JPH09287434A - Filter reclaiming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for reclaiming a filter for collecting particulates in an exhaust gas, wherein the collected particulates the amount of which widely ranges are securely reclaimed so that harmful articles caused by the reclaiming is prevented from being exhausted. SOLUTION: A control means 34 controls the oxygen concentration of gas to be burned by controlling a heating means 9, a gas supplying means 15, an oxygen supplementing means 21, a cleaning means-heating means 2, and an ambient air inducing amount-limiting means 24 based on signals detected by a microwave intencity detecting means 14, a before-filter-gas containing oxygen concentration detecting means 25, an after-filter-gas containing oxygen concentration detecting means 26, an ambient temperature detecting means 27, and an ambient pressure detecting means 28. Thereby, the particulates are efficiently burned out without overheating the filter 4, allowing cleaning means 20 to function efficiently, so that the generation of not burned harmful articles during burning processing may be prevented from being exhausted in the ambient air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention collects particulates (particulate matter) contained in exhaust gas discharged from a diesel engine or the like by a filter and removes the particulates collected by the filter by heating and burning. However, the present invention relates to a filter regenerating device that regenerates the collection performance of the filter.

[0002]

2. Description of the Related Art Generally, in this type of filter regenerator, when the amount of particulates collected by the filter is small, combustion propagation is insufficient and filter regeneration is liable to be insufficient. On the other hand, when the amount of collected particulates is large, cracks are likely to occur due to a large temperature gradient in the filter during filter regeneration, and filter melting damage due to excessive temperature rise of the combustion temperature is likely to occur. Further, the particulate combustion exhaust gas after passing through the filter contains unburned components such as carbon monoxide.

In Japanese Utility Model Publication No. 63-8808, the filter temperature is measured at multiple points, the temperature of the entire filter is accurately grasped, and combustion misfire or combustion temperature overheating is prevented.

Further, JP-A-4-183917 discloses that carbon monoxide in particulate combustion exhaust gas after passing through a filter is converted into harmless carbon dioxide by an oxidation catalyst.

Further, Japanese Patent Laid-Open No. 6-323130 detects the oxygen concentration of the combustion exhaust gas after passing through the filter, and according to the detected oxygen concentration, the recirculation amount of the post-combustion gas to the electric air pump and the secondary air intake amount. Is switched by a valve to supply a gas having a low oxygen concentration for maintaining combustion to the filter to re-combust unburned components generated at the time of regeneration to prevent their discharge and at the same time prevent excessive temperature rise of the filter.

[0006]

However, in the conventional filter regenerating apparatus, when the signal of the temperature detecting means provided in the filter becomes high in temperature, the flow rate of the combustion gas is reduced to suppress the combustion heat generation amount. However, there is a problem that the regeneration time is extended because the oxygen supply amount is reduced.

Further, the oxygen concentration of the post-combustion gas is detected, the electric air pump and the valve are controlled to completely recirculate the post-combustion gas without introducing the atmosphere, and supply the post-combustion gas to the filter. In the case of performing the operation of supplying only the atmosphere (secondary air) without completely recirculating the air, there is a possibility that the combustion temperature may excessively rise when the atmosphere is supplied as the combustion gas.

Further, as the amount of collected particulates increases and the temperature of particulate combustion rises, the oxygen consumption rate due to combustion of particulates increases exponentially, and the oxygen concentration in the combustion exhaust gas decreases. On the other hand, the concentration of carbon monoxide increases with incomplete combustion. Therefore, there is a problem that as the amount of trapped particulates increases, the purification of carbon monoxide by the oxidation catalyst becomes difficult due to lack of oxygen.

[0009]

In order to solve the above problems, the present invention provides a means for mixing a part of a gas after particulate combustion, which is a gas after passing through a filter, with the atmosphere to a gas supply means. It is provided in the reflux path, and the gas supply means supplies the mixed gas to the filter. A means for detecting the oxygen concentration of the gas supplied to the filter is provided, the oxygen concentration of the mixed gas is detected, and the atmospheric mixture amount is controlled based on the detected oxygen concentration.

According to the above invention, the oxygen concentration of the gas supplied to the filter for burning the particulates can be accurately controlled to a desired value (oxygen concentration of about 5 vol%) without being affected by disturbance. As a result, the amount of cooling by the supply gas is close to the amount of heat generated by combustion, and the combustion temperature does not rise excessively even when the amount of oxygen supply is increased, as compared with the case where only the atmosphere is supplied. Therefore, a large amount of particulates can be burnt out in a short time without excessively raising the combustion temperature.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A filter regenerating apparatus according to claim 1 of the present invention comprises a filter for collecting particulates contained in exhaust gas of an internal combustion engine, and heating for heating the particulates collected by the filter. Means, a gas supply means for supplying a gas containing oxygen to the filter, a post-filter gas oxygen concentration detection means for detecting the oxygen concentration of the gas after passing through the filter, and a post-filter gas oxygen concentration Control means for controlling the operation of at least one of the heating means and the gas supply means based on the oxygen concentration detected by the detection means.

After the particulate matter collected by the filter is heated to about 600 ° C., the gas (atmosphere) containing oxygen for promoting the combustion of the particulate matter is supplied to the filter by the operation of the gas supply means, and the particulate matter is discharged. Burn the curate. When the particulate collection amount is small (5
In particulate combustion (g / L or less),
Since the combustion temperature is low, the oxygen consumption rate is low, the supplied oxygen tends to be excessive, and the combustion heat value is small. Therefore, if the air ratio at the time of combustion becomes too large, the heat balance will be predominantly cooled by the supply gas, the combustion temperature will decrease, and misfire will occur. In order to prevent this, a gas oxygen concentration detecting means after passing through the filter is provided to detect the oxygen concentration of the combustion exhaust gas after passing through the filter, and when the air ratio corresponding to the detected oxygen concentration exceeds the upper limit predetermined value. The control means suppresses the gas supply amount, reduces the air ratio, and reduces the cooling amount by the supply gas. Further, the oxygen consumption rate is increased and the combustion heat is increased, so that the heating amount of the heating means is increased. By this control, stable regeneration with little particulate unburned residue is possible even with a low trapping amount, and it is possible to prevent clogging of the filter during long-term use.

The filter regeneration device according to claim 2 is
A filter for collecting particulates contained in the exhaust gas of the internal combustion engine, a heating means for heating the particulates collected by the filter, a gas supply means for supplying a gas containing oxygen to the filter, and the filter A gas discharge path through which the gas after passing through flows, and a purifying means for purifying unburned components contained in the gas after passing through the filter,
An oxygen replenishing unit provided in the gas discharge path and replenishing the gas that has passed through the filter with a gas containing oxygen is provided.

As the trapped amount increases, the combustion temperature rises, the oxygen consumption rate increases exponentially, and the oxygen in the combustion exhaust gas after passing through the filter decreases. This means a reduction in air ratio. On the other hand, the concentration of carbon monoxide generated by incomplete combustion increases as the amount of trapped carbon increases. Oxygen is added to the combustion exhaust gas flowing between the filter and the oxidation catalyst (purification means) that purifies harmful unburned components such as carbon monoxide contained in the combustion exhaust gas after passing through the filter. By inflowing a gas (atmosphere) containing a gas, it is possible to prevent a shortage of oxygen used for purification even if the trapped amount is large, effectively operate the oxidation catalyst, and prevent the discharge of unburned substances.

Further, in the filter regenerating apparatus according to the third aspect, the purifying means heating means is added in the purifying means or in the vicinity of the purifying means in the gas discharge path.

By providing the purifying means heating means in the purifying means or in the vicinity of the purifying means in the gas discharge path, the purifying means can be raised to the activation temperature and the purifying performance can be maximized.

The filter regeneration device according to claim 4 is
A filter for collecting particulates contained in the exhaust gas of the internal combustion engine, a heating means for heating the particulates collected by the filter, a gas supply means for supplying a gas containing oxygen to the filter, and the filter A gas recirculation path that recirculates the gas that has flowed to the gas supply means, and an atmosphere introduction amount regulating means that is provided in the gas recirculation path,
An atmospheric temperature detecting means for detecting the temperature of the atmospheric air and a control means for controlling the operation of the atmospheric introduced amount regulating means based on the temperature detected by the atmospheric temperature detecting means are provided.

Further, in the filter regenerating apparatus according to claim 5, a filter for collecting particulates contained in the exhaust gas of the internal combustion engine, a heating means for heating the particulates collected by the filter, and the filter are provided. A gas supply means for supplying a gas containing oxygen, a gas recirculation path for recirculating the gas that has passed through the filter to the gas supply means, an atmosphere introduction amount regulating means provided in the gas recirculation path, and an atmospheric pressure. It is provided with atmospheric pressure detecting means for detecting, and control means for controlling the operation of the atmospheric introduction amount regulating means based on the pressure detected by the atmospheric pressure detecting means.

In general, the combustion temperature rises as the amount of trapping increases in filter regeneration. In order to prevent melting damage and cracks of the filter due to high temperature, the upper limit of the amount of collected traps is specified. The suppression of the oxygen concentration of the gas supplied to the filter is effective for suppressing the combustion temperature and expanding the amount of recyclable traps. In the filter regenerating apparatus according to claims 4 and 5, the gas supplied to the filter is part of the gas after burning the particulates flowing through the gas recirculation path and the amount introduced by the atmosphere introduction amount defining means. As a mixed gas with the atmosphere, the oxygen concentration of the supplied gas is controlled. Here, at a high trapping amount of about 10 g / L or more and when the supply gas flow rate is several tens of liters per minute, the oxygen concentration in the combustion exhaust gas after passing through the filter is almost zero. Therefore, with a high collection amount,
The oxygen concentration of the supply gas is determined by the ratio of the amount of introduced air to the amount of supply gas (ratio of mass flow rate). The filter regenerating apparatus according to claims 4 and 5 is provided with an atmospheric temperature detecting means or an atmospheric pressure detecting means for detecting the temperature or pressure of the atmosphere, and detects the atmospheric temperature so as to keep the mass flow rate ratio, that is, the oxygen concentration of the supply gas constant. Alternatively, the air introduction amount regulating means is controlled based on the detected pressure to correct the ratio (volume ratio) of the air introduction amount to the gas supply amount. As a result, it is possible to perform stable filter regeneration without the risk of combustion misfire or excessive combustion temperature rise even under special use environments such as cold regions and highlands.

A filter regeneration device according to claim 6 is
A filter that collects particulates contained in the exhaust gas of the internal combustion engine, a gas supply unit that supplies a gas containing oxygen to the filter, and a gas recirculation unit that recirculates the gas that has passed through the filter to the gas supply unit. A path, an air introduction amount regulating means provided in the gas recirculation path, a microwave supplying means for supplying a microwave to the filter, and a microwave intensity detecting means for detecting a microwave intensity of a space containing the filter. And a control unit for controlling the operation of the atmosphere introduction amount defining unit based on the detection intensity of the microwave intensity detecting unit, wherein the control unit detects the detection intensity of the microwave intensity detecting unit during the operation of the gas supply unit. After reaching the minimum value, the ratio of the amount of air introduced to the amount of gas supplied is gradually reduced.

Although particulate combustion progresses in the flow direction of the supply gas in the filter, uneven combustion occurs due to uneven heating of the filter and uneven flow velocity in a cross section perpendicular to the flow direction. When the combustion propagates in the flow direction and the combustion is partially completed up to the filter end surface, oxygen is not consumed in that region, the combustion exhaust gas oxygen concentration rises, and the ratio of the amount of air introduced is constant, The oxygen concentration of the supply gas rises, and the temperature of the combustion region rises. By the way, when the microwave is supplied to the space including the filter and the microwave intensity of the space is detected at an appropriate position, when the combustion is partially completed up to the end face, the microwave intensity detection value that has decreased until then is detected. Turns up, and the detected value takes a minimum value.
Therefore, when the microwave intensity detection value reaches a minimum value, it is considered that the combustion is partially completed, and after that timing, the increase in the oxygen concentration of the supply gas is suppressed by gradually reducing the ratio of the air introduction amount to the gas supply amount. However, it is possible to prevent the combustion region from becoming hot.

Further, a filter regenerating apparatus according to a seventh aspect of the present invention is a filter regenerator for collecting particulates contained in exhaust gas of an internal combustion engine, gas supply means for supplying a gas containing oxygen to the filter, and the filter passage. A gas recirculation path that recirculates the flowed gas to the gas supply means, an atmosphere introduction amount regulating means provided in the gas recirculation path, a microwave supply means that supplies microwaves to the filter, and the filter are housed. Microwave intensity detecting means for detecting the microwave intensity of the space, and control means for controlling the operation of the atmosphere introduction amount regulating means based on the detected intensity of the microwave intensity detecting means, the control means being gas supply means A gradual decrease in the ratio of the amount of air introduced to the amount of gas supplied based on the time when the detection intensity of the microwave intensity detection means during operation becomes a minimum value. And it is controlled.

The degree of progress of combustion differs depending on the collected amount, and the larger the collected amount, the longer the time until partial combustion is completed. Further, the larger the trapped amount, the larger the amount of residual particulates at the time when the combustion is partially completed, so the rate of increase in the oxygen concentration of the combustion exhaust gas after that time point becomes smaller. As described above, the timing of the partial combustion completion and the minimum timing of the microwave intensity detection value coincide with each other, so that the residual particulate amount at the time when the partial combustion ends partially can be estimated. Therefore, the later the detection value of the microwave intensity detection means takes the minimum value,
It is considered that the amount of residual particulates is large at the time when the combustion is partially completed and the ratio of the amount of introduced air to the amount of gas supply is made small, so that the desired supply is achieved until the end of combustion regardless of the trapped amount. The gaseous oxygen concentration can be maintained, and combustion misfire or combustion temperature overheating can be prevented.

A filter regeneration device according to claim 8 is
A filter for collecting particulates contained in the exhaust gas of the internal combustion engine, a heating means for heating the particulates collected by the filter, a gas supply means for supplying a gas containing oxygen to the filter, and the gas A gas supply path for supplying the gas supplied by the supply means to the filter, a gas recirculation path for recirculating the gas that has passed through the filter to the gas supply means, and an atmosphere introduction amount regulating means provided in the gas recirculation path. A pre-filter flow gas oxygen concentration detection unit that is provided in the gas supply path between the filter and the air introduction amount regulating unit and detects the oxygen concentration of the gas before the filter flow; And a control means for controlling the operation of the atmosphere introduction amount regulating means based on the detected oxygen concentration of the gaseous oxygen concentration detecting means.

The oxygen concentration of the gas supplied to the filter after introduction into the atmosphere is detected by the oxygen concentration detecting means, and the amount of introduction into the atmosphere is feedback-controlled so that the detected concentration reaches a desired value. The oxygen concentration fluctuation due to disturbance can be eliminated by further increasing it.

By using the above invention alone or in combination, it is possible to guarantee safe filter regeneration in a wide collection amount and prevention of emission of harmful substances by regeneration.

An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the exhaust gas discharged from the diesel engine 1 is guided to the filter 4 housed in the heating space 3 through the exhaust gas introduction pipe 2. The filter 4 has a honeycomb structure, and collects particulates contained in the exhaust gas when the exhaust gas passes through. The heating space 3 defines a space for substantially confining microwaves by microwave shielding means 5 and 6 having a punching hole configuration or a honeycomb configuration. Reference numeral 7 is a filter holding means provided between the outer periphery of the filter 4 and the tube wall 8 forming the heating space 3, and holds the filter 4 and the filter 4
Suppresses heat transfer from the side of the. This filter holding means 7
The exhaust gas is blocked from passing through the space in which is arranged.

Reference numeral 9 denotes a heating means for heating the particulates collected by the filter 4, which is constituted by a microwave supplying means, and this heating means is hereinafter referred to as a microwave supplying means. The microwave generated by the microwave supply means 9 passes through the rectangular waveguide 10 and the power supply holes 11 and 12 and the heating space 3
To the particulates collected by the filter 4 and dielectrically heated. Reference numeral 13 is a drive power source for the microwave supply means 9. Reference numeral 14 denotes a microwave intensity detecting means for detecting the microwave intensity existing inside or outside the filter holding means 7 by the operation of the microwave supplying means 9.
It has a coaxial line structure. The microwave electromagnetic field state inside the filter 4 changes depending on the amount of particulates collected by the filter 4. The microwave intensity detection means 14 is provided by selecting a position where the detected value of the microwave intensity decreases as the amount of collection increases in a desired collection amount range. Here, the central conductor 15 of the coaxial line is arranged inside or outside the filter holding means 7.

The gas supply means 16 (composed of a compressor, a fan, etc.) supplies a gas containing oxygen to the filter 4 through the gas supply path 17 and promotes particulate combustion. Further, the gas supply means 16 is provided with a check valve (not shown) to prevent the exhaust gas from flowing into the diesel engine 1 during particulate collection. The post-combustion gas after passing through the filter 4 is discharged through the gas recirculation path 18a, the gas discharge path 19, and the purifying means 20. In the present invention, the purifying means 20
Is an oxidation catalyst that oxidizes unburned substances (carbon monoxide, hydrocarbons, etc.) in exhaust gas generated by particulate combustion and renders them harmless. Hereinafter, this purification means is referred to as an oxidation catalyst. In order to make the oxidation catalyst 20 function even when oxygen does not remain in the combustion exhaust gas, the oxygen supplementing means 21
A gas containing oxygen (which may be atmospheric air) is replenished by a (pump or the like), and in order to keep the oxidation catalyst 20 at an active temperature, a purifying means heating means 22 (composed of an electric heater) is provided.

A part of the gas after passing through the filter 4 is also introduced into the atmosphere introduction path 23 through the gas recirculation path 18b together with the atmosphere introduced according to the opening degree of the atmosphere introduction amount regulating means 24 (hereinafter referred to as a valve). It is returned to the gas supply means 16.
The supply gas flow rate (volume ratio) with respect to the amount of introduced air can be controlled only by the opening degree of the valve 24 independently of the supply gas flow rate of the gas supply means 16. Although the gas after passing through the filter 4 has a high temperature due to particulate combustion, the gas recirculation paths 18a and 18b
Acts as a heat exchanger to cool the hot gas. A gas oxygen concentration detecting means 25 after passing through the filter is provided in the middle of the gas circulation path 18a to detect the oxygen concentration of the particulate combustion exhaust gas. In addition, a gas oxygen concentration detecting means 26 before the gas is passed through the gas supply path 17 between the filter 4 and the valve 24.
Is provided to detect the oxygen concentration of the gas that burns the particulates. Further, the atmospheric temperature detecting means 27 and the atmospheric pressure detecting means 28 detect the temperature and pressure of the atmosphere, respectively.

When the filter 4 is regenerated, the valve 29 and the valve 30 are switched so that the exhaust gas of the diesel engine 1 is exhausted.
1, discharged through the muffler 32 and bypassed from the filter 4. The valve 33 is opened when the filter 4 is regenerated, the gas supply means 16 is driven, and the gas after passing through the filter 4 flows into the gas recirculation path 18a.

Reference numeral 34 is a control means for controlling the operations of the microwave supply means 9, the gas supply means 16, the oxygen replenishing means 21, the purification means heating means 22, the valve 24, the valve 29, the valve 30 and the valve 33. The detection signals of the intensity detecting means 14, the post-filtering gas oxygen concentration detecting means 25, the pre-filtering gas oxygen concentration detecting means 26, the atmospheric temperature detecting means 27 and the atmospheric pressure detecting means 28 are inputted. Further, the control means 34 determines the particulate weight collected by the filter 4 based on the microwave intensity detected by the microwave intensity detecting means 14.

The operation of the above configuration will be described below. First, when collecting particulates, the valve 24 and the valve 33 are closed and the valve 2
9, the valve 30 is switched to a predetermined position (the position shown by the broken line in FIG. 1), and the exhaust gas discharged from the diesel engine 1 is passed through the filter 4 to collect the particulates contained in the exhaust gas and to collect the exhaust gas. Purify. When the amount of particulates collected in the filter 4 increases, the pressure loss in the filter 4 increases, the load of the diesel engine 1 increases, and in the worst case, it stops. Therefore, it is necessary to remove (filter regeneration) the particulates collected by the filter 4 under an appropriate collection amount. The microwave supply means 9 is operated periodically, and the control means 34 calculates the collection amount based on the microwave intensity detected by the microwave intensity detection means 14 at that time, and reaches the collection amount that requires regeneration. When the control means 34 judges that it has done so, the control means 34 causes the microwave supply means 9, the gas supply means 16, the oxygen replenishment means 21, the purification means heating means 22, the valve 24, and the valve 2.
9, the valve 30 and the valve 33 are controlled to regenerate the filter 4.

When the filter 4 is regenerated, the valves 29 and 30 are switched to predetermined positions (solid line positions shown in FIG. 1), and exhaust gas is bypassed through the exhaust branch pipe 31 while the diesel engine 1 is operating. Further, the valve 33 is opened and the gas supply means 16
The gas to be supplied can be distributed. The microwave supply means 9 is operated to dielectrically heat the particulates collected by the filter 4 by the microwaves generated thereby. Further, the purifying means heating means 22 is operated to heat the oxidation catalyst 20 to the activation temperature.

The combustion starting temperature of particulates is 6
After heating for about a predetermined time to around 00 ° C, the valve 24
Is set to a predetermined opening degree, and at the same time, the gas supply means 16 is operated to supply a gas containing oxygen to the filter 4 to start the combustion of particulates. Further, the oxygen replenishing means 21 is operated to replenish the exhaust gas flowing through the gas discharge path 19 with oxygen required for the catalytic reaction. Part of the gas after combustion after passing through the filter 4 is a gas recirculation path 18a and a gas discharge path 1
9. After the unburned component is purified through the oxidation catalyst 20, it is discharged to the atmosphere, and the remaining gas after combustion is returned to the gas supply means 16 through the gas recirculation path 18b from the atmosphere introduction path 23 together with the atmosphere defined by the opening degree of the valve 24. To be done. When the gas supply means 16 is operated to perform particulate combustion, the control means 34 causes the microwave intensity detection means 14, the gas oxygen concentration detection means 25 after passing through the filter, the gas oxygen concentration detection means 26 before passing through the filter, and the atmospheric temperature. The microwave supply unit 9, the gas supply unit 16, and the valve 24 are controlled based on the detection signals of the detection unit 27 and the atmospheric pressure detection unit 28.

After the particulate combustion is completed, the operation of the microwave supplying means 9 is stopped and the gas supplying means 1
6 is further operated for a predetermined time to cool the filter 4, and the regeneration of the filter 4 is completed. After that, the gas supply means 16,
The operations of the oxygen replenishing means 21 and the purifying means heating means 22 are stopped, the valves 24 and 33 are closed, the valves 29 and 30 are switched again (the position indicated by the broken line in FIG. 1), and exhausted to the filter 4 just regenerated. Make the gas flowable.

The purpose of the present invention is to safely regenerate a wide collection amount collected by the filter 4 and to prevent discharge of unburned components by regeneration, which will be described in detail below.

In the first invention, in FIG. 1, the control means 34 controls the operations of the microwave supply means 9 and the gas supply means 16 based on the oxygen concentration detected by the gas oxygen concentration detection means 25 after passing through the filter. That is the point. When the trapped amount is small, the combustion temperature is low, so the oxygen consumption rate is low, the supplied oxygen tends to be excessive, and the air ratio during combustion is 1
That is all. Since the calorific value of combustion is originally small, if the air ratio is too large, the heat balance becomes better in cooling, the combustion temperature is lowered, and there is a risk of misfire. Therefore, after the gas has passed through the filter, the oxygen concentration of the combustion exhaust gas is detected by the gas oxygen concentration detection means 25, and when the air ratio corresponding thereto exceeds a predetermined value, the gas supply amount of the gas supply means 16 is suppressed to increase the air ratio. And the amount of cooling by the supply gas is reduced. Further, in order to increase the oxygen consumption rate and increase the combustion heat, the microwave supply amount of the microwave supply means 9 is increased. By this control, stable regeneration with little particulate unburned residue is possible even at a low trapping amount of about 5 g / L or less, and it is possible to prevent clogging of the filter during long-term use.

The second aspect of the present invention is that in FIG. 1, the oxygen replenishing means 21 replenishes the combustion exhaust gas after passing through the filter 4 with a gas containing oxygen (atmosphere). As the trapped amount increases, the combustion temperature increases, the oxygen consumption rate increases exponentially, and the oxygen in the combustion exhaust gas after passing through the filter decreases. This means a reduction in air ratio. On the other hand, the concentration of carbon monoxide generated by incomplete combustion increases as the amount of trapped carbon increases. 10 g / L by supplementing oxygen
Even in the case of regeneration with a high trapping amount above a certain level, the shortage of oxygen used for purification can be prevented, the oxidation catalyst can effectively function, and the emission of unburned substances can be prevented.

The third aspect of the present invention is shown in FIG.
The point is that a purifying means heating means 22 for heating the is provided. As a result, the oxidation catalyst 20 is heated to the activation temperature and the purification performance can be maximized.

The embodiments of the above three inventions are the filter 4
The gas to be supplied to the filter 4 is described as having a configuration in which a part of the combustion exhaust gas after flowing through the filter 4 is recirculated, but the invention is also applied to a general regeneration method in which the gas supply means 16 supplies only the atmosphere. be able to.

By the way, when the flow rate of supply gas is several tens of liters per minute and a low trapping amount of about 5 g / L, the oxygen concentration of combustion exhaust gas after passing through the filter 4 is about 10 vol% or more,
Basically, the supplied oxygen is in an excessive state, and is hardly affected by the oxygen concentration of the supplied gas. However, as described above, the oxygen consumption rate increases with the increase in the collection amount, and the collection amount is 10 g.
If it exceeds about / L, the supply oxygen is completely consumed, and the oxygen concentration of the supply gas controls the combustion temperature. In the present invention, in order to expand the upper limit of the amount of renewable traps, a part of the gas after passing through the filter 4, which is the particulate combustion exhaust gas, depends on the opening degree of the valve 24 provided in the atmosphere introduction path 23 through the gas recirculation path 18b. The gas is recirculated to the gas supply means 16 together with the introduced atmosphere. Here, when the trapping amount is high, oxygen does not exist in the combustion exhaust gas, and the ratio of the amount of introduced air to the supply gas flow rate (volume ratio) is almost independent of the supply gas flow rate of the gas supply means 16 only by the opening degree of the valve 24. Since it is possible to control the flow rate, the valve 2 can be
The oxygen concentration can be controlled with an opening of 4.

The fourth and fifth inventions are atmospheric temperature detecting means 2
8. The atmospheric pressure detection means 29 is provided, and the control means 34 controls the valve 24 based on the detected atmospheric temperature or the detected atmospheric pressure or both, and the ratio (volume ratio) of the atmospheric introduction amount to the gas supply amount is adjusted. This is the point where correction is made as shown in FIGS. Although the density of the introduced air fluctuates due to fluctuations in the temperature and / or pressure of the atmosphere, the mass ratio of the introduced quantity of air to the gas supply quantity, that is, the oxygen concentration of the supplied gas can be kept constant by correction. As a result, it is possible to perform stable filter regeneration without the risk of combustion misfire or combustion temperature overheating even under special use environments such as cold regions and highlands.

As shown in FIG. 4, in the sixth aspect of the invention, after the time (t _L ) when the microwave intensity detected by the microwave intensity detecting means 14 during the operation of the gas supplying means 16 takes the minimum value, the valve 2
4 is that the opening degree is controlled and the ratio of the amount of air introduced to the amount of gas supplied is gradually reduced by the gradually decreasing amount V. Although particulate combustion proceeds in the flow direction of the supply gas in the filter 4, uneven combustion occurs due to uneven heating of the filter 4 and uneven flow velocity in a cross section perpendicular to the flow direction. When the combustion propagates in the flow direction and the combustion is partially completed up to the end surface of the filter 4, oxygen is not consumed in that region, the oxygen concentration in the combustion exhaust gas rises, and the ratio of the amount of air introduced is constant. The oxygen concentration of the supply gas rises, and the temperature of the combustion region rises. By the way, in the configuration in which the microwave is supplied to the space including the filter 4 and the microwave intensity of the space is detected at an appropriate position, when the combustion is partially completed up to the end face, the microwave intensity detection value that has been decreased until then. Turns to rise and the detected value takes a minimum value. Therefore, when the detected microwave intensity reaches a minimum value, it is considered that combustion is partially completed, and after that timing, the ratio of the amount of introduced air to the amount of gas supplied is gradually reduced to suppress an increase in the oxygen concentration of the supplied gas. However, it is possible to prevent the combustion region from becoming hot.

As shown in FIG. 5, the seventh aspect of the invention relates to the gas supply amount based on the time t _L when the microwave intensity detected by the microwave intensity detecting means 14 during the operation of the gas supplying means 16 takes the minimum value. This is a point to control the gradually decreasing amount V of the ratio of the amount of air introduced. The degree of progress of combustion differs depending on the collected amount, and the larger the collected amount, the longer the time until partial combustion is completed. Further, the larger the trapped amount, the larger the amount of residual particulates at the time when the combustion is partially completed, so the rate of increase in the oxygen concentration of the combustion exhaust gas after that time point becomes smaller. As described above, the timing of the partial combustion completion and the minimum timing of the microwave intensity detection value coincide with each other, so that the residual particulate amount at the time when the partial combustion ends partially can be estimated. Therefore, the later the detection value of the microwave intensity detection means takes the minimum value,
It is considered that the amount of residual particulates is large at the time when the combustion is partially completed and the ratio of the amount of introduced air to the amount of gas supply is reduced to a small amount, so that the desired supply until the end of combustion is achieved The gaseous oxygen concentration can be maintained, and combustion misfire or combustion temperature overheating can be prevented.

In FIG. 1, the eighth invention is provided with a pre-passage gas oxygen concentration detecting means 26 for detecting the oxygen concentration of the supply gas, and the opening degree of the valve 24 is adjusted so that the detected oxygen concentration becomes a desired value. This is the point of feedback control. As a result, the accuracy of the oxygen concentration control of the supply gas is further enhanced, the oxygen concentration fluctuation due to disturbance can be excluded, and stable filter regeneration can be guaranteed.

By combining the fourth to eighth inventions with each other, the stability of the control system can be further enhanced.

In this embodiment, the heating means is the microwave supply means 9, but a heating source such as an electric heater or burner may be used.

The bypass backflow regeneration system in which the exhaust gas during regeneration of the filter 4 is bypassed to the exhaust branch pipe 31 and the flow directions of the exhaust gas of the diesel engine 1 and the supply gas of the gas supply means 16 are opposite to the filter 4 will be described. However, the twin filter method in which two filters 4 are provided, the filter 4
On the other hand, the present invention is also applied to a forward flow regeneration system in which the exhaust gas of the diesel engine 1 and the supply gas of the gas supply means 16 have the same flow direction, and a stop regeneration system in which the exhaust branch pipe 31 is eliminated and the filter 4 is regenerated when the diesel engine 1 is stopped. Examples are applicable. In the stopped regeneration method, the timing of performing the regeneration of the filter 4 is limited, and thus the amount of trapped regeneration greatly differs for each regeneration. Since the present invention can safely reproduce a wide collection amount, the degree of freedom in selecting the reproduction timing can be increased in this reproducing method as compared with the conventional case.

[0050]

As described above, according to the filter regeneration apparatus of the present invention, the following effects can be obtained.

(1) After the gas has passed through the filter, a gas oxygen concentration detecting means is provided to detect the oxygen concentration in the exhaust gas after particulate combustion, and the control means supplies the heating amount of the heating means and the gas supply based on the detected value. By controlling at least one of the gas supply amounts of the means, it is possible to perform particulate combustion at a desired air-fuel ratio, and it is particularly effective in preventing combustion misfire when the particulate collection amount is small.

(2) By introducing the atmosphere (oxygen) into the exhaust gas after particulate combustion by the oxygen supplementing means,
Even when the amount of collected particulates is large, oxygen can be secured in the exhaust gas, and the unburned components contained in the exhaust gas can be effectively purified by the purification means (such as an oxidation catalyst).

(3) Purifying means By providing the heating means and heating the purifying means to the activation temperature, the exhaust gas can be effectively purified by the purifying means.

(4) The atmospheric temperature detecting means is provided, and the control means controls the atmospheric introduction amount regulating means based on the detected temperature to correct the ratio of the atmospheric introduction amount to the gas supply amount, so that the temperature of the atmosphere is adjusted. Regardless of this, the oxygen concentration of the supply gas can be kept constant, and stable particulate combustion can be performed even in a special environment such as a cold region.

(5) Atmospheric pressure detection means is provided, and the control means controls the atmospheric introduction amount regulating means based on the detected pressure to correct the ratio of the atmospheric introduction amount to the gas supply amount to obtain the atmospheric pressure. Regardless of this, the oxygen concentration of the supply gas can be kept constant, and stable particulate combustion can be performed even in a special environment such as highlands.

(6) When the detection intensity of the microwave intensity detection means during gas supply reaches the minimum value, the control means considers that the particulate combustion is partially completed, and after that time, controls the atmosphere introduction amount regulating means. By gradually reducing the ratio of the amount of air introduced to the amount of gas supplied, the oxygen concentration of the gas supplied to the filter can be maintained near the desired value until the regeneration is completed, and the temperature rise in the combustion region can be prevented.

(7) It is considered that the longer the time when the detection intensity of the microwave intensity detection means during gas supply by the control means becomes the minimum value, the greater the amount of particulate collection by the filter, and after that time, the amount of air introduced is regulated. By controlling the means to reduce the gradual decrease in the ratio of the amount of air introduced to the amount of gas supplied, the oxygen concentration in the gas supplied to the filter is maintained near the desired value until regeneration is completed regardless of the amount of particulate collection. As a result, optimum particulate combustion can be performed.

(8) By providing a gas oxygen concentration detection means before passing through the filter, and the control means controls the atmosphere introduction amount regulating means based on the detected oxygen concentration, the accuracy of the oxygen concentration control of the supply gas is further enhanced. Further, it is possible to perform more stable particulate combustion.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a filter regeneration device of the present invention.

FIG. 2 is a diagram showing a control method based on the detected atmospheric temperature of the filter regenerator.

FIG. 3 is a diagram showing a control method based on the atmospheric pressure detected by the filter regenerator.

FIG. 4 is a diagram showing a first control method based on the detected microwave intensity of the filter regeneration device.

FIG. 5 is a diagram showing a second control method based on the detected microwave intensity of the filter regeneration device.

[Explanation of symbols]

 4 Filter 9 Heating Means (Microwave Supplying Means) 14 Microwave Intensity Detection Means 16 Gas Supplying Means 17 Gas Supplying Means 18a, 18b Gas Refluxing Means 19 Gas Discharging Means 20 Purifying Means (Oxidation Catalyst) 21 Oxygen Replenishing Means 22 Purifying Means Heating Means 24 Atmosphere introduction amount regulating means (valve) 25 Gas oxygen concentration detecting means after passing through filter 26 Gas oxygen concentration detecting means before passing through filter 27 Atmospheric temperature detecting means 28 Atmospheric pressure detecting means 34 Control means

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Norio Tao 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. A filter for collecting particulates contained in exhaust gas of an internal combustion engine, a heating means for heating the particulates collected by the filter, and a gas supply for supplying a gas containing oxygen to the filter. Means for detecting the oxygen concentration of the gas after passing through the filter, the means for detecting gas oxygen concentration after passing through the filter, and the heating means and the gas based on the oxygen concentration detected by the means for detecting gas oxygen concentration after passing through the filter A filter regeneration device comprising: a control unit that controls the operation of at least one of the supply units. 2. A filter for collecting particulates contained in exhaust gas of an internal combustion engine, a heating means for heating the particulates collected by the filter, and a gas supply for supplying a gas containing oxygen to the filter. Means, a gas discharge passage through which the gas after passing through the filter flows, a purifying means for purifying unburned components contained in the gas after passing through the filter, and a gas discharge passage provided on the gas discharge passage. A filter regenerator comprising: an oxygen replenishing means for replenishing a gas containing oxygen to the gas after flowing. 3. The filter regenerating apparatus according to claim 2, wherein a purifying means heating means is added near the purifying means in the purifying means or in the gas discharge path. 4. A filter for collecting particulates contained in exhaust gas of an internal combustion engine, a heating means for heating the particulates collected by the filter, and a gas supply for supplying a gas containing oxygen to the filter. Means, a gas recirculation path for recirculating the gas that has passed through the filter to the gas supply means, an atmosphere introduction amount regulating means provided in the gas recirculation path, an atmospheric temperature detecting means for detecting the temperature of the atmosphere,
A filter regeneration device comprising: a control unit that controls the operation of the air introduction amount defining unit based on the temperature detected by the air temperature detecting unit. 5. A filter for collecting particulates contained in exhaust gas of an internal combustion engine, a heating means for heating the particulates collected by the filter, and a gas supply for supplying a gas containing oxygen to the filter. Means, a gas recirculation path for recirculating the gas that has passed through the filter to the gas supply means, an atmosphere introduction amount regulating means provided in the gas recirculation path, and an atmospheric pressure detection means for detecting the pressure of the atmosphere,
A filter regeneration device comprising: a control unit that controls the operation of the atmospheric introduction amount defining unit based on the pressure detected by the atmospheric pressure detecting unit. 6. A filter for collecting particulates contained in the exhaust gas of an internal combustion engine, a gas supply means for supplying a gas containing oxygen to the filter, and a gas after the gas has passed through the filter for the gas supply means. A gas recirculation path for recirculating up to, and an atmosphere introduction amount regulating means provided in the gas recirculation path,
Microwave supply means for supplying microwaves to the filter, microwave intensity detection means for detecting the microwave intensity of the space housing the filter, and the amount of atmospheric air introduced based on the detection intensity of the microwave intensity detection means A control means for controlling the operation of the regulating means, wherein the control means has a ratio of the amount of introduced air to the amount of supplied gas after the detection intensity of the microwave intensity detection means during the operation of the gas supply means reaches a minimum value. A filter regeneration device that gradually reduces. 7. A filter for collecting particulates contained in exhaust gas of an internal combustion engine, a gas supply means for supplying a gas containing oxygen to the filter, and a gas supply means for supplying the gas after passing through the filter. A gas recirculation path for recirculating up to, and an atmosphere introduction amount regulating means provided in the gas recirculation path,
Microwave supply means for supplying microwaves to the filter, microwave intensity detection means for detecting the microwave intensity of the space housing the filter, and the amount of atmospheric air introduced based on the detection intensity of the microwave intensity detection means The control means controls the operation of the regulating means, and the control means controls the ratio of the amount of introduced air to the amount of supplied air to the amount of supplied gas based on the time when the detection intensity of the microwave intensity detection means during the operation of the gas supply means has a minimum value. A filter regeneration device that controls a small amount. 8. A filter for collecting particulates contained in exhaust gas of an internal combustion engine, heating means for heating the particulates collected by the filter, and gas supply for supplying a gas containing oxygen to the filter. Means, a gas supply path for supplying the gas supplied by the gas supply means to the filter, a gas recirculation path for recirculating the gas after passing through the filter to the gas supply means, and an atmosphere provided in the gas recirculation path. Introduced amount regulating means, provided in the gas supply path between the filter and the atmospheric introduced amount regulating means, the filter before-passing gas oxygen concentration detecting means for detecting the oxygen concentration of the gas before passing through the filter, A filter regeneration device comprising: a control unit that controls the operation of the air introduction amount regulating unit based on the oxygen concentration detected by the pre-filter flow gas oxygen concentration detecting unit.