JPH0227130Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to an apparatus for treating exhaust particulates such as carbon or particulate contained in the exhaust gas of an internal combustion engine.

<Prior Art> The present application is an exhaust particulate treatment device for an internal combustion engine that prevents exhaust particulates such as carbon and particulate contained in the exhaust of an internal combustion engine such as a diesel engine from being released into the atmosphere. The person proposed the patent application No. 57-201825 first.

This is constructed as shown in Figs. 1 to 4, and a part of the exhaust passage 2 that discharges the exhaust gas from the internal combustion engine 1 into the atmosphere collects exhaust particulates contained in the exhaust gas. By installing a trap 3 and providing a burner device (hereinafter referred to as burner) 4 upstream of the trap 3, the trap 3 collects exhaust particulates contained in the exhaust gas, and also collects exhaust particulates in an arbitrary set amount. When the burner 4 is collected, the burner 4 is operated, and the trap 3 is regenerated by heating and incinerating the exhaust particulates with the heat of the flame generated as a result of this operation.

In addition, fresh air (air) is supplied to the burner 4 from an air pump 5 driven by an engine via a switching valve 7 driven by a vacuum pump 6, and fuel is supplied from an injector 8. still,
Fresh air and fuel are mixed while passing through the mixture introduction pipe 9 and the fuel is atomized to some extent, and the upstream end of the bottomed cylindrical evaporator cylinder 10 that surrounds the outer periphery of the outlet of the mixture introduction pipe 9 in the burner 4 The air-fuel mixture is ejected from the main ejection port 11 formed on the circumferential surface of the air-fuel mixture.

Near the evaporator cylinder 10, there is a type of glow plug 1 whose tip, which has excellent temperature-raising characteristics, is concentrated and becomes red-hot.
2, and the evaporator 10 is also provided with an auxiliary ejection port 13 on the side wall facing the glow plug 12. As fuel and fresh air are supplied, the mixture is introduced into the evaporator tube 10, and the fuel is vaporized by contact with the evaporator tube 10, which is heated by the exhaust heat. Ignition occurs when the air-fuel mixture is ejected from the auxiliary ejection port 13 and comes into contact with the glow plug 12, which has been sufficiently heated to a high temperature by applying a voltage in advance, from directly above. Thereafter, the flame generated by this ignition flows out of the glow cover 14 provided to keep the glow plug 12 warm, and the main ejection port 11 opens on the side wall upstream from the auxiliary ejection port 13. The air-fuel mixture ejected from the burner 4 is ignited, and combustion in the burner 4 is started. In addition, the glow plug 12 has
Even after ignition as described above, voltage application continues for several seconds until combustion stabilizes, and then stops.

Also, the air pump 5 that supplies fresh air is connected to the internal combustion engine 1.
While the burner 4 is in operation, it continues to operate and send out fresh air, but only when the burner 4 is burning, fresh air is supplied to the mixture introduction pipe 9 via the switching valve 7, and when the burner 4 is extinguished (when stopped). ) prevents the glow plug 12, evaporator 10, etc. from being cooled by fresh air that is guided from the switching valve 7 to the atmosphere or upstream of the air cleaner 15, and prevents ignitability caused by a decrease in temperature. Prevent deterioration. Reference numeral 16 denotes a conical frame holder that covers the mixture introduction pipe 9, the evaporator tube 10, the glow plug 12, etc. from the upstream side.

However, in such a conventional exhaust particulate treatment device, a part of the glow plug 12 that performs the ignition operation of the burner 4 is directly exposed to the flame accompanying the combustion of the burner 4 after ignition, and even after ignition, combustion continues. Since the voltage was applied for several seconds until the glow plug 12 stabilized, the temperature of the glow plug 12 reached a high temperature of, for example, over 1300°C, reaching the limit in terms of durability and burning out over time. When I put it away, I ran into a problem.

<Purpose of the invention> The present invention was made to solve these conventional problems, and its purpose is to improve the durability of the glow plug without adversely affecting the ignition performance of the burner device. There is.

<Structure of the invention> In order to achieve the above object, the present invention includes a mixture introduction pipe provided at the upstream part of a trap installed in the exhaust passage of an internal combustion engine, and a material surrounding the outer periphery of the mixture introduction pipe outlet. It has an evaporator cylinder with a cylindrical bottom, a semi-cylindrical glow cover with a bottom fixed to the side surface of the evaporator cylinder, and a glow plug whose tip is inserted into the glow cover, and the auxiliary outlet is connected to the evaporator cylinder. A conical cone that is opened in the side wall facing the glow plug, the main jet port is opened in the side wall upstream of the auxiliary jet port of the evaporator cylinder, and that covers the mixture introduction pipe, the evaporator cylinder, the glow plug, etc. from the upstream side. a shaped frame holder;
In the burner device having a glow plug, a fire prevention wall covering at least a part of the upstream side of the glow plug is provided to prevent the flame of the burner device generated after ignition from coming into direct contact with the glow plug. This reduces the heat load on the glow plug and prevents burnout of the glow plug.

<Example> The example shown in FIGS. 5 to 8 will be described below. Note that parts having the same functions as those of the conventional example shown in FIGS. 1 to 4 are designated by the same reference numerals, and their explanations will be omitted.

5 and 6 show an embodiment of the present invention, in which a cross-sectional half covering the upstream half of the glow plug 12 is installed downstream of the main air-fuel mixture outlet 11 and upstream of the glow plug 12. By providing the circular firewall 17, the flame caused by the air-fuel mixture ejected from the main ejection port 11 is prevented from coming into direct contact with the glow plug 12. Also, by opening the downstream half of the glow plug 12, the auxiliary jet nozzle 13 can be opened.
The flame caused by the air-fuel mixture ejected from the main ejection port 11 is made to easily ignite the air-fuel mixture ejected from the main ejection port 11.

Therefore, in the exhaust particulate treatment device configured as described above, the glow plug 12 is sufficiently heated by voltage application during the trap regeneration period, and the mixture inlet pipe is heated in a state where the glow plug 12 is concentrated and red hot at its tip. The air-fuel mixture is introduced into the evaporator cylinder 10 from 9. Here, the glow cover 14 connects the exhaust flow to the evaporator tube 10.
the air mixture introduced into the glow plug 1
2 is provided to cover the red-hot part. Moreover, since this evaporator cylinder 10 is heated and maintained by exhaust heat, the liquid fuel contained in the air-fuel mixture introduced as described above is vaporized by contact with the evaporator cylinder 10 and becomes fresh air. Mix thoroughly. Then, it flows into the interior of the glow cover 14 through the auxiliary spout 13, and is ignited by contact with the glow plug 12, which has been sufficiently heated as described above. That is, in the inner space of the glow cover 14, the inner wall of the glow cover 14 is at a high temperature due to the red-hot glow plug 12, and when the vaporized fuel comes into contact with the inner wall, ignition occurs immediately and combustion starts. This creates a space where it is easy to ignite.

After ignition, this flame flows out from the glow cover 14, ignites the air-fuel mixture flowing out from the main jet port 11, and starts combustion.
The tip that should become red hot is covered by the glow cover 14, and the upstream half of the glow plug 12 other than the tip is covered by the fire wall 17 as described above, so the flame caused by this combustion comes into direct contact with the glow plug 12. Never.

Note that after ignition, the glow plug 12 continues to be energized for several seconds until combustion becomes stable. Further, one end of the fire wall 17 is brought into contact with the glow cover 14, and the other end of the fire wall 17 is also brought into contact with the frame holder 16, thereby preventing the fire wall 17 from overheating.

7 and 8 show another embodiment of the present invention, in which the frame holder 1
A fire prevention wall 17 is constructed by making a part of the inner wall of the evaporator 6 protrude in a cylindrical shape toward the evaporator cylinder 10 . The glow plug 12 is housed in the center of the fire wall 17 to prevent the glow plug 12 from being exposed to flame, and a gap 18 is secured between the tip of the fire wall 17 and the glow cover 14. In this way, the air-fuel mixture ejected from the main ejection port 11 is easily ignited. Furthermore, by ensuring a gap sufficient for exhaust gas to flow between the outer peripheral surface of the glow plug 12 and the inner peripheral surface of the fire wall 17, overheating of the fire wall 17 exposed to the flame is avoided. However, the specific structure of the firewall 17 is not limited to the example.

<Effects of the Invention> As explained above, according to the present invention, a fire wall covering at least a part of the upstream side of the glow plug is provided to suppress direct contact of the flame caused by combustion in the burner device with the glow plug. When the burner device is activated (during combustion),
The heat load on the glow plug can be significantly reduced, and burnout of the glow plug due to overheating can be avoided and the durability of the exhaust particulate treatment device can be improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of a specific example of an exhaust particulate treatment device for an internal combustion engine to which the present invention is applied, Fig. 2 is a sectional view of main parts of a conventional example, Fig. 3 is a front view of Fig. 2, and Fig. 4 The figure is a sectional view of FIG. 2, FIG. 5 is a front view of the main part of an embodiment of the present invention, and FIG.
FIG. 7 is a front view of essential parts showing another embodiment of the present invention, and FIG. 8 is a cross-sectional view taken from FIG. 7. 1... Internal combustion engine, 2... Exhaust passage, 3... Trap, 4... Burner device, 12... Glow plug, 17... Fire wall.

Claims (1)

[Scope of utility model registration request] A mixture inlet pipe installed at the upstream part of a trap installed in an exhaust passage of an internal combustion engine, a bottomed cylindrical evaporator tube surrounding the outer periphery of the outlet of the mixture inlet tube, and a metal fixed to the side surface of the evaporator tube. It has a semi-cylindrical bottom glow cover and a glow plug whose tip is inserted into the glow cover, the auxiliary jet opening is opened in the side wall facing the glow plug of the evaporator cylinder, and the main jet opening is opened in the side wall of the evaporator cylinder facing the glow plug. A burner device including a conical frame holder that is opened in a side wall upstream of the auxiliary jet nozzle and that covers the mixture introduction pipe, evaporator tube, glow plug, etc. from the upstream side, at least upstream of the glow plug. An exhaust particulate treatment device for an internal combustion engine, characterized in that a fireproof wall covering a part of the side is provided.