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
  • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
  • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
  • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
  • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic 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
  • F01N13/00—Exhaust or silencing apparatus characterised by constructional features
  • F01N13/011—Exhaust or silencing apparatus characterised by constructional features having two or more purifying devices arranged in parallel
  • F01N13/017—Exhaust or silencing apparatus characterised by constructional features having two or more purifying devices arranged in parallel the purifying devices are arranged in a single housing
• • 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
  • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
  • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
  • F01N3/0214—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters with filters comprising movable parts, e.g. rotating filters
• • 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
  • F01N2250/00—Combinations of different methods of purification
  • F01N2250/02—Combinations of different methods of purification filtering and catalytic conversion
• • 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
  • F01N2410/00—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
  • F01N2410/03—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device in case of low temperature
• • 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
  • F01N3/18—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 methods of operation; Control
  • F01N3/20—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 methods of operation; Control specially adapted for catalytic conversion
  • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S55/00—Gas separation
  • Y10S55/10—Residue burned
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S55/00—Gas separation
  • Y10S55/30—Exhaust treatment

Definitions

• the present invention relates generally to the field of particle filters and more particularly to an exhaust gas filtration device for a diesel engine.
• the present invention relates to a device for filtering exhaust gases for a diesel engine further comprising a means for filtering said gases with variable capacity, in which is arranged a means of catalysis associated or not with a post injection of diesel and an exhaust gas recirculation system.
• catalytic converters or catalysts generally consisting of a stainless steel casing, of an insulator. and a honeycomb support impregnated with precious metals such as platinum or rhodium.
• an oxidation catalysis means allowing the transformation of nitrogen monoxide NO, contained in the exhaust gases, into nitrogen dioxide N0 2 from 250 ° C.
• This technique called “Continuous Regenerating Trap” (CRT)
• CRT Continuous Regenerating Trap
• This means consists of a catalytic support on which is fixed the catalyst, which is generally a precious metal such as platinum or rhodium.
• the NO 2 produced by the action of the latter has the property of oxidizing the carbon particles from 250 ° C.
• the proper functioning of the filter depends on the average temperature reached and the ratio of particles emitted relative to the NO formed.
• this CRT system requires regular regeneration, which limits the pressure drop of the filter by eliminating the risk of uncontrolled and exothermic regeneration.
• a first drawback of these techniques is the prohibitive cost of the additives used associated with the fact that it is necessary to provide a complementary additivation device.
• the objective of the present invention is to provide a method of filtering exhaust gases (in particular from diesel engines) which will remedy the drawbacks of the various existing techniques, by optimizing the filtration of exhaust gases.
• exhaust gases in particular from diesel engines
• the objective of the present invention is to provide a method of filtering exhaust gases (in particular from diesel engines) which will remedy the drawbacks of the various existing techniques, by optimizing the filtration of exhaust gases.
• diesel engines in particular in terms of regeneration of the filtration means, so as to provide a satisfactory solution to the problem of clogging of the filtration means with carbon particles.
• Another objective of the invention is to provide an exhaust gas filtration process incorporating regular, efficient and continuous regeneration, so that this avoids all Ae of accumulation of particles in the filtration means and therefore any risk of uncontrolled regeneration.
• Yet another objective of the invention is to provide a method of filtering exhaust gases in which the integrated regeneration does not result in significant overconsumption of fuel and more generally, does not entail any additional financial cost for the user.
• Yet another objective of the invention is to provide a method of filtering exhaust gases in which the integrated regeneration does not affect the performance of the engine, in particular by pressure losses, due to the back pressure exerted by the exhaust gas on the engine, due to clogging of the filtration device.
• Another objective of the invention is to provide a filtration device making it possible to implement the filtration process according to the invention.
• the present invention which firstly relates to a method of filtering exhaust gases e.g. emitted by a diesel engine.
• This exhaust gas filtration process in which all or part of the particles contained in said exhaust gases, are retained on filtration means and are burned by the action of a combustion catalyst.
• This process essentially consists in obstructing at least part of the filtration means as soon as the temperature ⁇ g of the exhaust gases to be filtered becomes less than or equal to a threshold temperature ⁇ s, so as to limit, or even avoid, the cooling of the part.
• a filtration means consisting for example of at least two cartridges arranged in an envelope, one of the two cartridges being switched off each time the engine is running without load or at idle to maintain in the insulated and flowless cartridge a temperature sufficient to cause a significant continuous regeneration speed each time the engine is again operated with hot exhaust gases.
• Each cartridge is preferably in turn switched off so that it regenerates continuously.
• the obstruction of part of the filtration means consists in preventing the circulation of the exhaust gases in at least 30%, preferably in at least 50% and more prefer! Still in 50 to 75% of the filtration means, this percentage expressing a percentage by volume.
• ⁇ s 250 ° C or 300 ° C.
• the filtration means consist of at least two - preferably at least three - filter cartridges, each equipped with a shutter, two of the three cartridges which preferably comprise the filtration means the obstinate part of the filtration means when ⁇ g ⁇ s.
• the invention relates to an exhaust gas filtration device comprising at least one means of catalysis, means for filtering said exhaust gases, arranged in a reaction enclosure in the path of the flow. exhaust gases produced by an engine, said device being characterized in that the filtration means is constituted by at least two assemblies each comprising a catalyst support attached to a filter cartridge fitted with a flow obstruction means.
• the device comprises a means for recirculating the exhaust gases at the intake of the engine, the operation of which is associated with cutting off. of the flow in one or more cartridges each time the engine is not accelerated, so that the increase in back pressure generated automatically opens a valve which allows this recirculation of the exhaust gases.
• each of the filter cartridges has a flow obstruction means, arranged upstream or downstream, controlled by an electronic computer which will take into account all the engine operating conditions, so as to isolate at least one cartridge each time the accelerator position is at zero (not accelerated).
• the filtration means consists of at least three cartridges with a means of obstructing the flow rate on each of them, controlled by an electronic computer which will take into account all the engine operating conditions, so as to isolate in turn at least two cartridges when the engine is not accelerated, and to isolate the cartridge which filters the gases in the non-accelerated position, each time the engine is accelerated.
• the flow obstruction means arranged on each filter cartridge include a calibrated orifice of small size to maintain a very low flow.
• the device comprises a system for post-injection of diesel into the exhaust gases, by means of a sprayer, preferably upstream of the filtration device and of the catalysts, controlled by an electronic computer which will take into account account for all engine operating conditions, this diesel post-injection system being possibly associated with an exhaust gas recirculation system.
• the injected diesel may be appropriate for the injected diesel to contain an organometallic as a combustion catalyst supplied or not supplied from a specific tank.
• the device may use the use of known organometallic additives which will be injected by the post injection system in place of diesel.
• the filtration means consists of a set of at least two filtering units each equipped with an obstruction means controlled by a computer which will take into account the engine operating conditions.
• each of said filtering units will include an obstruction means so that they can be switched off in turn.
• the obstruction means for each of the cartridges used will be disposed downstream of the filtration unit.
• the obstruction means can also be incorporated upstream of the filtration unit and of the associated catalyst.
• said filtering units will each integrate upstream a catalyst wafer preferably on a metal support.
• the catalyst is a conventional oxidation catalyst based on platinum so as to obtain total oxidation of the hydrocarbons and of the CO.
• the filtration device comprises a system allowing the recycling of the exhaust gases each time the filtration capacity will be reduced, thus taking advantage of the increase in the back pressure caused by this restriction for direct a portion of the unfiltered exhaust gas into the intake duct through a non-return valve.
• the filtration device comprises more than three cartridges and a sufficient number so that for full load operating conditions one of the cartridges is isolated, this cartridge being reserved for the filtration of gases at partial load or in slow motion.
• the objective being to maintain at high temperature, the filtering medium and the catalyst of each of the cartridges used at full load.
• the cartridge used at idle will be swapped with one of the others when a start of clogging is detected.
• Figure 1 shows a general view of the system comprising the filtration device with two cartridges, each having upstream an oxidation catalyst on a metal support and downstream a valve controlled to obstruct completely when necessary the flow of gases to be filtered.
• the filtration device being associated with an exhaust gas recycling system with its non-return valve.
• FIG. 2 represents a general view of the filtration device comprising a catalyst independent of the filtering units associated with an obstruction system arranged upstream.
• FIG. 3 represents a general view of the filtration device which incorporates a diesel injection system.
• Figure 4 shows a variant of the filtering device incorporating three filter cartridges.
• FIG. 5 represents a general schematic view of the filtration device with all the variants incorporated in the engine environment.
• FIG. 1 The system which allows the implementation of the filtration device according to the invention is shown in detail in Figure 1, according to a preferred embodiment.
• various mechanical elements of the vehicle collaborate, which may or may not be part of the filtration device and which contribute to regeneration.
• the exhaust gases at the outlet of the engine are introduced into the device through the pipe 1, then are directed towards each catalyst wafer on a metallic support 2, to be filtered on the two filter cartridges 3, these cartridges will preferably be made of silicon carbide, but may also consist of a leaving filter media in cordierite or other ceramic materials. They will be placed inside an enclosure 4 and isolated from the latter by means of an insulator 6, so as not to be cooled by the ambient air.
• Valves 5 will be arranged at the outlet of these filter cartridges so as to be able to completely isolate each cartridge and completely obstruct the outlet channel. These valves will be controlled by pneumatic cylinders 7, the exhaust gases then being directed towards the outlet 8.
• the device will operate as follows, each time the accelerator position returns to the zero position (not accelerated), a position detector not described will send the information to a computer, which will alternately control each cylinder to obstruct completely one of the two cartridges and use only one for these particular operating conditions.
• the filter media of the cartridge obstructed by the valve will thus maintain the high temperature it had reached during the last acceleration, the valve will not be erased to restart it until the engine is again used, so again at high exhaust gas temperatures.
• it will be the same cartridge which will be obstructed for a time between 5 and 10 minutes and alternatively, another possibility will be to measure the back pressure at idle on the cartridge used and control the rotation each time a predetermined level is reached.
• FIG. 1 is also shown the possibility of associating an exhaust gas recycling system which is implemented automatically, by the conduit 16, in the direction of the intake manifold 20, each time one of the valves 5 is obstructed, and that the increase in induced back pressure results in establishing a flow rate through the valve 17, these conditions correspond to a zero accelerator position, therefore a low exhaust gas temperature.
• the recyJfcge will reduce the de ⁇ iz exhaust flow filtered through the cartridge which will remain in action under these conditions and therefore reduce its cooling.
• the valve 17 is of the non-return valve type having a large passage section or better of the type with blades allowing a flow for a few millibars of overpressure.
• the dimensioning of the valve 17 and of the conduit going to the intake manifold 20 is such that this assembly allows recycling of the exhaust gases comprised between 30 to 60% of the flow rate for idling operating conditions.
• FIG. 2 the variant of the device shown is differentiated by the use of a common catalyst 14 for the two cartridges 3 and by the use of butterflies 15, arranged upstream of the cartridges to obstruct the filters in place of the valves 5 , used in the preferred embodiment of Figure 1.
• Figures 3 and 5 show the possibility of having in addition a diesel injection system upstream of the filtration device, controlled from the information collected on the pressure 9 and temperature 10 sensors, disposed upstream of the filters, the computer will be able to adapt the best strategy to keep each of the filters in perfect state of cleanliness, even going so far as to cause additional injection of diesel fuel through the sprayer 11, supplying air 12 and diesel fuel 13.
• These injections are intended to increase the temperature of the exhaust gases when the engine is at full power, so as to raise the filter medium to higher temperature to accelerate the regeneration speed. These injections will only be implemented if a start of clogging of the filter is detected.
• Figure 4 is a variant which uses three filter cartridges instead of two and which allows better conservation of the temperature in the filter medium.
• the computer will trigger the opening of the valve of a first cartridge as soon as a back pressure level of 100 mbar is detected, the opening of the valve of the second cartridge taking place if this level of back pressure of 100 mbar persists.
• this level of back pressure could be different from the value of 100 mbar that we took as an example.
• a variant of the strategy described above could be to use the temperature information in addition, for example each time the temperature ⁇ s will be less than 250 ° C or 300 ° C, decide to close one or more cartridges for a level of back pressure and independently of other conditions of use.
• each of the valves fitted to each cartridge is to be able to isolate them to maintain the high temperature level obtained during the full load of the previous engine and to prevent them from cooling on partial load or the idling which follows, this high temperature favoring the combustion reactions there will be a major advantage in keeping the valve closed a low flow of exhaust gas to maintain these combustion reactions which are very exothe ⁇ niques and which will contribute to raising even these temperatures.
• This operation will be possible by producing valves provided with a calibrated hole of small diameter 24, of less than 1 to a few millimeters, the dimension of which will depend on the engine displacement to allow the necessary flow to pass.
• a variant of this control for a system comprising at least three cartridges, and the dimensioning of each of which will be provided so that the filtration of the exhaust gases for full load conditions can be carried out on only two of it will consist in specializing two of the cartridges for full load operation and one reserved for idle operation and partial loads so as to maintain the filter medium and the catalyst at high temperature.
• cartridges used under full load conditions, and o t ⁇ jr a maximum reduction of all pollutants.
• the computer will change the cartridge used exclusively at idle and replace it with a used full load, as soon as a level of back pressure is detected.
• gas oils having sulfur contents greater than this value of 50 ppm it may be advantageous to use a device such as that described in FIG. 3 in which the gas oil sprayer 11 will be used to inject an organometallic additive solution into diesel from a specific additional tank containing this mixture.
• this device will apply to diesel engines of passenger vehicles, the management of the opening and closing of the valves on each cartridge being done directly from the computer which equips these common rail direct injection engines.
• This closure can, in the same way as that described above, be programmed at idle and at low loads. The temperatures reached on this type of engine will enable one of the two cartridges to be maintained almost permanently a regeneration reaction fast enough to keep it at a non-significant level of fouling.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Exhaust Gas After Treatment (AREA)
• Processes For Solid Components From Exhaust (AREA)
• Filtering Of Dispersed Particles In Gases (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

Country Status (9)

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• 2002
  • 2002-06-04 FR FR0206835A patent/FR2840354A1/fr not_active Withdrawn
• 2003
  • 2003-06-03 MX MXPA04012166A patent/MXPA04012166A/es not_active Application Discontinuation
  • 2003-06-03 WO PCT/FR2003/050004 patent/WO2003102389A2/fr not_active Ceased
  • 2003-06-03 CN CNA03815532XA patent/CN101405486A/zh active Pending
  • 2003-06-03 US US10/516,369 patent/US7314501B2/en not_active Expired - Fee Related
  • 2003-06-03 JP JP2004509250A patent/JP2006515395A/ja active Pending
  • 2003-06-03 EP EP03756052A patent/EP1573181A2/de not_active Withdrawn
  • 2003-06-03 AU AU2003253083A patent/AU2003253083A1/en not_active Abandoned
  • 2003-06-03 CA CA002487942A patent/CA2487942A1/fr not_active Abandoned

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