JPH0587216U - Particulate trap device - Google Patents

Abstract

(57) [Summary] [Purpose] Prevents cracking of the filter. [Structure] The length of the heat insulating material in the axial direction is made shorter than that of the filter, and a portion having no heat insulating material is formed on the upstream side of the filter.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a particulate trap device which has a casing on the outer circumference thereof, holds a trap filter through a heat insulating material, and heats the trap filter by a heating means for regeneration.

[0002]

[Prior Art]

 In diesel engines, in order to remove and clean the particulates (carbon particulates) contained in the exhaust, a particulate trap filter is installed in the exhaust passage and the filter is clogged upstream. A particulate trap device is known in which a burner is provided as an auxiliary combustion device that operates according to the above conditions, and the particulate matter collected by the trap filter is re-combusted by the combustion gas from the burner (actually developed. 58-180711, etc.).

An example of this will be described with reference to FIGS. 4 and 5. The trap filter 1 is held in the casing 3a via a cushioning and heat insulating material 4a, and the burner 5 is provided so as to face the filter 1. ing. Then, the length of the heat insulating material 4a in the axial direction is formed to be the same as the length of the filter 1 in the axial direction.

[0004]

[Problems to be solved by the device]

 In the above particulate trap device, when the trap filter 1 is rapidly heated and regenerated by the burner 5, the temperature of the central portion B becomes higher than the temperatures of the outer peripheral portions A and C as shown in the characteristic b of FIG. A large temperature difference occurs. Therefore, tensile thermal stress is generated in the outer peripheral portions A and C of the trap filter 1, and as shown in FIG. 6, the front outer edge portion D of the filter 1 is used as a starting point, and the filter center portion and the filter outer peripheral surface are formed. Extending cracks K1 and K2 occur.

An object of the present invention is to provide a particulate trap device that prevents cracks in a trap filter.

[0006]

[Means for Solving the Problems]

 According to the present invention, in the particulate trap device, which comprises a casing on the outer periphery, holds the trap filter through the heat insulating material, and heats the trap filter by the heating means for regeneration, the length of the heat insulating material in the axial direction is increased. Is formed to be shorter than the axial length of the trap filter, and a portion without the heat insulating material is formed on the upstream side of the trap filter.

The length of the portion without the heat insulating material is preferably 5 to 20% of the length of the trap filter in the axial direction. If it is 5% or less, the heating of the outer peripheral portion is insufficient, and the temperature difference between the central portions is insufficiently reduced, and if it is 20% or more, the support of the trap filter by the heat insulating material becomes unstable. Because it will be. The heating means is preferably composed of a burner, an electric heater, an intake throttle device, an exhaust throttle device and the like.

[0008]

[Action]

 In the particulate trap device configured as described above, the heat of the burner directly heats the part without the heat insulating material between the trap filter and the casing. The part is heated. Therefore, the thermal expansion of the front part of the trap filter is made uniform, and cracks due to tensile stress are prevented.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, an exhaust passage 2 of the engine is provided with a particulate trap device generally designated by T. The filter trap 1 is fixed in the casing 3 via a cushioning / insulating material 4. On the upstream axis of the filter 1, an opening 5a of a burner 5 that is a heating means is provided. The burner 5 is connected to a control unit 9, and various sensors (not shown) are connected to the unit 9.

The length L 1 of the heat insulating material 4 in the axial direction is shorter than the length L 1 of the filter 1 in the axial direction. A portion E having the length L2 and having no heat insulating material 4 is formed on the upstream side of the filter 1. The length L2 of the portion E is 5 to 20% of the length L.

Next, the operation will be described.

When the control unit 9 determines based on the detection signals from the various sensors that the re-burning process of the trapped particulates is necessary, the burner 5 is activated to start regeneration. At the time of regeneration, the heat of the burner 5 directly heats the portion E between the filter 1 and the casing 3 where the heat insulating material 4 is not provided, so that the outer peripheral portions A and C, which are conventionally not heated compared to the central portion B, are heated. To be done. Therefore, as indicated by the characteristic a in FIG. 3, the temperature difference in the front part of the filter 1 is reduced and the thermal expansion is made uniform. As a result, cracks K1 and K2 (FIG. 6) due to tensile stress are prevented. If the length L2 of the portion E is 5% or less of the length of the filter 1, heating of the outer peripheral portion is insufficient and no effect is obtained, and if it is 20% or more, the support of the filter 1 by the heat insulating material 4 is not achieved. Insufficiently, the filter 1 vibrates when the vehicle is running and may cause damage, which is not preferable.

[0014]

[Effect of the device]

 Since the present invention is configured as described above, it is possible to reduce the temperature difference between the central portion and the outer peripheral portion of the filter that occurs when the filter is heated, and prevent the filter from cracking.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a temperature difference characteristic diagram showing the effect.

FIG. 4 is a side sectional view showing a conventional device.

5 is an enlarged view of a main part of FIG.

FIG. 6 is a perspective view illustrating a crack that has occurred.

[Explanation of symbols]

 B ... Central part A, C ... Peripheral part D ... Starting point E ... Part without heat insulating material K1, K2 ... Crack T ... Particulate trap device 1 ... Trap filter 2 ... Exhaust passage 3, 3a ... Casing 4, 4a ... Buffer and heat insulating material 5 ... Burner 5a ... Opening 9 ... Control unit

Claims (1)

[Scope of utility model registration request] 1. A particulate trap device, comprising a casing on the outer periphery thereof, holding a trap filter through a heat insulating material, and heating the trap filter by a heating means for regeneration, wherein the heat insulating material has a length in the axial direction. Formed shorter than the axial length of the trap filter,
A particulate trap device characterized in that a portion without the heat insulating material is formed on the upstream side of the trap filter.