EXHAUST GAS REDUCTION DEVICE INCLUDING ELECTRICALLY HEATED CATALYST-COATED PARTICULATE FILTER

Description

TECHNICAL FIELD

The present invention relates to an exhaust gas reduction device including an electrically heatable catalyst-coated particulate filter, and more particularly, the present disclosure relates to an exhaust gas reduction device including an electrically heated catalyst-coated particulate filter configured to reduce HC and NOx discharged during a cold start of a vehicle, with a structure in which an electric heater and a catalyst-coated filter are combined.

BACKGROUND ART

Conventionally, only a three-way catalyst converter (TWC) has been used to reduce an exhaust gas of a gasoline engine, but recently, in order to satisfy the strengthened discharge of particulate matter (PM) and gaseous harmful gases (HC, CO, NOx) allowance reference, a device that connects an electrically heated catalyst (EHC) 10, a three-way catalyst (TWC) 20, and a gasoline particulate filter (GPF) 30 as shown in FIG. 1 is being developed.

However, such a device has a drawback in that it has a large volume as it includes the EHC 10, the TWC 20, and the GPF 30.

The conventional EHC 10 is used to rapidly heat a three-way catalyst during initial cold start of the engine. However, the conventional EHC 10 is a vortex-shaped electrical heater, and since the conventional EHC 10 has a large number of small ceramic rods installed in a middle to prevent a short circuit, its structure is complex, while making it difficult to manufacture and vulnerable to vibration.

In addition, a catalyst coating is applied directly to the EHC 10 to improve the effect of an exhaust gas reduction, but when power is applied to the EHC 10, the temperature rises very high. In this case, the EHC 10 has a large thermal expansion rate, whereas the coating material of the ceramic material has a small thermal expansion rate, and thus there is a problem of damage due to thermal impact.

In addition, since the TWC 20 is disposed behind the EHC 10, there is also a problem that heat transfer is not fast and auxiliary air must be supplied to heat the three-way catalyst with an electric heater before starting the engine.

Many inventors are conducting extensive research to solve this problem, but satisfactory results have not yet been achieved.

DISCLOSURE

Technical Problem

The technical object of an exhaust gas reduction device including an electrically heated catalyst-coated particulate filter according to embodiments of the present invention is to provide an exhaust gas reduction device that can rapidly reduce HC and NOx discharged during a cold start of a vehicle.

Another technical object of the exhaust gas reduction device including an electrically heated catalyst-coated particulate filter according to embodiments of the present invention is to provide an exhaust gas reduction device having a simplified and miniaturized structure and improved durability performance.

The technical objects of the exhaust gas reduction device including the electrically heated catalyst-coated particulate filter according to the embodiments of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by a person skilled in the art from the description below.

Technical Solution

A filter unit structure according to an embodiment is a filter unit structure used in an exhaust gas reduction device and may include: a ceramic filter structure formed to filter a particulate material; a first electrical heating plate disposed on one side of the ceramic filter structure to generate heat; and a second electrical heating plate disposed on the other side of the ceramic filter structure to generate heat.

The ceramic filter structure may include a ceramic filter plate, and a gas inlet may be formed at one end of the ceramic filter plate to allow an exhaust gas to flow.

A first electrical heating plate or a second electrical heating plate may be designed such that a current is supplied in parallel.

An exhaust gas inflowed through the gas inlet may be configured to move through the first electrical heating plate or the second electrical heating plate.

The first electrical heating plate or the second electrical heating plate includes a central region and an outer region, and the amount of exhaust gas passing through the central region may be different from the amount of exhaust gas passing through the outer region.

The first electrical heating plate or the second electrical heating plate includes a plurality of air passages through which exhaust gas passes, and a diameter of the plurality of air passages may be 0.1 mm or less.

The filter unit structure may further include a second ceramic filter plate fixed to the ceramic filter plate with the first electrical heating plate or the second electrical heating plate interposed therebetween, and a gas outlet may be formed at one end of the second ceramic filter plate such that the exhaust gas passing through the first electrical heating plate or the second electrical heating plate is discharged.

A filter unit structure according to an embodiment is a filter unit structure used in an exhaust gas reduction device, and a ceramic filter structure may include: a ceramic insulator; a first filter plate disposed between the ceramic insulator and the first electrical heating plate; and a second filter plate disposed between the ceramic insulator and the second electrical heating plate, wherein one end of the ceramic insulator is provided with a gas inlet configured to allow an exhaust gas to flow into it.

The first filter plate and the second filter plate may be coated with a catalyst.

An exhaust gas inflowed through the gas inlet may be configured to move through the first filter plate and the first electrical heating plate, or through the second filter plate and the second electrical heating plate.

The first electrical heating plate or the second electrical heating plate includes a central region and an outer region, and the amount of exhaust gas passing through the central region may be different from the amount of exhaust gas passing through the outer region.

The first electrical heating plate or the second electrical heating plate includes a plurality of air passages through which exhaust gas passes, and a diameter of the plurality of air passages may be 0.1 mm or less.

Electrical resistance of the first electrical heating plate may be smaller than electrical resistance of the first filter plate, and electrical resistance of the second electrical heating plate may be smaller than electrical resistance of the second filter plate.

The filter unit structure may further include a second ceramic filter structure fixed to the ceramic filter structure with the first electrical heating plate or the second electrical heating plate in between, the second ceramic filter structure includes a second ceramic insulator, and a gas outlet may be formed at one end of the second ceramic insulator such that an exhaust gas passing through the first electrical heating plate or the second electrical heating plate is discharged.

A filter unit structure according to an embodiment is a filter unit structure used in an exhaust gas reduction device, and may include: a catalyst-coated ceramic filter plate; a first electrical heating plate disposed on one side of the ceramic filter plate to generate heat; and a second electrical heating plate disposed on the other side of the ceramic filter structure to generate heat, wherein the ceramic filter plate may be connected to the first electrical heating plate by ceramic bonding, and the ceramic filter plate may be connected to the second electrical heating plate by ceramic bonding.

A particulate filter according to an embodiment includes: a first filter unit structure; and a second filter unit structure, wherein first filter unit structure and the second filter unit structure may be stacked and connected.

At least one of the first filter unit structure and the second filter unit structure may include: a ceramic filter structure formed to filter a particulate material; a first electrical heating plate disposed on one side of the ceramic filter structure to generate heat; and a second electrical heating plate disposed on the other side of the ceramic filter structure to generate heat, and a gas flow path through which an exhaust gas flows may be formed at one end of the ceramic filter structure.

The gas flow path of the first filter unit structure may be disposed at the opposite end of the gas flow path of the second filter unit structure.

A particulate filter according to an embodiment may include: a gas inlet formed to allow a gas to inflow; a first electrical heating plate disposed on a first side to generate heat; and a second electrical heating plate disposed on a second side opposite the first side to generate heat, wherein the first electrical heating plate and the second electrical heating plate may be connected by a ceramic insulator and configured to form an internal space through which a gas inflowed through the gas inlet flows.

The ceramic insulator connecting the first electrical heating plate and the second electrical heating plate may have a cylindrical shape.

An exhaust gas reduction device according to an embodiment may include the particulate filter according to any one of the preceding embodiments.

The exhaust gas reduction device including the electrically heated catalyst-coated particulate filter according to the embodiments of the present invention can rapidly reduce HC and NOx discharged during a cold start of a vehicle by having a structure in which an electrical heater and a catalyst coated filter are combined.

Advantageous Effects

The exhaust gas reduction device including the electrically heated catalyst-coated particulate filter according to the embodiments of the present invention can provide an exhaust gas reduction device having a simplified and miniaturized structure and improved durability performance.

However, the effects that can be achieved by the exhaust gas reduction device including the electrically heated catalyst-coated particulate filter according to the embodiments are not limited to those mentioned above, and other effects that are not mentioned will be clearly understood by those skilled in the art from the description below.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a conventional exhaust gas reduction device.

FIG. 2 is a schematic diagram of an exhaust gas reduction device according to an embodiment.

FIG. 3 is a schematic cross-sectional view of a filter unit structure used in the exhaust gas reduction device according to an embodiment

FIG. 4 is a schematic cross-sectional view of a coupling structure of the exhaust gas reduction device according to an embodiment.

FIG. 5 is a schematic diagram of an electrical heating plate according to an embodiment.

FIG. 6 is a schematic cross-sectional view of a coupling structure of an exhaust gas reduction device according to an embodiment.

MODE FOR INVENTION

The present invention may have various modifications and various examples, and therefore specific embodiments are illustrated in the drawing and described in detail through the detailed description. However, this is not intended to limit the present invention to a specific embodiment, and the present invention should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

When describing the present invention, when it is determined that a detailed description of related known technology may unnecessarily obscure the gist of the present invention, the detailed description is omitted. In addition, numbers (e.g., first, second, and the like) used in the description of this specification are merely identifiers to distinguish one component from another.

Further, in the specification, when a component is referred to as being “connected” or “contact” with another component, it should be understood that the component may be directly connected to or directly contact the other component, but unless there is a specific description to the contrary, it should be understood that the component may also be connected or contact via another component in between.

In addition, a component expressed as “portion” in the specification may be a combination of two or more components into one component, or a single component may be divided into two or more components based on a more detailed function. In addition, each component described below may additionally perform some or all of the functions performed by other components in addition to its own main function, and it goes without saying that some of the main functions performed by each component may be performed exclusively by other components.

Hereinafter, exemplary embodiments according to the technical idea of the present invention will be sequentially described in detail.

FIG. 2 is a schematic diagram of an exhaust gas reduction device according to an embodiment. FIG. 3 is a schematic cross-sectional view of a filter unit structure used in the exhaust gas reduction device according to an embodiment. FIG. 4 is a schematic cross-sectional view of a coupling structure of the exhaust gas reduction device according to an embodiment. FIG. 5 is a schematic diagram of an electrical heating plate according to an embodiment. FIG. 6 is a schematic cross-sectional view of a coupling structure of an exhaust gas reduction device according to an embodiment.

An exhaust gas reduction device 100 according to an embodiment includes a catalyst-coated particulate filter 101, and the electrically heatable catalyst-coated particulate filter 101 is formed of plurality of filter unit structures 102 that are stacked and connected, each filter unit structure 102 may include a ceramic insulator 110, an upper filter plate 120, a lower filter plate 130, an upper electrical heating plate 140, a lower electrically heating plate 150, and an upper ceramic insulator 160. In this case, the ceramic insulator 110, the upper filter plate 120, the lower filter plate 130, the upper electrical heating plate 140, and the lower electrically heating plate 150 form a ceramic filter structure for filtering particulate material.

The ceramic insulator 110 may include an exhaust gas passing space 111 through which an exhaust gas passes and is discharged to the outside. The ceramic insulator 110 is a “U” shaped member formed of a first support 115, a second support 116, and a third support 117, and a central region 112 surrounded by the first support 115, the second support 116, and the third support 117, and an open region 113 facing the second support 116 may form the exhaust gas passing space 111.

Upper and lower surfaces of the first support 115, the second support 116, and the third support 117 may be flat. Holes through which bolts penetrate and engage may be formed on the upper and lower surfaces of the first support 115 and the third support 117, and may be used for connection with an upper ceramic insulator 160, which will be described later.

The ceramic insulator 110 performs an electrical insulation function to prevent the upper electrical heating plate 140 and the lower electrically heating plate 150 from electrically shorting each other.

The upper filter plate 120 and the lower filter plate 130 are ceramic or metal fiber filter plates that perform the function of filtering smoke particles. The upper filter plate 120 and the lower filter plate 130 may be made of an oxidized aluminum material.

The upper filter plate 120 is disposed on the ceramic insulator 110 and formed of a porous material, and is coated with a catalyst to purify an exhaust gas. Specifically, the upper filter plate 120 may be disposed such that an edge of the upper filter plate 120 overlaps the upper surfaces of the first support 115, the second support 116, and the third support 117. Bolt holes formed on the upper surfaces of the first support 115, the second support 116, and the third support 117 may be disposed outside the edge of the upper filter plate 120.

The lower filter plate 130 is disposed below the ceramic insulator 110 and made of porous material, and is coated with a catalyst to purify an exhaust gas. Specifically, the lower filter plate 130 may be disposed such that the edge of the lower filter plate 130 overlaps the lower surfaces of the first support 115, the second support 116, and the third support 117. Bolt holes formed on the lower surfaces of the first support 115, the second support 116, and the third support 117 may be disposed outside the edge of the lower filter plate 130.

A lower surface region of each of the first support 115, the second support 116, and the third support 117, where the lower filter plate 130 and the lower electrically heating plate 150 contact, may be formed concavely by providing a step equal to the sum of the thicknesses of the lower filter plate 130 and the lower electrically heating plate 150, and the lower filter plate 130 and the lower electrically heating plate 150 may be accommodated in the concave region such that the lower surfaces of the first support 115, the second support 116, and the third support 117 and the lower electrically heating plate 150 form the same plane.

The upper electrical heating plate 140 is disposed above the upper filter plate 120, and a plurality of penetration holes 141 through which the exhaust gas passes are formed, and may generate heat when a current is supplied. The upper electrical heating plate 140 may be a Fe—Cr—Al alloy material and may be a very thin plate with a thickness of 0.1 mm.

The penetration holes 141 of the upper electrical heating plate 140 may be formed with a diameter of 0.1 mm or less. Since the penetration holes 141 are micro holes, they may be uniformly formed by an etching method rather than a drilling method. The size, number, and distribution of the penetration holes 141 may be adjusted through the etching method.

By adjusting the size, number, and distribution of the penetration holes 141, the electrical resistance distribution of the upper electrical heating plate 140 may be controlled, thereby inducing uniform heat generation. For example, the penetration holes 141 of the upper electrical heating plate 140 are arranged more in a central region than in an outer region, and thus the total area of the penetration holes 141 is large in the central region and decreases toward the outer region of the upper electrical heating plate 140, thereby inducing uniform heat generation of the upper electrical heating plate 140. The penetration holes 141 may have a circular, quadrangle, or other shapes.

The upper electrical heating plate 140 may have a symmetrical shape on both sides such that the current is evenly distributed and the electric heating is uniform. The electrical resistance of the upper electrical heating plate 140 may be less than the electrical resistance of the upper filter plate 120 such that the current does not flow through the upper filter plate 120.

The upper electrical heating plate 140 may include a first upper electrical heating plate connection plate 144 and a second upper electrical heating plate connection plate 146.

The first upper electrical heating plate connection plate 144 is a member that protrudes downward from a first end 143 of the upper electrical heating plate 140 to allow the upper electrical heating plate 140 to be connected and fixed to the second support 116 of the ceramic insulator 110. The first upper electrical heating plate connection plate 144 may be connected and fixed to a side surface of the second support 116 and may be fixed with a bolt.

The upper filter plate 120 may be fixed to the ceramic insulator 110 by the upper electrical heating plate 140. Additionally, the upper filter plate 120 and the upper electrical heating plate 140 may be connected using a ceramic bonding, which improves the heat transfer effect and enhances the exhaust gas purification efficiency under cold start conditions.

The second upper electrical heating plate connection plate 146 is a member that protrudes upward from the second end 145 facing the first end 143 of the upper electrical heating plate 140, and may be connected and fixed to the side surface of the second upper support 166 of the upper ceramic insulator 160, which will be described later.

The lower electrically heating plate 150 is disposed below the lower filter plate 130, and a plurality of penetration holes 151 through which an exhaust gas passes are formed, and may generate heat when current is supplied. The lower electrically heating plate 150 may be a Fe—Cr—Al alloy material and may be a very thin plate with a thickness of 0.1 mm.

The penetration hole 151 of the lower electrically heating plate 150 may be formed with a diameter of 0.1 mm or less. Since the penetration holes 151 are micro holes, they may be uniformly formed by an etching method rather than a drilling method. The size, number, and distribution of the penetration holes 151 may be adjusted through the etching method.

By adjusting the size, number, and distribution of the penetration holes 151, the electrical resistance distribution of the lower electrical heating plate 150 may be controlled, thereby inducing uniform heat generation. For example, the penetration holes 151 of the lower electrical heating plate 150 are arranged more in a central region than in an outer region, and thus the total area of the penetration holes 151 is large in the central region and decreases toward the outer region of the lower electrical heating plate 150, thereby inducing uniform heat generation of the lower electrical heating plate 150. The penetration holes 151 may have a circular, quadrangle, or other shapes.

The lower electrical heating plate 150 may have a symmetrical shape on both sides such that the current is evenly distributed and the electric heating is uniform. The electrical resistance of the lower electrical heating plate 150 may be less than the electrical resistance of the upper filter plate 130 such that the current does not flow through the upper filter plate 130.

The lower electrically heating plate 150 may include a first lower electrically heating plate connection plate 154 and a second lower electrically heating plate connection plate 156.

The first lower electrically heating plate connection plate 154 is a member that protrudes upward from the first end 153 of the lower electrically heating plate 150 to allow the lower electrically heating plate 150 to be connected and fixed to the second support 116 of the ceramic insulator 110. The first lower electrically heating plate connection plate 154 may be connected and fixed to the side surface of the second support 116 and fixed with a bolt.

The lower filter plate 130 may be fixed to the ceramic insulator 110 by the lower electrically heating plate 150. Additionally, the lower filter plate 130 and the lower electrically heating plate 150 may be connected by ceramic bonding, which improves the heat transfer effect and enhances the exhaust gas purification efficiency under cold start conditions.

An upper catalyst plate for purifying gas may be additionally disposed between the upper filter plate 120 and the upper electrical heating plate 140, and a lower catalyst plate for purifying gas may be additionally disposed between the lower filter plate 130 and the lower electrically heating plate 150. The electrical resistance of the upper electrical heating plate 140 may be less than the electrical resistance of the upper catalyst plate, and the electrical resistance of the lower electrically heating plate 150 may be less than the electrical resistance of the lower catalyst plate.

The upper ceramic insulator 160 is disposed above the upper electrical heating plate 140 and may include an upper exhaust gas passing space 161.

The upper ceramic insulator 160 is a “U” shaped member formed of a first upper support 165, a second upper support 166, and a third upper support 167, and an upper central region 162 surrounded by the first upper support 165, the second upper support 166, and the third upper support 167, and an upper open region 163 facing the second upper support 166 may form an upper exhaust gas passing space 161.

Upper and lower surfaces of the first upper support 165, the second upper support 166, and the third upper support 167 may be flat. Holes through which bolts penetrate and engage may be formed on the upper and lower surfaces of the first upper support 165 and the third upper support 167.

Lower surface regions of the first upper support 165, the second upper support 166, and the third upper support 167, where the upper filter plate 120 and the upper electrical heating plate 140 contact, may be formed concavely by providing a step equal to the sum of the thicknesses of the upper filter plate 120 and the upper electrical heating plate 140, and the upper filter plate 120 and the upper electrical heating plate 140 may be accommodated in the concave region such that the lower surfaces of the first upper support 165, the second upper support 166, and the third upper support 167 and the lower surface of the upper filter plate 120 form the same plane.

The first upper support 165 is fixed by contacting the third support 117, the third upper support 167 is fixed by contacting the first support 115, the second upper support 166 is disposed on the open region 113, and the upper open region 163 may be disposed on the second support 116. That is, the ceramic insulator 110 and the upper ceramic insulator 160 may be connected such that the upper open region 163 and the open region 113 are disposed in opposite directions. The ceramic insulator 110 and the upper ceramic insulator 160 may be connected and fixed by various known connection methods such as a bolt and the like.

The upper ceramic insulator 160 is combined with the ceramic insulator 110 and performs a function of fixing the upper filter plate 120 and the upper electrical heating plate 140 therebetween. In addition, as described later, it performs a function of being connected to a lower electrically heating plate and a ceramic insulator of another filter unit structure.

The second upper electrical heating plate connection plate 146 of the upper electrical heating plate 140 may be connected and fixed to the side surface of the second upper support 166, and the second lower electrically heating plate connection plate 156 of the lower electrically heating plate 150 may be connected and fixed to a side surface of a second upper support of a upper ceramic insulator of another filter unit structure disposed below the filter unit structure 102. A bolt connection method may be used as a fixing method.

The second lower electrically heating plate connection plate 156 of the lower electrically heating plate 150 is a member protruding downward from a second end 155 facing the first end 153 of the lower electrically heating plate 150 and may be connected to a side surface of a second upper support of an upper ceramic insulator of another filter unit structure disposed below the filter unit structure 102.

In this way, stacked connection of filter unit structures can be easily achieved. That is, an upper surface of an upper ceramic insulator of another filter unit structure is connected and fixed to the lower surface of the ceramic insulator 110 of the filter unit structure 102, and the second lower electrically heating plate connection plate 156 is connected and fixed to a side surface of a second upper support of an upper ceramic insulator of another filter unit structure. A bolt connection method may be used as a fixing method.

A plurality of filter unit structures 102 are laminated and connected to form the electrically heated catalyst-coated particulate filter 101, and the appearance of the electrically heated catalyst-coated particulate filter 101 is canned, and power may be connected to the upper electrical heating plate 140 and the lower electrically heating plate 150 to form the exhaust gas reduction device 100.

The exhaust gas may be discharged through the exhaust gas passing space 111 by passing through the penetration holes 141 of the upper electrical heating plate 140 and the upper filter plate 120, and through the penetration holes 151 of the lower electrically heating plate 150 and the lower filter plate 130 by passing through the exhaust gas passing space 111.

Here, the upper electrical heating plate 140 and the upper filter plate 120 are fixed to the ceramic insulator 110 in a state of contact, and the lower electrically heating plate 150 and the lower filter plate 130 are fixed to the ceramic insulator 110 in a state of contact. Therefore, the smoke accumulated on the upper filter plate 120 and the lower filter plate 130 may be burned off periodically or when necessary, and gaseous materials, such as unburned hydrocarbon, CO, and NOx, may be purified by catalytic reaction while passing through the upper filter plate 120 and the lower filter plate 130, which are coated with a catalyst.

When an exhaust gas temperature is low, such as at the beginning of a start-up, the heat generated from the upper electrical heating plate 140 and the lower electrically heating plate 150 may be used to rapidly increase the exhaust gas temperature, thereby increasing temperatures of the upper filter plate 120 and the lower filter plate 130 to actively promote the catalytic reaction, thereby improving the gas-phase exhaust gas purification characteristics.

In addition, the exhaust gas reduction device 100 may be significantly reduced in size by combining an electrical heater and a catalyst-coated filter. In addition, the exhaust gas reduction device 100 is a structure in which the plurality of filter unit structures 102 are connected in layers, and therefore it is easier to manufacture and has superior durability compared to a conventional device.

An exhaust gas reduction device 200 according to an embodiment includes an electrically heated catalyst-coated particulate filter 203, wherein the electrically heated catalyst-coated particulate filter 203 is formed by stacking and connecting a plurality of filter unit structures 202, wherein the filter unit structure 202 may include a ceramic filter structure configured to filter a particulate material, a first electrical heating plate 220, and a second electrical heating plate 230, and the ceramic filter structure may include a ceramic filter plate 210.

The ceramic filter plate 210 may include a gas inlet 211 for inflowing an exhaust gas into an internal space of the ceramic filter plate 210. The gas inlet 211 may be formed at one end of the ceramic filter plate 210, and the exhaust gas may move toward the internal space of the ceramic filter plate 210 through the gas inlet 211.

The ceramic filter plate 210 performs an electrical insulation function to prevent the first electrical heating plate 220 and the second electrical heating plate 230 from being electrically shorted to each other, and performs a function of filtering smoke particles using a filter plate made of ceramic. The ceramic filter plate 210 may also be formed of a porous material and may be coated with a catalyst to purify the exhaust gas.

The ceramic filter plate 210 may be formed by extruding a ceramic material for filtering smoke particles, and may be formed by any other method.

A first electrical heating plate 220 may be disposed on the upper side of the ceramic filter plate 210, and a second electrical heating plate 230 may be disposed on the lower side of the ceramic filter plate 210.

The first electrical heating plate 220 hasa plurality of penetration holes through which exhaust gas passes, and heat may be generated when a current is supplied. The first electrical heating plate 220 may be a Fe—Cr—Al alloy material and may be a very thin plate with a thickness of 0.1 mm.

The penetration holes of the first electrical heating plate 220 may be formed with a diameter of 0.1 mm or less. Since the penetration holes are microscopic holes, they may be uniformly formed by an etching method rather than a drilling method. The size, number, and distribution of the penetration holes may be adjusted through the etching method.

By adjusting the size, number, and distribution of the penetration holes 151, the electrical resistance distribution of the first electrical heating plate 220 may be controlled, thereby inducing uniform heat generation. For example, the penetration holes of the first electrical heating plate 220 are arranged more in a central region than in an outer region, and thus the total area of the penetration holes is large in the central region and decreases toward the outer region of the first electrical heating plate 220, thereby inducing uniform heat generation of the first electrical heating plate 220. The penetration holes may have a circular, quadrangle, or other shapes.

The first electrical heating plate 220 may have a symmetrical shape on both sides such that the current is evenly distributed and the electric heating is uniform.

The first electrical heating plate 220 may be designed in parallel to solve the drawback of large capacity current flowing through the entire electrical heating plate when the electrical heating plate is coupled in series. In a parallel design, a current may flow from one end to the other, and then from the other end to the first end.

The second electrical heating plate 230 is disposed below the ceramic filter plate 210, and a plurality of penetration holes through which exhaust gas passes are formed, and may generate heat when current is supplied. The second electrical heating plate 230 may be a Fe—Cr—Al alloy material and may be a very thin plate with a thickness of 0.1 mm.

The penetration holes of the second electrical heating plate 230 may be formed with a diameter of 0.1 mm or less. Since penetration holes are microscopic holes, they can be uniformly formed by the etching method rather than the drilling method. The size, number, and distribution of the penetration holes may be adjusted through the etching method.

By adjusting the size, number, and distribution of the penetration holes, the electrical resistance distribution of the second electrical heating plate 230 may be controlled, thereby inducing uniform heat generation. For example, the penetration holes of the second electrical heating plate 230 are arranged more in a central region than in an outer region, and thus the total area of the penetration holes is large in the central region and decreases toward the outer region of the second electrical heating plate 230, thereby inducing uniform heat generation of the second electrical heating plate 230. The penetration holes may have a circular, quadrangle, or other shapes.

The second electrical heating plate 230 may have a symmetrical shape on both sides such that the current is evenly distributed and the electric heating is uniform.

The second electrical heating plate 230 may be designed in parallel to solve the drawback of large capacity current flowing through the entire electrical heating plate when the electrical heating plate is coupled in series. In a parallel design, a current may flow from one end to the other, and then from the other end to the first end.

Holes through which bolts or the like may penetrate and engage may be formed on upper and lower surfaces of edges of the ceramic filter plate 210, the first electrical heating plate 220, and the second electrical heating plate 230. The filter unit structures 202 may be connected and fixed by various known connection methods, such as a bolt and the like.

In the filter unit structure 202 used in the exhaust gas reduction device 200, the filter unit structure 202 may further include a second ceramic filter plate 240 disposed above the first electrical heating plate 220.

The second ceramic filter plate 240 is fixed to the ceramic filter plate 210 with the first electrical heating plate 220 in between, and a gas outlet 241 that may discharge an exhaust gas inside the second ceramic filter plate 240 to the outside may be formed at one end of the second ceramic filter plate 240.

The second ceramic filter plate 240 is a filter plate made of ceramic and performs the function of filtering smoke particles. The second ceramic filter plate 240 may also be formed of a porous material and may be coated with a catalyst to purify exhaust gas.

The second ceramic filter plate 240 may be formed by extruding a filter plate and a ceramic material for filtering smoke particles, and may be formed by any other method.

The gas outlet 241 of the second ceramic filter plate 240 is disposed on the opposite side of the gas inlet 211 of the ceramic filter plate 210 such that the exhaust gas that enters into the ceramic filter plate 210 through the gas inlet 211 passes through the plurality of penetration holes of the first electrical heating plate 220 and moves to the second ceramic filter plate 240, and then flows out to the outside through the gas outlet 241 in the opposite direction of the inflow direction.

A third ceramic filter plate (not shown) may also be disposed at a bottom of the second electrical heating plate 230 of the filter unit structure 202 used in the exhaust gas reduction device 200.

The third ceramic filter plate is the same filter plate as the ceramic filter plate 210 and the second ceramic filter plate 240. The third ceramic filter plate may include a gas outlet (not shown) through which an exhaust gas, which has inflowed into the ceramic filter plate 210 through the gas inlet 211 of the ceramic filter plate 210 and then moved to the third ceramic filter plate through the second electrical heating plate 230, can be discharged to the outside. A gas outlet of the third ceramic filter plate is formed in the opposite direction of the gas inlet 211 of the ceramic filter plate 210.

Due to such a stacking method, the connected filter unit structures 202 may be overlapped in opposite directions to form an electrically heated catalyst-coated particulate filter 230.

The appearance of the electrically heated catalyst-coated particulate filter 230 may be scanned, and power may be connected to the first electrical heating plate 220 and the second electrical heating plate 230 to form the exhaust gas reduction device 200.

Since the first electrical heating plate 220 and the second electrical heating plate 230 are fixed in contact with the ceramic filter plate 210, the smoke accumulated on the ceramic filter plate 210 may be burned off periodically or when necessary, and the gaseous materials, such as unburned hydrocarbon, CO, and NOx, may be purified through catalytic reaction as they pass through the ceramic filter plate 210 coated with a catalyst.

When an exhaust gas temperature is low, such as at the beginning of a start-up, the heat generated from the first electrical heating plate 220 and the second electrical heating plate 230 may be used to rapidly increase an exhaust gas temperature, thereby increasing a temperature of the ceramic filter plate 210 to actively promote the catalytic reaction, thereby improving the gas-phase exhaust gas purification characteristics.

In addition, the exhaust gas reduction device 200 can be significantly reduced in size by combining an electrical heater and a catalyst-coated filter. In addition, the exhaust gas reduction device 200 is a structure in which a plurality of filter unit structures 202 are connected in layers, and thus it is easier to manufacture and has superior durability compared to the conventional device.

A particulate filter used in the exhaust gas reduction device according to an embodiment may include a first filter unit structure and a second filter unit structure, and the first filter unit structure and the second filter unit structure may be characterized in that they are stacked in a manner that they are connected to each other.

At least one of the first filter unit structure or the second filter unit structure included in the particulate filter may be formed of a filter unit structure according to an embodiment.

A filter unit structure included in the particulate filter may include a ceramic filter structure, a first electrical heating plate disposed on one side of the ceramic filter structure and formed to generate heat, and a second electrical heating plate disposed on the other side of the ceramic filter structure and formed to generate heat, and a gas flow path through which an exhaust gas flows may be formed at one end of the ceramic filter structure.

The first filter unit structure and the second filter unit structure included in the particulate filter are stacked in opposite directions, and thus a gas flow path of the first filter unit structure may be disposed in the opposite direction of a gas flow path of the second filter unit structure.

The description given above presents the best mode of the present invention, and provides examples to describe the present invention and to enable a person of an ordinary skill in the art to make and use the present invention. The specification written as above does not limit the present invention to the specific terms presented.

Accordingly, although the present invention has been described in detail with reference to the examples described above, a person of an ordinary skill in the art can modify, alter and transform the examples without departing from the scope of the present invention.

Description of Symbols

• • 10: electrical heater
  • 20: three-way catalyst
  • 30: particulate filter
  • 100: exhaust gas reduction device
  • 101: electrically heatable catalyst-coated particulate filter
  • 102: filter unit structure
  • 110: ceramic insulator
  • 111: exhaust gas passing space
  • 112: central region
  • 113: open region
  • 115: first support
  • 116: second support
  • 117: third support
  • 120: upper filter plate
  • 130: lower filter plate
  • 140: upper electrical heating plate
  • 141: penetration hole
  • 143: first end
  • 144: first upper electrical heating plate connection plate
  • 145: second end
  • 146: second upper electrical heating plate connection plate
  • 150: lower electrical heating plate
  • 151: penetration hole
  • 153: first end
  • 154: first lower electrical heating plate connection plate
  • 155: second end
  • 156: second lower electrical heating plate connection plate
  • 160: upper ceramic insulator
  • 161: exhaust gas passing space
  • 162: upper central region
  • 163: upper open region
  • 165: first upper support
  • 166: second upper support
  • 167: third upper support
  • 200: exhaust gas reduction device
  • 201: electrical heating plate
  • 202: filter unit structure
  • 203: electrically heatable catalyst-coated particulate filter
  • 211: gas inlet
  • 210: ceramic filter plate
  • 220: first electrical heating plate
  • 230: second electrical heating plate
  • 240: second ceramic filter plate
  • 241: gas outlet