JP3341800B2 - DPF burner regeneration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DPF burner regenerating apparatus in an exhaust gas purifying apparatus for purifying exhaust gas discharged from an internal combustion engine such as a diesel engine.

[0002]

2. Description of the Related Art Conventionally, when purifying particulates (particulate matter) in exhaust gas of a diesel engine or the like, a diesel particulate filter (DPF) made of cordierite is attached to an exhaust system. DPF
The exhaust gas is purified by collecting the particulates on the surface of the exhaust gas.

When the DPF is used for a long time, particulates mainly composed of black smoke are deposited on the filter, and the back pressure of the engine is increased. Therefore, regularly burners,
It is necessary to perform a process of regenerating the DPF by raising the temperature by an electric heater or the like to burn and remove the accumulated particulates.

[0004]

Conventionally, as a DPF burner regenerating device in such an exhaust gas purifying device, one having the structure shown in FIGS. 2 and 3 is known. FIG.
The device has a structure in which a burner combustion chamber having a fuel injection nozzle and a spark plug is installed on the upstream side of the DPF, and a valve is provided at a connection between a passage connected to the DPF and the burner combustion chamber. The concentration of the particulates prevents the valve on the burner combustion chamber side from closing, thereby preventing the fuel injection nozzle and the spark plug of the burner combustion chamber from being contaminated with the particulates.

[0005] It is an essential condition that this valve has both sealing performance and heat resistance. Accordingly, an extremely expensive valve made of Inconel, Hastelloy or the like is used, so that there is a disadvantage that the cost is increased. Further, it is difficult to obtain perfect sealing even with such a valve made of a heat-resistant material, and often particulates adhere to the spark plug and the burner does not function. Further, there is a problem that thermal efficiency is deteriorated due to this structure, and incomplete combustion is likely to occur.

In the apparatus shown in FIG. 3, a burner combustion chamber having a fuel injection nozzle and a spark plug is installed upstream of the DPF, and combustion air is always supplied from the fuel injection nozzle simultaneously with the start of the internal combustion engine. Clogging and dirt on the spark plug are prevented. Further, since the burner combustion chamber is arranged near the DPF, the heat efficiency is good,
It can be completely burned.

This eliminates the disadvantages of the apparatus shown in FIG. 2, but requires a large amount of air at the same time as the start of the internal combustion engine, and requires a special air supply device (compressor) to operate. There was a drawback that it became expensive.

The present invention has been made to solve these problems, and prevents the fuel injection nozzle and the spark plug of the burner combustion chamber from being contaminated with particulates without using an expensive valve or a dedicated compressor. It is another object of the present invention to provide a DPF burner regenerating apparatus that can perform the above-described operations and has high combustion efficiency.

[0009]

In order to solve the above problems, the present invention relates to a DPF burner regenerating apparatus for regenerating a DPF disposed in a passage connected to an exhaust side of an internal combustion engine by a burner. A burner combustion chamber having a fuel injection nozzle and a spark plug is disposed upstream of the DPF, and a second DPF is disposed at a connection between the passage connected to the DPF and the burner combustion chamber. It is.

[0010] The DPF and the second DPF according to the present invention are:
It has a mesh-like vent hole inside and has a columnar shape as a whole. As the DPF and the second DPF,
For example, a porous silicon carbide sintered body, cordierite or the like can be used, and a porous silicon carbide sintered body is preferable.

The DPF and the second DPF according to the present invention are:
Although the structure is the same as described above, the DPF has a function of purifying exhaust gas, while the second DPF has a function of preventing the inflow of particulates into the burner combustion chamber. Is preferably suitable for its function.

[0012]

In the DPF burner regenerating apparatus of the present invention, the second DPF having the same structure as the DPF is disposed at the connection between the passage connected to the DPF and the burner combustion chamber. Particulates can be completely prevented from flowing into the burner combustion chamber, and the fuel injection nozzle and the spark plug are not contaminated, so that there is no need to flow air from the fuel injection nozzle except during burner combustion.

In addition, the premixed fuel and air are injected from the fuel injection nozzle, and a part thereof adheres to the second DPF to promote combustion, thereby providing a burner with high combustion efficiency. The combustion chamber can be made smaller. Further, since the control of combustion is easy, it can function as a pre-evaporation-mixed lean burner and can be completely burned.

[0014]

【Example】

Embodiment 1 Hereinafter, a DPF burner regeneration device that is Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a DPF burner regeneration device according to the first embodiment. The same components are denoted by the same reference numerals, and redundant description will be omitted.

In FIG. 1, a passage of a casing made of a metal pipe is connected to an exhaust pipe of an internal combustion engine. In this casing, a DPF 1 for purifying exhaust gas is provided.
Are arranged.

A burner combustion chamber 2 for regenerating the DPF 1 is provided upstream of the DPF 1. The burner combustion chamber 2 is provided with a fuel injection nozzle 3 and a spark plug 4. And, this burner combustion chamber 2 and DP
A second DPF 5 is provided at a connection with the passage connected to F1.

Although the internal structure of the DPF 1 and the second DPF 5 is not shown, a large number of gas passage holes extending parallel to the axial direction are formed, and one end of each of the gas passage holes is provided at one of a supply side and a discharge side. Are alternately sealed by small pieces of silicon carbide.

As shown in FIG. 1, when the exhaust gas of the internal combustion engine is introduced into the DPF 1 from the exhaust gas inlet 6, the particulates in the exhaust gas are collected by the wall of the gas passage hole. Then, the purified exhaust gas is discharged from the exhaust gas outlet 7. The particulate concentration can completely prevent the particulates from flowing into the burner combustion chamber 2 by the second DPF 5, and can prevent the particulates from adhering to the fuel injection nozzle 3 and the ignition plug 4.

When the regeneration process of the DPF 1 is performed, the DP
With a predetermined amount of particulates collected in F1, fuel and air mixed in advance are injected from the fuel injection nozzle 3, ignited by the spark plug 4, and the combustion of the particulates in the DPF 1 is started. Part of the injected fuel and air can adhere to the second DPF 5 to promote combustion. Then, the particulates in the DPF 1 are completely burned, and the DPF 1 is regenerated.

Here, the structure of the DPF burner regeneration device of the present invention will be described in detail. As the DPF 1, a porous silicon carbide sintered body having a diameter of 140 mm and a length of 150 mm was used. The fuel injection nozzle 3 used was for high pressure injection of 0.5φ. A glow discharge or glow plug type ignition plug was used. Second DPF5
Is made of a porous silicon carbide sintered body, diameter 50 mm, length 50
mm. Further, the mixing ratio of fuel and air from the fuel injection nozzle was A / F = 20 to 30, and the supply amount was 200 L / min.

In this embodiment, the particulates in the exhaust gas of the internal combustion engine are set to 3 per unit volume (L) of the DPF 1.
0 g was collected and subjected to the above-mentioned regeneration treatment. When this regeneration process was repeated 20 times, no contamination of the fuel injection nozzle 3 and the ignition plug 4 due to particulates was observed.

[0022]

The DPF burner regenerating apparatus of the present invention has the above-mentioned configuration, and the second DPF completely prevents the particulates from flowing into the burner combustion chamber, and the fuel injection nozzle and the ignition plug have the particulates. Therefore, no expensive high-sealing heat-resistant valve and no compressor that supplies a large amount of air at the same time as starting the internal combustion engine are unnecessary, and in the regeneration process, the second DPF is used in the DPF. Complete combustion of particulates can be promoted.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a DPF burner regeneration device according to a first embodiment.

FIG. 2 is a schematic diagram of a conventional DPF burner regeneration device.

FIG. 3 is a schematic diagram of a conventional DPF burner regeneration device.

[Explanation of symbols]

 Reference Signs List 1 DPF 2 Burner combustion chamber 3 Fuel injection nozzle 4 Spark plug 5 Second DPF 6 Exhaust gas inlet 7 Exhaust gas outlet

Continuation of the front page (56) References JP-A-58-20918 (JP, A) JP-A-58-1713 (JP, U) JP-A-59-192613 (JP, U) JP-A-61-25521 (JP) , U) Japanese Utility Model 1986-128323 (JP, U) Japanese Utility Model 2-12017 (JP, U) Japanese Utility Model Application 6-43214 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB) (Name) F01N 3/02

Claims (1)

(57) [Claims] 1. A burner combustion chamber having a fuel injection nozzle and a spark plug upstream of a DPF, wherein the burner regenerates a DPF disposed in a passage connected to an exhaust side of the internal combustion engine by a burner. And a second DPF is disposed at a connection between the passage connected to the DPF and the burner combustion chamber.