JPS6065219A - Particulates trap in internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent a crack in a trap while excessive accumulation of particulates due to a lapse of time, by dividing the trap into plural parts with respect to the face in a flow path direction further providing an optional clearance in said divided face so as to form a release space from thermal expansion of the trap. CONSTITUTION:Exhaust, allowed to flow in inlet side opening cells 9A and pass through a porous thin wall 8 and through a neighboring outlet opening cell, is discharged to the downstream side of a trap 10. Here particulates are collectively caught by the porous thin wall 8, but the particulates, if its amount exceeds a certain value, is burnt by a burner, reproducing the trap 10. A crack can be prevented from its generation because a trap 10A and a trap 10B, even if they are thermally expanded by combustion heat when the trap is reproduced, are absorbed by a clearance 11. While a pressure rise of exhaust in the upstream of the trap 10 can be prevented because the exhaust is mostly discharged through the clearance 11 if an accumulation amount of the particulates increase above a certain value.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a trap for removing particulates contained in the exhaust gas of an internal combustion engine.

<Prior Art> Examples of conventional particulate traps for internal combustion engines include those shown in FIGS. 1 to 3. (Reference document: Japanese Unexamined Patent Publication No. 49-38266) FIG. 1 shows a system diagram integrated with a burner section 1 for regenerating particulates collected by a trap 2.

That is, in the figure, inside the case 3 of the trap 2, a large number of air permeable porous thin walls 4 are arranged in parallel to the exhaust flow direction, and a large number of Cefivs 5 are assembled in a lattice shape. The exhaust inlet side open end and the outlet side open end of each cell 5 are alternately sealed 6. Further, the trap 2 is supported around the periphery with wire mesh or the like, and is backed within the case 3.

In addition, FIG. 2 shows the cross section A-A' shown in FIG. 1 viewed from the upstream to the downstream direction of the Choyu-ryu, and FIG. 3 shows the details of the lattice-like portion.

Next, its effect will be explained.

The exhaust gas that has flowed into the trap 2 flows into the cell 5A whose inlet side is open. Since the open end of the cell 5A on the outlet side is sealed, this exhaust gas flows out through the porous thin wall 4 into the adjacent cell 5B, which has an open exhaust outlet side, and is discharged to the downstream side of the trap 2. At this time, particulates contained in the exhaust gas are collected by the porous thin wall 4 and accumulated on the exhaust gas inflow side wall surface.

However, in such conventional particulate traps, the trap 2 is held by wire mesh or the like and backed inside the case 3 without any gaps, so if the trap 2 thermally expands during regeneration by the burner 1, the trap circle will change. There was no space for escape in the circumferential direction (there was a problem that cracks would occur due to internal strain).Furthermore, the exhaust inlet and outlet sides were made of porous thin walls 4 and plugs 6. Because the structure was completely partitioned by The residual exhaust amount increases and the exhaust flow resistance increases.As a result, 2.
Deteriorates engine performance and emission performance. Furthermore, when the trapped particulates are burned to regenerate the trap, a large amount of particulates burns and rapidly generates heat, which can cause cracks and melting damage to the internal body of the trap 2, which may impair the function of the trap 2. will be damaged.

For this reason, it is necessary to incinerate the particulates collected at very short time intervals in the burner section 1, etc.
This causes a very large loss in fuel consumption, and also increases heat loss as the frequency of incineration increases, resulting in problems such as a decrease in the durability of the trap 2.

<Object of the invention> This invention was made by focusing on the above-mentioned conventional problems, and when regenerating a trap with a burner,
Provide an escape space for the thermal expansion of the trap, and prevent excessive accumulation of particulates over time.
Therefore, it is an object of the present invention to solve the above-mentioned problems by suppressing the exhaust pressure on the upstream side of the trap and the rate of increase in exhaust pressure to a low level.

<Structure of the Invention> Therefore, in the present invention, the trap is divided into a plurality of parts along the plane in the direction of the flow path, and an arbitrary gap is provided in the divided plane, and the gap serves as an escape for the thermal expansion of each divided trap. The structure is such that a part of the exhaust flow flows through the nuclear gap.

Embodiments Examples of the present invention will be described below with reference to FIGS. 4 and 5.

In FIG. 4, a horizontally oblong oval structure is constructed by assembling a large number of cells 9 in a lattice shape with a porous thin wall 8 having air permeability disposed parallel to the flow direction of exhaust gas discharged from the engine. The trap 10 is divided into left and right halves on a vertical plane passing through the center of the trap in the direction of the flow path.

t1 I −＾Δ Senseki day n−L 7, slfA Senji φ, there is an arbitrary gap 1 between the wrap 10A and the trap 10B.
1 is provided.

Incidentally, at the upper and lower ends of this gap 11, a cushioning material 12 is interposed as a holder for holding the gap 11, which can alleviate the impact applied between the traps 10A and 100 and absorb thermal expansion. do.

Next, the effect will be explained.

The exhaust gas containing particulates emitted from the engine is
It flows into the inlet side open cell 9A of the trap 10 and the gap 11 between the divided traps IOA and 10B. Of these, the exhaust gas that has flowed into the inlet-side open cell 9A passes through the porous thin wall 8, passes through the adjacent outlet-side open cell, and is discharged to the downstream side of the trap 10. At this time, as in the conventional case, particulates in the exhaust gas are collected and accumulated on the surface of the porous thin wall 8 on the exhaust gas inlet side. When the amount of trapped particles exceeds a certain value, the burner 1 burns the particulates and the trap 10 is regenerated. Even if the traps 10A and 10B thermally expand due to combustion heat during regeneration, the gap 1
Because it is absorbed in the space by 1.

No excessive force is applied to the trap 10A,) the lamp IOB, no distortion occurs, and cracks can be prevented.

On the other hand, the exhaust gas that has flowed into the gap 11 is directly discharged from the open outlet. As the amount of particulates collected and accumulated on the surface of the porous thin wall 8 of the inlet-side open cell 9A increases, the pressure loss in this area increases, so that the exhaust gas passes through the gap 11. When the rate of exhaust gas increases and the amount of birch cumulate collected exceeds a certain value, most of the exhaust gas will be exhausted through one gap 11.

Therefore, with this configuration, even if one engine is operated for a long time, the amount of accumulated particulates and pressure loss due to the trap 10 can be suppressed to below a certain amount, and the trap 10
The exhaust pressure on the upstream side and the rate of increase in exhaust pressure can be kept low. As a result, good engine performance and emission performance can be maintained.

Also, when the trap 10 is regenerated, excessive heat generation due to combustion of a large amount of particulates is suppressed, and damage and melting of the trap 10 can be prevented. Furthermore, the regeneration interval by the burner section etc. can be made longer, and fuel efficiency and durability can be significantly improved.

In the above embodiment, the trap 1G is divided into two along the vertical flow path direction passing through the center, but the invention is not limited to this. What is necessary is to divide it into pieces and create a structure in which gaps are provided between the divided surfaces.

FIG. 5 shows another embodiment of the present invention, in which the trap 10 is used as a cushioning material 13 for absorbing and mitigating the impact or thermal expansion applied between the traps IOA and 10B.
A part of the cushion material 7, such as wire mesh, interposed between the case 3 and the case 3 is folded. By doing this, another cushion material 1 as in the embodiment shown in FIG.
2 is not newly provided, and is practical.

<Effects of the Invention> As described above, according to the present invention, the trap is divided into a plurality of traps and gaps are provided between each divided trap, so when the trap is regenerated by burning particulates with a burner, the trap is regenerated by the heat of combustion. The thermal expansion of the trap can be absorbed by the gap, thereby preventing the occurrence of bulges. moreover,
Since a part of the exhaust flow is configured to flow through the gap, excessive accumulation of particulates over time can be prevented, and the amount of accumulated particulates and pressure loss in the trap can be suppressed to a certain amount or less. The exhaust pressure and the rate of increase in exhaust pressure can be kept low. Therefore, engine output is improved, fuel efficiency is improved, and long-term operation is possible without deteriorating drivability. Additionally, if a device is installed that regenerates the trap by incinerating the collected particulates, it is possible to suppress excessive heat generation due to particulate combustion and reduce the number of operations, resulting in improved fuel efficiency and durability. surface can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an example of a conventional particulate trap in an internal combustion engine, and FIG.
k th1%NM whistle Q 1iyl 4+ rfl k
Fig. 4 is a longitudinal sectional view showing one embodiment of the particulate trap for an internal combustion engine according to the present invention, and Fig. 5 is a detailed view of the lattice-like part in It is a longitudinal cross-sectional view of the same as the above showing an example. 8...Porous thin wall 9...Cell 10, 10A,
10B...Trap 11...Gap patent applicant Nissan Motor Co., Ltd. agent Patent attorney Fujio Sasashima

Claims (1)

[Claims] A large number of cells are assembled in a lattice shape by arranging a porous thin wall with air permeability parallel to the flow direction of the exhaust gas discharged from the engine, and the open end on the exhaust inlet side and the open end on the exhaust outlet side of adjacent cells are formed. By alternately closing the cells one at a time and allowing the exhaust gas flowing in from the cell on the open side of the exhaust inlet to pass through the porous thin wall to the adjacent cell on the open side of the exhaust outlet, the exhaust gas inflow into the porous thin wall is In a particulate trap for an internal combustion engine that filters and collects particulates contained in the exhaust gas, the particulate trap is divided into a plurality of traps along the plane in the direction of the flow path, and an arbitrary gap is provided on the divided plane. A particulate trap for an internal combustion engine, characterized in that a particulate trap for an internal combustion engine is used as an escape space for thermal expansion of the trap.