KR20190090555A - Integrated after exhaust treatment apparatus using metal fiber support - Google Patents

Abstract

The present invention relates to an integrated post-exhaust treatment apparatus using a metal fiber support, comprising: an exhaust pipe connected to an internal combustion engine to exhaust a first exhaust gas generated by the internal combustion engine; a selective catalytic reduction filter (SRF) connected to the exhaust pipe to receive the first exhaust gas from the exhaust pipe, reduce and remove nitrogen oxide in the first exhaust gas under a thin air-fuel ratio operation condition, and collect and remove particle materials in the first exhaust gas; and a lean NOx trap filter (LTF) connected to the SRF to receive a second exhaust gas primarily purified in the SRF, occlude the nitrogen oxide in the second exhaust gas under the thin air-fuel ratio operation condition, remove the nitrogen oxide under a temporary rich air-fuel ratio operation condition, oxidize and remove hydrocarbon, carbon monoxide, ammonia, etc., under the thin air-fuel ratio operation condition, and collect and remove particle materials in the second exhaust gas. The present invention aims to provide the integrated post-exhaust treatment apparatus using the metal fiber support, which is able to integrally compose various types of post-exhaust treatment apparatuses for removing hazardous substances in exhaust gas generated by an internal combustion engine.

Description

Integrated exhaust aftertreatment device using metal fiber carrier {INTEGRATED AFTER EXHAUST TREATMENT APPARATUS USING METAL FIBER SUPPORT}

The present invention relates to an integrated exhaust aftertreatment apparatus using a metal fiber carrier, and more particularly, it can be effectively implemented by integrating various types of exhaust aftertreatment apparatuses for removing harmful substances in exhaust gas generated from an internal combustion engine. The present invention relates to an integrated exhaust aftertreatment apparatus using a metal fiber carrier which can improve the problems caused by the use of a ceramic carrier.

In general, engines of internal combustion engines that use hydrocarbon-based fuels such as gasoline or diesel fuel have carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), particulate matter (PM, Particulate Matter) by incomplete combustion and chemical reactions. Exhaust gas containing harmful substances such as

Therefore, various types of exhaust post-treatment devices are installed in the exhaust path of the engine of the internal combustion engine to prevent exhaust gas containing harmful substances from being exhausted into the air.

The exhaust post-treatment apparatus as described above is used in various types depending on the type of gas to be purified and the purification method. For example, recent exhaust after-treatment devices include Gasoline Particulate Filter (GPF), Lean NOx Trap (NOx occlusion catalyst), Selective Catalytic Reduction (SCR), and Catalyst Diesel Particulate Filter (CDPF). Catalytic filter) and SDPF (SCR + Diesel Particulate Filter) are widely used.

Here, in the past, harmful gases emitted from gasoline engines could be solved with TWC (Three-way catalyst) alone, but in recent years, as the exhaust regulations are strengthened, more precious metal catalysts have to be used, and gasoline particulate matter emissions have been reduced. Additional GPFs are used.

In addition, in diesel engines, the use of simple DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particulate Filter) have been solved.However, due to recent exhaust regulations, LNT and SCR and CDPF are used in combination to effectively burn the collected particulate matter.

In addition, carbon dioxide (CO2) generated during combustion in an engine of an internal combustion engine is not a toxic gas directly harmful to the human body, but is regulated as a global warming gas (GHG) and is regulated in total amount, and the regulation is gradually being strengthened. In the case of automobiles, there is a method of reducing fuel consumption by improving the thermal efficiency of the engine to reduce the generation of carbon dioxide per unit mileage (g / km) or by reducing the total weight of the vehicle. In the short term, the weight of automobile parts can be reduced and the weight can be realized.

Recently, various types of exhaust post-treatment devices have been used in combination to further reduce the amount of harmful substances contained in the exhaust gas. For example, Japanese Patent Application Laid-Open No. 2014-005735 (Invention: Exhaust Gas Purification System, Publication Date: January 16, 2014) discloses an exhaust gas purification system for reducing costs while reducing the purification performance of exhaust gas. Is disclosed. In other words, Japanese Laid-Open Patent Publication No. 2014-005735 discloses a structure in which a first DOC, a CSF (catalized soot filter), a second DOC, and an SCR are connected in series to an exhaust pipe of a diesel engine toward a downstream side. .

When using various types of exhaust aftertreatment in combination as described above, it is possible to significantly reduce the harmful substances discharged to the exhaust gas to satisfy the regulatory value, thereby greatly increasing the prevention effect of air pollution. However, in this case, as the entire system becomes complicated, and as the size of the entire system increases, there is a limit to the installation space in the vehicle, and the weight of the entire system increases, worsening fuel economy, and the overall production cost increases. .

In particular, the main material of the carrier for supporting the catalytic material used in the existing after-treatment apparatus is using a ceramic material such as cordierite and silicon carbide. However, conventional ceramic carriers have a low coefficient of thermal expansion, and thus have excellent thermal shock resistance, but overall, they have low physical impact strength and are easily broken, and since the thermal capacity is high, the temperature does not rise quickly in the low temperature section, thereby purifying exhaust gas in this section. This has the disadvantage of being lowered.

Embodiments of the present invention provide an integrated exhaust aftertreatment apparatus using a metal fiber carrier that can integrally constitute various types of exhaust aftertreatment apparatuses for removing harmful substances in exhaust gas generated in an internal combustion engine.

In addition, the embodiment of the present invention, using a metal fiber carrier that can implement the simplification, miniaturization, light weight and reduction of production cost while having a high purification efficiency in order to fully satisfy the strengthening of vehicle emission regulations after EURO-6 Provide an integrated exhaust aftertreatment device.

In addition, the embodiment of the present invention, by using a metal fiber carrier formed of metal fibers can solve the disadvantages of the existing ceramic carriers and the existing metal carriers, and to reduce the loss of supporting precious metals by supporting the catalyst on the metal fiber carriers Provided is an integrated exhaust aftertreatment apparatus using a metal fiber carrier.

According to an embodiment of the present invention, an exhaust pipe connected to the internal combustion engine to exhaust the first exhaust gas generated in the internal combustion engine, and connected to the exhaust pipe to receive the first exhaust gas from the exhaust pipe, are lean. Selective Catalytic Reduction Filter (SRF), and Selective Reduction Catalyst Filter for reducing and removing nitrogen oxides in the first exhaust gas and collecting and removing particulate matter in the first exhaust gas under an air-fuel ratio operating condition. Connected to the selective reduction catalyst filter so as to receive the first purified exhaust gas at and absorbing nitrogen oxides in the second exhaust gas under lean fuel consumption operation conditions, and then removing nitrogen oxides under temporary concentrating fuel efficiency operation conditions, and lean. By oxidizing hydrocarbons, carbon monoxide, ammonia, etc. In addition, and also to provide the second removing and collecting a particulate matter in the nitrogen oxide storage catalyst in the exhaust gas to the filter and then integrated exhaust using a metal carrier body comprising a fiber (LTF, Lean NOx Trap Filter) processing apparatus.

Therefore, in the present embodiment, by integrally configuring the selective reduction catalyst filter and the nitrogen oxide storage catalyst filter, it is possible to increase the purification efficiency more than simple combination of existing LNT, SCR, DPF, etc., simplifying the overall structure And miniaturization can also be realized.

According to one aspect, the selective reduction catalyst filter and the nitrogen oxide storage catalyst filter may be a filter-type metal fiber carrier formed of metal fibers.

The filter-type metal fiber carrier may be formed of a pleated woven or nonwoven fabric made of the metal fiber.

The filter-type metal fiber carrier may be processed into shapes corresponding to internal spaces of the selective reduction catalyst filter and the nitrogen oxide storage catalyst filter, respectively, and the pressure and particulate matters of the first exhaust gas and the second exhaust gas. The thickness or overlapping shape can be determined according to the removal efficiency of the material.

The filter-type metal fiber carrier may include aluminum in the metal fiber to form an alumina oxide film on the surface of the metal fiber when the metal fiber is heat-molded. The alumina oxide film as described above may be supported with a catalyst.

According to one aspect, the selective reduction catalyst filter and the nitrogen oxide storage catalyst filter, it may be formed integrally connecting the gas outlet of the selective reduction catalyst filter and the gas inlet of the nitrogen oxide storage catalyst filter.

According to one aspect, the integrated exhaust after-treatment apparatus according to an embodiment of the present invention, the first exhaust gas to be disposed in the front of the selective reduction catalyst filter or the exhaust pipe and used for the reduction of the nitrogen oxides Reducing agent injection module for injecting a reducing agent may be further included.

In addition, the integrated exhaust after-treatment apparatus according to an embodiment of the present invention, disposed on the front portion of the selective reduction catalyst filter or the exhaust pipe and the fuel to the first exhaust gas to change the air-fuel ratio of the first exhaust gas It may further include a fuel injection module for injecting.

Integrated exhaust after-treatment apparatus using a metal fiber carrier according to an embodiment of the present invention, since the selective reduction catalyst filter and the nitrogen oxide storage catalyst filter is formed in an integrated structure sequentially connected to the exhaust pipe connected to the internal combustion engine, the internal combustion engine It is possible to more effectively remove the harmful substances contained in the exhaust gas generated in the to increase the purification efficiency, and can fully respond to the regulation of automobile emissions after EURO-6.

In addition, the integrated exhaust aftertreatment apparatus using the metal fiber carrier according to the present embodiment, TWC (three-way catalyst), OC (oxidation catalyst), PF (particulate matter) used separately according to the exhaust conditions and the type of harmful substances to be removed It is a structure that integrates functions such as collector, selective reduction catalyst (SCR), and NOx storage catalyst (LNT) into a single block, so that the entire system can be simplified, miniaturized, lightweight, and reduced production costs.

In addition, the integrated exhaust post-treatment apparatus using a metal fiber carrier according to an embodiment of the present invention, by placing a filter-type metal fiber carrier formed of metal fibers in the selective reduction catalyst filter and the nitrogen oxide storage catalyst filter was used previously The problem of the metal carrier formed of the ceramic carrier or the metal sheet can be improved, and the size of the integrated exhaust post-treatment device can be greatly reduced by reducing the size of the filter-type metal fiber carrier than the ceramic carrier and the metal carrier.

In addition, the integrated exhaust post-treatment apparatus using a metal fiber carrier according to an embodiment of the present invention, because it uses a filter-type metal fiber carrier formed of metal fibers instead of the conventional ceramic carrier, it is caused by an external impact like a ceramic carrier Since the risk of breakage is lowered and the heat transfer rate is higher than that of the ceramic carrier, the heat capacity of the filter-type metal fiber carrier is lower than that of the ceramic carrier, so that the purification efficiency of nitrogen oxide can be sufficiently secured even at a low exhaust temperature.

In addition, the integrated exhaust post-treatment apparatus using a metal fiber carrier according to an embodiment of the present invention, since the filter-type metal fiber carrier formed of metal fibers instead of the plate-shaped metal carrier used in the past, the metal carrier in the shape of a metal sheet As a result, shrinkage, expansion, and deformation due to temperature change are not severely issued, and as a result, the metal fiber carrier is more durable than the metal carrier because it can prevent damage and detachment of the wash coat. Can be excellent.

In addition, the integrated exhaust post-treatment apparatus using a metal fiber carrier according to an embodiment of the present invention, by forming the filter-type metal fiber carrier in a pleated non-woven or woven fabric in the interior space of the selective reduction catalyst filter and the nitrogen oxide storage catalyst filter Since the structure is arranged, it is possible to further increase the collection efficiency of particulate matter in the process of passing the exhaust gas through the filter-type metal fiber carrier, thereby maximizing the removal efficiency of particulate matter contained in the exhaust gas.

In addition, since the integrated exhaust post-treatment apparatus using the metal fiber carrier according to the embodiment of the present invention has a structure in which a catalyst is supported on the alumina oxide film of the filter-type metal fiber carrier, when the wash coating is performed compared to the ceramic carrier used in the past, The adhesion can act strongly, thus increasing the adhesion of the catalyst over the ceramic carrier. Therefore, the filter-type metal fiber carrier according to the present embodiment can significantly reduce the loss of noble metals, and can prevent the deterioration of the purification performance even if the amount of the catalyst supported by the conventional ceramic carrier is reduced.

In addition, the integrated exhaust post-treatment apparatus using the metal fiber carrier according to the embodiment of the present invention, by maximizing the efficiency of purification of harmful substances and the size of the filter-type metal fiber carrier by using the filter-type metal fiber carrier Even if the deterioration of the purification performance can be prevented, the size and weight of the integrated exhaust aftertreatment device can be significantly reduced compared to the structure using the conventional ceramic carrier or metal carrier, and accordingly the design of the integrated exhaust aftertreatment device In addition to improving the conditions, it is possible to free up installation space.

1 is a view schematically showing an integrated exhaust aftertreatment apparatus using a metal fiber carrier according to an embodiment of the present invention.
FIG. 2 is a view schematically showing a filter-type metal fiber carrier disposed inside the selective reduction catalyst filter and the nitrogen oxide storage catalyst filter shown in FIG. 1.
3 is a cross-sectional view taken along line AA of FIG. 2.
4 is a view showing the metal fiber carrier shown in FIGS. 2 and 3.
5 is an enlarged view of the surface of the metal fiber carrier shown in FIG.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to or limited by the embodiments. Like reference symbols in the drawings denote like elements.

1 is a view schematically showing an integrated exhaust aftertreatment apparatus 100 using a metal fiber carrier according to an embodiment of the present invention.

1, the integrated exhaust after-treatment apparatus 100 using a metal fiber carrier according to an embodiment of the present invention is an exhaust pipe 110, Selective Catalytic Reduction Filter (SRF) 120, And a lean NOx trap filter (LTF) 130.

The exhaust pipe 110 is a device for guiding the exhaust gas to the outside to exhaust the exhaust gas generated by the engine 10 of the internal combustion engine. The exhaust pipe 110 as described above may be connected to the engine 10 of the internal combustion engine.

On the exhaust pipe 110, the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130 may be sequentially disposed along the longitudinal direction of the exhaust pipe 110. Hereinafter, for convenience of description of the present invention, the flow direction of the exhaust gas flowing along the exhaust pipe 110 is defined as the rear, and the direction opposite to the flow direction of the exhaust gas is defined as the front. In the present embodiment, the selective reduction catalyst filter 120 may be disposed in front of the nitrogen oxide storage catalyst filter 130.

Referring to FIG. 1, the selective reduction catalyst filter 120 combines the functions of the SCR and the DPF. That is, the selective reduction catalyst filter 120 simultaneously removes nitrogen oxides (NOx) and particulate matter (PM) from the harmful substances contained in the first exhaust gas G1 discharged from the engine 10 of the internal combustion engine. Function can be performed.

Meanwhile, the selective reduction catalyst filter 120 may be connected to the exhaust pipe 110 to receive the first exhaust gas G1 discharged from the engine 10 of the internal combustion engine through the exhaust pipe 110.

The selective reduction catalyst filter 120 as described above may reduce and remove nitrogen oxides from harmful substances contained in the first exhaust gas G1 under lean fuel efficiency operating conditions, and at the same time, the first exhaust gas G1 may be reduced. Particulate matter can be collected and removed from the harmful substances contained in.

Specifically, the selective reduction catalyst filter 120 may selectively purify by reacting nitrogen oxide with ammonia, which is a reducing agent, under exhaust gas lean conditions, as well as collecting and burning particulate matter as a primary.

For example, the selective reduction catalyst filter 120 may be formed in a structure having a filter-type metal fiber carrier 122 described later inside the body 124 of the metal pipe shape. The filter metal fiber carrier 122 as described above may be supported with a catalyst capable of reducing nitrogen oxides.

Therefore, the selective reduction catalyst filter 120 injects a reducing agent into the first exhaust gas G1 in the lean air-fuel condition to reduce nitrogen oxide, and at the same time filters the particulate matter through the filter structure of the filter metal fiber carrier 122. Can be removed by burning.

Referring to FIG. 1, the nitrogen oxide storage catalyst filter 130 is a device having a function of LNT that has been used in the past. That is, the nitrogen oxide storage catalyst filter 130 may remove nitrogen oxides (NOx), particulate matter (PM), and the like from the harmful substances included in the second exhaust gas G2 purified first from the selective reduction catalyst filter 120. The car can be removed at the same time.

On the other hand, the nitrogen oxide storage catalyst filter 130 may be connected to the rear portion of the selective reduction catalyst filter 120 to receive the first purified second exhaust gas (G2) from the selective reduction catalyst filter 120, the second The third exhaust gas G3 obtained by purifying the exhaust gas G2 may be formed to be discharged to the outside air.

As described above, the nitrogen oxide storage catalyst filter 130 may absorb nitrogen oxides from harmful substances included in the second exhaust gas G2 under lean fuel efficiency operation conditions, and then remove nitrogen oxides under temporary excessive fuel efficiency operation conditions. At the same time, hydrocarbons, carbon monoxide, ammonia, and the like may be oxidized and removed under lean fuel economy operating conditions, and particulate matter may be collected and removed from the harmful substances included in the second exhaust gas G2.

Specifically, the nitrogen oxide storage catalyst filter 130 may not only oxidize hydrocarbons and carbon monoxide under conditions where exhaust gas is lean, but may also collect and purify nitrogen oxides, and then purify them to a transiently concentrated state. Particulate matter can be collected and burned secondarily.

For example, the nitrogen oxide storage catalyst filter 130 may also be formed in a structure having a filter-type metal fiber carrier 122 described later inside the metal pipe-shaped body 124 like the selective reduction catalyst filter 120. Can be. The filter metal fiber carrier 122 as described above may support a catalyst and a noble metal catalyst capable of occluding nitrogen oxides.

Accordingly, the nitrogen oxide storage catalyst filter 130 occludes the nitrogen oxide passed through the selective reduction catalyst filter 120 in the rare lean fuel ratio condition while being not reduced, and oxidizes and removes unburned hydrocarbon, carbon monoxide, ammonia, and particulate matter. can do. In addition, the nitrogen oxide storage catalyst filter 130 may be removed by reacting the nitrogen oxide detached from the transient super-fuel fuel condition with unburned hydrocarbon, carbon monoxide, ammonia, and particulate matter.

As shown in FIG. 1, in this embodiment, the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130 may be integrally formed. That is, the gas outlet of the selective reduction catalyst filter 120 and the gas inlet of the nitrogen oxide storage catalyst filter 130 are integrally connected, and the metal pipes of the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130 are integrated. Shaped body 124 may be integrally formed. However, the present invention is not limited thereto, and the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130 may be separately disposed at different positions of the exhaust pipe 110.

Referring to FIG. 1, the integrated exhaust aftertreatment apparatus 100 according to an embodiment of the present invention may further include a reducing agent injection module 140 and a fuel injection module 150.

Here, the reducing agent injection module 140 is a device for injecting the reducing agent used for the reducing action of the nitrogen oxide in the selective reduction catalyst filter 120 to the first exhaust gas (G1). The reducing agent injection module 140 may be disposed in front of the selective reduction catalyst filter 120 or the exhaust pipe 110. Hereinafter, although the reducing agent injection module 140 is described as being disposed in the exhaust pipe 110 in the present embodiment, the present invention is not limited thereto and may be disposed directly in the front portion of the body 124 of the selective reduction catalyst filter 120. .

By adjusting the operation of the reducing agent injection module 140 as described above, it is possible to effectively maximize the function of the selective reduction catalyst filter 120. The reducing agent injection module 140 may inject urea water and fuel capable of generating a reducing agent such as ammonia NH or hydrocarbon HC to the first exhaust gas G1.

In addition, the fuel injection module 150 is a device for injecting fuel to the first exhaust gas G1 in order to change the air-fuel ratio of the first exhaust gas G1. The fuel injection module 150 may be disposed at the front of the selective reduction catalyst filter 120 or the exhaust pipe 110, like the reducing agent injection module 140. Hereinafter, the fuel injection module 150 is described as being disposed at a position spaced apart from the reducing agent injection module 140 in the exhaust pipe 110, but is not limited thereto. The body of the selective reduction catalyst filter 120 It may be disposed directly at the front of the 124 or integrally formed with the reducing agent injection module 140.

By adjusting the operation of the fuel injection module 150 as described above, it is possible to effectively maximize the function of the nitrogen oxide storage catalyst filter 130. The fuel injection module 150 may inject a fuel capable of changing the air-fuel ratio of the exhaust gas to the first exhaust gas G1.

In addition, in the present embodiment, a heating device for heating the first exhaust gas G1 may be installed in the exhaust pipe 110. The heating apparatus as described above may heat the first exhaust gas G1 such that the temperature of the first exhaust gas G1 has a set value or more.

FIG. 2 is a view schematically showing a filter metal fiber carrier 122 disposed inside the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130 shown in FIG. 1, and FIG. It is a figure which shows the cross section along the AA line shown. 4 is a view illustrating the filter-type metal fiber carrier 122 shown in FIGS. 2 and 3, and FIG. 5 is an enlarged view of the surface of the metal-fiber carrier 122 shown in FIG. 4.

2 to 5, the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130 of the integrated exhaust aftertreatment device 100 according to the embodiment of the present invention are formed of metal fibers (F). The filter metal fiber carrier 122 may be disposed.

The filter-type metal fiber carrier 122 may be formed of a pleated woven or nonwoven fabric made of metal fiber (F).

Here, the metal fiber F may be formed with a micro-scale wire diameter (average of 50 μm or less). When the filter-type metal fiber carrier 122 is formed of a very thin metal fiber (F) as described above, the specific surface area of the carrier on which the catalyst is coated is greatly increased, so that the plate-shaped metal carrier (metel sheet) formed in the same volume and thickness. The surface area can be increased by more than two times. Therefore, the filter-type metal fiber carrier 122 according to the present embodiment may carry more catalyst than the metal carrier of the same size.

In addition, the filter-type metal fiber carrier 122 may be used by processing in the form of a thin thread of a metal material and then reworked in the form of a woven or nonwoven fabric. Hereinafter, in this embodiment, the filter-type metal fiber carrier 122 will be described as being formed of a pleated nonwoven fabric of the metal fiber (F).

The metal fiber (F) of the filter-type metal fiber carrier 122 as described above may be formed of an alumina oxide film on its surface as an alloy of iron (Fe), chromium (Cr), and aluminum (Al). That is, since the metal fiber (F) of the filter-type metal fiber carrier 122 includes aluminum, an alumina oxide film may be formed on the surface of the metal fiber (F) during the heat molding of the metal fiber (F), and the metal fiber The catalyst may be supported on the alumina oxide film of (F). The filter-type metal fiber carrier 122 may not be oxidized by an alumina oxide film and its durability may be improved to 10 years or more. In particular, since the alumina oxide film is the same component as the catalyst support, the filter-type metal fiber carrier 122 may exhibit a much better result in the adhesion test than the ceramic carrier due to the strong adhesive force during washcoat coating.

On the other hand, the biggest disadvantage of the conventional flat metal sheet (Metal sheet) was a problem that the washcoat does not last long and fall off the carrier and low durability. Specifically, the conventional flat metal carrier can prevent the washcoat from falling down due to severe shrinkage and expansion and severe deformation due to the characteristics of the metal having a thermal expansion coefficient 16 times higher than that of ceramics and the continuous structural structure. There was no. However, the filter-type metal fiber carrier 122 according to the present embodiment has the advantage that the washcoat does not easily fall off because each fiber contracts or expands to the surrounding space independently by using a fibrous carrier.

Figure 4 shows an example of the structure of the filter-type metal fiber carrier 122 made of a nonwoven fabric of the metal fiber in the form of wrinkles, Figure 5 is a surface of the filter-type metal fiber carrier 122 shown in FIG. An enlarged non-woven form of metal fiber F is shown.

That is, the pleated nonwoven fabric made of the metal fibers (F) may be made of a thin metal yarn having a diameter of about 50 μm, and the metal yarn may contain aluminum, so that an alumina oxide film may be formed on the surface after heat forming. If the alumina oxide film as described above is calcined by supporting the noble metal catalyst and the promoter according to the use, a catalyst having a relatively large specific surface area can be made.

2 and 3, the filter-type metal fiber carrier 122 according to the present embodiment has a shape corresponding to the internal space of the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130. Each may be processed, and a thickness or an overlapping shape may be determined according to the pressure of the first exhaust gas G1 and the second exhaust gas G2 and the removal efficiency of particulate matter.

For example, since the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130 include the same metal pipe-shaped body 124, the filter-type metal fiber carrier 122 is a metal pipe-shaped body 124 It is formed in a cylindrical shape that is accommodated in the interior of the can be disposed on the inner peripheral surface of the body (124). That is, the filter-type metal fiber carrier 122 is made of a nonwoven fabric of the metal fiber (F) in the form of pleats, overlapping to a desired thickness, and made into a cylindrical shape corresponding to the metal pipe-shaped body 124 to fix both ends Can be. The filter-type metal fiber carrier 122 as described above may appropriately adjust the number overlapping the thickness of the carrier in order to control the pressure of the exhaust and the purification efficiency of the particulate matter.

As shown in FIG. 2 and FIG. 3, in the present embodiment, the filter-type metal fiber carrier 122 is formed in a hollow cylindrical shape, and includes the harmful substances contained in the first and second exhaust gases G1 and G2. It will be described as being disposed in a double structure inside the body 124 to increase the purification efficiency.

That is, the filter-type metal fiber carrier 122 includes a first metal fiber carrier 122a formed in a hollow cylindrical shape disposed on an inner circumferential surface of the metal pipe-shaped body 124, and a first metal fiber carrier 122a. It may be provided with a second metal fiber carrier 122b formed in a hollow cylindrical shape disposed on the inner peripheral surface of the hollow portion of. The second metal fiber carrier 122b may be formed to have a smaller diameter than the first metal fiber carrier 122a. Accordingly, the first and second exhaust gases G1 and G2 flow into the hollow portion of the second metal fiber carrier 122b and then pass through the wall surfaces of the second metal fiber carrier 122b and the first metal fiber carrier 122a. Can flow into the path.

At this time, the particulate matter contained in the first and second exhaust gases G1 and G2 may be filtered while passing through the wall surface of the filter metal fiber carrier 122, and the gaseous substance may be filtered through the filter metal fiber carrier 122. With the help of catalysts supported on it, oxidation and reduction reactions can be carried out and removed.

Looking at the operation and effect of the integrated exhaust after-treatment apparatus 100 using a metal fiber carrier according to an embodiment of the present invention configured as described above are as follows.

When the engine 10 of the internal combustion engine operates, the first exhaust gas G1 generated by the engine 10 of the internal combustion engine flows along the exhaust pipe 110 in a direction in which it is discharged to the outside.

In this case, the reducing agent injection module 140 selectively injects a suitable amount of the reducing agent to the first exhaust gas G1 flowing along the exhaust pipe 110, and the fuel injection module 150 flows along the exhaust pipe 110. A suitable amount of fuel is selectively injected into the first exhaust gas G1 to be used.

If the heating device is disposed in the exhaust pipe 110, the first exhaust gas G1 is heated to a set temperature or higher at the initial stage of operation of the engine 10. Therefore, the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130 may further promote an oxidation reaction or a reduction reaction for removing the harmful substances contained in the first exhaust gas G1.

The exhaust pipe 110 guides the first exhaust gas G1 to the selective reduction catalyst filter 120. In the selective reduction catalyst filter 120, harmful substances of the first exhaust gas G1 are formed by the filter metal fiber carrier 122 while the first exhaust gas G1 passes through the filter metal fiber carrier 122. Primary purification.

Specifically, the selective reduction catalyst filter 120 firstly removes nitrogen oxides and particulate matters from harmful substances included in the first exhaust gas G1 under lean fuel efficiency operating conditions. That is, under the lean fuel economy operating condition, the selective reduction catalyst filter 120 reacts nitrogen oxide with a reducing agent among the harmful substances contained in the first exhaust gas G1 to remove nitrogen oxide firstly, and also to remove the first exhaust gas G1. Among the harmful substances included in the), particulate matter is collected in the filter-type metal fiber carrier 122 and then burned to first remove the particulate matter.

As described above, the second exhaust gas G2 purified by the selective reduction catalyst filter 120 flows to the nitrogen oxide storage catalyst filter 130 and is disposed inside the nitrogen oxide storage catalyst filter 130. In the course of passing through the filter metal fiber carrier 122, the harmful substances contained in the second exhaust gas G2 are again purged again.

Specifically, the nitrogen oxide storage catalyst filter 130 absorbs nitrogen oxides from the harmful substances contained in the second exhaust gas G2 under lean fuel efficiency operating conditions, and also removes hydrocarbons, carbon monoxide, ammonia, and particulate matter. Secondary removal of nitrogen oxides occluded under transient superfuel operating conditions. That is, in the lean fuel efficiency operating condition, the nitrogen oxide storage catalyst filter 130 further occludes nitrogen oxides among the harmful substances contained in the second exhaust gas G2, as well as contained in the second exhaust gas G2. Hydrocarbons, carbon monoxide, ammonia, and the like are oxidized and removed, and particulate matter is collected in the filter-type metal fiber carrier 122 from the harmful substances contained in the second exhaust gas G2 and then burned to remove the secondary material. In addition, when temporarily changed to the super-fuel fuel efficiency operating conditions, the nitrogen oxide storage catalyst filter 130 is desorbed in the lean air-fuel operating conditions, and then reacted with unburned hydrocarbons, carbon monoxide, ammonia, and particulate matter in a secondary manner. Remove

As described above, the third exhaust gas G3 purified second by the nitrogen oxide storage catalyst filter 130 is discharged to the outside air. Since the third exhaust gas G3 is purified twice by the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130, the third exhaust gas G3 contains almost no harmful substances. It can cope with the recent tightening emission regulations.

Exhaust after-treatment system of the existing EURO-6 diesel vehicle is a combination of LNT to reduce nitrogen oxides and DPF to reduce particulate matter, or a combination of SCR and DPF. However, after EURO-6, which is further strengthened in automobile emission regulations, it is expected that only LNT, SCR and DPF can be used to meet nitrogen oxide and particulate matter emission regulations.

In addition, in order to improve fuel efficiency and meet the total CO2 emission regulations, the weight of all the parts of the vehicle can be reduced and simplified as much as possible. When the exhaust system such as LNT, SCR, and DPF is installed, the entire system becomes very complicated. Increasing weight will also lead to lower fuel economy.

In order to solve the above problems, research has been continued to simplify by integrating oxidizing catalysts and reduction catalysts which are used separately. In the present embodiment, the nitrogen oxide storage catalyst filter 130 and the noble metal oxidation catalyst material and selective reduction catalyst material capable of reducing nitrogen oxides by controlling the transient excess air-fuel ratio while having the same function as DOC in the air-fuel ratio is lean, particulate matter. The selective reduction catalyst filter 120 capable of oxidizing the material and injecting urea water, which is a reducing agent, to reduce nitrogen oxides is integrated in the exhaust pipe 110, thereby simply combining existing LNT, SCR, DPF, and the like. The exhaust gas purification efficiency is higher, and the overall system can be simplified, downsized, lightened and reduced in production costs.

On the other hand, if the existing ceramic carrier is used in the selective reduction catalyst filter 120 and the nitrogen oxide storage catalyst filter 130, due to the characteristics of the ceramic material, the size and weight of the integrated exhaust aftertreatment apparatus 100 increases proportionally. In the case of the selective reduction catalyst filter 120, the inlet and outlet of each hole is a filter in which one side is blocked in a lattice form, and the exhaust gas passes through the pores of the wall. Will also increase.

In this embodiment, by employing the filter-type metal fiber carrier 122 formed of metal fibers (F) instead of the ceramic carrier, not only can the regeneration performance of particulate matter be improved, but also the NOx storage performance can be improved at low temperatures. The purification efficiency of the harmful substances contained in the exhaust gas can be greatly increased.

Specifically, using the filter-type metal fiber carrier 122 having a low heat capacity, it is possible to easily obtain a temperature suitable for the oxidation reaction or the reduction reaction even in the engine operating section with a low exhaust temperature to improve the purification performance of the nitrogen oxide, metal Since the nonwoven fabric of the fiber is formed in the form of wrinkles it can effectively remove the particulate matter.

Here, at the initial start of the engine, since some time is required until the exhaust temperature reaches the catalytic activity temperature, it is necessary to forcibly raise the exhaust temperature or to collect harmful substances exiting. For example, a method of forcibly raising the exhaust temperature includes installing an electric heater or attaching an additional combustor.

In addition, LNT is one of the most effective low-temperature NOx removal methods after collecting NOx and reaching the activation temperature in this low temperature range, but LNT also needs energy to capture NOx, so if possible I need a way to speed up the process. Accordingly, when the filter-type metal fiber carrier 122 using the metal fiber F having a specific heat of about 50% lower than that of the ceramic and having a thermal conductivity of 13 times higher is used in the nitrogen oxide storage catalyst filter 130, the nitrogen at the initial start of the engine is reduced. Since the activation temperature of the oxide storage catalyst filter 130 can be quickly increased, the NOx removal efficiency at low temperature can be effectively increased.

In addition, the filter-type metal fiber carrier 122 has a structure in which a catalyst is supported on a cylindrical fiber carrier, so that the precious metal carrying loss can be reduced as compared with the precious metal carrying loss occurring at the cell edge of the ceramic carrier, and thus the ceramic carrier. By reducing the amount of catalyst to be loaded, the production cost of the filter-type metal fiber carrier can be lowered by 10% or more.

As described above, the integrated exhaust after-treatment apparatus 100 according to the embodiment of the present invention, TWC (three-way catalyst), OC (oxidation catalyst), PF which are divided according to the exhaust conditions and the type of harmful exhaust gas for removal, (Particulate Collector), SCR (Selective Reduction Catalyst), LNT (NOx Absorption Catalyst), etc., integrating the functions into one, and using the filter-type metal fiber carrier 122, simplifying, miniaturizing and reducing the overall system Production cost savings can be achieved.

Although the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And various modifications and changes may be made thereto without departing from the scope of the present invention. Therefore, the spirit of the present invention should not be limited to the described embodiments, and all the things that are equivalent to or equivalent to the claims as well as the following claims will belong to the scope of the present invention.

10: engine of internal combustion engine
100: integrated exhaust aftertreatment device
110: Exhaust pipe
120: selective reduction catalyst filter
122: filter type metal fiber carrier
124 body
130: nitrogen oxide absorption catalyst filter
140: reducing agent injection module
150: fuel injection module
F: metal fiber
G1: first exhaust gas
G2: second exhaust gas
G3: third exhaust gas

Claims (8)

An exhaust pipe connected to the internal combustion engine to exhaust the first exhaust gas generated in the internal combustion engine;
It is connected to the exhaust pipe to receive the first exhaust gas from the exhaust pipe, and reduces and removes nitrogen oxides in the first exhaust gas under lean air-fuel operating conditions, and collects and removes particulate matter in the first exhaust gas. A selective reduction catalyst filter; And
The selective reduction catalyst filter is connected to the selective reduction catalyst filter so as to receive the first purified exhaust gas, and occludes nitrogen oxides in the second exhaust gas under lean air fuel operating conditions. A nitrogen oxide storage catalyst filter which removes nitrogen oxides, oxidizes and removes hydrocarbons, carbon monoxide, ammonia, etc. under lean fuel efficiency operating conditions, and collects and removes particulate matter in the second exhaust gas;
Integrated exhaust post-treatment apparatus using a metal fiber carrier comprising a. The method of claim 1,
The selective reduction catalyst filter and the nitrogen oxide storage catalyst filter is integrated exhaust post-treatment apparatus using a metal fiber carrier, characterized in that the filter-type metal fiber carrier formed of metal fibers are disposed. 3. The method of claim 2,
The filter-type metal fiber carrier, integrated exhaust after-treatment apparatus using a metal fiber carrier, characterized in that formed of pleated woven or non-woven fabric made of the metal fiber. The method of claim 3,
The filter-type metal fiber carrier is processed into a shape corresponding to an inner space of the selective reduction catalyst filter and the nitrogen oxide storage catalyst filter, respectively, and the pressures of the first exhaust gas and the second exhaust gas and the particulate matter Integrated exhaust post-treatment apparatus using a metal fiber carrier, characterized in that the thickness or overlapping shape is determined according to the removal efficiency. The method of claim 3,
The filter-type metal fiber carrier may include aluminum in the metal fiber to form an alumina oxide film on the surface of the metal fiber during the heat molding of the metal fiber, and a metal fiber in which the catalyst is supported on the alumina oxide film. Integrated exhaust post-treatment device using a carrier. The method according to any one of claims 1 to 5,
The selective reduction catalyst filter and the nitrogen oxide storage catalyst filter are integrally exhausted using a metal fiber carrier, wherein the gas outlet of the selective reduction catalyst filter and the gas inlet of the nitrogen oxide storage catalyst filter are integrally connected to each other. Aftertreatment device. The method according to any one of claims 1 to 5,
The metal fiber carrier further comprises a reducing agent injection module disposed in the front of the selective reduction catalyst filter or the exhaust pipe, and injecting a reducing agent into the first exhaust gas for use in the reducing action of the nitrogen oxides. Integrated exhaust post-processing device using. The method of claim 7, wherein
The metal fiber further comprises a fuel injection module disposed in the front portion of the selective reduction catalyst filter or the exhaust pipe and injecting fuel into the first exhaust gas to change the air-fuel ratio of the first exhaust gas. Integrated exhaust post-treatment device using a carrier.

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