Method and apparatus for using free radicals to reduce pollutants in the exhaust gases from the combustion of fuel
First Claim
1. An apparatus for reducing at least one pollutant in an exhaust gas stream containing exhaust gas formed from the combustion of fuel in an engine, the apparatus comprising:
- a catalytic convertor, having an inlet and an outlet, wherein the catalytic convertor is positioned such that at least a portion of the exhaust gas stream from the engine passes through the catalytic convertor;
a corona discharge device for producing a corona discharge in the exhaust gas, the corona discharge device comprising at least one first electrode, at least one second electrode positioned a distance from the first electrode and a dielectric material positioned between the first electrode and the second electrode; and
a high frequency power supply having an operational frequency of at least about 1,000 Hz adapted to provide electrical power to the corona discharge device,wherein at least a portion of the exhaust gas stream is exposed to the corona discharge to produce radicals from gaseous species in the exhaust gas stream, and the radicals are introduced into the exhaust gas stream at a point upstream of or at the catalytic convertor.
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Accused Products
Abstract
The invention is directed to an apparatus and a method for the reduction of pollutants in the exhaust stream of a combustion engine. Radicals are produced using a corona discharge in the combustion gas stream of the engine, either in the precombustion gas stream or from water in the exhaust gas. When the radicals are produced from the exhaust gas stream, the radicals may be produced using a corona discharge placed directly in the exhaust stream leading to the catalytic convertor, or a portion of the exhaust stream may be diverted to a remote corona discharge radical generator. The corona discharge in the generator produces radicals in the diverted exhaust gas, and the exhaust gas containing radicals is then conveyed to the exhaust gas stream at a point upstream of the catalytic convertor.
74 Citations
73 Claims
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1. An apparatus for reducing at least one pollutant in an exhaust gas stream containing exhaust gas formed from the combustion of fuel in an engine, the apparatus comprising:
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a catalytic convertor, having an inlet and an outlet, wherein the catalytic convertor is positioned such that at least a portion of the exhaust gas stream from the engine passes through the catalytic convertor; a corona discharge device for producing a corona discharge in the exhaust gas, the corona discharge device comprising at least one first electrode, at least one second electrode positioned a distance from the first electrode and a dielectric material positioned between the first electrode and the second electrode; and a high frequency power supply having an operational frequency of at least about 1,000 Hz adapted to provide electrical power to the corona discharge device, wherein at least a portion of the exhaust gas stream is exposed to the corona discharge to produce radicals from gaseous species in the exhaust gas stream, and the radicals are introduced into the exhaust gas stream at a point upstream of or at the catalytic convertor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. An apparatus for reducing at least one pollutant in an exhaust gas stream containing exhaust gas formed from the combustion of fuel in an engine having a combustion gas stream, which comprises a precombustion gas stream and the exhaust gas stream, the apparatus comprising:
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a catalytic convertor, having an inlet and an outlet, where the catalytic convertor is positioned such that at least a portion of the exhaust gas stream from the engine passes through the catalytic convertor; a corona discharge device for producing radicals in the combustion gas stream of the engine, the corona discharge device comprising at least one first electrode, at least one second electrode positioned a distance from the first electrode, and a dielectric material positioned between the first electrode and the second electrode; and a high frequency power supply having an operational frequency of at least about 1,000 Hz adapted to provide electrical power to the corona discharge device, wherein at least a portion of the combustion gas stream is exposed to the corona discharge to produce radicals from gaseous species in the combustion gas stream, wherein the radicals are introduced into the combustion gas stream upstream of or at the catalytic convertor. - View Dependent Claims (28, 29, 30)
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31. An apparatus for reducing at least one pollutant in an exhaust gas stream containing exhaust gas formed from the combustion of fuel in an engine, the apparatus comprising:
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a catalytic convertor, having an inlet and an outlet, wherein the catalytic convertor is positioned such that at least a portion of the exhaust gas stream from the engine passes through the catalytic convertor; a corona discharge device for producing a corona discharge in the exhaust gas stream, such that radicals are produced from gaseous species in the exhaust gas stream, and the radicals are introduced into the exhaust gas stream at a point upstream of or at the inlet of the catalytic convertor; an exhaust pipe attached to the inlet of the catalytic convertor, such that at least a portion of the exhaust gas stream passes through the exhaust pipe to and through the catalytic convertor, the exhaust pipe comprising a fitting configured for attaching the corona discharge device to the exhaust pipe and allowing exhaust gas to enter into and exit from the corona discharge device; wherein the corona discharge device comprises; a first end, configured for attachment to the fitting, and to allow exhaust gas from the exhaust pipe to enter into and exit from the corona discharge device, a second end, configured to prevent exhaust gas from leaking from the corona discharge device, a generally cylindrical outer electrode, electrically and mechanically connected to the first end, an inner electrode, mounted concentric with, and partially surrounded by the outer electrode, and a dielectric, mounted concentric with, and positioned between the inner and outer electrodes, forming an air gap between the electrodes, the dielectric having a diameter that defines the corona discharge device diameter, wherein the inner electrode has a length that is greater than that of the outer electrode to provide a corona region in the air gap near the first end and a ullage volume in the air gap near the second end. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39)
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40. A method for the reduction of at least one pollutant in an exhaust gas stream containing exhaust gas formed from the combustion of fuel in an engine having an exhaust pipe attached to an inlet of a catalytic convertor, the method comprising:
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passing the exhaust gas stream through the exhaust pipe and the catalytic convertor; forming radicals in at least a portion of the exhaust gas stream by generating a corona discharge therein, produced by a corona discharge device, which comprises at least one first electrode, at least one second electrode positioned a distance from the first electrode, and a dielectric material positioned between the first electrode and the second electrode, providing electrical power to the corona discharge device with a high frequency power supply having an operational frequency of at least about 1,000 Hz; and introducing the radicals into the exhaust gas stream upstream of or at the catalytic convertor. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57)
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58. A method for the reduction of at least one pollutant in an exhaust gas stream containing exhaust gas formed from the combustion of fuel in an engine having a combustion gas stream, which comprises a precombustion gas stream and an exhaust gas stream, and an exhaust pipe attached to an inlet of a catalytic convertor, the method comprising:
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passing the exhaust gas stream through the exhaust pipe and the catalytic convertor; forming radicals in at least a portion of the combustion gas stream by generating a corona discharge therein, produced by a corona discharge device, which comprises at least one first electrode, at least one second electrode positioned a distance from the first electrode, and a dielectric material positioned between the first electrode and the second electrode; providing electrical power to the corona discharge device with a high frequency power supply having an operational frequency of at least about 1,000 Hz; and introducing the radicals into the combustion gas stream upstream of or at the catalytic convertor. - View Dependent Claims (59)
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60. A method for improving the life and performance of an oxygen sensor of an engine having a combustion gas stream, which comprises a precombustion gas stream and an exhaust gas stream, wherein the oxygen sensor is positioned in the exhaust gas stream upstream of a catalytic convertor having an inlet and an outlet, the method comprising:
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producing radicals in at least a portion of the combustion gas stream by generating a corona discharge therein, produced by a corona discharge device, which comprises at least one first electrode, at least one second electrode positioned a distance from the first electrode, and a dielectric material positioned between the first electrode and the second electrode; providing electrical power to the corona discharge device with a high frequency power supply having an operational frequency of at least about 1,000 Hz; and introducing the radicals into the combustion gas stream upstream of the oxygen sensor to remove or prevent the deposition of poisoning agents onto the oxygen sensor. - View Dependent Claims (61, 62, 63, 64)
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65. A compact corona discharge device for forming a corona discharge in exhaust gas in an exhaust system of an internal combustion engine to reduce at least one pollutant, the compact corona discharge device comprising:
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a first end, configured for attachment to a fitting in the exhaust system to allow exhaust gas from the exhaust system to enter into and exit from the corona discharge device, a second end, configured to prevent exhaust gas from leaking from the corona discharge device, a generally cylindrical outer electrode, electrically and mechanically connected to the first end, an inner electrode, mounted concentric with, and partially surrounded by the outer electrode, and a dielectric insulator, mounted concentric with, and positioned between the inner and outer electrodes, forming an air gap between the electrodes, the dielectric insulator having a diameter that defines the corona discharge device diameter, wherein the inner electrode has a length that is greater than that of the outer electrode to provide a corona region in the air gap near the first end and a ullage volume in the air gap near the second end.
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66. A method for the reduction of at least one pollutant in an exhaust gas stream containing exhaust gas formed from the combustion of fuel in an engine having a combustion gas stream, which comprises a precombustion gas stream and the exhaust gas stream, and an exhaust pipe attached to an inlet of a catalytic convertor, the method comprising:
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passing the exhaust gas stream through the exhaust pipe and the catalytic convertor; forming radicals in the combustion gas stream by generating a corona discharge in at least a portion thereof;
wherein the radicals produced by the corona discharge device, which comprises at least one first electrode, at least one second electrode positioned a distance from the first electrode, and a dielectric material positioned between the first electrode and the second electrode;providing electrical power to the corona discharge device with a high frequency power supply having an operational frequency of or at least about 1,000 Hz; introducing the radicals into the combustion gas stream upstream of or at the catalytic convertor; and reacting the radicals or an oxidizing species with at least one pollutant in at least one of the catalytic convertor or the exhaust gas stream upstream of the catalytic convertor, wherein the oxidizing species is produced by reaction of the radicals with gaseous species in the combustion gas stream. - View Dependent Claims (67)
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68. An apparatus for reducing at least one pollutant in an exhaust gas stream containing exhaust gas formed from the combustion of fuel in an engine, the apparatus comprising:
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a catalytic convertor, having an inlet and an outlet, wherein the catalytic convertor is positioned such that at least a portion of the exhaust gas stream from the engine passes through the catalytic convertor; a corona discharge device for producing a corona discharge in the exhaust gas; and a high frequency power supply having an operational frequency of at least about 1,000 Hz adapted to provide electrical power to the corona discharge device, wherein the corona discharge device comprises; a first, inner electrode, having a diameter of from about 0.1 to about 0.3 cm, a second, outer electrode, having an inner diameter of about 1 to about 2 cm and a length of about 1.5 to 3 cm, positioned a distance from the first electrode, and a dielectric material, having a thickness of from about 1 to about 3 mm positioned between the first electrode and the second electrode, and the corona discharge is positioned within at least a portion of the exhaust gas to produce radicals from gaseous species in the exhaust gas, and the radicals are introduced into the exhaust gas stream at a point upstream of or at the inlet of the catalytic convertor. - View Dependent Claims (69)
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70. A method for the reduction of at least one pollutant in an exhaust gas stream containing exhaust gas formed from the combustion of fuel in an engine having an exhaust pipe attached to an inlet of a catalytic convertor, the method comprising:
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passing the exhaust gas stream through the exhaust pipe and the catalytic convertor; forming radicals in at least a portion of the exhaust gas stream by generating a corona discharge therein, produced by a corona discharge device, which comprises a first electrode, a second electrode positioned a distance from the first electrode, and a dielectric material positioned between the first electrode and the second electrode; providing electrical power to the corona discharge device with a high frequency power supply having an operational frequency of at least about 1,000 Hz; introducing the radicals into the exhaust gas stream upstream of or at the catalytic convertor; and removing at least a portion of at least one pollutant in the exhaust gas stream by reaction of the pollutant with the radicals in a catalytic reaction that regenerates at least a portion of the radicals. - View Dependent Claims (71, 72, 73)
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Specification