JPS61135921A - Exhaust manihold reactor - Google Patents

Abstract

PURPOSE:To improve an efficiency of purification of exhaust gas by a method wherein several layers at an outer circumferential side are made as thermal insulation layer and inner several layers are made as a catalyst carrying layer in a system in which a thermal insulation heat keeping body having a plurality of wound metallic plates in a proper thermal insulation space is arranged at an inner surface of the reactor. CONSTITUTION:An exhaust gas manihold reactor 2 discharges the gas from an exhaust gas pipe 4 after hazardous constituent in the exhaust gas introduced through a feeding pipe 3 is removed under a combustion reaction, and a thermal insulation heat keeping body 11 of hollow cylindrical member in which several layers with corrugated plates 9 and the planer plates 10 are combined and wound around an outer circumference of the thin-walled inner cylinder 8 is installed in the casings 2' and 2'' of two-divided structure. In this case, metallic powders showing catalyst action are spray coated on at least one of the corrugated plates 9 and the planer plates 10 of several layers 18 so as to form a permeable catalyst carrying layer. The remaining layers 19 are not processed with the treatment and then the non-permeable thermal insulation layer having a longer length than that of the layer 18 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in an exhaust manifold reactor suitable as an exhaust gas purification device for engines, particularly automobile engines.

[Problems with conventional technology]

In recent years, HC, a harmful component in exhaust gas from automobile engines,
In order to convert , Co, NOx, etc. into harmless components and discharge them into the atmosphere, a catalytic converter is installed in the middle of the exhaust system, or instead of the conventional exhaust manifold 1, harmful components in the exhaust gas are removed by thermal reaction. A manifold reactor, commonly called a thermal reactor, has been put into practical use.

As is well known, in the above manifold reactor,
In order to actively re-burn the harmful unburned components in the exhaust gas and improve the purification efficiency, it is necessary to provide sufficient heat insulation, so conventionally non-metallic heat insulation materials such as ceramic foam were used. was.

However, this type of non-metallic insulation is generally mechanically
1. Heat insulating material is housed in a double shell structure consisting of a cored actor casing that limits the re-combustion chamber of exhaust gas because it has poor strength and is easily corroded by contact with exhaust gas, and heat insulating material is housed in a double shell structure consisting of a cored actor casing that limits the re-combustion chamber of exhaust gas. The exhaust gas that has been reburned in the exhaust gas inlet pipe and the above-mentioned core is guided to the exhaust pipe. In order to prevent this, a seal ring is provided.However, the seal ring must exhibit sufficient sealing performance while allowing free thermal expansion and contraction of the casing and core, as well as the exhaust gas inlet pipe and the exhaust pipe. At the same time, sufficient consideration must be taken to prevent engine vibrations from colliding with surrounding parts such as the core, inlet pipe, and exhaust pipe, causing noise. As a result, the structure becomes extremely complex and expensive. Not only become.

There is a problem with the thermal fatigue resistance of the above-mentioned inorganic heat insulating material, and there is concern about its service life.

Furthermore, in Japanese Patent Application Laid-Open No. 49-20516, an inner cylinder main body formed in a spiral shape is disposed inside a closed cylindrical outer cylinder, and an inlet for exhaust gas is communicated with the inside of the inner cylinder. A manifold reactor is described in which an outer open end formed between a main body and an outer cylinder is communicated with an outlet, but this manifold reactor cannot obtain a heat insulation effect due to the inner cylinder main body. Moreover, there was a problem that the exhaust gas purification efficiency was inferior because the catalyst did not have a purifying effect.

[Means for solving problems]

The present invention was devised to eliminate the above-mentioned drawbacks of the conventional manifold reactor, and is made by winding multiple layers of metal plates on the inner surface of a casing that receives engine exhaust gas and recombusts it, with an appropriate heat insulating space. in which a part of the layer of the heat insulating body close to the inner surface of the casing is a non-breathable layer formed so that exhaust gas does not flow through the heat insulating space. The gist of the exhaust manifold reactor is that the exhaust manifold reactor is formed as a heat insulating layer, and the remaining layer is formed as an air-permeable catalyst carrier formed so that exhaust gas flows within the heat insulating space. .

〔Effect of the invention〕

According to the present invention, a heat insulating body formed by winding a plurality of layers of metal plates with an appropriate heat insulating space is interposed on the inner surface of the exhaust manifold reactor, so that it has excellent vibration resistance and thermal fatigue resistance, and Since there is no noise, there is no need to get used to generating noise, and the structure is extremely simple, which has the effect of reducing manufacturing costs.

Further, a part of the layer close to the inner surface of the casing has a practically sufficient heat-insulating effect, and the exhaust gas is effectively re-combusted by the catalyst supported on the remaining layers.

〔Example〕

The present invention will be described below as a manifold reactor for a four-cylinder engine (
An embodiment applied to a reactor (hereinafter simply referred to as a reactor) will be specifically described with reference to the drawings.

First, FIGS. 1 to 6 show a first embodiment of the present invention, in which a reactor, generally designated by the reference numeral 2, is attached to the side of a cylinder head 1. In FIG.

T・Exhaust gas from the engine is cylinder head 1 (not shown)
The gas is introduced into the reactor through the inlet pipe 3 from the exhaust port of the reactor, undergoes a combustion reaction in the reactor, flows to the exhaust pipe 4, and is discharged to an exhaust pipe (not shown).

The reactor 2 has an overall cylindrical shape and includes an upper and lower casing 2' divided into two parts along a plane including the longitudinal centerline 0-0, and the lower casing 7 has bolts attached to the cylinder head 1. It is provided with a 7 flange 5 which is fixed by suitable fastening means, a tubular part 6 into which the introduction pipe 6 is inserted, and a tubular part 7 into which the discharge pipe 4 is inserted. The inlet pipe 3 and the discharge pipe 4 are preferably made of heat-resistant and corrosion-resistant stainless steel material, and the casings 2', 7
It may be made of inexpensive cast iron, or it may be assembled by welding plate materials as sheet metal processing.

Inside the casing 2-2#, as shown in FIG. 3, there is a hollow cylindrical heat-insulating heat insulating material formed by winding a full gate plate 9 and a flat plate 10 wound together in multiple layers around the outer periphery of a thin inner cylinder 8. The body 11 is installed inside. The above corrugated plate 9 and flat plate 1o
The winding start end is welded onto the thin-walled inner cylinder 8 or the filter part 1
Fixed by 2.

After a predetermined number of layers and volume number, a thin-walled outer cylinder 1 is fitted onto the outside to produce a heat insulating body 11. A stud bolt 14 is welded and fixed onto the tube 16, and the bolt 14 is inserted into a corresponding bolt hole provided on the wall surface of the upper casing 2', and the nut 15 is tightened to firmly secure the heat insulating body 11 within the casing. can be supported. Note that instead of the thin outer cylinder 13, only the flat plate 10 may be wound in any number of layers after a predetermined number of layers have been combined, and the terminal edge thereof may be fixed by welding or the like.

Both end openings of the heat insulating body 11 are closed by shielding plates 16, and a disc-shaped heat insulating material 17 made of ceramic fiber or the like is interposed between the shielding plates 16 and the casing 212''.

Then, at least one of several layers 18 of corrugated plates 9 and flat plates 10 from the center is spray-coated, vapor-deposited or plated with metal powder having a catalytic action, and
The corrugated plate and flat plate of the outer layer 19 do not have a catalyst and have a longer longitudinal dimension than the catalyst supporting layer 18, so that when the heat insulating body 11 is installed inside the casing, the shielding plate 17 and the catalyst A gas folding chamber 20 is provided between the support layer 18 and the support layer 18 .
is starting to form. Further, although the hole on the heat insulating body 11 that accommodates the discharge pipe 4 does not penetrate through the thin inner cylinder 8 and reaches the corrugated plate 9 of the first layer, the inner end of the discharge pipe 4 is connected to the catalyst support layer. 1B and the outer layer 19, it enters the folding chamber 20 while being reburned in the hole, and is rendered harmless by the action of the catalyst while flowing between the catalyst support layer 18 and the discharge pipe. flows from ~ into the exhaust pipe.

In the reactor 2 configured as described above, the heat insulating body 1
1 is made by winding multiple layers of thin metal full gate plate 9 and flat plate 10, it has excellent vibration resistance and thermal fatigue resistance compared to conventional ceramic or glass fiber heat insulators, and is movable. Since there are no parts, it is easy to get used to the noise generation, and the structure is extremely simple, which has the advantage of reducing manufacturing costs.

Furthermore, the gas temperature inside reactor 2 is usually 3D O6C
~1ooo'c, but since most of the heat transfer in this case is radiation heat transfer, the heat insulating property of the heat insulating body 11 having several layers of heat insulating spaces as described above is usually 2. It is practically sufficient to have 5 to 8 layers.

In addition, FIG. 4 shows a second embodiment of the present invention, and FIG. 5 shows a sixth embodiment of the present invention. A catalyst supporting layer 1B is provided at the center of the 1% center area, and an outer heat insulating layer 19 having only a heat insulating effect and having no catalyst is provided on the outside thereof. In the embodiment shown in FIG. 4, the folding chambers 2 at both ends of the catalyst support layer 18 are
o is formed in the shape of a truncated cone.

Furthermore, the hole into which the introduction tube 6a is to be fitted does not penetrate through the inner cylinder 8a, but reaches as far as the first layer corkate plate on its outer periphery, and the inner end of the introduction tube 3a is located at the boundary between the catalyst support layer 1B and the outer layer 19. The inner end of the discharge pipe 4a passes through the inner cylinder 8a. Therefore, the exhaust gas from the engine flows from the inlet pipe 3 through the catalyst support layer 18, and during this period, when the harmful components in the gas are re-burned, they are at least partially converted into harmless substances by the action of the catalyst, and then the It is re-combusted in the cylinder 8a and is discharged to the exhaust pipe 4a.

Furthermore, in the embodiment shown in FIG. 5, the inner cylinder 8a in the second embodiment is abolished and a central shaft 21 is provided instead.

Both ends of the concentric shaft 21 are supported on the casings 2', 2', and the inner end of the discharge pipe 4b is placed at the boundary between the outer heat insulating layer 19 and the catalyst support layer 18', just as in the first embodiment. It is located. In this device.

While the exhaust gas introduced from the inlet pipe 6b flows through the catalyst supporting layer 18, its harmful components are re-burned and at the same time the conversion action by the catalyst is removed, and most of them become harmless substances and are discharged from the exhaust pipe 4b. Ru.

FIG. 6 shows a fourth embodiment of the present invention, which purifies harmful components in the engine exhaust gas by re-combustion and/or catalytic action while flowing vertically downward. This is often referred to as a "funbuster". However, in a broad sense, it is included in manifold reactors. In the figure, 22 indicates cylinder head 1, and an exhaust gas collecting cover that communicates with the exhaust port of cylinder head 1;
24 is a body portion, and 24 is a lower lid connected to an exhaust pipe. Torso 2
A heat insulating body 11C similar to those in the third to fifth embodiments is housed in the interior of the third to fifth embodiments.
It comprises a medium carrying layer 18 and an outer heat insulating layer 19 on its outer part. Further, a partition plate 2526 is interposed at the joint between the lower lid 24 of the collecting lid 22 and the body 23 in order to prevent exhaust gas from flowing into the outer heat insulating layer 19. Therefore, the engine exhaust gas first enters the collecting lid 22,
While being guided by the partition plate 25 and flowing down the catalyst support layer 18, it is re-burned, purified by the action of the catalyst, and discharged into the exhaust pipe. The first to fourth heat insulating bodies 11.11a to 11C each have a catalyst layer 18 and an outer heat insulating layer 19.
In the embodiment, the outer heat insulating layer 19 has a practically sufficient heat insulating and heat retaining effect, and also exhibits the aforementioned various effects superior to conventional inorganic heat insulating materials.

Furthermore, FIG. 7 shows an embodiment in which a metal lath plate with a full gate is used as a modification of the corrugated plate 9, and this and a flat plate are wound together to produce a heat insulating body. In this modification, the contact heat transfer area is naturally reduced compared to the case where the flat plate is corrugated, so the heat insulation properties are even better, and when the catalyst support layer 18 is provided, the contact area between the exhaust gas and the catalyst is reduced. There are advantages such as an increase in the size and a reduction in weight.

Next, FIG. 8 shows an example of a structure for attaching the inlet pipes 3, 3a, 3b and the discharge pipes 4.degree. 4a, 4b to the heat insulating body constructed as described above. That is, holes for the inlet pipe and discharge pipe are drilled in the heat insulating body formed as described above. In this case, deformation during processing can be avoided by filling the space with water and freezing it.) It is preferable that a cylindrical spacer 60 having a flange 29 prepared in advance is fitted therein and fixed to the heat insulating body by welding 31, and the above-mentioned inlet pipe and discharge pipe are installed inside the spacer 0. In addition, as shown in FIGS. 9A and 9B, holes with a diameter d smaller than the outside diameter of the inlet pipe and the outlet pipe are punched in advance at predetermined positions on each plate constituting the heat insulating body by press working. After winding each plate, the edge of the hole having the diameter d may be bent to obtain a desired diameter.

Finally, what is the material of each plate that makes up the above-mentioned heat insulating body?

Stainless steel or nickel alloys are suitable, and the thickness of each plate is approximately 0.05 to 0.3 mm, but various design factors such as heat retention, catalytic effect, rigidity, and durability of the tube may be considered. Metal materials, thickness, shape, etc. other than those mentioned above may be appropriately selected depending on the requirements. Further, the catalyst supporting layer 1
The composition of the catalytic metal or alloy coated on the plate material in step 8 includes common elements such as Ni, Cr, Co, Cu, and Mn, as well as Pt, which acts effectively in exhaust gas purification as each metal oxide when the temperature rises. , Ru, Rh and other metal-free rare elements can also be widely used.

2. In the reactor of the present invention, it is preferable that the constituent plates in the heat insulating layer and the catalyst layer not be fixed together in order to maximize the flexibility of thermal deformation, but if necessary, for example, N1-CrB The fixation may be achieved by high temperature brazing using a brazing agent such as -8t alloy.

Additionally, a non-metal such as a thin layer of ceramic fiber can be interposed between the outer periphery of the heat insulating layer and the outer shell of the lid 7 to assist in heat insulation and noise prevention.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing a first embodiment of the manifold reactor of the present invention, FIG. 2 is a cross-sectional view cut along the line ■-■ in FIG. 1, and FIG. FIG. 4 is a cross-sectional view similar to FIG. 2 showing a second embodiment of the present invention, and FIG. 5 is a sixth embodiment of the present invention. FIG. 6 is a longitudinal sectional view showing a fourth embodiment of the present invention; FIG. 7 is a perspective view showing still another modification of the heat insulating body; FIG. The figure is a perspective view illustrating the procedure for machining the tube hole of the heat insulating body. FIGS. 9A and 9B are a plan view and a sectional view illustrating the procedure for forming a tube hole on the heat insulating body. 2. Manifold reactor. 2'2"...Gauge nog. 11 11a 11b 11c ##, -insulation heat insulator.

Claims (1)

[Claims] A heat insulating body formed by winding multiple layers of metal plates and having an appropriate heat insulating space is interposed on the inner surface of a casing that receives engine exhaust gas and recombusts it, wherein the heat insulating body is A part of the layer close to the inner surface of the casing is formed as a non-breathable heat insulating layer to prevent exhaust gas from circulating within the heat insulating space, and the remaining layer is formed to allow exhaust gas to flow within the heat insulating space. Exhaust manifold reactor, characterized in that it is formed as a formed breathable catalyst support