JPH0455217Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present application relates to an exhaust particulate separator used in the exhaust system of an internal combustion engine, particularly a diesel engine.

[Conventional technology]

The particulates in the exhaust mainly consist of submicron-order carbon particles. Therefore, in order to separate and remove this, a filter having a heat-resistant material with fine mesh is used. However, such filters cause 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. Fuel burners are superior to heating devices such as electric heaters in that they can reliably obtain high temperatures, and are in practical use.

As shown in FIG. 3, the conventional exhaust particulate separator includes a fuel burner 12 provided in front of the inlet face of a heat-resistant filter 11 disposed in the middle of an exhaust pipe, and facing the filter 12; It consists of an exhaust pipe 13 bent into an L-shape at the burner 12. The fuel burner 12 includes a fuel guide cylinder 15 and a shielding plate 16 arranged around the nozzle of the fuel injector 14, and an auxiliary air supply pipe 1 on the fuel burner closed side.
7 is provided in the connection direction. In this device, when a filter 11 is clogged with carbon particles, a fuel burner 12 is activated to inject and ignite fuel, and auxiliary air uses a swirling flow to even out the heat, heat the filter, and burn the captured carbon particles. , and are now being burnt down.

[Problem that the invention attempts to solve]

However, this method is insufficient in the following points. That is, exhaust pipe 1
3 is bent into an L-shape in front of the filter 11, and the fuel burner 12 is built into the bent portion, so the flame of the fuel burner 12 and the exhaust gas reach the filter before being sufficiently mixed, resulting in high-temperature combustion. A portion of the high-temperature exhaust gas that entrains the gas mainly heats the central portion of the filter 11, burns out the heated portion, and lowers the ventilation resistance. Then, the exhaust gas begins to flow toward the area with less ventilation resistance, and filter 1
This deteriorates the temperature distribution of the exhaust gas relative to the filter 11, resulting in an uneven heating state, and it takes time to regenerate the filter 11. Furthermore, there was a risk that the filter 11 would be damaged due to uneven heating.

[Means for solving problems]

In the present application, a heat-resistant filter is disposed in an exhaust pipe line, the pipe line on the upstream side of the filter is narrowed, and a mixing chamber with a circular cross section is formed perpendicular to the filter, and the circular mixing chamber The exhaust pipe was tangentially connected to the fuel burner, and the opening of the fuel burner, which was open at one end, was installed along the swirling direction of the exhaust gas in the exhaust pipe in the circular mixing chamber.

[Effect]

When the filter becomes clogged with carbon particles, the flame of the activated fuel burner is injected in the flow direction of the swirling flow of exhaust gas swirling in the mixing chamber, and the flame flows into the mixing chamber from the exhaust inlet path. The incoming exhaust gas is heated to a high temperature and reaches the filter while swirling from the center of the mixing chamber, heating the entire surface of the filter evenly and continuously.

〔Example〕

FIG. 1 shows an exhaust particulate separator 1 according to the present invention, in which a mixing chamber 4 equipped with a fuel burner 3 and a filter 5 are sequentially arranged in an exhaust pipe line 2. The filter 5 is made of ceramic, 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. The fuel burner 3 has a burner tube 33 that is connected to the outside of the nozzle of the fuel injector 31 and has one end closed and the other end open, and the other open end of the burner tube 33 is connected to the mixing chamber 4 described later. It is open to the public. An ignition plug 34 and a shielding plate 35 are provided in front of the tip of the nozzle. Also, burner tube 33
A swirling flow forming means, for example, an auxiliary air supply pipe 36 provided tangentially to the side wall near the closed end is attached to. The circular mixing chamber 4 is located in front of the filter 5 and forms part of the exhaust pipe 2, and the central portion 41
and the inlet portion of the filter 2 are in communication. The mixing chamber 4 has a circular cross section, is provided with an exhaust pipe which is tangentially discharged from the internal combustion engine, and has a fuel burner 3 mounted at an angle with respect to the exhaust pipe.

Carbon particles generated by the operation of the internal combustion engine flow together with the exhaust gas through the exhaust pipe 2, pass through the circular mixing chamber 4, and are captured by the filter 5. When the filter 5 becomes clogged and the back pressure increases, the ignition plug 34 is heated in response to an instruction from a sensor (not shown), receives fuel from a fuel supply source, for example, a fuel tank, and injects it while atomizing it from the nozzle of the fuel injector 31. They are scattered by shielding plates 35 and ignited by spark plugs 34, and auxiliary air is sent into the burner cylinder 33 to form a swirling flow to grow flames and generate high temperatures to burn the carbon particles. fuel burner 3
The high-temperature combustion gas is released into a swirling flow of exhaust gas in the circular mixing chamber 4, and is thoroughly mixed during the swirling to become high-temperature exhaust gas at the center 41 of the circular mixing chamber 4.
It flows toward the filter 2 while maintaining a swirling flow, and the entire surface of the filter 2 is uniformly heated and burnt out, thereby regenerating the filter.

〔effect〕

As described above, the present invention provides a circular mixing chamber perpendicular to the filter in front of the filter installed in the exhaust pipe, connects the exhaust pipe tangentially to the circular mixing chamber, and connects the exhaust pipe to the fuel burner. Since the opening is installed along the swirling flow inside the circular mixing chamber, the exhaust gas flowing into the circular mixing chamber from the exhaust pipe is heated to a high temperature by the flame of the fuel burner, and is thoroughly mixed in the swirling flow inside the circular mixing chamber. can do. Furthermore, since the outlet of the circular mixing chamber is narrowed and high heat is uniformly applied to the entire surface of the filter, the time required for filter regeneration can be shortened.

[Brief explanation of drawings]

FIG. 1 shows an exhaust particulate separator according to the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 shows a conventional exhaust particulate separator. 2... Exhaust pipe line, 3... Fuel burner, 4... Circular mixing chamber, 5... Filter.

Claims (1)

[Scope of utility model registration request] A heat-resistant filter is disposed in the exhaust pipe, a circular mixing chamber with a circular cross section is formed on the upstream side of the filter and perpendicular to the filter, and the exhaust pipe between the filter and the circular mixing chamber is throttled. and an exhaust pipe line is tangentially connected to the circular mixing chamber,
An exhaust particulate separator in which the opening of a fuel burner with one end open is installed in a circular mixing chamber along the direction in which exhaust gas swirls through an exhaust pipe.