JPH05133216A - Particulate trap for diesel engine - Google Patents

Abstract

PURPOSE:To prevent an electric heater for igniting particulates from being broken out due to abnormal heating in a particulate trap for a diesel engine. CONSTITUTION:A particulate receiving portion 53 is disposed under a filter 37 provided on the way of an exhaust passage. A wire net 73 is arranged near above an electric heater 55 mounted on the bottom of the particulate receiving portion 53, for dropping particulates which are peeled from the filter 37 in uniform timing by back washing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fine particles containing carbon as a main component in exhaust gas of a diesel engine and containing sulfides, iron oxides, condensates of unburned hydrocarbons, etc. (Referred to as particulates) for capturing and removing particulate traps for diesel engines.

[0002]

2. Description of the Related Art Exhaust gas emitted from a diesel engine contains a large amount of particulates containing carbon as a main component, and the emission level of nitrogen oxides (NOx) is higher than that of exhaust gas from a gasoline engine. There is a problem of being expensive.

Regarding NOx, since the residual oxygen concentration in the exhaust gas of a diesel engine is high, the three-way catalyst used for treating the exhaust gas of a gasoline engine cannot be diverted, and the exhaust gas treatment technology unique to the diesel engine is required. It is said that efforts have been made to develop a catalyst, but it has not yet reached a practical aim.

On the other hand, when adopting a relatively highly practical NOx reduction measure such as adjustment of the injection timing, NO
While x can be reduced, the emission of particulates tends to increase. For this reason, comprehensive exhaust gas treatment measures that combine NOx reduction measures and particulate removal measures are being studied.

Various particulate traps for diesel engines have already been developed and proposed as measures to remove particulates.

For example, Japanese Patent Application Laid-Open No. 57-35918 discloses a ceramic honeycomb filter as shown in FIGS.

This filter 1 has a so-called honeycomb structure having a plurality of cells 5 which are parallel to each other and are partitioned by partition walls 3. Particularly, as shown in FIG. 6, one end face A has about half the end faces of the cells 5a. The openings of are alternately closed by the seal material 7 in a checkered pattern, and at the other end face B,
The cell 5a closed on the end face A is open, and the cell 5b opened on the end face A is also closed by the sealing material 9.

When the exhaust gas of the diesel engine is introduced from one end surface B of this filter 1, as shown in FIG.
The exhaust gas is introduced into the cell 5a, which is a dust-containing gas flow path, and passes through the partition wall 3 having gas permeability. At that time, the particulates contained in the dust-containing gas are captured on the partition wall surface of the cell 5a. , And becomes a clean exhaust gas from which particulates have been removed, and flows out from the other end surface A through the cell 5b which is a clean gas flow path.

Further, Japanese Patent Application Laid-Open No. 56-124417 discloses a ceramic filter as shown in FIG.
The filter 11 has a rectangular parallelepiped outer shape as a whole,
A plurality of rectangular plate-like bodies 13 and 15 which are parallel to each other,
It is composed of ribs 17 and 21 and spacers 19 and 23. These plate-like bodies 13 and 15 and ribs 17 and 21,
Each of the spacers 19 and 23 is made of air-permeable porous ceramics having a filter function.

The plate-like bodies 13 form the upper surface and the lower surface of the filter 11, and the plate-like bodies 15 are arranged in parallel between the plate-like bodies 13 on the upper and lower surfaces. Between the plate-like bodies 13 and 15,
Ribs 17, spacers 19 running in the longitudinal direction of the filter 11
And ribs 21 and spacers 23 that run in the direction orthogonal to the above.
Are alternately arranged to connect the adjacent plate-shaped bodies 13 and 15 to each other. The rib 17 forms both side surfaces along the longitudinal direction between the plate-like bodies 13 and 15, and the spacer 19 divides the space between the ribs 17 into a plurality of parts to form a gas passage 25 along the longitudinal direction. ing. Similarly, the rib 21 is formed in the plate-shaped body 1.
Both side surfaces of the ribs 21 between the ribs 21 and 3 are formed along the direction orthogonal to the above, and the spacers 23 divide the ribs 21 into a plurality of portions to form a gas flow path 27 along the direction.

Therefore, the filter 11 has a plurality of gas flow paths 25 running in the longitudinal direction and a plurality of gas flow paths 27 running in a direction orthogonal to the gas flow paths 25, 27. Has a structure in which the upper and lower portions are alternately formed via the plate-shaped body 15. In addition, the gas flow paths 25 and 27
Both ends of each are open at the end faces of the filter 11 facing each other.

In this filter 11, the gas flow path 2
One of the two open end faces of 5 is directly or indirectly closed, and the exhaust gas of the diesel engine is introduced from the other open end face. When the exhaust gas of the diesel engine is simultaneously introduced from both open end faces, when the exhaust gas passes through the plate-shaped body 15 and flows out to the gas flow path 27, the plate-shaped body 15 serves as a filter surface and particulates become gas. It is captured on the inner surface of the flow path 25. The clean exhaust gas from which the particulates have been removed is discharged to the outside of the system through the gas flow path 27.

However, in the particulate trap using the filter as described above, the trapped particulates are accumulated on the filtering surface of the filter, and the filter is clogged with the passage of operating time, resulting in exhaust gas ventilation pressure loss. Increase and the output of the engine decreases.

Therefore, various methods for regenerating a filter clogged with particulates have been proposed. For example, in Japanese Utility Model Laid-Open No. 62-35849, a burner is provided on the upstream side of the exhaust gas inlet of the filter. Discloses a particulate trap in which the high temperature combustion gas ignites the particulate matter deposited on the filter surface of the filter, burns it, and incinerates it.

Further, in Japanese Patent Laid-Open No. 56-92318, the exhaust gas passage is divided into two systems, and a particulate trap is arranged in each passage, and regeneration of the filter of the particulate trap is performed alternately. A scheme has been proposed. In this case, as in the case of the above-mentioned regeneration of the filter, a method of igniting the particulates directly on the filtration surface of the filter, burning the particulates and incinerating them is adopted.

However, as described above, in the conventional device for incinerating the trapped particulates on the filter, the heat of combustion of the particulates causes the filter to melt, and the heat distribution due to the temperature distribution and thermal shock inside the filter. There is a problem that the filter is cracked due to the stress.

In the exhaust gas of the diesel engine,
It contains a non-negligible amount of non-combustible components (such as ash, iron emitted from diesel engines and pipes, etc.), and these non-combustible components cannot be removed by incineration, so they are accumulated on the filter and can be stored for a long period of operation. There is also a problem that the ventilation pressure loss of the filter increases.

In order to solve such a problem, the present applicant has already proposed a particulate trap for a diesel engine as shown in FIG.

The diesel engine particulate trap 31 is attached in the middle of an exhaust pipe 33 from the diesel engine, and a particulate is trapped in the casing 35 connected to the exhaust pipe 33 via an introduction pipe 57. A filter 37 for capturing the curate is fixed and accommodated via a sealing material 38.

As shown in FIGS. 10 and 11, the filter 37 is formed by combining a predetermined number of filter elements 43 made of a porous material. The filter element 43 has a plate shape as a whole, and has a plurality of dust-containing gas passages 39 penetrating from the upper side to the lower side. Filter element 43
A rib 41 extending in the thickness direction of the filter element 43 is formed above and below the filter element 43. A plurality of filter elements 43 are arranged so that the rib 41 abuts the back surface 45 of the adjacent filter element 43. The filters 37 are laminated to form a filter 37.

In the filter 37 thus constructed, as shown in FIG. 11, a plurality of dust-containing gas passages 39 penetrating from the upper side to the lower side and a plurality of clean gas passages 47 opening to the side. And are formed by being partitioned by a partition wall made of a porous material having air permeability.

On the other hand, as shown in FIG.
On the side where the clean gas flow path of is opened, the clean gas discharge pipe 4
9 is connected to the exhaust pipe 49. Further, the exhaust pipe 49 is provided with a backwash nozzle 51 for injecting compressed gas that opens toward the upstream side of the exhaust gas. The backwash nozzle 51 is connected to the compressed air container 65 via a pipe 67 and a solenoid valve 63. An opening / closing valve 61 is arranged in the discharge pipe 49 downstream of the backwash nozzle 51. This on-off valve 61
Is opened and closed by an air cylinder 70 connected to the compressed air container 65 via a pipe 67 and a solenoid valve 63.

At the lower part of the casing 35, a particulate receiving portion 53 is arranged, and an electric heater 55 for igniting and incinerating the particulates transferred to the particulate receiving portion 53 is provided.

Exhaust gas from the diesel engine passes through an inlet pipe 57 and a casing upper chamber 59 and then passes through a filter 37.
Is introduced into the dust-containing gas passage 39 from the upper open end thereof. Most of the exhaust gas passes through the partition wall of the filter, enters the clean gas flow path 47, and is further discharged through the discharge pipe 49. At this time, the particulates in the exhaust gas are
It cannot pass through the partition walls and adheres to and accumulates on the inner wall surface of the dust-containing gas flow channel 39. After performing such a dust collecting operation for a predetermined time, backwashing is performed for a short time.

When performing the backwashing operation, first the on-off valve 6
1 is closed, the electromagnetic valve 63 is opened after 0 to 1 second, and the compressed air stored in the compressed air container 65 is jetted from the backwash nozzle 51 through the pipe 67 for 0.1 to 1 second, for example. The injected compressed gas becomes a pulse flow, passes from the clean gas flow path 47 of the filter 37 through the partition wall, and flows into the dust-containing gas flow path 39 in the direction opposite to that during the particulate collection operation.

When the backwashing operation is performed by injecting the compressed gas in the opposite direction, the particulates adhering to and depositing on the inner surface of the dust-containing gas passage 39 of the filter 37 are separated from the filter wall surface of the filter 37. Most of the separated particulates fall to the particulate receiving portion 53 provided at the bottom of the casing 35.

In this way, the particulates trapped in the dust-containing gas flow path 39 of the filter 37 in the dust collecting operation are backwashed to the particulate receiving portion 53.
And is ignited and incinerated by the electric heater 55.

As described above, trapping of particulates,
By sequentially performing the backwashing operation and the incineration of the particulates, the particulates in the exhaust gas of the diesel engine can be continuously captured and processed for a long period of time.

[0029]

However, in the above particulate trap for diesel engine, the particulates removed by the backwashing operation are surely ignited by the electric heater arranged at the bottom of the particulate receiving portion. There was a problem that it was not incinerated. That is, when a large amount of particulates is deposited around the electric heater, not only the heat radiation from the heater is hindered, but the particulates cannot be incinerated efficiently,
May be locally overheated due to combustion heat of particulates.

When the electric heater is locally abnormally heated in this way, not only the durability of the heater is deteriorated but also the wire may be broken in a short time. If the electric heater burns out, the amount of particulates remaining in the particulate receiver that is not incinerated increases abnormally, and it becomes impossible to regenerate the filter by backwashing, that is, to remove the particulates. The filter is completely clogged and the diesel engine cannot continue to operate.

Therefore, an object of the present invention is for a diesel engine which can stably and continuously ignite the particulates and incinerate the particulates in the particulate receiving portion and ensure the durability of the electric heater. It is to provide a particulate trap.

[0032]

In order to achieve the above object, a particulate trap for a diesel engine of the present invention comprises a dust-containing gas passage and a clean gas passage defined by a filter wall in an exhaust passage of a diesel engine. A filter having, an introduction pipe for introducing dust-containing gas into the dust-containing gas passage, and an exhaust pipe for discharging clean gas flowing out from the clean-gas passage,
Backwashing means for intermittently generating a gas flow flowing in the opposite direction from the clean gas flow path to the dust-containing gas flow path, and arranged to receive particulates that are washed off from the filter wall of the filter by backwashing In addition, a particulate receiving portion having an electric heater is provided at the bottom, and one or more wire nets or perforated plates are arranged near the upper portion of the electric heater.

In a preferred embodiment of the particulate trap for a diesel engine of the present invention, a cylindrical roller-shaped or spherical solid is placed on the surface of the wire net or the perforated plate. When such solids are placed on the surface of the wire mesh or perforated plate, the solids are placed at various positions on the surface of the wire mesh or perforated plate due to inertial force due to vehicle acceleration / deceleration or centrifugal force when turning a curve. It is possible to disturb the particulates deposited on the surface of the wire mesh or the like and drop them on the electric heater on average.

In another preferred embodiment of the particulate trap for a diesel engine of the present invention, a solid suspended above the wire netting or the perforated plate so as to move like a pendulum just above the wire netted or the perforated plate. Is provided. When this suspended solid is provided, as a result of the weight moving like a pendulum just above the wire netting or the perforated plate, the particulates deposited on the surface of the wire netting or the like are disturbed and the average weight of the electric heater is increased. Can be dropped into.

Furthermore, in still another preferred embodiment of the particulate trap for diesel engine of the present invention,
In the vicinity of the wire netting or the perforated plate, a vibrating means for vibrating the wire netting or the perforated plate by pneumatic drive or electric drive is arranged. By arranging such means, it is possible to disturb the particulates accumulated on the surface of the wire netting or the perforated plate and evenly drop them on the electric heater even when the vehicle is stopped.

[0036]

In the particulate trap for the diesel engine of the present invention, the particulates washed off from the filter wall of the filter by the backwash directly drop and accumulate on the electric heater provided at the bottom of the particulate receiving portion. However, since the particulates are once received by the wire netting or the perforated plate and then fall on the electric heater by the sieving action of the wire netting or the perforated plate, even if the particulates are unevenly deposited on the wire netting or the perforated plate. ,
The electric heater can be shaken evenly.

Further, since the wire netting or the perforated plate has a buffer effect, even if the amount of particulates in the exhaust gas changes with time, the electric heater will have a time-averaged amount of particulates. Can be supplied.

Since a particulate trap for vehicles has a maximum acceleration of about 10 G, it is possible to expect the above-mentioned sieving action without any vibrating means, but it is possible to expect a cylindrical roller-like or spherical solid on a wire mesh or a perforated plate. When the sheet is placed, it rolls randomly due to the movement of the vehicle, so that the particulates temporarily deposited on the wire netting or the perforated plate can be disturbed, and the sieving action can be promoted.

Further, a solid suspended above the wire mesh or the perforated plate so as to move like a pendulum just above the wire mesh or the perforated plate is provided, and the resonance frequency of the suspended solid is the main frequency range of vehicle vibration. When the above condition is satisfied, the solid body vigorously moves, and the above sieving action can be further promoted.

Further, if a vibrating means by air pressure driving or electric driving for vibrating the wire net or the perforated plate is arranged, even in a stationary particulate trap with almost no vibration, appropriate vibration is applied to the wire net or the perforated plate. The above-mentioned sieving action can be secured.

[0041]

1 shows an embodiment of a particulate trap for a diesel engine according to the present invention.

The diesel engine particulate trap 71 is attached to an exhaust pipe for discharging exhaust gas from the diesel engine. That is, in the casing 35 connected to the exhaust pipe via the introduction pipe 57, the filter 37 for trapping particulates is accommodated via the sealing material 38, and the exhaust gas is filtered by the filter 3.
After passing through 7, the gas is discharged from the discharge pipe 49 connected to the clean gas passage side of the filter 37.

A backwash nozzle 51, which is connected to the compressed air container 65 via a pipe 67 and a solenoid valve 63, is arranged in the discharge pipe 49 so as to open toward the upstream side of the exhaust gas. The compressed air container 65 has a pipe 67 different from the above.
And is connected to a compressor (not shown).

The filter 37 is made of cordierite. For example, as shown in FIGS. 10 and 11, a plurality of filter elements 43 made of a porous material are laminated with the ribs 41 and the back surface 45 in contact with each other. , A plurality of dust-containing gas passages 39 penetrating from the upper side to the lower side in the drawing, and a plurality of clean gas passages 47 opening to the side, the partition wall made of a porous material having air permeability. It is formed by being divided by. The rib 41 of the filter element 43 and the back surface 45 are joined by means such as joining with a heat-resistant adhesive, tightening by sandwiching a packing or the like, or joining the filter elements in a laminated state simultaneously with firing. , Airtightness is secured. Instead of providing the ribs 41, the thickness of the adhesive itself may be used, or a space between adjacent filter elements 43 may be secured by sandwiching a band-shaped spacer made of the same material.

A particulate receiving portion 53 is provided below the casing 35. Below the particulate receiving portion 53, as shown in FIG. 1 and FIG.
A wire net 73 is installed. Although the wire net 73 is used in this embodiment, a perforated plate of metal, ceramics or the like may be used instead of the wire net.

The wire mesh 73 is made of stainless steel in this embodiment. The opening of the wire net 73 is 10
0-5.5 mesh, preferably 70-7.5 mesh is good, when using a mesh finer than 100 mesh causes clogging, and when a mesh coarser than 5.5 mesh is used, a buffer action Most of the particulates simply pass through the wire net 73. Further, it is more effective to arrange a plurality of wire meshes in a stacked manner, and it is very effective to arrange a coarse wire mesh in the upper layer and a fine mesh in the lower layer.

It is desirable that the wire net 73 is installed above the electric heater 55 with a distance of 10 mm or more in order to disperse the particulates more uniformly. In addition, when a plurality of wire nets 73 are stacked and installed, it is preferable that the lowermost wire net is located at the above-mentioned position and that the distance between the wire nets is 5 mm or more.

An electric heater 55 for igniting and incinerating particulates is arranged below the metal net 73. In this embodiment, the electric heater 55 has an outer diameter of 6.
5 mm, surface power density 3.0 W / cm ² , power supply 24 V DC U
A letter-shaped seed type electric heater is used, and the surface temperature is set to be in the range of 550 to 700 ° C. in order to ensure the ignition of particulates and ensure the durability of the heater. .. Incidentally. The sheath material of the electric heater 55 is a heat-resistant alloy having corrosion resistance to sulfuric acid components contained in particulates, such as J
It is preferable to use NCF600 or NCF800 of IS.

Further, a combustion air supply nozzle 75 connected to the compressed air container 65 by a pipe 67 is arranged in the particulate receiving portion 53, and the particulate air is supplied even when the residual oxygen concentration in the exhaust gas is low. The burning of the curate is ensured. When the residual oxygen concentration in the exhaust gas is relatively high depending on the engine operating condition, engine type, etc., the supply of air from the combustion air supply nozzle 75 is not always necessary.

On the other hand, an opening / closing valve 61 is arranged in the discharge pipe 49 further downstream than the location where the backwash nozzle 51 is provided. As the on-off valve 61, for example, an exhaust brake butterfly valve used in a diesel engine-driven truck is suitable. The on-off valve 61 is operated by an air cylinder 70 connected to the compressed air container 65 via a pipe 67 and a solenoid valve 68.

Next, a method for trapping and removing particulates in the exhaust gas with this particulate trap will be described.

Exhaust gas from the diesel engine passes through the introduction pipe 57 and the casing upper chamber 59, and then passes through the filter 37.
Into the dust-containing gas passage 39 from the upper open end thereof. The exhaust gas flowing into the dust-containing gas flow path 39 passes through the partition wall of the filter 37, enters the clean gas flow path 47, and is discharged through the discharge pipe 49. At this time, since the particulates in the exhaust gas cannot pass through the partition wall of the filter 37 and adhere to the inner wall surface of the dust-containing gas flow channel 39, the exhaust pipe 49 discharges the particulate-free purified gas. It Such a dust collecting operation is performed for a predetermined time, and a predetermined amount of particulates is attached and deposited on the inner wall surface of the dust-containing gas flow channel 39, and then backwash regeneration is performed for a short time.

When performing the backwashing operation, first, the open / close valve 61 which is in the open state is closed, and t ₁ seconds after that, the solenoid valve 63 is opened for t ₂ seconds, and the backwashing nozzle 51 presses the compressed air. Is ejected for t ₂ seconds. The injected compressed air becomes a pulse flow, and the clean gas flow path 47 of the filter 37.
Flow through the partition wall to the dust-containing gas flow path 39 in the direction opposite to the particulate collection operation, and the dust-containing gas flow path 3
The particulates adhered and accumulated on the inner wall surface of 9 are peeled off. A part of the particulates thus peeled off floats in the dust-containing gas passage 39, but most of the particulates fall to the particulate receiving portion 53 provided at the bottom of the casing 35.

After the ejection of the compressed air is completed, the open / close valve 61 is opened again t ₃ seconds later, and the exhaust gas from the diesel engine is exhausted to the outside of the system through the filter 37 and the exhaust pipe 49.

Normally, a system as shown in FIG. 1 is installed in parallel with respect to the exhaust pipe in accordance with the amount of exhaust gas, and the backwash time of each system is staggered so that a system When backwashing, the exhaust gas from the engine and the compressed gas blown in are exhausted through another system that is not backwashing. By doing so, even when backwashing, only a slight increase in back pressure occurs, and the load on the engine can be reduced.

The series of backwashing operations are restarted after t ₄ seconds, and thereafter such backwashing regeneration cycle is continuously performed during the operation period of the diesel engine.

In the above, the time from t _{1 to} t ₄ is adjusted in each case so that the pressure loss of the filter 37 is maintained below a certain level for a long time, but a series of backwashing is performed. It is preferable that the operation is automatically performed by computer control or the like based on a signal from a sensor that detects a ventilation pressure loss. Note that normally, t
₁ is 0.05 to 3 seconds, preferably 0.05 to 0.5 seconds, t ₂ is 0.02
To 2 seconds, preferably 0.02 to 0.1 seconds, also t ₃ 0.05 to 3
Seconds, preferably about 0.05 to 0.5 seconds.

The particulates collected in the particulate receiving section 53 by the above backwashing operation are deposited on the metal net 73 installed in the particulate receiving section 53. The particulates deposited on the wire net 73 are dropped by an appropriate amount from the mesh of the wire net 73 by the sieving action accompanying the vibration of the vehicle, and are evenly deposited on the electric heater 55. In this way, by tensioning the wire net 73 above the electric heater, even if the particulates fall unevenly on the wire net 73, they can be shaken off evenly with respect to the electric heater 55.

Further, since the particulates peeled off by the backwash once deposit on the wire net 73 and then drop on the electric heater 55, the amount of particulates in the exhaust gas varies with time. However, it is possible to supply the electric heater with a time-averaged amount of particulates.

Next, the particulates are replaced by an electric heater 55.
When the electric heater 55 is evenly deposited on the electric heater 55,
Power up to 400 W to ignite the particulates and incinerate them. At this time, from the combustion air supply nozzle 75, a part of the pressurized air stored in the compressed air container 65 is 0.4 to 4 kg / h, preferably 0.8 to 2 kg / h at the particulate incinerator. Supply continuously or intermittently.

As described above, in the present invention, since the particulates are ignited and incinerated while the particulates are uniformly deposited on the electric heater 55, the electrical heater is locally abnormally heated. This can be prevented and the durability of the heater can be ensured. Further, the unevenly accumulated particulates do not hinder the heat radiation from the heater, and the particulates can be stably incinerated.

FIG. 3 shows another embodiment of the particulate trap for a diesel engine of the present invention.

In this embodiment, a diameter of 3 to 20 is placed on the wire net 73 installed below the particulate receiving portion 53.
A plurality of, for example, 5 mm ceramic balls 77 are mounted. In this embodiment, a ceramic ball that is lightweight and has excellent corrosion resistance and wear resistance is used, but the ball may be made of metal. However, when a metal ball is used, it is preferably lightweight. This is because a lightweight ball has less rolling resistance, can move more freely, and reduces the mechanical load on the wire net 73.

The ceramic balls 77 move to various positions on the wire net 73 by the inertial force due to the acceleration and deceleration of the vehicle, the centrifugal force when turning a curve, and the like.
Disturb the particulates deposited on top. As a result, the sieving action of the wire net 73 can be promoted.

FIG. 4 shows still another embodiment of the particulate trap for the diesel engine of the present invention.

That is, above the wire net 73, a suspended solid 79 for disturbing the particulates deposited on the wire net 73.
Is provided. In this suspension solid 79, a stainless steel ball 81 having a diameter of 20 mm is suspended by a coil spring 83 having a spring constant of 300 N / m and a support metal fitting 85, and the ball 81 is positioned directly above the wire net 73. The natural frequency of the suspended solid 79 is the same as that of the particulate trap 31.
Is set in accordance with the central frequency of the vibration that occurs in the vehicle in which is mounted, and is 15 Hz in this embodiment. It is usually preferable to set the frequency to 5 to 30 Hz.

When the natural frequency of the suspended solid 79 is set in this way, the balls 81 arranged immediately above the wire net 73 vigorously resonate due to the exciting force from the vehicle, and the particulates deposited on the wire net 73 are disturbed. can do.

FIG. 5 shows still another embodiment of the particulate trap for diesel engines of the present invention.

A stirring rod 91 extending from the motor 93 is installed above the wire net 73 in parallel with the wire net 73. The stirring bar 91 has a central portion bent in a convex shape, and is rotated in a direction indicated by an arrow in FIG.
When the convexly bent portion comes closest to the wire net 73, it is positioned directly above the wire net 73. At the same time, a vibrating means 87 is arranged diagonally below the wire net 73, and the tip of a connecting rod 89 extending from the vibrating means 87 is connected to the wire net 73. The connecting rod 89 vibrates the wire net 73 in the direction indicated by the arrow in the figure by the vibrating means 87.

After depositing a predetermined amount of particulates on the wire net 73, the motor 93 and the vibrating means 87 are driven to rotate the stirring rod 91 and vibrate the connecting rod 89 at a frequency of 50 Hz. Then, the rotating stirring rod 91 stirs the particulates,
The wire net 73 vibrates and the sieving action is promoted. In this embodiment, the stirring rod 91 and the connecting rod 89 have their own drive sources, but they may be driven by the same drive source.

By using such means by electric drive, wire mesh can be used even when external force cannot be used as in the case of a stationary particulate trap, or when the vehicle is stopped in a vehicle-mounted particulate trap. The particulates deposited on 73 can be disturbed and dropped on the electric heater on average. It should be noted that in this embodiment, the means by electric driving is used, but the means is not limited to this, and means by pneumatic driving may be used.

[0072]

As described above, in the particulate trap for a diesel engine of the present invention, since the wire mesh or the perforated plate is arranged near the upper portion of the electric heater provided at the bottom of the particulate receiving portion, Particulates that have been washed off from the filter wall of the filter at one time by backwashing are once received by the wire netting or the perforated plate, and then fall onto the electric heater by the sieving action of the wire netted or the perforated plate. Therefore, even if the particulates are nonuniformly deposited on the wire netting or the perforated plate, the particulates can be shaken off evenly with respect to the electric heater, and the particulates can be prevented from being abnormally heated locally. Durability can be secured. Further, the non-uniformly accumulated particulates do not hinder the heat radiation from the heater, and the particulates can be stably incinerated. Further, since the particulates are once received by the wire netting or the perforated plate, and then fall on the electric heater by the sieving action of the wire netting, even if the amount of particulates in the exhaust gas changes with time, The electric heater can be supplied with a time-averaged amount of particulates. Therefore, the incineration process of particulates can be stably continued.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an embodiment of a particulate trap for a diesel engine of the present invention.

FIG. 2 is a side view showing a particulate receiving portion used in the embodiment shown in FIG.

FIG. 3 is a side view showing a particulate receiving portion used in another embodiment of the diesel engine particulate trap of the present invention.

FIG. 4 is a side view showing a particulate receiving portion used in still another embodiment of the particulate trap for a diesel engine of the present invention.

FIG. 5 is a side view showing a particulate receiving portion used in yet another embodiment of the diesel engine particulate trap of the present invention.

FIG. 6 is a perspective view showing an example of a filter that can be used in the diesel engine particulate trap of the present invention.

7 is a cross-sectional view of the filter shown in FIG.

FIG. 8 is a perspective view showing another example of a filter that can be used in the diesel engine particulate trap of the present invention.

FIG. 9 is a side view showing an example of a conventional particulate trap for a diesel engine.

FIG. 10 is a perspective view showing a filter element constituting a filter suitable for the diesel engine particulate trap of the present invention.

11 is a perspective view showing a filter configured by the filter element shown in FIG.

[Explanation of sign]

 1, 11, 37 Filter 35 Casing 39 Dust-containing gas flow path 47 Clean gas flow path 49 Discharge pipe 51 Backwash nozzle 53 Particulate receiving part 55 Electric heater 57 Introducing pipe 61 Open / close valve 63 Electromagnetic valve 65 Compressed air container 67 Piping 71 Particulate trap 73 Wire mesh 75 Combustion air supply nozzle 77 Ceramics ball 79 Suspended solid 81 Ball 83 Coil spring 85 Support fitting 87 Vibrating means 89 Connecting rod 91 Stirring rod 93 Motor

[Procedure amendment]

[Submission date] May 18, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Description of marks No.] 1,11,37 filter 35 casing 39 dust-containing gas flow passage 47 clean gas passages 49 exhaust pipe 51 backwashing nozzle 53 particulate receiving part 55 an electric heater 57 inlet 61 on-off valve 63 solenoid valve 65 Compressed air container 67 Piping 71 Particulate trap 73 Wire mesh 75 Combustion air supply nozzle 77 Ceramic ball 79 Suspended solid 81 Ball 83 Coil spring 85 Support metal fitting 87 Vibrating means 89 Connecting rod 91 Stirring rod 93 Motor ───────── ─────────────────────────────────────────────

[Procedure amendment]

[Submission date] July 22, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Description of marks No.] 1,11,37 filter 35 casing 39 dust-containing gas flow passage 47 clean gas passages 49 exhaust pipe 51 backwashing nozzle 53 particulate receiving part 55 an electric heater 57 inlet 61 on-off valve 63 solenoid valve 65 Compressed air container 67 Piping 71 Particulate trap 73 Wire mesh 75 Combustion air supply nozzle 77 Ceramics ball 79 Suspended solid 81 Ball 83 Coil spring 85 Support metal fitting 87 Vibrating means 89 Connecting rod 91 Stirring rod 93 Motor

Claims (4)

[Claims] 1. A filter having, in an exhaust passage of a diesel engine, a dust-containing gas passage and a clean gas passage, which are partitioned by a filter wall, and an introduction pipe for introducing dust-containing gas into the dust-containing gas passage. An exhaust pipe for discharging the clean gas flowing out from the clean gas passage, a backwashing means for intermittently generating a gas flow flowing in the opposite direction from the clean gas passage to the dust-containing gas passage, and Arranged to receive the particulates washed off from the filter wall of the filter by washing, a particulate receiving portion having an electric heater at the bottom is provided, and one or more wire nets or perforated plates are provided near the electric heater. A particulate trap for diesel engines characterized by being placed. 2. The particulate trap for a diesel engine according to claim 1, wherein a cylindrical roller-shaped or spherical solid is placed on the surface of the wire mesh or the porous plate. 3. The particulate trap for a diesel engine according to claim 1, wherein a solid suspended above the metal net or the perforated plate so as to move like a pendulum just above the metal net or the perforated plate is provided. 4. The particulate trap for a diesel engine according to claim 1, wherein a vibrating means for vibrating the metal net or the perforated plate is provided near the metal net or the perforated plate by a pneumatic drive or an electric drive.