JP2004360513A - Exhaust gas purification device - Google Patents

Abstract

Provided is an exhaust gas purifying apparatus capable of avoiding a decrease in power factor caused by a trapped amount of particulates and a component of exhaust gas.
A collecting cell for capturing particulates between electrodes disposed in a flow path of exhaust gas, a high voltage output means for supplying AC power to the electrodes, and a high voltage output means. And a plurality of inductors L1 to L6 that can be connected in parallel between the electrodes 5, the switches S1 to S6 attached to the inductors L1 to L6, the phases of AC power supplied to the electrodes 4 and 5, and There is provided an inductance control means 3 for closing any of the switches S1 to S6 and connecting any of the inductors L1 to L6 to the high voltage output means 2 and the electrode 5 so as to reduce the fluctuation of the reactance.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust gas purification device.
[0002]
[Prior art]
Diesel engine exhaust gas (combustion gas of light oil) contains, as main components, soot composed of carbonaceous material and SOF (Soluble Organic Fraction: soluble organic component) composed of a high-boiling hydrocarbon component, and contains a small amount of sulfate (mist-like component). Particulate matter (particulate matter) having a composition to which a sulfuric acid component is added.
[0003]
In order to suppress the diffusion of the particulates into the atmosphere, a filter for collecting particulates is incorporated in an engine exhaust system.
[0004]
As an example of the particulate filter, there is a filter in which a honeycomb core is formed of ceramics such as cordierite and the engine exhaust gas flows through a number of passages divided by the porous thin walls of the honeycomb core.
[0005]
In the particulate filter, one end portion of each of a number of parallel passages is sealed, and engine exhaust is guided to an unsealed one end portion of a gas passage adjacent thereto. The other end of the gas passage is closed, and the other end of the gas passage adjacent to the other end is connected to the muffler.
[0006]
That is, the particulates contained in the engine exhaust are collected by the porous thin wall, and only the exhaust passing through the porous thin wall is released to the atmosphere.
[0007]
Further, the particulates adhered to the porous thin wall are oxidized by spontaneous ignition when the operating state of the engine is shifted to a region where the exhaust gas temperature becomes high.
[0008]
However, in the case of route buses operating mainly in urban areas, the traveling speed is generally low, and there is little opportunity for the engine to operate at an exhaust temperature suitable for particulate oxidation treatment. Exceeds the oxidation treatment amount, and the porous thin wall is closed.
[0009]
Therefore, in recent years, a plasma-assisted exhaust gas purification device (gas treatment reactor) capable of oxidizing particulates even at a low exhaust gas temperature has been proposed (for example, see Patent Document 1).
[0010]
In this exhaust gas purification apparatus, an outer electrode and an inner electrode formed by piercing a stainless steel cylinder are coaxially arranged in a chamber, and a pellet made of a dielectric is filled in a gap between the two electrodes with the engine exhaust gas to be processed. So that the engine exhaust can be guided to the gap between the chamber and the outer electrode.
[0011]
That is, the particulates contained in the engine exhaust gas sent from the chamber and the external electrode to the pellet-packed layer are attached to the pellets, and only the engine exhaust gas that has passed through the pellet-packed layer is released to the atmosphere.
[0012]
Furthermore, ozone and oxygen radicals are generated by applying a high voltage to the inner and outer electrodes to generate discharge plasma to excite engine exhaust.
[0013]
Thereby, even when the exhaust gas temperature is low, the particulates attached to the pellets are ignited spontaneously and oxidized.
[0014]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2002-501813
[Problems to be solved by the invention]
In the above-described plasma-assisted exhaust gas purification apparatus, when the electric power for discharge is AC, an equivalent circuit is a circuit that applies an AC high voltage to a capacitor formed by inner and outer electrodes.
[0016]
However, since the capacitance of the above-mentioned capacitor changes depending on the amount of trapped particulates and exhaust components, the reactance of the circuit fluctuates, causing a phase shift between the voltage waveform and the current waveform, and a reduction in the power factor. is assumed.
[0017]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an exhaust gas purifying apparatus capable of avoiding a decrease in power factor due to a particulate collection amount and an exhaust gas component.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 includes a collection cell for capturing particulates between a pair of electrodes disposed in a flow path of exhaust gas, and a high voltage output for supplying AC power for discharge to both electrodes. Means, a plurality of inductors which can be connected in parallel between the high voltage output means and the electrodes, and a high voltage output means for detecting the phase of AC power supplied to both electrodes and reducing the fluctuation of reactance. Means and an inductance control means connected to the electrodes.
[0019]
The invention according to claim 2 is a collection cell that captures particulates between a pair of electrodes arranged in a flow path of exhaust gas, high voltage output means for supplying discharge AC power to both electrodes, and the high voltage output means. A variable inductor provided between the means and the electrode; and an inductance control means for detecting a phase of AC power supplied to both electrodes and adjusting the variable inductor so as to reduce a variation in reactance.
[0020]
The invention according to claim 3 is a collection cell that captures particulates between a pair of electrodes arranged in a flow path of exhaust gas, high voltage output means for supplying discharge AC power to both electrodes, and the high voltage output means. A plurality of variable inductors that can be connected in parallel between the means and the electrodes, and a variable inductor connected to the high-voltage output means and the electrodes so as to detect the phase of AC power supplied to both electrodes and reduce fluctuations in reactance And an inductance control means for adjusting the variable inductance.
[0021]
According to the first aspect of the present invention, the inductance control means for detecting the phase of the AC power supplied to both electrodes of the collection cell includes a predetermined inductance and a high voltage output means so as to reduce the reactance fluctuation. Connect to electrodes.
[0022]
According to the second aspect of the present invention, the inductance control means for detecting the phase of the AC power supplied to both electrodes of the collection cell adjusts the variable inductance so as to reduce the variation in the reactance.
[0023]
According to the third aspect of the present invention, the inductance control means for detecting the phase of the AC power supplied to both electrodes of the collection cell includes a predetermined variable inductance and a high-voltage output means for reducing the reactance fluctuation. And the electrode, and further adjusts the variable inductance.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0025]
FIG. 1 shows a first example of an embodiment of an exhaust gas purifying apparatus according to the present invention. This exhaust gas purifying apparatus comprises a collecting cell 1, high-voltage output means 2 for outputting discharge AC power, and a plurality of exhaust cells. It has inductors L1 to L6 and inductance control means 3.
[0026]
The collection cell 1 has a pair of electrodes 4 and 5 arranged in a flow path of the exhaust gas G to be purified and a dielectric 6 such as ceramics covering one electrode 4. It is formed of a conductive filter capable of collecting particulates.
[0027]
The shape of the electrodes 4 and 5 may be any of a cylindrical type, a flat plate facing type, and a lattice type.
[0028]
Examples of the conductive filter include a filter obtained by laminating fibrous metals and integrating them by sintering, a sintered body of metal powder, a filter obtained by laminating a fine metal mesh and integrating them by sintering, or a fine metal. There are, for example, a metal powder supported on a mesh by sintering, and these can collect particulates while ensuring gas permeability, and the particulates are formed on the surface of the dielectric 6. Also adheres to.
[0029]
Switches S1 to S6 are connected in series to the inductors L1 to L6, respectively. The series connection of the inductors L1 to L6 and the switches S1 to S6 is connected to the high voltage output means 2 and the electrode 5 of the collection cell 1. They are connected in parallel.
[0030]
The inductance control unit 3 detects a phase shift between an AC voltage waveform and a current waveform applied to the electrodes 4 and 5 from the high voltage output unit 2 in a state where at least one of the switches S1 to S6 is closed. After calculating the inductance required to reduce the fluctuation of the reactance at the time, the inductance is approximated (or matched) with the calculated value, and the inductance is approximated by a single circuit of the inductors L1 to L6 or a combination thereof. The switches S1 to S6 attached to the inductors L1 to L6 to be connected are closed.
[0031]
That is, when the inductances of the inductors L1 to L6 are equal, five kinds of inductance values can be obtained by opening and closing the switches S1 to S6, and when the inductances of the inductors L1 to L6 are different, the switch S1 With the combination of opening and closing of S6, up to 35 different inductance values can be obtained.
[0032]
As described above, the predetermined inductors L1 to L6 are connected to the high voltage output means 2 and the electrodes 4 and 5 so that the inductance control means 3 reduces the reactance fluctuation. A reduction in the power factor, which is a factor, can be avoided and energy efficiency can be improved.
[0033]
Therefore, when the collection amount of particulates in the collection cell 1 becomes excessive, if AC power is supplied from the high voltage output means 2 to the electrodes 4 and 5 to generate discharge plasma, ozone and oxygen radicals cause In addition, the particulates can be reliably oxidized.
[0034]
FIG. 2 shows a second example of the embodiment of the exhaust gas purification apparatus of the present invention. This exhaust gas purification apparatus includes a collection cell 1, a high voltage output means 2, a variable inductor L7, and an inductance control means 7. The collection cell 1 and the high voltage output means 2 have the same structure as that of FIG.
[0035]
The inductance control means 7 detects a phase shift between the AC voltage waveform and the current waveform applied to the electrodes 4 and 5 from the high voltage output means 2 and calculates the inductance required to reduce the fluctuation of the reactance at that time. In addition, the variable inductor L7 is adjusted so as to obtain an inductance that approximates (or matches) the calculated value.
[0036]
That is, an inductance value in a range according to the design conditions of the variable inductor L7 is obtained.
[0037]
In this manner, the variable inductor L7 is adjusted so that the inductance control means 7 reduces the variation in reactance. Therefore, a decrease in the power factor due to the amount of trapped particulates and exhaust components can be avoided, and the energy efficiency can be reduced. Improvement is achieved.
[0038]
Therefore, when the amount of particulates collected by the collection cell 1 becomes excessive, if AC power is supplied from the high voltage output means 2 to the electrodes 4 and 5 to generate discharge plasma, ozone and oxidized radicals cause In addition, the particulates can be reliably oxidized.
[0039]
FIG. 3 shows a third embodiment of the exhaust gas purifying apparatus according to the present invention. This exhaust gas purifying apparatus comprises a collecting cell 1, high voltage output means 2, variable inductors L8 and L9, and inductance control means. 8, the collection cell 1 and the high voltage output means 2 have the same structure as that of FIG.
[0040]
Switches S8 and S9 are connected in series to the variable inductors L8 and L9, respectively. The series connection of the variable inductors L8 and L9 and the switches S8 and S9 forms the high voltage output means 2 and the electrode 5 of the collection cell 1. Are connected in parallel.
[0041]
The inductance control means 8 detects a phase shift between the AC voltage waveform and the current waveform applied to the electrodes 4 and 5 from the high voltage output means 2 in a state where at least one of the switches S8 and S9 is closed. After calculating the inductance required to reduce the fluctuation of the reactance at the time, the inductance that approximates (or matches) the calculated value can be obtained by a single variable inductor L8 or L9 or a combination thereof. The switches S8 and S9 attached to the variable inductors L8 and L9 to be connected are closed and the variable inductors L8 and L9 are adjusted.
[0042]
That is, an inductance value in a range according to the design conditions of the variable inductors L8 and L9 alone or a combination thereof is obtained.
[0043]
As described above, since the variable inductors L8 and L9 are adjusted so that the inductance control means 8 reduces the reactance fluctuation, a decrease in the power factor due to the amount of trapped particulates and components of the exhaust gas can be avoided, and the energy can be reduced. The efficiency is improved.
[0044]
Therefore, when the collection amount of particulates in the collection cell 1 becomes excessive, if AC power is supplied from the high voltage output means 2 to the electrodes 4 and 5 to generate discharge plasma, ozone and oxygen radicals cause In addition, the particulates can be reliably oxidized.
[0045]
It should be noted that the exhaust gas purifying apparatus of the present invention is not limited to the above-described embodiment, but may be modified without departing from the scope of the present invention.
[0046]
【The invention's effect】
As described above, according to the exhaust gas purification apparatus of the present invention, the following excellent effects can be obtained.
[0047]
(1) According to the first aspect of the present invention, based on the phase of the AC power, the inductance control means connects a predetermined inductor to the high-voltage output means and the electrode to reduce the reactance fluctuation. It is possible to avoid a decrease in the power factor due to a component of the exhaust gas, thereby improving energy efficiency.
[0048]
(2) According to the second aspect of the present invention, based on the phase of the AC power, the inductance control means adjusts the variable inductor to reduce the reactance fluctuation. The rate can be prevented from lowering, and the energy efficiency is improved.
[0049]
(3) In the invention according to claim 3, the inductance control means connects a predetermined variable inductor to the high-voltage output means and the electrode based on the phase of the AC power, and adjusts the variable inductor to reduce the reactance fluctuation. Therefore, it is possible to avoid a decrease in the power factor due to the amount of trapped particulates and the components of the exhaust gas, thereby improving the energy efficiency.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a first example of an embodiment of an exhaust gas purification device of the present invention.
FIG. 2 is a conceptual diagram showing a second example of the embodiment of the exhaust emission control device of the present invention.
FIG. 3 is a conceptual diagram showing a third example of the embodiment of the exhaust emission control device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Collection cell 2 High voltage output means 3,7,8 Inductance control means 4,5 Electrodes L1-L6 Inductors L7-L9 Variable inductor G Exhaust

Claims (3)

A collection cell that captures particulates between a pair of electrodes arranged in a flow path of exhaust gas, a high-voltage output unit that supplies AC power for discharge to both electrodes, and a parallel connection between the high-voltage output unit and the electrodes A plurality of inductors, and an inductance control means for detecting the phase of AC power supplied to both electrodes and connecting the inductors to the high voltage output means and the electrodes so as to reduce the variation in reactance. Exhaust gas purifier characterized. A collection cell that captures particulates between a pair of electrodes arranged in a flow path of exhaust gas, a high-voltage output unit that supplies AC power for discharge to both electrodes, and a variable unit that is provided between the high-voltage output unit and the electrodes. An exhaust gas purification apparatus comprising: an inductor; and an inductance control unit that detects a phase of AC power supplied to both electrodes and adjusts a variable inductor so as to reduce a variation in reactance. A collection cell that captures particulates between a pair of electrodes arranged in a flow path of exhaust gas, a high-voltage output unit that supplies AC power for discharge to both electrodes, and a parallel connection between the high-voltage output unit and the electrodes And a plurality of variable inductors, and an inductance control for adjusting the variable inductance by connecting the variable inductors to the high-voltage output means and the electrodes so as to detect the phase of AC power supplied to both electrodes and reduce the fluctuation of reactance. Exhaust gas purifying device comprising:

Images