JPH0730313U - Particulate trap - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a particulate trap for purifying engine exhaust gas, and it is an object of the present invention to prevent the occurrence of cracks or the like in the outer peripheral portion of the trap filter. [Constitution] A can body having an exhaust gas inlet and an outlet,
A trap filter that is housed between an inlet and an outlet in the can and has an exhaust gas inflow surface and an outflow surface, and a trap filter that is placed between the inner wall of the can and the trap filter.
In a particulate trap composed of a heater wire surrounding the outer periphery of the filter excluding the inflow surface and the outflow surface, the trap filter is housed in the portion between the inflow port and the outflow port in the can, and the trap filter Of the electrically insulating material that is fixed inside the inner case that covers the outer circumference of the inner case except for the inflow surface and the outflow surface and that has a good thermal conductivity in the gap between the heater wire and the portion surrounding the heater wire on the outer circumference of the inner case. Fill with a layer made of.

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. 2 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. 2 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. 2, the exhaust gas flowing in from the exhaust gas inlet a flows in from the exhaust gas inlet surface of the trap filter 1 on the side 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. 3 is an enlarged cross-sectional view on the assumption 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 a pore wall E, a cell opening e, and a plugging material F as shown in the figure, 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 is the pores. Cannot pass through and is adsorbed here. In the set of the filter cells shown in FIG. 2, 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. 2 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, the gap between the heater wire 2 and the portion on the outer periphery of the trap filter 1 surrounded by the heater wire 2 is blank, and the trap is directly performed. -Because the filter 1 is heated, a local temperature difference occurs on the outer periphery of the filter 1 and fine cracks often occur.

Therefore, an object of the present invention is to provide a particulate trap which does not cause cracks on the outer periphery of the trap filter except for the above-mentioned drawbacks of the prior art.

[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 housed in a portion of the can between the inflow port and the outflow port and covers the outer periphery of the trap filter excluding the inflow surface and the outflow surface. ), And the gap between the heater wire and the portion of the outer periphery of the trap filter surrounded by the heater wire is electrically insulating material having good thermal conductivity. Filling made of glass layer.

[0016]

[Action]

 Since the trap filter is fixed inside the inner case (inner case), it is indirectly heated by the heater wire through the wall of the inner case. There are no small cracks due to the difference. In addition, since the gap between the heater wire and the portion around the heater wire surrounding the trap filter is filled with a layer made of an electrically insulating material having good thermal conductivity, the inner case is heated by heating. Even if it is distorted, it does not come into contact with the heater wire, and the heating effect is maintained at the same level as when it is not filled with the heat conductive electrically insulating material layer.

[0017]

【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 ceramic fiber, 4 is also a heat insulating material made of ceramic fiber, 5 is a heater terminal, and 6 is a temperature. A sensor 13 is a diffuser portion of the can body D.

As a new part, 7 is an inner case, 8 is a heater chamber, 9 is a wire mesh, 10 is a fixed flange, 11 is a detachable flange, 12 is an asbestos gasket, and 15 is alumina. It is paper. That is, in this embodiment, alumina paper is used as the "layer made of an electrically insulating material having good thermal conductivity".

As shown, the trap filter 1 is fixed inside the inner case 7, and the heater wire 2 is held inside 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 gap between the heater wire 2 and the portion of the outer circumference of the inner case 7 around which the heater wire 2 is provided is filled with the alumina paper 15, even if the inner case 7 is distorted due to heating, the heater wire 2 is distorted. It does not come into contact with the material 2, and the heating effect is maintained at the same level as when it is not filled with alumina paper 15.

The heater wire 2 is held and fixed in the heater chamber 8 in proximity to the inner case 7, and the heat generated in the heater wire 2 is prevented from reaching the can body D. Is filled with a heater holding heat insulating material 3. 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 exhaust gas inlet a side end and the exhaust gas outlet b side end of the inner case 1 and that of the can body D and the diffuser portion 13 of the can body D. Flange is also formed at the corresponding position. 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 a gasket, so that when the trap filter is difficult to regenerate, the bolts described above are used. The trap filter can be easily replaced in one place with the inner case by removing and tightening. Moreover, since bolting is performed through the gasket, the exhaust gas does not leak from the can body D after tightening.

[0023]

[Effect of device]

 As described above, according to the present invention, fine cracks do not occur in the outer periphery of the trap filter, and even if the inner case is distorted by heating, it does not come into contact with the heater wire. Since a bare wire can be applied to the heater wire, an economical particulate trap with a high heating effect can be realized.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view of a conventional particulate trap.

FIG. 3 is a 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 14 Bolt 15 Alumina Paper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Matsuda 1-chome, Ii-chome, Ageo City, Saitama Prefecture Nissan Diesel Industry Co., Ltd. (72) Tadashi Ishii 1-chome, Io-chome, Ageo City, Saitama Prefecture Nissan Diesel Industry Co., Ltd. (72) Inventor Kozo Ogasawara 4-14-1, Suehiro, Kumagaya-shi, Saitama Stock company Riken Kumagaya Works

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 housed in a portion of the can between the inflow port and the outflow port, and is fixed in an inner case that covers the outer periphery of the trap filter excluding the inflow surface and the outflow surface, The gap between the heater wire and the portion of the outer circumference of the inner case surrounded by the heater wire is filled with a layer made of an electrically insulating material having good thermal conductivity. Particulate trap to butterflies.