WO2023102590A1 - Combustion engine system comprising an ammonia combustion engine and connected exhaust gas cleaning system and operating method for same - Google Patents

Combustion engine system comprising an ammonia combustion engine and connected exhaust gas cleaning system and operating method for same Download PDF

Info

Publication number
WO2023102590A1
WO2023102590A1 PCT/AT2022/060433 AT2022060433W WO2023102590A1 WO 2023102590 A1 WO2023102590 A1 WO 2023102590A1 AT 2022060433 W AT2022060433 W AT 2022060433W WO 2023102590 A1 WO2023102590 A1 WO 2023102590A1
Authority
WO
WIPO (PCT)
Prior art keywords
exhaust gas
combustion engine
catalytic converter
internal combustion
scr catalytic
Prior art date
Application number
PCT/AT2022/060433
Other languages
German (de)
French (fr)
Inventor
Hannes NOLL
Philipp MICHELITSCH
Original Assignee
Avl List Gmbh
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 Avl List Gmbh filed Critical Avl List Gmbh
Priority to CN202280070931.1A priority Critical patent/CN118140041A/en
Priority to DE112022003897.7T priority patent/DE112022003897A5/en
Publication of WO2023102590A1 publication Critical patent/WO2023102590A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B43/00—Engines characterised by operating on gaseous fuels; Plants including such engines
    • F02B43/10—Engines or plants characterised by use of other specific gases, e.g. acetylene, oxyhydrogen
    • 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
    • F01N3/02—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
    • 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
    • F01N3/103—Oxidation catalysts for HC and CO only
    • 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]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
    • F02D19/0639—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels
    • F02D19/0642—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions
    • F02D19/0644—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions the gaseous fuel being hydrogen, ammonia or carbon monoxide
    • 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
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B43/00—Engines characterised by operating on gaseous fuels; Plants including such engines
    • F02B43/10—Engines or plants characterised by use of other specific gases, e.g. acetylene, oxyhydrogen
    • F02B2043/103—Natural gas, e.g. methane or LNG used as a fuel
    • 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

  • Ammonia (NH3) as a fuel for internal combustion engines has the advantage of not causing any CO2 emissions.
  • the combustion of NH3 produces nitrogen oxides (NOx).
  • NOx nitrogen oxides
  • residues of unburned NH3 can be contained in the exhaust gas from internal combustion engines operated with NH3. Both NOx and NH3 are pollutants that have to be removed from the exhaust gas at least to a large extent.
  • the internal combustion engine system comprises an internal combustion engine operated at least predominantly with ammonia as the fuel and an exhaust gas cleaning system connected to the internal combustion engine for cleaning the exhaust gas emitted by the internal combustion engine.
  • the emission control system has a first SCR catalytic converter for reducing NOx contained in the exhaust gas and, according to the invention, a further, second SCR catalytic converter for reducing NOx contained in the exhaust gas, which is attached to the first SCR catalytic converter is upstream in terms of flow.
  • the fact that two SCR catalytic converters arranged separately from one another are provided means that NOx can be removed from the exhaust gas in an improved manner.
  • the second SCR catalytic converter which is preferably installed close to the engine, is quickly ready for operation. If the catalytic effectiveness drops as a result of excessive heating, the first SCR catalytic converter, which is preferably arranged in the underbody area of the corresponding motor vehicle, can take over the NOx removal as a result of its meanwhile starting to heat up.
  • the internal combustion engine system can be installed in a car, a commercial vehicle, a tractor, a ship or in a locomotive.
  • the NH3 fuel that is predominantly used to operate the internal combustion engine can be mixed with the combustion air in an intake manifold or injected directly into a combustion chamber in liquid or gaseous form.
  • the NH3 fuel is taken from a fuel tank in which it is at least predominantly in liquid form.
  • an ignition promoter such as diesel, ethanol, diethyl ether or another suitable substance can be provided for the internal combustion engine.
  • the amount of the ignition promoter is comparatively small compared to the amount of the actual fuel NH3. Preferably it is less than 20% or less than 10% of the NHs amount.
  • SCR catalytic converters these are to be understood as meaning catalytic converters capable of catalyzing a reduction of NOx to nitrogen (N2) using NH3 as the reducing agent, even in the presence of an excess of oxygen.
  • the exhaust gas cleaning system has precisely one injector for adding NH3 to the exhaust gas, the injector for adding NH3 to the exhaust gas being designed on the inlet side of the first SCR catalytic converter.
  • Said NHs injector is thus the only NHs injector of the emission control system. It is preferably arranged directly in front of the exhaust gas inlet side of the first SCR catalytic converter in the exhaust gas cleaning system.
  • the injector can inject the NOx reducing agent NH3 in liquid or gaseous form into the exhaust gas. It is preferably taken from the fuel tank.
  • the second, located further upstream The SCR catalytic converter receives the NOx reducing agent NH3 with the supplied exhaust gas, which contains it in the form of NH3 slip from the internal combustion engine due to incomplete combustion.
  • the second SCR catalytic converter can thus be referred to as a passive SCR catalytic converter, which brings about a reduction in NOx without the addition of a reducing agent from the outside.
  • the amount of NHs present in the form of NHs slip in the exhaust gas is less than the amount of NOx emitted by the engine. Downstream of the second SCR catalytic converter, the exhaust gas therefore still contains more or less high levels of NOx. These are then reduced at the downstream first SCR catalytic converter by means of NH3 supplied from outside. In this way, very low NOx tailpipe emissions can be achieved.
  • the exhaust gas purification system has a particle filter for filtering out particles contained in the exhaust gas, the particle filter being arranged upstream of the first SCR catalytic converter and downstream of the second SCR catalytic converter.
  • the particle filter is preferably arranged upstream of the NHs addition point formed by the NHs injector in the exhaust system.
  • the exhaust gas purification system has an oxidation catalytic converter which is arranged in terms of flow between the second SCR catalytic converter and the particle filter.
  • the NO2 content of the NOx contained in the exhaust gas can be increased by the oxidation catalytic converter, which improves the NOx reduction in the first SCR catalytic converter.
  • the particle filter can also be designed with an oxidation-catalytic coating.
  • the internal combustion engine is designed as a compression-ignited internal combustion engine. Therefore, ignition means such as spark plugs for igniting the fuel in its combustion chambers are omitted for the internal combustion engine.
  • NOx contained in the exhaust gas is reduced at a first SCR catalytic converter by means of NH3 added to the exhaust gas through an injector , wherein NOx contained in the exhaust gas is additionally reduced at a second SCR catalytic converter upstream of the first SCR catalytic converter by means of NH3 emitted by the internal combustion engine.
  • the second SCR catalytic converter acts as the first NOx cleaning stage, in which the NOx contained in the exhaust gas is reduced by means of the NHs component in the exhaust gas, which is present in the form of an NHs slip and is provided by the combustion engine.
  • the second NOx purification stage is formed by the downstream first SCR catalyst. In this, the NOx remaining in the exhaust gas is reduced by NH3 added to the exhaust gas from outside by means of an injector.
  • particles contained in the exhaust gas are filtered out of the exhaust gas by means of a particle filter arranged in terms of flow between the first SCR catalytic converter and the second SCR catalytic converter.
  • the internal combustion engine is operated at least predominantly with excess air. This enables fuel combustion with high mechanical efficiency.
  • the invention is explained in more detail below with reference to a drawing and associated examples. The only figure shows an advantageous embodiment of the internal combustion engine system according to the invention.
  • the internal combustion engine system shown only as an example and schematically in the figure comprises an internal combustion engine 1 and an exhaust gas cleaning system 2 connected to it.
  • the combustion air required for fuel combustion is supplied to the internal combustion engine 1 via an air supply line 3, which is fed into an intake manifold 4 of the internal combustion engine 1 downstream of a arranged turbocharger compressor 5 opens.
  • the internal combustion engine 1 is designed as an internal combustion engine operated predominantly with excess air according to the diesel principle, ie as a compression igniter of the reciprocating piston type.
  • NH3 is used as the fuel, which in the present case is taken from a tank 7 and is supplied to the combustion air on the inlet side of the intake manifold 4 via a first NHs supply line 6 .
  • a feed pump used for this purpose and a control valve for controlling the amount of NHs supplied are not shown separately.
  • NH3 can also be fed directly to the intake manifold 4 .
  • NHs direct injection into the individual combustion chambers of the internal combustion engine 1, which are also not shown separately here.
  • a pilot or pre-injection of a substance that acts as an ignition promoter such as diesel fuel, ethanol, dimethyl ether, acetone or another be provided flammable substance.
  • Corresponding supply means are not shown for reasons of clarity.
  • the amount of ignition promoter used is relatively small compared to the amount of the actual fuel NH3 and is preferably less than 10%, less than 5% or less than 2%.
  • Exhaust gas produced during fuel combustion is discharged from the internal combustion engine 1 via an exhaust manifold 8 and an exhaust pipe 9 connected thereto and fed to the exhaust gas cleaning system 2 .
  • a turbocharger turbine arranged in the exhaust gas line 9 is driven, which in turn drives the turbocharger compressor 5 via a shaft (not shown).
  • the exhaust gas purification system 2 has the following cleaning-active components arranged one behind the other in the exhaust gas line 9 viewed in the direction of the exhaust gas flow.
  • a nitrogen oxide reduction catalytic converter referred to here as the second SCR catalytic converter 11, an oxidation catalytic converter 12, a particle filter 13 and a further nitrogen oxide reduction catalytic converter, referred to here as the first SCR catalytic converter 14.
  • the catalytic converters 11, 12 and 14 are preferably in the form of, in particular, ceramic honeycomb bodies with continuous, parallel channels.
  • the duct walls that come into contact with the exhaust gas are coated with the respective specific catalytically active substance.
  • the SCR catalytic converters 11, 14 can, for example, be a zeolite exchanged with iron and/or copper as the catalytically active substance.
  • the catalytically active substances enable a selective reduction of NOx contained in the exhaust gas with the NH3 used here as a reducing agent, even under oxidizing conditions.
  • the catalytically active substance of the oxidation catalyst can be a finely dispersed metal from the platinum group, such as platinum, palladium and/or rhodium.
  • the particle filter 13 is preferably designed as a honeycomb body through which air flows through the wall, with parallel channels that are alternately closed on the inlet and outlet sides.
  • the second SCR catalytic converter 11 is designed according to the invention as a so-called passive SCR catalytic converter.
  • the reducing agent NH3 required for NOx reduction is not supplied to the second SCR catalytic converter 11 from outside by a separate supply device.
  • NH3 emitted by the internal combustion engine 1 serves as a reducing agent for selective NOx reduction.
  • This so-called NHs slip of internal combustion engine 1 is the result of incomplete combustion of the fuel NH3 in internal combustion engine 1.
  • the source of the reducing agent NH3 for selective catalytic NOx reduction in the second SCR catalytic converter is therefore exclusively the NHs slip of internal combustion engine 1.
  • residual amounts of NOx or NH3 can be present in the exhaust gas flowing out of the second SCR catalytic converter 11 . These are introduced into the downstream oxidation catalytic converter 12 with the exhaust gas flow. If residual amounts of NOx are contained in the exhaust gas, the NOx component nitrogen monoxide (NO) is at least partially oxidized there to form nitrogen dioxide (NO2) with the oxygen contained in the exhaust gas of the lean-burn internal combustion engine 1 .
  • NO2 nitrogen dioxide
  • the aim here is an NO/NO2 ratio of approximately 1:1, which improves or facilitates the catalytic NOx reduction in the first SCR catalytic converter 14 arranged further downstream.
  • this NH3 is at least partially oxidized to form NO or NO2.
  • the exhaust gas flowing out of the oxidation catalytic converter 12 contains NOx, which is at least largely reduced in the first SCR catalytic converter 14 arranged further downstream.
  • the first SCR catalytic converter 14 receives the reducing agent NH3 required for selective NOx reduction by adding it via an upstream injector 15. This is connected to the tank 7 via a second NHs supply line 16. A feed pump that is preferably provided is not shown separately. NH3 can be taken from the tank 7 in liquid form or in gaseous form and injected into the exhaust gas by the injector 15 on the inlet side of the first SCR catalytic converter 14 .
  • the SCR catalytic converter 14 When liquid NH3 is added, it evaporates in the hot exhaust gas, which is why the SCR catalytic converter 14 is supplied with NH3 at least predominantly in gaseous form. This ensures an even NH3 distribution in the flue gas, which is why a mixer is not required. Since, in contrast to the first SCR catalytic converter 14, the second SCR catalytic converter 11 does not cover its NOx reducing agent requirement by adding it to the exhaust gas through an injector, but rather by NHs slip from the internal combustion engine 1, no further NOx reducing agent adding device is required in addition to the injector 15 for the emission control system 2. The injector 7 is therefore the only NOx reducing agent addition device of the emission control system 2.
  • a first NOx sensor 17 for detecting the NOx content in the exhaust gas is provided on the outlet side of the oxidation catalytic converter 12 or between the oxidation catalytic converter 12 and the particle filter 13 . This enables the NOx content of the exhaust gas flowing into the first SCR catalytic converter 14 to be determined. From the determined NOx content of the exhaust gas, the NHs requirement for the reduction of NOx contained in the exhaust gas in the first SCR catalytic converter 14 can in turn be determined and the injector 15 can be controlled accordingly. If the oxidation catalytic converter 12 and particle filter 13 are combined to form an integral common component, the first NOx sensor 17 is preferably arranged on the output side of this component.
  • a second NOx sensor 18 is arranged on the output side of the first SCR catalytic converter 14 and makes it possible to determine any NOx that may have slipped through the first SCR catalytic converter 14 . In this case, the enrichment of the exhaust gas caused by the injector 15 with the reducing agent NH3 can be adjusted.
  • NOx sensors can also be designed as combined NOx/NH3 sensors.
  • the corresponding NHs contents can also be determined, which can improve the accuracy of the NHs metering if necessary.
  • the internal combustion engine system enables an extremely environmentally friendly operation of a corresponding vehicle. Not only emissions of climate-damaging CO2 are at least largely avoided, but also at least largely emissions of hydrocarbons NOx, NH3 and particles. reference number

Landscapes

  • 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)
  • Materials Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

The invention relates to a combustion engine system comprising a combustion engine (1) operating at least predominantly with ammonia as the fuel and with a connected exhaust gas cleaning system (2) for cleaning an exhaust gas output by the combustion engine (1), wherein the exhaust gas cleaning system (2) has a first SCR catalyst (14) for reducing nitrogen oxides in the exhaust gas. According to the invention, the exhaust gas cleaning system (2) also has a second SCR catalyst (11) for reducing nitrogen oxides in the exhaust gas, which is connected upstream of the first SCR catalyst (14). For the operating method according to the invention for the combustion engine system, exhaust gas from a combustion engine (1) operating at least predominantly with ammonia as the fuel is cleaned, wherein nitrogen oxides in the exhaust gas are reduced at an SCR catalyst (14) by means of ammonia added to the exhaust gas via an injector (15), wherein nitrogen oxides in the exhaust gas are also reduced at a second SCR catalyst (11) connected upstream of the first SCR catalyst (14) by means of ammonia output by the combustion engine (1).

Description

Verbrennungsmotorsystem mit einem Ammoniak-Verbrennungsmotor und daran angeschlossener Abgasreinigungsanlage und Betriebsverfahren hierfür Internal combustion engine system with an ammonia internal combustion engine and exhaust gas purification system connected thereto and operating method therefor
Ammoniak (NH3) als Kraftstoff für Verbrennungsmotoren besitzt den Vorteil, keinerlei CO2-Emissionen zu verursachen. Jedoch entstehen bei der Verbrennung von NH3 Stickoxide (NOx). Außerdem können im Abgas von mit NH3 betriebenen Verbrennungsmotoren Reste von unverbranntem NH3 enthalten sein. Sowohl NOx als auch NH3 sind Schadstoffe, welche es aus dem Abgas zumindest weitgehend zu entfernen gilt. Ammonia (NH3) as a fuel for internal combustion engines has the advantage of not causing any CO2 emissions. However, the combustion of NH3 produces nitrogen oxides (NOx). In addition, residues of unburned NH3 can be contained in the exhaust gas from internal combustion engines operated with NH3. Both NOx and NH3 are pollutants that have to be removed from the exhaust gas at least to a large extent.
Aus der US 2010/0019506 A1 ist es bekannt, zur Abgasreinigung bei einem mit NH3 betriebenen Verbrennungsmotor einen SCR-Katalysator einzusetzen, der im Abgas enthaltenes NOx mit infolge unvollständiger NHs-Verbrennung im Abgas enthaltenem NH3 (NHs-Schlupf) reduzieren kann. Hierfür wird der Verbrennungsmotor so betrieben, dass ein ausreichend hoher NHs-Schlupf entsteht. Jedoch kann es einerseits schwierig sein, den NHs-Schlupf passend einzustellen um sowohl NOx- als auch NHs-Emissionen zu vermeiden. Andererseits ist die absichtliche Erzeugung eines NHs-Schlupfes mit einem unvorteilhaften Kraftstoff-Mehrverbrauch verbunden. From US 2010/0019506 A1 it is known to use an SCR catalytic converter for exhaust gas purification in an internal combustion engine operated with NH3, which can reduce NOx contained in the exhaust gas with NH3 contained in the exhaust gas as a result of incomplete NHs combustion (NHs slip). For this purpose, the internal combustion engine is operated in such a way that a sufficiently high NHs slip occurs. However, on the one hand it can be difficult to adjust the NHs slip appropriately to avoid both NOx and NHs emissions. On the other hand, the intentional generation of an NHs slip is associated with an unfavorable increase in fuel consumption.
Aufgabe der vorliegenden Erfindung ist es, ein Verbrennungsmotorsystem mit einem Ammoniak-Verbrennungsmotor und daran angeschlossener Abgasreinigungsanlage und ein Betriebsverfahren hierfür bereitzustellen, durch welche eine verbesserte Abgasreinigung ermöglicht ist. Diese Aufgabe wird durch ein Verbrennungsmotorsystem mit den Merkmalen des Anspruchs 1 und ein Betriebsverfahren mit den Merkmalen des Anspruchs 6 gelöst. Vorteilhafte Ausbildungen sind in den jeweiligen Unteransprüchen angegeben. It is the object of the present invention to provide an internal combustion engine system with an ammonia internal combustion engine and an exhaust gas cleaning system connected thereto and an operating method for this, by means of which improved exhaust gas cleaning is made possible. This object is achieved by an internal combustion engine system having the features of claim 1 and an operating method having the features of claim 6. Advantageous developments are specified in the respective dependent claims.
Das erfindungsgemäße Verbrennungsmotorsystem umfasst einen zumindest überwiegend mit Ammoniak als Kraftstoff betriebenen Verbrennungsmotor sowie eine an den Verbrennungsmotor angeschlossene Abgasreinigungsanlage zur Reinigung des vom Verbrennungsmotor abgegebenen Abgases auf. Dabei weist die Abgasreinigungsanlage einen ersten SCR-Katalysator zur Reduktion von im Abgas enthaltenem NOx auf, sowie erfindungsgemäß einen weiteren, zweiten SCR-Katalysator zur Reduktion von im Abgas enthaltenem NOx auf, der dem ersten SCR-Katalysator strömungstechnisch vorgeschaltet ist. Dadurch, dass zwei voneinander getrennt angeordnete SCR-Katalysatoren vorgesehen sind, kann eine Entfernung von NOx aus dem Abgas verbessert erfolgen. Infolge eines natürlicherweise vorhandenen Temperaturgefälles entlang des Abgasströmungswegs ist der zweite, vorzugsweise motornah verbaute SCR-Katalysator rasch betriebsbereit. Sinkt die katalytische Wirksamkeit infolge zu starker Erhitzung ab, so kann der, vorzugsweise im Unterbodenbereich des entsprechenden Kraftfahrzeugs angeordnete, erste SCR- Katalysator infolge seiner inzwischen einsetzenden Erwärmung die NOx-Entfernung übernehmen. Das Verbrennungsmotorsystem kann in einem PKW, einem Nfz, einem Traktor, einem Schiff oder in einer Lokomotive verbaut sein. The internal combustion engine system according to the invention comprises an internal combustion engine operated at least predominantly with ammonia as the fuel and an exhaust gas cleaning system connected to the internal combustion engine for cleaning the exhaust gas emitted by the internal combustion engine. The emission control system has a first SCR catalytic converter for reducing NOx contained in the exhaust gas and, according to the invention, a further, second SCR catalytic converter for reducing NOx contained in the exhaust gas, which is attached to the first SCR catalytic converter is upstream in terms of flow. The fact that two SCR catalytic converters arranged separately from one another are provided means that NOx can be removed from the exhaust gas in an improved manner. As a result of a naturally occurring temperature gradient along the exhaust gas flow path, the second SCR catalytic converter, which is preferably installed close to the engine, is quickly ready for operation. If the catalytic effectiveness drops as a result of excessive heating, the first SCR catalytic converter, which is preferably arranged in the underbody area of the corresponding motor vehicle, can take over the NOx removal as a result of its meanwhile starting to heat up. The internal combustion engine system can be installed in a car, a commercial vehicle, a tractor, a ship or in a locomotive.
Der zum Betrieb des Verbrennungsmotors überwiegend eingesetzte Kraftstoff NH3 kann der Verbrennungsluft in einem Saugrohr zugemischt werden oder auch direkt in einen Brennraum in flüssiger Form oder gasförmig eingespritzt werden. Der Kraftstoff NH3 wird dabei einem Kraftstoffvorratsbehälter entnommen, in dem er zumindest überwiegend in flüssiger Form vorliegt. Zur Verbesserung der NHs-Entflammung kann die zusätzliche Zugabe bzw. Einspritzung eines Zündpromotors wie Diesel, Äthanol, Diäthyläther oder eines anderen geeigneten Stoffes zum Verbrennungsmotor vorgesehen sein. Die Menge des Zündpromotors ist dabei im Vergleich zur Menge des eigentlichen Kraftstoffs NH3 jedoch vergleichsweise gering. Vorzugsweise beträgt sie weniger als 20 % oder weniger als 10 % der NHs-Menge. The NH3 fuel that is predominantly used to operate the internal combustion engine can be mixed with the combustion air in an intake manifold or injected directly into a combustion chamber in liquid or gaseous form. The NH3 fuel is taken from a fuel tank in which it is at least predominantly in liquid form. To improve the NHs ignition, the additional addition or injection of an ignition promoter such as diesel, ethanol, diethyl ether or another suitable substance can be provided for the internal combustion engine. However, the amount of the ignition promoter is comparatively small compared to the amount of the actual fuel NH3. Preferably it is less than 20% or less than 10% of the NHs amount.
Was die SCR-Katalysatoren betrifft, so sind darunter Katalysatoren zu verstehen, die in der Lage sind, eine Reduktion von NOx zu Stickstoff (N2) mittels NH3 als Reduktionsmittel auch bei Vorliegen eines Sauerstoffüberschusses zu katalysieren. With regard to SCR catalytic converters, these are to be understood as meaning catalytic converters capable of catalyzing a reduction of NOx to nitrogen (N2) using NH3 as the reducing agent, even in the presence of an excess of oxygen.
In Ausgestaltung der Erfindung weist die Abgasreinigungsanlage genau einen Injektor zur Zugabe von NH3 zum Abgas auf, wobei der Injektor zur Zugabe von NH3 zum Abgas eingangsseitig des ersten SCR-Katalysators ausgebildet ist. Besagter NHs-lnjektor ist somit der einzige NHs-lnjektor der Abgasreinigungsanlage. Vorzugsweise ist er unmittelbar vor der Abgaseintrittsseite des ersten SCR-Katalysators in der Abgasreinigungsanlage angeordnet. Der Injektor kann das NOx-Reduktionsmittel NH3 in flüssiger Form oder gasförmig ins Abgas einspritzen. Vorzugsweise wird es dem Kraftstoffvorratsbehälter entnommen. Der zweite, weiter stromauf angeordnete SCR-Katalysator erhält das NOx-Reduktionsmittel NH3 mit dem zugeführten Abgas, in dem dieses in Form eines infolge unvollständiger Verbrennung vorhandenen NH3- Schlupfes aus dem Verbrennungsmotor enthalten ist. Der zweite SCR-Katalysator kann somit als passiver SCR-Katalysator bezeichnet werden, welcher eine NOx- Reduktion ohne eine Reduktionsmittelzugabe von außen bewirkt. In an embodiment of the invention, the exhaust gas cleaning system has precisely one injector for adding NH3 to the exhaust gas, the injector for adding NH3 to the exhaust gas being designed on the inlet side of the first SCR catalytic converter. Said NHs injector is thus the only NHs injector of the emission control system. It is preferably arranged directly in front of the exhaust gas inlet side of the first SCR catalytic converter in the exhaust gas cleaning system. The injector can inject the NOx reducing agent NH3 in liquid or gaseous form into the exhaust gas. It is preferably taken from the fuel tank. The second, located further upstream The SCR catalytic converter receives the NOx reducing agent NH3 with the supplied exhaust gas, which contains it in the form of NH3 slip from the internal combustion engine due to incomplete combustion. The second SCR catalytic converter can thus be referred to as a passive SCR catalytic converter, which brings about a reduction in NOx without the addition of a reducing agent from the outside.
Typischerweise ist die in Form des NHs-Schlupfes im Abgas vorhandene NHs-Menge geringer als die vom Motor emittierte NOx-Menge. Hinter dem zweiten SCR-Katalysator sind daher noch mehr oder weniger hohe NOx-Anteile im Abgas enthalten. Diese werden dann am stromabwärtigen ersten SCR-Katalysator mittels von außen zugeführtem NH3 reduziert. Auf diese Weise können sehr niedrige NOx-Endrohr- emissionen erzielt werden. Typically, the amount of NHs present in the form of NHs slip in the exhaust gas is less than the amount of NOx emitted by the engine. Downstream of the second SCR catalytic converter, the exhaust gas therefore still contains more or less high levels of NOx. These are then reduced at the downstream first SCR catalytic converter by means of NH3 supplied from outside. In this way, very low NOx tailpipe emissions can be achieved.
In weiterer Ausgestaltung der Erfindung weist die Abgasreinigungsanlage einen Partikelfilter zur Ausfilterung von im Abgas enthaltenen Partikeln auf, wobei der Partikelfilter strömungstechnisch vor dem ersten SCR-Katalysator und hinter dem zweiten SCR-Katalysator angeordnet ist. Vorzugsweise ist der Partikelfilter stromaufwärts von der durch den NHs-lnjektor gebildeten NHs-Zugabestelle im Abgasstrang angeordnet. Obschon durch die NHs-Verbrennung im Motor keine Rußpartikel erzeugt werden, können etwa durch Motoröladditive oder durch Verbrennung eines Zündpromotors verursachte Partikelemissionen entstehen. Die entsprechenden Partikel können durch den Partikelfilter aus dem Abgas entfernt werden. Da die Partikelemissionen typischerweise relativ gering sind, kann der Partikelfilter vergleichsweise klein ausfallen. Das Volumen des Partikelfilters kann deshalb weniger als 70%, weniger als 50 % oder sogar weniger als 30 % des Volumens des ersten bzw. des zweiten SCR-Katalysators betragen. In a further embodiment of the invention, the exhaust gas purification system has a particle filter for filtering out particles contained in the exhaust gas, the particle filter being arranged upstream of the first SCR catalytic converter and downstream of the second SCR catalytic converter. The particle filter is preferably arranged upstream of the NHs addition point formed by the NHs injector in the exhaust system. Although no soot particles are produced by NHs combustion in the engine, particulate emissions caused by engine oil additives or the combustion of an ignition promoter can occur. The corresponding particles can be removed from the exhaust gas by the particle filter. Since particle emissions are typically relatively low, the particle filter can be comparatively small. The volume of the particle filter can therefore be less than 70%, less than 50% or even less than 30% of the volume of the first or second SCR catalytic converter.
In weiterer Ausgestaltung der Erfindung weist die Abgasreinigungsanlage einen Oxidationskatalysator auf, der strömungstechnisch zwischen dem zweiten SCR-Katalysator und dem Partikelfilter angeordnet ist. Durch den Oxidationskatalysator kann der NO2-Anteil des im Abgas enthaltenen NOx angehoben werden, wodurch die NOx- Reduktion im ersten SCR-Katalysator verbessert wird. Alternativ zur Bereitstellung eines separaten Oxidationskatalysators zwischen zweitem SCR-Katalysator und Partikelfilter kann auch eine Ausführung des Partikelfilters mit einer oxidationskatalytischen Beschichtung vorgesehen sein. In a further embodiment of the invention, the exhaust gas purification system has an oxidation catalytic converter which is arranged in terms of flow between the second SCR catalytic converter and the particle filter. The NO2 content of the NOx contained in the exhaust gas can be increased by the oxidation catalytic converter, which improves the NOx reduction in the first SCR catalytic converter. As an alternative to providing a separate oxidation catalytic converter between the second SCR catalytic converter and the particle filter, the particle filter can also be designed with an oxidation-catalytic coating.
In weiterer Ausgestaltung der Erfindung ist der Verbrennungsmotor als kompressionsgezündeter Verbrennungsmotor ausgebildet. Es entfallen für den Verbrennungsmotor daher Zündmittel wie Zündkerzen zur Zündung des Kraftstoffs in seinen Brennräumen. In a further embodiment of the invention, the internal combustion engine is designed as a compression-ignited internal combustion engine. Therefore, ignition means such as spark plugs for igniting the fuel in its combustion chambers are omitted for the internal combustion engine.
Für das erfindungsgemäße Betriebsverfahren zum Betreiben eines Verbrennungsmotorsystems, bei welchem von einem zumindest überwiegend mit Ammoniak als Kraftstoff betriebenen Verbrennungsmotor abgegebenes Abgas gereinigt wird, ist vorgesehen, dass im Abgas enthaltenes NOx an einem ersten SCR-Katalysator mittels dem Abgas durch einen Injektor zugegebenem NH3 reduziert wird, wobei im Abgas enthaltenes NOx zusätzlich an einem dem ersten SCR-Katalysator strömungstechnisch vorgeschalteten zweiten SCR-Katalysator mittels vom Verbrennungsmotor abgegebenem NH3 reduziert wird. Es erfolgt somit eine zweistufige NOx- Reduktion. Dabei fungiert der zweite SCR-Katalysator als erste NOx-Reinigungs- stufe, in der im Abgas enthaltenes NOx mittels des in Form eines NHs-Schlupfes vorliegenden, vom Verbrennungsmotor bereitgestellten NHs-Anteils im Abgas reduziert wird. Die zweite NOx-Reinigungsstufe wird durch den stromabwärtigen ersten SCR-Katalysator gebildet. In diesem erfolgt eine Reduktion von im Abgas verbliebenem NOx durch von außen mittels eines Injektors dem Abgas zugesetztem NH3. For the operating method according to the invention for operating an internal combustion engine system, in which exhaust gas emitted by an internal combustion engine operated at least predominantly with ammonia as fuel is cleaned, it is provided that NOx contained in the exhaust gas is reduced at a first SCR catalytic converter by means of NH3 added to the exhaust gas through an injector , wherein NOx contained in the exhaust gas is additionally reduced at a second SCR catalytic converter upstream of the first SCR catalytic converter by means of NH3 emitted by the internal combustion engine. There is thus a two-stage NOx reduction. The second SCR catalytic converter acts as the first NOx cleaning stage, in which the NOx contained in the exhaust gas is reduced by means of the NHs component in the exhaust gas, which is present in the form of an NHs slip and is provided by the combustion engine. The second NOx purification stage is formed by the downstream first SCR catalyst. In this, the NOx remaining in the exhaust gas is reduced by NH3 added to the exhaust gas from outside by means of an injector.
In Ausgestaltung des erfindungsgemäßen Verfahrens werden im Abgas enthaltene Partikel mittels eines strömungstechnisch zwischen dem ersten SCR-Katalysator und dem zweiten SCR-Katalysator angeordneten Partikelfilter aus dem Abgas ausgefiltert. Es erfolgt somit eine umfassende Reinigung des Abgases, welche die Einhaltung strengster Grenzwerte für NOx- und Partikelemissionen ermöglicht. In an embodiment of the method according to the invention, particles contained in the exhaust gas are filtered out of the exhaust gas by means of a particle filter arranged in terms of flow between the first SCR catalytic converter and the second SCR catalytic converter. There is thus a comprehensive cleaning of the exhaust gas, which enables compliance with the strictest limit values for NOx and particle emissions.
In weiterer Ausgestaltung des Verfahrens ist vorgesehen, dass der Verbrennungsmotor zumindest überwiegend mit Luftüberschuss betrieben wird. Dies ermöglicht eine Kraftstoffverbrennung mit hohem mechanischen Wirkungsgrad. Nachfolgend wird die Erfindung anhand einer Zeichnung und zugehörigen Beispielen näher erläutert. Die einzige Figur zeigt dabei eine vorteilhafte Ausführungsform des erfindungsgemäßen Verbrennungsmotorsystems. In a further embodiment of the method, it is provided that the internal combustion engine is operated at least predominantly with excess air. This enables fuel combustion with high mechanical efficiency. The invention is explained in more detail below with reference to a drawing and associated examples. The only figure shows an advantageous embodiment of the internal combustion engine system according to the invention.
Das in der Figur lediglich beispielhaft und schematisch dargestellte Verbrennungsmotorsystem umfasst einen Verbrennungsmotor 1 und eine daran angeschlossene Abgasreinigungsanlage 2. Dem Verbrennungsmotor 1 wird seine zur Kraftstoffverbrennung erforderliche Verbrennungsluft über eine Luftzufuhrleitung 3 zugeführt, die in ein Saugrohr 4 des Verbrennungsmotors 1 stromab eines in der Luftzufuhrleitung 3 angeordneten Turboladerverdichters 5 einmündet. Der Verbrennungsmotor 1 ist als ein überwiegend mit Luftüberschuss betriebener Verbrennungsmotor nach dem Dieselprinzip, also als Kompressionszünder nach Hubkolbenbauart ausgebildet. Als Kraftstoff wird NH3 eingesetzt, welcher vorliegend einem Tank 7 entnommen wird und über eine erste NHs-Zufuhrleitung 6 der Verbrennungsluft eingangsseitig des Saugrohrs 4 zugeführt wird. Eine hierfür eingesetzte Förderpumpe und ein Regelventil zur Mengenregelung der zugeführten NHs-Menge sind dabei nicht gesondert dargestellt. NH3 kann natürlich auch direkt dem Saugrohr 4 zugeführt werden. Ebenfalls möglich ist eine NHs-Direkteinspritzung in die einzelnen, hier ebenfalls nicht gesondert dargestellten Brennräume des Verbrennungsmotors 1. Zur Verbesserung einer Zündung des Kraftstoffs NH3 kann eine Pilot- oder Voreinspritzung eines als Zündpromotors wirkenden Stoffes wie Dieselkraftstoff, Äthanol, Dimethyläther, Aceton oder ein anderer zündwilliger Stoff vorgesehen sein. Auf die Darstellung entsprechender Zufuhrmittel wurde aus Gründen der Übersichtlichkeit verzichtet. Die Menge des eingesetzten Zündpromotors ist dabei relativ gering gegenüber der Menge des eigentlichen Kraftstoffs NH3 und beträgt vorzugsweise weniger als 10 %, weniger als 5 % oder weniger als 2 %. The internal combustion engine system shown only as an example and schematically in the figure comprises an internal combustion engine 1 and an exhaust gas cleaning system 2 connected to it. The combustion air required for fuel combustion is supplied to the internal combustion engine 1 via an air supply line 3, which is fed into an intake manifold 4 of the internal combustion engine 1 downstream of a arranged turbocharger compressor 5 opens. The internal combustion engine 1 is designed as an internal combustion engine operated predominantly with excess air according to the diesel principle, ie as a compression igniter of the reciprocating piston type. NH3 is used as the fuel, which in the present case is taken from a tank 7 and is supplied to the combustion air on the inlet side of the intake manifold 4 via a first NHs supply line 6 . A feed pump used for this purpose and a control valve for controlling the amount of NHs supplied are not shown separately. Of course, NH3 can also be fed directly to the intake manifold 4 . Also possible is NHs direct injection into the individual combustion chambers of the internal combustion engine 1, which are also not shown separately here. To improve ignition of the NH3 fuel, a pilot or pre-injection of a substance that acts as an ignition promoter, such as diesel fuel, ethanol, dimethyl ether, acetone or another be provided flammable substance. Corresponding supply means are not shown for reasons of clarity. The amount of ignition promoter used is relatively small compared to the amount of the actual fuel NH3 and is preferably less than 10%, less than 5% or less than 2%.
Bei der Kraftstoffverbrennung entstehendes Abgas wird über einen Abgaskrümmer 8 und eine daran angeschlossene Abgasleitung 9 aus dem Verbrennungsmotor 1 abgeführt und der Abgasreinigungsanlage 2 zugeführt. Dabei wird eine in der Abgasleitung 9 angeordnete Turboladerturbine angetrieben, welche ihrerseits über eine nicht dargestellte Welle den Turboladerverdichter 5 antreibt. Die Abgasreinigungsanlage 2 weist vorliegend in Richtung der Abgasströmung gesehen hintereinander angeordnet in der Abgasleitung 9 folgende reinigungsaktiven Komponenten auf. Einen hier als zweiten SCR-Katalysator 11 bezeichneten Stick- oxidreduktionskatalysator, einen Oxidationskatalysator 12, einen Partikelfilter 13 sowie einen, hier als ersten SCR-Katalysator 14 bezeichneten weiteren Stickoxid- reduktionskatalysator. Exhaust gas produced during fuel combustion is discharged from the internal combustion engine 1 via an exhaust manifold 8 and an exhaust pipe 9 connected thereto and fed to the exhaust gas cleaning system 2 . In this case, a turbocharger turbine arranged in the exhaust gas line 9 is driven, which in turn drives the turbocharger compressor 5 via a shaft (not shown). In the present case, the exhaust gas purification system 2 has the following cleaning-active components arranged one behind the other in the exhaust gas line 9 viewed in the direction of the exhaust gas flow. A nitrogen oxide reduction catalytic converter, referred to here as the second SCR catalytic converter 11, an oxidation catalytic converter 12, a particle filter 13 and a further nitrogen oxide reduction catalytic converter, referred to here as the first SCR catalytic converter 14.
Die Katalysatoren 11 , 12 und 14 sind dabei bevorzugt als insbesondere keramische Wabenkörper mit durchgehenden, parallelen Kanälen ausgebildet. Dabei sind die mit dem Abgas in Kontakt kommenden Kanalwände mit der jeweiligen spezifischen katalytisch wirksamen Substanz beschichtet. Bei den SCR-Katalysatoren 11 , 14 kann es sich dabei beispielsweise um einen mit Eisen und/oder Kupfer ausgetauschten Zeolith als katalytisch wirksame Substanz handeln. Die katalytisch wirksamen Substanzen ermöglichen eine selektive Reduktion von im Abgas enthaltenem NOx mit dem hier als Reduktionsmittel eingesetzten NH3 auch unter oxidierenden Bedingungen. The catalytic converters 11, 12 and 14 are preferably in the form of, in particular, ceramic honeycomb bodies with continuous, parallel channels. The duct walls that come into contact with the exhaust gas are coated with the respective specific catalytically active substance. The SCR catalytic converters 11, 14 can, for example, be a zeolite exchanged with iron and/or copper as the catalytically active substance. The catalytically active substances enable a selective reduction of NOx contained in the exhaust gas with the NH3 used here as a reducing agent, even under oxidizing conditions.
Als katalytisch wirksame Substanz des Oxidationskatalysators kann es sich um ein fein dispergiertes Metall der Platingruppe wie Platin, Palladium und/oder Rhodium handeln. Der Partikelfilter 13 ist vorzugsweise als wanddurchströmter Wabenkörper mit eingangs- und ausgangsseitig abwechselnd verschlossenen, parallel verlaufenden Kanälen ausgebildet. The catalytically active substance of the oxidation catalyst can be a finely dispersed metal from the platinum group, such as platinum, palladium and/or rhodium. The particle filter 13 is preferably designed as a honeycomb body through which air flows through the wall, with parallel channels that are alternately closed on the inlet and outlet sides.
Was den zweiten SCR-Katalysator 11 betrifft, so ist dieser erfindungsgemäß als sogenannter passiver SCR-Katalysator ausgebildet. Darunter ist zu verstehen, dass dem zweiten SCR-Katalysator 11 das zur NOx-Reduktion erforderliche Reduktionsmittel NH3 nicht durch eine separate Zuführvorrichtung von außen zugeführt wird. Vielmehr dient als Reduktionsmittel zur selektiven NOx-Reduktion vom Verbrennungsmotor 1 ausgestoßenes NH3. Dieser sogenannte NHs-Schlupf des Verbrennungsmotors 1 ist Folge einer unvollständigen Verbrennung des Kraftstoffs NH3 im Verbrennungsmotor 1. Quelle des Reduktionsmittels NH3 zur selektiven katalytischen NOx-Reduktion im zweiten SCR-Katalysator ist somit ausschließlich der NHs-Schlupf des Verbrennungsmotors 1 . Je nach Verhältnis von NHs-Schlupf und NOx-Gehalt im Abgas, bzw. auch abhängig vom Umsatzvermögen des zweiten SCR-Katalysators 11 , können Restmengen von NOx oder NH3 in dem aus dem zweiten SCR-Katalysator 11 ausströmenden Abgas vorhanden sein. Diese werden mit der Abgasströmung in den nachgeschalteten Oxidationskatalysator 12 eingetragen. Sind Restmengen von NOx im Abgas enthalten, so erfolgt dort eine zumindest teilweise Oxidation des NOx-Bestandteils Stickstoffmonoxid (NO) zu Stickstoffdioxid (NO2) mit dem im Abgas enthaltenen Sauerstoff des mager betriebenen Verbrennungsmotors 1 . Angestrebt ist dabei ein NO-NO2- Verhältnis von etwa 1 :1 , was die katalytische NOx-Reduktion im weiter stromab angeordneten ersten SCR-Katalysator 14 verbessert bzw. erleichtert. Ist eine Restmenge von NH3 im Abgas enthalten, so wird dieses NH3 zumindest teilweise zu NO bzw. NO2 oxidiert. Jedenfalls ist davon auszugehen, dass das aus dem Oxidationskatalysator 12 ausströmende Abgas NOx aufweist, welches im weiter stromab angeordneten ersten SCR-Katalysator 14 zumindest weitgehend reduziert wird. As far as the second SCR catalytic converter 11 is concerned, this is designed according to the invention as a so-called passive SCR catalytic converter. This means that the reducing agent NH3 required for NOx reduction is not supplied to the second SCR catalytic converter 11 from outside by a separate supply device. Instead, NH3 emitted by the internal combustion engine 1 serves as a reducing agent for selective NOx reduction. This so-called NHs slip of internal combustion engine 1 is the result of incomplete combustion of the fuel NH3 in internal combustion engine 1. The source of the reducing agent NH3 for selective catalytic NOx reduction in the second SCR catalytic converter is therefore exclusively the NHs slip of internal combustion engine 1. Depending on the ratio of NHs slip and NOx content in the exhaust gas, or also depending on the conversion capacity of the second SCR catalytic converter 11 , residual amounts of NOx or NH3 can be present in the exhaust gas flowing out of the second SCR catalytic converter 11 . These are introduced into the downstream oxidation catalytic converter 12 with the exhaust gas flow. If residual amounts of NOx are contained in the exhaust gas, the NOx component nitrogen monoxide (NO) is at least partially oxidized there to form nitrogen dioxide (NO2) with the oxygen contained in the exhaust gas of the lean-burn internal combustion engine 1 . The aim here is an NO/NO2 ratio of approximately 1:1, which improves or facilitates the catalytic NOx reduction in the first SCR catalytic converter 14 arranged further downstream. If there is a residual amount of NH3 in the exhaust gas, this NH3 is at least partially oxidized to form NO or NO2. In any case, it can be assumed that the exhaust gas flowing out of the oxidation catalytic converter 12 contains NOx, which is at least largely reduced in the first SCR catalytic converter 14 arranged further downstream.
Bevor durch die Abgasleitung 9 strömendes Abgas in den ersten SCR-Katalysator 14 gelangt, wird es von Partikeln zumindest weitgehend durch Ausfilterung im Partikelfilter 13 befreit. Der erste SCR-Katalysator 14 erhält das zur selektiven NOx-Reduk- tion erforderliche Reduktionsmittel NH3 durch Zugabe über einen vorgeschalteten Injektor 15. Dieser ist über eine zweite NHs-Zufuhrleitung 16 mit dem Tank 7 verbunden ist. Eine vorzugsweise vorgesehene Förderpumpe ist dabei nicht gesondert dargestellt. NH3 kann in flüssiger Form oder gasförmig dem Tank 7 entnommen werden und durch den Injektor 15 eingangsseitig des ersten SCR-Katalysators 14 in das Abgas eingespritzt werden. Bei Zugabe von flüssigem NH3 verdampft dieses im heißen Abgas, weshalb in jedem Fall dem SCR-Katalysator 14 NH3 zumindest überwiegend in gasförmiger Form zugeführt wird. Dadurch ist eine gleichmäßige NH3- Verteilung im Abgas sichergestellt, weshalb auf einen Mischer verzichtet werden kann. Da im Gegensatz zum ersten SCR-Katalysator 14 der zweite SCR-Katalysator 11 seinen NOx-Reduktionsmittelbedarf nicht durch Zugabe zum Abgas durch einen Injektor, sondern durch NHs-Schlupf aus dem Verbrennungsmotor 1 deckt, bedarf es neben dem Injektor 15 keiner weiteren NOx-Reduktionsmittelzugabevorrichtung für die Abgasreinigungsanlage 2. Der Injektor 7 ist deshalb die einzige NOx-Redukti- onsmittelzugabevorrichtung der Abgasreinigungsanlage 2. Eine bedarfsgerechte Steuerung der NHs-Zugabe ins Abgas durch den Injektor 15 zur angestrebten möglichst vollständigen Reduktion von im Abgas enthaltenem NOx erfolgt mittels von NOx-Sensoren 17, 18 bereitgestellten Signalen, welche von einem nicht dargestellten Steuergerät entsprechend ausgewertet werden. Dabei ist ein erster NOx-Sensor 17 zur Erfassung des NOx-Gehaltes im Abgas ausgangsseitig des Oxidationskatalysators 12 bzw. zwischen dem Oxidationskatalysator 12 und dem Partikelfilter 13 vorgesehen. Dieser ermöglicht die Ermittlung des NOx-Gehalt des in den ersten SCR-Katalysator 14 einströmenden Abgases. Aus dem ermittelten NOx- Gehalt des Abgases kann wiederum der NHs-Bedarf zur Reduktion von im Abgas enthaltenem NOx im ersten SCR-Katalysator 14 ermittelt und der Injektor 15 entsprechend angesteuert werden. Sofern Oxidationskatalysator 12 und Partikelfilter 13 zu einem integralen gemeinsamen Bauteil zusammengefasst sind, so ist der erste NOx-Sensor 17 vorzugsweise ausgangsseitige dieses Bauteils angeordnet. Before exhaust gas flowing through the exhaust line 9 reaches the first SCR catalytic converter 14 , it is at least largely freed from particles by being filtered out in the particle filter 13 . The first SCR catalytic converter 14 receives the reducing agent NH3 required for selective NOx reduction by adding it via an upstream injector 15. This is connected to the tank 7 via a second NHs supply line 16. A feed pump that is preferably provided is not shown separately. NH3 can be taken from the tank 7 in liquid form or in gaseous form and injected into the exhaust gas by the injector 15 on the inlet side of the first SCR catalytic converter 14 . When liquid NH3 is added, it evaporates in the hot exhaust gas, which is why the SCR catalytic converter 14 is supplied with NH3 at least predominantly in gaseous form. This ensures an even NH3 distribution in the flue gas, which is why a mixer is not required. Since, in contrast to the first SCR catalytic converter 14, the second SCR catalytic converter 11 does not cover its NOx reducing agent requirement by adding it to the exhaust gas through an injector, but rather by NHs slip from the internal combustion engine 1, no further NOx reducing agent adding device is required in addition to the injector 15 for the emission control system 2. The injector 7 is therefore the only NOx reducing agent addition device of the emission control system 2. Needs-based control of the addition of NHs to the exhaust gas by the injector 15 for the desired complete reduction of NOx contained in the exhaust gas takes place using signals provided by NOx sensors 17, 18, which are evaluated accordingly by a control unit, not shown. A first NOx sensor 17 for detecting the NOx content in the exhaust gas is provided on the outlet side of the oxidation catalytic converter 12 or between the oxidation catalytic converter 12 and the particle filter 13 . This enables the NOx content of the exhaust gas flowing into the first SCR catalytic converter 14 to be determined. From the determined NOx content of the exhaust gas, the NHs requirement for the reduction of NOx contained in the exhaust gas in the first SCR catalytic converter 14 can in turn be determined and the injector 15 can be controlled accordingly. If the oxidation catalytic converter 12 and particle filter 13 are combined to form an integral common component, the first NOx sensor 17 is preferably arranged on the output side of this component.
Ein zweiter NOx-Sensor 18 ist ausgangsseitig des ersten SCR-Katalysators 14 angeordnet und ermöglicht eine Ermittlung von gegebenenfalls durch den ersten SCR-Katalysator 14 schlüpfendem NOx. In diesem Fall kann die durch den Injektor 15 bewirkte Anreicherung des Abgases mit dem Reduktionsmittel NH3 angepasst werden. A second NOx sensor 18 is arranged on the output side of the first SCR catalytic converter 14 and makes it possible to determine any NOx that may have slipped through the first SCR catalytic converter 14 . In this case, the enrichment of the exhaust gas caused by the injector 15 with the reducing agent NH3 can be adjusted.
Es sei angemerkt, dass einer oder beide der hier als NOx-Sensoren bezeichneten Sensoren 17, 18 auch als kombinierte NOx/NH3-Sensoren ausgebildet sein können. Dadurch können neben den NOx-Gehalten im Abgas stromauf bzw. stromab des ersten SCR-Katalysators 14 auch die korrespondierenden NHs-Gehalte ermittelt werden, was gegebenenfalls die Genauigkeit der NHs-Dosierung verbessern kann. It should be noted that one or both of the sensors 17, 18 referred to here as NOx sensors can also be designed as combined NOx/NH3 sensors. As a result, in addition to the NOx contents in the exhaust gas upstream and downstream of the first SCR catalytic converter 14, the corresponding NHs contents can also be determined, which can improve the accuracy of the NHs metering if necessary.
Insgesamt ist durch das erfindungsgemäße Verbrennungsmotorsystem ein äußerst umweltfreundlicher Betrieb eines entsprechenden Fahrzeugs ermöglicht. Es werden nicht nur Emissionen von klimaschädlichem CO2 zumindest weitgehend vermieden, sondern auch zumindest weitestgehend die Emissionen von Kohlenwasserstoffen NOx, NH3 und Partikeln. Bezugszeichenhste Overall, the internal combustion engine system according to the invention enables an extremely environmentally friendly operation of a corresponding vehicle. Not only emissions of climate-damaging CO2 are at least largely avoided, but also at least largely emissions of hydrocarbons NOx, NH3 and particles. reference number
Verbrennungsmotorcombustion engine
Abgasnachbehandlungsanlageexhaust aftertreatment system
Luftzufuhrleitung air supply line
Saugrohr intake manifold
T urbolader-Verdichter Turbocharger compressor
Erste NH3-Zufuhrleitung First NH3 supply line
Tank tank
Abgaskrümmer exhaust manifold
Abgasleitung exhaust pipe
Turbolader-Turbine Turbocharged Turbine
Zweiter SCR-KatalysatorSecond SCR catalytic converter
Oxidationskatalysator oxidation catalyst
Partikelfilter particle filter
Erster SCR-Katalysator First SCR catalytic converter
Injektor injector
Zweite NH3-Zufuhrleitung Second NH3 supply line
Erster NOx-Sensor First NOx sensor
Zweiter NOx-Sensor Second NOx sensor

Claims

Patentansprüche Verbrennungsmotorsystem umfassend einen zumindest überwiegend mit Ammoniak als Kraftstoff betriebenen Verbrennungsmotor (1 ) mit daran angeschlossener Abgasreinigungsanlage (2) zur Reinigung eines vom Verbrennungsmotor (1 ) abgegebenen Abgases, wobei die Abgasreinigungsanlage (2) einen ersten SCR-Katalysator (14) zur Reduktion von im Abgas enthaltenen Stickoxiden aufweist, dadurch gekennzeichnet, dass die Abgasreinigungsanlage (2) ferner einen zweiten SCR-Katalysator (11 ) zur Reduktion von im Abgas enthaltenen Stickoxiden aufweist, der dem ersten SCR-Katalysator (14) strömungstechnisch vorgeschaltet ist. Verbrennungsmotorsystem nach Anspruch 1 , dadurch gekennzeichnet, dass die Abgasreinigungsanlage (2) genau einen Injektor (15) zur Zugabe von Ammoniak zum Abgas aufweist, wobei der Injektor (15) zur Zugabe von Ammoniak zum Abgas eingangsseitig des ersten SCR-Katalysators (14) ausgebildet ist. Verbrennungsmotorsystem nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Abgasreinigungsanlage (2) einen Partikelfilter (13) zur Ausfilterung von im Abgas enthaltenen Partikeln aufweist, wobei der Partikelfilter (13) strömungstechnisch vor dem ersten SCR-Katalysator (14) und hinter dem zweiten SCR-Katalysator (11 ) angeordnet ist. Verbrennungsmotorsystem nach Anspruch 3, dadurch gekennzeichnet, dass die Abgasreinigungsanlage (2) einen Oxidationskatalysator (12) aufweist, der strömungstechnisch zwischen dem zweiten SCR-Katalysator(11 ) und dem Partikelfilter (13) angeordnet ist. Verbrennungsmotorsystem nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass der Verbrennungsmotor (1 ) als kompressionsgezündeter Verbrennungsmotor ausgebildet ist. Betriebsverfahren zum Betreiben eines Verbrennungsmotorsystems, bei welchem von einem zumindest überwiegend mit Ammoniak als Kraftstoff betriebenen Verbrennungsmotor (1 ) abgegebenes Abgas gereinigt wird, wobei im Abgas enthaltene Stickoxide an einem ersten SCR-Katalysator (14) mittels dem Abgas durch einen Injektor (15) zugegebenem Ammoniak reduziert werden, und im Abgas enthaltene Stickoxide zusätzlich an einem dem ersten SCR-Katalysator (14) strömungstechnisch vorgeschalteten zweiten SCR- Katalysator (11 ) mittels vom Verbrennungsmotor (1) abgegebenem Ammoniak reduziert werden. Betriebsverfahren nach Anspruch 6, dadurch gekennzeichnet, dass im Abgas enthaltene Partikel mittels eines strömungstechnisch zwischen dem ersten SCR-Katalysator (14) und dem zweiten SCR-Katalysator (11 ) angeordneten Partikelfilter (13) aus dem Abgas ausgefiltert werden. Betriebsverfahren nach Anspruch 6 oder 7, dadurch gekennzeichnet, dass der Verbrennungsmotor (1 ) zumindest überwiegend mit Luftüberschuss betrieben wird. Claims Internal combustion engine system comprising an internal combustion engine (1) which is operated at least predominantly with ammonia as fuel and has an exhaust gas cleaning system (2) connected thereto for cleaning an exhaust gas emitted by the internal combustion engine (1), the exhaust gas cleaning system (2) having a first SCR catalytic converter (14) for reducing has nitrogen oxides contained in the exhaust gas, characterized in that the exhaust gas cleaning system (2) also has a second SCR catalytic converter (11) for reducing nitrogen oxides contained in the exhaust gas, which is upstream of the first SCR catalytic converter (14) in terms of flow. Internal combustion engine system according to Claim 1, characterized in that the exhaust gas cleaning system (2) has exactly one injector (15) for adding ammonia to the exhaust gas, the injector (15) for adding ammonia to the exhaust gas being designed on the input side of the first SCR catalytic converter (14). is. Internal combustion engine system according to Claim 1 or 2, characterized in that the exhaust gas cleaning system (2) has a particle filter (13) for filtering out particles contained in the exhaust gas, the particle filter (13) being fluidically upstream of the first SCR catalytic converter (14) and downstream of the second SCR catalyst (11) is arranged. Internal combustion engine system according to claim 3, characterized in that the exhaust gas cleaning system (2) has an oxidation catalytic converter (12) which is arranged in terms of flow between the second SCR catalytic converter (11) and the particle filter (13). Internal combustion engine system according to one of claims 1 to 4, characterized in that the internal combustion engine (1) is designed as a compression-ignited internal combustion engine. Operating method for operating an internal combustion engine system, in which exhaust gas emitted by an internal combustion engine (1) that is at least predominantly operated with ammonia as fuel is cleaned, nitrogen oxides contained in the exhaust gas being added to a first SCR catalytic converter (14) by means of the exhaust gas through an injector (15). Ammonia are reduced, and nitrogen oxides contained in the exhaust gas are additionally reduced at a second SCR catalytic converter (11) upstream of the first SCR catalytic converter (14) by means of ammonia emitted by the internal combustion engine (1). Operating method according to Claim 6, characterized in that particles contained in the exhaust gas are filtered out of the exhaust gas by means of a particle filter (13) arranged in terms of flow between the first SCR catalytic converter (14) and the second SCR catalytic converter (11). Operating method according to Claim 6 or 7, characterized in that the internal combustion engine (1) is operated at least predominantly with excess air.
PCT/AT2022/060433 2021-12-10 2022-12-09 Combustion engine system comprising an ammonia combustion engine and connected exhaust gas cleaning system and operating method for same WO2023102590A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202280070931.1A CN118140041A (en) 2021-12-10 2022-12-09 Internal combustion engine system having an ammonia combustion engine and an exhaust gas purification device connected thereto, and method for operating the same
DE112022003897.7T DE112022003897A5 (en) 2021-12-10 2022-12-09 Combustion engine system with an ammonia combustion engine and connected exhaust gas purification system and operating method therefor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ATA50988/2021 2021-12-10
ATA50988/2021A AT525550B1 (en) 2021-12-10 2021-12-10 Internal combustion engine system with an ammonia internal combustion engine and exhaust gas purification system connected thereto and operating method therefor

Publications (1)

Publication Number Publication Date
WO2023102590A1 true WO2023102590A1 (en) 2023-06-15

Family

ID=84980882

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AT2022/060433 WO2023102590A1 (en) 2021-12-10 2022-12-09 Combustion engine system comprising an ammonia combustion engine and connected exhaust gas cleaning system and operating method for same

Country Status (4)

Country Link
CN (1) CN118140041A (en)
AT (1) AT525550B1 (en)
DE (1) DE112022003897A5 (en)
WO (1) WO2023102590A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100019506A1 (en) 2008-07-22 2010-01-28 Caterpillar Inc. Power system having an ammonia fueled engine
WO2019159151A1 (en) * 2018-02-19 2019-08-22 Basf Corporation Exhaust gas treatment system with upstream scr catalyst
CN111255560B (en) * 2020-01-15 2021-08-13 北京工业大学 Hydrogen-ammonia dual-fuel piston machine and control method

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8534237B2 (en) * 2010-04-22 2013-09-17 Toyota Jidosha Kabushiki Kaisha Control system of internal combustion engine
CN110219718B (en) * 2019-07-16 2023-12-15 潍柴动力股份有限公司 Post-treatment system for urea injection before vortex and control method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100019506A1 (en) 2008-07-22 2010-01-28 Caterpillar Inc. Power system having an ammonia fueled engine
WO2019159151A1 (en) * 2018-02-19 2019-08-22 Basf Corporation Exhaust gas treatment system with upstream scr catalyst
CN111255560B (en) * 2020-01-15 2021-08-13 北京工业大学 Hydrogen-ammonia dual-fuel piston machine and control method

Also Published As

Publication number Publication date
CN118140041A (en) 2024-06-04
AT525550B1 (en) 2023-05-15
AT525550A4 (en) 2023-05-15
DE112022003897A5 (en) 2024-05-23

Similar Documents

Publication Publication Date Title
EP2635790B1 (en) Motor-vehicle internal combustion engine with exhaust-gas recirculation
DE60030241T2 (en) Exhaust gas purification system of an internal combustion engine operating with excess air
DE102012205678B4 (en) Exhaust gas treatment system for an internal combustion engine
EP1625286A1 (en) Regeneration of a particle trap
WO2017088958A1 (en) Exhaust gas post-treatment device for an internal combustion engine, and method for operating a drive device with an exhaust gas post-treatment device of this type
DE102006007122A1 (en) Operating process for internal combustion engine involves reporting suitable combinations of engine operating values for preset nitrogen oxide emission value
DE102014109450A1 (en) System and method for desulphurizing a lean NOx trap
DE102011014158A1 (en) Compressor bypass for exhaust gas for regeneration of a particle trap
DE102008051958A1 (en) Diesel exhaust gas temperature reduction
DE102015016986A1 (en) Exhaust after-treatment device for an internal combustion engine
WO2007131807A1 (en) Injection device, location of said device in an internal combustion engine and method and device for operating said internal combustion engine
DE102016116683A1 (en) GAS / LIQUID MIXING DEVICE FOR EXHAUST GAS TREATMENT
DE102021111152A1 (en) Motor arrangement and procedure
WO2009065555A1 (en) Exhaust gas after-treatment device for an internal combustion engine and method for the after-treatment of exhaust gases of an internal combustion engine
AT525550B1 (en) Internal combustion engine system with an ammonia internal combustion engine and exhaust gas purification system connected thereto and operating method therefor
WO2002048512A1 (en) Exhaust gas purification system and a method for purifying exhaust gases
DE102018123586A1 (en) Device and method for exhaust gas aftertreatment of an internal combustion engine
DE102008002469A1 (en) Method and device for exhaust gas purification
DE102017006738B4 (en) Device and method for exhaust gas cleaning systems of diesel vehicles, in particular for retrofitting existing diesel vehicles with a diesel particle filter, in particular for inner-city driving
EP2573340B1 (en) Exhaust gas device for a combustion engine
DE102019006494B4 (en) Exhaust system for an internal combustion engine of a motor vehicle, drive device for a motor vehicle and motor vehicle
DE102020126135B4 (en) Combustion engine and method for internal engine reduction of nitrogen oxide emissions of a combustion engine
DE102017010267A1 (en) Internal combustion engine, in particular diesel engine, with exhaust aftertreatment
AT525793B1 (en) Exhaust gas purification system for a motor vehicle powered by a diesel engine and operating method therefor
DE102017201399A1 (en) aftertreatment system

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22843606

Country of ref document: EP

Kind code of ref document: A1

REG Reference to national code

Ref country code: DE

Ref legal event code: R225

Ref document number: 112022003897

Country of ref document: DE