WO2022243159A1 - Cold-start exhaust-gas emission control - Google Patents

Cold-start exhaust-gas emission control Download PDF

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Publication number
WO2022243159A1
WO2022243159A1 PCT/EP2022/062925 EP2022062925W WO2022243159A1 WO 2022243159 A1 WO2022243159 A1 WO 2022243159A1 EP 2022062925 W EP2022062925 W EP 2022062925W WO 2022243159 A1 WO2022243159 A1 WO 2022243159A1
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WO
WIPO (PCT)
Prior art keywords
exhaust gas
module
aluminosilicate particles
adsorber
adsorber module
Prior art date
Application number
PCT/EP2022/062925
Other languages
German (de)
French (fr)
Inventor
Simone Müller-Hellwig
Hagen SEIFERT
Alexander Krajete
Original Assignee
Audi Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Audi Ag filed Critical Audi Ag
Priority to EP22729131.7A priority Critical patent/EP4341537A1/en
Publication of WO2022243159A1 publication Critical patent/WO2022243159A1/en

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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
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • 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
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • 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
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
    • F01N3/0842—Nitrogen oxides
    • 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 ; Methods of operation or control of catalytic converters
    • F01N3/2053—By-passing catalytic reactors, e.g. to prevent overheating
    • 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 ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • 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
    • 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
    • F01N2510/00—Surface coverings
    • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
    • F01N2510/068—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings
    • 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
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/14—Systems for adding secondary air into exhaust

Definitions

  • the invention relates to a method and a device for removing NOx from the exhaust gas of an internal combustion engine during cold start.
  • WO 2019/072973 A1 discloses a method for reducing the nitrogen oxide content and/or the CO content in an exhaust gas of a vehicle, which comprises water vapor and one or more nitrogen oxides and/or CO, in which a particulate hydrophobic aluminosilicate - Zeolite is brought into contact with the exhaust gas at a temperature of at least 20°C and at least part of the nitrogen oxides and/or the CO from the exhaust gas is adsorbed on its surface and/or in its pores.
  • DE 60 130406 T2 discloses a system for cleaning exhaust gases from diesel or gasoline engines, which on average contain an excess of oxygen, in which system a mixture ratio of the engine periodically changes from a lean mixture ratio to a stoichiometric or rich one mixing ratio is set with an l value below 1.2.
  • the system comprises a combination of an oxidation catalyst effective to accelerate the oxidation of at least NO to NO2, a particulate separator and a NOx adsorption catalyst, the order of this combination of the three operational units in the flow direction of the exhaust gas being as follows : a NOx adsorption catalyst, a particulate separator and an oxidation catalyst, and the NOx adsorption catalyst and the particulate separator are arranged in the same structure.
  • the system reduces the levels of hydrocarbons, carbon monoxide, nitrogen oxides and particulates present in the exhaust.
  • DE 102016219301 A1 relates to a method for cleaning exhaust gas generated by an internal combustion engine, in which the exhaust gas generated by the internal combustion engine is routed through an exhaust gas path in which at least one adsorption element is arranged, on which pollutants contained in the exhaust gas, in particular carbon dioxide, are at least partially bound, and in which the at least one adsorption element is regenerated by at least partial desorption of the bound pollutants, and in which pollutants desorbed from the at least one adsorption element are stored in at least one memory during the desorption.
  • the adsorption element has an adsorption layer made of aluminum oxide and/or aluminum silicate.
  • the invention has set itself the task of making devices and methods available with which the high NOx emission rates during the cold start phase of an internal combustion engine can be reduced.
  • the object is achieved according to the invention by a method having the features of claim 1 and a device having the features of claim 8. Configurations and developments of the invention result from the dependent claims, the description and the illustrations.
  • the exhaust gas composition of modern combustion engines is NO-heavy, the NO2 content is very low. While a plethora of materials can remove NO2, adsorptive removal of NO is far more difficult to accomplish.
  • the targeted metering of oxygen or air into the exhaust gas stream makes it possible to reduce NOx emissions during the cold start phase, even in vehicles with high engines.
  • the introduction of oxygen or air into the exhaust line shifts the reaction equilibrium from NO to NO2, which facilitates the absorption of NOx in an adsorber material, since NO2 is bound much more easily than NO.
  • the invention relates to a method for removing NO and/or NOx from an exhaust gas stream of an internal combustion engine during the cold start phase, i. H. preferably in the first 120 to 180 seconds after starting the engine, in which the exhaust gas flow and an oxygen-containing gas flow are simultaneously passed through an adsorber module containing aluminosilicate particles, and NO and/or NOx are oxidized by the oxygen and adsorbed on the aluminosilicate particles.
  • the aluminosilicate particles can be regenerated by heating, i. H. they release the adsorbed nitrogen oxides again and can adsorb nitrogen oxides again after cooling down.
  • the method according to the invention is carried out in a temperature range from -40° C. to 40° C. outside temperature and at a flow rate of at least 60 m 3 /h exhaust gas and the method according to the invention has a space-time yield of at least
  • the total volume of the aluminosilicate particles contained in the adsorber module is 1 to 4 L, e.g. B. 1 to 3 L, in particular 2 to 2.5 L, for example 2.2 L.
  • the ratio of the flow rates of exhaust gas and oxygen-containing gas is from 10:1 to 1:1, for example 5:1 to 3: 1.
  • aluminosilicate particles are used as adsorber material.
  • suitable aluminosilicates are feldspars and zeolites, such as zeolite A, zeolite Y or zeolite ZSM-5.
  • the Zeolite particles have a Si:Al molar ratio in the range from 500:1 to 5:1, for example from 40:1 to 10:1.
  • aluminosilicate particles are used which contain no metals as promoters.
  • the aluminosilicate particles have a bulk density of 650 to 750 kg/m 3 and an average diameter in the range from 0.1 to 0.7 mm, for example 0.15 to 0.6 mm.
  • the aluminosilicate particles can be regenerated by heating in order to release the adsorbed nitrogen oxides and restore the original adsorption capacity.
  • the aluminosilicate particles can be used over a longer period of time and over many cold-start phases of the combustion engine.
  • the aluminosilicate particles are regenerated by passing a hot exhaust gas stream through the adsorber module. No additional oxygen is supplied to the adsorber module during regeneration.
  • the exhaust gas stream leaving the adsorber module is fed to an SCR module.
  • the SCR module carries out a selective catalytic reduction (SCR) of the nitrogen oxides contained in the exhaust gas flow.
  • the exhaust gas flow is routed through the adsorber module intermittently during the cold start phase and/or to regenerate the aluminosilicate particles from time to time.
  • the exhaust gas stream is permanently passed through the adsorber module and the SCR module, but only during the cold start phase is an oxygen-containing gas stream additionally passed through the adsorber module.
  • the invention also relates to a device suitable for carrying out the method according to the invention, which comprises an adsorber module containing aluminosilicate particles arranged in an exhaust system of an internal combustion engine and a module for the selective catalytic reduction of nitrogen oxides (SCR module). Furthermore, the device comprises means for metering an oxygen-containing additional gas into the adsorber module.
  • the adsorber module is positioned in the exhaust system of the internal combustion engine in such a way that the exhaust gas stream flows through the adsorber module at least during the cold start phase.
  • the exhaust gas module is arranged in a bypass line (bypass) of an exhaust gas cleaning device (e.g. three-way catalytic converter, oxidation catalytic converter, reduction catalytic converter (SCR)) downstream of the internal combustion engine and means (e.g. electronically controlled valves) are provided, which direct the exhaust gas through the adsorber module according to the invention only during the cold start phase.
  • an exhaust gas cleaning device e.g. three-way catalytic converter, oxidation catalytic converter, reduction catalytic converter (SCR)
  • SCR reduction catalytic converter
  • the adsorber module is connected upstream of the SCR module in the exhaust system.
  • the exhaust system comprises means for directing an exhaust gas flow selectively through the adsorber module or past it, for example a bypass line provided with valve flaps.
  • the adsorber module is connected upstream of the exhaust gas cleaning device in such a way that the exhaust gas stream flows permanently through the adsorber module according to the invention.
  • the emission control device When the emission control device has reached its operating temperature after the cold start phase, it removes the nitrogen oxides from the exhaust gas flow.
  • the adsorber module is not heated, the working temperature is the climatic ambient temperature. Due to the high reactivity Due to the oxygen and aluminosilicate particle viability, the adsorber module according to the invention is able to remove nitrogen oxides from the exhaust gas stream in a temperature range from -40°C to 40°C outside temperature without external heat supply.
  • the aluminosilicate particles are arranged in an exchangeable cartridge.
  • a replaceable cartridge filled with aluminosilicate particles makes the change much easier.
  • the adsorption capacity of the aluminosilicate particles can decrease, for example due to the deposits of impurities contained in the exhaust gas, so that it cannot be sufficiently restored even through regeneration. If the adsorption capacity of the aluminosilicate particles in the cartridge is permanently exhausted, it is simply exchanged for a new cartridge.
  • the cartridge has a volume in the range from 25 mL to 4,000 L, for example from 2 L to 4 L. This low volume allows miniaturization or a compact design of the cold-start adsorber module.
  • the cartridge is made of metal. In another embodiment, the cartridge is a plastic cartridge. The cartridge can have different shapes. In one embodiment, the cartridge is cylindrical and has a circular cross-section. In another embodiment, the cartridge has an elliptical cross-section. In yet another embodiment, the cartridge is in the form of a prism, such as a quadrangular, pentagonal, hexagonal, or octagonal prism.
  • the cartridge has a perforated base and/or lid. This makes it easier for exhaust gas to flow through the cartridge and also retains the aluminosilicate particles in the cartridge.
  • the perforation can consist of holes or slots, for example. It is important that the diameter of the holes or the width of the slots is smaller than the diameter of the aluminosilicate particles in order to effectively retain them in the cartridge.
  • the device according to the invention comprises means for metering an additional gas containing oxygen into the adsorber module.
  • these means include a dosing line that opens into the adsorber module and means for gas dosing such as valves, reducing valves or compressors.
  • these means comprise a dosing line which opens into the exhaust line at the entrance of the adsorber module and means for gas dosing.
  • the oxygen-containing makeup gas is pure oxygen.
  • the oxygen-containing supplemental gas is compressed air.
  • the oxygen-containing supplemental gas is ambient air, optionally in compressed form.
  • the implementation in the vehicle can take place, for example, as follows:
  • the adsorber module is positioned in the exhaust gas flow in front of the SCR module.
  • the cold exhaust gas (when restarting) is passed through the adsorber module for a few seconds and at the same time an oxygen-containing gas flow (pure oxygen, compressed air or ambient air) is passed through the adsorber module until the temperatures in the existing exhaust gas catalytic converter system are sufficient for this can perform its function.
  • the exhaust jet can be routed accordingly via a flap control so that only cold exhaust gas is routed through the adsorber module.
  • the loaded material can be regenerated on-board by passing sufficiently hot exhaust gas through the adsorber module. This stream should be cleaned via the SCR system.
  • the adsorber material can be loaded and unloaded very frequently.
  • a replacement cartridge can be used, which may be replaced at service intervals.
  • Adsorbed on the aluminosilicate particles Nitrogen oxides can be desorbed and recycled and z. B. be used as a raw material for the production of nitro compounds.
  • the solution according to the invention makes it possible to reduce NOx emissions from internal combustion engines during cold starts under extreme flow conditions with space-time yields of at least 30,000 Ir 1 under real conditions (RDE, real drive emissions).
  • RDE real drive emissions
  • With only 2.2 L of adsorber material at least 60 m 3 /h of exhaust gas can be cleaned effectively in a low temperature range (outside temperature - 40 to 40°C).
  • High NOx absorption rates of approx. 50% can also be achieved with an exhaust gas stream in which NO makes up > 99% of the nitrogen oxides, even with an unfavorable combination of high exhaust gas flows under real cold start conditions and without external heat supply.
  • the nitrogen oxide content in the exhaust gas flow during the cold start phase is reduced by up to 67%.
  • FIG. 1 shows an example diagram of the contents of nitrogen oxides and oxygen in an exhaust gas flow leaving an exhaust gas module according to the invention over time
  • FIG. 2 shows an example diagram of the contents of nitrogen oxides and oxygen in an exhaust gas stream at the inlet and at the outlet of an exhaust gas module according to the invention over time.
  • Example 1 In a laboratory test, in a cylindrical plastic cartridge
  • Figure 1 shows the results of the measurement. A maximum NOx uptake rate of 67% was determined; this corresponds to a space-time yield of 14,400 Ir 1 . Virtually no NO is adsorbed without the addition of oxygen.
  • An embodiment of the exhaust module according to the invention was in egg nem field test with a highly motorized (engine power> 350 hp)
  • Example 2 Car tested under real conditions. For this purpose, 2.2 L of the adsorber material from Example 1 were placed in a cylindrical cartridge (16 cm in diameter) and covered with 1.5 L of silica gel to protect against moisture. The raw emission gas of the car's ICE was bundled via 2 tapers on the double exhaust and introduced via 2 inlets into the upper segment of the cartridge, which was perforated at the bottom. In addition, during the cold start-up phase (0 s to 120 s after engine start) 50-100 L/min of pure oxygen from a compressed gas bottle are continuously introduced. With a testo 340 flue gas analyzer (Testo SE & Co.
  • FIG. 2 shows the NOx content of the exhaust gas stream and at the outlet of the exhaust gas module according to the invention over time during the cold start phase (0 s to 130 s after engine start).
  • the NOx absorption rates are in spite of high motorization (> 350 hp) and high volume emissions of at least 60 m 3 / h at about 48%, the space-time yields are high and are in the range of at least 30,000 h 1 .

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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)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

The invention relates to a method and a device for removing NOx from the exhaust gas of an internal combustion engine during cold starting.

Description

AUDI AG Kaltstart-Abgasreinigung AUDI AG cold start emission control
BESCHREIBUNG: Die Erfindung betrifft ein Verfahren und eine Vorrichtung zur Entfernung von NOx aus dem Abgas eines Verbrennungsmotors während des Kaltstarts. DESCRIPTION: The invention relates to a method and a device for removing NOx from the exhaust gas of an internal combustion engine during cold start.
Der Verbrennungsprozess von Kohlenwasserstoffen (Treibstoffe, „Fuels“) liefert Wärmeenergie für den Antrieb und erzeugt Emissionen wie CO2 und NOx. Während das C02-Problem technisch noch nicht gelöst wurde, gibt es für NOx diverse kommerzielle Lösungen (z. B. Dreiwegekatalysator, Harn stoffzugabe), welche allesamt erst ab einer bestimmten Arbeitstemperatur von ca. 200°C funktionieren. In der sogenannten Kaltstartphase, kurz nach Motorzündung, erzeugen sowohl Benzin- als auch Dieselfahrzeuge substan- tielle NOx-Emissionen, welche mit gegenwärtigen technischen Ansätzen noch nicht verringert werden konnten. The combustion process of hydrocarbons (fuels) provides thermal energy for propulsion and generates emissions such as CO2 and NOx. While the CO2 problem has not yet been technically solved, there are various commercial solutions for NOx (e.g. three-way catalytic converter, addition of urea), all of which only work above a certain working temperature of around 200°C. In the so-called cold-start phase, shortly after the engine is ignited, both petrol and diesel vehicles produce substantial NOx emissions, which cannot yet be reduced using current technical approaches.
Aus der WO 2019 / 072973 A1 ist ein Verfahren zur Verringerung des Stick oxidgehalts und/oder des CO-Gehalts in einem Abgas eines Fahrzeugs, das Wasserdampf und ein oder mehrere Stickoxide und/oder CO umfasst, be kannt, bei dem ein teilchenförmiger hydrophober Alumosilikat-Zeolith bei ei ner Temperatur von mindestens 20°C mit dem Abgas in Kontakt gebracht wird und mindestens einen Teil der Stickoxide und/oder des CO aus dem Abgas auf seiner Oberfläche und / oder in seinen Poren adsorbiert. WO 2019/072973 A1 discloses a method for reducing the nitrogen oxide content and/or the CO content in an exhaust gas of a vehicle, which comprises water vapor and one or more nitrogen oxides and/or CO, in which a particulate hydrophobic aluminosilicate - Zeolite is brought into contact with the exhaust gas at a temperature of at least 20°C and at least part of the nitrogen oxides and/or the CO from the exhaust gas is adsorbed on its surface and/or in its pores.
Die DE 60 130406 T2 offenbart ein System zur Reinigung von Abgasen aus Diesel- oder Benzinmotoren, die im Mittel einen Überschuss an Sauerstoff enthalten, wobei in dem System ein Mischverhältnis des Motors periodisch von einem mageren Mischverhältnis zu einem stöchiometrischen oder fetten Mischverhältnis mit einem l-Wert unter 1,2 eingestellt wird. Das System um fasst eine Kombination aus einem Oxidationskatalysator, der zur Beschleu nigung der Oxidation von wenigstens NO zu NO2 wirksam ist, einem Parti kelseparator und einem NOx-Adsorptionskatalysator, wobei die Reihenfolge dieser Kombination der drei Betriebseinheiten in der Flussrichtung des Ab gases wie folgt ist: ein NOx-Adsorptionskatalysator, ein Partikelseparator und ein Oxidationskatalysator, und der NOx-Adsorptionskatalysator und der Parti kelseparator in der gleichen Struktur angeordnet sind. Das System reduziert die Mengen an Kohlenwasserstoffen, Kohlenmonoxid, Stickstoffoxiden und Partikeln, die in dem Abgas vorhanden sind. DE 60 130406 T2 discloses a system for cleaning exhaust gases from diesel or gasoline engines, which on average contain an excess of oxygen, in which system a mixture ratio of the engine periodically changes from a lean mixture ratio to a stoichiometric or rich one mixing ratio is set with an l value below 1.2. The system comprises a combination of an oxidation catalyst effective to accelerate the oxidation of at least NO to NO2, a particulate separator and a NOx adsorption catalyst, the order of this combination of the three operational units in the flow direction of the exhaust gas being as follows : a NOx adsorption catalyst, a particulate separator and an oxidation catalyst, and the NOx adsorption catalyst and the particulate separator are arranged in the same structure. The system reduces the levels of hydrocarbons, carbon monoxide, nitrogen oxides and particulates present in the exhaust.
Die DE 102016219301 A1 betrifft ein Verfahren zum Reinigen von durch eine Brennkraftmaschine erzeugtem Abgas, bei dem das durch die Brenn kraftmaschine erzeugte Abgas durch einen Abgaspfad geleitet wird, in dem mindestens ein Adsorptionselement angeordnet ist, an dem in dem Abgas enthaltene Schadstoffe, insbesondere Kohlendioxid, zumindest teilweise ge bunden werden, und bei dem das mindestens eine Adsorptionselement durch zumindest teilweise Desorption der gebundenen Schadstoffe regene riert wird, und bei dem während der Desorption von dem mindestens einen Adsorptionselement desorbierte Schadstoffe in mindestens einem Speicher gespeichert werden. Das Adsorptionselement weist eine Adsorptionsschicht aus Aluminiumoxid und/oder Aluminiumsilikat auf. DE 102016219301 A1 relates to a method for cleaning exhaust gas generated by an internal combustion engine, in which the exhaust gas generated by the internal combustion engine is routed through an exhaust gas path in which at least one adsorption element is arranged, on which pollutants contained in the exhaust gas, in particular carbon dioxide, are at least partially bound, and in which the at least one adsorption element is regenerated by at least partial desorption of the bound pollutants, and in which pollutants desorbed from the at least one adsorption element are stored in at least one memory during the desorption. The adsorption element has an adsorption layer made of aluminum oxide and/or aluminum silicate.
Vor diesem Hintergrund hat sich die Erfindung die Aufgabe gestellt, Vorrich- tungen und Verfahren zur Verfügung zu stellen, mit denen die hohen NOx- Emissionsraten während der Kaltstartphase eines Verbrennungsmotors ver ringert werden können. Against this background, the invention has set itself the task of making devices and methods available with which the high NOx emission rates during the cold start phase of an internal combustion engine can be reduced.
Die Aufgabe wird erfindungsgemäß gelöst durch ein Verfahren mit den Merkmalen des Anspruchs 1 und eine Vorrichtung mit den Merkmalen des Anspruchs 8. Ausgestaltungen und Weiterbildungen der Erfindung ergeben sich aus den abhängigen Ansprüchen, der Beschreibung und den Abbildun gen. Die Abgaszusammensetzung moderner Verbrennungsmotoren ist NO-lastig, der NO2 Anteil ist sehr gering. Während eine Fülle von Materialien NO2 ent fernen kann, ist die adsorptive Entfernung von NO ungleich schwerer zu be werkstelligen. Erfindungsgemäß gelingt es durch die gezielte Zudosierung von Sauerstoff oder Luft in den Abgasstrom, auch bei hoch motorisierten Fahrzeugen die NOx-Emissionen während der Kaltstartphase zu verringern. Durch Einleitung von Sauerstoff oder Luft in den Abgasstrang verschiebt sich das Reaktionsgleichgewicht von NO zu NO2, was die Aufnahme von NOx in einem Adsorbermaterial erleichtert, da NO2 wesentlich leichter gebunden wird als NO. The object is achieved according to the invention by a method having the features of claim 1 and a device having the features of claim 8. Configurations and developments of the invention result from the dependent claims, the description and the illustrations. The exhaust gas composition of modern combustion engines is NO-heavy, the NO2 content is very low. While a plethora of materials can remove NO2, adsorptive removal of NO is far more difficult to accomplish. According to the invention, the targeted metering of oxygen or air into the exhaust gas stream makes it possible to reduce NOx emissions during the cold start phase, even in vehicles with high engines. The introduction of oxygen or air into the exhaust line shifts the reaction equilibrium from NO to NO2, which facilitates the absorption of NOx in an adsorber material, since NO2 is bound much more easily than NO.
Gegenstand der Erfindung ist ein Verfahren zur Entfernung von NO und/oder NOx aus einem Abgasstrom eines Verbrennungsmotors während der Kalt startphase, d. h. vorzugsweise in den ersten 120 bis 180 Sekunden nach dem Motorstart, bei dem der Abgasstrom und ein Sauerstoff enthaltender Gasstrom gleichzeitig durch ein Alumosilikatpartikel enthaltendes Adsorber modul geleitet wird, und NO und/oder NOx durch den Sauerstoff oxidiert und an den Alumosilikatpartikeln adsorbiert werden. Die Alumosilikatpartikel sind durch Erhitzen regenerierbar, d. h. sie geben die adsorbierten Stickoxide wieder ab und können nach Abkühlen erneut Stickoxide adsorbieren. The invention relates to a method for removing NO and/or NOx from an exhaust gas stream of an internal combustion engine during the cold start phase, i. H. preferably in the first 120 to 180 seconds after starting the engine, in which the exhaust gas flow and an oxygen-containing gas flow are simultaneously passed through an adsorber module containing aluminosilicate particles, and NO and/or NOx are oxidized by the oxygen and adsorbed on the aluminosilicate particles. The aluminosilicate particles can be regenerated by heating, i. H. they release the adsorbed nitrogen oxides again and can adsorb nitrogen oxides again after cooling down.
In einer Ausführungsform wird das erfindungsgemäße Verfahren in einem Temperaturbereich von -40°C bis 40°C Außentemperatur und bei einer Durchflussrate von mindestens 60 m3/h Abgas durchgeführt und weist das erfindungsgemäße Verfahren eine Raumzeitausbeute von mindestensIn one embodiment, the method according to the invention is carried out in a temperature range from -40° C. to 40° C. outside temperature and at a flow rate of at least 60 m 3 /h exhaust gas and the method according to the invention has a space-time yield of at least
30.000 h_1 auf. In einer Ausführungsform beträgt das Gesamtvolumen der im Adsorbermodul enthaltenen Alumosilikatpartikel 1 bis 4 L, z. B. 1 bis 3 L, ins besondere 2 bis 2,5 L, beispielsweise 2,2 L. In einer Ausführungsform be trägt das Verhältnis der Durchflussraten von Abgas und sauerstoffhaltigem Gas von 10:1 bis 1 : 1 , beispielsweise von 5: 1 bis 3: 1. 30,000 h _1 on. In one embodiment, the total volume of the aluminosilicate particles contained in the adsorber module is 1 to 4 L, e.g. B. 1 to 3 L, in particular 2 to 2.5 L, for example 2.2 L. In one embodiment, the ratio of the flow rates of exhaust gas and oxygen-containing gas is from 10:1 to 1:1, for example 5:1 to 3: 1.
Als Adsorbermaterial werden erfindungsgemäß Alumosilikatpartikel einge setzt. Beispiele geeigneter Alumosilikate sind Feldspate und Zeolithe, wie Zeolith A, Zeolith Y oder Zeolith ZSM-5. In einer Ausführungsform weisen die Zeolithpartikel ein Molverhältnis Si: AI im Bereich von 500:1 bis 5:1 auf, bei spielsweise von 40:1 bis 10:1. Erfindungsgemäß werden Alumosilikatpartikel eingesetzt, die keine Metalle als Promotoren enthalten. In einer Ausführungsform weisen die Alumosilikatpartikel eine Schüttdichte (Bulk Density) von 650 bis 750 kg/m3 und einen mittleren Durchmesser im Bereich von 0,1 bis 0,7 mm, beispielsweise 0,15 bis 0,6 mm, auf. According to the invention, aluminosilicate particles are used as adsorber material. Examples of suitable aluminosilicates are feldspars and zeolites, such as zeolite A, zeolite Y or zeolite ZSM-5. In one embodiment, the Zeolite particles have a Si:Al molar ratio in the range from 500:1 to 5:1, for example from 40:1 to 10:1. According to the invention, aluminosilicate particles are used which contain no metals as promoters. In one embodiment, the aluminosilicate particles have a bulk density of 650 to 750 kg/m 3 and an average diameter in the range from 0.1 to 0.7 mm, for example 0.15 to 0.6 mm.
Einer der Vorteile des erfindungsgemäßen Verfahrens ist, dass die Alumosi- likatpartikel durch Erhitzen regeneriert werden können, um die adsorbierten Stickoxide freizusetzen und die ursprüngliche Adsorptionskapazität wieder herzustellen. Dadurch lassen sich die Alumosilikatpartikel über einen länge ren Zeitraum und über viele Kaltstartphasen des Verbrennungsmotors nut zen. In einer Ausführungsform des Verfahrens werden die Alumosilikatparti- kel regeneriert, indem ein heißer Abgasstrom durch das Adsorbermodul ge leitet wird. Während der Regeneration wird dem Adsorbermodul kein zusätz licher Sauerstoff zugeführt. One of the advantages of the method according to the invention is that the aluminosilicate particles can be regenerated by heating in order to release the adsorbed nitrogen oxides and restore the original adsorption capacity. As a result, the aluminosilicate particles can be used over a longer period of time and over many cold-start phases of the combustion engine. In one embodiment of the method, the aluminosilicate particles are regenerated by passing a hot exhaust gas stream through the adsorber module. No additional oxygen is supplied to the adsorber module during regeneration.
In einer Ausführungsform des erfindungsgemäßen Verfahrens wird der das Adsorbermodul verlassende Abgasstrom einem SCR-Modul zugeleitet. Das SCR-Modul führt eine selektive katalytische Reduktion (SCR) der im Ab gasstrom enthaltenen Stickoxide durch. In einer Ausführungsform des Ver fahrens wird der Abgasstrom intermittierend durch das Adsorbermodul gelei tet, während der Kaltstartphase und/oder um die Alumosilikatpartikel von Zeit zu Zeit zu regenerieren. In einer anderen Ausführungsform des Verfahrens wird der Abgasstrom permanent durch das Adsorbermodul und das SCR- Modul geleitet, jedoch wird nur während der Kaltstartphase zusätzlich auch ein Sauerstoff enthaltender Gasstrom durch das Adsorbermodul geleitet. Nachdem der Verbrennungsmotor seine Betriebstemperatur erreicht hat, desorbiert der heiße Abgasstrom die im Adsorbermodul adsorbierten Stick oxide, die dann im nachfolgenden SCR-Modul zu Stickstoff reduziert werden. So steht für einen nachfolgenden Kaltstart wieder die volle Adsorptionskapa zität des Adsorbermoduls zur Verfügung. Gegenstand der Erfindung ist auch eine zur Durchführung des erfindungs gemäßen Verfahrens geeignete Vorrichtung, die ein in einem Abgasstrang eines Verbrennungsmotors angeordnetes, Alumosilikatpartikel enthaltendes Adsorbermodul und ein Modul zur selektiven katalytischen Reduktion von Stickoxiden (SCR-Modul) umfasst. Weiterhin umfasst die Vorrichtung Mittel zur Dosierung eines Sauerstoff enthaltenden Zusatzgases in das Adsorber modul. In one embodiment of the method according to the invention, the exhaust gas stream leaving the adsorber module is fed to an SCR module. The SCR module carries out a selective catalytic reduction (SCR) of the nitrogen oxides contained in the exhaust gas flow. In one embodiment of the method, the exhaust gas flow is routed through the adsorber module intermittently during the cold start phase and/or to regenerate the aluminosilicate particles from time to time. In another embodiment of the method, the exhaust gas stream is permanently passed through the adsorber module and the SCR module, but only during the cold start phase is an oxygen-containing gas stream additionally passed through the adsorber module. After the combustion engine has reached its operating temperature, the hot exhaust gas stream desorbs the nitrogen oxides adsorbed in the adsorber module, which are then reduced to nitrogen in the downstream SCR module. This means that the full adsorption capacity of the adsorber module is available again for a subsequent cold start. The invention also relates to a device suitable for carrying out the method according to the invention, which comprises an adsorber module containing aluminosilicate particles arranged in an exhaust system of an internal combustion engine and a module for the selective catalytic reduction of nitrogen oxides (SCR module). Furthermore, the device comprises means for metering an oxygen-containing additional gas into the adsorber module.
Das Adsorbermodul wird so in dem Abgasstrang des Verbrennungsmotors positioniert, dass der Abgasstrom zumindest während der Kaltstartphase durch das Adsorbermodul strömt. The adsorber module is positioned in the exhaust system of the internal combustion engine in such a way that the exhaust gas stream flows through the adsorber module at least during the cold start phase.
In einer Ausführungsform ist das Abgasmodul in einer Umgehungsleitung (Bypass) einer dem Verbrennungsmotor nachgeschalteten Abgasreinigungs- Vorrichtung (z. B. Dreiwegekatalysator, Oxidationskatalysator, Reduktionska talysator (SCR)) angeordnet und es sind Mittel (z. B. elektronisch gesteuerte Ventile) vorgesehen, die das Abgas nur während der Kaltstartphase durch das erfindungsgemäße Adsorbermodul leiten. In einer anderen Ausführungsform ist das Adsorbermodul dem SCR-Modul im Abgasstrang vorgeschaltet. In einerweiteren Ausführungsform umfasst der Abgasstrang Mittel, um einen Abgasstrom wahlweise durch das Adsor bermodul oder an diesem vorbei zu leiten, beispielsweise eine mit Ventil klappen versehene Umgehungsleitung (Bypass). In one embodiment, the exhaust gas module is arranged in a bypass line (bypass) of an exhaust gas cleaning device (e.g. three-way catalytic converter, oxidation catalytic converter, reduction catalytic converter (SCR)) downstream of the internal combustion engine and means (e.g. electronically controlled valves) are provided, which direct the exhaust gas through the adsorber module according to the invention only during the cold start phase. In another embodiment, the adsorber module is connected upstream of the SCR module in the exhaust system. In a further embodiment, the exhaust system comprises means for directing an exhaust gas flow selectively through the adsorber module or past it, for example a bypass line provided with valve flaps.
In einer anderen Ausführungsform ist das Adsorbermodul der Abgasreini gungsvorrichtung so vorgeschaltet, dass der Abgasstrom permanent durch das erfindungsgemäße Adsorbermodul strömt. Wenn die Abgasreinigungs vorrichtung nach der Kaltstartphase ihre Betriebstemperatur erreicht hat, ent- fernt diese die Stickoxide aus dem Abgasstrom. In another embodiment, the adsorber module is connected upstream of the exhaust gas cleaning device in such a way that the exhaust gas stream flows permanently through the adsorber module according to the invention. When the emission control device has reached its operating temperature after the cold start phase, it removes the nitrogen oxides from the exhaust gas flow.
Es ist keine Heizvorrichtung zur gezielten Erwärmung des Adsorbermoduls vorgesehen. Das Adsorbermodul wird nicht geheizt, die Arbeitstemperatur ist die klimatische bedingte Umgebungstemperatur. Aufgrund der hohen Reakti- vität des Sauerstoffs und der Alumosilikatpartikel ist das erfindungsgemäße Adsorbermodul in der Lage, in einem Temperaturbereich von -40°C bis 40°C Außentemperatur ohne externe Wärmezufuhr Stickoxide aus dem Ab gasstrom zu entfernen. There is no heating device for targeted heating of the adsorber module. The adsorber module is not heated, the working temperature is the climatic ambient temperature. Due to the high reactivity Due to the oxygen and aluminosilicate particle viability, the adsorber module according to the invention is able to remove nitrogen oxides from the exhaust gas stream in a temperature range from -40°C to 40°C outside temperature without external heat supply.
In einer Ausführungsform des Adsorbermoduls sind die Alumosilikatpartikel in einer austauschbaren Kartusche angeordnet. Eine mit Alumosilikatparti- keln befüllte austauschbare Kartusche erleichtert den Wechsel erheblich. Im Laufe der Zeit kann die Adsorptionskapazität der Alumosilikatpartikel bei spielsweise durch Ablagerung von im Abgas enthaltenen Verunreinigungen so nachlassen, dass sie auch durch die Regeneration nicht ausreichend wie derhergestellt werden kann. Wenn die Adsorptionskapazität der Alumosili katpartikel in der Kartusche dauerhaft erschöpft ist, wird diese einfach gegen eine neue Kartusche getauscht. In one embodiment of the adsorber module, the aluminosilicate particles are arranged in an exchangeable cartridge. A replaceable cartridge filled with aluminosilicate particles makes the change much easier. Over time, the adsorption capacity of the aluminosilicate particles can decrease, for example due to the deposits of impurities contained in the exhaust gas, so that it cannot be sufficiently restored even through regeneration. If the adsorption capacity of the aluminosilicate particles in the cartridge is permanently exhausted, it is simply exchanged for a new cartridge.
In einer Ausführungsform weist die Kartusche ein Volumen im Bereich von 25 mL bis 4.000 L auf, beispielsweise von 2 L bis 4 L. Dieses geringe Volu men erlaubt eine Miniaturisierung bzw. Kompaktbauweise des Kaltstart- Adsorbermoduls. In one embodiment, the cartridge has a volume in the range from 25 mL to 4,000 L, for example from 2 L to 4 L. This low volume allows miniaturization or a compact design of the cold-start adsorber module.
In einer Ausführungsform ist die Kartusche aus Metall gefertigt. In einer an deren Ausführungsform ist die Kartusche eine Plastikkartusche. Die Kartu sche kann verschiedene Formen haben. In einer Ausführungsform ist die Kartusche zylindrisch und weist einen kreisförmigen Querschnitt auf. In einer anderen Ausführungsform weist die Kartusche einen elliptischen Querschnitt auf. In wieder einer anderen Ausführungsform hat die Kartusche die Form eines Prismas, beispielsweise eines viereckigen, fünfeckigen, sechseckigen oder achteckigen Prismas. In one embodiment, the cartridge is made of metal. In another embodiment, the cartridge is a plastic cartridge. The cartridge can have different shapes. In one embodiment, the cartridge is cylindrical and has a circular cross-section. In another embodiment, the cartridge has an elliptical cross-section. In yet another embodiment, the cartridge is in the form of a prism, such as a quadrangular, pentagonal, hexagonal, or octagonal prism.
In einer Ausführungsform weist die Kartusche einen perforierten Boden und/oder Deckel auf. Dadurch wird zum einen die Durchströmung der Kartu sche mit Abgas erleichtert, und zum anderen werden die Alumosilikatpartikel in der Kartusche zurückgehalten. Die Perforation kann beispielsweise aus Löchern oder Schlitzen bestehen. Wichtig ist dabei, dass der Durchmesser der Löcher bzw. die Breite der Schlitze kleiner ist als der Durchmesser der Alumosilikatpartikel, um diese effektiv in der Kartusche zurückzuhalten. In one embodiment, the cartridge has a perforated base and/or lid. This makes it easier for exhaust gas to flow through the cartridge and also retains the aluminosilicate particles in the cartridge. The perforation can consist of holes or slots, for example. It is important that the diameter of the holes or the width of the slots is smaller than the diameter of the aluminosilicate particles in order to effectively retain them in the cartridge.
Die erfindungsgemäße Vorrichtung umfasst Mittel zur Dosierung eines Sau erstoff enthaltenden Zusatzgases in das Adsorbermodul. In einer Ausfüh rungsform umfassen diese Mittel eine in das Adsorbermodul mündende Do sierleitung und Mittel zur Gasdosierung wie Ventile, Reduzierventile oder Kompressoren. In einer anderen Ausführungsform umfassen diese Mittel eine am Eingang des Adsorbermoduls in den Abgasstrang mündende Do sierleitung und Mittel zur Gasdosierung. The device according to the invention comprises means for metering an additional gas containing oxygen into the adsorber module. In one embodiment, these means include a dosing line that opens into the adsorber module and means for gas dosing such as valves, reducing valves or compressors. In another embodiment, these means comprise a dosing line which opens into the exhaust line at the entrance of the adsorber module and means for gas dosing.
In einer Ausführungsform ist das Sauerstoff enthaltende Zusatzgas reiner Sauerstoff. In einer anderen Ausführungsform ist das Sauerstoff enthaltende Zusatzgas Druckluft. In einer anderen Ausführungsform ist das Sauerstoff enthaltende Zusatzgas Umgebungsluft, gegebenenfalls in komprimierter Form. In one embodiment, the oxygen-containing makeup gas is pure oxygen. In another embodiment, the oxygen-containing supplemental gas is compressed air. In another embodiment, the oxygen-containing supplemental gas is ambient air, optionally in compressed form.
Die Umsetzung im Fahrzeug kann beispielsweise folgendermaßen erfolgen: Das Adsorbermodul wird im Abgasstrom vor dem SCR-Modul positioniert. Das kalte Abgas (bei Neustart) wird einige Sekunden durch das Adsorber modul geleitet und gleichzeitig wird ein sauerstoffhaltiger Gasstrom (reiner Sauerstoff, Druckluft oder Umgebungsluft) durch das Adsorbermodul geleitet, bis die Temperaturen im vorhandenen Abgas-Katalysator-System ausrei chend sind, damit dieses seine Funktion ausüben kann. Über eine Klappens teuerung kann der Abgasstrahl entsprechend geleitet werden, damit nur kal tes Abgas durch das Adsorbermodul geleitet wird. Eine Regeneration des beladenen Materials on-board kann erfolgen, indem genügend heißes Abgas durch das Adsorbermodul geleitet wird. Dieser Strom sollte über das SCR- System gereinigt werden. Das Adsorbermaterial kann sehr häufig beladen und entladen werden. The implementation in the vehicle can take place, for example, as follows: The adsorber module is positioned in the exhaust gas flow in front of the SCR module. The cold exhaust gas (when restarting) is passed through the adsorber module for a few seconds and at the same time an oxygen-containing gas flow (pure oxygen, compressed air or ambient air) is passed through the adsorber module until the temperatures in the existing exhaust gas catalytic converter system are sufficient for this can perform its function. The exhaust jet can be routed accordingly via a flap control so that only cold exhaust gas is routed through the adsorber module. The loaded material can be regenerated on-board by passing sufficiently hot exhaust gas through the adsorber module. This stream should be cleaned via the SCR system. The adsorber material can be loaded and unloaded very frequently.
Alternativ kann eine Wechsel kartusche verwendet werden, die ggf. im Ser viceintervall ausgetauscht wird. Die an den Alumosilikatpartikeln adsorbierten Stickoxide können desorbiert und einem Kreislauf zugeführt und z. B. als Rohstoff für die Herstellung von Nitroverbindungen genutzt werden. Alternatively, a replacement cartridge can be used, which may be replaced at service intervals. Adsorbed on the aluminosilicate particles Nitrogen oxides can be desorbed and recycled and z. B. be used as a raw material for the production of nitro compounds.
Die erfindungsgemäße Lösung ermöglicht die Verringerung der NOx- Emissionen von Verbrennungsmotoren im Kaltstart unter extremen Durch flussbedingungen mit Raumzeitausbeuten von mindestens 30.000 Ir1 unter Realbedingungen (RDE, real drive emissions). Mit nur 2.2 L Adsorber material können mindestens 60 m3/h Abgas effektiv in einem niedrigen Tem peraturbereich (- 40 bis 40°C Außentemperatur) gereinigt werden. Es lassen sich auch bei einem Abgasstrom, in dem NO > 99% der Stickoxide aus macht, hohe NOx-Aufnahmeraten von ca. 50% erzielen, selbst bei einer un vorteilhaften Kombination aus hohen Abgasflüssen unter realen Kaltstartbe dingungen und ohne externe Wärmezufuhr. Der Stickoxidgehalt im Ab gasstrom während der Kaltstartphase wird um bis zu 67% verringert. The solution according to the invention makes it possible to reduce NOx emissions from internal combustion engines during cold starts under extreme flow conditions with space-time yields of at least 30,000 Ir 1 under real conditions (RDE, real drive emissions). With only 2.2 L of adsorber material, at least 60 m 3 /h of exhaust gas can be cleaned effectively in a low temperature range (outside temperature - 40 to 40°C). High NOx absorption rates of approx. 50% can also be achieved with an exhaust gas stream in which NO makes up > 99% of the nitrogen oxides, even with an unfavorable combination of high exhaust gas flows under real cold start conditions and without external heat supply. The nitrogen oxide content in the exhaust gas flow during the cold start phase is reduced by up to 67%.
Es gelingt so, auch bei hoch motorisierten Fahrzeugen die NOx-Emissionen substantiell zu senken. Die NOx-Aufnahmeraten sind reproduzierbar hoch, während der aufgrund des hohen Durchflusses über das Adsorbermodul auf tretende Druckverlust durch große Partikeldurchmesser der Alumosilikatpar- tikel gering gehalten werden kann. Weitere Vorteile und Ausgestaltungen der Erfindung ergeben sich aus der Beschreibung und den beiliegenden Zeich nungen. In this way, it is possible to substantially reduce NOx emissions even in high-powered vehicles. The NOx absorption rates are reproducibly high, while the pressure loss that occurs due to the high flow through the adsorber module can be kept low by the large particle diameter of the aluminosilicate particles. Further advantages and refinements of the invention result from the description and the accompanying drawings.
Es versteht sich, dass die voranstehend genannten und die nachstehend noch zu erläuternden Merkmale nicht nur in der jeweils angegebenen Kom bination, sondern auch in anderen Kombinationen oder in Alleinstellung ver wendbar sind, ohne den Rahmen der vorliegenden Erfindung zu verlassen. It goes without saying that the features mentioned above and those still to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.
Die Erfindung ist anhand von Ausführungsformen in den nachfolgenden Bei- spielen und den beigefügten Zeichnungen exemplarisch dargestellt und wird unter Bezugnahme auf die Zeichnungen weiter beschrieben. Es zeigt: Figur 1 ein Beispieldiagramm der Gehalte an Stickoxiden und Sauerstoff in einem ein erfindungsgemäßes Abgasmodul verlassenden Ab gasstrom über die Zeit; Figur 2 ein Beispieldiagramm der Gehalte an Stickoxiden und Sauerstoff in einem Abgasstrom am Eingang und am Ausgang eines erfin dungsgemäßen Abgasmoduls über die Zeit. The invention is illustrated by way of example based on embodiments in the following examples and the accompanying drawings and is further described with reference to the drawings. It shows: FIG. 1 shows an example diagram of the contents of nitrogen oxides and oxygen in an exhaust gas flow leaving an exhaust gas module according to the invention over time; FIG. 2 shows an example diagram of the contents of nitrogen oxides and oxygen in an exhaust gas stream at the inlet and at the outlet of an exhaust gas module according to the invention over time.
Beispiel 1 In einem Laborversuch wurden in einer zylindrischen PlastikkartuscheExample 1 In a laboratory test, in a cylindrical plastic cartridge
(Durchmesser 1 ,6 cm) 25 mL Zeolithpartikel (Schüttdichte 700 kg/m3) vorge geben. Nach Einstellung eines Volumenflusses von 4,7 L/min eines 1.500 ppm NO enthaltendem N2-Stroms durch die Kartusche wurde zusätz lich ein Sauerstoffgasstrom von 1,3 L/min O2 (99% Reinheit) in die Kartusche dosiert, so dass sich insgesamt ein Volumenstrom von 6 L/min durch die Kartusche ergab. Mit einem testo 340 Abgasanalysegerät (Testo SE & Co. KGaA, 79822 Titisee-Neustadt) wurde der Verlauf der Gehalte an NO, NO2, NOx sowie Sauerstoff im Abgasstrom am Ausgang der Kartusche über einen Zeitraum von 900 s aufgenommen und protokolliert. (Diameter 1.6 cm) 25 mL zeolite particles (bulk density 700 kg/m 3 ) given. After setting a volume flow of 4.7 L/min of an N2 flow containing 1,500 ppm NO through the cartridge, an additional oxygen gas flow of 1.3 L/min O2 (99% purity) was metered into the cartridge, so that an overall flow rate of 6 L/min through the cartridge. Using a testo 340 flue gas analyzer (Testo SE & Co. KGaA, 79822 Titisee-Neustadt), the NO, NO2, NOx and oxygen levels in the flue gas flow at the outlet of the cartridge were recorded and recorded over a period of 900 s.
Figur 1 zeigt die Ergebnisse der Messung. Es wurde eine maximale NOx- Aufnahmerate von 67% bestimmt; dies entspricht einer Raumzeitausbeute von 14.400 Ir1. Ohne Zudosierung von Sauerstoff wird praktisch kein NO adsorbiert. Figure 1 shows the results of the measurement. A maximum NOx uptake rate of 67% was determined; this corresponds to a space-time yield of 14,400 Ir 1 . Virtually no NO is adsorbed without the addition of oxygen.
Beispiel 2 example 2
Eine Ausführungsform des erfindungsgemäßen Abgasmoduls wurde in ei nem Feldversuch mit einem hoch motorisierten (Motorleistung >350 PS)An embodiment of the exhaust module according to the invention was in egg nem field test with a highly motorized (engine power> 350 hp)
PKW unter realen Bedingungen getestet. Hierfür wurden 2,2 L des Adsor- bermaterials aus Beispiel 1 in eine zylinderförmige Kartusche (16 cm Durch messer) platziert und mit 1,5 L Silicagel als Feuchteschutz überdeckt. Das Rohemissionsgas der VKM des PKW wurde über 2 Verjüngungen am Dop pelauspuff gebündelt und über 2 Eingänge ins obere Segment der unten durchperforierten Kartusche eingeleitet. Es wurden zudem während der Kalt- startphase (0 s bis 120 s nach Motorstart) 50-100 L/min reiner Sauerstoff aus einer Druckgasflasche kontinuierlich eingeleitet. Mit einem testo 340 Ab gasanalysegerät (Testo SE & Co. KGaA, 79822 Titisee-Neustadt) wurde der Verlauf von Temperatur, NO und NO2 sowie NOx am Eingang und am Aus- gang der Kartusche aufgenommen und protokolliert. Der Kaltstart erfolgte nach Kalibrierung der Sensoren, die Messwerte wurden unter mobilen Kalt startbedingungen aufgenommen. Damit wurden reale Bedingungen nachge stellt, man kann auch von RDE ("real drive emissions") sprechen. Figur 2 zeigt den NOx-Gehalt des Abgasstroms und am Ausgang des erfin dungsgemäßen Abgasmoduls über die Zeit während der Kaltstartphase (0 s bis 130 s nach Motorstart). Die NOx-Aufnahmeraten liegen trotz hoher Moto risierung (> 350 PS) und hohen Volumenausstößen von mindestens 60 m3/h bei ca. 48%, die Raumzeitausbeuten sind hoch und liegen im Bereich von mindestens 30.000 h 1. Car tested under real conditions. For this purpose, 2.2 L of the adsorber material from Example 1 were placed in a cylindrical cartridge (16 cm in diameter) and covered with 1.5 L of silica gel to protect against moisture. The raw emission gas of the car's ICE was bundled via 2 tapers on the double exhaust and introduced via 2 inlets into the upper segment of the cartridge, which was perforated at the bottom. In addition, during the cold start-up phase (0 s to 120 s after engine start) 50-100 L/min of pure oxygen from a compressed gas bottle are continuously introduced. With a testo 340 flue gas analyzer (Testo SE & Co. KGaA, 79822 Titisee-Neustadt), the course of temperature, NO and NO2 as well as NOx at the inlet and outlet of the cartridge was recorded and logged. The cold start took place after the sensors were calibrated, the measured values were recorded under mobile cold start conditions. Real conditions were thus simulated; one can also speak of RDE ("real drive emissions"). FIG. 2 shows the NOx content of the exhaust gas stream and at the outlet of the exhaust gas module according to the invention over time during the cold start phase (0 s to 130 s after engine start). The NOx absorption rates are in spite of high motorization (> 350 hp) and high volume emissions of at least 60 m 3 / h at about 48%, the space-time yields are high and are in the range of at least 30,000 h 1 .

Claims

PATENTANSPRÜCHE: PATENT CLAIMS:
1. Verfahren zur Entfernung von NO und/oder NOx aus einem Abgasstrom eines Verbrennungsmotors während der Kaltstartphase, bei dem der Abgasstrom und ein Sauerstoff enthaltender Gasstrom gleichzeitig durch ein Alumosilikatpartikel enthaltendes Adsorbermodul geleitet wird, und NO und/oder NOx durch den Sauerstoff oxidiert und an den Alumosilikatpartikeln adsorbiert werden. 1. A method for removing NO and/or NOx from an exhaust gas flow of an internal combustion engine during the cold start phase, in which the exhaust gas flow and an oxygen-containing gas flow are passed simultaneously through an adsorber module containing aluminosilicate particles, and NO and/or NOx are oxidized by the oxygen and on be adsorbed on the aluminosilicate particles.
2. Verfahren nach Anspruch 1 , welches in einem Temperaturbereich von -40°C bis 40°C Außentemperatur und bei einer Durchflussrate von min destens 60 m3/h Abgas durchgeführt wird und eine Raumzeitausbeute von mindestens 30.000 Ir1 aufweist. 2. The process according to claim 1, which is carried out in a temperature range from -40°C to 40°C outside temperature and at a flow rate of at least 60 m 3 /h exhaust gas and has a space-time yield of at least 30,000 Ir 1 .
3. Verfahren nach Anspruch 1 oder 2, bei dem das Schüttvolumen der im Adsorbermodul enthaltenen Alumosilikatpartikel von 1 bis 3 L beträgt. 3. The method according to claim 1 or 2, wherein the bulk volume of the aluminosilicate particles contained in the adsorber module is from 1 to 3 l.
4. Verfahren nach einem der Ansprüche 1 bis 3, bei dem die Schüttdichte der Alumosilikatpartikel im Bereich von 650 kg/m3 bis 750 kg/m3 beträgt 4. The method as claimed in any of claims 1 to 3, in which the bulk density of the aluminosilicate particles is in the range from 650 kg/m 3 to 750 kg/m 3
5. Verfahren nach einem der voranstehenden Ansprüche, bei dem der mittlere Teilchendurchmesser der Alumosilikatpartikel im Bereich von 0,1 mm bis 0,7 mm beträgt. 5. The method according to any one of the preceding claims, in which the mean particle diameter of the aluminosilicate particles is in the range from 0.1 mm to 0.7 mm.
6. Verfahren nach einem der voranstehenden Ansprüche, bei dem die Alumosilikatpartikel regeneriert werden, indem ein heißer Abgasstrom durch das Adsorbermodul geleitet wird. 6. The method according to any one of the preceding claims, in which the aluminosilicate particles are regenerated by a hot exhaust gas flow is passed through the adsorber module.
7. Verfahren nach einem der voranstehenden Ansprüche, bei dem der das Adsorbermodul verlassende Abgasstrom einem SCR-Modul zugeleitet wird. 7. The method according to any one of the preceding claims, wherein the exhaust gas flow leaving the adsorber module is fed to an SCR module.
8. Vorrichtung zur Entfernung von NO und/oder NOx aus einem Ab gasstrom eines Verbrennungsmotors während der Kaltstartphase, um fassend a) ein in einem Abgasstrang des Verbrennungsmotors angeord- netes, Alumosilikatpartikel enthaltendes Adsorbermodul; b) ein Modul zur selektiven katalytischen Reduktion von Stickoxi den (SCR-Modul); und c) Mittel zur Dosierung eines Sauerstoff enthaltenden Zusatzga ses in das Adsorbermodul. 8. Device for removing NO and/or NOx from an exhaust gas stream of an internal combustion engine during the cold start phase, comprising a) an adsorber module containing aluminosilicate particles arranged in an exhaust system of the internal combustion engine; b) a module for the selective catalytic reduction of nitrogen oxides (SCR module); and c) means for metering an oxygen-containing supplementary gas into the adsorber module.
9. Vorrichtung nach Anspruch 8, worin das Adsorbermodul dem SCR- Modul im Abgasstrang vorgeschaltet ist. 9. The device according to claim 8, wherein the adsorber module is connected upstream of the SCR module in the exhaust line.
10. Vorrichtung nach Anspruch 8 oder 9, worin der Abgasstrang Mittel um- fasst, die einen Abgasstrom wahlweise durch das Adsorbermodul oder an diesem vorbei leiten. 10. The device as claimed in claim 8 or 9, wherein the exhaust line comprises means which selectively direct an exhaust gas flow through the adsorber module or past it.
PCT/EP2022/062925 2021-05-20 2022-05-12 Cold-start exhaust-gas emission control WO2022243159A1 (en)

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US20170226917A1 (en) * 2016-02-04 2017-08-10 Umicore Ag & Co. Kg System and method for cleaning exhaust gas while avoiding nitrous oxide
DE102016219301A1 (en) 2016-10-05 2018-04-05 Audi Ag Method and device for exhaust gas purification
WO2019072973A1 (en) 2017-10-12 2019-04-18 Krajete GmbH Method for reducing the nitrogen oxide(s) and/or co content in a combustion and/or exhaust gas
WO2020069549A1 (en) * 2018-10-05 2020-04-09 Avl List Gmbh Petrol engine arrangement and method comprising an nsc system

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5771684A (en) * 1994-08-02 1998-06-30 Corning Incorporated Gas treatment systems
DE69618357T2 (en) * 1995-01-27 2002-07-11 Toyota Chuo Kenkyusho Aichi Kk Processes for the purification of combustion gases
DE19816276A1 (en) * 1998-04-11 1999-10-14 Audi Ag Method for operating an internal combustion engine
DE60130406T2 (en) 2000-07-05 2008-06-12 Ecocat Oy System and method for purifying exhaust gases
US20170226917A1 (en) * 2016-02-04 2017-08-10 Umicore Ag & Co. Kg System and method for cleaning exhaust gas while avoiding nitrous oxide
DE102016219301A1 (en) 2016-10-05 2018-04-05 Audi Ag Method and device for exhaust gas purification
WO2019072973A1 (en) 2017-10-12 2019-04-18 Krajete GmbH Method for reducing the nitrogen oxide(s) and/or co content in a combustion and/or exhaust gas
WO2020069549A1 (en) * 2018-10-05 2020-04-09 Avl List Gmbh Petrol engine arrangement and method comprising an nsc system

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