JPH0730312U - Particulate trap - Google Patents

Abstract

(57) [Summary] [Objective] The present invention relates to a particulate trap for purifying engine exhaust gas, which is easy to replace, withstands high gas pressure, and prevents cracks in the outer periphery and local differences in regeneration effect. The purpose is to do. [Composition] A can body having an exhaust gas inflow / outflow port, a trap filter having an exhaust gas inflow / outflow surface housed between the inflow / outflow port in the can body, and an inner wall of the can body and a trap filter. In a particulate trap that is placed between the inlet and outlet sides of the trap filter and a heater wire that surrounds the outer circumference, the trap filter is fixed in the inner case that is housed between the inlet and outlet of the can. The inner case covers the portion other than the inflow / outflow surface of the trap / filter, and the flanges at the inflow-side end and the outflow-side end have gaskets on the flanges at the opposite positions of the can body, respectively. Bolted through.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure of a particulate trap for purifying exhaust gas from an engine of an automobile or the like.

A particulate trap is used to adsorb and collect particulate matter such as carbon particles contained in the exhaust gas of an engine to purify the exhaust gas before discharging it. It means "particulate matter collection device" when it is translated into Japanese.

[0003] The particulate trap requires a work of regenerating, that is, removing the collected particulate matter after running and using it, and thus there have been various problems in the conventional structure.

[0004]

[Prior art]

 As examples of disclosure regarding the structure of the particulate trap, there are Japanese Patent Laid-Open No. 59-153913, Japanese Utility Model Laid-Open No. 2-118121, and Japanese Utility Model Laid-Open No. 4-21717.

FIG. 3 shows a cross-sectional view of a prior art particulate trap. In the figure, C is the main body of the particulate trap, that is, the can body. The can body C is usually made of a metal having a cylindrical or elliptic cylinder shape, is equipped with an exhaust gas inlet a and an exhaust gas outlet b, and is provided with an exhaust gas upstream side and a downstream side via a flange A and a flange B, respectively. Side exhaust passage. FIG. 3 is a sectional view of the case where the particulate trap is cut along a vertical plane passing through the axis of the can body C.

In the figure, 1 is a trap filter (filter for collection), 2 is a heater wire (heating wire), 3 is a heat insulating material for holding a heater, 4 is a heat insulating material, 5 is a heater terminal, 6 is a A temperature sensor 13 is a diffuser (diffuser) portion of the can body C.

The operation of the conventional particulate trap will be described below. There are two aspects to the operation of a particulate trap. The first is a particulate matter collection operation, and the second is a regeneration operation.

First, the first particulate matter trapping operation is an essential operation of the particulate trap that is mainly performed during traveling. In FIG. 3, the exhaust gas that has flowed in from the exhaust gas inlet a flows in from the exhaust gas inlet surface of the trap filter 1 near the exhaust gas inlet a, and the carbon fine particles and the like mixed therein. Particulate matter is adsorbed. Then, the purified exhaust gas is exhausted into the atmosphere via the exhaust gas outflow surface of the trap filter 1 near the exhaust gas outlet b and the exhaust gas outlet b.

The large number of horizontal lines shown in the trap filter 1 is a set of thin walls (hereinafter, the space formed by the enclosed walls is called a cell). FIG. 4 is an enlarged cross-sectional view assuming that one of the cells is cut along a plane passing through its axis. The material of the wall is a porous ceramic, which is composed of the pore wall E, the cell mouth e, and the plugging material F as shown in the drawing, and the pore wall E has numerous capillary pores open. , Penetrates from inside the cell to outside the cell. Therefore, the exhaust gas flowing in from the cell port e follows the path shown by the arrow in the figure and permeates through numerous pores and is discharged. At this time, the particulate matter mixed in the exhaust gas flows through the pores. It cannot pass and is adsorbed here. In the set of the filter cells in FIG. 3, the cell openings e of the adjacent filter cells and the plugging material F are arranged alternately.

Next, the second regeneration operation is an auxiliary operation of the particulate trap that is mainly performed in the garage after traveling. That is, the pores are filled with adsorbed particulate matter due to the particulate matter trapping operation performed during traveling, and if the pores are continuously used without any treatment, the pores are blocked by the particulate matter and the exhaust gas is exhausted. Spillage becomes difficult and unusable. Therefore, it is necessary to remove the particulate matter adsorbed by the trap filter and treat the particulate trap after the particulate matter trapping operation so that the particulate trap can be used with good performance. This treatment is reproduction, and the operation for reproduction is reproduction operation.

The reproducing operation is usually performed by connecting a power source outside the automobile to the heater terminal 5 in FIG. 3 and supplying a heating current to the heater wire 2. As shown in the figure, the heater wire 2 is arranged so as to be extremely close to or in contact with the outer periphery of the trap filter 1, and is fixed by a heater holding heat insulating material 3. The temperature of the heater can be detected by the temperature sensor 6, and the inner wall of the can body C is covered with the heat insulating material 4 so that the exhaust gas and the heat of the heater are not conducted to the outside of the can body C.

By heating the trap filter 1 with the heater wire 2, the particulate matter is burned, vaporized and removed. At this time, the heating temperature is slowly increased, and in this case, the amount of auxiliary combustion air (air supplied for combustion) flowing through the exhaust gas inflow / outflow ports a and b is limited to perform gentle combustion. This is an essential condition for obtaining high-performance playback operation.

[0013]

[Problems to be solved by the device]

 However, according to the conventional technique as described above, "it is not easy to replace the trap filter", and the trap filter is exposed to high-pressure exhaust gas, so that "holding and fixing to withstand high exhaust gas pressure is difficult. In addition, since the trap filter is heated directly from the outer circumference by the heater wire, "a local temperature difference occurs in the outer circumference", and therefore "fine cracks occur due to this temperature difference". In addition, there were problems such as “there is a local difference in the regeneration effect due to this temperature difference”.

Therefore, the object of the present invention is, except for the above-mentioned drawbacks of the prior art, that the trap filter is easy to replace, it can withstand high pressure well, and fine cracks occur in the outer periphery. The point is to provide a particulate trap that does not cause local differences in regeneration effect.

[0015]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has the following configuration. That is, a can body having an inflow port and an outflow port for exhaust gas, and a trap filter housed in a portion between the inflow port and the outflow port in the can body and having an inflow surface and an outflow surface for exhaust gas. A particulate trap that is arranged between the inner wall of the can body and the trap filter and that comprises a heater wire surrounding the outer periphery of the trap filter excluding the inflow surface and the outflow surface, The trap filter is fixed in an inner case (inner housing) housed in a portion between the inflow port and the outflow port in the can body, and the inner case is the inflow surface of the trap filter. And flanges formed on the inflow-side end and the outflow-side end that cover portions other than the outflow surface and the outflow surface. Each is bolted through the gasket (Gasket = sealing packing).

[0016]

[Action]

 First, for the first particulate matter collecting operation, since the trap filter is fixed inside the inner casing (inner housing), the trap filter is held and fixed while enduring a high exhaust gas pressure. Also, since the flanges on both ends of the inner case and the flange of the can body are bolted through gaskets (Gasket = sealing packing), exhaust gas does not leak from the can body.

Next, for the second regeneration operation, since the trap filter is indirectly heated through the wall of the inner case, a local temperature difference occurs in the outer peripheral portion of the trap filter. As a result, fine cracks do not occur and local differences in the regeneration effect do not occur. Also, since the flanges on both ends of the inner case and the flange of the can body are bolted together via a gasket, the trap / filter can be easily replaced with the inner case in one place by operating the bolts.

[0018]

【Example】

 FIG. 1 is a partial sectional view showing the structure of an embodiment of the particulate trap of the present invention. In the figure, D is a can body, and the can body D is usually made of a metal having a cylindrical or elliptic cylinder shape, and is provided with an exhaust gas inflow port a and an exhaust gas outflow port b, and a flange A and a flange B respectively. It is the same as the prior art in that it is connected to the exhaust passages on the upstream side and the downstream side of the exhaust gas flow, respectively. Fig. 1 is a side view showing the appearance of the particulate trap above the horizontal plane passing through the axis of the can body D, and the bottom portion is passing through the axis of the can body D. It is a cross-sectional view when it is assumed that the lower half of the particulate trap is cut by a vertical plane.

In the figure, 1 is a trap filter, 2 is a heater wire, 3 is a heat insulating material for holding a heater made of asbestos (asbestos), 4 is a heat insulating material made of the same asbestos, 5 is a heater terminal, 6 Is a temperature sensor, and 13 is a diffuser portion of the can body D.

As new parts, 7 is an inner case, 8 is a heater chamber, 9 is a wire mesh (metal mesh), 10 is a fixed flange, 11 is a removable flange, and 12 is an asbestos gasket.

As shown, the trap filter 1 is fixed in the inner case 7, and the heater wire 2 is held in the heater chamber 8. Since the trap filter 1 is fixed inside the inner case 7, the trap filter 1 is mechanically firmly held even when exposed to a high exhaust gas pressure. In order to make the temperature distribution of the outer periphery of the trap filter 1 more uniform and at the same time mechanically protect the outer periphery, in this embodiment, between the trap filter 1 and the inner wall of the inner case 7, heat conductivity and cushioning property are provided. Good wire mesh 9 is inserted. Further, since the heater wire 2 is held and fixed in the heater chamber 8 close to the inner case 7, and the heat generated in the heater wire 2 does not reach the can body D, the heater holding in the heater chamber 8 is performed. The heat insulating material 3 is filled. Since the heater chamber 8 is completely covered with a wall and is isolated from the exhaust flow, the particulate matter in the exhaust gas does not adhere to the heater wire 2 to cause electric leakage or short circuit. Further, the inner wall of the can body D is covered with the heat insulating material 4, so that the exhaust gas and the heat of the heater are not conducted to the can body D.

On the other hand, a flange is formed at the end of the inner case 7 on the exhaust gas inlet a side and the end of the exhaust gas outlet b on the side of the can body D and the diffuser portion 13 of the can body D. Flange is also formed at the corresponding position. Further, since the flange of the inner case 7 and the flange of the can body D and the diffuser portion 13 of the can body D are bolted through the gasket, it is difficult to regenerate the trap filter or there is a time margin to regenerate it. If you want to use a trap filter that has already been regenerated, you can easily replace the trap filter with the inner casing in one place by removing and tightening the bolts. Moreover, since bolting is done through the gasket, the exhaust gas does not leak from the can body D after tightening.

In this embodiment, a fixed flange 10 is applied to the end of the inner case 7 on the exhaust gas inlet a side, and a removable flange 11 is applied to the end of the inner gas 7 on the exhaust gas outlet b side. It is screwed through 12. Therefore, when replacing the trap filter 1, first remove the diffuser portion 13 of the can body D, and then remove the bolts 14 of the detachable flange 11 so that the inner case 7 and the left side of the can body D can be located in one place. Can be extracted.

As shown in FIG. 2, after the diffuser portion 13 is removed as described above, the trap filter 1 fixed to the inner case 7 is pulled out from the can body D to the left side of the can body D in one place with the inner case 7. FIG. 6 is a partial cross-sectional view schematically showing the state of each separated member on the way. The method of creating this partial cross-sectional view is exactly the same as in the case of FIG.

[0025]

[Effect of device]

 As described above, according to the present invention, the trap filter is firmly held against the high exhaust gas pressure, is easy to replace, and the exhaust gas does not leak from the can body. It is possible to realize a particulate trap that does not cause fine cracks on the inside or local differences in the regeneration effect.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a trap filter as it is extracted.

FIG. 3 is a sectional view of a conventional particulate trap.

FIG. 4 is a cross-sectional view of a filter capillary.

[Explanation of symbols]

 1 Trap / Filter 2 Heater Wire 3 Heat Insulation Material for Holding Heater 4 Heat Insulation Material 5 Heater Terminal 6 Temperature Sensor 7 Inner Case 8 Heater Chamber 9 Wire Mesh 10 Fixed Flange 11 Detachable Flange 12 Gasket 13 Diffuser Part 14 Bolt

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Tadashi Ishii 1-chome, Ichome, Ageo City, Saitama Prefecture Nissan Diesel Industry Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A trap having a can body having an exhaust gas inlet and an outlet, and a trap housed in a portion of the can body between the inlet and the outlet and having an exhaust gas inflow surface and an outflow surface. A particulate trap comprising a filter and a heater wire disposed between the inner wall of the can body and the trap filter and surrounding the outer periphery of the trap filter excluding the inflow surface and the outflow surface. The trap filter is fixed in an inner case housed in a portion of the can between the inlet and the outlet, and the inner case is a portion other than the inflow surface and the outflow surface of the trap filter. And the flanges formed on the inlet side end and the outlet side end are covered with gaskets respectively. Particulate trap, characterized in that bolted through.