JP2004108194A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and certainly eliminate particulates collected on a filter of an exhaust emission control device for eliminating particulates (PM), or particulate matters included in exhaust gas from an internal combustion engine of an diesel engine and the like. <P>SOLUTION: This device is equipped with an upstream side exhaust shutter positioned on the upstream of a filter means to open/close an exhaust passage, and a downstream side exhaust shutter that is positioned on the downstream of the filter means to open/close the exhaust passage, a high pressure gas supplying means that supplies high pressure gas between the filter means on the exhaust passage and the downstream side exhaust shutter at the time of back washing of the filter means, and a particulate collecting means that is positioned between the upstream side exhaust shutter on the exhaust passage and the filter means to collect particulates moved from the filter means to the upstream side by back washing of the filter means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust gas purification device for removing particulate matter (PM), which is a particulate matter contained in exhaust gas discharged from an internal combustion engine such as a diesel engine.
[0002]
[Prior art]
BACKGROUND ART Conventionally, a diesel particulate filter (DPF) has been frequently used as a device for preventing particulates contained in exhaust gas discharged from a diesel engine from being discharged to the atmosphere.
This diesel particulate filter is generally configured to periodically heat the filter from the outside and oxidize and regenerate the collected particulates.
[0003]
Conventionally, as such a diesel particulate filter, for example, a filter that regenerates by burning particulates collected in the filter by an electric heater is known.
In contrast, as disclosed in JP-A-10-159552, and generate to N0 ₂ oxidizes NO in the exhaust gas by the oxidation catalyst disposed upstream of the filter, the heat of the exhaust gas When N0 ₂ diesel particulate filter, called a continuous regeneration type for reproducing continuously oxidizing the particulate matter trapped in the filter (CRT) has been attracting attention recently by.
[0004]
That is, in the former general diesel particulate filter, it is known that two filters are arranged in parallel to sequentially regenerate and collect, but the collected particulate is burned to burn the diesel particulate. At present, a device for regenerating the curated filter is required, and it is not widely used because of its high cost and difficulty in mounting.
[0005]
The latter continuous regeneration type contrast, since it only provided an oxidation catalyst for generating to N0 ₂ oxidizes NO in the exhaust gas upstream of the filter, for regenerating the diesel particulate filter Since it is continuously regenerated without the need for a special device, it can be practically realized with one system of a catalyst and a filter.
Therefore, the former general diesel particulate filter is low in cost and excellent in mountability.
[0006]
The mechanism in which the collected particulates burn in the diesel particulate filter called a continuous regeneration type will be described.
As described above, in this diesel particulate filter, an oxidation catalyst is disposed in front of a filter that collects particulates.
In this oxidation catalyst,
2NO + O ₂ → 2NO ₂
Oxidation reaction occurs, and the particulate collected in the filter is C + 2NO ₂ → CO ₂ + 2NO
The diesel particulate filter is regenerated by burning due to the oxidation reaction of.
[0007]
When the ambient temperature of the filter reaches about 600 ° C. or more, the particulates directly react with oxygen and burn.
However, the above oxidation reaction is less likely to occur below a certain temperature, which is about 250-300 ° C.
Therefore, when the temperature falls below this temperature, the oxidation reaction hardly occurs, and the particulates collected by the filter continue to accumulate without burning much.
[0008]
Therefore, when a vehicle equipped with a continuously regenerating diesel particulate filter travels under conditions where the exhaust gas temperature is always low, such as when traveling only in urban areas, the particulates accumulate on the filter without burning and are discharged. The pressure rises, causing a decrease in output and a deterioration in fuel efficiency.
In addition, when the exhaust gas temperature rises and the regeneration is started, for example, by high-speed running after a considerable amount of particulates are deposited, the deposited particulates burn rapidly and the temperature in the filter rises sharply. However, there is a problem that the filter is cracked or damaged due to abnormal heat generation, and the durability of the filter is significantly reduced.
[0009]
Therefore, conventionally, as a countermeasure for solving such a problem, a heater or a burner is added to a continuous regeneration type diesel particulate filter to burn the particulates, or the exhaust gas temperature is reduced by post-injection. A method of promoting a continuous regeneration reaction of particulates by the increase has been studied.
[0010]
[Patent Document 1]
JP-A-10-159552
[Problems to be solved by the invention]
However, a system in which a heater or a burner is added to the continuous regeneration type diesel particulate filter to burn the particulates, or a method in which the continuous regeneration reaction of the particulates is promoted by increasing the exhaust gas temperature by post-injection, is used in the system. However, there is a problem that the cost is increased and the cost is increased.
[0012]
In addition, these countermeasures are complicated in system and must be combined with control on the engine side, so that it is difficult to equip them with already marketed automobiles.
The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide an exhaust gas purifying apparatus capable of easily and surely removing particulates captured by a filter.
[0013]
[Means for Solving the Problems]
The exhaust gas purifying apparatus according to claim 1, further comprising: a filter arranged in an exhaust passage of the engine to capture particulates in exhaust gas; and an upstream exhaust shutter arranged upstream of the filter to open and close the exhaust passage. A downstream exhaust shutter arranged downstream of the filter means for opening and closing the exhaust passage, and a high-pressure gas between the filter means and the downstream exhaust shutter of the exhaust passage when the filter means is backwashed. A high-pressure gas supply unit for supplying, and the upstream-side exhaust shutter of the exhaust passage, which is disposed between the filter unit and the upstream-side exhaust shutter, collects the particulates moved upstream from the filter unit by the backwashing of the filter unit. And particulate collecting means.
[0014]
According to a second aspect of the present invention, in the exhaust gas purifying apparatus according to the first aspect, the filter means is a continuous regeneration type particulate filter for continuously oxidizing particulates collected by the filter and regenerating the filter. There is a feature.
The exhaust gas purifying apparatus according to claim 3 is the exhaust gas purifying apparatus according to claim 1 or 2, wherein the high-pressure gas supply means includes a high-pressure air tank provided between the filter means in the exhaust passage and the downstream exhaust shutter. It is characterized by comprising a supply pipe to be connected, and an on-off valve arranged in the supply pipe to open and close the supply pipe.
[0015]
According to a fourth aspect of the present invention, there is provided the exhaust gas purification apparatus according to any one of the first to third aspects, wherein the particulate collection means includes an intake section disposed in the exhaust passage, and the intake section. And a collecting container detachably disposed below the insertion portion.
According to a fifth aspect of the present invention, there is provided the exhaust gas purification apparatus according to the fourth aspect, wherein the intake portion has a space protruding upward from the exhaust passage.
[0016]
(Action)
In the exhaust gas purifying apparatus according to the first aspect, first, the upstream exhaust shutter and the downstream exhaust shutter disposed upstream and downstream of the filter means in the exhaust passage are closed.
Next, the high-pressure gas supply means is operated, high-pressure gas is supplied between the filter means in the exhaust passage and the downstream exhaust shutter, and the filter means is backwashed by the high-pressure gas.
[0017]
Then, the particulates moved to the upstream side by the backwashing of the filter means are collected by the particulate collection means.
In the exhaust gas purifying apparatus according to the second aspect, the filter means is a continuous regeneration type particulate filter that continuously oxidizes the particulates collected by the filter and regenerates the filter, and accumulates on the continuous regeneration type particulate filter. The removed particulates are removed.
[0018]
In the exhaust gas purifying apparatus according to the third aspect, when the on-off valve arranged in the supply pipe is opened, the high-pressure air in the high-pressure air tank passes through the supply pipe and is supplied between the filter means in the exhaust passage and the downstream exhaust shutter. Is done.
In the exhaust gas purifying apparatus according to the fourth aspect, the particulate collecting means has a capturing portion disposed in the exhaust passage and a collecting container detachably disposed below the capturing portion.
[0019]
Then, by removing the collection container from the intake unit, the particulates collected in the collection container are discarded, and after the disposal, the collection container is attached to the intake unit.
In the exhaust gas purifying apparatus of claim 5, the intake section has a space protruding upward from the exhaust passage, and the particulates moved from the filter means to the intake section by backwashing are temporarily stored in the space. After staying, it falls into the collection container by the action of gravity and is collected in the collection container.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of the exhaust gas purification apparatus of the present invention. In this embodiment, the present invention is applied to a vehicle such as a truck equipped with a diesel engine.
In FIG. 1, reference numeral 11 denotes a diesel engine arranged in a vehicle such as a truck.
[0021]
An exhaust pipe 15 forming an exhaust passage is connected to the exhaust manifold 13 of the diesel engine 11.
The exhaust pipe 15 is provided with a filter means 17 for capturing particulates in the exhaust gas.
The filter means 17 is a continuous regeneration (CRT) diesel particulate filter (DPF) that continuously oxidizes the particulates collected by the filter 19 and regenerates the filter.
[0022]
The filter means 17 has a cylindrical casing 21, and a filter 19 is accommodated in the casing.
The filter 19 is made of a porous material such as cordierite, mullite, and silicon carbide, and carries a noble metal oxidation catalyst component as an oxidation catalyst.
In this continuous regeneration type diesel particulate filter, the oxidation catalyst carried on the filter 19
2NO + O ₂ → 2NO ₂
Oxidation reaction occurs, and the particulates collected in the filter 19 are
C + 2NO ₂ → CO ₂ + 2NO
The diesel particulate filter is regenerated by burning due to the oxidation reaction of.
[0023]
An upstream exhaust shutter 23 that opens and closes an exhaust passage of the exhaust pipe 15 is disposed upstream of the filter unit 17.
The upstream side exhaust shutter 23 can be electrically opened and closed.
[0024]
A downstream exhaust shutter 25 that opens and closes an exhaust passage of the exhaust pipe 15 is disposed downstream of the filter unit 17.
The downstream exhaust shutter 25 can be electrically opened and closed.
A high-pressure gas supply unit 27 that supplies high-pressure gas when the filter unit 17 is backwashed is disposed between the filter unit 17 of the exhaust pipe 15 and the downstream exhaust shutter 25.
[0025]
The high-pressure gas supply means 27 has a supply pipe 31 which forms a supply pipe connecting the high-pressure air tank 29 between the filter means 17 of the exhaust pipe 15 and the downstream exhaust shutter 25.
The supply pipe 31 is provided with an on-off valve 33 composed of an electromagnetic valve for opening and closing the supply pipe.
[0026]
Between the upstream exhaust shutter 23 of the exhaust pipe 15 and the filter means 17, a particulate collection means 35 for collecting particulates which have moved upstream from the filter means 17 due to backwashing of the filter means 17 is arranged. ing.
As shown in FIG. 2, the particulate collecting means 35 includes a particulate intake portion 37 disposed in an exhaust passage of the exhaust pipe 15 and a particulate detachably disposed below the intake portion 37. And a collecting container 39.
[0027]
The intake section 37 is connected to the exhaust pipe 15 by welding W or the like.
A space 37 a projecting upward from the exhaust pipe 15 is formed in an upper portion of the intake section 37.
A flange portion 37b is formed at a lower end of the intake portion 37.
A flange portion 39a formed at the upper end of the collection container 39 is detachably fixed to the flange portion 37b by fastening means including a bolt 41 and a nut 43.
[0028]
The operation of the exhaust gas purifying apparatus described above is performed in a state where the diesel engine 11 is stopped by an alarm from a vehicle such as a truck on which the diesel engine 11 is mounted.
That is, the vehicle is provided with, for example, an alarm unit (not shown) that detects a differential pressure between the inlet side and the outlet side of the filter unit 17 and issues an alarm when the differential pressure exceeds a predetermined value.
[0029]
When a predetermined amount of unburned particulates accumulates on the filter 19 of the filter means 17, the pressure difference between the inlet side and the outlet side of the filter means 17 exceeds a predetermined value, and an alarm is issued to the driver.
The driver stops the vehicle at an appropriate place by this warning, stops the diesel engine 11, and removes the particulates by the exhaust gas purification device.
[0030]
That is, first, the upstream exhaust shutter 23 and the downstream exhaust shutter 25 arranged upstream and downstream of the filter means 17 of the exhaust pipe 15 are closed. Next, the on-off valve 33 arranged in the supply pipe 31 of the high-pressure gas supply means 27 is opened, and the high-pressure air in the high-pressure air tank 29 passes through the supply pipe 31, and the filter means 17 of the exhaust pipe 15 and the downstream exhaust shutter 25. Is supplied between
[0031]
The supplied high-pressure air passes through the filter 19 of the filter means 17, and the filter 19 is backwashed.
The backwashing of the filter 19 is performed by opening and closing the on-off valve 33 disposed in the supply pipe 31 a plurality of times at predetermined intervals.
Then, the particulates moved to the upstream side by the backwashing of the filter means 17 are collected by the particulate collection means 35.
[0032]
That is, the particulate PM that has moved upstream due to the backwashing of the filter 19 reaches the intake section 37 of the particulate collection means 35, and falls naturally into the collection container 39 from the intake section 37.
[0033]
In addition, a part of the particulate PM stays in the space 37 a protruding upward from the exhaust pipe 15 and then falls naturally into the collection container 39.
After a predetermined time, the collection container 39 is removed from the intake unit 37, and the particulate PM captured in the collection container 39 is discarded at a predetermined place. 37 is attached again.
[0034]
In the exhaust gas purification device described above, the upstream exhaust shutter 23 and the downstream exhaust shutter 25 are closed, and the high-pressure gas supply unit 27 supplies high-pressure gas between the filter unit 17 of the exhaust pipe 15 and the downstream exhaust shutter 25. Then, the filter means 17 was backwashed by high-pressure gas, and the particulates moved to the upstream side by the backwashing of the filter means 17 were collected by the particulate collection means 35. Particulates can be easily and reliably removed.
[0035]
A heater and a burner are added to the continuous regeneration type diesel particulate filter to burn the particulates, or a method that promotes the continuous regeneration reaction of the particulates by increasing the exhaust gas temperature by post-injection. Thus, the system can be simplified.
In addition, since the system is simple, it can be easily and inexpensively mounted on a commercially available automobile.
[0036]
In the exhaust gas purification apparatus described above, when the on-off valve 33 disposed on the supply pipe 31 is opened, the high-pressure air in the high-pressure air tank 29 passes through the supply pipe 31, and the filter means 17 of the exhaust pipe 15 and the downstream exhaust shutter 25. Therefore, the high-pressure gas supply means 27 can be configured easily and reliably.
Further, in the above-described exhaust gas purification device, by removing the collection container 39 from the intake section 37, the particulates collected in the collection container 39 can be easily and reliably discarded.
[0037]
In the exhaust gas purifying apparatus described above, the particulates moved from the filter unit 17 to the intake unit 37 by backwashing temporarily stay in the space 37a and then fall into the collection container 39 by the action of gravity. In addition, the backwashed particulates can be reliably collected.
In the exhaust gas purifying apparatus described above, the upstream exhaust shutter 23 and the downstream exhaust shutter 25 are provided before and after the filter means 17, so that a small amount of air from the high-pressure air tank 27 can be used effectively.
[0038]
Note that, in the above-described embodiment, an example in which the filter unit 17 is configured by supporting a noble metal oxidation catalyst component as an oxidation catalyst on a porous material has been described, but the present invention is not limited to such an embodiment. For example, the filter means 17 may be configured to be separated into a member for supporting an oxidation catalyst and a member for capturing particulates.
[0039]
Further, in the above-described embodiment, the example in which the upstream exhaust shutter 23 and the downstream exhaust shutter 25 are separately installed in the exhaust pipe 15 has been described. However, the present invention is not limited to this embodiment. An exhaust brake valve mounted on a vehicle can be diverted to either the side exhaust shutter 23 or the downstream exhaust shutter 25, and when diverted, the cost can be reduced.
[0040]
Further, in the above-described embodiment, an example in which the present invention is applied to a continuous regeneration type particulate filter that continuously oxidizes particulates collected by the filter 19 and regenerates the filter has been described. The present invention is not limited to the embodiment, and may be applied to a conventional particulate filter that regenerates by burning the particulates collected in the filter 19 by an electric heater or the like.
[0041]
In the above-described embodiment, an example in which the present invention is applied to the purification of exhaust gas from the diesel engine 11 has been described. However, the present invention is not limited to such an embodiment. Can be widely applied to.
Further, in the above-described embodiment, an example has been described in which the backwash is performed when the differential pressure across the filter means 17 exceeds a predetermined value. However, the present invention is not limited to such an embodiment. Alternatively, the determination may be made based on the exhaust pressure of the diesel engine, or may be performed periodically.
[0042]
【The invention's effect】
As described above, in the exhaust gas purifying apparatus of the first aspect, the upstream exhaust shutter and the downstream exhaust shutter are closed, and high-pressure gas is supplied between the filter means in the exhaust passage and the downstream exhaust shutter by the high-pressure gas supply means. Since the filter means is supplied and the filter means is backwashed by the high-pressure gas, and the particulates moved to the upstream side by the backwash of the filter means are collected by the particulate collection means, the particulate matter collected by the filter is collected. Can be easily and reliably removed.
[0043]
According to the second aspect of the present invention, the particulates accumulated on the continuous regeneration type particulate filter can be easily and surely removed.
In the exhaust gas purifying apparatus according to the third aspect, when the on-off valve arranged in the supply pipe is opened, the high-pressure air in the high-pressure air tank passes through the supply pipe and is supplied between the filter means in the exhaust passage and the downstream exhaust shutter. Therefore, the high-pressure gas supply means can be easily and reliably configured.
[0044]
According to the fourth aspect of the present invention, by removing the collecting container from the intake section, the particulates collected in the collecting container can be easily and reliably discarded. In the exhaust gas purifying apparatus according to the fifth aspect, the particulates moved from the filter means to the intake portion by the backwashing temporarily stay in the space, and then fall into the collection container by the action of gravity. Collected particulates can be reliably collected.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing one embodiment of an exhaust gas purification device of the present invention.
FIG. 2 is an explanatory diagram showing details of a particulate collection unit in FIG. 1;
[Explanation of symbols]
Reference Signs List 11 Diesel engine 15 Exhaust pipe 17 Filter means 19 Filter 23 Upstream exhaust shutter 25 Downstream exhaust shutter 27 High-pressure gas supply means 29 High-pressure air tank 31 Supply pipe 33 Open / close valve 35 Particulate collection means 37 Intake section 37a Space section 39 Capture Collection container PM particulate

Claims (5)

Filter means arranged in an exhaust passage of the engine to capture particulates in exhaust gas;
An upstream exhaust shutter disposed upstream of the filter means to open and close the exhaust passage;
A downstream exhaust shutter that is arranged downstream of the filter means and opens and closes the exhaust passage;
High-pressure gas supply means for supplying high-pressure gas between the filter means of the exhaust passage and the downstream exhaust shutter at the time of back washing of the filter means,
Particulate collection means disposed between the upstream exhaust shutter of the exhaust passage and the filter means for collecting the particulates moved upstream from the filter means by backwashing the filter means;
An exhaust gas purification device comprising: The exhaust gas purification device according to claim 1,
The exhaust gas purifying apparatus, wherein the filter means is a continuous regeneration type particulate filter that continuously oxidizes the particulates collected by the filter and regenerates the filter. The exhaust gas purification apparatus according to claim 1 or 2,
The high-pressure gas supply means,
A supply pipe connecting a high-pressure air tank between the filter means of the exhaust passage and the downstream exhaust shutter,
An on-off valve arranged in the supply line for opening and closing the supply line,
An exhaust gas purification device comprising: The exhaust purification device according to any one of claims 1 to 3,
The particulate collection means,
An intake unit disposed in the exhaust passage;
A collecting container detachably disposed below the intake unit,
An exhaust gas purification device comprising: The exhaust gas purification apparatus according to claim 4,
The exhaust gas purifying device, wherein the intake portion has a space that projects upward from the exhaust passage.

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