JPH03202606A - Exhaust gas cleaning device for engine - Google Patents

Abstract

PURPOSE:To eliminate soot efficiently by adopting such a means that exhaust led-in from an exhaust leading-in passage is turned in a branch chamber, and soot in exhaust gas is collected along the circumference of the branch chamber so as to let it flow into an exhaust flow-in passage without being discharged from a both-ends opening passage, and the like. CONSTITUTION:In a ceramic filter 4 stored inside an exhaust gas cleaning chamber 2, a plurality of exhaust communicating passages 5 are formed while its exhaust gas inlet 6 is opened to an inlet side branch chamber 7, and also its exhaust outlet 8 is opened to an outlet side confluence chamber 9 respectively. In such a device, the exhaust gas communicating passage 5 is formed with an one-end closed passage 10 and a both-ends opened passage 11. For example, in the one end closed passage 10, an exhaust flow-in passage 12 forming the exhaust inlet 6 on a starting end part is communicated to an exhaust flow-out passage 14 forming the exhaust outlet 8 on a terminating end part through a filter wall 13. Also, the exhaust gas inlet 6 of the both-ends opened passage 11 is opened to the center part of a filter starting end surface 29. Moreover, an exhaust gas leading-in passage 30 is communicated to the branch chamber 7 tangentially.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an engine exhaust purification device.

[Basic Structure] The basic structure of the exhaust purification device, which is the premise of the present invention, is as follows.

For example, as shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, or FIG. The ceramic filter 4 has a honeycomb shape with a plurality of exhaust flow passages 5 formed therein, and the exhaust inlet 6 of each exhaust flow passage 5 faces the branch chamber 7 on the inlet side of the exhaust purification chamber 2. In addition, the exhaust outlet 8 is opened to face the merging chamber 9 on the outlet side.

[Prior Art] As a specific structure of a ceramic filter having the above-mentioned basic structure, there is conventionally one shown in FIG. 4 (hereinafter referred to as "Prior Art 1").

This is a ceramic filter 4 in which a catalytic function for exhaust purification is imparted to the ceramic filter 4 itself using platinum or the like, and the exhaust flow path 5 consists of open passages 11 at both ends, each of which forms an exhaust inlet 6 at its starting end. An exhaust outlet 8 is formed at its terminal end.

Therefore, although carbon monoxide and hydrocarbons in the exhaust gas 15 are purified during the process of passing through the both-end open passage 11, there is no room for the soot in the exhaust gas 15 to be captured as it is, so the soot cannot be removed. .

As a solution to the problem of the prior art I, there is a conventional technology shown in FIG. 5 (hereinafter referred to as "prior art 2").

In this case, the exhaust flow passage 5 is composed of a closed passage 10 at one end,
This one-end sealed passage 10 is constructed by communicating an exhaust inflow passage 12 with an exhaust outflow passage 14 via an open cell passage in the filter wall 13, and the exhaust inflow passage 12 has an exhaust inlet 6 at its starting end.
and close the terminal end of the exhaust flow path 1.
4 has its starting end closed and an exhaust outlet 8 formed at its terminal end.

[Problem to be Solved by the Invention] Therefore, in the above-mentioned prior art 2, in the process of the exhaust gas 15 passing from the exhaust gas inflow path 12 through the open cell passage in the filter wall 13 and flowing into the exhaust gas outflow path 14, the exhaust gas 15 can be captured on the inner circumferential surface 16 of the exhaust inflow path 12, but the following new problem arises.

Since the flow of the exhaust gas 15 encounters a large resistance while passing through the open cell passage in the filter wall (3), the back pressure of the exhaust gas 15 increases, preventing scavenging of the cylinder chamber, and the output performance of the engine is low.

An object of the present invention is to make it possible to remove soot from exhaust gas while maintaining a low exhaust back pressure.

[Means for Solving the Problems] (First Invention) The first invention is characterized in that, in the basic structure described above, the specific structure of the ceramic filter is as follows.

For example, as shown in FIG. 1 or 3, the exhaust flow passage 5 has a closed passage 10 at one end and an open passage 11 at both ends.
The exhaust inflow path 12 has an exhaust inlet 6 at its starting end and is closed at its terminal end.
closes its starting end and forms an exhaust outlet 8 at its terminal end, and the both-end open passage 11 has an exhaust inlet 6 at its starting end.
The exhaust inlets 6 of the plurality of both-end release passages 11 are opened near the center of the starting end surface 29 of the ceramic filter 4, and the exhaust inlets 6 of the plurality of both-end release passages 11 are opened at the central part of the starting end surface 29 of the ceramic filter 4, and a plurality of exhaust inlets 8 are formed in the peripheral part thereof. The exhaust inlet 6 of the closed passage 10 is opened at one end, and the exhaust introduction passage 30 is tangentially communicated with the branch chamber 7.

[effect] The present invention provides the following effects (1) and (2).

■In the process of exhaust gas flowing from the exhaust inflow path through the open cell passage in the filter wall and into the exhaust outflow path, soot in the exhaust is captured on the inner circumferential surface of the exhaust inflow path, and some of the exhaust gas is released from the diverting chamber to the merging chamber via the open passages at both ends, suppressing the increase in exhaust back pressure in the diverting chamber, and improving the scavenging of the cylinder chamber. Can remove soot.

■The exhaust gas introduced from the exhaust inlet is swirled in the diversion chamber, and the soot with a large mass is collected around the diversion chamber, and the soot is allowed to flow into the exhaust inlet passage without escaping from the open passages at both ends.
High soot removal performance.

[Example code] Embodiments of the present invention will be described based on the drawings.

1 and 2 are diagrams for explaining an engine exhaust purification device according to a first embodiment of the present invention, FIG. 1(A) is a longitudinal sectional view of the exhaust gas purification device, and FIG. 1(B) is a B- in Figure 1 (A)
A cross-sectional view taken along line B, FIG. 2 is a vertical cross-sectional front view of the upper part of the engine, and FIG. 3 is a bottom view of the ceramic filter of the second embodiment.

First, a first example will be described.

In FIG. 1, the symbol l indicates an engine.

This engine is a sub-combustion chamber type diesel engine,
Air is supplied from an air cleaner (not shown) through the intake passage 17 to the cylinder chamber 18, and is then supplied to the cylinder chamber 18 from the fuel injection pump (not shown).
Fuel is pumped from the fuel injection nozzle 20 to the auxiliary combustion chamber 21 with a pressure of
The exhaust gas 15 is injected into the cylinder chamber 18, mixed with the air in the cylinder chamber 18, and combusted, and the exhaust gas 15 is released into the atmosphere from the cylinder chamber 18 through the exhaust port 26, the exhaust passage 3, and the muffler 22 in this order.

The engine 1 includes a cylinder head 24 mounted on the upper part of a cylinder block 23, a cylinder 25 formed inside the cylinder block 23, and an auxiliary combustion chamber 21 inside the cylinder head 24.
, an exhaust port 26, etc. are formed, and an exhaust manifold 27, an exhaust purification device 28, and a muffler 22 are arranged on the side of the cylinder head 24.

The exhaust purification device 22 includes an exhaust manifold 27 and a muffler 2.
2, the exhaust purification chamber 2 is interposed in the exhaust passage 3.

The exhaust purification chamber 2 houses a ceramic filter 4.

The ceramic filter 4 is provided with a catalytic function for purifying exhaust gas using platinum or the like, so that it can purify carbon monoxide and hydrocarbons in the exhaust gas 15 that passes through it.

As shown in FIG. 1, the ceramic filter 4 has a honeycomb shape with a plurality of exhaust flow passages 5 formed therein, and the exhaust inlet 6 of each exhaust flow passage 5 is connected to a branch chamber 7 on the inlet side of the exhaust purification chamber 20. The exhaust outlet 8 is opened facing the merging chamber 9 on the exit side.

The ceramic filter 4 is integrally formed.

The exhaust flow passage 3 has a closed passage 10 at one end and an open passage 11 at both ends.
It is configured so that it communicates with 4.

Further, the exhaust inflow path 12 has an exhaust inlet 6 at its starting end and is closed at its terminal end, and the exhaust outflow path 14 has its starting end closed and an exhaust outlet 8 at its terminal end, and both ends are open. The passage 11 has an exhaust inlet 6 at its starting end and an exhaust outlet 8 at its terminal end, so that the exhaust 15 passes from the exhaust inlet passage 12 through the open cell passage in the filter wall 13. Exhaust outlet passage 14
In the process of flowing into the exhaust gas 15, the soot in the exhaust gas 15 is transferred to the exhaust gas inflow path 12.
In addition to capturing the exhaust air 15 on the inner circumferential surface 16 of the passage, a part of the exhaust gas 15 is released from the branching chamber 7 to the merging chamber 9 via the both-end open passages 11,
It suppresses the increase in back pressure of exhaust gas in the diverter chamber 7, and
This makes it possible to improve the scavenging air of the engine 8 and remove soot from the exhaust gas 15 while improving the output performance of the engine 1.

Further, the exhaust inlets 6 of the plurality of both-end open passages 11 are opened in a central part of the starting end surface 29 of the ceramic filter 4, and the exhaust inlets 6 of the plurality of one-end closed passages 10 are opened in the surrounding area.
By opening the exhaust gas introduction path 30 and connecting the exhaust gas introduction path 30 to the separation chamber 7 in a tangential manner, the exhaust gas 15 introduced from the exhaust gas introduction path 30 is swirled in the separation chamber 7, and the soot with a large mass is transferred to the separation chamber 7. The soot is collected in the surrounding area, and is allowed to flow into the exhaust gas inlet passage 12 without escaping from the both-end open passages 11, thereby improving the soot removal performance.

As shown in FIG. 3, in the second embodiment, instead of forming the ceramic filter 4 integrally in the first embodiment, it has a cylindrical center portion 31 and a cylindrical peripheral portion 32. The both-end open passages 11 are formed inside the central part 31, the negative-end closed passages 10 are formed inside the peripheral part 32, and the peripheral part 32
The center portion 31 is fitted inside.

[Brief explanation of drawings]

1 and 2 are diagrams for explaining an engine exhaust purification device according to a first embodiment of the present invention, FIG. 1(A) is a longitudinal sectional view of the exhaust gas purification device, and FIG. 1(B) is a B- in Figure 1 (A)
2 is a vertical sectional front view of the upper part of the engine, FIG. 3 is a bottom view of the ceramic filter of the exhaust purification device for engine 7 according to the second embodiment, and FIG. 4 is the conventional technology 1. FIG. 4 (
A) is a diagram equivalent to Figure 1 (A), and Figure 3 (B) is a diagram equivalent to Figure 4 (A).
), and FIG. 5 is a diagram for explaining an engine exhaust purification device according to Prior Art 2, and FIG.
is a diagram equivalent to Figure 1 (A), and Figure 5 (B) is a diagram equivalent to Figure 5 (A,
) is a sectional view taken along line BB. 1...Engine, 2...Exhaust purification chamber, 3. Exhaust passage, 4. Ceramic filter, 5. Exhaust flow passage.
6... Exhaust inlet of 5, 7... Diversion chamber, 8... Exhaust outlet of 5, 9... Merging chamber, 10... One end closed path, 11...
Both ends open passage, 12... Exhaust inflow passage, 13... Filter wall, 14... Exhaust outlet passage, 29... Starting end face of 4, 30... Exhaust introduction passage.

Claims (1)

[Claims] 1. An exhaust purification chamber 2 of the engine 1 is interposed in an exhaust passage 3, a ceramic filter 4 is housed in the exhaust purification chamber 2, and the ceramic filter 4 forms a plurality of exhaust flow passages 5 therein. The exhaust inlet 6 of each exhaust flow passage 5 is opened facing the branching chamber 7 on the inlet side of the exhaust gas purification chamber 2, and the exhaust outlet 8 is opened in the merging chamber 9 on the outlet side. In the exhaust gas purification device for an engine, which is configured to open toward the front, the exhaust flow passage 5 has a closed passage 10 at one end and an open passage 11 at both ends. The exhaust inflow path 12 has an exhaust inlet 6 at its starting end and is closed at its terminal end. The starting end is closed and an exhaust outlet 8 is formed at the terminal end, and the both-end open passages 11 are configured by forming the exhaust inlet 6 at the starting end and the exhaust outlet 8 at the terminal end. The exhaust inlets 6 of the plurality of both-end release passages 11 are opened near the center of the starting end surface 29, and
This engine exhaust purification device is characterized in that exhaust inlets 6 of a plurality of exhaust inflow paths 12 are opened in the periphery thereof, and an exhaust inlet path 30 is tangentially communicated with a separation chamber 7.