculation results from the computing unit 501 into output signals for transmission to other parts of the vehicle's control system and / or the components targeted by the signals.

[0193] Each of the connections to the devices for receiving and transmitting input and output signals can consist of one or several of the following: cables, data buses such as CAN (Controller Area Network) buses, MOST (Media Oriented Systems Transport) buses, or any other bus configuration; or consist of wireless connections.

[0194] Those skilled in the art will recognize that the above-mentioned computer can consist of the computing unit 501, and the above-mentioned memory can consist of the memory unit 502.

[0195] Generally, the control system in modern vehicles consists of a communication bus system, which consists of one or several communication buses to connect multiple electronic control units (ECUs) or controllers and different components located on the vehicle. Such a control system can include a large number of control devices, and the responsibility for specific functions can be distributed among more than one control device. Therefore, the vehicles of the type shown usually include significantly more control devices than Figure 5 the control device shown in, which is well known to those skilled in the art.

[0196] As those skilled in the art will recognize, Figure 5 the control device 500 in can respectively include Figure 2a one or several of the control devices 290 and 390 in -b and 3a-b.

[0197] In the shown embodiment, the present invention is implemented in the control device 500. However, the present invention can also be implemented in whole or in part in one or several other control devices already existing in the vehicle, or in a control device dedicated to the present invention.

[0198] Those skilled in the art will also recognize that the above-mentioned exhaust gas treatment system can be modified according to different embodiments of the method according to the present invention. In addition, the present invention relates to a motor vehicle 100, such as a car, a truck or a bus, or another unit including at least one exhaust gas treatment system according to the present invention, such as a ship or a voltage / current generator.

[0199] The present invention is not limited to the embodiments of the present invention described above, but relates to and includes all embodiments within the scope of the appended independent claims.

Claims

1. An exhaust gas treatment system (250, 350) arranged for treating an exhaust gas flow (203, 303) generated by combustion in a combustion engine (201, 301), the exhaust gas treatment system comprising: - A particulate filter (210, 310) arranged to capture soot and ash produced by the combustion; - A metering arrangement (270, 372) arranged downstream of the particulate filter (210, 310) for supplying an additive into the exhaust gas flow (203, 303), the additive being mixed with the exhaust gas flow (203, 303) by an evaporation arrangement arranged at the metering arrangement (270, 372); - Reduction catalyst arrangement (220, 320), which is arranged downstream of the metering arrangement (270, 372), for reducing nitrogen oxides NO in the waste gas stream (203, 303) by using the supplied additive x ; And - At least one fibrous structure (280a - d, 380a - d) arranged downstream of the evaporation arrangement for interacting with particles in the exhaust gas flow (203, 303), the particles being produced by one or more of the supply of the additive into the exhaust gas flow (203, 303) and the transformation of the additive as it flows through the exhaust gas treatment system (250, 350), wherein the at least one fibrous structure (280a - d, 380a - d) has a fiber volume ratio F / V in the range of 40% to 90%, such that: -- The particles are made to interact with the at least one fibrous structure (280a - d, 380a - d), thereby being at least partially captured and removed by the at least one fibrous structure (280a - d, 380a - d); And -- The accumulation of soot and ash produced by the combustion is at least partially avoided, the accumulation of which would affect the interaction of the at least one fibrous structure (280a - d, 380a - d) with the particles.

2. The exhaust gas treatment system (250, 350) according to claim 1, wherein the at least one fibrous structure (280a - d, 380a - d) is arranged at least 0.1 m downstream of the metering arrangement (270, 372).

3. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 2, wherein the at least one fibrous structure (280a, 380a) is included in the reduction catalyst arrangement (220, 320).

4. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 2, wherein the at least one fibrous structure (280b - d, 380b - d) is arranged downstream of the reduction catalyst arrangement (220, 320).

5. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 2, which further comprises a slip catalyst arrangement (240, 340) arranged downstream of the reduction catalyst arrangement (220, 320) for oxidizing additive residues in the exhaust gas flow (203, 303), wherein the at least one fibrous structure (280b, 380b) is arranged downstream of the reduction catalyst arrangement (220, 320) and upstream of the slip catalyst arrangement (240, 340).

6. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 2, further comprising an escape catalyst arrangement (340, 3,40) disposed downstream of the reduction catalyst arrangement (220, 320) for oxidizing additive residues in the exhaust gas stream (203, 303), wherein the at least one fibrous structure (280c, 380c) is included in the escape catalyst arrangement (240, 340).

7. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 2, further comprising an escape catalyst arrangement (240, 340) disposed downstream of the reduction catalyst arrangement (220, 320) for oxidizing additive residues in the exhaust gas stream (203, 303), wherein the at least fibrous structure (280d, 380d) is disposed downstream of the escape catalyst arrangement (240, 340).

8. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 7, wherein the reduction catalyst arrangement (220, 320) comprises one or more of the following groups: - at least one selective catalytic reduction catalyst; - at least one escape catalyst.

9. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 8, wherein: - The at least one fibrous structure (280a-d, 380a-d) includes at least one section arranged to be heated by the waste gas flow (203, 303) flowing therethrough to an interaction temperature T I , the interaction temperature T I exceeding the particulate temperature T at which the particles thermally dissolve P ; T I > T P ; and - the at least one fibrous structure (280a-d, 380a-d) is arranged to interact with the particles such that the particles are at least partially in physical contact with the at least one heated section.

10. The exhaust gas treatment system (250, 350) according to claim 9, wherein the interaction temperature T I is at least 150 °C.

11. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 10, wherein the at least one fibrous structure (280a-d, 380a-d) at least partially comprises an inert material.

12. The exhaust gas treatment system (250, 350) according to claim 11, wherein the inert material is one or more of the following groups: - metallic materials; and - non-metallic materials.

13. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 12, wherein the at least one fibrous structure (280a-d, 380a-d) at least partially comprises an active catalytic material.

14. The exhaust gas treatment system (250, 350) according to any one of claims 11 to 13, wherein the material is coated on the at least one fibrous structure (280a-d, 380a-d).

15. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 14, wherein the at least one fibrous structure (280a-d, 380a-d) comprises a porous configuration arranged to allow the exhaust gas stream (203, 303) to flow therethrough.

16. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 15, wherein: - The at least one fibrous structure (280a-d, 380a-d) has a cross-sectional area A in inches 2 and a length L in inches; and - the area-to-length ratio A / L of the at least one fibrous structure (280a-d, 380a-d) has a value of at least 17 inches and at most 150 inches; 17 ≤ A / L ≤ 150 inches.

17. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 16, wherein the additive comprises one or more of the following groups: - ammonia, and - a substance capable of extracting and / or releasing ammonia therefrom.

18. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 1178, wherein the particles comprise one or more of the following groups: - urea; and - urea-based polymer by-products.

19. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 18, wherein the fiber volume ratio F / V of the at least one fiber structure (280a-d, 380a-d) is in the range of 40% to 70%.

20. The exhaust gas treatment system (250, 350) according to any one of claims 1 to 19, comprising: - an upstream metering device (371) arranged to supply an additive into the exhaust gas stream (303); - An upstream reduction catalyst device (330) is arranged downstream of the upstream metering supply device (371) for reducing nitrogen oxides NO in the exhaust gas stream (303) by utilizing the supplied additive x ; - the particulate filter (310) arranged downstream of the upstream reduction catalyst device (330) to capture soot and ash generated by the combustion; - the metering arrangement arranged as a downstream metering device (372) downstream of the particulate filter (310) to supply an additive into the exhaust gas stream (303), the additive being mixed with the exhaust gas stream (203, 303) by an evaporation arrangement arranged at the downstream metering device (372) as a downstream evaporation arrangement; - The reduction catalyst arrangement is arranged as a downstream reduction catalyst device (320) downstream of the downstream metering device (372) to reduce nitrogen oxides NO in the exhaust gas stream (303) by utilizing the supplied additive x ; and - the at least one fiber structure (280a-d, 380a-d) arranged downstream of the downstream evaporation arrangement.

21. The exhaust gas treatment system (250, 350) according to claim 20, wherein the upstream reduction catalyst device (330) comprises one or more of the following groups: - an upstream selective catalytic reduction catalyst; and - an upstream slip catalyst.

22. A method (400) for treating an exhaust gas stream (250, 350) generated by combustion in a combustion engine (201, 301), the method comprising: - capturing (410) soot and ash generated by the combustion by means of a particulate filter (210, 310); - controlling (420) the supply of an additive into the exhaust gas stream (203, 303) by means of a metering arrangement (270, 372) arranged downstream of the particulate filter (210, 310), the additive being mixed with the exhaust gas stream by an evaporation arrangement arranged at the metering arrangement (270, 372); - reducing (430) nitrogen oxides NO in the exhaust gas stream (203, 303) by utilizing a supplied additive and a reduction catalyst arrangement (220, 320) disposed downstream of the metering arrangement (270, 372) x ; and - causing particles in the exhaust gas stream (203, 303) to interact (440) with at least one fibrous structure (280a-d, 380a-d) disposed downstream of the evaporation arrangement, the particles being generated by one or more of the supply of the additive to the exhaust gas stream (203, 303) and the transformation of the additive as it flows through the exhaust gas treatment system (250, 350), wherein the at least one fibrous structure (280a-d, 380a-d) has a fiber volume ratio F / V in the range of 40% to 90%, such that: -- causing the particles to interact with the at least one fibrous structure (280a-d, 380a-d), whereby the particles are at least partially captured and removed by the at least one fibrous structure (280a-d, 380a-d); and -- at least partially avoiding the accumulation of soot and ash particles generated by the combustion, the accumulation of which would affect the interaction of the at least one fibrous structure (280a-d, 380a-d) with the particles.

23. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to perform the method according to claim 22.

24. A computer-readable medium comprising instructions which, when executed by a computer, cause the computer to perform the method according to claim 22.

25. A control system (500) arranged to control an exhaust gas treatment system (250, 350) for treating an exhaust gas stream (203, 303) generated by combustion in a combustion engine (201, 301), the treatment comprising: - capturing (410) soot and ash generated by the combustion by means of a particulate filter (210, 310); - controlling (420) the supply of an additive to the exhaust gas stream (203, 303) by means of a metering arrangement (270, 372) disposed downstream of the particulate filter (210, 310), the additive being mixed with the exhaust gas stream (203, 303) by an evaporation arrangement disposed at the metering arrangement (270, 372); -Reducing (430) nitrogen oxides NO in the exhaust gas stream (203, 303) by utilizing a supplied additive and a reduction catalyst arrangement (220, 320) disposed downstream of the metering arrangement (270, 372) x ; and - causing particles in the exhaust gas stream (203, 303) to interact (440) with at least one fibrous structure (280a-d, 380a-d) disposed downstream of the evaporation arrangement, the particles being generated by one or more of the supply of the additive to the exhaust gas stream (203, 303) and the transformation of the additive as it flows through the exhaust gas treatment system (250, 350), wherein the at least one fibrous structure (280a-d, 380a-d) has a fiber volume ratio F / V in the range of 40% to 90%, such that: -- causing the particles to interact with the at least one fibrous structure (280a-d, 380a-d), whereby the particles are at least partially captured and removed by the at least one fibrous structure (280a-d, 380a-d); and --At least partially avoids the accumulation of soot and ash particles generated by the combustion, and the accumulation will affect the interaction between the at least one fibrous structure (280a-d, 380a-d) and the particles.

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