JPH0137141Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an exhaust particulate separation device for internal combustion engines, particularly diesel engines.

(Prior art) Particulates contained in the exhaust gas of internal combustion engines, especially diesel engines, are mainly composed of carbon, so they are captured and separated using a heat-resistant filter, and if the filter becomes clogged, the particulates are combusted. There is an exhaust particulate separator that removes the particles by For example, this is disclosed in Japanese Utility Model Application Publication No. 134613/1983. This burner has a cylindrical outer shape located upstream of a filter (trap) installed in the exhaust pipe, and inside this burner is a counterflow type evaporation cylinder consisting of a double cylinder of an inner cylinder and an outer cylinder. is provided. A fuel injection nozzle faces the inner cylinder 3 of the reverse flow type evaporator cylinder, and an ignition plug faces the outside of the inner cylinder inside the burner. An exhaust gas introduction hole is provided in the peripheral wall of the cylindrical burner. Since the downstream end of the outer cylinder is closed,
The fuel makes a U-turn from inside the inner cylinder, passes through the inside of the outer cylinder, and flows backward toward the upstream side. During this time, the fuel flows out from the upstream end of the outer cylinder to the outer periphery of the outer cylinder while vaporizing, and is combined with the exhaust gas led from the exhaust introduction hole. The mixture is ignited by a spark plug, combusted by excess oxygen in the exhaust gas, and passed through a filter (trap).
It is designed to incinerate carbon particles attached to the In order to prevent the nozzle from clogging with soot, this backflow type evaporator is installed surrounding the nozzle so that the nozzle does not come into contact with the exhaust gas.

(Problem to be solved by the invention) The burner for filter regeneration in the conventional exhaust particulate separator as described above evaporates the fuel coming out of the nozzle in the evaporator cylinder. In addition to requiring a heating device to apply heat, the inner cylinder and the outer cylinder form a U-turn path in order to ensure a distance corresponding to the time required for the injected oil droplets to evaporate. Then, the vaporized fuel that can be ignited changes direction and flows from the most upstream side of the burner to the downstream side again. In this method, the structure of the burner is complicated, the path for the fuel to ignite becomes long, and the supply of fuel to the ignition point tends to become unstable. In addition, after ignition, combustion is performed using excess oxygen in the exhaust gas, so the amount of oxygen supplied tends to fluctuate, making it difficult to adjust the amount of supplied fuel, resulting in unstable combustion and fluctuations in combustion temperature. Tend.

(Means for solving the problem) The exhaust particulate separator of this invention is provided with a heat-resistant filter in the exhaust pipe line, and a fuel injector nozzle is attached to the upstream closed end of the filter, and the downstream end is connected to the heat-resistant filter. An open burner cylinder is provided, and within the burner cylinder, a fuel guide pipe with both ends open coaxially with the axis of the nozzle, and an obstruction plate facing the open end on the downstream side thereof are provided, and between the fuel guide pipe and the obstruction plate. An ignition plug is provided, and an auxiliary air inlet provided with a swirl flow forming means is further provided on the peripheral wall of the burner cylinder on the upstream side.

(Function) The exhaust particulate separator of this invention captures and separates particulates in the exhaust using a heat-resistant filter. When the filter becomes clogged, fuel is injected from the fuel injector, fresh air flows from the auxiliary air inlet, and the spark plug is activated.

Fuel is injected from the nozzle and travels straight to the obstacle plate. During this time, you will be guided surrounded by fuel guide pipes,
In addition, since it is protected from the swirling flow of auxiliary air around its outer periphery, the jet from the fuel nozzle travels straight without being disturbed and reaches the obstruction plate. The oil droplets in the jet become small droplets and atomize by colliding with the obstruction plate, turning around and spreading out, which is then ignited by the spark plug placed between the downstream end of the fuel guide pipe and the obstruction plate. . The ignited fuel enters from the auxiliary air inlet and is mixed with the fresh air that swirls between the inner periphery of the burner cylinder and the outer periphery of the fuel guide pipe by the swirling flow forming means, and burns to generate a flame. . Therefore, the flame travels from the downstream side of the outer periphery of the fuel guide pipe to the open end on the downstream side of the burner cylinder, and further reaches the filter, incinerating carbon particles and the like adhering to the filter. Since the flame reaches the filter in a swirling flow, the heating of the filter becomes uniform and the above-mentioned incineration is performed uniformly. In addition, due to the action of the swirling air flow, the pressure near the outer circumferential wall of the fuel guide pipe becomes slightly lower than that near the inner wall of the burner cylinder, so the fuel reversed by the obstacle plate tends to be attracted to the outer circumference of the fuel guide pipe. There was also a flame,
The temperature of the fuel that continues to travel straight inside the tube increases, and atomization is promoted.

(Example) An example is shown in FIG. In an exhaust particulate separation device 1 for a diesel engine, a heat-resistant filter 3 is installed between an exhaust pipe exhaust inlet 2 and an exhaust outlet 4. A burner device 5 for filter regeneration is provided upstream of the filter 3. The burner device 5 includes a burner cylinder 8 having an open downstream end facing the filter 3 and a closed upstream end to which a nozzle 9 of a fuel injector 6 is attached. Inside the burner cylinder 8, a fuel guide pipe 11 coaxial with the axis of the nozzle 9 and open at both ends, and an obstacle plate 10 facing the open end on the downstream side are arranged, and a spark plug is placed facing the gap D between them. 12 are provided. An auxiliary air inlet 7 is provided at one end of the peripheral wall on the upstream side of the burner cylinder 8, and by orienting the auxiliary air inlet 7 in the tangential direction of the burner cylinder, a swirling flow forming means is formed.

When the filter 3 becomes clogged with carbon particulates in the exhaust gas, it is detected by a clogging detection device (not shown), and fuel injection from the nozzle 9 of the fuel injector 6, air supply from the auxiliary air intake port 7, and spark plug are performed. Twelve ignition operations are performed. The fuel injected in the form of a jet from the nozzle 9 passes through the obstacle plate 10.
The flame is reversed, turned into small droplets and atomized, and ignited by the ignition plug 12, swirling and mixing with the air flowing down from the air inlet 7, forming a swirling combustion flame that reaches the filter 3, where it incinerates attached carbon particles, etc. do.

In another embodiment, the main part of which is shown in FIG. 2, a gap M is provided between the upstream open end of the fuel guide pipe 13 and the upstream closed end of the burner cylinder 8 to which the nozzle 9 is attached. The jet of fuel coming out of the nozzle 9 has a small spread angle such that it travels straight toward the obstacle plate, and in the part with the interval M, the fuel guide pipe 13
Since there is no need to restrict the direction of the jet flow, the distance M does not impede the action of the fuel guide pipe. On the other hand, in the case shown in Figure 2, a small portion of the air that enters the air inlet with the fuel jet is sucked in to the extent that it does not create a swirling flow and does not disturb the fuel jet, and when it reaches the obstruction plate, ignition occurs. encourage

(Effects of the invention) The exhaust particulate separator of this invention has a filter regeneration burner device in which a jet of fuel travels straight from the nozzle to the obstruction plate and is reversed to ignite.
The above jet stream is protected by a fuel guide pipe so that it is not disturbed by the swirling air flow, and the oxygen for combustion is supplied from fresh air rather than from exhaust gas, so it is necessary to install a fuel heating device in the pipe. The structure is simple, combustion is stable, and fine particles are reliably incinerated.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of this invention, and FIG. 2 shows a main part of another embodiment. 3... Filter, 6... Fuel injector, 7
... Air inlet, 8 ... Burner cylinder, 9 ... Nozzle, 10 ... Obstacle plate, 11, 13 ... Fuel guide pipe, 12 ... Spark plug.

Claims (1)

[Scope of utility model registration request] A heat-resistant filter is disposed in the exhaust pipe, and a burner cylinder having an open downstream end and a closed upstream end to which a fuel injector nozzle is attached is disposed upstream of the filter. An auxiliary air inlet having a swirl flow forming means is provided in the peripheral wall on the upstream side of the burner cylinder, a fuel guide pipe with both ends open coaxially with the nozzle axis in the burner cylinder, and an obstruction plate facing the open end on the downstream side. and an ignition plug facing between the downstream open end of the fuel pipe and the obstruction plate.