JPH04298624A - Filter regeneration device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a filter regeneration device for removing fine particles including carbon in exhaust gas of an internal combustion engine which has an excellent regeneration efficiency with capability of burning fine particles deposited in a filter in an energy saving manner and an excellent reliability of maintaining collection and regeneration performance continuously. CONSTITUTION:A filter regeneration device for an internal combustion engine is composed of filters 13, 14, cavities 15, 16, electric heaters A19, 20, fluid supply means 21, and fluid heating electric heater B22. When the filter 14 collects fine particles, the heater A20 is energized regularly, and fluid supplied to the cavity 16 by means of the fluid supply means 21 including oxygen at the time of regeneration is heated with the heater B22, thereby the temperature of fine particles deposited in the filter 14 is controlled at all times to thus improve regeneration characteristics.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter regeneration device for removing particulates containing carbon from exhaust gas of an internal combustion engine.

0002

[Prior Art] Conventionally, filters for collecting particulates in the exhaust gas of internal combustion engines (particularly diesel engines) and devices for removing and regenerating particulates accumulated in the filters have been used to prevent air pollution and to protect the environment. As exhaust gas regulations become stricter year by year, various studies are being carried out in an effort to maintain safety, and filters are available in foam types and monolithic types, depending on their configuration, and the heat source for regenerators is oil burners, oil burners, etc.
In addition to electric heaters, ideas have been made to use microwaves, but these have not been put to practical use.

A conventional example (Japanese Unexamined Patent Publication No. 1-290910) using microwaves as a heat source will be explained below with reference to FIG. In the same figure, 1 is the engine, 2 and 3 are TM01
A cylindrical cavity resonator in which the p-mode is excited; 4, a microwave radiation antenna; 5, a waveguide; 6, a microwave generating means; 7, a filter for collecting particulates on a porous ceramic partition wall; 8; is the exhaust gas flow switching valve. In such a configuration, spaces 9 and 10 are provided between the filter, which is disposed approximately at the center of the cavity resonator in the tube axis direction, and both end surfaces of the cavity resonator, respectively.

Microwaves generated by the microwave generating means 6 pass through the waveguide 5 and are fed to the cavity resonator 2 or 3 from the radiation antenna 4 protruding into the spaces 9 and 10. The particulates collected on the porous ceramic partition walls of the filter are dielectrically heated by the supplied microwaves, and when the temperature reaches about 600° C., they are ignited and burned, and the filter is regenerated.

[0005]

However, in this configuration, when the engine 1 is operated, the exhaust gas flow hits the partition wall of the filter 7, and particulates contained in the exhaust gas are deposited on the partition wall. The temperature of the accumulated particulates depends on the temperature of the exhaust gas, but the exhaust gas temperature of the engine 1 not only changes greatly depending on the operating conditions (rotation speed, load), but also the components of the particulates, and the ignition temperature during regeneration, It also affects combustion temperature. Therefore, optimal regeneration control is required using the energy given during regeneration to raise the temperature and the means for supplying a fluid containing oxygen for oxidation and combustion. When regenerating particulates at a low temperature, it is necessary to supply heating energy for a long period of time to forcibly raise the temperature to the ignition temperature, which requires a large amount of energy and is difficult to install when installed in a car. It is not economical as it requires a large-capacity battery, dynamo, or alternator, and if the regeneration is completed in a short time, it is possible to release exhaust gas into the atmosphere during the regeneration time, but if the time required for regeneration becomes longer, the exhaust gas will be released separately. A filter is also required. In addition, even if the particulates are heated by a heating heat source, if they are cooled by the combustion fluid, the particulates at that location will not be regenerated because the temperature will rise and oxygen will diffuse and there will be no combustion growth. When collecting particulates during regeneration, the pressure loss of the filter increases in the unregenerated part, which not only impedes good engine operation but can even lead to clogging.
There was a risk that the filter function would be completely lost. In addition, when microwaves are used as the heating heat source, in order to prevent the microwaves from leaking outside the cavity resonators 2 and 3, shielding plates such as punched plates that shield the microwaves should be installed in the exhaust gas and fluid passages. This creates an uneven fluid flow and prevents the particulates from rising in temperature.

Therefore, the present invention provides a highly reliable filter regeneration device for an internal combustion engine that can burn particulates reliably in a short time regardless of the operating conditions of the internal combustion engine, has high heating efficiency, and can continuously maintain regeneration ability. is intended to provide.

[0007]

[Means for Solving the Problems] In order to achieve the object, the internal combustion engine filter regeneration device of the present invention uses a heat source that heats and burns particulates and introduces an exhaust gas flow into the filter to collect the particulates. The configuration is such that it operates periodically while the system is running.

Further, the filter regeneration device for an internal combustion engine of the present invention operates a heat source for heating and combusting particulates periodically while introducing an exhaust gas flow into the filter and collecting particulates. When regenerating the filter by oxidizing and burning particulates, the exhaust gas flow is cut off and only fluid from the fluid supply means is supplied to the cavity in which the filter is housed.

Further, the filter regeneration device for an internal combustion engine of the present invention includes a first heat source for heating and burning particulates, and a fluid supply means for introducing into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. a second heat source is provided in the fluid passage connecting the fluid supply means and the filter, and when the particulates are oxidized and burned to regenerate the filter, the second heat source heats the fluid supplied to the filter. It is configured to do this.

The filter regeneration device for an internal combustion engine of the present invention also includes a first heat source for heating and burning particulates, and a fluid supply means for introducing into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. A second heat source is provided in the fluid passage connecting the fluid supply means and the filter, and at least one of the two heat sources is constituted by dielectric heating means using microwaves to oxidize and burn the particulates and heat the filter. During regeneration, the fluid supplied to the filter is heated by a second heat source.

The internal combustion engine filter regeneration device of the present invention also includes a microwave oscillator that dielectrically heats and burns particulates, and a fluid supply means that introduces into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. a microwave heating element having holes is provided in a fluid passage connecting the fluid supply means and the filter, and when particulates are oxidized and burned to regenerate the filter, the microwave heating element supplies the fluid to the filter. The structure is such that the fluid heated is heated.

The internal combustion engine filter regeneration device of the present invention also includes a microwave oscillator that dielectrically heats and burns particulates, and a fluid supply means that introduces into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. A microwave heating element having holes is provided in a cavity wall on a fluid passage connecting the fluid supply means and the filter, and when regenerating the filter by oxidizing and burning particulates, the microwave heating element The fluid supplied to the filter is configured to be heated.

[0013]

[Operation] The filter regeneration device for an internal combustion engine of the present invention is configured to periodically operate a heat source for heating and combusting particulates while introducing an exhaust gas flow into the filter and collecting particulates. Therefore, when collecting particulates, that is, when the engine is running, the particulates are preheated by a heat source, so the temperature of the particulates is kept constant at the start of regeneration without placing a burden on the power supply and regardless of engine operating conditions. can be controlled.

Further, the filter regeneration device for an internal combustion engine of the present invention operates a heat source for heating and combusting particulates periodically while introducing an exhaust gas flow into the filter and collecting particulates. When particulates are oxidized and burned to regenerate the filter, the exhaust gas flow is cut off and only fluid from the fluid supply means is supplied to the cavity that houses the filter. During operation, the particulates are preheated by a heat source in advance, so there is no burden on the power supply, and the temperature of the particulates is already raised to a certain level when regeneration starts.Also, during regeneration, the particulates are changed to exhaust gas with a low oxygen concentration and low temperature. The filter can be efficiently regenerated by supplying a fluid containing oxygen.

Further, the filter regeneration device for an internal combustion engine of the present invention includes a first heat source for heating and burning particulates, and a fluid supply means for introducing into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. a second heat source is provided in the fluid passage connecting the fluid supply means and the filter, and when the particulates are oxidized and burned to regenerate the filter, the second heat source heats the fluid supplied to the filter. Because of this structure, during regeneration, a fluid containing preheated oxygen is supplied, so that the oxidation combustion reaction is promoted without cooling the particulates heated by the first heat source, and the filter can be regenerated efficiently. can.

Further, the filter regeneration device for an internal combustion engine of the present invention includes a first heat source for heating and burning particulates, and a fluid supply means for introducing into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. A second heat source is provided in the fluid passage connecting the fluid supply means and the filter, and at least one of the two heat sources is constituted by dielectric heating means using microwaves to oxidize and burn the particulates and heat the filter. During regeneration, the second heat source heats the fluid supplied to the filter, so the heat source is not directly exposed to exhaust gas or oxygen-containing fluid, so the heat source components are not oxidized and corroded, improving durability. do. Additionally, in the case of microwave heating, it does not directly affect the particulates dispersed in the exhaust gas, but only increases the temperature of the particulates deposited on the filter, so if it is used as the first heat source, the amount deposited on the filter will increase. The filter can be regenerated efficiently by easily applying appropriate heating energy.

The internal combustion engine filter regeneration device of the present invention also includes a microwave oscillator that dielectrically heats and burns particulates, and a fluid supply means that introduces into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. a microwave heating element having holes is provided in a fluid passage connecting the fluid supply means and the filter, and when particulates are oxidized and burned to regenerate the filter, the microwave heating element supplies the fluid to the filter. Since the microwave energy applied to the particulates deposited on the filter in the cavity is also radiated into the fluid passage, it is important to avoid using materials with high dielectric loss or microwave resistors in the area. If a microwave heating element such as a certain ferrite is installed, the load of the microwave oscillator becomes the microwave heating element in addition to the particulates, which can consume excess energy and increase the oscillation efficiency.In addition, during regeneration, pre-heated oxygen is included. Since the fluid is supplied, the oxidation combustion reaction is promoted without cooling the particulates heated by microwaves, and the regeneration efficiency of the filter is improved.

The internal combustion engine filter regeneration device of the present invention also includes a microwave oscillator that dielectrically heats and burns particulates, and a fluid supply means that introduces into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. A microwave heating element having holes is provided in a cavity wall on a fluid passage connecting the fluid supply means and the filter, and when regenerating the filter by oxidizing and burning particulates, the microwave heating element Since the configuration heats the fluid supplied to the filter, microwaves leaking into the fluid passage can be absorbed and attenuated by the microwave heating element provided on the cavity wall, and not only can microwaves be prevented from leaking out of the cavity, but also microwaves can be prevented from leaking out of the cavity. Since the fluid containing oxygen is heated by the heating element, the oxidation combustion reaction is promoted without cooling the particulates heated by microwaves, and the regeneration efficiency of the filter is improved.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A filter regeneration device for an internal combustion engine according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view of the system and main parts of FIG. 1; In the figure, 11 is an engine, 12 is a manifold that collects exhaust gas from a multi-cylinder engine, and 13 and 14 are filters that are installed in cavities 15 and 16 to collect particulates. The holes are alternately closed on the windward and leeward sides, and particulates accumulate on the partition walls when exhaust gas passes through them. 17 and 18 are spacers for insulating and buffering the filters 13 and 14. Reference numerals 19 and 20 refer to an electric heater A that is a heating source for the particulates; 21 refers to a fluid supply means containing oxygen necessary for combustion of the particulates; and 22 heats the fluid sent from the fluid supply means 21 to the cavities 15 and 16. Electric heater B is the second heat source. Inside the manifold 12 and cavities 15, 16
Sensors 23, 24, 25, 26, and 27 are provided before and after the engine 11 to detect the temperature or pressure at the relevant location, and the fuel consumption, rotation speed, etc. from the engine 11 are taken out as signals and input to the detection unit 28. That's what I do. 29 is a control valve A that selects which of the cavities 15 and 16 the exhaust gas of the engine 11 will be sent to, and 30 is a control valve B that selects which of the cavities 15 and 16 will be sent the fluid. Operate. 31 is an electric heater 19,
20, 22 are power supplies such as batteries and alternators that drive the fluid supply means 21, control valve A29 and control valve B30, and 32 is information from the detection unit 28 and a built-in timer and storage unit (none of which are shown). 33 is a calculation unit that compares and calculates data etc. stored in the calculation unit 32.
In response to the signal, the power supply 31, control valve A29, control valve B30
, the fluid supply means 21, the electric heaters A19 and 20, and the electric heater B22.

[0021] To explain the operation of the filter regeneration device for an internal combustion engine having the above structure, while the engine 11 is operating, exhaust gas containing particulates flows through the manifold 12.
The particulates flow through the control valve A29 into the filter 14 in the cavity 16, where particulates are removed by the partition wall of the filter 14, and then released into the atmosphere through the external exhaust pipe 34.

A sensor 23 installed in the manifold 12 detects changes in the temperature of the exhaust gas depending on the operating conditions of the engine 11, and detects whether or not the temperature has reached a predetermined temperature. The state of the particulates deposited on the filter 14 is determined by the calculation section 32, and the electric heater is periodically energized by the control section to ensure thermal stability of the particulates at the start of regeneration. In this way, the engine 11 is operated for a certain period of time, and the filter 14 is damaged due to the accumulation of particulates.
Since the pressure loss of the filter 14 increases and the engine 11 cannot maintain good operation, the pressure loss described above is detected and the filter 14 is regenerated. In the regeneration cycle, the control valve A29 switches the exhaust gas from the engine 11, so that the introduction into the cavity 16 is blocked, and instead the exhaust gas flows into the cavity 15.
The filter 13 starts collecting particulates. On the other hand, the electric heater 2 inside the cavity 16
0, continuous current is applied to burn the particulates, and the particulates near the front surface of the opposing filter are heated and heated. When it is detected that the particulates have reached the ignition temperature, the fluid supply means 21 starts discharging combustion fluid, and the electric heater that heats the fluid is also energized, and the control valve B supplies preheated fluid to the cavity 16. Combustion of particulates that starts near the front of the filter 14 reacts with oxygen in the fluid and gradually spreads toward the leeward side, and eventually the combustion ends and the filter 14 is regenerated. The power supply to the electric heater A20 may be stopped immediately after it is detected that the particulates are ignited. Further, the supply of electricity to the electric heater B22 is also stopped when the amount of heat generated due to expansion of combustion of particulates becomes large. When the regeneration of the filter 14 is completed in this way, if the pressure loss due to the accumulation of particulates on the filter 13 increases, exhaust gas is introduced into the filter 14 again and particulate collection is resumed. In this way, the filters 13 and 14
are collected and reproduced alternately.

FIG. 2 is a sectional view of the system and main parts of a filter regeneration device for an internal combustion engine in one embodiment of the present invention. In FIG. 2, 34 is a filter for collecting particulates provided in the cavity 35, which has a honeycomb shape and blocks adjacent through holes alternately on the windward and leeward sides, so that the exhaust gas does not pass through the partition wall. Particulates accumulate on the partition walls as they pass through. 36 is a spacer for insulating and buffering the filter 34. 37 is a magnetron that is a heating source oscillator that dielectrically heats the particulates; 38 is a waveguide that transmits the microwave oscillated by the magnetron 37 to the cavity 35; and 39 is a part of the cavity 35 to which the waveguide 38 is connected. It is an opening provided on the wall surface for radiating microwaves to the filter 34,
A plurality of them are provided around the cavity 35. Reference numeral 40 denotes a fluid supply means containing oxygen necessary for combustion of particulates, and 41 a ferrite, which is a material with a large dielectric loss or a microwave resistor, provided in the passage of the fluid sent from the fluid supply means 40 to the cavity 35. Microwave heating elements such as Exhaust gas from an engine (not shown) is introduced into the filter 34 from the X direction in the figure and deposits particulates. Once a certain amount of particulates have accumulated, a regeneration cycle begins. The magnetron 37 is driven and the oscillated microwaves are transmitted through the waveguide 38 and reach the cavity 3.
5. The material of the filter 34 that emits radiation to the filter 34 from the aperture group 39 provided around the periphery is generally made of porous ceramic, and has extremely low dielectric loss when used alone, but once particulates are deposited, it responds to the amount of deposited particulates. This creates a load on the microwave. When the particulates are irradiated with microwaves from the magnetron 37, their temperature gradually rises and eventually ignites. On the other hand, the microwave heating element provided in the fluid passage on the wall of the cavity 34 generates heat because it is exposed to the microwave electric field radiated to the cavity 35, and the fluid supplied to the cavity 35 by the fluid supply means 40 generates heat due to the microwave heating. Filter 3 is heated as it passes through the pores of the body.
The combustion of the particulates started by ignition reacts with the preheated oxygen-containing fluid, the combustion gradually expands, and eventually the filter 34 is regenerated.

[0024]

As described above, according to the internal combustion engine filter regeneration device of the present invention, the following effects can be obtained.

(1) Since the heat source for heating and combusting particulates is operated periodically while the exhaust gas flow is introduced into the filter and the particulates are being collected, the particulates can be collected easily. In other words, since the particulates are preheated by a heat source even when the engine is running, the temperature of the particulates can be controlled at a constant level at the start of regeneration without placing a burden on the power supply and regardless of the engine operating conditions. The playback rate will improve.

(2) A heat source for heating and burning the particulates is operated periodically while the exhaust gas flow is introduced into the filter to collect the particulates, and
When particulates are oxidized and burned to regenerate the filter, the exhaust gas flow is cut off and only fluid from the fluid supply means is supplied to the cavity that houses the filter. Sometimes, the particulates are preheated by a heat source in advance, so the particulates are heated to a certain level when regeneration starts without putting a burden on the power supply, and during regeneration, the particulates are changed to exhaust gas with a low oxygen concentration and low temperature. The filter can be efficiently regenerated by supplying a fluid containing oxygen.

(3) It has a first heat source for heating and burning the particulates, and a fluid supply means for introducing into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates, the fluid supply means and the A second heat source is provided in the fluid passage connecting the filters, and when the particulates are oxidized and burned to regenerate the filter, the second heat source heats the fluid supplied to the filter.
Since a fluid containing preheated oxygen is supplied during regeneration, the oxidation combustion reaction can be promoted without cooling the particulates heated to a raised temperature by the first heat source, and the filter can be regenerated efficiently.

(4) A first heat source for heating and burning the particulates; and a fluid supply means for introducing into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates, the fluid supply means and the A second heat source is provided in the fluid passage connecting the filter, and at least one of the two heat sources is configured with dielectric heating means using microwaves,
When regenerating the filter by oxidizing and burning particulates, the second heat source heats the fluid supplied to the filter, so the heat source is not directly exposed to exhaust gas or fluid containing oxygen, so the heat source components are The durability is improved without oxidation corrosion. Additionally, in the case of microwave heating, it does not directly affect the particulates dispersed in the exhaust gas, but only increases the temperature of the particulates deposited on the filter, so if it is used as the first heat source, the amount deposited on the filter will increase. The filter can be regenerated efficiently by easily applying appropriate heating energy.

(5) It has a microwave oscillator that dielectrically heats and burns the particulates, and a fluid supply means that introduces into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates, the fluid supply means and A microwave heating element having holes is provided in a fluid passage connecting the filter, and when regenerating the filter by oxidizing and burning particulates, the microwave heating element heats the fluid supplied to the filter. Since the microwave energy applied to the particulates deposited on the filter in the cavity is also radiated into the fluid passage, a microwave heating element such as a material with high dielectric loss or ferrite, which is a microwave resistor, is installed at the relevant location. If so, the load on the microwave oscillator becomes a microwave heating element in addition to the particulates, which can consume surplus energy, increasing oscillation efficiency, and supplying a fluid containing pre-heated oxygen during playback, allowing heating and temperature rise with microwaves. It promotes the oxidation combustion reaction without cooling the particulates and improves filter regeneration efficiency.

(6) A microwave oscillator that dielectrically heats and burns particulates, and a fluid supply means that introduces into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates, the fluid supply means and A microwave heating element having holes is provided in a cavity wall on a fluid passage connecting the filter, and when particulates are oxidized and burned to regenerate the filter, the microwave heating element heats the fluid supplied to the filter. With this structure, microwaves leaking into the fluid passage are absorbed and attenuated by the microwave heating element installed on the cavity wall, which not only prevents leakage to the outside of the cavity, but also heats the fluid containing oxygen with the microwave heating element. Therefore, the oxidation combustion reaction is promoted without cooling the particulates heated by microwaves, and the regeneration efficiency of the filter is improved.

[Brief explanation of drawings]

[Fig. 1] A system and a sectional view of essential parts of a filter regeneration device for an internal combustion engine in an embodiment of the present invention.

[Fig. 2] A cross-sectional view of essential parts of an internal combustion engine filter regeneration device according to an embodiment of the present invention.

[Fig. 3] Cross-sectional view showing the configuration of a conventional internal combustion engine filter regeneration device

[Explanation of symbols]

11 Engine 13,14 Filter 15,16 Cavity 19,20 Electric heater A 21 Fluid supply means 22 Electric heater B 22 Control valve A 29 Control valve B

Claims (6)

[Claims] 1. A filter for collecting particulates contained in exhaust gas, which is provided in an exhaust passage of an internal combustion engine;
a cavity that houses and holds the filter; and a heat source that heats and burns particulates accumulated in the filter; A filter regeneration device for an internal combustion engine configured to operate periodically. 2. A filter for collecting particulates contained in exhaust gas, which is provided in an exhaust passage of an internal combustion engine;
A cavity that houses and holds the filter, a heat source that heats and burns the particulates accumulated in the filter, and a fluid supply means that introduces into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. The heat source is operated periodically while the exhaust gas flow is introduced into the filter to collect particulates, and when the particulates are oxidized and burned and the filter is regenerated, the exhaust gas flow is shut off and the particulates are collected. A filter regeneration device for an internal combustion engine configured to supply fluid from a fluid supply means to the cavity in which the filter is housed. 3. A filter for collecting particulates contained in exhaust gas, which is provided in an exhaust passage of an internal combustion engine;
a cavity for storing and holding the filter; a first heat source for heating and burning particulates accumulated in the filter; and a fluid supply means for introducing into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. A second heat source is provided in the fluid passage connecting the fluid supply means and the filter, and when the particulates are oxidized and burned to regenerate the filter, the fluid supplied to the filter is controlled by the second heat source. A filter regeneration device for an internal combustion engine configured to heat. 4. The filter regeneration device for an internal combustion engine according to claim 3, wherein at least one of the two heat sources is constituted by dielectric heating means using microwaves. 5. A filter for collecting particulates contained in exhaust gas, which is provided in an exhaust passage of an internal combustion engine;
A cavity for storing and holding the filter, a microwave oscillator for dielectrically heating and burning particulates accumulated in the filter, and a fluid supply means for introducing into the cavity a fluid containing oxygen necessary for oxidizing and burning the particulates. a microwave heating element having holes is provided in a fluid passage connecting the fluid supply means and the filter, and when particulates are oxidized and burned to regenerate the filter, the microwave heating element supplies the fluid to the filter. A filter regeneration device for an internal combustion engine configured to heat a fluid that is heated. 6. The filter for an internal combustion engine according to claim 5, wherein the microwave heating element is provided on a cavity wall on a fluid passage connecting the fluid supply means and the filter.