Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/30—Arrangements for supply of additional air
  • F01N3/34—Arrangements for supply of additional air using air conduits or jet air pumps, e.g. near the engine exhaust port
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/26—Construction of thermal reactors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/30—Arrangements for supply of additional air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J15/00—Arrangements of devices for treating smoke or fumes
  • F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
  • F23J7/00—Arrangement of devices for supplying chemicals to fire
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
  • F01N2240/20—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a flow director or deflector
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2260/00—Exhaust treating devices having provisions not otherwise provided for
  • F01N2260/14—Exhaust treating devices having provisions not otherwise provided for for modifying or adapting flow area or back-pressure
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies

Definitions

• the present invention relates generally to the purification of exhaust gases from various types of combustion apparatus, such as engines, furnaces, heating boilers etc. More specifically, the invention concerns a device and a method for purifying such exhaust gases.
• Combustion is a chemical reaction in which a combustible substance combines with oxygen to form one or more combustion products.
• CO carbon monoxide
• NO x nitric oxides
• HC unburnt hydrocarbon compounds
• C0 2 carbon dioxide
• the device which is arranged after the engine and through which the exhaust gases flow, mixes secondary air with the exhaust gases and then ignites the exhaust-gas-air mixture by means of a spark igniter.
• exhaust gas substances such as carbon monoxide, hydrocarbons and particles are oxidised.
• This type of device is difficult to control and is not capable of purifying the exhaust gases from a car engine in compliance with today's stringent requirements.
• a further device for aftertreatment of exhaust gases is the catalytic converter, which is known from e.g. WO 93/24745 and which, by catalytic oxidisation, reduces the contents of some combustion products.
• the converter comprises a vessel through which exhaust gases flow and which contains a catalytic material having a large surface area.
• the cataly- tic converter requires a high working temperature, normally at least 900 °C, that it only functions at an exact stoichiometric mixing ratio, that it is expensive and not very lasting, that it is sensitive to certain substances, such as lead, that may be present in the fuel, and that it can be used only for purification of emissions from gasoline engines.
• One object of the present invention is to overcome, wholly or partly, the above-discussed problems of prior art, i.e. to provide a device and a method for purifying exhaust gases from combustion apparatus, both the device and the method resulting in purification of the exhaust gases in accordance with stringent environmental requirements, i.e. accomplishing a considerable reduction of the contents of one or more of: carbon dioxide, carbon monoxide, nitrogen oxides and hydrocarbons in the exhaust gases.
• the construction of the device should be as simple and robust as possible.
• a further object of the invention is to provide a device and a method which are capable of purifying the exhaust gases independently of which type of fuel is used in the combustion apparatus.
• Fig. 1 is a schematic view of an inventive device.
• Fig. 2 illustrates an inventive device that is used in a first experiment for purifying the emissions from a gasoline engine.
• Fig. 3 illustrates an inventive device that is used in a second experiment for purifying the emissions from a diesel engine. Description of the Preferred Embodiments
• Fig. 1 is a schematic view of an embodiment of an inventive purifying device 1 which is connected to a combustion apparatus 2, such as an internal combustion engine.
• the purifying device 1 comprises a closed vessel or collecting chamber 3, which, through a first inlet 4, is in fluid communication with the outlet 5 of the com- bustion apparatus 2.
• An outlet 6 of the collecting chamber 3 is in fluid communication with a negative pressure generating means 7, such as a vacuum pump or a fan.
• the negative pressure generating means 7 is in turn connected by an exhaust pipe 8 to a silencer 9.
• a second inlet 10 of the collecting chamber 3 is in fluid communication with a means 11 for supplying additional oxidising agent. During operation, a negative pressure is established in the collecting chamber 3 with the aid of the negative pressure means 7.
• the negative pressure causes hot com- bustion gases to be sucked out of the combustion apparatus 2 and into the collecting chamber 3, which preferably is arranged in the immediate vicinity of the combustion apparatus 2.
• the negative pressure also results in additional oxidising agent, such as air, being suckable into the collecting chamber 3 from the supply means 11.
• the collecting chamber 3 has an internal, turbulence-producing profile 12 which generates an efficient mixture of the combustion gases expanding in the chamber 3 and the added oxidising agent.
• the gas mixture is then sucked into the negative pressure means 7 and is ejected thereby into the exhaust pipe 8. All combustion gases thus leave the collecting chamber 3 through the negative pressure means 7.
• the negative pressure in the collecting chamber 3 preferably is in the range of 0.25-0.8 atm absolute pressure (25-80 kPa) . It was noted that the purifying effect is enhanced in the lower part of the pressure range. To a certain degree, the aimed-at purification was obtained also slightly above the negative pressure of 0.8 atm (80 kPa) .
• the negative pressure established in the collecting chamber assists in the emptying of the combustion chamber of the engine during the exhaust stroke, whereby the output power of the engine increases since a greater amount of fuel-air mixture can be sucked into the combustion chamber during the subsequent intake stroke.
• the pressure prevailing in the collecting chamber should be lower than the ambient atmospheric pressure as well as the pressure in the com- bustion apparatus when emitting the combustion gases to the purifying device.
• the negative pressure should not be so large as to unfavourably affect the combustion in the apparatus.
• an inventive purifying device was connected to a combustion apparatus in the form of a gasoline engine, more specifically a 1974 VOLVO B20 having a volume of about 2,000 cm 3 .
• the engine was dismounted from a vehicle which before the tests had a mileage of around 350,000 kilometres. No adjustments of the engine were made before the tests, but the engine was mounted together with gear box, starting motor, battery and fuel tank in a test bench. During the experiment, the engine was run without braking at 1,000 rpm.
• the collecting chamber 3 was cylindrical and had a diameter of 200 mm and a length of 400 mm. The volume of the chamber 3 thus was 12.6 dm 3 .
• a first inlet 4 of the chamber 3 was connected to a 90° pipe bend 13, whose dia- meter was 130 mm.
• the pipe bend 13 had a flange 14 which during the experiment was connected to the exhaust manifold (not shown) of the engine.
• the outlet 6 of the collecting chamber 3 was connected, by means of a pipe 15 having a diameter of 50 mm and a length of 100 mm, to a negative pressure generating means 7 in the form of a standard-type turbocharger (VOLVO) , which during the experiment was constantly operated by compressed air (0.8 MPa; 8 bar) for the purpose of generating a negative pressure in the collecting cham- ber 3.
• VOLVO standard-type turbocharger
• This negative pressure was measured during the experiment to be about 0.7 atm (70 kPa) absolute pressure by means of an air pressure gauge (not shown) mounted on the collecting chamber 3.
• a second inlet 10 of the collecting chamber was con- nected to an air supply means in the form of a manually operable stopcock 11.
• a second air supply means also in the form of a stopcock 11', was connected to the pipe bend 13.
• This oxidising agent consisted either of air only or of air containing about 2 ppm ozone.
• the volume flow rate of oxidising agent was measured to be about 2.8% of the volume flow rate of exhaust gases from the engine.
• An exhaust pipe 8 having a diameter of 50 mm and a length of 800 mm was connected to the turbocharger 7 for releasing the purified exhaust gases.
• the temperature of the exhaust gases was measured to be about 100 °C, and therefore the temperature decrease over the collecting chamber 3 will probably have amounted to about 800-1000°C.
• a conventional measuring apparatus Hackman & Brum MG and URAT P
• probes (not shown) being arranged about 200 mm from the far end of the exhaust pipe 8.
• Table 1 Contents of substances in exhaust gases from a gasoline engine run at 1000 rpm without braking.
• an inventive purifying device was connected to a combustion appara- tus in the form of a diesel engine, more specifically a 1977 Ford 504 having a volume of about 2,300 cm 3 .
• the motor had a mileage of around 300,000 kilometres. No adjustments of the engine were made before the tests, but it was mounted together with gear box, starting motor, battery and fuel tank in a test bench.
• a brake system was mounted on the output shaft of the gear box, and during the experiment, the motor was run either at 6,000 rpm with full braking or at 1,000 rpm without braking.
• the collecting chamber 3 was cylindrical and had a diameter of 110 mm and a length of 920 mm.
• the volume of the chamber 3 was about 8.7 dm 3 .
• a first inlet 4 of the chamber 3 was connected by a tube 13 having a flange 14 to the exhaust manifold of the engine.
• the outlet 6 of the collecting chamber 3 was connected directly to a negative pressure generating means 7 in the form of a fan (Nederman, Model N16) having a capacity of 0.44 m 3 /s.
• a second inlet 10 of the col- lecting chamber 3 was connected to an air supply means in the form of a manually operable stopcock 11.
• the stopcock 11 was either fully open, whereby additional oxidising agent in the form of air was supplied to the chamber 3 by self-suction, or fully closed such that no oxidising agent was supplied to the chamber 3.
• the volume flow rate of air was measured to be about 2.8% of the volume flow rate of exhaust gases from the engine.
• An exhaust pipe 8 having a diameter of 60 mm and a length of 1000 mm was connected to the fan 7 to release the purified exhaust gases. After the fan 7, the temperature of the exhaust gases was measured to be about 100 °C, and therefore the temperature decrease over the collecting chamber 3 will probably have amounted to about 800-1000 °C.
• the same measuring apparatus as in Experiment 1 was used to quantify the purification degree. Reference measurements were carried out in the same manner as in Experiment 1.
• Tables 2a-2b The results of the experiment are shown in the Tables 2a-2b below, Table 2a concerning a first operat- ing state at 6000 rpm with full braking, and Table 2b concerning a second operating state at 1000 rpm without braking.
• TEST I relates to measurements in which additional air is supplied through the stopcock 11 and TEST II relates to measurements with no supply of additional air.
• Table 2a Contents of substances in exhaust gases from a diesel engine that was run at 6000 rpm with full braking.
• Table 2b Contents of substances in exhaust gases from a diesel engine that was run at 1000 rpm without braking.
• the model predicts that the ratio of engine volume to volume of the collecting chamber should be greater than about 1:1, preferably in the range from 1:1 to 1:10, and most preferred about 1:3.
• a large volume of the collecting chamber would certainly result in satisfactory purification but at the same time cause a reduced output power from the engine.
• a smaller volume of the collecting chamber will, according to the model, probably result in inferior purification.
• 1:3 is considered the optimum ratio.
• the model predicts that the combustion gases flowing into the collecting chamber should have a temperature of at least 500°C for accomplishing satisfactory purification.
• the purification efficiency of the device will probably be better the closer to the engine it is arranged and the hotter the entering combustion gases, and therefore the purifying device should preferably be arranged in the immediate vicinity of the combustion.
• the purifying device can be supplemented with a control unit which, for instance in dependence on the speed of the engine, gas flow rates and temperatures, controls the negative pressure means and the supply means .
• the inventive device can be used as an auxiliary device on existing combustion apparatus for the purpose of improving the degree of purification of the exhaust gases. It may also be. designed as an integrated part of newly manufactured combustion apparatus.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Exhaust Gas After Treatment (AREA)
• Treating Waste Gases (AREA)

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• 1998
  • 1998-02-25 WO PCT/SE1998/000335 patent/WO1998037317A1/en not_active Ceased
  • 1998-02-25 EP EP98907314A patent/EP1012453A1/de not_active Withdrawn
  • 1998-02-25 AU AU63155/98A patent/AU716505B2/en not_active Ceased

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