JP2005307842A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase an exhaust gas temperature by supplying combustion gas and increase a temperature in the vicinity of the outer wall of a particulate filter to a temperature necessary for filter regeneration. <P>SOLUTION: This exhaust emission control device 1 in which particulates in exhaust gas G2 from a diesel engine 101 are collected by the particulate filter 2 is provided with a hollow member 10 for forming a chamber 9 at the inlet side of the particulate filter 2, a supplying device 3 for supplying combustion gas G1, a combustion gas introducing port 91 for supplying the combustion gas G1 into the chamber 9, and an exhaust gas introducing port 92 for introducing the exhaust gas G2 into the chamber 9 so that a revolving flow revolving around an axis line of the particulate filter 2 is formed in the chamber 9. Since the revolving flow of exhaust gas G1 is formed in the chamber 9, the entire particulate filter 2 can be heated uniformly. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust emission control device for treating diesel particulate (PM) contained in exhaust gas.

  Various exhaust gas aftertreatment devices have been developed in which PM contained in diesel engine exhaust gas is collected by a diesel particulate filter (DPF) and the collected PM is rendered harmless by appropriate means. Yes. In the exhaust gas aftertreatment device having such a configuration, the amount of PM accumulated in the DPF increases as the collection of PM proceeds, thereby increasing the back pressure of the diesel engine and lowering the operation efficiency of the diesel engine. Will do.

  In order to prevent this, it is necessary to periodically remove the PM accumulated in the DPF. However, since the exhaust gas of the diesel engine has few opportunities to rise to the high temperature necessary to remove the PM accumulated in the DPF, the DPF A system for heating the exhaust gas during regeneration, a system for reducing the regeneration temperature by combining a catalyst, and a system combining these have been proposed.

  For example, Patent Document 1 discloses a filter regeneration device including a regeneration burner that generates high-temperature gas to regenerate a DPF. The burner exhaust gas and engine exhaust gas are mixed by a mixer, and thus obtained. A configuration has been proposed in which a high-temperature mixed gas is fed into the DPF.

On the other hand, Patent Document 2 discloses an inlet pipe having a small-diameter throttle passage at the center and a burner combustion chamber and a gas induction chamber extending outwardly before and after the front side of the filter casing containing the filter member therein. A configuration in which an exhaust introduction pipe is disposed along the filter casing in the center of the front of the burner combustion chamber, and a plurality of burners are disposed so as to be inclined so that their tips approach the axis. Is disclosed.
Japanese Patent Publication No. 6-27500 No. 6-6180

  However, according to the prior art disclosed in Patent Document 1, a separate mixer is provided on the inlet side of the filter container, whereby the burner exhaust gas and the engine exhaust gas are mixed to obtain a total exhaust gas of 500 to 600 ° C. Although the configuration is such that all exhaust gas is supplied to the particulate filter, the configuration is complicated, the cost is increased, and the temperature in the vicinity of the outer wall of the particulate filter cannot always be increased to the temperature necessary for filter regeneration. have.

  On the other hand, according to the prior art disclosed in Patent Document 2, since the flame of the burner and the exhaust gas are passed through the throttle passage together, they are mixed and sent to the filter casing. It has the same problem as in the case of this technology.

  An object of the present invention is to provide an exhaust emission control device capable of solving the above-described problems in the prior art.

  A feature of the present invention for solving the above-described problems is that, in an exhaust gas purification apparatus in which particulates in exhaust gas from an internal combustion engine are collected by a particulate filter, a cylindrical chamber is provided on the inlet side of the particulate filter. , A supply device for supplying combustion gas, a combustion gas introduction port provided in the hollow member for supplying the combustion gas into the chamber, and an axis of the particulate filter And an exhaust gas introduction port provided in the hollow member for introducing the exhaust gas into the chamber so that a swirling flow swirling around is formed in the chamber.

  According to the present invention, the exhaust gas and the combustion gas are mixed in the chamber, and the mixed gas is swirled in the chamber and given to the particulate filter. The particulate filter can be effectively regenerated.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an example of an embodiment of an exhaust emission control device according to the present invention. The exhaust purification device 1 is attached to an exhaust pipe 102 connected to an exhaust manifold (not shown) of a diesel engine 101, and a catalyst regeneration type is used to convert PM contained in exhaust gas G2 from the exhaust pipe 102. It is configured as a continuous regeneration type device that is collected and processed by a particulate filter.

  The particulate filter 2 is in the form of a wall flow, and has a configuration in which an oxidation catalyst 22 is provided on the exhaust gas upstream side of the filter 21 for collecting PM. The filter 21 may be coated with a catalyst. Moreover, when using such a thing, the structure without the oxidation catalyst 22 of the front | former stage may be sufficient.

  The particulate filter 2 includes a first pressure sensor 23 for detecting the inlet side pressure, a second pressure sensor 24 for detecting the outlet side pressure, a first temperature sensor 25 for detecting the inlet side temperature, A second temperature sensor 26 for detecting the temperature between the filter 21 and the oxidation catalyst 22, a third temperature sensor 27 for detecting the temperature on the outlet side, and an oxygen temperature in the exhaust gas on the outlet side. The oxygen sensor 28 is provided.

  The output signals of these sensors 23 to 28 are input to the controller 4. A signal L indicating the operation state of the diesel engine 101 is input to the controller 4 from the engine control unit 103 for electronically controlling the diesel engine 101. The controller 4 is configured to control the operation of the supply device 3 based on these signals.

  The supply device 3 includes a fuel injector 31 to which the fuel in the fuel tank 6 is supplied with a substantially constant pressure by the fuel pump 7 and the regulator 8, and the fuel injected from the fuel injector 31 is gasified by the evaporation device 32. The fuel is evaporated.

  The evaporating device 32 is for evaporating the fuel injected from the fuel injector 31 by heating, thereby gasifying the fuel to obtain evaporating fuel. The feeding device 33 uses compressed air from the air pump 34. Thus, the evaporated fuel from the evaporation device 32 is sent into the particulate filter 2 as an air-fuel mixture. What is indicated by reference numeral 35 is an ignition device for igniting the evaporated fuel in the feeding device 33.

  The operations of the fuel pump 7, the fuel injector 31, the evaporation device 32, the feeding device 33, the air pump 34, and the ignition device 35 are controlled by the control signals C7, C31, C32, C34, C35 from the controller 4, and the particulates. The filter 2 is always regenerated under optimum conditions.

  Since the supply device 3 is configured as described above, when the ignition operation by the ignition device 35 is not performed, the evaporated fuel is sent to the particulate filter 2 as raw fuel as it is. On the other hand, when the evaporated fuel is ignited by the ignition device 35, the combustion gas G1 generated thereby is sent to the particulate filter 2. That is, the supply device 3 is configured to be able to supply either raw fuel or combustion gas to the particulate filter 2 upstream of the particulate filter 2.

  In order to regenerate the particulate filter 2, the exhaust gas G 2 from the exhaust pipe 102 and the combustion gas G 1 from the supply device 3 can be efficiently supplied to the particulate filter 2. A hollow member 10 for forming a cylindrical chamber 9 is provided on the inlet side. In the present embodiment, a cylindrical tube having one end closed is provided as a hollow member 10 at the inlet end 2A of the particulate filter 2, and the opening at the other end is the inlet end 2A of the particulate filter 2. Thus, a chamber 9 is formed. The hollow member 10 is provided with a combustion gas introduction port 91 and an exhaust gas introduction port 92.

  FIG. 2 is a partial cross-sectional view showing a main part of FIG. The combustion gas introduction port 91 is formed as a cylindrical member provided at the closed end 10 </ b> A of the hollow member 10 so as to be substantially coaxial with the axis of the cylindrical chamber 9. The combustion gas introduction port 91 is provided with the feeding device 33 of the supply device 3. Therefore, the feeding device 33 faces the inlet end 2 </ b> A of the particulate filter 2 and is output from the feeding device 33. The combustion gas G <b> 1 is supplied toward the inlet end 2 </ b> A of the particulate filter 2 through the combustion gas introduction port 91. Here, the supply direction of the combustion gas G <b> 1 supplied from the combustion gas introduction port 91 into the chamber 9 is substantially perpendicular to the inlet side end face of the oxidation catalyst 22.

  On the other hand, the exhaust gas introduction port 92 is formed by attaching a cylindrical member to the peripheral wall of the hollow member 10. Here, the axis of the exhaust gas introduction port 92 is substantially orthogonal to the axis of the hollow member 10, that is, the chamber 9. Thus, the exhaust gas introduction port 92 is attached to the hollow member 10. Here, the inner diameter R92 of the exhaust gas introduction port 92 is set smaller than the inner diameter R10 of the hollow member 10. Therefore, when the exhaust gas G2 sent from the exhaust pipe 102 is introduced into the chamber 9 through the exhaust gas introduction port 92, the exhaust gas G2 is introduced into the chamber 9 in the form of a jet due to this inner diameter difference. Is done. As a result, the exhaust gas G2 is vigorously injected into the chamber 9 from the exhaust gas introduction port 92.

  FIG. 3 is a view for explaining the state of introduction of the exhaust gas G2 into the chamber 9. As shown in FIG. 3, the exhaust gas G2 is introduced into the chamber 9 so as to be jetted from the peripheral wall of the hollow member 10 in the radial direction of the chamber 9. After hitting the opposing inner peripheral surface, it flows in the circumferential direction along the inner peripheral surface of the hollow member 10 and becomes a swirling flow. This exhaust gas swirl flow becomes a swirl flow swirling around the axis of the hollow member 10 arranged coaxially with the particulate filter 2 in the chamber 9, that is, around the axis of the particulate filter 2.

  Then, when the combustion gas G1 from the supply device 3 is supplied into the chamber 9 from the combustion gas introduction port 91, the combustion gas G1 is blown in a direction orthogonal to the exhaust gas G2 that is a swirling flow. The exhaust gas G2 is heated by the combustion gas G1, and the exhaust gas G2 and the combustion gas G1 are well mixed by collision mixing in the chamber 9, and the mixed gas also becomes a swirl flow in the particulate filter 2. Flow into. At this time, the mixed gas passes through the particulate filter 2 in a spiral shape. Here, a part of the oxygen amount necessary for combustion is obtained from oxygen in the exhaust gas G2. The combustion gas G1 flows through the center of the chamber 9 and heats the filter.

  Since the heated exhaust gas G20 collides with the wall surface of the hollow member 10 and flows along the inner peripheral portion of the chamber 9, heat is transmitted to the outer peripheral portion of the particulate filter 2 that is not easily received heat and has a large heat loss. The temperature of G2 becomes uniform in the radial direction. In the broken line area, mixing and diffusion are promoted by a large velocity gradient.

  As a result, the mixed high-temperature gas can sufficiently generate a mixed gas flow near the outer peripheral wall of the particulate filter 2, and heating of the outer peripheral portion of the particulate filter 2 is intensively promoted, and the particulate filter Since the whole 2 can be heated substantially uniformly, only the vicinity of the central portion of the particulate filter 2 is heated, so that there is no problem that melting due to overheating occurs or the outer peripheral portion cannot be heated.

  Further, since PM deposited on the filter 21 of the particulate filter 2 has a tendency that exhaust gas flows through the outer peripheral portion, the PM deposition distribution in the radial direction is not uniform and is biased toward the outer peripheral portion. Therefore, even if the central portion is heated by a burner as in the conventional case, heat is not easily transmitted to the outer peripheral portion where a large amount of PM is accumulated, and the regeneration rate of PM may be deteriorated. When trying to raise the temperature above, the amount of energy input to the burner increases and a part that is overheated appears, so it is considered that the deterioration of the filter may be accelerated or damaged. Generation | occurrence | production of such a malfunction can be suppressed effectively and reduction of energy consumption can be aimed at.

  As described above, according to the exhaust purification device 1, the exhaust gas G2 of the diesel engine 101 can be effectively heated by disturbing the flow of the exhaust gas G2 inside the chamber 9, and the outer periphery of the particulate filter 2 having a large heat loss. Since the part can be positively heated by the heat obtained from the combustion gas G1 supplied by the supply device 3, it is possible to make the temperature distribution in the radial direction of the particulate filter 2 uniform.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment. In the present invention, it is desirable to cause the combustion gas G1 and the exhaust gas G2 to collide with each other within the chamber 9 at a substantially right angle or an angle close thereto, but the collision angle between the two gases is not limited to this.

  FIG. 4 is a diagram for explaining another embodiment of the present invention. Here, the exhaust gas G2 is introduced into the hollow member 10 along the inner peripheral surface thereof. Therefore, the direction in which the exhaust gas introduction port 92 ′ looks into the hollow member 10 is away from the axis of the chamber 9 compared to the case shown in FIG. 3.

  According to the configuration of FIG. 4, the exhaust gas G2 introduced into the chamber 9 can be more effectively swirled. Also in this case, since the combustion gas G1 collides with the exhaust gas G2 at an angle of substantially right angle, both can be mixed well.

  FIG. 5 is a view for explaining still another embodiment of the present invention. Here, in the configuration of FIG. 4, the introduction position of the combustion gas G1 into the chamber 9 is set from the axis of the chamber 9 to the hollow member 10. The combustion gas introduction port 91 'is provided near the outer peripheral wall of the hollow member 10 and near the exhaust gas introduction position. As a result, with respect to the exhaust gas G2 introduced into the chamber 9 from the exhaust gas introduction port 92 ′, the combustion gas G1 from the combustion gas introduction port 91 ′ is changed into the exhaust gas flow immediately after being introduced into the chamber 9. Colliding at substantially right angles, both gases collide and mix, and the mixed gas becomes a swirling flow in the chamber 9.

  FIG. 6 is a diagram showing a main part of still another embodiment of the present invention. 6, the same reference numerals are given to the portions corresponding to the respective portions in FIG. 2. Here, the combustion gas introduction port 93 is provided in the exhaust pipe 102, and the combustion gas G1 from the feeding device 33 of the supply device 3 is exhausted so as to be perpendicular to the flow direction of the exhaust gas G2 in the middle of the exhaust pipe 102. It is characterized in that it is introduced into the tube 102.

  According to this configuration, the combustion gas G1 and the exhaust gas G2 are collided and mixed in the exhaust pipe 102, and the high-temperature mixed gas produced thereby is introduced into the chamber 9 via the exhaust gas introduction port 92. Thus, a swirling flow is generated in the chamber 9 in the same manner as in FIG. 2 (see FIG. 7).

  In this case as well, as shown in FIG. 8, by making the mounting state of the exhaust gas introduction port 92 the same as in the case shown in FIG. .

The schematic block diagram which shows one Embodiment of this invention. The principal part partial sectional view which shows the principal part of FIG. The figure for demonstrating the introduction state to the chamber of the exhaust gas shown in FIG. The figure for demonstrating other embodiment of this invention. The figure for demonstrating another embodiment of this invention. The figure which shows the principal part of other embodiment of this invention. The figure for demonstrating the introduction state to the chamber of the exhaust gas shown in FIG. The figure for demonstrating the modification of embodiment of this invention shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust gas purification apparatus 2 Particulate filter 2A Inlet end 3 Supply apparatus 21 Filter 22 Oxidation catalyst 31 Fuel injector 32 Evaporator 33 Feeder 35 Ignition apparatus 91, 91 ', 93 Combustion gas introduction port 92, 92' Exhaust gas introduction port 101 Diesel engine 102 Exhaust pipe G1 Combustion gas G2 Exhaust gas

Claims (1)

In an exhaust emission control device configured to collect particulates in exhaust gas from an internal combustion engine by a particulate filter,
A hollow member for forming a cylindrical chamber on the inlet side of the particulate filter;
A supply device for supplying combustion gas;
A combustion gas introduction port provided in the hollow member for supplying the combustion gas into the chamber;
An exhaust gas purification apparatus comprising: an exhaust gas introduction port provided in the hollow member for introducing the exhaust gas into the chamber so that a swirling flow swirling around an axis of the particulate filter is formed in the chamber .

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