JPS6035524B2 - Catalytic exhaust gas purification muffler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a catalytic purification muffler that is connected to an exhaust manifold outlet of an engine and purifies exhaust gas.

BACKGROUND ART Conventionally, catalytic mufflers for purifying engine exhaust gas have been used in construction machines operating in tunnels from the viewpoint of working environment hygiene.

As shown in FIG. 1, this muffler introduces exhaust gas from an exhaust manifold 2 of an engine 1 through an inlet portion 3, purifies it by contact with catalyst pellets filled in a muffler 4, and then directs the exhaust gas through an outlet portion. It is designed to be discharged from 5. However, in the above-mentioned conventional muffler, the exhaust gas flowing inside the muffler from the inlet section 3 toward the outlet section 5 tends to flow only along a specific route inside the muffler as shown by the arrow in the figure, and the catalyst inside the muffler There is a drawback that the purification efficiency is low because it is not possible to obtain uniform contact with the entire surface. For this reason, conventional mufflers require a large amount of catalyst pellets in order to obtain a predetermined purification efficiency, making the entire muffler large and heavy. Such a large and heavy muffler is not only inferior in economy and serviceability, but also cannot be installed inside the engine room 6, so it must be installed above the engine room 6 so as to obstruct the driver's view as shown in the figure. This results in a decrease in work efficiency. In addition, as a catalyst muffler for internal combustion engines, the catalyst chamber is formed by punching metal covered with two wire meshes facing each other in the center of the horizontally arranged cylindrical body, and the catalyst chamber is formed in the center of the end plates provided at both ends of the body. An intake pipe and an exhaust pipe are installed respectively, and a diffusion plate is provided inside the main body opposite to the intake pipe, and the exhaust gas introduced from the intake pipe is made to collide with the diffusion plate and dispersed, and then passes through the catalyst chamber. Things are also known (Jitko Sho 46-280
(see issue). This structure is superior to the structure shown in FIG. 1 in that the exhaust gas can be dispersed and efficiently brought into contact with the catalyst. However, the structure has two horizontally spaced
Because the catalyst chamber formed by two punched metal sheets is filled with catalyst pellets, the packing density of the catalyst becomes coarse in the upper part of the catalyst chamber and denser in the lower part due to vibrations, etc., resulting in a uniform flow between the exhaust gas and the catalyst. Contact cannot be obtained and an efficient purification effect cannot be obtained. Furthermore, if pellets are filled from time to time in order to compensate for the decrease in pellets in the upper part of the catalyst chamber, the packing density in the lower part of the catalyst chamber becomes excessive and the exhaust resistance increases significantly. Furthermore, since the entire structure of the muffler is cylindrical, if the catalyst chamber is enlarged to increase the purification capacity, the entire muffler becomes large and heavy, and the muffler as a whole becomes large and heavy.
Like the one in the figure, there are problems in terms of economy, serviceability, and workability. The present invention has been made to eliminate the above-mentioned conventional drawbacks, and therefore, the catalytic muffler according to the present invention is a catalytic exhaust gas purifying muffler connected to an exhaust manifold outlet of an engine. The muffler is arranged almost vertically in the engine room, and has a main body that houses a catalyst, one end connected to the exhaust manifold outlet and the other end on the main body inlet side, and an inlet pipe connected to the center. , an outlet pipe having one end connected to the center of the main body outlet side and the other end being exposed outside the engine room,
The end of the inlet pipe projects into the main body and is provided with a plurality of openings for dispersing exhaust gas, and the inlet and outlet sides of the main body are connected to the inlet pipe and the outlet pipe from side walls, respectively. The inlet pipe has a tapered wall that gradually protrudes outward toward the main body, and the other end of the inlet pipe that protrudes into the main body has a tip, and the plurality of entrances protrudes into the main body. The catalysts falling into the inlet pipe are formed at approximately equal intervals around the main body, and between the inlet side tapered wall of the main body and the outer periphery of the other end of the inlet pipe protruding into the main body. A pocket portion is formed to prevent entry of the catalyst, and the catalyst contained in the main body is formed into a horizontal catalyst layer by a plurality of compartments divided vertically within the main body. shall be.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 shows an installation example of the catalytic purification muffler according to the present invention, in which the muffler 4 is arranged in the engine room 6, unlike the conventional arrangement, and the exhaust is directly routed from the exhaust manifold 2 through the inlet pipe 7. After the gas is received and purified, it is discharged to the outside of the engine room 6 via an outlet pipe 8.

Therefore, the muffler according to the present invention is significantly smaller and lighter than conventional mufflers. Figures 3 to 5 are
This is an embodiment of the muffler of the present invention which is small and lightweight, and the muffler 4 according to the embodiment has an oval horizontal cross section and a polygonal vertical cross section as shown in the figure. It consists of a hollow main body part 9, an inlet pipe 7 and an outlet pipe 8 connected to the center of the main body part 9 at the inlet and outlet sides, respectively. The main body part 9 is
Side wall 11 forming a cylindrical body with a substantially oval horizontal cross section
and a bottom wall 12 connecting between the lower end green and the upper end green of the side wall 11 and the inlet pipe 7 and the outlet pipe 8, respectively.
and a top wall 13.・These bottom wall 12 and top wall 1
3, as shown in the figure, the pipes 7 and 8 are connected from the green end of the side wall 11.
It is tapered so as to gradually protrude outward toward the connecting part. By providing tapered walls on the inlet and outlet sides of the main body, the exhaust gas introduced into the main body can flow smoothly and evenly throughout the main body. In addition, the tapered walls on the inlet and outlet sides of the main body make the entire device smaller and lighter, making it easier to place it in the engine room, even though the cross-sectional area of the catalyst pellet storage compartment described later is large. make it easier. side wall 11
As shown in the figure, the inside of the cylindrical body formed by
(Three compartments in the figure) are divided into a plurality of compartments 15 (two compartments in the diagram) that overlap vertically, and each compartment 15 receives granular catalyst particles through a closure 16 provided in a part of the side wall 11. The let 17 can be filled. The gate 16 is closed by a cover plate 19 which is removable by means of bolts 18. Since the catalyst pellet 17 can be divided and stored in a plurality of compartments 15 in this manner, the amount of the catalyst pellet can be adjusted in accordance with the volume of exhaust gas to be purified. For this reason, it is desirable to change the volume of each compartment 15 as shown in the figure. Further, as described above, the catalyst pellet 17 can be arranged in a plurality of compartments 15.
By storing the catalyst pellet in separate parts, the load of the catalyst pellet can be distributed and supported. By dividing and storing the catalyst pellets in a plurality of horizontally arranged compartments, the pellet density can be kept constant across the cross section of the compartments regardless of vibrations, etc. Uniform contact between the lets can be obtained. The inlet pipe 7 is connected to a center opening 2 of the bottom wall 12 of the main body 9 as shown in the figure.
0, and its lower end 21 is provided with a vertical slit 22 so that its radius can be contracted by a tightening band or the like when connected to the outlet of the exhaust manifold 2, and protrudes into the main body 9. The top checkpoint of the upper end 23 is the Uma plate 24
A plurality of openings 25 for distributing exhaust gases are provided around the inlet pipe 7 which is closed at and projects into the main body at approximately equal intervals.

In this way, the gas outlet end of the inlet pipe 7 connected to the outlet of the exhaust manifold 2 projects into the main body 9, and its top end is closed at Miyasaka, and a plurality of entrances 25 for gas dispersion are provided around it. By this, exhaust manifold 2
As shown by the arrow in the figure, the exhaust gas from the
After colliding with the catalyst 17, it is dispersed in all directions from the surrounding gate 25 and spreads over the entire area of the catalyst 17. Therefore, the exhaust gas comes into contact with the entire catalyst 17 evenly, thereby increasing the purification efficiency. In particular, since the catalyst comes into contact with high-temperature exhaust gas immediately after being discharged from the exhaust manifold 2, this also improves the purification efficiency. According to the experimental results, the muffler according to the present invention has a reduction of approximately 1'2 compared to the conventional muffler.
It was found that the same purification ability can be obtained with a catalyst amount of . Furthermore, by blocking the top entrance of the inlet pipe 7 with the cover plate 24 as described above, it is possible to prevent the falling catalyst pellets from entering the entrance pipe 7 and to reduce the noise of the exhaust gas. Furthermore, the seven-part-shaped bottom wall 12 of the main body portion 9
A pocket portion 26 is formed between the bottom wall 12 and the outer periphery of the inlet pipe 7 provided through the bottom wall 12, thereby preventing falling pellets from entering the inlet pipe 7 through the closure 25. ing. Note that the inlet pipe 7 is connected to the main body part 9.
A support bracket 27 is attached between the upper end of the inlet pipe 7 and the upper surface of the bottom wall 12 to firmly support the inlet pipe 7. Further, a service opening 28 is provided in a part of the bottom wall 12 for the purpose of servicing, such as removing pellets accumulated in the pocket portion 26, and the service opening 28 is detachable with a bolt 29 as shown in FIG. cover plate 30
'It's more covered. One end of the outlet pipe 8 is connected to the central opening 31 of the upper wall 13 of the main body 9, and the end thereof is exposed outside the engine room 2 and connected to a suitable exhaust pipe 32 (see Fig. 2). ).

Compared to conventional mufflers, the muffler having the above structure improves the purification efficiency of the catalyst due to uniform contact between the exhaust gas and the catalyst pellets, thereby reducing the amount of catalyst required for a given exhaust gas purification.

In addition to the reduction in the amount of catalyst mentioned above, the inlet and outlet sides of the muffler body are tapered, making the muffler overall smaller despite the large cross section of the pellet storage compartment.
It can be made lighter. A small, lightweight muffler like the one not only has excellent serviceability and economy, but as mentioned above, it can be installed inside the engine compartment, improving work efficiency without obstructing the driver's view. can be achieved. As described above, according to the present invention, it is possible to obtain a catalyst muffler that has good purification efficiency, is small in size and lightweight, and can be adhered to the inside of the engine room, and has excellent serviceability, economy, and workability.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of mounting a conventional muffler, FIG. 2 is a schematic diagram showing an example of mounting a muffler according to the present invention, FIG. 3 is a partially cutaway plan view of the muffler of the present invention, and FIG. The figure is a vertical sectional view of the same, and FIG. 5 is a view taken along the line V-V in FIG. 4. 1...Engine, 2...Exhaust manifold, 4...
Muffler, 6...Engine room, 7...Inlet pipe,
8...Exit pipe, 9...Main body, 12
...Bottom wall, 13...Next wall, 15...
... Ward compartment, 17... Catalyst, 21...
... lower end, 23 ... upper end, 24 ... name plate,
25...Closed mouth, 26...Pocket. Figure 2 of the map, Figure 4, Figure 5

Claims (1)

[Claims] 1 A catalytic exhaust gas purification muffler connected to the exhaust manifold outlet of the engine, which muffler is arranged almost vertically in the engine room, and has a main body in which a catalyst is housed, and one end connected to the exhaust manifold outlet. An inlet pipe that is connected and has the other end connected to approximately the center of the main body inlet side, and an outlet pipe that has one end connected approximately to the center of the main body outlet side and the other end exposed outside the engine room. The other end of the inlet pipe projects into the main body and is provided with a plurality of openings for dispersing exhaust gas, and the inlet and outlet sides of the main body are connected to the inlet pipe and the outlet pipe from side walls, respectively. The inlet pipe has a tapered wall that gradually protrudes outward toward the connecting portion, the other end of the inlet pipe that protrudes into the main body is blind, and the plurality of openings protrude into the main body. The inlet pipe is formed at approximately equal intervals around the inlet pipe, and the inlet pipe is formed between the inlet-side tapered wall of the main body and the outer periphery of the other end of the inlet pipe protruding into the main body. A pocket portion is formed to prevent the falling catalyst from entering, and the catalyst contained in the main body is formed into a substantially horizontal catalyst layer by a plurality of compartments divided into upper and lower sections within the main body. A catalytic exhaust gas purification muffler characterized by: