JP2820040B2 - 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 collecting particulates (particulate matter) contained in exhaust gas discharged from a diesel engine (internal combustion engine). More specifically, the present invention relates to a filter regeneration device for an internal combustion engine that regenerates the trapping performance of a filter by removing trapped particulates by heating and burning, and more specifically, a branch path through which exhaust gas flows during regeneration. It relates to the configuration of the tube.

[0002]

2. Description of the Related Art Diesel engines are characterized by high combustion efficiency and excellent durability as compared with gasoline engines, but have the disadvantage of emitting a large amount of air pollutants. Exhaust gas emitted by diesel engines contains nitrogen oxides, as well as particulates that are responsible for respiratory illness, and exhaust gas regulations are being tightened. Particulates are mainly SOF (Sol
The method of treating these particulates in the exhaust system includes an oxidation catalyst method to reduce SOF and a method of collecting particulates using a filter. However, in the oxidation catalyst method, the filter method is preferable because the soot cannot be reduced. However, if the filter system continues to collect particulates, the filter will become clogged and the flow of exhaust gas will deteriorate, leading to a decrease in engine output or engine shutdown. The technology for regenerating is being developed, and securing a durable performance is a major practical issue. As a method of regenerating the trapping performance of the filter, a method of burning and removing particulates in the filter and a method of supplying high-pressure air to the filter and blowing off the particulates to the outside of the filter to burn and remove the particulates have been proposed and advanced. However, the method of processing outside the filter has a problem in that particulates are completely removed, and the mainstream of the regeneration method is a method of burning and removing inside the filter.

[0003] It is known that particulates burn from about 600 ° C. As means for generating energy for raising the particulates to this high temperature range, a burner method, an electric heater method, or a microwave method is used. However, as a filter regeneration apparatus using a microwave heating method, for example, Japanese Patent Application Laid-Open No. 61-11 / 1986
No. 416, and FIG. 7 shows an apparatus disclosed in the publication. In FIG. 7, 1 is an engine, 2 is an exhaust pipe,
3 is a filter, 4 is a microwave heating space, 5 is a microwave generating means (magnetron) as a heating means, 6 is a microwave leakage preventing means for limiting the microwave heating space 4,
Reference numeral 7 denotes a microwave supply path for transmitting microwaves generated by the magnetron to the microwave heating space 4, and reference numerals 8 and 9 denote incident waves to the microwave heating space 4 provided in the microwave supply path 7 and light from the heating space 4. Detecting means 10 for detecting the reflected wave is a control device that controls the operation of the magnetron 5 based on the microwave incident wave, the reflected wave, and the signal of the engine operation time.

[0004] In the above configuration, the particulates contained in the exhaust gas of the engine 1 are collected by the filter 3 when flowing through the filter 3. The amount of particulates collected by the filter 3 increases with the passage of time. In this process, the magnetron 5 is operated at a constant cycle by an output signal of the control device 10. The microwave generated by the magnetron 5 enters the heating space 4 and the filter 3
From the exhaust gas inflow side to the inside of the filter 3 and reaches the wall of the heating space 4 on the downstream side, where it is reflected and returns to the magnetron 5 via the filter 3 again. In this microwave transmission, a signal of an incident wave into the heating space 4 and a signal of a reflected wave from the heating space 4 are detected, and a change in microwave characteristics of the entire heating space 4 is detected based on these signals. Measured as

If the amount of particulates collected in the filter 3 becomes too large, the load on the engine increases, and in the worst case, the engine stops, so it is necessary to remove the particulates at an appropriate time. The lower limit value of the voltage standing wave ratio corresponding to this appropriate time, that is, at the time of collecting an appropriate amount of particulates, is stored in the control device 10.

When the voltage standing wave ratio obtained from the detected signal falls below the lower limit of the stored voltage standing wave ratio, the output of the magnetron 5 is increased. Since this microwave is supplied from the exhaust gas inflow side of the filter 3, the particulates collected by the filter 3 and deposited on the exhaust gas inflow side of the filter 3 are strongly heated by dielectric heating. The particulate heated after an appropriate heating time rises to a combustible temperature zone. When the temperature reaches this temperature range, the particulates shift to a combustion state due to oxygen contained in the exhaust gas. This combustion region moves in the exhaust gas flow direction of the filter 3 and finally the filter 3
It burns and removes the particulates deposited on the surface.

[0007] Completion of combustion removal is determined based on the fact that the voltage standing wave ratio during the particulate combustion period has exceeded a predetermined upper limit, and the operation of the magnetron 5 has been stopped.

[0008]

However, the above-mentioned conventional apparatus has the following problems when dielectrically heating and burning the particulates.

The region where the particulates are intensely dielectrically heated is on the exhaust gas inflow side of the filter, and the particulates deposited on the filter end face on the inflow side and in the vicinity thereof are heated up to a temperature zone where transition to a combustion state is possible. Is difficult to do. This is because the air near the filter end face is difficult to heat, and the air temperature is very low compared to the temperature inside the filter. This is because the temperature does not rise. This problem suggests that it is difficult to remove and remove the particulates accumulated on the exhaust gas inflow side of the filter, thereby accumulating the particulate accumulation on the filter exhaust gas upstream side. As a result, the flow of exhaust gas is obstructed, which may cause an abnormal operation of the engine.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is intended to ensure regeneration of filter collecting performance in a device for burning and removing particulates collected by a filter in a direction opposite to a flow direction of exhaust gas. It is another object of the present invention to provide a configuration of a branch path pipe through which exhaust gas flows when regeneration of a filter is performed.

[0011]

In order to achieve the above object, a filter regeneration device for an internal combustion engine according to the present invention has the following configuration.

That is, the filter that collects the particulates is subjected to microwave generation in a direction opposite to the exhaust gas flow direction.
In an apparatus for feeding and reproducing microwaves from a raw means, an exhaust inlet pipe for flowing exhaust gas is formed upstream of the filter, and an exhaust outlet pipe for opening to the atmosphere is formed downstream of the filter. And an inlet branch pipe and an outlet branch pipe that bypass the exhaust inlet pipe and the exhaust outlet pipe.
The downstream wall of the filter is connected to the connection surface of the rectangular waveguide to form a series of branch path tubes.

In the filter, an upstream wall and a downstream wall supporting the filter are detachably connected to an exhaust inlet pipe side and an exhaust outlet pipe side via a gasket, and a part of the branch path pipe is connected to the filter. It was configured to be integrally formed between the upstream wall and the downstream wall .

[0014] Further, a large number of bellows portions are formed in the branch path tube.

[0015]

The present invention has the following functions by the above-described configuration.

That is, in the filter regeneration device for an internal combustion engine of the present invention, a series of branch path pipes are connected by connecting at least one pair of branch pipes that bypass between the upstream and downstream of the filter through which exhaust gas flows. This guarantees that the flow path of the exhaust gas at the time of regeneration is ensured simply by connecting the connection surfaces.

Also, by forming a part of the branch path pipe integrally between the upstream wall and the downstream wall supporting the filter,
When the filter needs to be replaced due to its service life, there is no need to remove and attach another branch pipe, so there is no simple mistake such as forgetting to attach or forget to tighten, and the focus is only on replacing the filter unit. While being able to
The replacement of the filter unit can be completed with the minimum necessary parts replacement.

Further, by forming a large number of bellows on the necessary branch pipe, the bellows can be extended, so that assembly dimensional errors caused by stacking components in the direction of flow of exhaust gas can be reduced by the bellows. The correction can be easily absorbed.

[0019]

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 are block diagrams of a filter regeneration apparatus for an internal combustion engine showing one embodiment of the present invention.
FIG. 2 shows an operation state when particulates are collected in the filter, and FIG. 2 shows an operation state when the filter is regenerated.

1 to 3, reference numeral 11 denotes an internal combustion engine (diesel engine), 12 denotes an exhaust pipe for discharging exhaust gas from the internal combustion engine 11, and 13 denotes an exhaust inlet pipe connected to the exhaust pipe 12. The other is connected to the heating space 14. Reference numeral 15 denotes a filter having a honeycomb structure for trapping particulates contained in the exhaust gas while the exhaust gas passes therethrough. Upstream / downstream walls 18 and 19, which are connection surfaces that support the upper and lower sides of the outer periphery of 17, are connected to the heating space 14 by the upstream wall 18.

Reference numeral 20 denotes microwave generating means (heating means) for generating microwaves for feeding the heating space 14 for dielectric heating of the particulates, and reference numerals 21 and 22 denote the microwaves generated by the microwave generating means 20 respectively. A linear and annular rectangular waveguide for transmitting to the heating space 14 is connected to a downstream wall 19 of the filter 15 via a gasket 23 for suppressing exhaust gas from being discharged into the atmosphere. 24 and (25) are two power supply holes for supplying microwaves to the heating space 14. 26 is the rectangular waveguide 22
A gas supply means 27 (referred to as A / P in the figure) for generating a gas containing oxygen to be supplied to the heating space 14 in the middle of the exhaust outlet pipe which is connected to the other of the above and which opens the outlet to the atmosphere; A first valve 28 for controlling the flow of the gas containing oxygen to the filter 15 and a second valve 30 for opening and closing the flow hole 29 are provided. Reference numerals 31 and 32 denote microwave shielding means having a punching hole configuration, a honeycomb configuration, or the like, which limits a space for substantially confining microwaves.

Reference numeral 33 denotes a branch passage pipe branched from the exhaust inlet pipe 13 and a discharge port for gas flowing through the filter 15 at the time of filter regeneration, and a flow passage whose outlet is opened and closed by the second valve 30. The exhaust outlet pipe 26 through the hole 29
To join. The branch path pipe 33 includes an inlet branch pipe 34 and an outlet branch pipe 35. The branch path pipe 33 is connected to the filter downstream wall 19, which is a connection surface located at a substantially intermediate portion, on one surface of the rectangular waveguide 22, and is connected to a series. A branch path tube 33 is formed.

An exhaust gas switching valve 36 controls the flow of the exhaust gas to the exhaust branch pipe 37, and a muffler 38 opens to the atmosphere.

Reference numeral 39 denotes a microwave detecting means disposed in the exhaust gas non-flow space of the filter 15 for detecting the amount of microwaves present in the vicinity of the installation space by the operation of the microwave generating means 20; Disposed in the inlet pipe 13,
When the internal combustion engine 11 is operating, the temperature of the exhaust gas is
5 is a temperature detecting means for detecting the temperature of the gas flowing through the filter 15 when the regeneration is performed.
At the same time, the detection signal is input to control means 41 which is an electronic control unit (denoted as ECU in the figure). Reference numeral 42 denotes a driving motor (referred to as Mv in the figure) as driving means for the first and second valves 28 and 30, and reference numeral 43 denotes a driving power supply for the microwave generating means 20.

The control means 41 has a trapping amount determination map defined in advance, and stores in advance a lower limit value and an upper limit value of the trapping amount that permits the filter 15 to regenerate the trapping performance. . The microwave generation means 20 is periodically operated during the operation of the internal combustion engine 11, and the amount of microwaves detected by the microwave detection means 39 and the integrated value of the operation time of the internal combustion engine 11 at the time of the detection. Is compared with the collection amount map to determine the current collection amount. The control means 41 controls the operation of the microwave generation means 20, the gas supply means 27, and the drive motor 42 when the current collection amount is within the collection amount range in which the regeneration of the filter 15 is permitted.

Next, the flow of exhaust gas will be described. During the period in which particulates are collected by the filter 15, that is, during normal operation of the internal combustion engine 11, the exhaust gas switching valve 36 is shut off, and the first valve is closed. 28 is controlled to a flow state, and the second valve 30 is controlled to a shut-off state, so that the exhaust gas flows to the filter 15.

During the operation of the internal combustion engine 11 during the regeneration period of the filter 15, the exhaust gas switching valve 36 is controlled to flow through, so that the exhaust gas flows through the exhaust branch pipe 37 and the first valve 28 is controlled to a shut-off state, the second valve 30 is controlled to a flowing state, and after the temperature of the particulates is increased by the microwave generating means 20, the gas supply means 27 is operated to filter the gas for promoting the combustion of the particulates. 15, the particulates are burned and removed, and the exhaust gas is passed through the branch passage pipe 3.
3. It is discharged to the atmosphere through the through hole 29.

In the above configuration, the inlet branch pipe 3 that bypasses between the upstream and downstream of the filter 15 through which the exhaust gas flows.
4 and the outlet branch 35 are connected by a connecting part, i.e., the connecting surface of the filter downstream wall 19 and the rectangular waveguide 22, to form a series of branch path pipes 33.
It is possible to guarantee the flow path of the exhaust gas at the time of the regeneration only by the connection of (9, 22).

Next, another embodiment of the present invention will be described with reference to FIGS. 4 and 5 are different from the above-described embodiment in that one of them is not provided with the exhaust branch pipe 37, and the regenerating apparatus having such a configuration has the filter 15 only when the internal combustion engine 11 is not operating. Execute playback. FIG.
The parts having the same functions and the same functions as those described above are denoted by the same reference numerals and the description thereof is omitted.

One of the differences is that the upstream wall 18 and the downstream wall 19 supporting the filter 15
4. The rectangular waveguide 22 is detachably connected to the rectangular waveguide 22 via a gasket 23 for suppressing exhaust gas emission to the atmosphere, and a part 45 of the branch path pipe is newly connected to the upstream / downstream walls 18, 1
9 is formed integrally, and a series of branch path pipes 33 are constituted by three of the inlet branch pipe 34, a part 45 of the branch path pipe, and the outlet branch pipe 35. Since only the filter unit can be attached and detached, When the filter 15 needs to be replaced due to its service life or the like, there is no need to remove and attach the other inlet branch pipe 34 and outlet branch pipe 35. Therefore forgot both branch pipes (34, 35), it is not at all occur a simple mistake such as forgetting to fasten, it is possible to concentrate on the replacement of the filter units, replacement of the filter unit is minimum required It can be completed by replacing parts.

FIG. 5 is a configuration diagram when the filter unit is removed. In FIG. 6, the point different from the above-described embodiment is that a large number of bellows portions 46 are formed in the outlet branch pipe 35, and assembling parts in the flow direction of the exhaust gas causes assembly dimensional errors and variations. Also, by forming the outlet branch pipe 35 having the bellows section 46 shorter than a predetermined dimension, the bellows section 46, that is, the outlet branch pipe 35, extends in the flow direction of the exhaust gas at the time of mounting, and easily absorbs and corrects. Can be.

[0033]

According to the filter regeneration apparatus for an internal combustion engine of the present invention as described in the above embodiment, the following effects can be obtained.

(1) Upstream of the filter through which exhaust gas flows
The branch pipe that bypasses between the filter and the downstream
By forming a series of branch path pipes by connecting them at the connection surfaces of the shaped waveguides, it is possible to guarantee the flow path of the exhaust gas at the time of regeneration by simply connecting the connection parts.

(2) By forming a part of the branch path pipe integrally between the upstream wall and the downstream wall supporting the filter,
When the filter needs to be replaced due to its service life, there is no need to remove and attach another branch pipe, so there is no simple mistake such as forgetting to attach or forget to tighten, and the focus is only on replacing the filter unit. While being able to
The replacement of the filter unit can be completed with the minimum necessary parts replacement.

(3) By forming a large number of bellows on a required branch pipe, the bellows can be extended, so that assembly dimensional errors and variations caused by stacking parts in the flow direction of exhaust gas can be reduced. Correction and absorption can be easily performed at the bellows.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an operation state at the time of collection of a filter regeneration device for an internal combustion engine in one embodiment of the present invention.

FIG. 2 is a configuration diagram showing an operation state of the internal combustion engine filter regeneration device during filter regeneration.

FIG. 3 is an enlarged configuration diagram of a main part of FIGS. 1 and 2;

FIG. 4 is a block diagram showing an operation state of a filter regeneration device for an internal combustion engine according to another embodiment of the present invention at the time of filter regeneration.

FIG. 5 is a configuration diagram of the internal combustion engine filter regeneration device when a filter unit is removed.

FIG. 6 is a block diagram showing another embodiment of the present invention.

FIG. 7 is a configuration diagram of a conventional filter regeneration device for an internal combustion engine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 13 Exhaust inlet pipe 14 Heating space 15 Filter 18 Upstream wall 19 Downstream wall 22 Rectangular waveguide (connection surface) 23 Gasket 26 Exhaust outlet pipe 33 Branch path pipe 34 Inlet branch pipe 35 Exit branch pipe 45 Part of branch path pipe 46 Bellows

──────────────────────────────────────────────────続 き Continued on the front page (72) Takahiro Matsumoto, Inventor 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-59-28009 (JP, A) JP-A-5-106428 (JP, A) JP-A-64-87814 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01N 3/02 301-341

Claims (3)

(57) [Claims] 1. A filter that collects particulates is removed from a microwave generating means in a direction opposite to a flow direction of exhaust gas.
In an apparatus for feeding and reproducing microwaves, an exhaust inlet pipe for flowing exhaust gas is formed on the upstream side of the filter, and an exhaust outlet pipe for opening to the atmosphere is formed on the downstream side of the filter. The inlet branch pipe and the outlet branch pipe that bypass the exhaust inlet pipe and the exhaust outlet pipe are
A filter regeneration device for an internal combustion engine, wherein a filter is connected to a downstream wall at a connection surface of a rectangular waveguide to form a series of branch path tubes. 2. A filter, comprising: an upstream wall supporting the filter;
Each downstream wall and, thereby detachably connected to the exhaust inlet pipe side via the exhaust outlet pipe side and the gasket, branch path
The filter regeneration device for an internal combustion engine according to claim 1, wherein a part of the pipe is formed integrally between the upstream wall and the downstream wall . 3. The filter regeneration device for an internal combustion engine according to claim 1, wherein a plurality of bellows portions are formed in the branch path pipe.