JP2924288B2 - Filter regeneration device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter for an internal combustion engine for collecting particulates (particulate matter) contained in exhaust gas discharged from a diesel engine and a filter for collecting particulates, which is used for microwave energy. The present invention relates to an apparatus for reproducing using a.

[0002]

2. Description of the Related Art In recent years, regulations on the emission of air pollutants have been tightened in countries around the world for fixed sources such as cogeneration and mobile sources such as automobiles. In particular, regulations on exhaust gas from automobiles have greatly reduced the regulatory values themselves, which have been shifted from conventional concentration regulations to total quantity regulations.

[0003] Among automobiles, diesel cars are in the process of tightening regulations on emission of particulates as well as nitrogen oxides. It is said that it is impossible to achieve the exhaust gas regulation value only by reduction measures such as fuel injection timing delay by improving the fuel. At present, it is essential to provide a post-treatment device for purifying exhaust gas. As a post-treatment device of a diesel engine, a method of using a filter for collecting particulates mainly composed of black smoke contained in an exhaust gas stream has been studied.

[0004] It is known that particulates burn at about 600 ° C. As a heating means for raising the temperature of the particulates to this temperature, a burner method, an electric heater method, a microwave method, or the like is considered.

FIG. 4 shows a filter regenerating apparatus in which a heating means uses a microwave system (for example, Japanese Patent Laid-Open No. Sho 59-1260).
No. 22). In the figure, 1 is an engine, 2 is an exhaust manifold, 3 is an exhaust pipe, 4 is an exhaust branch pipe, 5 is a filter, 6 is a heating chamber containing the filter, 7 is microwave generating means, 8 is microwave generating means. A waveguide for guiding the generated microwaves to the heating chamber; 9 a microwave reflecting plate;
Reference numeral 0 denotes an air pump, 11 denotes an air supply path, 12 denotes a drive power source for microwave generation means, 13 denotes a muffler, 14 denotes an air switching valve, and 15 denotes an exhaust gas switching valve.

However, if the particulates continue to be collected, the filter causes clogging and greatly reduces the trapping ability, and also worsens the flow of exhaust gas to lower the engine output or stop the engine. Cause such problems.

[0007] Accordingly, although technology development for regenerating the trapping ability of filters is currently being promoted throughout the world, it has not yet been put to practical use.

In the above configuration, the exhaust gas of the engine is guided to the filter 5 by the exhaust gas switching valve 15 or directly discharged to the atmosphere. In the particulate collection process, the exhaust gas is guided to the filter 5 and the particulates contained in the exhaust gas are collected by the filter 5. When the trapping capacity reaches the limit, the exhaust gas switching valve 15 is controlled to shut off the exhaust gas to the exhaust pipe 3, and all the exhaust gas is exhausted to the atmosphere via the exhaust branch pipe 4. During this time, the regeneration of the filter 5 is performed.

In this filter regeneration process, the particulates collected by the filter are heated by the microwave generating means 7 and the air required for combustion is supplied from the air pump 10 to start the combustion. When the regeneration of the filter is completed after a predetermined time, the exhaust gas switching valve 15 is controlled again, the exhaust gas is guided to the filter 5, and the collection is started. This process of collection and regeneration is repeated.

[0010] The filter 5 of the above filter regeneration apparatus is shown in FIG.
As shown in (1), a honeycomb structure having a large number of through holes 16 formed by partition walls made of porous ceramic such as cordierite and mullite is applied. At both ends of the through hole 16 of the honeycomb structure, sealing plugs 17 and 18 having airtightness are provided alternately so that exhaust gas is discharged through a porous ceramic partition wall. It is trapped on the porous ceramic partition wall on the inflow side of the exhaust gas.

[0011]

However, in the filter regeneration process having the above structure, the vicinity of the filter end face on the supply side of the air necessary for combustion is cooled by the supply of the air, so that the temperature rise of the particulates is hindered, and the particulates are prevented from rising. The combustion of the filter became difficult and the combustible region of the particulates was narrowed, so that the entire filter could not be effectively regenerated. As a result, when the air required for combustion is supplied from the side where the exhaust gas flows in the continuous repetition of collection and regeneration of the particulates, the exhaust gas inflow holes are not formed near the end face of the filter due to the accumulation of the non-regenerated particulates. There is a problem that the filter is clogged and the collecting function as a filter is lost, and the collecting performance and the regenerating performance are significantly reduced. On the other hand, when air necessary for combustion is supplied from the side from which exhaust gas flows, the problem is that the filter collection volume decreases due to the residual particulates that are not regenerated near the filter end face, and the collection performance as a filter decreases. there were.

When the particulate combustion moves to the rear of the filter, the vicinity of the end face of the filter is cooled by the dissipation of heat. On the other hand, the temperature inside the filter becomes high due to the particulate combustion and the temperature difference becomes large. However, there was a problem that the trapping performance was reduced and the trapping function was lost.

Further, it takes a lot of time to raise the particulates in the vicinity of the filter end face to a combustible temperature, and it is practical to supply a driving power source for the microwave generation source from a power source mounted on an automobile. Had a difficult task.

The present invention solves the above-mentioned problems, and realizes efficient regeneration of particulates deposited near the end face of a filter, prevents the occurrence of cracks, and continuously improves collection and regeneration performance as a filter. And a filter regeneration device capable of shortening the time required for the particulate matter near the filter end surface to burn to a temperature at which the particulates burn and shortening the time required to drive the microwave generation source from the power source mounted on the vehicle. It is intended for.

[0015]

In order to achieve the above object, a filter regeneration apparatus according to the present invention comprises a heating chamber provided in an exhaust pipe for discharging exhaust gas of an internal combustion engine, and a microwave supplied to the heating chamber. comprising a microwave generating means for generating a filter for collecting particulates contained in the exhaust gas of the internal combustion engine housed in the heating chamber, and an air supply means for supplying air to the heating chamber, wherein The filter is formed of a honeycomb structure having a large number of through holes formed by porous ceramic partitions surrounded by an outer frame, and one end of each of the through holes has the through holes present at intervals of one another in an adjacent direction. A first sealing plug made of a ceramic cement material having airtightness in the hole and a ceramic cement material having airtightness in a through hole not provided with the first sealing plug at the other end of the through hole. Provided with a second sealing plug comprising the honeycomb structure is located inside the end face of the through hole of the honeycomb structure of the first sealing plug side for supplying air by the air supply means And a heat radiation prevention part integral with the air supply part.
The arrangement is such that it is located on the supply means side .

[0016]

The filter regeneration apparatus of the present invention has
When the particulates collected by the filter are heated by the heating means by microwaves, the radiation preventing portion from the end face of the filter provided on the air supply side to the position of the sealing plug is removed from the heated particulates. Since it has a function to prevent heat radiation, it can increase the temperature rise rate,
The particulates can reach the combustible temperature in a short time.

Further, even if the air required for combustion is supplied to the filter after the particulates have been heated to the combustible temperature, the presence of the radiation preventing portion suppresses the cooling of the filter portion by the air. Can be burned almost completely, and its performance can be prevented from being reduced and can be maintained permanently during repeated collection and regeneration.

Further particulate from the supply side of the gas is moved rearward gradually filters the combustion zone begins to combust, but the filter portion completing combustion the heat dissipation
Since the cooling effect is prevented by the heat insulating effect of the prevention unit, the temperature difference from the part heated by the particulate combustion can be reduced, and the occurrence of cracks in the filter due to thermal distortion can be prevented.

[0019] Since the short time it is possible to reach the particulate in the combustible temperature can be practically supplied from a power source mounted to the drive power of the microwave source to the motor vehicle.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 (a) and (b) is a plan view and a cross-sectional view of Fi <br/> filter applied to the filter regeneration system for an internal combustion engine in an embodiment of the present invention. In FIG.
Is a honeycomb structure having a large number of through holes 19a formed by porous ceramic partitions surrounded by an outer frame;
It is composed of ceramic materials such as cordierite and mullite. At one end of the through hole 19a, first sealing plugs 20 made of an airtight ceramic cement material are provided at every other interval in the adjacent direction so as to be located inside the end face of the through hole 19a. And the through hole 19
There is a heat radiation preventing portion 22 having no filter function between the end face of a and the first sealing plug 20. On the other hand, the other end of the through hole 19a does not have the first sealing plug 20.
Is provided with a second sealing plug 21 made of an airtight ceramic cement material.

Exhaust gas flows from one end of the through hole 19a, passes through a porous ceramic partition, and passes through the through hole 1a at the other end.
It is discharged from 9a. The particulates contained in the exhaust gas are collected on the porous ceramic partition walls on the exhaust gas inflow side. In the above-mentioned filter, the flow direction of the exhaust gas may be on the first sealing plug 20 side or on the second sealing plug 21 side.

FIG. 2 shows the configuration of a filter regeneration device for an internal combustion engine according to an embodiment of the present invention.

In FIG. 1, reference numeral 23 denotes an exhaust pipe for exhausting exhaust gas from an internal combustion engine, 24 denotes a heating chamber provided in the middle of the exhaust pipe 23, and 25 denotes a heating chamber which is housed in the heating chamber 24 while the exhaust gas passes therethrough. It is a filter for collecting particulates contained in exhaust gas, and the filter having the configuration shown in FIG. 1 is applied. Reference numeral 26 denotes microwave generating means for generating microwaves for supplying power to the heating chamber 24, 27 denotes cooling means for cooling the microwave generating means 26, and 28 transmits microwaves generated from the microwave generating means 26 to the heating chamber 24. It is a waveguide. 29 is air <br/> supply means for supplying air to the heating chamber 24, the air supply means 29 is applied blower or pump, air passes the heating chamber 2 Shirubefukan 30
It is led to 4. The filter 25 is arranged such that the heat radiation preventing portion 22 is on the air supply side, that is, on the side of the air guide tube 30. A check valve 31 is provided in the middle of the air guide tube 30 to allow air to pass therethrough but to prevent exhaust gas from flowing into the air supply means 29. An exhaust branch pipe 32 controls the flow of exhaust gas to the exhaust branch pipe 32 and the filter 25 by switching a valve 33 provided in the exhaust pipe 23 and a valve 34 provided in the exhaust branch pipe 32. Will be The illustrated positions of the valves 33 and 34 correspond to the case where the exhaust gas flows to the filter 25 side. Reference numerals 35 and 36 denote microwave shielding means for limiting the heating chamber 24, and have a configuration of punching holes or a honeycomb configuration. 37 is the filter 25
Is a heat insulating material provided between the outer periphery of the heating chamber 24 and the inner wall of the heating chamber 24, and also serves to support the filter 25 in the heating chamber 24.

The exhaust gas flows through the exhaust pipe 23 from the direction indicated by the arrow in FIG. The particulates contained in the exhaust gas are collected by the porous ceramic partition on the exhaust gas inflow side by the filter function of the filter 25, and the purified exhaust gas passes through the porous ceramic partition and flows out of the filter 25. Discharged into the atmosphere. At this time, since the heat radiation preventing portion 22 provided on the filter 25 does not have a filter function, the amount of accumulated particulates is smaller than that of the portion having the filter function.
Therefore, when the heat radiation preventing portion 22 exists on the exhaust gas inflow side, the accumulation of the particulates on the heat radiation preventing portion 22 is suppressed, so that the clogging of the through hole 19 is prevented, and the trapping performance as a filter is prevented from lowering. Is done.

On the other hand, if particulates continue to be collected in the filter 25, the pressure loss of the filter 25 increases, the load on the engine, which is an internal combustion engine, increases, and in the worst case, the engine stops. Therefore, it is necessary to collect particulates at an appropriate time to remove particulates.
The means for determining the appropriate timing is based on the detection of the pressure loss level of the filter, the detection of the amount of trapped particulates by the electric means, or the integrated value of the operating state of the engine.

Next, the basic process of filter regeneration will be described. When the particulate collection amount in the filter 25 reaches the collection amount region where the regeneration is to be performed, the filter regeneration process starts.

This reproduction control command is issued from a control unit (not shown) which is a component of the present apparatus. The valve 34 is first opened based on a command from the control unit, and subsequently the valve 33 is closed. As a result, the exhaust gas is guided to the exhaust branch pipe 32. At this time, the exhaust gas stops flowing into the heating chamber 24, so that the check valve 31 provided in the air guide tube 30 is opened. Next, the microwave generating means 26
Is supplied with driving power, and the generated microwave is
8 is transmitted to the heating chamber 24 from the exhaust gas inflow side of the filter 25. And the heat radiation prevention part 22 is provided.
The particulates present near the end face of the filter 25 are heated more strongly than the particulates in other regions. At this time, the heat radiation preventing part 22 provided in the filter 25 is provided.
Heat radiation from the heated path Tikyureto microwave is suppressed so acts to suppress the dissipation of heat to the heating chamber 24 (heat insulating effect) are. By this action, the rate of temperature rise of the particulates can be increased, and the particulates can reach the combustible temperature in a short time. As a result, the filter regeneration apparatus of the present invention can practically supply the driving power for the microwave generation source from the power supply mounted on the automobile.

When the particulate reaches the combustible temperature, air is supplied to the filter 25 from the exhaust gas inflow side by the air supply means 29. When the air is supplied, the particulates that have reached the combustible temperature shift to the combustion state. Conventionally, when air is supplied, the particulates present near the end face of the filter are cooled by this air , and the unburned portion does not reach the combustible temperature temperature due to the large heat dissipation of the combustion heat. Many remained. However, in the present invention, since the heat radiation preventing portion 22 provided on the side of the filter 25 to which air is supplied acts to prevent heat radiation, cooling near the end face of the filter 25 due to the supply of air is suppressed and combustion is started. Heat dissipation near the end face of the filter 25 is suppressed, and that portion can be kept at a high temperature, so that the particulates near the end face of the filter which have conventionally remained can be almost completely burned. As a result, in the filter regeneration device of the present invention, the accumulation of particulates near the end face of the filter 25 is suppressed, and the clogging of the through hole 19a into which the exhaust gas flows is prevented, so that the continuous collection and regeneration of the particulates is continued. In the repetition, it is possible to prevent the collection performance and the regeneration performance of the filter 25 from deteriorating, and to maintain the performance permanently.

The burning of the particulates in the filter 25 moves in the direction of air flow, but the vicinity of the end face of the filter 25 on the side of the radiation prevention unit 22 where the combustion is completed is the radiation prevention unit 2.
2, heat dissipation is suppressed, so there is little decrease in temperature,
Since the temperature difference between the part heated by the particulate combustion and the part heated by the particulate matter can be reduced, cracks in the filter due to thermal distortion can be prevented. As a result, the initial collection performance of the filter 25 can be maintained.

Since the heat radiation preventing portion 22 is provided on the end face of the filter 25, it is integrated. Therefore, since the through hole 19 of the heat radiation preventing part 22 and the one of the filter 25 communicate with each other, the inflow of the exhaust gas and the supply of the air can be smoothly performed. It's easy.

The check valve 31 air supply means 29 supplies air when the filter regeneration is completed is stopped is closed. Thereafter, 33 and 34 are controlled, and the state shown in FIG. 2 is reached, and the exhaust gas flows into the filter 25 to collect particulates.

FIG. 3 shows the configuration of a filter regeneration device for an internal combustion engine according to another embodiment of the present invention. 2, the same members or the same functional members as those in FIG. 2 are indicated by the same numbers. Numeral 38 denotes air supply means for supplying air to the heating chamber 24. The air supply means 38
6 also serves as the cooling means. This air is supplied to the open / close valve 39
Is controlled, the inflow into the waveguide 40 is performed, and the fluid flows through the waveguide 40 and is guided to the heating chamber 24. 4
Reference numeral 1 denotes a connecting pipe, which is a discharge path for air and particulate combustion exhaust gas. Reference numeral 42 denotes a punching hole provided on the wall surface of the waveguide 40, and has a function of shielding air from flowing through and a microwave.

The exhaust gas flows through the exhaust pipe 23 from the direction indicated by the arrow in the drawing and flows into the filter 25. The difference from FIG. 2 is that the heat radiation preventing portion 22 provided on the filter 25 is arranged so as to be on the exhaust gas outflow side, and the air required for combustion from the side on which the exhaust gas flows out in the regeneration of the filter 25. /> And burn the particulates from the exhaust gas outflow side.

In the regeneration process having the above configuration, conventionally,
Due to the cooling effect of air and the large heat dissipation of the combustion heat of the particulates, the combustible temperature is not reached. As a result, the particulates near the end face of the filter 25 on the exhaust gas outflow side remain, and the filter collection volume decreases. Therefore, there is a problem that the collecting performance as a filter is reduced. However, in the present invention, since the heat radiation preventing portion 22 is provided on the end face of the filter 25 on the exhaust gas outflow side, that is, on the side supplying air , cooling of the vicinity of the end face of the filter 25 by air is suppressed by the heat insulating effect of the heat radiation preventing portion 22. At the same time, heat dissipation toward the heat radiation prevention part 22 is suppressed, and the temperature near the end face of the filter 25 can be kept high. As a result, the unburned particulates in the vicinity of the end face of the filter 25, which have been conventionally left, can be almost completely burned, so that the collection performance of the filter 25 can be prevented from lowering, and the initial performance can be maintained. it can.

As in the configuration shown in FIG. 2, the presence of the heat radiation preventing portion 22 allows the particulates to reach the combustible temperature in a short time, and the driving power source for the microwave generation source is changed from the power source mounted on the vehicle. It can be supplied practically and can prevent the filter from cracking due to thermal distortion.

In the configurations shown in FIGS. 2 and 3, the heat radiation preventing portions 22 may be provided at both ends of the filter 25, and when provided at either end, it is preferable to provide them at the air supply side.

It is not necessary to continue the operation of the microwave generating means 26 until the burning of the particulates in the entire area of the filter is completed, but at an appropriate time after the particulate present near the end face of the filter has shifted to the burning state. It can be turned off or the microwave power can be reduced. On the other hand, the air circulation time is continued until the regeneration of the entire filter is completed.

In order to perform the regeneration more effectively, another heating means may be provided to heat the air .

[0040]

As described above, the filter regeneration apparatus for an internal combustion engine according to the present invention has a structure in which a heat radiation preventing portion having a heat radiation preventing function is provided at least at one end of the filter on the air supply side. Is obtained. (1) Since heat dissipation from the filter containing the heated particulates is suppressed, the rate of temperature rise can be increased, and the particulates can reach the combustible temperature in a short time. As a result, it is possible to shorten the power supply time of the microwave required for raising the particulates to the combustible temperature, and it is possible to easily realize that the power supply for driving the microwave generation means is supplied from the vehicle power supply. The durability of the automobile power supply can be maintained. (2) Even if air necessary for combustion is supplied to the filter from the exhaust gas inflow side, cooling by air is suppressed, the combustible area of the particulate is expanded, and the particulate collected near the filter end face is almost completely removed. Can be burned. As a result, in the continuous repetition of collection and regeneration of particulates, accumulation of the particulates in the vicinity of the filter end face is prevented, and the exhaust gas flow holes are not blocked, and the collection performance and regeneration performance of the filter are deteriorated. Can be prevented. (3) On the other hand, even if air required for combustion is supplied to the filter from the exhaust gas outlet side, cooling by air near the filter end face is suppressed, and heat dissipation of combustion heat from near the filter end face that has started combustion is suppressed. Thus, the filter temperature can be kept high. As a result, the particulates in the vicinity of the filter end face can be almost completely burned, so that the collection capacity of the filter is not reduced, and a decrease in the collection performance can be prevented. (4) Cooling is suppressed in the vicinity of the filter end face where combustion has been completed, so that the temperature difference between the filter and the portion that has become hot due to the burning of particulates can be reduced, and cracks in the filter due to thermal distortion can be prevented. You. As a result, a decrease in the trapping performance of the filter can be prevented, the initial performance can be maintained, and a filter regeneration device with excellent durability can be obtained. (5) Since the heat radiation preventing portion is provided on the end face of the filter, it is integrated. Accordingly inflow and empty the exhaust gas is in communication with that of the through hole and the filter of the heat radiation preventing portion
The supply of air can be performed smoothly, and when it is arranged in the heating chamber, winding and mounting of the heat insulating material become easy.

[Brief description of the drawings]

FIG. 1 (a) Filter regeneration for an internal combustion engine in an embodiment of the present invention
Plan view of a filter applied to the device (b) Cross-sectional view of the filter

FIG. 2 is a configuration diagram of an internal combustion engine filter regeneration device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a filter regeneration device for an internal combustion engine according to another embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional filter regeneration device for an internal combustion engine.

FIG. 5 is a plan view and a sectional view of a conventional filter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 19 Through hole 20 1st sealing plug 21 2nd sealing plug 22 Heat dissipation prevention part 23 Exhaust pipe 24 Heating chamber 25 Filter 26 Microwave generation means 27 Cooling means 28 Waveguide 29 Air supply means 30 Wind guide tube 31 Check valve 32 Exhaust branch pipe 33, 34 Valve 35, 36 Microwave shut-off means 37 Insulation material 38 Air supply means and cooling means 39 Opening / closing valve 40 Waveguide 41 Connecting pipe 42 Punching hole

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takahiro Matsumoto 1006 Kazuma Kadoma, Kadoma City, Osaka Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-59-126022 (JP, A) JP-A-59- 28010 (JP, A) JP-A-61-138812 (JP, A) Japanese Utility Model Application Laid-Open No. 2-92019 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F01N 3/02 301- 341

Claims (1)

(57) [Claims] A heating chamber provided in an exhaust pipe for discharging exhaust gas of the internal combustion engine; a microwave generating means for generating a microwave for supplying power to the heating chamber; and the internal combustion engine housed in the heating chamber. And a filter for trapping particulates contained in the exhaust gas, and supplying air to the heating chamber.
An air supply means, wherein the filter comprises a honeycomb structure having a large number of through-holes formed by porous ceramic partitions surrounded by an outer frame, and one end of the through-hole is provided in a direction adjacent to one end of the through-hole. A first sealing plug made of a ceramic cement material having an airtightness in the through-holes that are present at intervals of the interval and a through-hole not provided with the first sealing plug at the other end of the through-hole are airtight. position provided with a second sealing plug made of ceramic cement, the first sealing plug side for supplying air to the inside of the end face of the through hole of the honeycomb structure by the air supply means having a Then, a heat radiation preventing portion integral with the honeycomb structure is provided ,
So that the heat radiation preventing portion of the filter is on the air supply means side.
Filter regeneration device for an internal combustion engine arranged in a vehicle.