JPS6233941Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust purification device installed in an exhaust system of an internal combustion engine, and particularly to an exhaust purification device for a dual exhaust system using a monolith catalyst.

Conventionally, monolithic catalysts have the advantage of quick warm-up characteristics, and have therefore been used in internal combustion engines in such a way that they are installed immediately downstream of the exhaust manifold to take advantage of the above advantages as much as possible.
In this case, a monolithic catalyst is generally placed at a point where the exhaust pipes of each cylinder are collected into a single flow, and the exhaust gas is guided here, so interference between the exhaust gases of each cylinder is unavoidable. As a result, the output performance of the engine inevitably decreases. However, if the catalyst is installed far away from the exhaust manifold to avoid the effects of exhaust interference, it will not be possible to take advantage of the warm-up characteristics of the monolith catalyst. If you want to pass the exhaust gas from two cylinders together through a catalyst, you will need two catalysts in the case of a four-cylinder engine.

In view of the above problems, this invention satisfies the desire to install the monolith catalyst as close to the exhaust system as possible to reach the activation temperature quickly, to avoid exhaust interference between each cylinder, and to solve the problem with a single catalyst. The purpose of this system is to create a dual exhaust system that uses only one catalyst to take advantage of the warm-up characteristics of a monolithic catalyst and has good exhaust efficiency without exhaust interference between cylinders. The present invention provides an exhaust purification device for an internal combustion engine.

In order to achieve the above objectives, this invention
A monolithic catalyst is installed in a dual exhaust passage of an internal combustion engine, having a plurality of stacked, mutually independent exhaust passages, and each of the independent exhaust passages intersects with each other. be.

Embodiments of the present invention will be described below with reference to the drawings.

In Figure 1, 1 is a 4-cylinder engine, and its exhaust system consists of exhaust ports 2, 3, 4, and 5 for each cylinder.
Among them, the first exhaust port 2 has no exhaust interference with each other.
and the fourth exhaust port 5 are combined into one outlet 6.
Similarly, the second exhaust port 3 and the third exhaust port 4 are combined into one outlet 7 without exhaust interference.
It is a dual exhaust passage with several parallel outlets. A catalyst case 8 is connected directly below these two parallel outlets 6 and 7, and furthermore, this catalyst case 8
is connected to an exhaust pipe 9, where the exhaust gas is finally collected into one pipe. Reference numeral 10 denotes a monolithic catalyst such as monolithic ceramic, which is housed in a catalyst case 8 and purifies exhaust gas in a dual exhaust pipe (catalyst case 8) that continues to the parallel outlets 6 and 7.

As shown in FIG. 2, the structure of the monolithic catalyst 10 is a rectangular parallelepiped as a whole, and has a structure in which a large number of independent exhaust passages 11 to 18 are stacked, and the exhaust passages 11 to 18 are arranged alternately in the direction of the passage. They are arranged so that they are different and orthogonal. That is, every other exhaust passage 11, 13, 15, 17 is in the same direction, and every other exhaust passage 12, 14, 1
6 and 18 are configured to face in a direction perpendicular to this. As shown in FIG. 1, this monolithic catalyst 10 is disposed at a position where one of its diagonals coincides with the partition wall 19 at the center of the dual exhaust passage (catalyst case 8) in plan view.

By arranging the monolith catalyst 10 as described above, the exhaust from the outlet 6 where the first exhaust port 2 and the fourth exhaust port 5 are combined into one (this exhaust does not interfere with each other) is Monolith catalyst 10
Every other exhaust passage 12, 14, 1 of the laminated passage
6 and 18 in the direction of the arrow in FIG.
The exhaust gas enters an exhaust passage 20 on the opposite side to 9, during which time the exhaust gas is purified by the action of a catalyst 10. Similarly, the exhaust from the outlet 7 where the second exhaust port 3 and the third exhaust port 4 are combined into one (does not interfere with each other) is sent to the other exhaust passages 11 of the catalyst 10,
13, 15, and 17, the gas flows in a direction perpendicular to the flow from the outlet 6, and enters the exhaust passage 21 on the opposite side to the partition wall 19. In this way, the exhaust gases supplied from the outlets 6 and 7 do not mix in the catalyst 10, and interference between them can be avoided. Furthermore, even if the exhaust gas temperature on the outlet 7 side is low, if the exhaust gas temperature on the other outlet 6 side is high, the exhaust passages 11, 13 through which the low temperature exhaust passes,
Since the catalysts 15 and 17 are heated from above and below by the high-temperature exhaust gas from the outlet 6 side, the catalyst function is activated and the function of the catalyst 10 as a whole can be improved.

In the above embodiment, the monolithic catalyst 10 has a rectangular parallelepiped shape, that is, a quadrangular shape in a plan view, but it may also have a circular cylindrical shape in a plan view. When a catalyst with this shape is used, the exhaust passage is generally located at the center of the catalyst. Since the flow velocity is faster than that at the edges, the exhaust passage of this catalyst is long in the center and short at both ends, so the flow velocity of exhaust gas in the catalyst is uniform throughout each part. Therefore, the catalytic effect can be further improved.

The present invention is as described above, so that even if the catalyst is installed in the dual exhaust passage, the exhaust performance of the dual exhaust system is not impaired, and the advantages of the monolithic catalyst, which has quick warm-up characteristics, are fully utilized. Moreover, only one catalyst is required, and even when there is a difference in exhaust gas temperature, the catalyst can be efficiently heated and its functions can be improved.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of an embodiment of the present invention, and FIG. 2 is a schematic enlarged perspective view of a monolithic catalyst used in the embodiment. 1... Engine, 2, 3, 4, 5... Exhaust port, 6, 7... Exhaust outlet, 8... Catalyst case, 1
0...Monolith catalyst, 11-18...Exhaust passage.

Claims (1)

[Claims for Utility Model Registration] 1. A monolithic catalyst having a plurality of laminated mutually independent exhaust passages in a dual exhaust passage of an internal combustion engine and configured such that each of the independent exhaust passages intersects with each other. An exhaust purification device characterized by having been installed. 2. The exhaust gas purification device according to claim 1, wherein the monolithic catalyst has a rectangular shape in plan view, and is arranged such that one of its diagonals is located in the axial direction of the dual exhaust passage. 3. The exhaust purification device according to claim 1, wherein the monolithic catalyst has a circular shape in plan view.