WO2006137695A1

WO2006137695A1 - Burner for regeneration of diesel particulate filter

Info

Publication number: WO2006137695A1
Application number: PCT/KR2006/002397
Authority: WO
Inventors: Sang Hyun Jeong; Seong Hun Sim; Won Seok Hong
Original assignee: Korea Institute Of Machinery And Materials
Priority date: 2005-06-22
Filing date: 2006-06-21
Publication date: 2006-12-28
Also published as: KR100542803B1; US20100077731A1

Abstract

Provided is a burner for regenerating a diesel engine particulate filter. The burner includes: a combustion chamber for receiving a exhaust gas through connecting pipes from a diesel engine; a carburetor including a gasifying chamber for gasifying a liquid fuel, an atomizer for atomizing and supplying the liquid fuel to the gasifying chamber, and a convey air inflow line for flowing an external air into the gasifying chamber for conveying the gasified fuel into a mixed gas supplying unit; a mixed gas supplying unit for mixing the gasified fuel with an external air for burning, and supplying the mixed gaseous fuel to the combustion chamber; a combustor disposed in the combustion chamber for injecting the mixed gaseous fuel; an igniter for igniting the mixed gaseous fuel injected from the combustor; and a flame sensor for sensing whether the flame is made on the surface of the combustor or not.

Description

BURNER FOR REGENERATION OF DIESEL PARTICULATE

FILTER

Technical Field

[1] The present invention relates to a diesel particulate filter (DPF); and more particularly, to a burner for regenerating a DPF that reduces soot by filtering soot particles included in an exhaust gas outputted from a diesel engine. Background Art

[2] Diesel engines have been generally equipped in trains, vessels, and commercial vehicles. Also, diesel passenger vehicles came out to the market, recently. Thus, the use of diesel engines has increased.

[3] As the use for diesel engines has increased, the large amount of particulate matters

(PM) such as soot and soluble organic fraction (SOF) are produced from the diesel engines. Since such particulate matters (PM) are major factors for environment pollution, especially, air pollution. Therefore, the regulation of diesel engines has become tightened.

[4] In order to resolve the pollution problem of diesel engines, a diesel particulate filter

(DPF) was introduced. The DPF collects soot outputted from a diesel vehicle in order to prevent soot particles from being exhausted into the air. Also, there are many researches in progress for developing the DPF.

[5] FIG. 1 shows a conventional diesel particulate filter for reducing soot produced from a diesel engine, which were introduced in Korea Patent Publication No. 2003-0003599.

[6] Referring to FIG. 1, the conventional diesel particulate filter (DPF) includes a main body 10 having a monolith type ceramic filter 11 for filtering soot particles in an exhaust gas outputted from a diesel engine, and a burner 1 for generating the monolith ceramic filter 11. The burner 1 includes a combustor 4 for injecting mixed fuel supplied from a fuel injection pump 2 and an air pump 3, and an ignition rod 5.

[7] In the conventional DPF, soot particles included in the exhaust gas outputted from the diesel engine are collected by the monolith type ceramic filter 11. When the large amount of soot particles is trapped in the ceramic filter 11, the pressure loss of the ceramic filter 14 significantly increases. It greatly influences the back pressure of a diesel engine. Therefore, the soot particles collected in the filter must be removed regularly from the filter 11 when a predetermined pressure is dropped. Conventionally, the soot particles are removed from the filter 11 by increasing the temperature of exhaust gas to be higher than the oxidation temperature of the soot, for example, higher than 600⁰C, so as to oxidize (burn) the soot particles trapped in the ceramic filter 11. In order to raise the temperature of the exhaust gas to be higher than the oxidation temperature of the soot particles, the flame of the burner 1 is used as a heat supplying device. That is, a pressure sensor 6 may sense that an internal pressure of the ceramic filter 11 increases after the large amount of soot particles such as carbon is trapped in the filter. Then, the pressure sensor 6 informs the controller 7 that the internal pressure increases, and the controller 7 drives the burner 1 to burn the soot particles in the filter 11. Then, the combustor 4 injects the fuel, and the ignition rod 5 ignites the fire on the injected fuel. The combustor 4 raises the internal temperature of the exhaust gas channel 20, while a flame holder 8 sustains the flame made by the combustor 4. Therefore, the soot particles collected at the ceramic filter 11 are burned and eliminated. Then, the ceramic filter 11 can be newly used to collect the soot particles outputted from the diesel engine.

[8] As described above, the conventional liquid fuel injection type burner lengthily forms the flame as shown in FIG. 1. It is difficult to stably sustain the lengthily formed flame although the flame holder 8 is included. Also, the stability of the flame is greatly influenced by driving conditions of the engine. That is, it is very difficult to stably sustain when the amount of following the exhaust gas outputted from the engine and the pressure conditions change abruptly. Thus, the flame uncontrollably shakes in the exhaust gas, and is easily extinguished. These shortcomings make the conventional DPF to become unpractical.

[9] Especially, the amount of flowing the exhaust gas or the pressure abruptly varies when the diesel engine accelerates or decelerates. In this case, it is very difficult to increase or sustain the temperature in the exhaust gas channel 20 because the abrupt variation makes the flame instable and to be extinguished. Accordingly, the regeneration of the filter through oxidizing the soot particles trapped in the filter becomes difficult. That is, the conventional burner may sustain the flame stably when the diesel engine is regularly driven, for example, when the engine is kept ticking over, when the engine is driven at a constant speed, and when the engine stops. However, the conventional burner cannot sustain the flame stably or often extinguishes the flame when the driving conditions of the diesel engine abruptly change, for example, when the diesel engine accelerates or decelerates. In this case, the conventional burner cannot smoothly burn the soot particles trapped in the filter 11. Therefore, the state of the diesel particulate filter is getting deteriorated. Finally, the filter 11 becomes incapable of filtering diesel particulate. Disclosure of Invention Technical Problem [10] It is, therefore, an object of the present invention to provide a burner for generating a diesel particulate filter, which is enhanced to constantly sustain a stable flame in the flow of exhaust gas without being influenced by the abrupt variation of driving conditions of the diesel engine, and a diesel particulate filter having the same. Technical Solution

[11] In accordance with one aspect of the present invention, there is a burner for regenerating a diesel engine particulate filter including: a combustion chamber for receiving a exhaust gas from a diesel engine through at least one of connecting pipes connected to an exhaust gas channel of the diesel engine; a carburetor for gasifying liquid fuel supplied from a fuel tank by a fuel pump; a mixed gas supplying unit for mixing the gasified fuel from the gasifying chamber with an external air for burning, and supplying the mixed gaseous fuel to the combustion chamber; a combustor made of porous material and disposed in the combustion chamber for injecting the mixed gaseous fuel supplied from the mixed supplying unit; an igniter for igniting the mixed gaseous fuel injected from the combustor; and a flame sensor for sensing whether the flame is made on the surface of the combustor or not.

[12] The carburetor may includes a gasifying chamber for gasifying a liquid fuel, an atomizer for atomizing the liquid fuel into fine liquid drops and supplying the atomized liquid fuel to the gasifying chamber, and a convey air inflow line for forming a channel to flow an external air into the gasifying chamber for conveying the gasified fuel into a mixed gas supplying unit.

[13] The mixed gas supplying unit may include: a mixing chamber for forming a mixed gas by mixing an external air for burning and a gasified fuel; a burning air inflow line communicated with the mixing chamber for forming a channel for flowing an external air for burning into the mixing chamber; a fuel inflow line communicated with the mixing chamber and the gasifying chamber for forming a channel for flowing a gasified fuel into the mixing chamber; and a mixed gas inflow line communicated with the mixing chamber and the combustion chamber for forming a channel for flowing the mixed gas from the mixing chamber into the combustion chamber.

[14] The porous material of the combustor may be one selected from the group consisting of mat type metal fiber, ceramic and foam metal, and the combustor may have one of a cylinder shape, a cone shape, and a rectangle pipe shape.

[15] The burner may further include an electric control unit for electrically feedback- controlling: a temperature and a pressure of at least one spot in the combustion chamber; an amount of flowing external air for conveying into the gasifying chamber, a temperature and pressure inside the gasifying chamber; a temperature, a pressure, and an amount of flowing an external air for burning into the mixed gas supplying unit; an amount of flowing a liquid fuel supplied from the fuel pump; a temperature and a pressure of an exhaust gas after passing through a diesel particulate filter; and operations of the combustor, the igniter, the flame sensor and the fuel pump.

Advantageous Effects

[16] A burner for regenerating a diesel particulate filter according to the present invention has following advantages.

[17] At first, the burner according to the present invention can instantly ignite and extinguish flames on a combustor because the burner includes the combustor that is made of porous material having a plurality of flame holes. Also, the burner can stably sustain the flames although the amount of flowing an exhaust gas and the pressure of the exhaust gas abruptly changes due to the abrupt variation of the load of the diesel engine.

[18] Secondly, since the burner according to the present invention includes the combustor having a comparatively larger surface by forming the combustor made of porous material in a cone shape, a cylinder shape, and a rectangle pipe shape, the heat can be exchanged quickly from the flame to the exhaust gas, and the combustion chamber can sustain a uniform temperature.

[19] Thirdly, the inside wall of the combustion chamber is lined with heat resistant material such as ceramic and firebrick to insulate and to accumulate heat at the same time, and the insulating material can be sustained to be clean because the soot particles on the insulating material are oxidized by the accumulated heat.

[20] Finally, the burner according to the present invention can be used to regenerate a particulate filter in diesel engines in trains, vessels and vehicles. The applicability of the burner according to the present invention is very wide as other purposes of the burner. It is very valuable in a view of the environmental population. Brief Description of the Drawings

[21] The above and other objects and features of the present invention will become apparent from the following description of the preferred embodiments given in conjunction with the accompanying drawings, in which:

[22] FIG. 1 is a diagram illustrating a conventional diesel particulate filter;

[23] FIG. 2 is a diagram illustrating a diesel particulate filter having a burner for regenerating the diesel particulate filter according to an embodiment of the present invention;

[24] FIG. 3 is a diagram illustrating the burner for regenerating the diesel particulate filter shown in FIG. 2 according to an embodiment of the present invention;

[25] FIG. 4 is a diagram for describing heat-exchange between a convey air inflow line and an exhaust gas channel or between a burning air inflow line and an exhaust gas channel shown in FIG. 2;

[26] FIGs. 5 and 6 are perspective views of a combustor according to another embodiment of the present invention;

[27] FIG. 7 is a diagram illustrating a combustion chamber with a connecting pipe according to an embodiment of the present invention;

[28] FIG. 8 shows the front view of the combustion chamber shown in FIG. 7 in an X direction;

[29] FIG. 9 is a diagram illustrating a combustion chamber with a connecting pipe according to another embodiment of the present invention;

[30] FIG. 10 shows the front view of the combustion chamber shown in FIG. 9 in a Y direction;

[31] FIG. 11 is a perspective view illustrating a flame holder, an exhaust gas s wirier and a guiding plate shown in FIG. 7 and FIG. 8;

[32] FIG. 12 is a perspective view illustrating a flame holder, an exhaust gas s wirier and a guiding plate shown in FIG. 9 and FIG. 10;

[33] FIG. 13 and FIG. 14 show a connecting pipe disposed to be separated from the center of the cross-section of a combustion chamber;

[34] FIG. 15 is a perspective view illustrating a supplementary air inflow line and a supplementary air swirler shown in FIG. 13 and FIG. 14; and

[35] FIG. 16 is a diagram illustrating the burner for regenerating a diesel particulate filter that is feed-back controlled by an electric control unit according to an embodiment of the present invention. Best Mode for Carrying Out the Invention

[36] Other objects and aspects of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, which is set forth hereinafter.

[37] FIG. 2 is a diagram illustrating a diesel particulate filter having a burner for regenerating the diesel particulate filter according to an embodiment of the present invention, and FIG. 3 is a diagram illustrating a burner for regenerating the diesel particulate filter shown in FIG. 2 according to an embodiment of the present invention.

[38] Referring to FIG. 2, the burner 100 according to the present embodiment includes one side connected to an exhaust gas channel 300 through a connecting pipe 200 and other side connected to a particulate filtering unit 400 having a filter 410 for collecting soot particles.

[39] As shown in FIG. 3, the burner 100 includes a combustion chamber 110 for receiving an exhaust gas from an engine, a carburetorl20 for gasifying a liquid fuel such as diesel, a mixed gas supplying unit 130 for mixing the gasified fuel with an external air and supplying the mixed gas to the combustion chamber 110, a combustor 140 disposed inside the combustion chamber 110 for injecting the mixed gas supplied from the mixed gas supplying unit 130, an igniter 150 for forming a flame by igniting the mixed gas injected from the combustor 140, and a flame sensor 160 for sensing whether a flame is made on the combustor 140 or not.

[40] The combustion chamber 110 is connected to at least one of connecting pipes 200 that are connected to the exhaust gas channel 300, and the exhaust gas flows into the combustion chamber 110 through the connecting pipe 200. The inner wall of the combustion chamber 110 is lined with a thermal insulator 111 such as ceramic wool, creak wool, or fire brick. The thermal insulator 111 insulates the inner wall of the combustion chamber 110 so as to accumulate heat inside the combustion chamber 110. Since soot particles attached on the thermal insulator 111 are oxidized by the accumulated heat, the thermal insulator 111 is sustained as a clean state.

[41] The carburetor 120 includes a gasifying chamber 123 for gasifying a liquid fuel which is supplied from a fuel tank 122 by a fuel pump 121, and a convey air inflow line 124 for forming a passage 124a for flowing an external air into the gasifying chamber 123. Also, the carburetor 120 further includes a gasifying unit for supplying heat to gasify the liquid fuel into a gaseous state in the gasifying chamber 123. Various devices for gasifying a liquid fuel may be used as the gasifying unit. For example, a heater that gasifies the liquid fuel through heating may be used as the gasifying unit. The external air from the convey air inflow line 124 conveys the gasified fuel to the mixed gas supplying unit 130 in order to mix the gaseous liquid with an air for burning. FIG. 3 exemplary shows that normal temperature air flows through the convey air inflow line 124. However, an external air may be pre-heated while passing through the convey air inflow line 124 as shown in FIG. 4. That is, the convey air inflow line 124 has a predetermined portion disposed to pass the exhaust gas channel 300 so as to heat the external air while passing the convey air inflow line 124 through heat-exchanging with the exhaust gas outputted from the diesel engine. Therefore, the pre-heated external air may inflow into the gasifying chamber 123. Referring to FIG. 3 again, the carburetor 120 may include an atomizer 126 for atomizing the liquid fuel into fine liquid drops in order to accelerate gasifying in the gasifying chamber 123. For example, the atomizer 126 may be an ultrasonic atomizer.

[42] The mixed gas supplying unit 130 includes a mixing chamber 131 for forming the mixed gas by mixing an external air with the gasified fuel, a burning air inflow line 132 communicated with the mixing chamber 131 for forming a passage 132a for flowing an air into the mixing chamber 131, a fuel inflow line 133 communicated with the mixing chamber 131 and the gasifying chamber 123 of the carburetor 120 for forming a passage 133a to flow the mixed gas into the mixing chamber 131, and a mixed gas inflow line 134 communicated with the mixing chamber 131 and the combustion chamber 110 for forming a passage 134a to flow the mixed gas into the combustion chamber 110. The external air inflow passage 132a formed in the external air inflow line 132 and the mixing chamber 131 may be formed in a ventury shape having a cross-section that is gradually reduced along the flow of the external air. By forming the external air inflow line 132 and the mixing chamber 131 in the ventury shape, the mixing chamber 131 has a comparatively lower pressure than the gasifying chamber 123. Due to the pressure difference between the mixing chamber 131 and the gasifying chamber 123, the gasified fuel in the gasifying chamber 123 smoothly moves to the mixing chamber 131. Therefore, the mixed gas made of the fuel and the air is smoothly supplied from the gasifying chamber 123 to the combustion chamber 110. Herein, FIG. 3 exemplary shows that a normal temperature external air inflows through the burning air inflow line 132. However, an external air may be pre-heated while passing through the burning air inflow line 132 as shown in FIG. 4. That is, the burning air inflow line 132 may include a predetermined portion disposed to pass inside the exhaust gas channel 300 so as to heat the air while flowing along the burning air inflow line 132 through heat-exchanging with the exhaust gas outputted from the diesel engine. As a result, the pre-heated air may flow into the mixing chamber 131 as shown in FIG. 4.

[43] The combustor 140, as shown in FIG. 3, may be formed of high heat resistant mat shaped metal fibers. Also, the combustor 140 may be formed of porous material having high heat resistance characteristics such as porous ceramic or foam-metal. As described above, since the combustor 140 is formed of porous material that functions as a plurality of fine flame holes, the combustor 140 forms a plurality of very short flames at allatonceness. Accordingly, the combustor 130 can hold accumulated heat on the surface thereof, and the accumulated heat on the surface prevents the flames from being extinguished, and makes flames to be ignited on all over the surface thereof in a very short time. Although FIG. 3 shows a con shaped porous combustor 140, the combustor may have a shape of a cylinder or a rectangular pipe as like as the combustors 140a and 140b shown in FIG. 5 and FIG. 6. As shown in FIG. 3, the combustor 140 may further include a porous supporting member 141 coupled to the inner side of the porous material. Such a porous supporting member 141 functions to hold the shape of combustor 140.

[44] The igniter 150 ignites the mixed gas injected from the combustor 140. That is, the igniter 150 receives a high voltage from a power supply 153 and generates the electric discharging using the received high voltage to ignite the mixed gas injected from the combustor 140. As a result, the flames are made on the combustor 140. As described above, since the igniter 150 ignites the mixed gas from the combustor 140, the ignite performance of the igniter 150 may be degraded by soot particles attached on the combustor 140. Therefore, the igniting member 151 of the igniter 150 must be sustained as clean. In order to sustain the igniting member 151 clean, a clean air supplying line 152 may be further included to supply clean external air to the igniting member 151.

[45] The flame sensor 160 senses whether flames are formed on the surface of the combustor 140 or not. If the flame sensor 160 senses that flames are made on the surface of combustor 140, the flame sensor 160 stops the igniter 150. Therefore, the flame sensing member 161 of the frame sensor 160 must be sustained clean. In order to sustain the frame sensor 160 clean, a clean air supplying line 162 may be further included for supplying fresh air as like as the igniter member 151 of the igniter 150.

[46] FIGs. 7 through 10 show connecting pipes for connecting an exhaust gas channel and a combustion chamber in order to flow an exhaust gas from a diesel engine to a combustion chamber according to various embodiment of the present invention.

[47] As shown, the burner 100 according to the present embodiment may include a single connecting pipe 200 or a plurality of connecting pipes 200a and 200b branched from the exhaust gas channel. Such a connecting pipe 200, 200a or 200b is connected to the combustion chamber 110. As shown in FIGs. 7 and 8, the connecting pipe 200a may be connected to the side wall of the combustion chamber 110. As an alternative plan, the connecting pipe 200b may be connected to the front surface of the combustion chamber 110 as shown in FIG. 9 and FIG. 10.

[48] If the connecting pipe 200a or 200b is connected to the side wall or the front of the combustion chamber 110, a porous flame holder 112 may be disposed to surround the external circumference of the combustor 140 as shown in FIG. 11 and FIG. 12. Such a flame holder 112 holds the flames. Also, an exhaust gas swirler 113 may be disposed between the inner wall of the flame holder 112 and the surface of the combustor 140. Such an exhaust gas swirler 113 swirls the exhaust gas while flowing the exhaust gas into the combustion chamber 140 so as to uniformly distribute the exhaust gas around the combustor 140. Furthermore, a guiding plate 114 may be vertically disposed at one end of the flame holder 112. The guiding plate 114 forms a passage to guide the exhaust gas to pass to the exhaust gas swirler 113. Therefore, it can resolve the flame instability problem that is generated by the exhaust gas directly concentrated at the surface of the combustor 140. Also, the swirler accelerates heat-exchange between the flames and the exhaust gas so as to effectively increase the temperature of the exhaust gas.

[49] As shown in FIG. 13 and FIG. 14, a connecting pipe 200c may be connected to the lateral side of the combustion chamber 110 to be separated from the center of the cross-section of the combustion chamber 110. Therefore, the exhaust gas will be swirled along the inner wall of the combustion chamber 110 when the exhaust gas flows into the combustion chamber 110. As shown in FIG. 15, a supplementary air inflow line 115 may be further disposed to form a passage to flow an external air to the surface of the combustor 140. The supplementary external air flew through the supplementary air inflow line 115 is used with the burning external air when the burner is driven. Therefore, the flames can be further stably sustained. Also, a supplementary air s wirier 116 may be disposed between the inner wall of the supplementary air inflow line 114 and the combustor 140, and the supplementary air s wirier 116 swirls the supplementary external air flew into the surface of the combustor 140. That is, since the external air is swirled while flowing into the surface of the combustor 140, impurities such as carbon on the surface of the combustor 140 can be removed. Therefore, the ignition inferiority caused by the carbon attached on the surface of the combustor 140 can be improved and the heat may be uniformly and quickly spread out. FIGs 13 and 14 exemplary show the air inflow line 115 and the supplementary air s wirier 116 disposed with the connecting pipe 200c connected to be separated from the center of the cross-section of the combustion chamber 110. However, the air inflow line 115 and the supplementary air swirler 116 can be disposed although the connecting pipe is connected to a lateral side or a front side of the combustion chamber 110 as like as the connecting pipes 200a and 200b in order to further stably sustain the flames using the supplementary external air.

[50] Meanwhile, a numeral reference 117 denotes a supporting frame for firmly supporting the combustor 140, the igniter 150, the flame sensor 160, the clean air inflow line 152, 162, the flame holder 112, the swirler 113, 116 and the supplementary air inflow line 115.

[51] The burner 100 for regenerating the diesel engine particulate filter according to the present embodiment may be electrically feedback controlled by an electric control unit. Hereinafter, the feedback control operation of the electric control unit will be described with reference to FIG. 16.

[52] Referring to FIG. 16, an electric control unit 170 performs an electric feedback control to normally drive the constituent elements such as the combustion chamber 110, the carburetor 120, the mixed gas supplying unit 130, the combustor 140, the igniter 150, and the flame sensor 160.

[53] At first, the electric control unit 170 feedback controls the amount of flowing the external air for conveying and burning, the amount of flowing the flesh air, and the amount of flowing fuel in the fuel pump. In order to feedback control, electric valves 181, 182, 183 and 184 are disposed. The level of opening and closing the electric valves 181, 182, 183 and 184 are controlled through exchanging signals with the electric control unit 170. [54] Also, the electric control unit 170 feedback controls the temperature and the pressure of at least one spot in the combustion chamber 110, the temperature and the pressure of external air flew into the carburetor 123, the temperature and the pressure of external air flew into the mixed gas supplying unit 130, the temperature and the pressure of exhaust gas after passing the filter 410 in the particulate filter 400, and the temperature and the pressure of the carburetor 120. In order to feedback control, a plurality of temperature and pressure sensors 191, 192, 193, 194 and 195 are disposed. The temperature and pressure sensors 191, 192, 193, 194 and 195 transfer sensed signals to the electric control unit 170.

[55] Each constitutional element of the burner 100, such as the carburetor 120, the mixed gas supplying unit 130, the combustor 140, the igniter 150, and the flame sensor 160, is described as singular. However, the burner 100 may include multiple units for each constitutional element.

[56] Hereinafter, the operations of the burner 100 according to the present embodiment will be described with reference FIGs. 2, 3 and 16.

[57] When a diesel engine is driven, the exhaust gas outputted from the diesel engine flows into the combustion chamber 110 through the exhaust gas channel 300. Soot particles and SOF included in the exhaust gas are trapped in the filter 410 of the diesel particulate filter 400 which is disposed between the combustion chamber 110 and a discharging pipe 500. As the amount of soot particles trapped in the filter 410 increases, the pressure loss of the filter 410 gradually increases. The front end of the filter 410, which is the temperature and pressure sensor 191 in the combustion chamber 110, and the temperature and pressure sensor 194 of the filter 410 continuously transfer the pressure and temperature signals of the particulate filter 400 to the electric control unit 170. When the pressure difference between the front and the read end of the particulate filter 400 becomes greater than a predetermined threshold value, the burner 100 for regenerating the diesel particulate filter is driven as follows in response to an operation start signal from the electric control unit 170.

[58] When the fuel pump 121 is driven according to the operation start signal from the electric control unit 170, the atomizer 126 atomizes the liquid fuel and the atomized fuel flows into the gasifying chamber 123. The gasifying chamber 123 gasifies the fuel using the gasifying unit 125 such as a heater. The gaseous fuel is mixed with the air injected from the convey air inflow line 124. Then, the gaseous fuel mixed with the air flows into the mixing chamber 131 in the mixed gas supplying unit 130 through the fuel inflow line 133. Herein, the external air for burning flows into the mixing chamber 131 through the burning air inflow line 132. The gaseous fuel is mixed with the external air for burning, and the gaseous fuel mixed with the air is supplied into the combustor 140 of the combustion chamber 110 through the mixed gas inflow line 134. The mixed gas supplied to the combustor 140 is sprayed into the exhaust gas through the fine flame holes of porous material combustor 140. Herein, the igniter 150 receives the electric power from the power supply 153 and ignites the mixed gas to make flames on the surface of the combustor 140. After forming the flames on the surface of the combustor 140, the flame sensor 150 senses the flame and transfers a flame detecting signal to the electric control unit 170. The electric control unit 170 transmits a signal to the igniter 150 to turn off the igniter 150. Then, the flames are stably sustained on the combustor 140.

[59] The flame formed on the combustor 140 oxidizes the soot particles trapped in the diesel particulate filter 400 by increasing the temperature of the exhaust gas flowed into the combustion chamber 110 higher than the oxidization temperature of the soot particles. That is, the diesel particulate filter 400 is regenerated.

[60] If the pressure difference between the front and the rear of the diesel particulate filter 400 is smaller than the predetermined threshold value, the burner 100 according to the present embodiment is operated as follows according to an operation stop signal transmitted from the electric control signal.

[61] According to the operation stop signal from the electric control unit 170, the fuel pump 121 stops, and the carburetor 121 also stops. Also, according to the operations of the electric values 181, 182, 183 and 184 controlled by the electric control unit 170, the inflow of external air for conveying and burning stops so as to extinguish the flame on the combustor 140.

[62] As described above, the electric control unit 170 controls the burner 100 to ignite the flame, to sustain the flame and to extinguish the flame according to the pressure difference between the front and the read end of the diesel particulate filter 400 that traps the soot particles. Therefore, the regeneration of the diesel particulate filter 400 is stably performed even if the diesel engine is driving. Also, the electric control unit 170 automatically controls the amount of fuel and the amount of flowing air for burning and conveying to maintain the optimal state according to the driving condition variation of the diesel engine. Therefore, the flames on the combustor 140 are stably sustained without being extinguished.

[63] Furthermore, since the combustor 140 is made of porous material having a plurality of fine flame holes such as metal fibers, a plurality of short flames are formed at alla- tonceness. Also, the heat on the combustor 140 prevents the flame from being easily extinguished and quickly ignites flames all over the surface of the combustor 140. Because of the flame holder 112 having the porous sides surrounding the combustor 140 and the exhaust gas s wirier 113 swirling the exhaust gas, the surface of the combustor 140 is sufficiently heated even if the engine driving condition abruptly changes, for example, when the engine is accelerated and decelerated. Moreover, since the size of flame is very small, the variation thereof is also very small. Therefore, the flames on the combustor 140 are stably sustained although the amount of flowing the exhaust gas changes abruptly. That is, the burner according to the present invention stably sustains the flames on the combustor although the load variation of the diesel engine abruptly changes.

Claims

[1] A burner for regenerating a diesel engine particulate filter, comprising: a combustion chamber for receiving a exhaust gas from a diesel engine through at least one of connecting pipes connected to an exhaust gas channel of the diesel engine; a carburetor including a gasifying chamber for gasifying a liquid fuel, an atomizer for atomizing the liquid fuel into fine liquid drops and supplying the atomized liquid fuel to the gasifying chamber, and a convey air inflow line for forming a channel to flow an external air into the gasifying chamber for conveying the gasified fuel into a mixed gas supplying unit; a mixed gas supplying unit for mixing the gasified fuel from the gasifying chamber with an external air for burning, and supplying the mixed gaseous fuel to the combustion chamber; a combustor made of porous material and disposed in the combustion chamber for injecting the mixed gaseous fuel supplied from the mixed supplying unit; an igniter for igniting the mixed gaseous fuel injected from the combustor; and a flame sensor for sensing whether the flame is made on the surface of the combustor or not.

[2] The burner of claim 1, wherein the convey air inflow line has a predetermined portion disposed to pass the exhaust gas channel of the diesel engine for heating an external air flowing along the convey air inflow line through heat-exchanging with the exhaust gas outputted from the diesel engine and flowing the heated air into the gasifying chamber.

[3] The burner of claim 1, wherein the mixed gas supplying unit includes: a mixing chamber for forming a mixed gas by mixing an external air for burning and a gasified fuel; a burning air inflow line communicated with the mixing chamber for forming a channel for flowing an external air for burning into the mixing chamber; a fuel inflow line communicated with the mixing chamber and the gasifying chamber for forming a channel for flowing a gasified fuel into the mixing chamber; a mixed gas inflow line communicated with the mixing chamber and the combustion chamber for forming a channel for flowing the mixed gas from the mixing chamber into the combustion chamber.

[4] The burner of claim 3, wherein an external air inflow passage formed in the burning air inflow line and the mixing chamber are formed in a ventury shape that has a cross-section gradually reduced along the flow of the external air for burning.

[5] The burner of claim 3, wherein the burning air inflow line has a predetermined portion disposed to pass the exhaust gas channel of the diesel engine for heating an extern air flowing along the convey air inflow line through heat-exchanging with the exhaust gas outputted from the diesel engine and flowing the heated air into the mixing chamber.

[6] The burner of claim 1, further comprising an electric control unit for electrically feedback-controlling: a temperature and a pressure of at least one spot in the combustion chamber; an amount of flowing external air for conveying into the gasifying chamber, a temperature and pressure inside the gasifying chamber; a temperature, a pressure, and an amount of flowing an external air for burning into the mixed gas supplying unit; an amount of flowing a liquid fuel supplied from the fuel pump; a temperature and a pressure of an exhaust gas after passing through a diesel particulate filter; and operations of the combustor, the igniter, the flame sensor and the fuel pump.

[7] The burner of claim 6, wherein the gasifying unit includes: an electric valve for controlling an amount of external air for conveying, which is supplied through the convey air inflow line, in response to the electric control unit; and a temperature and pressure sensor for sensing a temperature and pressure in the gasifying chamber and providing the sensing signal to the electric control unit.

[8] The burner of claim 6, wherein the mixed gas supplying unit includes: an electric valve for controlling an amount of flowing an external air for burning, which is supplied through the burning air inflow line, in response to the electric control unit; and a temperature and pressure sensor for sensing a temperature and pressure of the external air for burning and providing the sensing signal to the electric control unit.

[9] The burner of claim 6, further comprising: a clean air supplying line communicated with an outside for supplying an external air into an ignite member of the igniter; and an electric valve for controlling an amount of flowing the external air supplied from the clean air supplying line in response to the electric control unit.

[10] The burner of claim 6, further comprising: a clean air supplying line communicated with an outside for supplying an external air to a flame sensing member of the flame sensor; and an electric valve for controlling an amount of flowing the external air supplied from the clean air supplying line in response to the electric control unit.

[11] The burner of claim 6, wherein the electric control unit drives the burner when a difference of pressures detected at a front and a rear of a diesel particulate filter is greater than a predetermined threshold, and stops the burner when the difference is smaller than the predetermined threshold.

[12] The burner of claim 1, wherein an inner surface of the combustion chamber is lined with at least one of ceramic wool, creak wool or fire brick.

[13] The burner of claim 1, wherein the porous material of the combustor is one selected from the group consisting of mat type metal fiber, ceramic and foam metal.

[14] The burner of claim 13, wherein the combustor has one of a cylinder shape, a cone shape, and a rectangle pipe shape.

[15] The burner of claim 1, wherein the combustor further includes a porous supporting member coupled to the inner side of the porous material for holding the shape of the porous material.

[16] The burner of claim 1, wherein the connecting pipe is connected to the side wall of the combustion chamber.

[17] The burner of claim 16, wherein the connecting pipe is connected to be separated from a center of a cross-section of the combustion chamber so as to swirl an exhaust gas along an inside wall of the combustion chamber.

[18] The burner of claim 1, wherein the connecting pipe is connected to a front wall of the combustion chamber.

[19] The burner of anyone of claims 16 to 18, further comprising: a supplementary air inflow line for forming a passage to flow a supplementary air into the surface of the combustor from the outside; and a supplementary air swirler disposed between the inside wall of the supplementary air inflow line and the surface of the combustor for swirling the supplementary external air to the surface of the combustor.

[20] The burner of anyone of claims 16 and 18, further comprising a porous cone shaped flame holder disposed to surround an external circumference of the combustor.

[21] The burner of claim 20, further comprising an exhaust gas swirler disposed between the inside wall of the flame holder and the surface of the combustor for swirling the exhaust gas flew into the combustion chamber.

[22] The burner of claim 21, further comprising a guide plate vertically disposed at one end of the flame holder for guiding an exhaust gas, which is flew into the combustion chamber, to pass the exhaust gas swirler.