JPH022890Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present application relates to an exhaust particulate separator used in the exhaust system of an internal combustion engine, particularly a diesel engine.

The particulates in the exhaust mainly consist of submicron-order carbon particles. Therefore, in order to separate and remove this, a filter having a fine heat-resistant material is used. However, such a filter causes premature clogging and cannot withstand long-term use. Therefore, in addition to such a filter, an exhaust particulate separation device has been proposed which is further provided with a filter regeneration means. The regeneration means is a heating device that heats the filter clogged with carbon particles to burn out the carbon particles and restore the filter function. Heating in that case is done by a fuel burner. The fuel burner is
It is superior to heating devices such as electric heaters in that it can reliably obtain high temperatures, and is in practical use.

As shown in FIG. 1, a conventional exhaust particulate separator is comprised of a filter 2 provided downstream of an exhaust pipe 1 and a fuel burner 4 provided in front of an inlet surface 3 of the filter. Furthermore, an auxiliary air supply pipe 5 is provided near the fuel burner 4 . This device uses a fuel burner 4 that injects and ignites fuel when the filter 2 is clogged with carbon particles.
is activated to heat the filter 2 and burn out the captured carbon particles.

By the way, in order to improve the filter regeneration using such a device, the fuel burner 4 needs to satisfy the following requirements. First, the rotation must be uniform to prevent the filter 2, which is made of heat-resistant material, from being unevenly heated and damaged by thermal distortion. Second, the fuel burner 4 must be able to burn stably even when the operating state of the engine (engine speed, etc.) changes. In order to meet these requirements, as shown in FIG. 2, an auxiliary air supply pipe 5 is provided in the tangential direction to swirl the auxiliary air, and a fuel guide pipe 7 is provided in front of the fuel injector 6. The inventors of the present invention have proposed a fuel burner 4 consisting of:

However, this method is insufficient in the following points. In other words, the fuel injected from the injector 6 may form relatively coarse droplets due to the atomization adhering to the fuel guide pipe and agglomeration, or due to incomplete atomization from the beginning. As a result, the concentration of the injected fuel becomes uneven, and only the surface of the droplet burns, or the droplet-shaped fuel is burned during a fire. It is also difficult to burn, resulting in uneven combustion and heating.

In view of the above, the present application provides a heat-resistant filter in the exhaust pipe, a guide tube around the nozzle of the fuel injector in front of the filter, and a guide plate with an inverted L-shaped cross section in front of the tip of the guide tube. Furthermore, by arranging a fuel burner with a burner tube around the guide tube and installing an ignition device inside the burner tube, the fuel from the fuel injector burns in the form of coarse droplets. It is designed to prevent this from happening and to bring about stable and uniform combustion.

To describe an embodiment, FIG. 3 shows an exhaust particulate separator 10 of the present invention, in which a fuel burner 12 and a filter 13 are sequentially arranged in an exhaust pipe line 11. The filter 13 is made of ceramic, which is a heat-resistant material, and has a so-called honeycomb shape or a three-dimensional mesh shape. As another example, it may be made of metal mesh. fuel burner 12
The burner tube has a guide tube 16 provided around the nozzle of the fuel injector 14 with an open tip, and a burner tube 17 connected to the outside of the guide tube 16 with one end closed and the other end open. The other open end of the cylinder 17 is open to the exhaust pipe line 11 and the filter 13 is opened to the exhaust pipe line 11.
located facing the In front of the tip of the guide tube 16, a partition plate 18 connected to the guide tube is provided. The cutting plate 18 has an almost inverted L cross section.
The horizontal part 18a is located between the bottom surface of the guide cylinder 16 and the burner cylinder 17, and the vertical part 18b is located so as to block the open tip of the guide cylinder 16. are doing. A swirling flow forming means, for example, an auxiliary air pipe 20 provided tangentially to the side wall near the closed end is attached to the burner cylinder 17. Another swirling flow forming means is one in which swirling vanes are provided at the closed end of the burner cylinder 17. An ignition device 19 is provided within the burner cylinder 17, and the ignition device 19 is, for example, a glow or a spark plug. Further, the fuel injector 14 may be one for high pressure or one for low pressure.

The exhaust particulate separator 10 is connected to an exhaust manifold of a diesel engine and put into use.

The exhaust gas containing carbon particles passes through the exhaust pipe 11 to reach the inlet surface 13a of the filter 13, further flows through the filter 13, and is discharged to the atmosphere. Carbon particles are captured while flowing through the filter 13. When the filter 13 reaches a predetermined clogging state, the ignition device 19 is ignited and the fuel injector 14 is started by means (not shown) that senses and operates the differential pressure across the filter 13, for example. At the same time, auxiliary air is introduced into the burner cylinder 17 from the auxiliary air pipe 20. fuel injector 1
The fuel injected from the nozzle 15 of No. 4 stays in the guide cylinder 16 in the form of mist or droplets, or collides with the partition plate 18 and scatters. Auxiliary air pipe 2
The auxiliary air from 0 becomes a swirling flow, circulates inside the burner cylinder 17, and mixes with the injected fuel. When the igniter 19 is ignited, this mixture ignites and burns. The combustion flame at this time becomes relatively homogeneous due to the guide tube 16 and the swirling flow, mixes with the exhaust gas, and increases the exhaust temperature, thereby heating the filter 13 uniformly. When the temperature of the filter 13 reaches a predetermined temperature or higher, the carbon particles captured by the filter 13 are burned and burned away, and the filter 13 is regenerated to restore its function. When the differential pressure created by the filter 13 decreases, both the fuel supply and the auxiliary air supply to the fuel burner 12 are stopped. In addition, the auxiliary air is
It is also possible to allow the fluid to flow continuously during operation, regardless of whether or not the filter 13 is clogged. In addition, if a through hole is provided in the burner cylinder 17, auxiliary air,
Mixing of fuel and exhaust is facilitated.

In the above, the fuel injected from the fuel injector 14 is caused by the agglomeration of the atomized fuel itself, or by the fact that the fuel injected from the fuel injector 14 is mixed with the partition plate 18 and the guide cylinder 1.
There is a risk that the filter 13 will be coarsened by colliding with the particles 6 and agglomerating, stopping combustion, making the combustion state uneven, and heating the filter 13 unevenly, but this risk can be eliminated as follows. That is, as described above, the fuel from the fuel injector 14 aggregates,
The particles become coarse, but at that time they fall onto the horizontal portion 18a of the partition plate 18 and are collected there. On the other hand, since the partition plate 18 is heated by combustion, the fuel accumulated in the horizontal part 18a of the partition plate 18 evaporates and remains in the burner cylinder 17 in an atomized state.
This leads to even more homogeneous combustion.

As described above, the present invention provides a filter in the exhaust pipe line and a fuel burner consisting of a burner cylinder equipped with a fuel injector, a guide cylinder, an ignition device, and a swirl flow forming means in front of the filter. In the separation device, in front of the guide tube,
The inverted L-shaped cross section prevents the fuel injected from the injector from becoming small droplets, which would result in uneven or unstable combustion, and evenly heats the filter.
The filter function can be effectively regenerated.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional device, FIG. 2 is a sectional view of a burner, and FIG. 3 is a sectional view of the device of the present invention. 12...Fuel burner, 13...Filter, 14
...Fuel injector, 18...Instruction plate.

Claims (1)

[Scope of utility model registration request] A heat-resistant filter is provided in the exhaust pipe, and in front of the filter is provided a guide tube whose tip is open around the nozzle of the fuel injector, and in front of the tip of the guide tube is a guide plate with an inverted L-shaped cross section. A fuel burner is provided on the outer periphery of the guide tube, and includes a burner tube having one end closed and the other end open and having an auxiliary air swirling flow forming means on the wall surface, and an ignition device disposed inside the burner tube. Exhaust particulate separator consisting of: