JP4162239B2 - Exhaust purification member regeneration device and regeneration method - Google Patents

Description

  The present invention relates to a regeneration device for an exhaust purification member in an internal combustion engine, and particularly relates to a regeneration device for an exhaust purification member that is arranged independently of the internal combustion engine and can efficiently regenerate the exhaust purification member in a diesel engine.

Conventional internal combustion engines such as diesel engines are represented by diesel particulate filters (DPF) and NOx storage catalysts (LNT) in order to remove diesel particulates (PM) and other chemical substances in the exhaust gas. An exhaust purification member is provided.
However, when exhaust gas treatment is performed by such an exhaust purification member, the DPF has a problem that clogging occurs due to PM or the like with the passage of time. Further, even in LNT, when the temperature of the catalyst is lower than the activation temperature or the reducing agent is insufficient, there is a problem that NOx cannot be sufficiently reduced and clogging occurs.

With respect to such a problem, with respect to the DPF, it is necessary to remove the collected PM and the like from the filter every predetermined time and regenerate the filter. As such a DPF regeneration method, heating regeneration by an electric heater, heating regeneration by a combustion burner, and the like are typical.
However, heating regeneration using an electric heater has a problem that a predetermined supply power must be ensured, and there is a problem that heat dissipation is relatively large and is not suitable for a filter having a high thermal conductivity. . On the other hand, the heat regeneration by the combustion burner has advantages that the energy conversion efficiency is relatively high, a predetermined amount of heat can be given, and the filter or the like can be regenerated in a relatively short time. More specifically, as shown in FIG. 8 (b), a bypass 220 is provided in an exhaust pipe 224 of a diesel engine (not shown), and an aspirator burner 200 shown in FIG. 8 (a) is attached thereto. A heating regeneration method using the heating regeneration apparatus 250 has been proposed (see, for example, Patent Document 1).
As another DPF regeneration method, a heat regeneration method using a catalyst burner is disclosed. More specifically, as shown in FIGS. 9A and 9B, a catalytic burner 302 is attached in series between a diesel engine (not shown) and a particle filter 306, and the diesel engine And a heating regeneration method using a heating regeneration device 300, 300 ′ in which a fuel metering device 304, a heater 308, or a nitrogen oxide-oxidation unit 305 are further arranged between the catalytic burner 302 ( For example, see Patent Document 2).

On the other hand, for LNT, it is necessary to raise the temperature of the catalyst to the activation temperature or supply a reducing agent. As such LNT regeneration methods, heat regeneration by a combustion burner, regeneration by injection of a reducing agent, and the like have been proposed. More specifically, as a heating regeneration method using a combustion burner, as shown in FIG. 10, in order to easily control the air-fuel ratio and reduce HC emissions, combustion air is supplied from the outside, There has been proposed a heating regeneration method using a burner 100 having a structure in which fuel is completely burned using two ceramic heaters 104 and 116 (see, for example, Patent Document 3).
Further, as a regeneration method by injection of a reducing agent, as shown in FIG. 11, a NOx storage catalyst 410 is disposed downstream of an exhaust pipe 406 of an internal combustion engine (not shown). A reducing agent supply nozzle 402 for spraying and supplying a reducing agent 404 such as fuel is provided on substantially the entire front surface, and a cooling pipe 401 for cooling the reducing agent supply nozzle 402 is provided. There has been proposed an exhaust purification device 400 in which a supply nozzle 402 is provided at a position where a traveling wind generated by traveling of a vehicle hits (see, for example, Patent Document 4).
JP 2004-3400 A (Claims, FIGS. 1-2) JP-T-2003-533626 (Claims, FIGS. 1-2) Utility Model Registration No. 2545072 (Scope of Claim for Utility Model Registration, FIGS. 1-2) JP 2003-83056 A (Claims, FIG. 1)

  However, according to the DPF regeneration method using the combustion burner and the catalyst burner disclosed in Patent Documents 1 and 2, respectively, when the DPF is heated to a predetermined temperature in order to oxidize (combust) PM or the like, a diesel engine or the like There was a problem of being directly affected by the flow rate and temperature of the exhaust gas discharged from the plant. Therefore, while considering the operating conditions of diesel engines, etc., the exhaust gas flow rate must be distributed at an appropriate rate and the heating conditions of the burner must be strictly controlled. On the other hand, the DPF regeneration timing, regeneration conditions, etc. There was a problem of being restricted.

In addition, according to the LNT regeneration method disclosed in Patent Document 3, only the fuel is efficiently burnt completely by the burner and only the LNT is heated. as the reducing agent, and the content of carbon monoxide in the combustion gases (CO), the content of unburned fuel gas (HC or fuel unburned components) was adjusted to a value within a predetermined range, the LNT efficiently Reproduction was not considered at all.
Furthermore, in the regeneration method of the NOx occlusion catalyst using the reducing agent supply nozzle disclosed in Patent Document 4, the regeneration of the NOx occlusion catalyst is attempted with a cooled reducing agent, and the LNT is rapidly brought to an activation temperature or higher. For example, it is difficult to heat to 300 ° C. or higher, and it is difficult to efficiently regenerate LNT. Further, as the carbon monoxide (CO) and unburned fuel gas (HC) for supplying to the NOx storage catalyst of a reducing agent of NOx itself, has not been any consideration.

Therefore, the inventors of the present invention have intensively studied the above problems. As a result, a burner provided with an oxidation catalyst for oxidizing the combustion gas is disposed at a predetermined location in the exhaust passage, and the fuel is intentionally burnt incompletely. , and carbon monoxide in the combustion gas (CO), by injecting the combustion gases with an increased content of unburned fuel gas (HC), it found that can play exhaust purifying member effectively, the present invention It has been completed.
That is, an object of the present invention is provided with an oxidation catalyst for oxidizing the combustion gas injected from the burner in the burner connected to the upstream side of the exhaust purification member via the injection outlet communicating with the exhaust passage. by carbon monoxide in the combustion gas (CO), unburned fuel gas (HC), the amount of heat can be easily controlled, irrespective of the such operating conditions such as a diesel engine, a diesel particulate filter (DPF) and NOx An object of the present invention is to provide an exhaust purification member regeneration device capable of efficiently regenerating the storage catalyst (LNT) and the like.

According to the present invention, there is provided a regeneration device for an exhaust purification member that is provided in an exhaust passage of an internal combustion engine and purifies exhaust gas, and includes a predetermined amount of carbon monoxide (CO) and unburned fuel gas (HC). An exhaust purification member regeneration device comprising a burner for injecting combustion gas containing gas and an oxidation catalyst for oxidizing the combustion gas injected from the burner is provided, and the above-described problems can be solved. .

  Further, in configuring the exhaust purification member regeneration device of the present invention, it is preferable that the upstream side of the exhaust purification member is connected via an injection outlet communicating with the exhaust passage.

  In configuring the exhaust purification member regeneration device of the present invention, the burner heats the supplied fuel, 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 evaporating the fuel, 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 igniting the injected fuel A fuel ignition device for producing combustion gas.

In configuring the exhaust purification member regeneration device of the present invention, it is preferable to set the air-fuel ratio in the burner to a value within the range of less than 0.1 to 1.0.
The air-fuel ratio in the burner means the measured value of the air-fuel ratio of the combustion gas injected from the burner or the set value of the air-fuel ratio of the combustion gas injected from the burner, and hereinafter referred to as the set air-fuel ratio There is.

  Further, in configuring the exhaust purification member regeneration device of the present invention, it is preferable that a lambda sensor for measuring the air-fuel ratio in the exhaust gas is provided between the injection outlet and the exhaust purification member.

  In configuring the regeneration device for an exhaust purification member of the present invention, the exhaust purification member preferably includes a particulate filter provided with an NOx storage catalyst or an oxidation catalyst on the upstream side.

Another aspect of the present invention is an exhaust purification member regeneration method for purifying exhaust gas, which is provided in an exhaust passage of an internal combustion engine, and an operating state detecting means for detecting an operating state of the internal combustion engine. A burner which is connected to an upstream side of the exhaust purification member via an injection outlet communicating with the exhaust passage and injects a combustion gas containing a predetermined amount of carbon monoxide (CO) and unburned fuel gas (HC); An oxidation catalyst for oxidizing the combustion gas injected from the burner, and the combustion gas that has passed through the oxidation catalyst is detected from the burner according to the operating state of the internal combustion engine detected by the operating state detecting means. A method for regenerating an exhaust purification member characterized by injecting combustion gas so as to include a certain amount of carbon monoxide (CO) and unburned fuel gas (HC) .

That is, according to the regeneration device for an exhaust purification member of the present invention, the burner and the predetermined oxidation catalyst are provided and connected independently from the internal combustion engine, so that the operation can be performed independently of the internal combustion engine. it is possible to control the set air-fuel ratio of the burner and, from unburned fuel gas contained in the combustion gas, it is possible to efficiently generate carbon monoxide.
Therefore, the amount of heat contained in the combustion gases, unburned fuel gas, it is possible to easily control the amount of carbon monoxide, or efficiently oxidized (burned) adsorbed on PM and the like in a diesel particulate filter or the like, It is possible to efficiently reduce NOx in a NOx storage catalyst or the like.
Therefore, it is possible to efficiently regenerate the filter on which PM or the like is adsorbed, the NOx occlusion catalyst whose temperature is lowered, etc., even when it is carried out periodically, as well as when it is carried out periodically. .

Further, according to the reproducing apparatus of the exhaust purifying member of the present invention, by connecting a predetermined position of the exhaust passage, regardless of the operating state of the internal combustion engine, which is injected from the playback apparatus, a predetermined amount of unburned fuel gas, The combustion gas containing carbon monoxide and heat can be efficiently guided to the exhaust purification member, and can be regenerated more efficiently.

  Further, according to the exhaust purification member regeneration apparatus of the present invention, the burner includes a predetermined injector, a first air introduction pipe, a fuel evaporation apparatus, an orifice, a second air introduction pipe, and a fuel ignition apparatus. And the burner structure can be simplified and miniaturized, and the set air-fuel ratio of the combustion gas can be easily controlled to efficiently regenerate the exhaust purification member.

  According to the exhaust purification member regeneration device of the present invention, the exhaust air purification member can be set regardless of the operation state of the diesel engine or the like by setting the set air-fuel ratio in the burner provided at the predetermined position within a predetermined range. Can be heated to a predetermined temperature to efficiently oxidize PM or the like, or NOx can be efficiently reduced.

In addition, according to the exhaust purification member regeneration device of the present invention, the exhaust gas exhausted into the exhaust purification member is emptied by providing a lambda sensor (oxygen sensor) for measuring the air-fuel ratio in the exhaust gas at a predetermined position. The set air-fuel ratio in the burner can be controlled by measuring the fuel ratio. Accordingly, the content of the content and unburned fuel gas of carbon monoxide in the combustion gases (CO) (HC), can be adjusted independently each precisely, furthermore, the carbon monoxide in the exhaust gas taking into account the content of the content and unburned fuel gas (HC) of (CO), it can also be accurately adjusted for each.

Further, according to the exhaust purification member regeneration device of the present invention, the target exhaust purification member includes a particulate filter provided with a predetermined NOx storage catalyst or an oxidation catalyst on the upstream side, so that combustion is blown from the burner. carbon monoxide in the gas (CO), unburned fuel gas (HC), and a predetermined amount of heat, can be reproduced efficiently from each.

Further, according to the method for regenerating an exhaust purification member of the present invention, the set air-fuel ratio in the burner is set within a predetermined range from a burner disposed at a predetermined position and provided with an oxidation catalyst corresponding to the operating state of the internal combustion engine. is controlled to a value, by injecting the combustion gases, unburnt fuel gas and carbon monoxide, can be effectively utilized as a heating agent or a reducing agent. Therefore, regardless of the operating state of the diesel engine or the like, the exhaust purification member is independently raised to a predetermined temperature, and the PM adsorbed on the diesel particulate filter or the like is efficiently oxidized (burned). In addition, NOx can be efficiently reduced in a NOx storage catalyst or the like.
Therefore, it is possible to efficiently regenerate the filter on which PM or the like is adsorbed, the NOx occlusion catalyst whose temperature is lowered, etc., even when it is carried out periodically, as well as when it is carried out periodically. .

As shown in FIG. 1, an embodiment of the present invention is an exhaust purification member regeneration device 10 provided in an exhaust passage of an internal combustion engine for purifying exhaust gas, which includes a predetermined amount of carbon monoxide (CO). ) And a burner 12 for injecting combustion gas containing unburned fuel gas (HC), and an oxidation catalyst 13 for oxidizing the combustion gas injected from the burner 12. This is a playback device 10.
Hereinafter, the regeneration device and regeneration method for the exhaust purification member in the internal combustion engine according to the present embodiment will be described. FIG. 1 is a diagram provided to explain a specific configuration of the exhaust purification member regeneration device of the present embodiment, and FIGS. 2 and 3 respectively show the exhaust purification member regeneration device as an exhaust gas of an internal combustion engine. It is a figure which shows the state prepared in the channel | path.

1. Basic Configuration The regeneration device for an exhaust purification member of the present embodiment includes a burner 12 and an oxidation catalyst 13 for oxidizing combustion gas injected from the burner 12, as shown in FIG. And That is, by providing the oxidation catalyst 13, (sometimes hereinafter referred to as "fuel gas".) Unburned fuel gas in the combustion gas is burned at a predetermined set air-fuel ratio in the burner 12 was oxidized, efficient This is because carbon monoxide can be produced.
More specifically, since the combustion gas injected from the burner 12 includes a predetermined amount of heat and fuel gas, normally, a part of the fuel gas causes incomplete combustion due to residual heat, and a small amount of monoxide. Carbon is generated. However, in the case of the regenerator 10 of the present embodiment, since the oxidation catalyst 13 is provided on the downstream side of the burner 12, the oxidation catalyst 13 is activated by the amount of heat in the combustion gas, and the fuel in the combustion gas. The gas and a small amount of oxygen cause incomplete combustion by the oxidation catalyst 13 and can efficiently generate carbon monoxide. Therefore, regeneration of exhaust purification members such as diesel particulate filter (DPF) and NOx occlusion catalyst (LNT) using the amount of heat in the combustion gas, carbon monoxide (CO), and remaining fuel gas (HC). Efficiency can be significantly improved.
The effect of the combustion gas injected from the regenerator of the present invention on the regeneration of the exhaust purification member will be described in detail later.

2 and 3, the regenerator 10 is provided in the exhaust passage 20 of the internal combustion engine 51, and is an injection outlet communicating with the exhaust passage 20 on the upstream side of the exhaust purification members 36 and 44. 16 is connected.
That is, when the operation state of the internal combustion engine is idling and the exhaust temperature is relatively low because it is connected via an injection outlet communicating with the exhaust passage of the internal combustion engine independently of the internal combustion engine Even so, in the burner, fuel and air can be mixed at a desired concentration and combusted at a predetermined air-fuel ratio according to the operating state of the internal combustion engine. Alternatively, even if the engine is in a normal operating state and the exhaust temperature is relatively high, it can be similarly burned at a predetermined set air-fuel ratio corresponding to the operating state of the internal combustion engine. Conversely, since the combustion state of the burner is also less likely to affect the operation state of the internal combustion engine, the regeneration of the diesel particulate filter (DPF), NOx storage catalyst (LNT), etc. There is no need to set the operating state of the internal combustion engine to a predetermined state. Therefore, regarding the regeneration of exhaust purification members such as diesel particulate filters and NOx storage catalysts, when the performance of the diesel particulate filter, NOx storage catalyst, etc. has deteriorated, it is regularly determined regardless of the operating state of the internal combustion engine. Of course, the exhaust purification member can be regenerated at any time.

2. Oxidation catalyst The oxidation catalyst 13 for oxidizing the combustion gas injected from the burner 12 is not particularly limited, and a known amount, for example, a material in which platinum is supported on alumina, has a predetermined amount. What added rare earth elements, such as cerium, can be used.
That is, as the degree of influence of carbon monoxide (CO) and fuel gas (HC) on the regeneration of the exhaust purification member, it is generally said that carbon monoxide is superior to fuel gas. By providing the catalyst 13, the fuel gas (HC) contained in the combustion gas injected from the burner 12 can be efficiently incompletely burned and converted to carbon monoxide (CO).

3. As shown in FIG. 1, the burner 12 heats the supplied fuel, an injector 60 for supplying high-pressure fuel, a first air introduction pipe 70 for mixing air with the high-pressure fuel, and the supplied fuel. A fuel evaporation device 81 for evaporating the fuel, an orifice 80 for diffusing and evaporating the evaporated and vaporized fuel, a second air introduction pipe 87 for taking in air for assisting fuel combustion, and ignition of the fuel And a fuel ignition device 84 for producing a combustion gas.
The reason for this is that, with this configuration, for example, the burner 12 can be reduced in size as compared with a premixed type burner, and unburned fuel gas contained in the injected combustion gas This is because the amount of (HC) can be easily controlled. More specifically, by diffusing and injecting the fuel through the diffusion type orifice 80, the fuel in the central portion does not burn because it does not touch the air taken in from the second air introduction pipe 87. Therefore, it can be made to inject in the state contained in combustion gas as fuel gas.

4). Further, as illustrated in FIG. 1, it is preferable that a lambda sensor 24 for measuring an air-fuel ratio in the exhaust gas is provided between the injection outlet 16 communicating with the exhaust passage and the exhaust purification members 36 and 44.
The reason is that by setting the lambda sensor 24 in this way, the set air-fuel ratio in the burner is adjusted based on the air-fuel ratio in the exhaust gas mixed with the combustion gas injected from the burner 12 and passed through the oxidation catalyst 13. This is because it can be done.

When the lambda sensor 24 is arranged as shown in FIG. 1, for example, the set air-fuel ratio in the burner is adjusted independently of the internal combustion engine based on the air-fuel ratio in the exhaust gas measured by the lambda sensor 24. A predetermined amount of carbon monoxide (CO), fuel gas (HC), and a predetermined amount of heat can be supplied to the exhaust purification member from the middle of the exhaust passage 20 in a high temperature state, and the operating state of the internal combustion engine Regardless, the exhaust purification member can be efficiently regenerated.
Further, in accordance with the operating state of the internal combustion engine, a predetermined amount of carbon monoxide, fuel gas , and a predetermined amount of combustion gas are supplied to the exhaust gas purification member by the exhaust gas purification member regeneration device of the present invention. It can also be supplied. That is, when the temperature of the exhaust gas from the internal combustion engine is relatively high or low, or when the content of carbon monoxide or fuel gas contained in the exhaust gas is large, these are taken into consideration. By adjusting the predetermined amount of carbon monoxide, fuel gas, and predetermined amount of heat by the exhaust purification member regeneration device, the combustion gas can be supplied to the exhaust purification member, and the exhaust purification member is regenerated more efficiently. be able to.

5. Internal combustion engine In FIGS. 2 and 3, a diesel engine or a gasoline engine is typically used as the internal combustion engine 51 that discharges exhaust gas indicated by an arrow D, but it is not only necessary to attach an exhaust purification member, It is suitable to target diesel engines whose regeneration is essential.
2 and 3 is a means for detecting the operating state of the internal combustion engine, that is, the rotational speed of the internal combustion engine, the exhaust gas temperature, and the like, and based on the detection result, It is preferable that the air-fuel ratio in the combustion gas injected from the regeneration device for the exhaust purification member is controlled.

6). Exhaust passage The exhaust passage 20 shown in FIGS. 2 and 3 is connected to the exhaust port 22 of the internal combustion engine, and the other end is connected to the exhaust purification members 36 and 44. The cross-sectional shape of the exhaust passage 20 is not particularly limited as long as it is a circular, elliptical, or prismatic exhaust passage 20.
However, in order to make it easier to attach the regeneration device for the exhaust purification member of the present invention to supply a predetermined amount of carbon monoxide, fuel gas, and a predetermined amount of heat to the exhaust purification member independently of the internal combustion engine. As illustrated in FIGS. 2 and 3, a bent portion 28 is preferably provided in the middle of the exhaust passage 20. And it is preferable to be comprised so that the regeneration apparatus 10 of the exhaust purification member of this invention can be connected to the bending part 29 via the injection outlet 16. FIG.

7). Exhaust gas purification member As an exhaust gas purification member to be regenerated, a diesel particulate filter (DPF) 36 and a NOx storage catalyst (LNT) 44 are typical as illustrated in FIGS. 2 and 3.
Such a diesel particulate filter can be made of a known material. For example, it is a filter having a honeycomb structure made of a ceramic material, and collects PM and other fine particles in exhaust gas to purify it. Is.
Here, it is preferable that the oxidation catalyst 32 is provided on the upstream side of the particulate filter 36. This is because before introducing exhaust gas into the diesel particulate filter 36, HC, NOx, etc. contained in the exhaust gas can be oxidized. Further, when the diesel particulate filter 36 becomes clogged, the regenerating apparatus of the present invention efficiently activates the oxidation catalyst 32 at a temperature and heats and oxidizes PM or the like adsorbed on the filter 36. This is because it can be reproduced.

The NOx occlusion catalyst can also be made of a known material. For example, platinum (Pt), potassium (K), sodium (Na), cesium (Cs), barium ( It can be constituted by supporting at least one elemental compound such as Ba), calcium (Ca), lanthanum (La), yttrium (Y), rhodium (Rb).
When the temperature of the NOx occlusion catalyst is lowered, the regeneration device of the present invention blows high-temperature combustion gas to raise the temperature of the catalyst to the activation temperature or higher and is contained in the combustion gas. The NOx compound is reduced and released using carbon monoxide and fuel gas as a reducing agent to regenerate the NOx storage catalyst.

8). Regeneration Method Next, an exhaust purification member regeneration method that is performed using the exhaust purification member regeneration device of the present invention will be described. Such an exhaust purification member regeneration method detects an operating state of an internal combustion engine such as a diesel engine by an operating state detection means and injects combustion gas from a burner at an air-fuel ratio corresponding to the detected operating state. It is a feature.
That is, when the internal combustion engine is normally operated, the exhaust temperature becomes relatively high, and NOx reduction reaction, PM combustion, and the like are efficiently performed in the NOx storage catalyst and the diesel particulate filter. On the other hand, when the engine is started or idling, the exhaust temperature becomes low, and the temperature of the NOx storage catalyst or diesel particulate filter cannot be raised. Therefore, the reduction of NOx adsorbed on these exhaust purification members is reduced. It becomes difficult to perform reaction and combustion of PM or the like. Therefore, on the upstream side of the exhaust purification member, the combustion gas is injected by setting the air-fuel ratio in the burner from the burner connected via the injection outlet communicating with the exhaust passage in accordance with the operating state of the internal combustion engine. Thus, the exhaust purification member can be efficiently regenerated.
The exhaust gas purification member regeneration apparatus according to the present invention includes a predetermined burner and an oxidation catalyst for oxidizing the combustion gas injected from the burner. Therefore, the air-fuel ratio is accurately controlled in the burner. While performing well, carbon monoxide can be efficiently produced in the oxidation catalyst. Therefore, regeneration of the NOx storage catalyst and the diesel particulate filter can be performed more efficiently.

For example, when the NOx storage catalyst is regenerated, the temperature of the NOx storage catalyst is raised to the activation temperature or higher by the amount of heat in the combustion gas, while the fuel gas and carbon monoxide can be used as a reducing agent for NOx. In addition, NOx can be efficiently reduced and the NOx storage catalyst can be regenerated very efficiently.
That is, according to the exhaust gas purification member regeneration apparatus of the present invention, the fuel gas contained in the combustion gas is not only incompletely combusted due to residual heat or the like to generate carbon monoxide, but also efficiently by the oxidation catalyst. Carbon oxide can be generated. Therefore, since the content of carbon monoxide in the combustion gas can be effectively increased and the combustion gas can be injected, the regeneration efficiency of the NOx storage catalyst can be significantly improved.

Also, when regenerating a diesel particulate filter, the amount of heat contained in the combustion gas injected from the regenerator of the present invention is introduced into an oxidation catalyst arranged upstream of the filter to activate the oxidation catalyst. It can be heated above the temperature. Then, carbon monoxide and fuel gas as heat generating agents contained in the combustion gas undergo an oxidation reaction by the oxidation catalyst, so that the temperature of the combustion gas further increases. Therefore, the diesel particulate filter can be regenerated extremely efficiently by efficiently heating the filter disposed downstream of the oxidation catalyst and oxidizing (burning) PM or the like adhering to the filter. .
At this time, as the heat generating agent, either fuel gas or carbon monoxide can be suitably used. Therefore, the filter is effectively heated by passing the oxidation catalyst upstream of the filter by the combustion gas containing a predetermined amount of fuel gas and carbon monoxide injected from the burner provided with the oxidation catalyst, and the diesel particulate filter It can be played back efficiently.

9. Air-fuel ratio (lambda value)
Further, it is preferable to inject the combustion gas so that the air-fuel ratio in the burner becomes a value within the range of less than 0.1 to 1.0. Moreover, it is preferable to control this air fuel ratio according to the driving | running state of internal combustion engines, such as a diesel engine.
The reason for this is that in the regenerator provided at the predetermined position as described above, by injecting the predetermined combustion gas so that the air-fuel ratio becomes a value within the predetermined range, the operating state of the diesel engine or the like is determined. This is because the exhaust purification member can be heated to a predetermined temperature or reduced.
More specifically, when the engine is started or idling, the exhaust temperature becomes low, and the temperature of the NOx storage catalyst or diesel particulate filter cannot be raised. It may be difficult to perform the reduction reaction of NOx and combustion of PM or the like. Therefore, the exhaust purification member can be regenerated more efficiently by injecting the combustion gas from the burner at an air-fuel ratio corresponding to the operating state of the diesel engine or the like.

  Here, referring to FIG. 4 to FIG. 7, when the diesel particulate filter is regenerated using the exhaust purification member regeneration device of the present invention, the set air-fuel ratio (lambda value) in the burner and the combustion gas The relationship between the total amount of carbon monoxide (CO) and fuel gas (THC) contained in the gas and the temperature of the exhaust gas will be described.

  First, as schematically shown in FIG. 4, when the concentration sensors 61a and 61b are arranged before and after the oxidation catalyst 13 in the exhaust purification member regeneration device 10 of the present invention, and the set air-fuel ratio in the burner 12 is changed. Measurement of the amounts of carbon monoxide (CO) and fuel gas (THC) contained in the combustion gas before and after the combustion gas injected from the burner 12 passes through the oxidation catalyst 13 provided in the regenerator 10. went. Based on the obtained results, FIG. 5 shows the lambda value (−) as the set air-fuel ratio in the burner and the combustion gas before and after the combustion gas injected from the burner 12 passes through the oxidation catalyst 13. The relationship with the quantity (vol%) of carbon monoxide (CO) and fuel gas (THC) contained is shown. In FIG. 5, line A shows the amount of fuel gas contained in the combustion gas before passing through the oxidation catalyst 13, and line B shows the amount of fuel gas contained in the combustion gas after passing through the oxidation catalyst 13. ing. Further, the amount of carbon monoxide (CO) contained in the combustion gas before line C passes through the oxidation catalyst 13, and the amount of carbon monoxide (CO) contained in the combustion gas after line D passes through the oxidation catalyst 13. The amount of each is shown.

As can be easily understood from FIG. 5, by controlling the set air-fuel ratio (lambda value) in the burner within a predetermined range, the fuel gas is incompletely burned in the burner, and carbon monoxide is contained in the combustion gas. In addition, a predetermined amount of the fuel gas can be included, and carbon monoxide (CO) can be efficiently generated in the oxidation catalyst. That is, for example, when the lambda value is about 0.9, the amount of carbon monoxide and fuel gas contained in the combustion gas can be reduced to about 0.001 vol% by passing the oxidation catalyst. When the lambda value is about 0.5, the amount of carbon monoxide contained in the combustion gas before passing through the oxidation catalyst is about 17 vol%, and the amount of fuel gas is about 2.5 vol% or more. In addition to reducing the amount of fuel gas contained in the combustion gas by passing the oxidation catalyst, the amount of carbon monoxide can be increased to about 20 vol%.
In particular, when the air-fuel ratio (lambda value) is set to a value of 0.6 or less, the ratio of carbon monoxide (CO) that is oxidized by passing through the oxidation catalyst 13 to carbon dioxide (CO ₂ ) is small. Therefore, the amount of carbon monoxide (CO) after passing through the oxidation catalyst is greater than the amount of carbon monoxide before passing through. Therefore, considering that carbon monoxide (CO) and fuel gas (HC) generally have an effect on the regeneration of the exhaust purification member, it is generally said that carbon monoxide is superior to fuel gas. The set air-fuel ratio (lambda value) in the burner is preferably a value within a range of less than 0.1 to 1.0, more preferably a value within a range of 0.15 to 0.8, More preferably, the value is 0.2 to 0.6 or less.

  Next, as schematically shown in FIG. 6, temperature sensors and concentration sensors 62 a and 62 b are arranged before and after the oxidation catalyst 32 in the diesel particulate filter provided with the oxidation catalyst 32 on the upstream side. When the set air-fuel ratio was changed, the temperature (° C.) of the exhaust gas before and after passing through the oxidation catalyst 32 provided on the upstream side of the diesel particulate filter was measured. Based on the obtained results, FIG. 7 shows changes in exhaust gas temperature (° C.) before and after passage of the oxidation catalyst 32 in the diesel particulate filter provided with the oxidation catalyst 32 on the upstream side, The relationship between the lambda value (−), which is the set air-fuel ratio in the burner in the exhaust purification member regeneration device of the invention, and the amounts (vol%) of carbon monoxide (CO) and fuel gas (HC) contained therein Show. In FIG. 7, line A indicates a 120 ° C. line that is the temperature of exhaust gas discharged from the diesel engine, and line B passes the lambda value and the oxidation catalyst 32 disposed upstream of the diesel particulate filter. The relationship between the exhaust gas temperature and the line C indicates the relationship between the lambda value and the exhaust gas temperature after passing through the oxidation catalyst 32 disposed upstream of the diesel particulate filter. Line D shows the characteristic relationship between the lambda value and the amount of carbon monoxide in the combustion gas, and Line E shows the characteristic relationship between the lambda value and the amount of fuel gas in the combustion gas. ing.

As can be easily understood from FIG. 7, if the set air-fuel ratio (lambda value) in the burner is a value within a predetermined range, a predetermined amount of carbon monoxide and fuel gas can be included in the combustion gas. . That is, for example, when the lambda value is about 0.9, the amounts of carbon monoxide and fuel gas contained in the combustion gas can be about 0.001 vol%, respectively, and the diesel particulate filter The exhaust gas temperature can be raised by about 150 ° C. before and after the passage of the oxidation catalyst 32 provided on the upstream side.
Further, when the lambda value is about 0.5, the amount of carbon monoxide contained in the combustion gas can be about 7.5 vol%, the amount of fuel gas can be about 5 vol%, and such an oxidation catalyst. Before the passage of the exhaust gas 32, the temperature of the exhaust gas is about 70 ° C. However, after the passage of the oxidation catalyst 32 and reaching the diesel particulate filter, the exhaust gas temperature may be further increased by about 200 ° C. it can.

Further, when the lambda value is set to a value of 0.5 or less, the amount of carbon monoxide and fuel gas contained in the combustion gas is considered to increase gradually after the passage of the oxidation catalyst 32. The temperature of the exhaust gas when reaching the diesel particulate filter (line C in FIG. 7) is considered to be at least leveled off.
Therefore, the air-fuel ratio (lambda value) in the burner is preferably set to a value within the range of less than 0.1 to 1.0, more preferably set to a value within the range of 0.15 to 0.8. More preferably, the value is in the range of 2 to 0.6. By incomplete combustion to achieve such an air-fuel ratio, a predetermined amount of carbon monoxide or fuel gas is burned at a high temperature of 250 to 1,200 ° C. with respect to a diesel particulate filter, a NOx storage catalyst, or the like. This is because it can be sprayed together with the gas, and regeneration of these filters, NOx storage catalyst, and the like can be performed extremely efficiently.

That is, it is understood that regeneration of the NOx storage catalyst and the diesel particulate filter is greatly affected by the set air-fuel ratio in the burner, the amount of carbon monoxide and fuel gas, and the amount of heat contained in the combustion gas.
According to the present invention, as shown in FIGS. 2 and 3, the upstream side of the exhaust purification members 36 and 44 is connected via the injection outlet 16 communicating with the exhaust passage 20, and the predetermined burner 12 and the oxidation are connected. By injecting combustion gas from the regenerator 10 equipped with the catalyst 13, it is very easy to adjust the amounts of carbon monoxide, fuel gas, and heat contained in the combustion gas within a predetermined range. Further, by increasing the amount of carbon monoxide in the combustion gas by the oxidation catalyst 13 for oxidizing the combustion gas, in particular, the regeneration efficiency of the NOx storage catalyst can be further improved.

As described above, according to the present invention, the regeneration device for the exhaust purification member includes the predetermined burner and the oxidation catalyst, so that it is easy to control the set air-fuel ratio of the burner corresponding to the operating engine of the internal combustion engine. In addition, the amount of carbon monoxide, fuel gas, and heat contained in the combustion gas can be efficiently controlled. Therefore, it is possible to provide a regenerator that can efficiently regenerate exhaust purification members such as a diesel particulate filter (DPF) and a NOx storage catalyst (LNT).
Further, according to the present invention, a diesel particulate filter (DPF) or a diesel particulate filter (DPF) is connected to the upstream side of the exhaust purification member via an injection outlet communicating with the exhaust passage, regardless of the operating state of the diesel engine or the like. It is possible to provide an exhaust purification member regeneration device capable of independently regenerating NOx storage catalyst (LNT) or the like.
In addition, although the regeneration method and regeneration apparatus of the exhaust purification member of the present invention can each be a switching regeneration system, it can also be a continuous regeneration system that performs regeneration simultaneously with the operation by a diesel engine or the like.

It is a figure provided in order to demonstrate the reproducing | regenerating apparatus of the exhaust purification member of this invention. It is a figure which shows the state which equipped the reproducing | regenerating apparatus of this invention in the exhaust passage of the internal combustion engine containing a diesel particulate filter (DPF). It is a figure which shows the state equipped with the regeneration apparatus of this invention in the exhaust passage of the internal combustion engine containing a NOx storage catalyst (LNT). It is a figure provided in order to demonstrate the measuring method of the characteristic of the combustion gas before and behind passage of an oxidation catalyst in the reproducing | regenerating apparatus of this invention. It is a characteristic view which shows the relationship between the air-fuel ratio (lambda value) of combustion gas, and the amount of carbon monoxide and fuel gas contained in the combustion gas before and after passing through the oxidation catalyst in the regenerating apparatus of the present invention. It is a figure provided in order to demonstrate the measuring method of the temperature of the exhaust gas before and behind passage of the oxidation catalyst arrange | positioned upstream of the diesel particulate filter. It shows the relationship between the air-fuel ratio (lambda value) of the combustion gas and the temperature of the exhaust gas before and after passing through the oxidation catalyst disposed upstream of the carbon monoxide, fuel gas, and diesel particulate filter in the combustion gas. FIG. (A) And (b) is a figure provided in order to demonstrate the reproducing | regenerating method using the conventional aspirator burner. (A) And (b) is a figure provided in order to demonstrate the regeneration method of the diesel particulate filter (DPF) provided with the conventional catalyst burner. (A) And (b) is a figure provided in order to demonstrate the reproducing | regenerating method using the conventional burner. It is a figure provided in order to demonstrate the regeneration method of the NOx storage catalyst (LNT) using the conventional reduction | restoration nozzle.

Explanation of symbols

10: Regenerative device for exhaust purification member 12: Burner 13: Oxidation catalyst 16: Injection outlet 18: Temperature sensor 20: Exhaust passage 22: Exhaust port 24 of internal combustion engine 24: Lambda sensor 28: Bending part 30, 38: Catalyst case 32: Oxidation catalyst 36: Diesel particulate filter (DPF)
44: NOx occlusion catalyst 60: injector 70: first air introduction pipe 72: glow plug 80: orifice 81: fuel evaporation device 84: fuel ignition device 87: second air introduction tube 88: injection outlet

Claims (7)

An exhaust purification member regeneration device provided in an exhaust passage of an internal combustion engine for purifying exhaust gas, which injects a predetermined amount of combustion gas containing carbon monoxide (CO) and unburned fuel gas (HC) A regenerator for an exhaust purification member, comprising: a burner that oxidizes and an oxidation catalyst for oxidizing combustion gas injected from the burner.   The regeneration device for an exhaust purification member according to claim 1, wherein the regeneration device for the exhaust purification member is connected to an upstream side of the exhaust purification member via an injection outlet communicating with the exhaust passage.   The burner is vaporized with an injector for supplying fuel, a first air introduction pipe for mixing air with the fuel, a fuel evaporation device for heating and evaporating the supplied fuel An orifice for diffusing and injecting the fuel; a second air introduction pipe for taking in air for assisting combustion of the fuel; and a fuel ignition device for igniting the injected fuel into combustion gas The regeneration device for an exhaust purification member according to claim 1 or 2, characterized in that   The regeneration device for an exhaust purification member according to any one of claims 1 to 3, wherein an air-fuel ratio in the burner is set to a value within a range of less than 0.1 to 1.0.   5. The regeneration device for an exhaust purification member according to claim 4, further comprising a lambda sensor for measuring an air-fuel ratio in the exhaust gas between the injection outlet and the exhaust purification member.   The exhaust purification member regeneration device according to any one of claims 1 to 5, wherein the exhaust purification member includes a particulate filter provided with an NOx occlusion catalyst or an oxidation catalyst on the upstream side. In a method for regenerating an exhaust purification member provided in an exhaust passage of an internal combustion engine for purifying exhaust gas,
An operating state detecting means for detecting an operating state of the internal combustion engine;
A burner that is connected to an upstream side of the exhaust purification member via an injection outlet communicating with the exhaust passage and injects a combustion gas containing a predetermined amount of carbon monoxide (CO) and unburned fuel gas (HC). And an oxidation catalyst for oxidizing the combustion gas injected from the burner ,
Combusting so that the combustion gas that has passed through the oxidation catalyst contains a predetermined amount of carbon monoxide (CO) and unburned fuel gas (HC) according to the operating state of the internal combustion engine detected by the operating state detection means. A method for regenerating an exhaust purification member, characterized by injecting gas.

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