JP2006242011A - Exhaust emission control device and exhaust gas purifying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device and an exhaust gas purifying method for efficiently purifying exhaust gas exhausted from an internal combustion engine such as a diesel engine. <P>SOLUTION: The exhaust emission control device disposed in an exhaust passage of an internal combustion engine and provided with an exhaust purifying member including a catalyst means, is provided with a λ control gas supply means for controlling the air-fuel ratio of at least exhaust gas flowing into the exhaust purifying member, and a passage for supplying λ control gas injected from an injection port of the exhaust purifying member in the exhaust passage, from a supply port disposed upstream of the exhaust purifying member in the exhaust passage. Further, a distance between the injection port and the supply port is adjustable. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust purification device and an exhaust gas purification method in an internal combustion engine. In particular, the present invention relates to an exhaust gas purification apparatus and an exhaust gas purification method capable of efficiently purifying exhaust gas by containing a predetermined amount of carbon monoxide in exhaust gas flowing into an exhaust purification member.

In conventional internal combustion engines such as diesel engines, diesel particulate filters (DPF) and NO _x storage catalysts (LNT) are used to remove chemical substances such as particulate matter (PM) and NO _x in the exhaust gas. Exhaust gas purification members represented by In such an exhaust purifying device, thereby capturing PM and NO _X, etc. in the exhaust gas, or by burning the deposited PM, and or by oxidation-reduction reaction of NO _X, etc., are performed to purify the exhaust gas .
In the exhaust purification apparatus provided with such an exhaust purifying member, the upstream side of the exhaust purifying member, by placing the catalyst means such as oxidation catalyst (DOC) and NO _X reduction catalyst (NSC), collected in the exhaust gas purifying device The exhaust gas purification efficiency is improved by efficiently burning or reducing PM or the like. That is, by providing the DOC and NSC, the temperature of the exhaust gas flowing into the exhaust purification member disposed on the downstream side is raised, and the PM or the like collected by the exhaust purification member is efficiently burned. , NO _{x and} other reduction reactions can be promoted.
However, even when having such a DOC or NSC, when the temperature of the exhaust gas is less than DOC and NSC activity temperature is to efficiently remove PM and NO _X, etc. from the exhaust gas There was a problem that I could not.

Therefore, an exhaust gas purifying device that improves the regeneration efficiency of the DPF by forcibly raising the temperature of the exhaust gas flowing into the catalyst means and activating the catalyst means quickly at low temperature start etc. It has been proposed (see, for example, Patent Document 1).
More specifically, as shown in FIG. 7, when the internal combustion engine starts operation, the fuel supply instructing unit of the controller starts supplying fuel by the electromagnetic pump 351, and the combustion instructing unit of the controller includes the air supply unit and the combustion The burner device 305 starts combustion and supplies combustion gas to the heat exchanger 304. The exhaust gas flowing in from the exhaust gas inlet 311 is heated to a temperature higher than the activation temperature of the oxidation catalyst 303 by the heat exchanger 304, reaches the oxidation catalyst 303, and is an exhaust gas purification device in which the DPF 302 is regenerated.

In addition, as another exhaust purification device, there is a black smoke (PM) removal device that rapidly raises the temperature of the exhaust gas by passing the exhaust gas twice through the catalyst means and improves the regeneration efficiency of the DPF. It has been proposed (see, for example, Patent Document 2).
More specifically, as shown in FIG. 8, in the black smoke (PM) removal device 400 provided with the catalytic combustor 417 on the upstream side of the DPF 406, the low-temperature start of the oxidation catalyst of the catalytic combustor 417 is accelerated, and This is an exhaust gas black smoke removal device 400 with improved durability. According to the black smoke removing device 400, exhaust gas discharged from the engine passes through the catalytic combustor 417, and further passes through the DPF 406, thereby depositing black smoke contained in the exhaust gas on the DPF 406. On the other hand, in the exhaust gas black smoke removal device 400 that burns and removes the black smoke collected by the DPF 406 by the action of the oxidation catalyst of the catalyst combustor 417, the catalyst combustor 417 includes two or more exhaust gases flowing in different directions. Partitioned into sections 417a and 417b, and a heat-exchangeable partition wall is interposed between these sections.
JP 2003-328728 A (Claims Fig. 1) Japanese Patent Laid-Open No. 9-125932 (Claims Fig. 1)

However, the exhaust gas purification device described in Patent Literature 1 and the black smoke removal device described in Patent Literature 2 raise the temperature of the exhaust gas and use the amount of heat to activate and activate the catalyst means. In particular, there has been a problem that it still takes time to reach the activation temperature under low temperature conditions such as at the time of starting.
For this purpose, incomplete combustion gas is injected into the catalyst means using a burner having a specific structure, and carbon monoxide (CO) and raw gas (HC) contained in the incomplete combustion gas are exothermed. There is a method in which the catalyst means is efficiently heated and activated by directly supplying it as an agent or a reducing agent.
However, if the temperature of the incomplete combustion gas injected from the burner collides with and mixes with the exhaust gas of the internal combustion engine in a state where the temperature is higher than the self-ignition temperature of CO, oxygen (O ₂ ) and CO in the exhaust gas are mixed. In some cases, carbon dioxide (CO ₂ ) was generated by the reaction. Therefore, there is a problem that CO cannot be sufficiently supplied to the catalyst means such as DOC and NSC, and the exhaust gas purification efficiency is lowered.

Accordingly, the inventors of the present invention have intensively studied the above problems, and as a result, provided with the predetermined λ control gas supply means, and the injection port of the λ control gas supply means and the λ control gas in the exhaust passage. The present inventors have found that the temperature of the λ control gas can be easily controlled independently of the exhaust gas temperature by making the distance between the supply port variable and the present invention has been completed.
That is, an object of the present invention is to supply an exhaust gas containing a predetermined amount or more of CO to catalyst means such as DOC and NSC, and to perform exhaust gas purification efficiently and It is to provide a method for purifying exhaust gas.

  According to the present invention, there is provided an exhaust purification device that is disposed in an exhaust passage of an internal combustion engine and includes an exhaust purification member that includes catalyst means for controlling at least an air-fuel ratio of exhaust gas flowing into the exhaust purification member. Λ control gas supply means, and a flow path for supplying the λ control gas injected from the injection port of the λ control gas supply means from the supply port disposed upstream of the exhaust purification member in the exhaust passage And an exhaust purification device characterized in that the distance between the injection port and the supply port is variable, and the above-described problems can be solved.

  Further, in configuring the exhaust emission control device of the present invention, it is preferable that the flow path is made of a telescopic pipe.

  Further, in configuring the exhaust purification apparatus of the present invention, the λ control gas supply means can be moved forward and backward with respect to the supply port in the flow path, so that it is between the injection port and the supply port. It is preferable to make the distance variable.

  Further, in configuring the exhaust emission control device of the present invention, the λ control gas supply means includes an injector for supplying fuel, a first air introduction pipe for mixing air with the fuel, and the supplied fuel A fuel evaporation device for heating and evaporating the fuel, an orifice for diffusing and injecting the vaporized fuel, a second air introduction pipe for taking in air for assisting fuel combustion, and igniting the injected fuel And a fuel ignition device for producing a combustion gas.

  In configuring the exhaust emission control device of the present invention, it is preferable that a lambda sensor for measuring the air-fuel ratio of the exhaust gas is provided between the λ control gas supply port and the exhaust emission purification member.

  Another aspect of the present invention is an exhaust gas regeneration method for purifying exhaust gas exhausted from an internal combustion engine using an exhaust purification member including catalyst means, wherein the λ control gas supply means By generating the control gas, and changing the distance between the injection port of the λ control gas supply means and the supply port arranged on the upstream side of the exhaust purification member in the exhaust passage, The exhaust gas purifying method is characterized in that after adjusting the temperature, the exhaust gas is mixed into the exhaust gas and allowed to flow into the exhaust purification member.

According to the exhaust emission control device of the present invention, by changing the distance between the injection port of the λ control gas supply means and the supply port in the exhaust passage, the λ control can be performed independently of the exhaust gas temperature. The temperature of the working gas can be easily cooled to below the temperature at which CO is self-ignited. Therefore, the exhaust gas flowing into the catalyst unit such as an oxidation catalyst (DOC) and NO _X reduction catalyst (NSC), comprising carbon monoxide (CO) is easy to be included more than a predetermined amount.
Therefore, DOC and NSC can be efficiently heated and activated, PM and the like collected by the exhaust purification member such as DPF can be combusted, and exhaust gas purification efficiency can be improved.

  Further, in the exhaust gas purification apparatus of the present invention, since the flow path has a predetermined structure, the flow path can be reliably and easily set to a desired length with a relatively simple configuration. The distance between the port and the supply port in the exhaust passage can be accurately changed. Therefore, the temperature of the λ control gas can be accurately controlled independently of the temperature of the exhaust gas.

  Further, in the exhaust purification apparatus of the present invention, the λ control gas supply means is configured to be capable of moving forward and backward in the flow path, so that the λ control gas supply means can The distance between the supply port in the exhaust passage can be easily changed. Therefore, the temperature of the λ control gas can be accurately controlled independently of the temperature of the exhaust gas.

  Further, in the exhaust purification apparatus of the present invention, by using the λ control gas supply means having a predetermined structure, CO and HC can be efficiently supplied to the DOC and NSC with a small and simple configuration. Therefore, the catalyst means such as DOC and NSC can be effectively heated and activated.

  In the exhaust purification apparatus of the present invention, a lambda sensor (oxygen sensor) for measuring the air-fuel ratio in the exhaust gas flowing into the exhaust purification member is provided at a predetermined position, so that the lambda value of the exhaust gas is within a predetermined range. Thus, the set air-fuel ratio in the λ control gas can be controlled. Therefore, it is possible to efficiently supply the λ control gas in which the lambda value is controlled in accordance with conditions such as the operating state of the internal combustion engine and the temperature of the exhaust gas.

  In addition, according to the exhaust gas purification method of the present invention, the λ control gas, which is controlled to a predetermined temperature independently of the exhaust gas, is mixed with the exhaust gas, so that the catalyst means such as DOC and NSC can be used. The exhaust gas can flow into the catalyst means with a predetermined amount of CO or HC included. Therefore, the catalyst means can be efficiently heated and activated, and PM or the like collected by the exhaust purification member such as DPF can be burned, so that exhaust gas can be purified efficiently.

Embodiments of the present invention are an exhaust purification device that is provided in an exhaust passage of an internal combustion engine and includes an exhaust purification member for purifying exhaust gas, and an exhaust gas purification method using the exhaust purification device.
Hereinafter, the exhaust gas purification apparatus and the exhaust gas purification method in the internal combustion engine according to the present embodiment will be specifically described with reference to the drawings as appropriate. However, this embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention.

1. Exhaust Purification Device (1) Basic Configuration As shown in FIG. 1, the exhaust purification device 10 of this embodiment includes an exhaust purification member 13 that is disposed in the exhaust passage 19 of the internal combustion engine 51 and includes the catalyst means 11. An exhaust purification apparatus 10 for λ control gas supply means for controlling at least an air-fuel ratio of exhaust gas flowing into the exhaust purification member, and for λ control injected from an injection port of the λ control gas supply means And a flow path for supplying gas from a supply port disposed upstream of the exhaust purification member in the exhaust passage, wherein the distance L between the injection port and the supply port is variable. This is the purification device 10.
That is, according to the exhaust gas purification apparatus 10, by providing the λ control gas supply means 17 for supplying the λ control gas, carbon monoxide (CO) and raw gas (HC) can be easily contained in the exhaust gas. Can be included. Further, by making the distance L between the injection port of the λ control gas supply means and the supply port in the exhaust passage variable, the temperature of the λ control gas can be controlled independently of the exhaust gas. Therefore, the exhaust gas can be caused to flow into the catalyst means 11 while maintaining the amounts of CO and HC. Therefore, it is possible to efficiently remove PM, NO _{x and the} like collected by the exhaust purification member 13 such as DPF while efficiently raising and activating the catalyst means 11.

More specifically, by including CO or HC in the exhaust gas flowing into the exhaust gas purification member 13 including the catalyst means 11, the CO acts as a heat generating agent or a reducing agent for the catalyst means 11, Since the temperature can be raised and activated, PM, NO _{x and the} like in the exhaust gas can be efficiently purified. Therefore, it is effective to increase the amount of CO and HC flowing into the catalyst unit 11 by supplying the λ control gas containing a large amount of CO and HC from the λ control gas supply unit 17. However, when the temperature of the λ control gas is equal to or higher than the self-ignition temperature of CO and mixed with or collides with the exhaust gas, CO in the λ control gas reacts with O ₂ in the exhaust gas. Thus, carbon dioxide (CO ₂ ) is generated, and the amount of CO flowing into the catalyst means 11 is reduced. Therefore, by reducing the λ control gas to below the self-ignition temperature of CO and mixing it with the exhaust gas, it is possible to prevent a decrease in the amount of CO and the amount of heat contained in the exhaust gas flowing into the exhaust purification member 13 respectively. it can.
The exhaust gas purification method by the exhaust gas purification apparatus 10 of the present invention will be described in detail later.

(2) Internal combustion engine As the internal combustion engine 51 that exhausts exhaust gas, a diesel engine or a gasoline engine is typical, but not only the exhaust purification member is essential but also the regeneration of the diesel engine is the target. It is suitable to do.
1 is a means for detecting the operating state of the internal combustion engine 51, that is, the rotational speed of the internal combustion engine 51, the exhaust gas temperature, and the like, and based on the detection result, It is preferable that the air-fuel ratio in the λ control gas injected from the λ control gas supply means 17 described later is controlled.

(3) Exhaust passage The exhaust passage 19 is connected to the exhaust port of the internal combustion engine, and the catalyst means 11 and the exhaust purification member 13 are provided in the middle of the exhaust passage 19. The cross-sectional shape of the exhaust passage 19 is not particularly limited as long as it is a circular, elliptical, or prismatic exhaust passage 19.
However, in order to make it easy to attach the predetermined λ control gas supply means 17 independently of the internal combustion engine, it is preferable to provide a bent portion 28 in the middle of the exhaust passage 19 as illustrated in FIG. Further, it is preferable that the λ control gas supply means 17 can be connected to the bent portion 28 via the supply port 29.

(4) Exhaust purification member and catalyst means As the exhaust purification member 13 including the catalyst means, a diesel particulate filter (DPF) is typical. Such a DPF can be made of a known material. For example, the DPF is a filter having a honeycomb structure made of a ceramic material, which collects and purifies PM and other fine particles in the exhaust gas. Further, according DPF is may be a filter alone, for example, it can also be assumed that the catalyst and NO _X adsorbent is coated.
However, the exhaust gas purifying apparatus of the present invention, the upstream side of the DPF 13, includes catalyst means 11 such as an oxidation catalyst (DOC) and NO _X reduction catalyst (NSC). Therefore, CO or the like contained in the exhaust gas flowing into the catalyst means 11 becomes a heat generating agent or a reducing agent, and the catalyst means 11 is heated and activated, so that NO _x is efficiently reduced and removed. In addition, the temperature of the exhaust gas flowing into the downstream DPF or the like can be raised to efficiently burn the collected PM or the like.

For example, when the DOC is provided, the temperature of the DOC is raised to the activation temperature or higher by heat from the combustion gas from the temperature raising burner. In addition, CO and HC discharged from the λ control gas supply means described later undergo an oxidation reaction with O ₂ in the exhaust gas at the DOC that is higher than the activation temperature, and the oxidation heat further increases the temperature of the DOC. Thus, the exhaust gas whose temperature has been raised can be caused to flow into the DPF.
On the other hand, when the NSC is provided, the temperature of the NSC is raised by the heat of the combustion gas from the temperature raising burner. Further, in NSC became more activation temperature, CO and HC discharged from the λ control gas supply means will be described later, acts as a reducing agent of the NO _X or the like which is collected in the NSC, NO _X is reduced to nitrogen CO and HC are oxidized. The temperature of the NSC can be further increased by the reaction heat at that time, and the exhaust gas whose temperature has been increased can flow into the DPF.
Therefore, by providing catalyst means such as DOC or NSC upstream of the DPF, the exhaust gas whose temperature has been raised by the heat of the combustion gas from the temperature raising burner is the CO gas discharged from the λ control gas supply means. By efficient catalytic combustion with HC and HC, the exhaust gas can be further heated to purify the exhaust gas by burning PM or the like collected in the DPF.

(5) λ control gas supply means and flow path Further, the λ control gas supply means 17 generates λ control gas containing a large amount of CO and HC, and in the exhaust gas passing through the exhaust passage 19. It is a means for making it supply. The λ control gas injected from the λ control gas supply means 17 is supplied into the exhaust passage 19 through a supply port 29 connected to the exhaust passage 19 on the upstream side of the exhaust purification member 13. Therefore, since a predetermined amount or more of CO or HC can be allowed to flow into the catalyst means 11 in the exhaust purification member, the catalyst means 11 can be heated and activated to efficiently purify the exhaust gas.

As the λ control gas supply means 17, for example, as shown in FIG. 2, an injector 61 for supplying high-pressure fuel, a first air introduction pipe 63 for mixing air with the high-pressure fuel, and a supply A fuel evaporation device 65 for heating and evaporating the generated fuel, an orifice 67 for diffusing and evaporating the evaporated and vaporized fuel, and a second air introduction pipe for taking in air for assisting combustion of the fuel 69, a burner 60 including a fuel ignition device 71 for igniting the fuel to form combustion gas, and an oxidation catalyst 73 is preferable.
The reason for this is that, with this configuration, for example, the burner can be downsized and the amount of CO contained in the injected combustion gas can be easily controlled as compared with a premixed type burner. This is because it can be done. More specifically, the fuel injected by the diffusion type orifice 67 can be easily incompletely burned by adjusting the amount of air taken in from the first air introduction pipe 63 and the second air introduction pipe 69. The incomplete combustion gas containing the raw gas (HC) further passes through the oxidation catalyst 73, whereby the HC can be efficiently incompletely burned to generate more CO.
Further, in the case of such a burner 60, for example, based on the air-fuel ratio of exhaust gas measured by a lambda sensor 23 described later, the set air-fuel ratio is adjusted by the λ control gas supply means 17 independently of the internal combustion engine 51. A predetermined amount of CO and a predetermined amount of heat can be supplied to the catalyst means 11 in the exhaust purification member from the middle of the exhaust passage 19 in a high temperature state. Therefore, the exhaust gas can be efficiently purified regardless of the operating state of the internal combustion engine 51.

The exhaust purification apparatus 10 of the present invention supplies the λ control gas injected from the λ control gas supply means 17 from the supply port 29 disposed on the upstream side of the exhaust purification member 13 in the exhaust passage 19. A flow path 27 is provided. In the flow path 27, the distance L between the injection port 17a of the λ control gas supply means 17 and the supply port 29 in the exhaust passage 19 is variable.
That is, by making the distance L variable, the amount of heat released when the relatively high temperature λ control gas injected from the λ control gas supply means 17 passes through the flow path is different. Can be made. Therefore, the temperature of the λ control gas at the time when the λ control gas is mixed with the exhaust gas is determined so that the oxidation of carbon monoxide (CO) is independent of the temperature of the exhaust gas and the operating state of the internal combustion engine 51. It can be easily controlled to be below the promoted temperature. In addition, since it is possible to prevent the temperature from being lowered more than necessary, it is possible to secure a predetermined amount or more of CO and heat in the exhaust gas flowing into the catalyst means 11.

  More specifically, when the temperature of the λ control gas in the λ control gas supply port 29 in the exhaust passage 19 exceeds the temperature at which CO oxidation is promoted, the supply port 29, By increasing the distance L between the λ control gas supply means 17 and the injection port 17a, the temperature of the λ control gas at the time of mixing with the exhaust gas can be lowered. On the other hand, when the temperature of the λ control gas at the λ control gas supply port 29 in the exhaust passage 19 is extremely low, the distance between the supply port 29 and the injection port 17 a of the λ control gas supply means 17. By shortening L, the temperature of the λ control gas at the time of mixing with the exhaust gas can be maintained at a predetermined temperature or higher.

As a means for making the distance L between the injection port and the supply port variable, for example, as shown in FIG. 3A, a part of the flow path 27 of the λ control gas is constituted by a telescopic pipe 26. be able to. In such a configuration, the flow path can be reliably and easily set to a desired length with a relatively simple configuration. Therefore, in the injection port 17 a of the λ control gas supply means 17 and the exhaust passage 19. The distance L between the supply port 29 can be accurately changed.
Further, as another example of means for making the distance L between the injection port and the supply port variable, as shown in FIG. The feed port 29 can be configured to move forward and backward. In such a configuration, the distance L between the injection port 17a of the λ control gas supply means 17 and the supply port 29 in the exhaust passage 19 can be easily changed without changing the outer shape of the flow path 27. Can do.

Further, the distance L between the injection port 17a of the λ control gas supply means 17 and the supply port 29 in the exhaust passage 19 is measured at the λ control gas supply port 29 in the exhaust passage 19. It is preferable to be able to control based on the gas temperature.
The reason for this is that even when the temperature of the λ control gas changes due to various environmental conditions, the temperature at the supply port in the exhaust passage can be successively controlled with high accuracy in accordance with the temperature. Because.

(6) Lambda sensor A lambda sensor 23 for measuring the air-fuel ratio of the exhaust gas flowing into the catalyst means 11 is provided between the supply port 29 of the λ control gas supply means 17 and the catalyst means 11. It is preferable.
This is because by providing the lambda sensor 23, the set air-fuel ratio in the λ-control gas supply means 17 can be adjusted based on the air-fuel ratio in the exhaust gas mixed with the λ-control gas. is there. Therefore, the air-fuel ratio of the exhaust gas flowing into the exhaust purification member 13 including the catalyst means 11 can be controlled to the state where the catalyst means 11 is most activated in accordance with the operating state of the internal combustion engine and the exhaust gas temperature. That is, when the temperature of the exhaust gas from the internal combustion engine is relatively high or low, or when the content of CO or HC contained in the exhaust gas is large, the predetermined burner described above is taken into consideration Thus, the exhaust gas mixed with the λ control gas can be supplied to the catalyst means 11 after adjusting the amount of CO and HC and the amount of heat. Therefore, the catalyst means 11 can be efficiently heated and activated to further improve the exhaust gas purification efficiency.

(7) Others Further, as shown in FIGS. 4A to 4B, the exhaust emission control device of the present invention includes heat exchange means 15 for exchanging heat between the exhaust gas and the λ control gas. It is preferable.
The reason for this is that the temperature of the exhaust gas can be raised by utilizing the amount of heat released when the temperature of the λ control gas is cooled to below the self-ignition temperature of CO. Therefore, when the exhaust gas and the λ control gas collide and mix, it prevents the CO in the λ control gas and the O ₂ in the exhaust gas from reacting to generate carbon dioxide (CO ₂ ). However, the amount of heat supplied to the exhaust purification member including the catalyst means can be maintained, and the temperature rise and activation of the catalyst means 11 can be effectively performed.
Such heat exchanging means is not particularly limited, and any heat exchanging means that can exchange heat between the exhaust gas and the λ control gas can be preferably used. For example, as shown in FIGS. 4 (a) and 5 (a), a tubular member 15a is used which is disposed at the supply port 29 of the λ control gas supply means 17 and has a plurality of irregularities (fin portions) 16 on the surface. can do. This is because the tubular member 15a can efficiently exchange heat between the exhaust gas and the λ control gas with a relatively simple configuration. Further, as shown in FIGS. 4B and 5B, the exhaust passage 19 and the λ control gas flow passage 27 arranged in a direction orthogonal to the exhaust passage 19 are arranged so as to contact each other. It is also possible to provide the heat exchange unit 15b. With such a heat exchanging portion 15b, it is possible to efficiently exchange heat by changing the arrangement design of the respective flow passages 19 and 27, and compared with the case where the tubular member 15a is used, λ control is achieved. The degree of freedom in the layout design of the gas supply port 29 can be increased.

Further, as shown in FIG. 6, the exhaust purification device 10 of the present invention is connected to the exhaust passage 19 via a supply port 30 connected to the upstream side of the exhaust purification member 13, and the like is a flame that burns fuel. Therefore, it is preferable to provide a temperature raising burner 18 for raising the temperature of the exhaust gas flowing through the exhaust passage 19.
This is because the temperature of the exhaust gas can be sufficiently raised before the exhaust gas and the λ control gas are mixed, and a large amount of heat can be contained in the exhaust gas. Moreover, it is because heating efficiency can be remarkably improved compared with the case where the temperature of exhaust gas is raised by post injection or the like.
Such a temperature raising burner is not particularly limited, and a commonly used combustion burner or the like can be suitably used. However, it is preferable that the engine fuel is used as it is and combusted in consideration of the fuel use efficiency and the arrangement of the fuel tank.

2. Exhaust Gas Purification Method Next, an exhaust gas purification method implemented using the above-described exhaust purification device 10 of the present invention will be described in detail.
Such an exhaust gas purification method is an exhaust gas purification method for purifying exhaust gas discharged from an internal combustion engine 51 such as a diesel engine using an exhaust purification member 13 including a catalyst means 11, which is a λ control gas. By generating the λ control gas by the supply means and changing the distance L between the injection port of the λ control gas supply means and the supply port arranged on the upstream side of the exhaust purification member in the exhaust passage. After adjusting the temperature of the λ control gas, it is mixed in the exhaust gas and flows into the exhaust purification member.

First, the λ control gas is generated by the λ control gas supply means 17.
In the exhaust purification apparatus described above, an incomplete combustion gas containing a large amount of CO as a λ control gas is generated using a predetermined burner 60 as shown in FIG. With such a burner 60, as described above, the fuel can be efficiently incompletely combusted, so that a large amount of CO can be efficiently contained in the incomplete combustion gas. At this time, the temperature of the incomplete combustion gas (λ control gas) injected from the burner 60 is in a relatively high temperature state and is equal to or higher than the temperature (about 600 ° C.) at which CO oxidation is promoted.

Next, the generated λ control gas is supplied from the supply port in the exhaust passage 19 via the flow path 27. At this time, when the λ control gas and the exhaust gas are mixed, the amount of CO contained in the λ control gas is oxidized to generate CO ₂ , and the amount of CO in the exhaust gas decreases. In order to prevent this, the temperature of the λ control gas at the supply port 29 of the exhaust passage 19 is measured, and the distance L between the injection port 17 a of the λ control gas supply means 17 and the supply port 29 is controlled. That is, as already described in detail, when the measured temperature at the supply port 29 is higher than the temperature at which the oxidation of CO is promoted, the distance L between the injection port 17a and the supply port 29 is changed to be large, Reduce the temperature of the λ control gas. On the other hand, when the measured temperature at the supply port 29 is extremely low, the distance L between the injection port 17a and the supply port 29 is changed so as to decrease the temperature of the λ control gas. By controlling in this way, the amount of CO contained in the λ control gas can be secured to a predetermined amount or more without excessively reducing the temperature of the λ control gas.

At this time, in the case where the exhaust purification device is provided with the heat exchange means 15 shown in FIGS. 4A to 4B, before the λ control gas and the exhaust gas collide and mix, λ control gas is subjected to heat exchange. That is, the temperature of the exhaust gas is raised using the amount of heat released when the temperature of the λ control gas is lowered.
This is because a predetermined amount of heat can be included in the exhaust gas without reducing the enthalpy of the exhaust gas and the overall λ control gas as much as possible.

Further, when the exhaust gas purification apparatus includes the temperature raising burner 18 shown in FIG. 6, the exhaust gas discharged from the internal combustion engine 51 and flowing through the exhaust passage 19 is raised using the temperature raising burner 18. Warm up. For example, when the engine is in a normal operation state, the temperature of the exhaust gas is about 150 to 300 ° C., but the temperature of the exhaust gas is raised to about 300 to 400 ° C. by the temperature raising burner 18. Thereby, compared with the case where post injection is performed, the temperature of exhaust gas can be efficiently raised while suppressing deterioration of fuel consumption.
At this time, it is preferable to burn enough fuel to burn the fuel using O ₂ contained in the exhaust gas. This is because HC as a reducing agent or the like can be supplied from the λ control gas supply means 17, so that the fuel consumption in the temperature raising burner 18 can be minimized.

Next, the λ control gas is mixed with the exhaust gas and flows into the exhaust purification member 13 including the catalyst means 11.
At this time, as described above, since it can be mixed with the exhaust gas without reducing the amount of CO contained in the λ control gas, it flows into the catalyst means 11 while containing a predetermined amount of CO. Can be made. Further, when the lambda sensor 23 is provided between the λ control gas supply port 29 and the catalyst means 11, the lambda value (air-fuel ratio) of the exhaust gas measured by the lambda sensor 23 is taken into consideration. By controlling the air-fuel ratio of the λ control gas, the air-fuel ratio of the exhaust gas is efficiently increased and activated so that the catalyst means 11 can be efficiently heated and activated while taking into consideration the operating state of the internal combustion engine and the temperature of the exhaust gas. Can be controlled.

For example, when a DOC is provided as a catalyst means, when the exhaust gas containing a predetermined amount of CO or heat passes through the DOC, the CO acts as a heat generating agent for the DOC, and the DOC is efficiently heated and activated. And the temperature of the exhaust gas can be further raised. Therefore, since PM collected by the DPF disposed on the downstream side of the DOC can be burned, the exhaust gas can be purified efficiently.
On the other hand, when armed with the NSC as a catalyst unit, by exhaust gas containing a predetermined amount of CO and heat passes through the NSC, CO is a reducing agent, NO _X adsorbed in the NSC is reduced to nitrogen CO is oxidized. Then, the NSC is efficiently heated and activated by the reaction heat at that time. Therefore, since the temperature of the exhaust gas passing therethrough can be further raised, the PM trapped in the DPF disposed downstream of the NSC is efficiently burned to efficiently purify the exhaust gas. be able to.

  As described above, according to the exhaust gas purification method of the present invention, the catalyst in the exhaust purification member can be controlled by independently controlling the temperature of the λ control gas even when the internal combustion engine is in any operating state. A predetermined amount of CO can be included in the exhaust gas flowing into the means. Therefore, the exhaust gas can be efficiently purified by efficiently raising the temperature and activating the catalyst means in the exhaust purification member.

It is a figure which shows the exhaust gas purification apparatus of this invention. It is a figure which shows the burner as (lambda) control gas supply means. (A)-(b) is a figure provided in order to demonstrate the means which makes variable the distance of the injection port of (lambda) control gas supply means, and the supply port in an exhaust passage, respectively. (A)-(b) is a figure which shows the exhaust gas purification apparatus provided with the heat exchange means, respectively. (A) is a figure which shows the tubular member as a heat exchange means, (b) is a figure which shows the heat exchange part as a heat exchange means. It is a figure provided in order to demonstrate the exhaust gas purification apparatus provided with the burner for temperature rising. It is a figure provided in order to demonstrate the conventional purification apparatus of exhaust gas. It is a figure provided in order to demonstrate the conventional black smoke removal apparatus.

Explanation of symbols

10: Exhaust purification device 11: Catalyst means 13: Exhaust purification member (DPF)
15: Heat exchange means (heat exchange part)
17: λ control gas supply means 17a: injection port 18: temperature rising burner 19: exhaust passage 23: lambda sensor 26: flow path length variable means (telescopic pipe)
27: λ control gas flow path 28: bent portion 29: supply port 51: internal combustion engine 60: burner (λ control gas supply means)

Claims (6)

An exhaust purification device that is disposed in an exhaust passage of an internal combustion engine and includes an exhaust purification member including catalyst means,
Λ control gas supply means for controlling at least the air-fuel ratio of the exhaust gas flowing into the exhaust purification member;
A flow path for supplying the λ control gas injected from the injection port of the λ control gas supply means from a supply port arranged on the upstream side of the exhaust purification member in the exhaust passage,
An exhaust emission control device characterized in that a distance between the injection port and the supply port is variable.   The exhaust purification device according to claim 1, wherein the flow path is formed of a telescopic pipe.   The distance between the injection port and the supply port is variable by enabling the λ control gas supply means to move forward and backward with respect to the supply port in the flow path. The exhaust emission control device according to claim 1.   The λ control gas supply means includes an injector for supplying fuel, a first air introduction pipe for mixing air with the fuel, and fuel evaporation for heating and evaporating the supplied fuel. A device, an orifice for diffusing and injecting the vaporized fuel, a second air introduction pipe for taking in air for assisting combustion of the fuel, and for igniting the injected fuel into combustion gas The exhaust emission control device according to any one of claims 1 to 3, further comprising:   The lambda sensor for measuring the air fuel ratio of the said exhaust gas is provided between the supply port of the said (lambda) control gas, and the said exhaust purification member, The any one of Claims 1-4 characterized by the above-mentioned. 2. An exhaust gas purification apparatus for an internal combustion engine according to 1. An exhaust gas regeneration method for purifying exhaust gas discharged from an internal combustion engine using an exhaust purification member including catalyst means,
The λ control gas supply means generates λ control gas,
After adjusting the temperature of the λ control gas by changing the distance between the injection port of the λ control gas supply means and the supply port arranged upstream of the exhaust purification member in the exhaust passage A method for purifying exhaust gas, wherein the exhaust gas is mixed in the exhaust gas and allowed to flow into the exhaust purification member.

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