JPS5929721A - Catalytic conversion muffler for engine - Google Patents

Abstract

PURPOSE:To greatly lengthen the life of a catalyst, by providing a smoke removing filter layer upstream to a catalyst layer in the body of a case to extremely reduce the clinging of soot or smoke to the surface of the catalyst. CONSTITUTION:The lower end of a punched cylinder 4 serves as the inlet part a muffler and is connected to the outlet port 14 of an engine exhaust manifold. A catalyst holder 8 comprises an inner cylinder 16 fitted with the punched cylinder 4, an intermediate cylinder 20 holding a smoke or soot removing filter 18 such as glass wool together with the inner cylinder, an outer cylinder 24 holding a catalyst 22 for decreasing carbon monoxide, hydrocarbon, etc., together with the intermediate cylinder, and an upper and a lower unpunched plates 26, 28 covering the upper and lower ends of the inner, intermediate and outer cylinders. Exhaust gas flows radially outwards from the punched cyliner 4 through the layers of the filter 18 and the catalyst 22 and then flows radially inwards from the peripheral part of a case body 2.

Description

[Detailed description of the invention] The present invention relates to a catalytic purification muffler for engines.

Conventionally, when operating construction machinery in a closed space such as in construction work or subway construction, engine exhaust gas purification means have been used from the viewpoint of working environment hygiene. Catalytic mufflers are used to reduce carbon monoxide, hydrocarbons, etc. However, because the conventional fused W type 77 roller has a structure in which the exhaust gas from the engine exhaust manifold is introduced directly into the catalyst layer, smoke components or soot tend to adhere to the surface of the pellet-shaped or honeycomb-shaped catalyst. The disadvantage is that the catalytic function deteriorates very quickly. Since metal catalysts are not only expensive but also involve secondary industry pollution, it is becoming increasingly difficult to manufacture them, and from this point of view as well, it has been desired to extend the life of the catalyst.

The present invention has been made in order to eliminate such conventional drawbacks and meet the demand. To this end, the present invention includes a case body having an inlet portion and an outlet portion, the inlet portion being connected to the engine exhaust manifold outlet. In a catalytic purification muffler for an engine that is connected and includes a catalyst layer inside, a smoke removal filter is provided on the upstream side of the catalyst layer in the case body, so that soot components are removed from the exhaust gas and then passed through the catalyst layer. It is characterized by being made to do.

Hereinafter, preferred embodiments of the present invention shown in the accompanying drawings will be described.

FIG. 1 shows an embodiment of the present invention.
4 is the case body of the muffler, 4 is a perforated tube extending into the case body integrally formed in the center of the bottom wall 6 of the case body, 8
10 is a catalyst holder fitted around the perforated tube (4) in the case body 2; 10 is a lid body that closes the upper part of the case body 2;
Reference numeral 12 indicates an exhaust pipe integrated with the lid body 10, which forms the outlet portion of the muffler.

The lower end of the perforated tube 4 forms the inlet of the muffler and is connected to the outlet 14 of the engine exhaust manifold.

The catalyst holder 8 includes an inner cylinder 16 that fits into the perforated cylinder 4, and a middle cylinder 20 that holds a filter for removing smoke components or soot, such as glass wool, 18 between the inner cylinder 16.
An outer cylinder 2 holding a catalyst, for example, a platinum catalyst, 22 for reducing carbon monoxide, hydrocarbons, etc. between the inner cylinder 20
4, and a blind upper plate 26 and lower plate 2B that cover the upper and lower ends of the inner, middle, and outer cylinders 16, 20, and 24.

The inner cylinder 16, the middle cylinder 20, and the outer cylinder 24 are formed from a mesh plate or a punch plate.
20.24 is removably assembled together with upper and lower plates 26.28. The filter 18 layer and the catalyst 220 layer have a concentric double cylindrical structure centered around the perforated cylinder 4 and the inner cylinder 16 into which exhaust gas is introduced.

The upper lid 10 is removably fixed to the case body by bolts 34 securing the outer peripheral portion to a collar 32 attached to the inner surface of the cylindrical side wall 30 of the case body 20 via a gasket (not shown).

In the muffler having such a structure, the exhaust from the engine exhaust manifold flows radially outward from the perforated tube 4 through each layer of the filter 18 and the catalyst 22, as shown by the arrow in the figure, and further from the outer periphery of the case body 2. It flows radially inward and is discharged into the atmosphere from the exhaust pipe 12. Therefore, the exhaust from the engine exhaust manifold does not come into direct contact with the catalyst 22, but comes into contact with the catalyst 22 after most of the smoke components or soot is removed by the filter 18, so that the soot or smoke does not reach the catalyst surface. The sticking of components can be significantly reduced, thereby greatly extending the catalyst life.

FIG. 2 shows a modification of the present invention, which includes a case body 2' that can be opened and closed vertically, and a case body 2' that can be opened and closed vertically.
A cylindrical body 4', which serves as the inlet of the muffler, is provided at the center of the bottom wall 6' of the case body 2', and an exhaust pipe 12', which serves as the outlet of the muffler, is provided at the center of the earthen wall 10' of the case body 2'.
and a catalyst holder 8' supported within the case body 2'.

The lower end of the cylinder 4' is the outlet 14' of the engine exhaust manifold.
The upper end 4a' is a blind plate, and the side wall includes a plurality of holes 4b' for dispersing exhaust gas. Further, the catalyst holder 8' is removably formed from a mesh plate or punched metal, and can be removably attached to the case body 2'. The catalyst holder 8' has layers of a filter 18' and a catalyst 22' stacked vertically and arranged horizontally. Although the exhaust gas flows from the bottom to the top as indicated by the arrows in the figure, this modified example provides substantially the same effects as those of the previous embodiment.

Note that the holder 8' can be formed separately for the catalyst and the filter.

As described above, according to the present invention, it is possible to obtain a muffler that can extend the life of the catalyst to an extent [1].

[Brief explanation of the drawing]

FIG. 1 is a central sectional view showing an embodiment of the present invention, and FIG. 2 is a view similar to FIG. 1, showing a modification of the invention. 2.2'... Case body, 14.14' ・Exhaust manifold outlet, 18.18
′ Phil! -1 22,22' catalyst. Patent Applicant Caterpillar Mitsubishi Corporation (2 others) Mill Figure Qin 2 Figure 11

Claims (4)

[Claims] (1) A catalytic purification muffler for an engine including a case body having an inlet part and an outlet part, the inlet part being connected to the exhaust manifold outlet of the engine, and including a catalyst layer inside, wherein the catalyst layer is inside the case body. A catalytic purification muffler for an engine, characterized in that a single layer of smoke removal filter is provided on the upstream side of the muffler. (2) The muffler according to item 1, wherein the inlet section is arranged at the center of the case body, and the smoke removal filter layer and the catalyst layer are arranged to form a concentric double cylindrical structure around the inlet section. (3) The muffler according to item 1, wherein the inlet section and the outlet section are provided at the bottom and top of the case body, respectively, and the smoke removal filter layer and the catalyst layer are vertically arranged in layers and arranged horizontally. (4) The muffler according to any one of items 1 to 3, wherein one layer of the smoke removal filter is made of glass wool and the catalyst layer is made of a platinum catalyst.