US20100146939A1

US20100146939A1 - Inner flame burner for regeneration of diesel particulate filter

Info

Publication number: US20100146939A1
Application number: US11/993,728
Authority: US
Inventors: Seong Hun Sim; Seong Hyun Jeong; Won Seok Hong
Original assignee: Korea Institute of Machinery and Materials KIMM
Current assignee: Korea Institute of Machinery and Materials KIMM
Priority date: 2005-07-22
Filing date: 2006-06-21
Publication date: 2010-06-17
Also published as: KR100548451B1; WO2007011113A1

Abstract

Provided is a burner for regenerating a diesel engine particulate filter. The burner includes: a combustion chamber for receiving exhaust gas from a diesel engine; a carburetor for gasifying liquid fuel; a mixed gas supplying unit for mixing the gasified fuel with an external air, and supplying the mixed gaseous fuel to the combustion chamber; a mixed gas storing chamber disposed in the combustion chamber for receiving the mixed gaseous fuel and instantly storing the received mixed gaseous fuel; an inner flame combustor made of porous material for injecting the mixed gaseous fuel toward the inside of the inner flame combustor, and disposed in the combustion chamber to allow an exhaust gas to flow through the inner flame combustor; an igniter for igniting the mixed gaseous fuel; and a flame sensor for sensing the flame on the inner flame combustor.

Description

TECHNICAL FIELD

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

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.
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.
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.
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.
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.
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 600° C., 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 I 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.
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.
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

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.

Technical Solution

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; a mixed gas supplying unit for mixing the gasified fuel from the carburetor with an external air for burning, and supplying the mixed gaseous fuel to the combustion chamber; a mixed gas storing chamber disposed in the combustion chamber for receiving the mixed gaseous fuel from the mixed gas supplying unit and instantly storing the received mixed gaseous fuel; an inner flame combustor made of porous material for injecting the mixed gaseous fuel supplied from the mixed gas storing chamber in a direction from the outside to the inside of the inner flame combustor, and disposed in the combustion chamber to allow an exhaust gas to flow through the inner flame combustor; an igniter for igniting the mixed gaseous fuel injected toward the inside of the inner flame combustor; and a flame sensor for sensing whether the flame is made on the surface of the inner flame combustor or not.
The burner may further include at least one of swirlers disposed at an inlet of the combustion chamber to swirl the exhaust gas so as to flow the exhaust gas into the inside of the inner flame combustor while the exhaust gas swirling.
The connecting pipe may be disposed in a tangential direction from the cross section of the combustion chamber in order to flow the exhaust gas into the inner flame combustor disposed in the combustion chamber.
The inner flame burner may have a cyclone shape.
The burner may further include a gas-flow uniform unit disposed between the mixed gas supplying unit and the mixed gas storing chamber in an annular shape that forms a concentric circle with the combustion chamber for making the mixed gas to uniformly flow into the mixed gas storing chamber in a radial direction of the combustion chamber.
The burner may further include a flow-rate uniform unit for making a flow-rate of a mixed gas uniform in a length direction of the mixed gas by sustaining the pressure distribution of the mixed gas uniformly in the length direction of the inner flame combustor.
The carburetor may include: 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.
The convey air inflow line may have 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 gasifying chamber.
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; 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 mixed gas storing chamber.
An external air inflow passage formed in the burning air inflow line and the mixing chamber may be formed in a ventury shape that has a cross-section gradually reduced along the flow of the external air for burning.
The burning air inflow line may have 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 mixing chamber.
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.
The gasifying unit may include: 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.
The mixed gas supplying unit may include: 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.
The burner may further include: 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.
The burner may further include: 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.
The electric control unit may drive the burner when a difference of pressures detected at a front and a rear of a diesel particulate filter is greater than a pre-determined threshold, and stops the burner when the difference is smaller than the pre-determined threshold.
An inner surface of the combustion chamber may be lined with at least one of ceramic wool, creak wool or fire brick.
The porous material of the combustor may be one selected from the group consisting of mat type metal fiber, ceramic and foam metal.
The inner flame combustor may have one selected from the group consisting of a cylinder shape, a cone shape, a rectangle pipe shape, and combination thereof, which include a hollow hole defining the exhaust gas channel.
The burner may further include a heat resistant metal mash separately disposed inside the inner flame combustor for radiant heat-exchanging with the inside surface of the inner flame combustor.
The inner flame combustor may further include a porous supporting member for holding the shape of the porous material by being connected to the outer surface of the porous material.
The igniter may be one of a spark plug for igniting the mixed gas by generating electrical sparks, and a grow plug for accumulating heat at the one end.

Advantageous Effects

A burner for regenerating a diesel particulate filter according to the present invention has following advantages.
At first, the burner according to the present invention can instantly ignite and extinguish flames because the burner includes an inner flame combustor that is formed of porous metal fiber having a plurality of fine flame holes. After forming the flame on the inner flame combustor, the burner can stably sustain the flames in the flow of exhaust gas when the exhaust gas flows into a combustion chamber, when the engine is kept ticking over, when the engine is driven at a constant speed. Also, the inner flame burner according to the present invention can sustain the flame stably while the exhaust gas outputted from the diesel engine flows into the combustion chamber, and when the amount of flowing the exhaust gas and the pressure thereof abruptly change due to the abrupt variation of the load of the diesel engine.
Since the burner according to the present invention includes the inner flame combustor having a comparatively larger surface by forming the inner flame combustor made of porous material in a cylinder shape, and a rectangle pipe shape, the heat can be transferred quickly from the flames to the exhaust gas, and the constant temperature is uniformly sustained in the combustion chamber.
Furthermore, the burner according to the present invention swirls the exhaust gas to move soot particles in the exhaust gas toward the edges of the flow of the exhaust gas and forms the flames along the edges to effectively oxidize the soot particles so as to reduce the concentration of the soot particles in the exhaust gas that flows into the filter. Therefore, the life time of the filter is lengthened because the low concentrated exhaust gas flows into the filter, and the amount of fuel wasted for forming flames is reduced because the burning interval of the burner is also lengthened.
In addition, 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.
Moreover, the burner according to the present invention effectively regenerates a diesel particulate filter by stably sustaining the flames. Therefore, the burner can effectively prevent the environmental pollution caused by the exhaust gas.
Finally, the burner according to the present invention can be used to regenerate a particulate filter in diesel engines which are equipped 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

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:

FIG. 1 is a diagram a conventional diesel particulate filter;

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

FIG. 3 is a diagram illustrating a diesel particulate filter having a burner for regenerating the diesel particulate filter according to the second embodiment of the present invention; and

FIGS. 4 through 7 show a burner for regenerating a diesel particulate filter according to the third embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

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.
FIG. 2 is a diagram illustrating a diesel particulate filter having a burner for regenerating the diesel particulate filter according to the first embodiment of the present invention.
Referring to FIG. 2, the burner for regenerating the diesel particulate filter according to the first embodiment includes one end connected to an exhaust gas channel through at least one of connecting pipes 131 and other end connected to a particulate filtering device such as a filter 140 for collecting soot particles. The burner according to the first embodiment includes an inner flame combustor 100 made of porous mat type metal fiber for burning gasified fuel, a carburetor 120 for gasifying fuel to supply the gasified fuel to the inner flame combustor 100, a mixed gas supplying unit 110 for mixing the gasified fuel from the carburetor 120 and an external air for burning and supplying the mixed gas to the inner flame combustor 100, a combustion chamber 130 where the inner flame combustor 100 is disposed and receives an exhaust gas from a diesel engine, and an electric control unit 160 for electrically controlling the burner.
The inner flame combustor 100 is made of porous material in order to inject the mixed gas, which is supplied into the combustion chamber 130, in a direction from the outside to the inside thereof. The inner flame combustor 100 is disposed in the combustion chamber 130 so as to flow the exhaust gas from the connected pipe 131 into the inside thereof. The porous material of the inner flame combustor 100 may be mat type metal fiber, foam metal and ceramic which have high heat resistant characteristics. Herein, the inner flame combustor 100 may further include a porous supporting member 106 for holding the shape of the porous material by being coupled to the outside of the porous material.
Meanwhile, a heat resistant metal mash 107 may be disposed inside the inner flame combustor 100 to be separated from the inner side of the inner flame combustor 100. The heat resistant metal mash 107 may extremely raise the temperature of the exhaust gas that flows around the heat resistant metal mash 107 through radiant heat-exchanging with the inside of the inner flame combustor 100.
The carburetor 120 includes a gasifying chamber 121 for gasifying a liquid fuel, an atomizer 122 for atomizing liquid fuel such as diesel, which is pumped from a fuel tank (not shown) by a fuel pump 128, into fine liquid drops and supplying the atomized fuel, a heat source 123 for supplying heat for gasifying the fuel, a temperature and pressure sensor 124 for sensing the temperature and pressure of the atomizer 121 and supplying the sensed signal to the electric control unit 160, a convey air inflow line 125 for forming a passage to flow an external air to the gasifying chamber 121 in order to partially mix the gasified fuel with the air and to convey the gasified fuel, an electric valve 126 for electrically controlling the amount of flowing the external air, which is supplied through the convey air inflow line 125, and a liquid drop convey line 127 for flowing the liquid drops of atomized fuel from the atomizer 122 to the gasifying chamber 121.
The mixed gas supplying unit 110 mixes the gasified fuel from the carburetor 120 and the external air for burning, and supplying the mixed air to the inner flame combustor 100. the mixed gas supplying unit 100 includes a mixing chamber 111 for forming the mixed gas by mixing an external air with the gasified fuel, a burning air inflow line 112 communicated with the mixing chamber 111 for forming a passage for flowing an air into the mixing chamber 111, a fuel inflow line 113 communicated with the mixing chamber 111 and the gasifying chamber 121 for forming a passage to flow the mixed gas into the mixing chamber 11, and a mixed gas inflow line 114 communicated with the mixing chamber 111 and the combustion chamber 130 for forming a passage to flow the mixed gas into the combustion chamber 130. Herein, the passages for flowing the external air for burning to the mixing chamber 111 through the burning air inflow line 112 is formed in a ventury shape that has a gradually reduced cross-section. By forming the passage in the ventury shape, the mixed gas formed at the gasifying chamber 121 of the carburetor 120 smoothly moves to the mixing chamber 111 of the mixed gas supplying unit 110. Therefore, the mixed gas made of the fuel and the air is smoothly supplied to the inner flame combustor 100.
A gas-flow uniform unit 133 makes the mixed gas to flow from the mixed gas supplying unit 110 into a mixed gas storing chamber 134 uniformly in a radial direction of the combustion chamber. The gas-flow uniform unit 133 has an annular shape that forms the concentric circle with the inner surface of the combustion chamber 130 and is made of porous material such as honeycomb. The gas-flow uniform unit 133 makes the mixed gas to flow uniformly into the mixed gas storing chamber 134. Then, the mixed gas is injected through the surface of the inner flame combustor 100 that is disposed in the combustion chamber and made of porous material. When the mixed gas is injected through the inner flame combustor 100, the igniter 101 ignites the mixed gas injected from the surface of the inner flame combustor 100 to the inside thereof through electric discharging. Then, the flames are formed on the inner flame combustor 100 toward the inside of the inner flame combustor 100.
The ignite performance of the igniter 101 may be degraded by pollution such as soot particles. Therefore, a grow plug may be used as the igniter 101. The grow plug ignites the mixed gas by accumulating heat at the one end thereof. If a spark plug, which ignites the mixed gas by generating the electrical sparks, is used as the igniter 101, the igniter 101 must be sustained as clean. In order to sustain the igniter 101 to be clean, a clean air supplying line 104 may be further included to supply clean external air to the igniter 101. Also, since the igniter 101 must be stopped when the flames are formed on the inner flame combustor 100, a flame sensor 103 is disposed. In order to sustain the flame sensor 103 or a flame sensing member of the flame sensor 103 to be clean, a clean air inflow line 104 may be further included for supplying fresh air.
The combustion chamber 130, which provides a space for receiving the exhaust gas from the diesel engine, includes a fireproof thermal insulator 132 for thermally insulating all walls that contact the external environment. In the combustion chamber 130, a temperature and pressure sensor 138 for sensing a temperature and pressure in the combustion chamber 130 is disposed and a connecting pipe 131 is connected as an exhaust gas passage. Also, the elements of the burner such as the inner flame combustor 100, the igniter 101, the flame sensor 103 and the clean air inflow line 104 are disposed in the combustion chamber 130.
Meanwhile, electric valves 126, 115, 105 and 129 are disposed to control the amount of flowing an external air for conveying, the amount of flowing an external air for burning, the amount of flowing a clean air, and the amount of flowing the fuel in the fuel pump. The levels of opening and closing the electric valves 126, 115, 105 and 129 are controlled by the electric control unit 160 through exchanging the sensing signals with the electric control unit 160. The electric control unit 160 feedback controls the operations of the igniter 101, the power supply 102, and the flame sensor 103, and the sensing and control operations of the temperature and pressure sensor 138 in the carburetor 120 in order to normally drive the elements.
Hereinafter, the operation of the burner according to the present invention will be described.
When a diesel engine is driven, an exhaust gas passes the inside of the inner flame combustor 100 disposed in the combustion chamber 130 along the connecting pipe 131 and is outputted through a discharging pipe 150. While the exhaust gas passes, the Soot particles and SOF included in the exhaust gas are trapped in a diesel particulate filter 140 which is disposed between the combustion chamber 130 and the discharging pipe 150. As the amount of soot particles trapped in the diesel particulate filter 140 increases, the pressure loss of the diesel particulate filter 140 gradually increases. The temperature and pressure sensor 138 disposed at the front end of the diesel particulate filter 140, and the temperature and pressure sensor 141 disposed at the rear end of the diesel particulate filter 140 continuously transfer the pressure and temperature signals of the particulate filter 140 to the electric control unit 160. When the pressure difference between the front and the rear end of the particulate filter 140 becomes greater than a predetermined threshold value, the burner is driven as follows in response to an operation start signal from the electric control unit 160.
When the fuel pump 121 is driven according to the operation start signal from the electric control unit 160, the atomizer 122 atomizes the liquid fuel and the atomized fuel flows into the gasifying chamber 121. The gasifying chamber 121 gasifies the fuel using the gasifying heat source 123. The gaseous fuel is mixed with the air injected from the convey air inflow line 125. Then, the gaseous fuel mixed with the air flows into the mixing chamber 111 in the mixed gas supplying unit 110 through the fuel inflow line 113. Herein, the external air for burning flows into the mixing chamber 111. As a result, the mixed gas is supplied to the inner flame combustor 100 quantitatively by storing the mixed gas in the mixed gas storing chamber 123 through the gas-flow uniform unit 133. Then, the mixed gas is injected into the exhaust gas flowing inside the inner flame combustor 100. Herein, the power is supplied to the igniter 101 from the high voltage power supply 102, and the igniter 101 ignites the mixed gas so as to form flames in a direction from the surface of the inner flame combustor 100 toward the inside of the combustion chamber.
After forming the flames on the inner flame combustor 100, the flame sensor 103 transmits a flame detecting signal to the electric control unit 160, and the igniter 101 is stopped in response to a signal transmitted from the electric control unit 160. Then, the flames are stably sustained on the inner flame combustor 100.
The flame formed on the inner flame combustor 100 oxidizes the soot particles trapped in the diesel particulate filter 140 by increasing the temperature of the exhaust gas flowing through the combustion chamber 130 higher than the oxidization temperature of the soot particles. That is, the diesel particulate filter 140 is regenerated.
If the pressure difference between the front and the rear end of the diesel particulate filter 140 returns to an original state, the electric control unit 160 stops the fuel pump 128. Accordingly, the carburetor 120 also stops. According to the operations of the electric values 126, 115, 105 and 129, the inflow of external air for conveying and burning also stops so as to extinguish the flame on the inner flame combustor 100. As described above, the electric control unit 160 controls the burner to ignite the flame, to sustain the flame stably and to extinguish the flame according to the pressure difference between the front and the read end of the diesel particulate filter 140 that traps the soot particles. Therefore, the regeneration of the diesel particulate filter 140 is stably performed even if the diesel engine is driving.
Also, the electric control unit 160 automatically controls the amount of fuel, the amount of flowing the air for conveying and burning to be the optimal state according to the driving condition variation of the diesel engine. Therefore, the flames on the inner flame combustor 100 can be stably sustained without being extinguished although the driving condition of the diesel engine abruptly changes.
Meanwhile, the most of conventional burners for regenerating a diesel particulate filter are a liquid fuel injection type burner that often unintentionally extinguishes the flames or cannot sustain the flames stably when the load variation of the diesel engine abruptly changes. Therefore, the most of the conventional burners is driven only 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. Therefore, the conventional burner cannot be used for regeneration practically.
However, in the present invention, since the inner flame combustor 100 is made of porous material having a plurality of fine flame holes such as metal fibers, a plurality of short flames are formed at allatonceness. Also, the heat on the inner flame combustor 100 prevents the flames from being easily extinguished and quickly ignites flames all over the surface of the inner flame combustor 100. Since the flames on the inner flame combustor 100 are formed along the edges of the exhaust gas flow, the flames can sufficiently heat the inner flame combustor 100 although the driving condition of the diesel engine and the amount of flowing the exhaust gas abruptly change. Moreover, since the size of flame is very small, the variation thereof is also very small. Therefore, the flames on the inner flame combustor 100 are stably sustained.
When the exhaust gas flows into the inside of the inner flame combustor 100 disposed in the combustion chamber 130 after forming the flame on the inner flame combustor 100, the burner according to the first embodiment can ignite, extinguish and stably sustain the flames in the flow of exhaust gas when the exhaust gas flows into a combustion chamber, when the engine is kept ticking over, when the engine is driven at a constant speed. Also, the burner according to the first embodiment can sustain the flame stably while the exhaust gas outputted from the diesel engine flows into the combustion chamber, and when the amount of flowing the exhaust gas and the pressure thereof abruptly change due to the abrupt variation of the load of the diesel engine.
While the burner according to the present invention has been described with respect to the first embodiment, it will be apparent to those skilled in the art that various changes and modifications may be made. That is, the burner according to the present invention may include various embodiments that gasifies a liquid fuel, injects the gasified fuel through the inner flame combustor 100 which is made of porous material and disposed along the edges of the combustion chamber where the exhaust gas flows into, and ignites the gasified fuel to form flames on the inner flame combustor 100 so as to transfer the heat from the edges of the exhaust gas to the center area by the flames. Herein, the porous material may be porous metal mat, metal fiber mat, porous ceramic, foam metal and foam ceramic.
Also, an ultrasonic liquid fuel atomizer 122 may be disposed between the fuel pump 128 and the gasifying chamber 121 to improve the gasifying performance. Although the ultrasonic liquid fuel atomizer 122 is not included, the object of the present invention can be archived through using the liquid fuel carburetor. Furthermore, various units that gasify liquid fuel although the heat source is not used to gasify the liquid fuel may be used as the carburetor in the present invention.
In the first embodiment of the present invention, the external air flew into the gasifying chamber 121 and the mixing chamber 111 is described as the normal temperature air. However, the burner according to the present invention may pre-heat the external air by guiding the external air to pass through the exhaust gas outputted from the engine before flowing into the gasifying chamber 121 and the mixing chamber 111. That is, the external air may be heated by heat-exchanging with the exhaust gas while passing the exhaust gas.
In the first embodiment of the present invention, the inner flame combustor 100 has a cylinder shape. However, the present invention is not limited thereby. It is obvious to those skilled in the art that the inner flame combustor 100 may have any shapes that allows the exhaust gas to pass through the hollow hole of the inner flame combustor 100 to the diesel particulate filter.
Furthermore, the inner flame combustor 100 according to the first embodiment is formed of porous metal fiber in a mat shape. However, the inner flame combustor 100 may be formed of porous metal, foam metal, porous ceramic or other high heat resistant porous materials. Hereinafter, a burner for regenerating a diesel particulate filter according to the second embodiment of the present invention will be described with reference to FIG. 3. Since the burner according to the second embodiment has the similar structure compared to the burner according to the first embodiment, the detailed descriptions of identical elements will be omitted.
The burner according to the first embodiment has a structure that instantly stores gasified fuel from the carburetor into the mixed gas storing chamber 134 through the gas-flow uniform unit 133 as shown in FIG. 2. However, the burner according to the second embodiment, as shown in FIG. 3, additionally includes a flow-rate uniform unit 135 in the mixed gas storing chamber 134.
When the mixed gas is injected from the mixed gas storing chamber 134 to the inside of the inner flame combustor 100, the injecting speeds in the length direction of the inner flame combustor 100 are generally different at spots in the length direction of the inner flame combustor 100.
That is, the injecting speeds become varied by the influence of the pressure distribution in the length direction of the mixed gas storing chamber because the distance between the inner flame combustor 100 and the side wall of the combustion chamber 130 is constant. In the burner according to the second embodiment, the flow-rate uniform unit 135 disposed in the mixed gas storing chamber 134 for eliminating the influence of the pressure distribution in the length direction.
Hereinafter, a burner for regenerating a diesel particulate filter according to the third embodiment of the present invention will be described with reference to FIGS. 4 through 7. Since the burner according to the third embodiment has the similar structure compared to the burners according to the first and the second embodiments, the detailed descriptions of the identical elements will be omitted.
When the exhaust gas flows from the diesel engine into the combustion chamber, the burner according to the third embodiment swirls the exhaust gas in order to maximize the regeneration efficiency.
Since the flames formed on the inner flame combustor 100 are formed along edges of the combustion chamber 130, which is the outside of the exhaust gas flow, the flames are not influenced by the exhaust gas flow variation. The heat is transferred from the flames to the exhaust gas mainly through radiant heat-exchanging with a convention current. Herein, the heat transfer mechanism between the flames and the exhaust gas significantly influences the level of increasing an exhaust gas temperature and the time of increasing the exhaust gas temperature. If the flow of the exhaust gas is swirling, the heat transfer mechanism may have superior characteristics in the view of heat and material transfer. The centrifugal force made by swirling moves soot particles in the exhaust gas to the edges of the combustion chamber 130. Since the flames are formed along the edges of the combustion chamber 130, the soot particles in the exhaust gas are effectively oxidized. Finally, the concentration of the soot particles in the exhaust gas becomes reduced when the exhaust gas enters the filter 140. Accordingly, the filter 140 collects less amount of soot particles until the pressure difference of the filter 140 reaches at a predetermined threshold value. Therefore, the life time of the filter 140 becomes significantly lengthened, and the performance thereof is also improved.
That is, the burning interval of the burner for the identical pressure difference becomes extended so the life time of the filter 140 is significantly lengthened. The amount of fuel used is also significantly reduced in proportional to the lengthened burning interval.
Swirling the exhaust gas as described above can be achieved by modifying the configuration of the burner according to the present invention as follows.
At first, as shown in FIG. 4, a burner for regenerating a diesel particulate filter may be configured to have the above mentioned advantages by disposing a swirler 136 at the inlet of the combustion chamber 130. The swirler 136 swirls the exhaust gas flew into the combustion chamber 130. Then, the swirling exhaust gas flows into the combustion chamber 130. The burner may additionally include the flow-rate uniform unit 135 for eliminating the influence of the pressure distribution in the length direction, which is included in the burner according to the second embodiment as shown in FIG. 3, in the mixed gas storing chamber 134 with the configuration that instantly stores the gasified fuel from the carburetor 120 in the mixed gas storing chamber 134 through the gas-flow uniform unit 133 as shown in FIG. 5.
Secondly, as shown in FIG. 6, a burner for regenerating a diesel particulate filter may be configured to have the above mentioned advantages by disposing the connecting pipe 137 in a tangential direction for the cross section of the combustion chamber 130 in order to flow the exhaust gas in the tangential direction of the combustion chamber 130. According to this configuration, the exhaust gas flows into the combustion chamber 130 while the exhaust gas is swirling. Preferably, the burner may additionally include the flow-rate uniform unit 135 in the mixed gas storing chamber 134 for eliminating the influence of the pressure distribution in the length direction with the structure that instantly stores the gasified fuel from the carburetor 120 in the mixed gas storing chamber 134 through the gas-flow uniform unit 133 as shown in FIG. 2.
Thirdly, as shown in FIG. 7, a burner for regenerating a diesel particulate filter may be configured to have the above mentioned advantages by disposing the connecting pipe 137 in the tangential direction from the cross section of the combustion chamber 130 in order to flow the exhaust gas in the tangential direction of the combustion chamber 130, and forming the inner flame combustor 100 in a cyclone shape that maximally uses the centrifugal force. In this case, a negative pressure is formed in the combustion chamber, and the negative pressure attenuates the pressure increment when the engine loads varies by the abrupt variation of driving conditions of the diesel engine. Therefore, the flames are further stably sustained although the engine load changes abruptly. Furthermore, it is preferable that the burner may additionally include the flow-rate uniform unit 135 having the identical shape of the cyclone shape of the inner flame combustor 100 for removing the influence of the pressure distribution in the length direction with the structures that instantly stores the gasified fuel from the carburetor 120 in the mixed gas storing chamber 134 through the gas-flow uniform unit 133.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

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 for gasifying liquid fuel; a mixed gas supplying unit for mixing the gasified fuel from the carburetor with an external air for burning, and supplying the mixed gaseous fuel to the combustion chamber; a mixed gas storing chamber disposed in the combustion chamber for receiving the mixed gaseous fuel from the mixed gas supplying unit and instantly storing the received mixed gaseous fuel; an inner flame combustor made of porous material for injecting the mixed gaseous fuel supplied from the mixed gas storing chamber in a direction from the outside to the inside of the inner flame combustor, and disposed in the combustion chamber to allow an exhaust gas to flow through the inner flame combustor; an igniter for igniting the mixed gaseous fuel injected toward the inside of the inner flame combustor; and a flame sensor for sensing whether the flame is made on the surface of the inner flame combustor or not.

2. The burner of claim 1, further comprising at least one of swirlers disposed at an inlet of the combustion chamber to swirl the exhaust gas so as to flow the exhaust gas into the inside of the inner flame combustor while the exhaust gas swirling.

3. The burner of claim 1, wherein the connecting pipe is disposed in a tangential direction from the cross section of the combustion chamber in order to flow the exhaust gas into the inner flame combustor disposed in the combustion chamber.

4. The burner of claim 1 wherein the inner flame burner has a cyclone shape.

5. The burner according to claim 1, further comprising a gas-flow uniform unit disposed between the mixed gas supplying unit and the mixed gas storing chamber in an annular shape that forms a concentric circle with the combustion chamber for making the mixed gas to uniformly flow into the mixed gas storing chamber in a radial direction of the combustion chamber.

6. The burner of claim 5, further comprising a flow-rate uniform unit for making a flow-rate of a mixed gas uniform in a length direction of the mixed gas by sustaining the pressure distribution of the mixed gas uniformly in the length direction of the inner flame combustor.

7. The burner of claim 1, wherein the carburetor 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.

8. The burner of claim 7, 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.

9. The burner of claim 7, 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 mixed gas storing chamber for forming a channel for flowing the mixed gas from the mixing chamber into the mixed gas storing chamber.

10. The burner of claim 9, 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.

11. The burner of claim 9, wherein the burning 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 mixing chamber.

12. The burner of claim 7, 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.

13. The burner of claim 12, 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.

14. The burner of claim 12, 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.

15. The burner of claim 12, 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.

16. The burner of claim 12, 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.

17. The burner of claim 12, 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.

18. 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.

19. 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.

20. The burner of claim 19, wherein the inner flame combustor has one selected from the group consisting of a cylinder shape, a cone shape, a rectangle pipe shape, and combination thereof, which include a hollow hole defining the exhaust gas channel.

21. The burner of claim 1, further comprising a heat resistant metal mash separately disposed inside the inner flame combustor for radiant heat-exchanging with the inside surface of the inner flame combustor.

22. The burner of claim 1, wherein the inner flame combustor further includes a porous supporting member for holding the shape of the porous material by being connected to the outer surface of the porous material.

23. The burner of claim 1, wherein the igniter is one of a spark plug for igniting the mixed gas by generating electrical sparks, and a grow plug for accumulating heat at the one end.