JPH062528A - Adiabatic diesel particulate filter device - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to an adiabatic diesel particulate filter device for removing particulate solids (particulates) such as black smoke in the exhaust of a diesel engine,
The purpose is to increase the regeneration rate of the filter and also shorten the preheating time. In a diesel particulate filter device interposed in an exhaust gas passage EX of a diesel engine, a filter 7 for collecting particulates in exhaust gas, a case C for housing the filter 7, and a filter 7 are provided. A heat insulating material 13 provided with a particulate combustion means B for burning the collected particulates and for insulating the filter 7 from the exhaust gas passage outside the passage of the filter 7 in the radial direction of the passage when the particulates burn.
It is configured to be installed around.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adiabatic diesel particulate filter device equipped to remove particulate solid matter (particulates) such as black smoke in an exhaust system of a diesel engine.

[0002]

2. Description of the Related Art Conventionally, it has been considered to equip a diesel engine exhaust system with a diesel particulate filter device in order to remove particulate solid matter (particulates) such as black smoke. The conventional diesel particulate filter device is configured as shown in FIGS. 2 to 5. FIG. 2 is a schematic side view showing a partial cutaway of a main part of the diesel particulate filter device, and FIG. FIG. 4 is a schematic block diagram showing an example, FIG. 4 is a schematic block diagram showing another example of the equipment state, and FIG. 5 is a graph showing the particulate combustion regeneration operation.

As shown in FIGS. 2 to 4, in the diesel particulate filter device S interposed in the exhaust gas passage EX of the diesel engine, the front case 1,
The case 7 formed by the center case 8 and the rear case 11 has a filter 7 built therein for collecting particulates in the exhaust gas. The front case 1 and the center case 8 and the center case 8 and the rear case 11 are fixed to each other with bolts 5 and 10 via gaskets 4 and 9, respectively. Through the inside, rear case 11
Extends to the upstream end of.

The filter 7 has a supporter mesh 6 wound around the outer circumference in the passage radial direction, and is supported by the case C in the passage radial direction via the supporter mesh 6.
The filter 7 is fitted into the center case 8 from the upstream side, and the flange portion 8 at the downstream end of the center case 8 is inserted.
It is sandwiched by A and the plate 3 ′ of the front case 1 in the passage axial direction.

The filter 7 is formed of a carrier such as cordierite, and in the case C on the upstream side of the filter 7,
Particulate burning means B is provided to burn the particulates collected by the filter 7 when required. The particulate combustion means B is composed of the heater 2 and the secondary air supply passage 17.

That is, the heater 2 is provided so as to face the upstream end of the filter 7, and the required current is supplied from the power source at a predetermined time to drive the filter 7 to, for example, 500 ° C.
It is configured so that it can be heated to a certain degree. The secondary air supply passage 17 is laterally connected to the upstream end portion of the front case 1, and the combustion air is supplied at a predetermined timing by the secondary air supply passage 17. ing.

Heating by heater 2 and secondary air supply path 17
The supply of combustion air by means of is performed according to the characteristics shown in the time chart of FIG. That is, when the particulate accumulation amount in the filter 7 reaches a predetermined state, the inflow of exhaust gas into the filter device S is blocked, and then the heater 2 is turned on from the time T0 to perform the preheating by the heater 2.

As a result, the temperature of the filter 7 is 500 °
It rises toward C, but at time T1, the filter 7
When the temperature reaches 500 ° C, the secondary air supply from the secondary air supply passage 17 is started, the particulate combustion in the filter 7 is started, and the combustion is sequentially performed from the upstream side to the downstream side of the filter 7. Propagate. After the combustion is started, afterheat by the heater 2 is performed at time T so that the entire particulates of the filter 7 are burned.
After 2 hours, the heater 2 is turned off at time T2.

Secondary air is supplied from the secondary air supply passage 17 until the particulates in the filter 7 are completely burned. If the secondary air is cut off at time T3, the particulates are burned. The sequence is completed from the upstream side. As a result, the particulates adhering to the filter 7 are almost completely removed, the filter 7 is regenerated to a state in which it is not trapped, and the temperature gradually drops.

It is considered to equip the diesel particulate filter device S which performs such an operation in the state shown in FIGS. 3 and 4, for example. In the structure shown in FIG. 3, a pair of diesel particulate filter devices S
1, S2 are provided in parallel with the exhaust gas passage EX. A valve V1 is provided at the upstream branch of the diesel particulate filter devices S1 and S2. Further, although the downstream sides of the diesel particulate filter devices S1 and S2 are merged, the downstream sides may not be merged, and the exhaust may be performed independently.

The valve V1 is a switching valve constructed so that one of the filter devices S1 and S2 is opened and the other is closed, and the operation of the valve V1 enables either of the diesel particulate filter devices S1 and S2 to be operated. The exhaust passage can be selectively formed through one of them. The switching of the valve V1 is performed every time one of the diesel particulate filter devices S1 and S2 is performing the trapping operation, and the valve V1 is closed to perform the trapping operation. On the other side, the filter 7 is regenerated by burning the accumulated particulates.

Further, in the structure shown in FIG. 4, the diesel particulate filter device S is provided with the bypass P via the valve V1, and the valve V1 is switched during combustion regeneration of the filter 7 in the diesel particulate filter device S. The exhaust gas is circulated through the bypass P.

[0013]

By the way, in such a conventional diesel particulate filter device S, when the filter 7 is regenerated, heat is dissipated to the outside in the radial direction of the passage, so that the temperature at the outer peripheral portion of the filter 7 is increased. However, there is a problem that the regeneration rate becomes low because the regeneration rate becomes insufficient and the regeneration rate becomes uncertain.

This phenomenon is also caused by the fact that the amount of particulates trapped on the outer peripheral portion of the filter 7 is small, so that there are few targets for combustion and the combustion temperature does not rise sufficiently. There is also a problem that the temperature of the filter 7 is hard to rise due to heat radiation from the diesel particulate filter device S and the preheating time increases.

The present invention has been devised in view of the above problems, and it is an adiabatic diesel particulate filter that can improve the regeneration rate of the filter in the diesel particulate filter device and shorten the preheating time. The purpose is to provide a device.

[0016]

Therefore, the adiabatic diesel particulate filter device of the present invention according to claim 1 is a diesel particulate filter device installed in an exhaust gas passage of a diesel engine, wherein:
A filter that collects particulates in the exhaust gas,
The filter is provided with a case for accommodating the filter and a particulate combustion means for burning the particulate collected by the filter, and the filter is exhausted to the outside in the radial direction of the passage of the filter when the particulate is burned. It is characterized in that a heat insulating material for insulating the gas passage is provided around the gas passage.

It is preferable that the heat insulating material is provided at a predetermined distance from the outer periphery of the filter. Moreover, as described in claim 3,
When the outer case is provided so as to cover the heat insulating material, a supporting member capable of absorbing a difference in thermal expansion between the outer case and the heat insulating material is interposed between the outer case and the heat insulating material. Is desirable.

[0018]

In the adiabatic diesel particulate filter device of the present invention as set forth in claim 1, when the particulate matter collected by the filter is burned by the combustion means, the heat insulating material prevents heat radiation from the case, The filter is kept at a high temperature and efficient filter regeneration is performed.

Further, as described in claim 2, by providing the heat insulating material with a predetermined distance from the outer periphery of the filter, the difference in shape between the heat insulating material and the filter due to thermal expansion is absorbed. Further, when the outer case is provided so as to cover the heat insulating material as described in claim 3, a difference in thermal expansion between the outer case and the heat insulating material is absorbed between the outer case and the heat insulating material. The heat insulating material is supported while the thermal expansion difference between the outer case and the heat insulating material is absorbed by interposing a support member that can be used.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An adiabatic diesel particulate filter device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view showing a main portion partially broken. Many parts of the adiabatic diesel particulate filter device of the present embodiment are constructed in substantially the same manner as the conventional structure shown in FIGS. 2 to 5, and the same reference numerals indicate substantially the same components.

In the present embodiment, the filter 7 is fitted and inserted into the cylindrical inner case 12 with the outer periphery thereof being covered with the supporter mesh 6. Inner case 12
Has a claw-shaped inner case supporter 3 on its upstream outer periphery.
The inner case 12 is fixed by tightening the inner case supporter 3 together with the gasket 4 when tightening the front case 1 and the center case 8 with the bolt 5. .

A heat insulating material 13 is provided outside the inner case 12 in the radial direction of the passage in a predetermined spaced state with an air layer 18 interposed therebetween. The heat insulating material 13 is made of ceramic or the like, and is a filter. 7 can be insulated from the outside of the diesel particulate filter device S. The heat insulating material 13 is surrounded by a heat insulating supporter mesh 16 formed of a heat insulating material, and is supported by the center case 8 via the heat insulating supporter mesh 16.

The filter 7 is fixed to the rear case 11 by tightening the downstream end thereof with a bolt 15 through the filter fixing plate 14. Further, as described above, the front case 1, the center case 8 and the center case 8 are
The rear case 11 and the rear case 11 are fixed to each other with bolts 5 and 10 via gaskets 4 and 9, respectively, to form a case C. However, since the inner case 12 is provided in this device, the case C is an outer case. Also called.

Since the adiabatic diesel particulate filter device as one embodiment of the present invention is constructed as described above, in the construction shown in FIG. 3 or FIG.
The particulate trapping operation and the regeneration operation of the filter 7 by burning the particulates are alternately performed at a predetermined timing according to the characteristics shown in FIG. And
When the particulates are burned, the heat insulating material 13 insulates the filter 7 in the radial direction of the passage, so that the heater 2 efficiently heats the heat and the heat is transferred to the outer periphery of the filter 7.

As a result, the particulates are evenly burned up to the outer periphery of the filter 7, where the amount of trapped particles is small and the combustion temperature may not rise, and the regeneration rate of the filter 7 is improved. Further, since the heating from the heater 2 is efficiently performed, sufficient combustion is performed with a short preheat.

Therefore, the regeneration time of the filter 7 is shortened, and particularly in the structure shown in FIG. 4, the collection operation time length by the diesel particulate filter device S is relatively increased, and the exhaust particulate concentration can be reduced. Become. By the way, since the heat insulating material 13 is made of ceramic or the like, the front case 1 and the center case 8 are
And a deformation difference due to thermal expansion occurs, but this deformation difference is absorbed by the heat insulating supporter mesh 16.

Further, a deformation difference due to thermal expansion also occurs between the heat insulating material 13 and the inner case 12, and this deformation difference is caused by the air layer 18 between the heat insulating material 13 and the inner case 12.
Absorbed by. This avoids damage to the heat insulating material 13 during the combustion operation. The difference in thermal expansion between the filter 7 and the inner case 12 is absorbed by the supporter mesh 6.

Further, the shape of the case C and the structure around the filter 7 and the heat insulating material 13 are not limited to this, and the filter 7 which burns when the heat insulating material 13 is provided is installed.
Various forms are conceivable if the can be insulated.

[0029]

As described in detail above, according to the adiabatic diesel particulate filter device of the present invention as set forth in claim 1, in the diesel particulate filter device provided in the exhaust gas passage of the diesel engine, the exhaust gas is exhausted. A filter for collecting particulates in the gas, a case for housing the filter, and a particulate combustion means for burning the particulates collected by the filter are provided in the passage radial direction outward of the filter. With a simple structure in which a heat insulating material that insulates the filter from the outside of the exhaust gas passage during the combustion of the particulates is provided around the exhaust gas passage, the regeneration rate of the filter can be increased and the preheating time can be shortened. There is.

Further, as described in claim 2, by providing the heat insulating material in a predetermined distance from the outer periphery of the filter, the heat insulating material is provided against the difference in thermal expansion between the heat insulating material and the filter. It has the advantage that it can be equipped to prevent damage.
Further, when the outer case is provided so as to cover the heat insulating material as described in claim 3, a difference in thermal expansion between the outer case and the heat insulating material is absorbed between the outer case and the heat insulating material. There is an advantage that the heat insulating material can be provided so as not to be damaged by the difference in thermal expansion between the outer case and the heat insulating material by interposing the flexible supporting member.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an adiabatic diesel particulate filter device of the present invention with a part of its main part cut away.

FIG. 2 is a schematic side view showing a conventional diesel particulate filter device with a main part partially broken away.

FIG. 3 is a schematic configuration diagram showing an example of an installed state of a conventional diesel particulate filter device.

FIG. 4 is a schematic configuration diagram showing another example of the state of equipment of a conventional diesel particulate filter device.

FIG. 5 is a time chart and a graph showing a particulate combustion regeneration operation of a conventional diesel particulate filter device.

[Explanation of symbols]

1 Front Case 2 Heater 3 Inner Case Supporter 3'Plate 4 Gasket 5 Bolt 6 Supporter Mesh 7 Filter 8 Center Case 8A Flange 9 Gasket 10 Bolt 11 Rear Case 12 Inner Case 13 Heat Insulation Material 14 Filter Fixing Plate 15 Bolt 16 Heat Insulator Support Mesh 17 Secondary air supply path 18 Air layer B Particulate combustion means C Case (outer case) EX Exhaust gas path P Bypass S, S1, S2 Diesel particulate filter device V1 valve

Claims (3)

[Claims] 1. A diesel particulate filter device interposed in an exhaust gas passage of a diesel engine, a filter for collecting particulates in the exhaust gas, a case for housing the filter, and the filter for collecting the particulates. A particulate combustion means for burning the particulates is provided, and a heat insulating material for thermally insulating the filter from the outside of the exhaust gas passage at the time of burning the particulates is provided outside in the radial direction of the passage of the filter. An adiabatic diesel particulate filter device characterized in that 2. The adiabatic diesel particulate filter device according to claim 1, wherein the heat insulating material is provided in a predetermined distance from the outer periphery of the filter. 3. An outer case is provided so as to cover the heat insulating material, and a support member capable of absorbing a difference in thermal expansion between the outer case and the heat insulating material is provided between the outer case and the heat insulating material. The adiabatic diesel particulate filter device according to claim 1, wherein the adiabatic diesel particulate filter device is provided.