JPH06200734A - Soot combustor - Google Patents

Abstract

PURPOSE:To make a soot combustor compact and applicable easily to the exhaust pipe of a diesel engine, and allow soot, collected from the exhaust gas of the diesel engine, to be combusted efficiently at the low temperature. CONSTITUTION:A soot combustor includes a heat-transfer housing 12 disposed at the intermediate part of the exhaust pipe 22 of a diesel engine and provided with a combustion gas outlet 13 at one end thereof, innumerable granular oxidizing catalysts 14 filled in the heat-transfer housing 12, and a soot filling nozzle 15 disposed on the other end side of the heat-transfer housing 12 so as to blow soot into the heat-transfer housing 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soot combustor for treating soot that is discharged from a diesel engine along with exhaust gas and collected by the filter.

[0002]

BACKGROUND ART Normally, the soot contained in the exhaust gas of a diesel engine is collected by a particulate trap, collected in a soot pool, and then heated and burned by an electric heater. It was Then, with such a treatment method, the collected soot could not be treated efficiently at a low temperature.

[0003]

An object of the present invention is to enable miniaturization to be easily applied to an exhaust pipe of a diesel engine, and to efficiently burn soot collected from the exhaust gas of the diesel engine at a low temperature. The purpose is to provide a soot combustor that can be processed.

[0004]

[Means corresponding to the problem and its action]
A heat transfer housing having a combustion gas outlet at one end and disposed in the middle of an exhaust pipe of a diesel engine, a myriad of granular oxidation catalysts filled in the heat transfer housing, and the other end of the heat transfer housing And a soot injection nozzle for blowing soot into the heat transfer housing, and heating the soot collected from the exhaust gas of the diesel engine and blown into the heat transfer housing with the exhaust gas. It is a place where low temperature combustion is performed by promoting combustion with an oxidation catalyst.

[0005]

DESCRIPTION OF SPECIFIC EXAMPLES Specific specified examples of the soot combustor of the present invention will be described below with reference to the drawings. 1 and 2 are mounted on a truck (not shown), and
The specific example 10 of the soot combustor of this invention applied to the diesel engine 20 in which the particulate trap device 30 is provided in the exhaust system is shown. The soot combustor 10 was used in particular in a soot combustor 40 associated with the particulate trap device 30. The soot combustor 10 is incorporated in a casing 11 connected midway of an exhaust pipe 22 of the diesel engine 20 between a two-system type backwash particulate trap 31 and an exhaust muffler (not shown), Then, a cylindrical heat transfer housing 12 having a combustion gas outlet 13 at one end, and a myriad of granular oxidation catalysts 14 filled in the heat transfer housing 12
And a soot injection nozzle 15 which is disposed at the other end of the heat transfer housing 12 and allows soot to be blown into the heat transfer housing 12. Of course, the casing 11 is provided with the gas inlet 16 and the gas outlet 17, and the gas inlet 1 is provided in the middle of the exhaust pipe 22.
6 and the gas outlet 17 were flanged.

The heat transfer housing 12 has its combustion gas outlet 13 located downstream and its soot injection nozzle 15 located upstream with respect to the exhaust gas of the diesel engine 20 flowing in the casing 11. Incorporated inside and its casing 11
The countless granular oxidation catalysts 14 can be heated by the exhaust gas flowing inside.

The countless granular oxidation catalysts 14 have a particle size of 0.
Add 0.2 to 5 palladium on 5-5mm alumina pellets
It was produced by supporting a supported amount of ˜5 gr / l. As a result, the soot combustion temperature was lowered from 700 ° C to 450 ° C. In the granular oxidation catalyst 14, the alumina pellets may be spherical or chip-shaped, and platinum or the like may be supported on the alumina pellets instead of the palladium as the active species.

The soot injection nozzle 15 includes a transportation pipe 47.
Is connected to the particulate hopper 34 of the two-system type backwash particulate trap 31, and the soot collected by the particulate hopper 34 and sent by compressed air is blown into the heat transfer housing 12. Of course, in the soot combustor 10, the heating chamber 45 in which the electric heater 46 is incorporated is connected in the middle of the transportation pipe 47, so that the soot can be burned even when the exhaust gas temperature is low such as when the engine is started. .

Further, the soot combustor in which the soot combustor 10 has been used is as follows. The soot combustor 10 and the particulate hopper 34 of the two-system type backwash particulate trap 31 are connected by the pneumatic piping 44. Connected to the air tank 41, an electromagnetic shutoff valve 42 and an electromagnetic flow rate adjusting valve 43 arranged in the middle of the pneumatic pipe 44, and a heating chamber 45 arranged in the middle of the transportation pipe 47. It was Of course, compressed air is supplied to the air tank 41 by a compressor (not shown).

On the other hand, the particulate trap device 30 to which the soot combustion device 40 is attached is a two-system type backwash particulate trap 31 and a pair of particulate traps 31. A pair of electromagnetic exhaust gas cutoff valves (not shown) for connecting the filter chambers 32 and 33 to the exhaust pipe 22 and a pair of pneumatic blowers connecting the pair of particulate filter chambers 32 and 33 to the air tank 41. Inlet pipe (not shown), a pair of electromagnetic air pressure cutoff valves (not shown) arranged in the air pressure blow pipe, and a microcomputer unit (which operates the electromagnetic exhaust gas cutoff valve and the electromagnetic air pressure cutoff valve). (Not shown). Of course, the microcomputer unit operates the electromagnetic shutoff valve 42 and the electromagnetic flow rate adjusting valve 43, which also controls the soot combustion device 40.

Next, the operation of the soot combustor 10 will be described with reference to the traveling of the truck. Now that diesel
When the engine 20 is operated and the truck starts traveling, the exhaust gas of the diesel engine 20 flows through the exhaust manifold 21 to the upstream side of the exhaust pipe 22, and the particulate trap 31, the casing 11, And then, it sequentially flows to an exhaust muffler (not shown) and further flows to a tail pipe (not shown) to be discharged into the atmosphere. And that diesel engine 2
The soot contained in the exhaust gas of 0 starts to be collected by the particulate filter (not shown) when the exhaust gas passes through the pair of particulate filter chambers 32 and 33. At that time, Since the exhaust pressure is low, the microcomputer unit controls the current flowing through the electromagnetic exhaust gas cutoff valve and the electromagnetic air pressure cutoff valve with the signal from the exhaust pressure sensor (not shown), and the electromagnetic exhaust gas cutoff valve opens. The electromagnetic air pressure shutoff valve is closed.

The truck is further driven, soot contained in the exhaust gas is successively collected by the particulate filter, and at the same time, exhaust pressure is applied to the microcomputer unit by the exhaust pressure sensor. Since the microcomputer unit is comparing whether the exhaust pressure exceeds a predetermined value, when the exhaust pressure exceeds the predetermined value, the microcomputer unit causes the pair of electromagnetic waves to be released. The current flowing through one of the exhaust gas cutoff valves and one of the pair of electromagnetic air pressure cutoff valves is controlled, and first, the one electromagnetic exhaust gas cutoff valve is closed and one of the pair of particulate filter chambers 32, 33 is connected to one of the two. The inflowing exhaust gas is shut off, and then one of the electromagnetic pneumatic shutoff valves is opened and closed for a predetermined time. When one of the electromagnetic pneumatic shutoff valves is opened for such a short time, the compressed air passes from one of the pair of pneumatic blowing pipes to the one of the particulate filter chambers 32 of the air tank 41. The soot that has been blown in and collected by the particulate filter is blown away. Of course, the soot blown off from the particulate filter is
Collected in the particulate hopper 34.

Subsequently, the microcomputer unit controls the electric current flowing through the electromagnetic exhaust gas cutoff valves, and in turn, one electromagnetic exhaust gas cutoff valve is opened and the other electromagnetic exhaust gas cutoff valve is closed. Exhaust gas is allowed to pass through one of the particulate filter chambers 32,
The other particulate filter chamber 33
The exhaust gas flowing into is shut off, and then the other electromagnetic pneumatic shutoff valve is opened and closed for a predetermined time. In such a short time, the other electromagnetic air pressure shutoff valve is opened, and compressed air is blown from the air tank 41 into the other particulate filter chamber 33 through the other air pressure blowing pipe to make a particulate.・ Blow off the soot collected by the filter. Then, the microcomputer unit controls the current flowing through the other electromagnetic exhaust gas cutoff valve to open the other electromagnetic exhaust gas cutoff valve,
The exhaust gas is also passed through the other particulate filter chamber, thus completing the first filter regeneration. Of course, in the other particulate filter chamber 33, the soot blown off from the particulate filter is collected in the particulate hopper 34.
Collected in.

Further, when the truck continues to run,
The particulate trap device 30 collects soot contained in the exhaust gas while repeating the filter regeneration described above. Then, the exhaust gas from which the soot has been removed by the two-system type backwash particulate trap 31 flows into the casing 11 and flows into the casing 11,
The soot combustor 10 is heated. And this soot combustor 1
At 0, the countless granular oxidation catalysts 14 filled in the heat transfer housing 12 are heated to the temperature of the exhaust gas.

On the other hand, the soot burning device 40 is connected to the electromagnetic shutoff valve 4 by the microcomputer unit.
2 and the current flowing through the electromagnetic flow rate adjusting valve 43 is controlled,
The electromagnetic flow control valve 43 is throttle-adjusted according to the load of the diesel engine 20, and the electromagnetic shutoff valve 42 is opened and closed for a predetermined short time. While the electromagnetic shut-off valve 42 is opened for a short time, compressed air flows from the air tank 41 to the particulate hopper 34 via the pneumatic pipe 44 and to the particulate hopper via the transportation pipe 47. Soot from the nozzle 34 to the soot injection nozzle 15, and the soot injection nozzle 15 transfers the soot to the heat transfer housing 12
Let it blow in. The blown soot is burned by touching the heated innumerable granular oxidation catalysts 14 and becomes a gas from the combustion gas outlet 13 into the casing 11 where it is mixed with the exhaust gas.
Furthermore, it flows into the exhaust muffler. In this way, the soot was burned on the myriad of particulate oxidation catalysts 14, so that the combustion temperature of the soot was lowered to a low temperature of 400 to 450 ° C., and the soot was burned efficiently. So-called soot can be burnt at low temperatures. Then, while the truck is traveling, the soot burning device 40 repeatedly performs the soot burning process described above. Of course, the soot burning device 4
0 has been described where the soot combustor 10 was incorporated into the exhaust pipe, the soot combustor 10 could be located outside the exhaust pipe 22 and adjacent to the particulate hopper 34. In that case, it is desirable to incorporate an electric heater in the heat transfer housing 12.

FIG. 3 likewise shows another embodiment 50 of the soot combustor of the invention applied to the exhaust system of the diesel engine 20 mounted on the truck.
In the soot combustor 50, a coiled sheath heater 51 and a temperature sensor 52 are added to the soot combustor 10 shown in FIGS. 1 and 2, and the heating chamber 45 is omitted from the soot combustor 10. Embodied in structure. This soot combustor 5
At 0, the sheathed heater 51 is arranged in the heat transfer housing 12, so that the innumerable granular oxidation catalysts 14 filled in the heat transfer housing 12 are uniformly heated and the oxidation catalyst 14 is heated. Temperature distribution became uniform. Of course, the soot combustor 50 was operated similarly to the soot combustor 10.

FIG. 4 similarly shows yet another embodiment 60 of the soot combustor of the present invention applied to the exhaust system of the diesel engine 20 mounted on the truck. The soot combustor 60 includes a heat transfer housing 61, an innumerable granular oxidation catalyst 14 filled in the heat transfer housing 61, a plurality of soot injection nozzles 15, a plurality of coiled sheath heaters 51, and a temperature sensor. It was assembled with 52.

The heat transfer housing 61 has an outer cylinder 62 whose both ends are closed, and an outer cylinder 6 which penetrates both ends of the outer cylinder 62.
2 arranged coaxially with the outer cylinder 62, and an inner cylinder 6 having an annular soot combustion chamber 64 and an exhaust gas passage 65 defined therein.
And one of both ends of the inner cylinder 63 penetrating both ends of the outer cylinder is utilized as the gas inlet 66 and the other end of the inner cylinder 63 is utilized as the gas outlet 67, respectively. Each of the gas inlet 66 and the gas outlet 67 is provided with a flange so that it can be connected to the middle of the exhaust pipe 22 by a flange. Of course, the inner cylinder 63 is disposed inside the outer cylinder 62 on the gas outlet side thereof in the annular soot combustion chamber 6.
4 is connected to the exhaust gas passage 65 of the combustion gas outlet 68
Is formed, and the gas in which the soot is burned in the annular soot combustion chamber 64 flows from the exhaust gas outlet 68 to the exhaust gas passage 65, and is mixed there with the exhaust gas.

The countless granular oxidation catalysts 14 are filled in the annular soot combustion chamber 64 of the heat transfer housing 61, and
The soot injection nozzle 15, the coiled sheath heater 51,
And, the temperature sensor 52 was disposed in the annular soot combustion chamber 64 of the heat transfer housing 61 as shown.

The soot combustor 60 manufactured in such a structure was operated similarly to the soot combustors 10, 50 previously described.

As is apparent from the embodiments of the present invention described above with reference to the drawings, those skilled in the art to which the present invention pertains have ordinary knowledge in the art. In order to achieve the object of the invention, it is easy to obtain a mode that is derived from the technical essence of the invention, which is essential for the formation of the invention and is the nature of the invention, and which is objectively recognized as being inherent. Is embodied in.

[0022]

Benefits of the Invention As can be seen from the above, the soot combustor of the invention has a combustion gas outlet at one end and
A heat transfer housing disposed in the middle of an engine exhaust pipe, an innumerable granular oxidation catalyst filled in the heat transfer housing, and soot placed in the heat transfer housing at the other end side of the heat transfer housing. In the soot combustor of the present invention, the soot collected from the exhaust gas of the diesel engine is heated by the exhaust gas and is promoted to burn by the countless granular oxidation catalyst. It burns efficiently at low temperatures, reduces environmental pollution, and
The miniaturization makes it easy to install in a vehicle, and as a result, it is very useful and practical for a vehicle's diesel engine.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a specific example of a soot combustor of the present invention applied to a diesel engine mounted on a truck and having a particulate trap device and a soot combustion device in an exhaust system. .

2 is a vertical cross-sectional view of the soot combustor shown in FIG.

FIG. 3 is a longitudinal sectional view showing another embodiment of the soot combustor of the present invention applied to the exhaust system of the diesel engine shown in FIG.

FIG. 4 is a longitudinal sectional view showing still another embodiment of the soot combustor of the present invention applied to the exhaust system of the diesel engine shown in FIG.

[Explanation of symbols]

 11 Casing 12 Cylindrical Heat Transfer Housing 14 Granular Oxidation Catalyst 15 Soot Injection Nozzle

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroshi Funabashi 3-1-1 Hinodai, Hino City, Tokyo Hino Motors Co., Ltd. Hino Factory

Claims (1)

[Claims] 1. A heat transfer housing having a combustion gas outlet at one end and arranged in the middle of an exhaust pipe of a diesel engine, a myriad of particulate oxidation catalysts filled in the heat transfer housing, and heat transfer thereof. A soot combustor including a soot injection nozzle which is disposed on the other end side of the housing and blows soot into the heat transfer housing.