JPH11336528A - Black smoke removing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make certain combustion of the black smoke captured by a filter by effectively raising the temp. of the exhaust gas from a diesel engine. SOLUTION: A black smoke removing device is equipped with a filter 13 to capture the black smoke contained in the exhaust gas from a diesel engine 1 and a combustor 11 which can make combustion of the exhaust gas before feeding to the filter, wherein the combustor 11 is furnished with a fuel-air atomizer nozzle 18 capable of feeding a mixture of the fuel and air into the combustor 11 and a glow plug 19 for igniting the mixture gas, and thereby the exhaust gas is combusted by the combustor 11 and the temp. of the gas is raised to a level capable of combusting the black smoke captured by the filter 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for removing black smoke from exhaust gas discharged from a diesel engine, and more particularly, to a diesel engine such as a route bus or a garbage truck that repeatedly travels and stops. It is effective when applied to cars.

[0002]

2. Description of the Related Art In recent years, it has been confirmed that fine particles (DEP) contained in black smoke generated by incomplete combustion of a diesel engine have a bad influence on human health. Various exhaust purifying devices “diesel particulate filter (DPF) devices” (hereinafter referred to as black smoke removing devices) for reducing exhaust particulates have been developed.

FIG. 4 shows a schematic configuration of a conventional black smoke removing apparatus. As shown in FIG. 4, one end of an exhaust passage 111 for discharging the exhaust gas 100 is connected to the diesel engine 110. An injector 1 for injecting fuel 101 such as light oil into the exhaust path 111 is provided near the other end of the exhaust path 111.
16 are attached. At the other end of the exhaust path 111,
Mixer 117 for mixing exhaust gas 100 and fuel 101
Are connected at the entrance side. The outlet side of the mixer 117 is connected to the inlet side of a catalytic combustor 118 using platinum or the like for exhaust gas purification and catalytic combustion. An outlet side of the catalytic combustor 118 is connected to an inlet side of a honeycomb-shaped ceramic filter 119 that captures black smoke from the exhaust gas 100.

[0004] The diesel engine 110 is provided with various sensors (not shown) for detecting a water temperature, a rotation speed, an exhaust temperature, and the like of the engine 110. On the other hand, at the outlet side of the catalytic combustor 118, various sensors (not shown) for detecting a pressure loss, a combustion temperature, and the like of the exhaust gas at the portion are provided. The detection signals of these various sensors are input to the control device 120. The control device 120 controls the driving of the injector 116 according to the input signal.

In such a black smoke removing apparatus, when the exhaust gas 100 discharged from the diesel engine 110 is fed into the filter 119 via the exhaust path 111, the mixer 117, and the catalytic combustor 118, the filter 119 Captures black smoke from the exhaust gas 100, so that the filter 11
Purified gas 103 from which the black smoke has been removed is discharged from the outlet side of No. 9. Further, HC and CO in the exhaust gas are also purified by the catalytic action of the catalytic combustor 12 using platinum or the like.

[0006] As the black smoke in the exhaust gas 100 is captured by the filter 119 in this way, the filter 119 is gradually clogged and the engine output is reduced due to an increase in pressure loss. Therefore, the control device 120 controls the injector 116 based on the detection signals from the various sensors, and when the injector 116 appropriately injects a predetermined amount of the fuel 101 into the exhaust path 111, the fuel 101 and the exhaust gas 100 are mixed in a mixer 117 and burned in a catalytic combustor 118. Thus, when the exhaust gas 100 passes through the filter 119, the exhaust gas 100 heats and burns black smoke captured by the filter 119,
Black smoke is removed from the filter 119 to prevent clogging.

[0007]

However, when the above-described black smoke removing device is applied to a diesel engine vehicle which repeatedly runs and stops frequently, such as a route bus or a garbage truck, when the vehicle stops (when the vehicle is idling) The temperature of the exhaust gas 100 in the engine low load region
Since the ignition temperature of the catalyst combustor 118 does not reach the value of 01, the regeneration work of the filter 119 could be performed only during running (in the middle / high load area of the engine). For this reason, depending on the operating condition of the vehicle, the amount of black smoke to be burned at one time is large, the amount of heat generated in the filter 119 is increased, and the temperature of the filter 119 becomes extremely high, and the filter 119 is damaged. There was a problem such as. Further, since the catalytic combustor 12 using platinum or the like is expensive, there is a problem that the cost of the black smoke removing device is increased.

In view of the above, the present invention provides an inexpensive black smoke removing device capable of effectively raising the exhaust gas temperature of a diesel engine and reliably burning the black smoke captured by the filter. The purpose is to do.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a black smoke removing device according to the present invention comprises a filter for trapping black smoke in exhaust gas from a diesel engine, and a filter for supplying black smoke to the filter. A combustor capable of burning the exhaust gas, the combustor being capable of supplying a mixture of fuel and air into the combustor, and an igniter for igniting the mixture. Wherein the exhaust gas is burned by the combustor and the temperature is raised to a temperature at which the black smoke captured by the filter can be burned.

Further, a sensor for detecting the temperature of the exhaust gas before being introduced into the combustor, a sensor for detecting the temperature of the exhaust gas after being combusted in the combustor, and a sensor for detecting the temperature of the exhaust gas based on detection signals from these sensors. And a control means for controlling the operation of the fuel / air spray nozzle and the igniter.

Further, characterized in that connecting the NO _X purification catalyst on the outlet side of the filter.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a black smoke removing apparatus according to the present invention will be described in detail with reference to the drawings using embodiments.

[First Embodiment] [Configuration] FIG. 1 is a schematic configuration diagram of a black smoke removing device showing a first embodiment of the present invention, and FIG. 2 is a structural explanatory diagram of a pre-combustor.

As shown in FIG. 1, a diesel engine 1
An intake path 3 for sucking fresh air and an exhaust path 4 for discharging exhaust gas are respectively connected to the combustion chamber 2 through valves (not shown), and an injector 5 and a glow as an igniter. A plug 6 is provided. The injector 5 is controlled by the fuel injection control unit 7 to inject pressurized fuel (light oil) from the fuel tank 8 into the combustion chamber 2 at a predetermined injection timing and injection amount, and the glow plug 6 is controlled for starting. When the engine is started, the unit 9 controls the power supply from the battery 10 to generate heat.

The downstream end of the exhaust passage 4 is connected to an inlet of a combustor 11 described later. A honeycomb-shaped ceramic (or non-woven fabric) filter 13 that captures black smoke from exhaust gas is connected to the outlet side of the combustor 11. The combustor 11 and the filter 13 are integrally formed in a cylindrical shape.

At the inlet side of the combustor 11, a fuel / air spray nozzle 18 and a glow plug 19 as an igniter are provided adjacent to the spray nozzle 18. The fuel
The air spray nozzle 18 mixes the pressurized fuel sent from the fuel tank 8 via the flow control valve 15 with the pressurized air sent from the existing compressor 16 via the flow control valve 17. The exhaust gas introduced into the combustor 11 can be sprayed. The glow plug 19
Is heated at a predetermined time from the battery 10 through a relay 20 to generate heat, and the fuel / air spray nozzle 18
It is possible to ignite an air-fuel mixture sprayed from the air.

The flow control valves 15, 17 and the relay 20 are driven and controlled by a signal from a control unit 21 for removing black smoke as control means.
The control unit 21 includes a thermocouple 22a interposed in the exhaust passage 4 to detect an exhaust gas temperature and a combustor 11
A detection signal is input from a thermocouple 22b interposed in the inside and detecting the temperature of the exhaust gas after combustion. Further, the control unit 21 receives detection signals from various sensors (not shown) for detecting the rotational speed of the diesel engine 1 and the like, and detection signals from various sensors (not shown) for detecting the pressure loss of the exhaust gas immediately before the filter 13. Entered as appropriate. In FIG. 1, reference numerals 23a and 23b denote fuel pumps for supplying fuel under pressure.

As shown in FIG. 2, the combustor 11 is formed of a double cylinder composed of an inner cylinder 25 and an outer cylinder 26 whose one end (upstream of the exhaust gas flow) is closed.
Is connected tangentially to the outer cylinder 26 so that exhaust gas is swirled between the inner and outer cylinders 25 and 26 (see arrows in the figure). On the peripheral wall of the inner cylinder 25,
In the same direction as the direction in which the exhaust gas is swirled and introduced between the outer cylinders 25 and 26, nozzle holes 27 for swirling and introducing a part of the exhaust gas are equally formed in the circumferential direction and are multiplexed in the cylinder axis direction. It is formed.

At the center of the end wall of the inner cylinder 25, the fuel
An air spray nozzle 18 is attached, and the above-mentioned glow plug 19 is attached to the inner end of the fuel / air spray nozzle 18 such that the heat generating portion 19a of the fuel / air sprays out from the fuel / air spray nozzle 18 into the inner cylinder 25. It is attached to the upper end wall of the cylinder 25 obliquely downward. The inner wall of the inner cylinder 25 is covered with a ceramic porous body 28 made of a heat-resistant material. Actually, the ceramic porous body 28 is divided into a plurality of pieces in the cylinder axis direction and is assembled so as to be able to absorb thermal deformation.

In the illustrated example, various auxiliary members for improving ignitability and combustion stability are assembled to the combustor 11. That is, in the inner cylinder 25, a cylindrical wire mesh 30 for flame keeping and heat keeping is arranged along the inner peripheral surface of the ceramic porous body 28. A donut-shaped flame holding plate 31 is provided on the inner peripheral surface of the porous ceramic body 28 in the inner cylinder 25, and surrounds the outer edge of the fuel / air spray injected from the fuel / air spray nozzle 18 into the inner cylinder 25. It is attached so that it does. In addition, an appropriate number (four in the figure) of rotation preventing plates 33 are arranged in the circumferential direction in the rear half portion (outlet side of the outer cylinder) between the inner and outer cylinders 25 and 26. In addition, the inner and outer cylinders 25, 2
A fixed or variable aperture ratio flow control plate 34 is provided at the rear end (exit portion of the outer cylinder) between the six.

[Operation / Effect] In such a black smoke removing apparatus, when the exhaust gas discharged from the diesel engine 1 is fed into the filter 13 through the exhaust path 4 and the combustor 11, the filter 13 Captures black smoke from the exhaust gas, so that the exhaust gas from which the black smoke has been removed is discharged from the filter 13.

As described above, the black smoke in the exhaust gas is filtered by the filter 1.
As 3 is captured, the black smoke captured by the filter 13 is accumulated. As the accumulation of black smoke progresses, the pressure loss of the exhaust gas increases, and the engine performance decreases. Therefore, when there is such an abnormal increase in pressure loss, the control unit 21 for black smoke removal detects this by detection signals from various sensors, controls the relay 20 and energizes the glow plug 19, The mixture of fuel and air is sprayed from the fuel / air spray nozzle 18 into the exhaust gas introduced into the combustor 11 under the control of the flow control valves 15 and 17.

Thus, the air-fuel mixture sprayed from the fuel / air spray nozzle 18 is ignited by the glow plug 19,
The exhaust gas from the exhaust path 4 is burned. At this time, the control unit 21 adjusts the temperature of the exhaust gas after combustion based on detection signals from the thermocouple 22a interposed in the exhaust path 4 and the thermocouple 22b interposed in the combustor 11. The operation of the fuel / air spray nozzle 18 and the glow plug 19 is controlled until the temperature at which the black smoke captured by the filter 13 can be burned (about 700 ° or more). That is, the combustion state of the combustor 11 is controlled.

As a result, when the exhaust gas passing through the combustor 11 passes through the filter 13, the black smoke captured by the filter 13 is heated and burned, and
Removes black smoke from garbage and prevents clogging. In other words,
The filter 13 is reproduced.

Therefore, even if the present invention is applied to a diesel vehicle such as a route bus or a garbage truck that repeatedly travels and stops, regardless of the engine operating range (in other words, the exhaust gas temperature), the filter 13 can be used. The black smoke trapped in the engine can be periodically burned and removed, and a decrease in engine performance can be avoided.

In this embodiment, the combustor 11 is formed of a double cylinder, exhaust gas is swirled between the inner and outer cylinders 25 and 26, and the nozzle hole 2 in the peripheral wall of the inner cylinder 25 is formed.
7, the exhaust gas is swirled into the inner cylinder 25, so that the exhaust gas in the inner cylinder 25 can be made uniform and the flow rate can be optimized. Also, the heat generating portion 19a of the glow plug 19
Are mounted so as to straddle the spray outer edge of the fuel / air spray nozzle 18 having the optimum fuel concentration distribution. As a result, the ignitability of the glow plug 19 is improved and the ceramic porous body 2 covering the inner wall of the inner cylinder 25 is improved.
In addition to the fact that the heat retention is enhanced by the method 8, a good combustion state can be obtained even with diesel exhaust gas having a low oxygen concentration, and the temperature of the exhaust gas flowing into the filter 13 can be reliably increased. Further, in the present embodiment, the ignitability and combustion stability of the inner cylinder 25 are further improved by the synergistic effect of the wire netting 30, the flame holding plate 31, the turning prevention plate 33, and the flow rate adjustment plate 34.

In this embodiment, the fuel and the air supplied to the fuel / air spray nozzle 18 are supplied from the existing fuel tank 8 and the compressor 16, so that the cost can be reduced. In addition, in this embodiment, since the catalytic combustor 118 using platinum or the like (see FIG. 4) is not used, the cost of the black smoke removing device can be reduced.

[Second Embodiment] [Configuration] FIG. 3 is a schematic configuration diagram of a black smoke removing apparatus according to a second embodiment of the present invention.

This corresponds to the filter 13 in the first embodiment.
On the outlet side, an example of connecting the inexpensive NO _X purification catalyst 40, such as a selective reduction type and NO _X catalyst. Other configurations are the same as those in FIGS.

[0030] Operation and Effect According to this embodiment, the same operation and effect as the first embodiment in that regeneration of the filter 13 is obtained, in the exhaust gas by inexpensive NO _X purification catalyst 40 There is an advantage that NO _X can be purified.

The present invention is not limited to the above embodiments,
It goes without saying that various changes can be made without departing from the spirit of the present invention. In addition, the present invention is not limited to automobiles, and can be applied to railway vehicles and ships equipped with a diesel engine.

[0032]

According to the first aspect of the present invention, there is provided a filter for trapping black smoke in exhaust gas from a diesel engine,
A combustor capable of burning the exhaust gas before being sent to the filter, the combustor being capable of supplying a mixture of fuel and air into the combustor;
An igniter for igniting the air-fuel mixture, wherein the combustor burns the exhaust gas to raise the temperature to a temperature at which the black smoke captured by the filter can be burned. Therefore, the black smoke captured by the filter can be periodically burned and removed irrespective of the operation area of the engine, and the filter can be effectively regenerated to avoid the deterioration of the engine performance. Also,
Since a catalytic combustor using platinum or the like is not used, the cost of the black smoke removing device can be reduced.

According to the invention of claim 2, a sensor for detecting the temperature of the exhaust gas before being introduced into the combustor, a sensor for detecting the temperature of the exhaust gas after being combusted in the combustor, Since the fuel / air spray nozzle and the control means for controlling the operation of the igniter are provided based on the detection signal from the sensor, the exhaust gas temperature can be efficiently raised.

According to the invention of claim 3, since, characterized in that connecting the NO _X purification catalyst on the outlet side of the filter, NO _X in the exhaust gas by inexpensive NO _X purification catalyst
Can be purified.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a black smoke removing device according to a first embodiment of the present invention.

FIG. 2 is a structural explanatory view of the combustor.

FIG. 3 is a schematic configuration diagram of a black smoke removing device showing a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of an embodiment of a conventional black smoke removing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diesel engine 3 Intake path 4 Exhaust path 8 Fuel tank 10 Battery 11 Combustor 13 Filter 15 Flow control valve 16 Compressor 17 Flow control valve 18 Fuel / air spray nozzle 19 Glow plug 20 Relay 21 Black smoke control unit 22a, 22b Thermocouple 25 Inner tube 26 Outer tube 27 Nozzle hole 28 Porous ceramic body 30 Wire mesh 31 Flame holding plate 33 Rotation preventing plate 34 Flow control plate 40 Catalyst

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[Procedure amendment]

[Submission date] May 7, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

3. A sensor for detecting an exhaust gas temperature before being introduced into the combustor, a sensor for detecting an exhaust gas temperature after being combusted in the combustor, and a sensor for detecting a temperature of the exhaust gas after the combustion in the combustor. 3. The black smoke removing device according to claim 1, further comprising a control unit for controlling the operation of the fuel / air spray nozzle and the igniter.

Wherein black smoke removing apparatus according to claim 1, 2 or 3, wherein the connecting a catalyst for NOx purifying the outlet side of the filter.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a black smoke removing device according to the present invention comprises a filter for trapping black smoke in exhaust gas from a diesel engine, and a filter before sending the filter to the filter. A combustor that can burn the exhaust gas, the combustor has a fuel / air spray nozzle that can supply a mixture of fuel and air into the combustor, and an igniter for igniting the mixture. And ,
Inside the combustor, wire mesh for flame holding, flame holding plate, exhaust gas turning prevention
At least one of the stop plate and the exhaust gas flow control plate
The provided, characterized in that so as to raise the temperature of the temperature by burning the exhaust debris to a temperature capable of combusting the black smoke trapped in the filter by the combustor. In addition, de
A filter that captures black smoke in exhaust gas from diesel engines
Filter and the exhaust gas before being sent to the filter.
A combustor that can be burned, wherein the combustor is
An outer cylinder into which gas is swirled and introduced, and an exhaust gas introduced into the outer cylinder.
Part of the gas is swirled through multiple nozzle holes formed in the peripheral wall.
It is formed by a double cylinder with the inner cylinder that is introduced
Fuel / air injection that can supply a mixture of fuel and air into the inner cylinder
A mist nozzle and an igniter for igniting the mixture
And a guard disposed along the inner surface of the peripheral wall of the inner cylinder.
Wire mesh for flame, the fuel / air spray nozzle in the inner cylinder
Around the outer edge of the fuel / air spray
A flame-holding plate arranged in the circumferential direction on the outlet side of the outer cylinder.
Exhaust gas swirl prevention plate disposed at the outlet of the outer cylinder
At least one of the exhaust gas flow control plates
The exhaust gas is burned by the combustor.
The temperature to combust the black smoke captured by the filter.
The temperature is raised to a certain temperature .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0032

[Correction method] Change

[Correction contents]

[0032]

According to the first and second aspects of the present invention, there is provided a filter for trapping black smoke in exhaust gas from a diesel engine, and a combustor capable of burning the exhaust gas before being sent to the filter. In addition, the combustor includes a fuel / air spray nozzle capable of supplying a mixture of fuel and air into the combustor , and an igniter for igniting the mixture. Wire mesh for flame, flame holding plate, exhaust gas
At least one of the swirl prevention plate and exhaust gas flow adjustment plate
Also provided with one or more, characterized in that the exhaust gas is burned by the combustor and the temperature is raised to a temperature at which the black smoke captured by the filter can be burned ,
It also captures black smoke in exhaust gas from diesel engines.
A filter to be trapped and the exhaust gas before being sent to the filter
A combustor capable of burning gas;
Is an outer cylinder into which the exhaust gas is swirled and introduced and into the outer cylinder.
A number of nozzles formed on the peripheral wall by part of the exhaust gas
When formed with a double cylinder with the inner cylinder swiveled through the hole
In both cases, a fuel that can supply a mixture of fuel and air into the inner cylinder is provided.
Air / air spray nozzle and an inlet for igniting the mixture
And a dispenser along the inner surface of the peripheral wall of the inner cylinder.
A flame holding wire to be installed, and the fuel / air injection into the inner cylinder.
Surrounds the outer edge of fuel / air spray from mist nozzle
A flame holding plate disposed in such a manner as to surround the outlet side of the outer cylinder.
A plurality of exhaust gas swirl prevention plates disposed in
Of the exhaust gas flow control plates provided at the outlet of the cylinder,
At least one of the exhaust gas
And the temperature of the black smoke captured by the filter
The feature is that the temperature is raised to a temperature where it can be burned
Since the, regardless of black smoke that is trapped in the filter to the operating area whether the engine, periodically it is possible to burn and remove, effectively reduced performance of the engine and regenerate the filter can be avoided in advance. Further, since a catalytic combustor using platinum or the like is not used, the cost of the black smoke removing device can be reduced. In addition, a low oxygen concentration
Improved combustor ignitability and stable combustion even with diesel exhaust gas
Is done.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction contents]

According to the invention of claim 3 , a sensor for detecting the temperature of the exhaust gas before being introduced into the combustor, a sensor for detecting the temperature of the exhaust gas after combustion in the combustor, Since the fuel / air spray nozzle and the control means for controlling the operation of the igniter are provided based on the detection signal from the sensor, the exhaust gas temperature can be efficiently raised.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction contents]

According to the fourth aspect of the present invention, since a NOx purifying catalyst is connected to the outlet of the filter, the NOx in the exhaust gas can be reduced by the inexpensive NOx purifying catalyst.
Can be purified.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sadanori Toyama 3000 Tana, Sagamihara-shi, Kanagawa Prefecture Mitsubishi Heavy Industries, Ltd.Sagamihara Works Co., Ltd. Sagamihara Factory

Claims (3)

[Claims] 1. A filter for trapping black smoke in exhaust gas from a diesel engine, and a combustor capable of burning the exhaust gas before being sent to the filter, wherein the combustor includes the combustor. A fuel / air spray nozzle capable of supplying a mixture of fuel and air therein, and an igniter for igniting the mixture, wherein the combustor combusts the exhaust gas and captures its temperature with the filter. A black smoke removing device wherein the temperature of the black smoke is increased to a temperature at which the black smoke can be burned. 2. A sensor for detecting an exhaust gas temperature before being introduced into the combustor, a sensor for detecting an exhaust gas temperature after being combusted in the combustor, and a sensor based on detection signals from these sensors. The black smoke removing device according to claim 1, further comprising a control unit for controlling the operation of the fuel / air spray nozzle and the igniter. Wherein black smoke removing apparatus according to claim 1 or 2, wherein the connecting a NO _X purifying catalyst on the outlet side of the filter.