WO2022128481A1 - Method for cleaning a storage catalyst, and corresponding device - Google Patents

Method for cleaning a storage catalyst, and corresponding device Download PDF

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Publication number
WO2022128481A1
WO2022128481A1 PCT/EP2021/083807 EP2021083807W WO2022128481A1 WO 2022128481 A1 WO2022128481 A1 WO 2022128481A1 EP 2021083807 W EP2021083807 W EP 2021083807W WO 2022128481 A1 WO2022128481 A1 WO 2022128481A1
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WO
WIPO (PCT)
Prior art keywords
hydrocarbons
storage
catalytic converter
storage catalytic
fresh air
Prior art date
Application number
PCT/EP2021/083807
Other languages
German (de)
French (fr)
Inventor
Lorenzo Pace
Katrin Konieczny
Rolf BRÜCK
Original Assignee
Vitesco Technologies GmbH
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Publication date
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Publication of WO2022128481A1 publication Critical patent/WO2022128481A1/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
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0807—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
    • F01N3/0835—Hydrocarbons
    • 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
    • F01N3/0871—Regulation of absorbents or adsorbents, e.g. purging
    • 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
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • 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
    • F01N3/22—Control of additional air supply only, e.g. using by-passes or variable air pump drives
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/30—Arrangements for supply of additional air
    • F01N3/32—Arrangements for supply of additional air using air pump
    • 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
    • F01N3/36—Arrangements for supply of additional fuel

Definitions

  • the invention relates to a method for reducing hydrocarbons in a storage catalytic converter for hydrocarbons, the storage catalytic converter being arranged in an exhaust tract of an internal combustion engine and being set up to take up unburned hydrocarbons from the exhaust gas flow, a scavenging pump being provided which is set up to draw a flow of fresh air through the To conduct storage catalyst.
  • the invention also relates to a device for carrying out the method.
  • different catalysts are used to chemically convert the exhaust gas.
  • the chemical conversion on the catalysts can only take place above a minimum temperature that is dependent on the catalyst used in each case.
  • so-called storage catalytic converters are also used, which serve to temporarily store pollutants, for example nitrogen oxides or hydrocarbons.
  • the aim here is to at least temporarily bind free nitrogen oxides and hydrocarbons in the exhaust gas flow and release them again under suitable operating conditions in order to then convert them as completely as possible in the exhaust tract in order to prevent uncontrolled release into the environment.
  • the storage catalytic converters are either designed to absorb the nitrogen oxides or the hydrocarbons or to release them.
  • the uptake, the adsorption, or the release, the desorption depend on the saturation degree of the coating of the catalyst, the concentration of hydrocarbons in the gas phase and the temperature.
  • hydrocarbons are bound to the storage catalyst as long as the temperature is below a certain value, the concentration in the gas phase is higher than on the catalyst surface and as long as the coating is not already saturated.
  • the temperature thresholds that are relevant in each case depend, for example, on the coating applied to the substrate of the catalyst by means of a washcoat.
  • this temperature threshold When this temperature threshold is exceeded, the bound hydrocarbons are released and can convert on the downstream catalysts, for example the three-way catalyst. If the necessary temperature threshold is not reached, for example on a very short journey, it may happen that the bound hydrocarbons are not completely desorbed. A part of the hydrocarbons therefore remains on the storage catalytic converter and occupies a certain proportion of the storage capacity.
  • the internal combustion engine is restarted, in particular after a cold start, not all of the hydrocarbons contained in the exhaust gas can be bound to the storage catalytic converter.
  • the downstream catalytic converters are not yet fully functional due to the still low exhaust gas temperature, these hydrocarbons that cannot be stored are released into the environment. This is particularly disadvantageous since this leads to significantly increased environmental pollution, which is to be prevented in principle.
  • One exemplary embodiment of the invention relates to a method for reducing hydrocarbons in a storage catalytic converter for hydrocarbons, the storage catalytic converter being arranged in an exhaust tract of an internal combustion engine and being set up to take up unburned hydrocarbons from the exhaust gas flow, a scavenging pump being provided which is set up to draw in a fresh air flow through the storage catalytic converter and to intermediately store the hydrocarbons thus released from the storage catalytic converter in a storage container for hydrocarbons, with the method generating an air flow that is independent of an exhaust gas flow in the exhaust gas tract and being guided through the storage catalytic converter and then being guided through a storage container.
  • the scavenging pump is preferably designed in such a way that it can generate an air flow which can be routed via suitable lines into the exhaust gas tract and can be routed through the storage catalytic converter.
  • air can be drawn in from the environment and passed through the storage catalytic converter.
  • the air flow generated in this way is enriched with hydrocarbons as it flows through the storage catalytic converter, as a result of which the quantity of hydrocarbons remaining in the storage catalytic converter is reduced.
  • the hydrocarbon-enriched air stream is sent to a storage tank where the hydrocarbons are received and retained.
  • the fresh air flow is passed through the storage catalytic converter while the internal combustion engine is not being operated. This is preferably the case because, on the one hand, this prevents the unburned hydrocarbons from being blown out into the environment with the normal exhaust gas flow, and it also prevents the scavenging pump from having to work counter to the exhaust gas flow. As a result, the scavenging pump can be made smaller. It is also advantageous if the scavenging pump sucks in fresh air from the environment and conveys it through the storage catalytic converter in the opposite direction to the usual main flow direction of the exhaust gas.
  • Fresh air from the environment is advantageous because it will generally have a significantly lower concentration of hydrocarbons, so that there will be a significant concentration gradient between the storage catalytic converter and the fresh air flow. This favors the release of the hydrocarbons from the catalyst into the air stream.
  • a preferred exemplary embodiment is characterized in that the hydrocarbons stored in the storage container are released into the combustion chamber of the internal combustion engine at a defined point in time.
  • the storage canister is designed to strip the hydrocarbons from the airflow directed through the storage canister.
  • a binder can be provided in the storage container, for example activated carbon.
  • the storage tank then stores the released hydrocarbons for a certain time. At favorable points in time, the hydrocarbons collected in the storage container can then be returned to the combustion in the internal combustion engine. This prevents unburned hydrocarbons from escaping into the environment and thus leading to undesirable environmental pollution.
  • the fresh air flow conducted through the storage catalytic converter is enriched with hydrocarbons present in the storage catalytic converter due to the differences in concentration of hydrocarbons between the fresh air and the storage catalytic converter.
  • the fresh air flow generated by the scavenging pump can be steered by at least one control valve, with the control valve opening or closing flow paths to the storage catalytic converter and/or to a fuel tank.
  • the scavenging pump can, in addition to the purpose according to the invention, also be used to drain dissolved hydrocarbons from the fuel tank or to supply other systems with an air flow.
  • the provision of control valves is advantageous in order to generate an air flow that is suitable in each case for the corresponding application.
  • the storage container is preferably designed in such a way that it can temporarily store hydrocarbons from a number of applications, for example from the fuel tank and the storage catalytic converter.
  • the object with regard to the device is solved by a device having the features of claim 6 .
  • One exemplary embodiment of the invention relates to a device for releasing hydrocarbons from a storage catalytic converter for hydrocarbons, the device having a flow path for exhaust gases from an internal combustion engine, in which the storage catalytic converter is arranged, with a scavenging pump being provided which is designed to direct a flow of fresh air through the To lead storage catalyst towards a storage container.
  • the storage container has a binder for releasing the hydrocarbons contained in the air flow generated by the scavenging pump.
  • a binder can be, for example, activated carbon, which binds the free hydrocarbons entrained in the air stream, which can be present, for example, as fine droplets, and removes them from the air stream.
  • the scavenging pump is also set up to flush gaseous hydrocarbons out of a fuel tank. Preference is given to using the scavenging pump that is already being used to vent the fuel tank, since this allows the overall system costs to be kept low and only additional lines and valves have to be provided to allow the air flow to the storage catalytic converter and from the storage catalytic converter into the Storage container and, if necessary, to conduct from the storage container in the intake tract.
  • At least one control valve is provided, which is set up to direct the fresh air flow generated by the scavenging pump either through the fuel tank into the storage tank or through the storage catalytic converter into the storage tank.
  • the scavenging pump can be used for a number of applications, as a result of which the outlay on hardware is reduced and the device is therefore more cost-effective.
  • FIG. 1 shows a schematic view of an exhaust system with a storage catalytic converter, a scavenging pump, and a storage tank.
  • Figure 1 shows a schematic view of a device 1 for flushing a storage catalytic converter 3.
  • the storage catalytic converter 3 is installed in an exhaust tract 2 of an internal combustion engine 9 and is used to store unburned hydrocarbons in the exhaust gas, which flows through the exhaust tract along the direction marked by arrow 4 2 is flowable.
  • Storage catalysts 3 and how they work are known in the prior art.
  • the storage catalytic converter 3 is preferably constructed as a metallic substrate with a corresponding coating.
  • further components for exhaust gas aftertreatment can be arranged downstream of storage catalytic converter 3. It is particularly advantageous to use the storage catalytic converter 3 in the vicinity of the underbody of the vehicle. In the case of an arrangement on or near the underbody, the arrangement of the three-way catalytic converter at a short distance from the internal combustion engine 9 is preferable, in particular in order to use the quickly reached high temperatures directly after the internal combustion engine 9 in the event of a cold start.
  • a scavenging pump which can generate an air flow, is identified by the reference number 5 .
  • Fresh air from the environment is preferably sucked in here.
  • the air flow then flows through the storage catalytic converter 3 counter to the main flow direction 4 of the exhaust tract 2 .
  • the air flow absorbs the hydrocarbons and flows out of the exhaust tract 2 along a discharge line 7 .
  • the air stream flows along the scavenging pump 5 into the storage container 6 in which the hydrocarbons entrained in the air stream are bound in the activated carbon that flows through.
  • the air stream then flows out into the environment via a discharge line 11 .
  • the hydrocarbons stored in the storage tank 6 can be fed back to the internal combustion engine along the feed line 8 .
  • control valves that control the air flow can be provided in the supply line 8 and/or the discharge line 7 . This is particularly advantageous when the scavenging pump 5 is also used, for example, to vent the fuel tank 10 or to flush out the hydrocarbons located above the fuel level there. The flushing pump 5 and the storage tank 6 can then be used for both purposes.
  • FIG. 1 shows a fuel tank 10 which is connected to the storage tank 6 via a connecting line 12 .
  • the exemplary embodiment in FIG. 1 has no restrictive character and serves to clarify the idea of the invention.

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

Abstract

The invention relates to a method for reducing the quantity of hydrocarbons in a storage catalyst (3) for hydrocarbons, wherein: the storage catalyst (3) is located in an exhaust tract (2) of an internal combustion engine (9) and is designed to receive unburned hydrocarbons from the exhaust stream; a scavenging pump (5) is provided which is designed to conduct a flow of fresh air through the storage catalyst (3) and to intermediately store, in a storage container (6) for hydrocarbons, the hydrocarbons released from the storage catalyst (3) as a result; and, by means of the method, a flow of air that is independent of an exhaust flow in the exhaust tract (2) is generated and is conducted through the storage catalyst (3) and subsequently conducted through a storage container (6). The invention also relates to a device for carrying out the method.

Description

Beschreibung description
Verfahren zur Reinigung eines Speicherkatalysators und Vorrichtung hierzu Method for cleaning a storage catalytic converter and device therefor
Technisches Gebiet technical field
Die Erfindung betrifft ein Verfahren zur Reduzierung von Kohlenwasserstoffen in einem Speicherkatalysator für Kohlenwasserstoffe, wobei der Speicherkatalysator in einem Abgastrakt einer Verbrennungskraftmaschine angeordnet ist und dazu eingerichtet ist unverbrannte Kohlenwasserstoffe aus dem Abgasstrom aufzunehmen, wobei eine Spülpumpe vorgesehen ist, welcher dazu eingerichtet ist einen Frischluftstrom durch den Speicherkatalysator zu leiten. Außerdem betrifft die Erfindung eine Vorrichtung zur Durchführung des Verfahrens. The invention relates to a method for reducing hydrocarbons in a storage catalytic converter for hydrocarbons, the storage catalytic converter being arranged in an exhaust tract of an internal combustion engine and being set up to take up unburned hydrocarbons from the exhaust gas flow, a scavenging pump being provided which is set up to draw a flow of fresh air through the To conduct storage catalyst. The invention also relates to a device for carrying out the method.
Stand der Technik State of the art
Zum Zwecke der Abgasnachbehandlung werden unterschiedliche Katalysatoren zur chemischen Umwandlung des Abgases eingesetzt. Die chemische Umwandlung an den Katalysatoren kann erst ab einer vom jeweils verwendeten Katalysator abhängigen Mindesttemperatur stattfinden. Daneben werden auch sogenannte Speicherkatalysatoren verwendet, die der Zwischenspeicherung von Schadstoffen, beispielsweise Stickoxiden oder Kohlenwasserstoffen dienen. Hier wird insbesondere das Ziel verfolgt freie Stickoxide und Kohlenwasserstoffe im Abgasstrom zumindest temporär zu binden, und diese bei geeigneten Betriebsbedingungen wieder freizusetzen, um diese dann im Abgastrakt möglichst vollständig umzusetzen, um ein unkontrolliertes Austreten in die Umwelt zu verhindern. For the purpose of exhaust gas aftertreatment, different catalysts are used to chemically convert the exhaust gas. The chemical conversion on the catalysts can only take place above a minimum temperature that is dependent on the catalyst used in each case. In addition, so-called storage catalytic converters are also used, which serve to temporarily store pollutants, for example nitrogen oxides or hydrocarbons. The aim here is to at least temporarily bind free nitrogen oxides and hydrocarbons in the exhaust gas flow and release them again under suitable operating conditions in order to then convert them as completely as possible in the exhaust tract in order to prevent uncontrolled release into the environment.
Die Speicherkatalysatoren sind dabei abhängig von den jeweils vorherrschenden Bedingungen, wie beispielsweise der Temperatur entweder dazu ausgelegt die Stickoxide oder die Kohlenwasserstoffe aufzunehmen oder diese abzugeben. Depending on the prevailing conditions, such as the temperature, the storage catalytic converters are either designed to absorb the nitrogen oxides or the hydrocarbons or to release them.
Das Aufnehmen, die Adsorption, beziehungsweise die Abgabe, die Desorption, hängen im Falle eines Speicherkatalysators für Kohlenwasserstoffe vom Sätti- gungsgrad der Beschichtung des Katalysators, der Konzentration der Kohlenwasserstoffe in der Gasphase, sowie der Temperatur ab. Kohlenwasserstoffe werden am Speicherkatalysator beispielsweise gebunden, solange die Temperatur unter einem gewissen Wert liegt, die Konzentration in der Gasphase höher ist als an der Katalysatoroberfläche und solange die Beschichtung nicht bereits gesättigt ist. Die jeweils relevanten Temperaturschwellen hängen dabei beispielsweise von der per Washcoat auf das Substrat des Katalysators aufgetragenen Beschichtung ab. In the case of a storage catalytic converter for hydrocarbons, the uptake, the adsorption, or the release, the desorption, depend on the saturation degree of the coating of the catalyst, the concentration of hydrocarbons in the gas phase and the temperature. For example, hydrocarbons are bound to the storage catalyst as long as the temperature is below a certain value, the concentration in the gas phase is higher than on the catalyst surface and as long as the coating is not already saturated. The temperature thresholds that are relevant in each case depend, for example, on the coating applied to the substrate of the catalyst by means of a washcoat.
Beim Übersteigen dieser Temperaturschwelle werden die gebundenen Kohlenwasserstoffe freigesetzt und können an den nachfolgenden Katalysatoren, beispielsweise dem Drei-Wege-Katalysator konvertieren. Kommt es zu dem Fall, dass die notwendige Temperaturschwelle nicht erreicht wird, beispielsweise bei einer sehr kurzen Fahrt, kann es vorkommen, dass die gebundenen Kohlenwasserstoffe nicht vollständig desorbiert werden. Ein Teil der Kohlenwasserstoffe verbleibt somit am Speicherkatalysator und besetzt einen gewissen Anteil der Speicherkapazität. Bei einem erneuten Start der Verbrennungskraftmaschine, insbesondere nach einem Kaltstart, können nicht alle im Abgas enthaltenen Kohlenwasserstoffe an dem Speicherkatalysator gebunden werden. Da aber aufgrund der noch niedrigen Abgastemperatur auch die nachfolgenden Katalysatoren noch nicht vollfunktionsfähig sind, werden diese nicht speicherbaren Kohlenwasserstoffe in die Umwelt abgegeben. Dies ist insbesondere nachteilig, da es hierdurch zu deutlich erhöhten Umweltbelastungen kommt, was grundsätzlich verhindert werden soll. When this temperature threshold is exceeded, the bound hydrocarbons are released and can convert on the downstream catalysts, for example the three-way catalyst. If the necessary temperature threshold is not reached, for example on a very short journey, it may happen that the bound hydrocarbons are not completely desorbed. A part of the hydrocarbons therefore remains on the storage catalytic converter and occupies a certain proportion of the storage capacity. When the internal combustion engine is restarted, in particular after a cold start, not all of the hydrocarbons contained in the exhaust gas can be bound to the storage catalytic converter. However, since the downstream catalytic converters are not yet fully functional due to the still low exhaust gas temperature, these hydrocarbons that cannot be stored are released into the environment. This is particularly disadvantageous since this leads to significantly increased environmental pollution, which is to be prevented in principle.
Darstellung der Erfindung, Aufgabe, Lösung, Vorteile Presentation of the invention, task, solution, advantages
Daher ist es die Aufgabe der vorliegenden Erfindung ein Verfahren zu schaffen, welches es ermöglicht die im Speicherkatalysator verbleibende Restmenge an Kohlenwasserstoffen weitestmöglich zu reduzieren und somit die Umweltbelastung möglichst gering zu halten. Außerdem ist es die Aufgabe eine Vorrichtung zur Durchführung des Verfahrens zu schaffen. Die Aufgabe hinsichtlich des Verfahrens wird durch ein Verfahren mit den Merkmalen von Anspruch 1 gelöst. It is therefore the object of the present invention to create a method which makes it possible to reduce the residual amount of hydrocarbons remaining in the storage catalytic converter as far as possible and thus to keep the environmental pollution as low as possible. Another object is to create a device for carrying out the method. The object with regard to the method is solved by a method having the features of claim 1 .
Ein Ausführungsbeispiel der Erfindung betrifft ein Verfahren zur Reduzierung von Kohlenwasserstoffen in einem Speicherkatalysator für Kohlenwasserstoffe, wobei der Speicherkatalysator in einem Abgastrakt einer Verbrennungskraftmaschine angeordnet ist und dazu eingerichtet ist unverbrannte Kohlenwasserstoffe aus dem Abgasstrom aufzunehmen, wobei eine Spülpumpe vorgesehen ist, welcher dazu eingerichtet ist einen Frischluftstrom durch den Speicherkatalysator zu leiten und die hierdurch aus dem Speicherkatalysator ausgelösten Kohlenwasserstoffe in einem Speicherbehälter für Kohlenwasserstoffe zwischenzuspeichern, wobei durch das Verfahren ein von einem Abgasstrom im Abgastrakt unabhängiger Luftstrom erzeugt wird und durch den Speicherkatalysator geleitet wird und anschließend durch einen Speicherbehälter geleitet wird. One exemplary embodiment of the invention relates to a method for reducing hydrocarbons in a storage catalytic converter for hydrocarbons, the storage catalytic converter being arranged in an exhaust tract of an internal combustion engine and being set up to take up unburned hydrocarbons from the exhaust gas flow, a scavenging pump being provided which is set up to draw in a fresh air flow through the storage catalytic converter and to intermediately store the hydrocarbons thus released from the storage catalytic converter in a storage container for hydrocarbons, with the method generating an air flow that is independent of an exhaust gas flow in the exhaust gas tract and being guided through the storage catalytic converter and then being guided through a storage container.
Die Spülpumpe ist bevorzugt derart ausgebildet, dass sie einen Luftstrom erzeugen kann, welcher über geeignete Leitungen in den Abgastrakt geführt werden kann und durch den Speicherkatalysator geleitet werden kann. Hierzu kann beispielweise Luft aus der Umgebung angesaugt werden und durch den Speicherkatalysator geleitet werden. Der so erzeugte Luftstrom reichert sich beim Durchströmen des Speicherkatalysators mit Kohlenwasserstoffen an, wodurch die im Speicherkatalysator verbleibende Menge an Kohlenwasserstoffen reduziert wird. Der mit Kohlenwasserstoffen angereicherte Luftstrom wird schließlich in einen Speicherbehälter geleitet, wo die Kohlenwasserstoffe aufgenommen und zurückgehalten werden. The scavenging pump is preferably designed in such a way that it can generate an air flow which can be routed via suitable lines into the exhaust gas tract and can be routed through the storage catalytic converter. For this purpose, for example, air can be drawn in from the environment and passed through the storage catalytic converter. The air flow generated in this way is enriched with hydrocarbons as it flows through the storage catalytic converter, as a result of which the quantity of hydrocarbons remaining in the storage catalytic converter is reduced. Finally, the hydrocarbon-enriched air stream is sent to a storage tank where the hydrocarbons are received and retained.
Besonders vorteilhaft ist es, wenn der Frischluftstrom durch den Speicherkatalysator geleitet wird, während die Verbrennungskraftmaschine nicht betrieben wird. Dies ist bevorzugt der Fall, da so einerseits verhindert wird, dass die unverbrannten Kohlenwasserstoffe mit dem normalen Abgasstrom in die Umgebung ausgeblasen werden und weiterhin wird vermieden, dass die Spülpumpe entgegen dem Abgasstrom arbeiten muss. Dadurch kann die Spülpumpe kleiner dimensioniert werden. Auch ist es vorteilhaft, wenn die Spülpumpe Frischluft aus der Umgebung ansaugt und entgegen der gewöhnlichen Hauptströmungsrichtung des Abgases durch den Speicherkatalysator fördert. It is particularly advantageous if the fresh air flow is passed through the storage catalytic converter while the internal combustion engine is not being operated. This is preferably the case because, on the one hand, this prevents the unburned hydrocarbons from being blown out into the environment with the normal exhaust gas flow, and it also prevents the scavenging pump from having to work counter to the exhaust gas flow. As a result, the scavenging pump can be made smaller. It is also advantageous if the scavenging pump sucks in fresh air from the environment and conveys it through the storage catalytic converter in the opposite direction to the usual main flow direction of the exhaust gas.
Frischluft aus der Umgebung ist vorteilhaft, da diese in aller Regel eine deutlich geringere Konzentration an Kohlenwasserstoffen aufweisen wird, so dass ein deutliches Konzentrationsgefälle zwischen dem Speicherkatalysator und dem Frischluftstrom vorherrschen wird. Dies begünstigt das Auslösen der Kohlenwasserstoffe aus dem Katalysator in den Luftstrom hinein. Fresh air from the environment is advantageous because it will generally have a significantly lower concentration of hydrocarbons, so that there will be a significant concentration gradient between the storage catalytic converter and the fresh air flow. This favors the release of the hydrocarbons from the catalyst into the air stream.
Ein bevorzugtes Ausführungsbeispiel ist dadurch gekennzeichnet, dass die im Speicherbehälter gespeicherten Kohlenwasserstoffe zu einem definierten Zeitpunkt in die Brennkammer der Verbrennungskraftmaschine abgegeben werden. A preferred exemplary embodiment is characterized in that the hydrocarbons stored in the storage container are released into the combustion chamber of the internal combustion engine at a defined point in time.
Der Speicherbehälter ist dazu ausgelegt, die Kohlenwasserstoffe aus dem durch den Speicherbehälter geleiteten Luftstrom herauszulösen. Hierzu kann ein Bindemittel im Speicherbehälter, beispielsweise Aktivkohle, vorgesehen sein. Der Speicherbehälter bevorratet die ausgelösten Kohlenwasserstoffe dann für eine gewissen Zeit. Zu günstigen Zeitpunkten, können die im Speicherbehälter aufgefangenen Kohlenwasserstoffe dann wieder der Verbrennung in der Verbrennungskraftmaschine zugeführt werden. Somit wird verhindert, dass unverbrannten Kohlenwasserstoffe in die Umgebung austreten und so zu einer unerwünschten Umweltbelastung führen. The storage canister is designed to strip the hydrocarbons from the airflow directed through the storage canister. For this purpose, a binder can be provided in the storage container, for example activated carbon. The storage tank then stores the released hydrocarbons for a certain time. At favorable points in time, the hydrocarbons collected in the storage container can then be returned to the combustion in the internal combustion engine. This prevents unburned hydrocarbons from escaping into the environment and thus leading to undesirable environmental pollution.
Auch ist es zu bevorzugen, wenn der durch den Speicherkatalysator geleitetet Frischluftstrom aufgrund der Konzentrationsunterschiede von Kohlenwasserstoffen zwischen der Frischluft und dem Speicherkatalysator mit im Speicherkatalysator befindlichen Kohlenwasserstoffen angereichert wird. It is also preferable if the fresh air flow conducted through the storage catalytic converter is enriched with hydrocarbons present in the storage catalytic converter due to the differences in concentration of hydrocarbons between the fresh air and the storage catalytic converter.
Darüber hinaus ist es vorteilhaft, wenn durch zumindest ein Regelventil der von der Spülpumpe erzeugte Frischluftstrom lenkbar ist, wobei das Regelventil Strömungswege zum Speicherkatalysator und/oder zu einem Kraftstofftank freigibt oder verschließt. Je nach Aufbau des Systems, kann die Spülpumpe neben dem erfindungsgemäßen Zweck auch dafür verwendet werden gelöste Kohlenwasserstoffe aus dem Kraftstofftank abzuleiten, oder andere Systeme mit einem Luftstrom zu versorgen. Um einen jeweils für den entsprechenden Anwendungsfall passenden Luftstrom zu erzeugen ist das Vorsehen von Regelventilen vorteilhaft. In addition, it is advantageous if the fresh air flow generated by the scavenging pump can be steered by at least one control valve, with the control valve opening or closing flow paths to the storage catalytic converter and/or to a fuel tank. Depending on the structure of the system, the scavenging pump can, in addition to the purpose according to the invention, also be used to drain dissolved hydrocarbons from the fuel tank or to supply other systems with an air flow. The provision of control valves is advantageous in order to generate an air flow that is suitable in each case for the corresponding application.
Bevorzugt ist der Speicherbehälter derart ausgelegt, dass es Kohlenwasserstoffe aus mehreren Anwendungen, beispielsweise aus dem Kraftstofftank und dem Speicherkatalysator, Zwischenspeichern kann. The storage container is preferably designed in such a way that it can temporarily store hydrocarbons from a number of applications, for example from the fuel tank and the storage catalytic converter.
Die Aufgabe hinsichtlich der Vorrichtung wird durch eine Vorrichtung mit den Merkmalen von Anspruch 6 gelöst. The object with regard to the device is solved by a device having the features of claim 6 .
Ein Ausführungsbeispiel der Erfindung betrifft eine Vorrichtung zum Auslösen von Kohlenwasserstoffen aus einem Speicherkatalysator für Kohlenwasserstoffe, wobei die Vorrichtung eine Strömungsstrecke für Abgase einer Verbrennungskraftmaschine aufweist, in welcher der Speicherkatalysator angeordnet ist, wobei eine Spülpumpe vorgesehen ist, welche dazu eingerichtet ist, einen Frischluftstrom durch den Speicherkatalysator hin zu einem Speicherbehälter zu führen. One exemplary embodiment of the invention relates to a device for releasing hydrocarbons from a storage catalytic converter for hydrocarbons, the device having a flow path for exhaust gases from an internal combustion engine, in which the storage catalytic converter is arranged, with a scavenging pump being provided which is designed to direct a flow of fresh air through the To lead storage catalyst towards a storage container.
Weiterhin ist es vorteilhaft, wenn der Speicherbehälter ein Bindemittel zur Auslösung der im von der Spülpumpe erzeugten Luftstrom enthaltenen Kohlenwasserstoffe aufweist. Ein solches Bindemittel kann beispielsweise eine Aktivkohle sein, die die im Luftstrom mitgeführten freien Kohlenwasserstoffe, die beispielsweise als feine Tröpfchen vorliegen können, zu binden und aus dem Luftstrom zu entfernen. Furthermore, it is advantageous if the storage container has a binder for releasing the hydrocarbons contained in the air flow generated by the scavenging pump. Such a binder can be, for example, activated carbon, which binds the free hydrocarbons entrained in the air stream, which can be present, for example, as fine droplets, and removes them from the air stream.
Auch ist es zweckmäßig, wenn die Spülpumpe ebenfalls dazu eingerichtet ist gasförmige Kohlenwasserstoffe aus einem Kraftstofftank auszuspülen. Bevorzugt wird die Spülpumpe verwendet, die bereits zur Entlüftung des Kraftstofftanks genutzt wird, da dadurch die Systemkosten insgesamt niedrig gehalten werden können und lediglich zusätzliche Leitungen und Ventile vorgesehen werden müssen, um den Luftstrom zum Speicherkatalysator und vom Speicherkatalysator in den Speicherbehälter und gegebenenfalls vom Speicherbehälter in den Ansaugtrakt zu leiten. It is also expedient if the scavenging pump is also set up to flush gaseous hydrocarbons out of a fuel tank. Preference is given to using the scavenging pump that is already being used to vent the fuel tank, since this allows the overall system costs to be kept low and only additional lines and valves have to be provided to allow the air flow to the storage catalytic converter and from the storage catalytic converter into the Storage container and, if necessary, to conduct from the storage container in the intake tract.
Darüber hinaus ist es vorteilhaft, wenn zumindest ein Regelventil vorgesehen ist, welches dazu eingerichtet ist, den von der Spülpumpe erzeugten Frischluftstrom entweder durch den Kraftstofftank in den Speicherbehälter oder durch den Speicherkatalysator in den Speicherbehälter zu führen. Auf diese Weise kann die Spülpumpe für mehrere Applikationen verwendet werden, wodurch der Hardwareaufwand reduziert wird und somit die Vorrichtung kostengünstiger wird. In addition, it is advantageous if at least one control valve is provided, which is set up to direct the fresh air flow generated by the scavenging pump either through the fuel tank into the storage tank or through the storage catalytic converter into the storage tank. In this way, the scavenging pump can be used for a number of applications, as a result of which the outlay on hardware is reduced and the device is therefore more cost-effective.
Vorteilhafte Weiterbildungen der vorliegenden Erfindung sind in den Unteransprüchen und in der nachfolgenden Figurenbeschreibung beschrieben. Advantageous developments of the present invention are described in the dependent claims and in the following description of the figures.
Kurze Beschreibung der Zeichnungen Brief description of the drawings
Im Folgenden wird die Erfindung anhand von einem Ausführungsbeispiel unter Bezugnahme auf die Zeichnung detailliert erläutert. In der Zeichnung zeigt: The invention is explained in detail below using an exemplary embodiment with reference to the drawing. In the drawing shows:
Fig. 1 eine schematische Ansicht eines Abgastrakts mit einem Speicherkatalysator, einer Spülpumpe, einem Speicherbehälter. 1 shows a schematic view of an exhaust system with a storage catalytic converter, a scavenging pump, and a storage tank.
Bevorzugte Ausführung der Erfindung Preferred embodiment of the invention
Die Figur 1 zeigt eine schematische Ansicht einer Vorrichtung 1 zur Spülung eines Speicherkatalysators 3. Der Speicherkatalysator 3 ist in einem Abgastrakt 2 einer Verbrennungskraftmaschine 9 installiert und dient zur Speicherung von unverbrannten Kohlenwasserstoffen im Abgas, welches entlang der durch den Pfeil 4 markierten Richtung durch den Abgastrakt 2 strömbar ist. Speicherkatalysatoren 3 und deren Funktionsweise sind im Stand der Technik bekannt. Bevorzugt ist der Speicherkatalysator 3 als metallisches Substrat mit einer entsprechenden Beschichtung aufgebaut. Figure 1 shows a schematic view of a device 1 for flushing a storage catalytic converter 3. The storage catalytic converter 3 is installed in an exhaust tract 2 of an internal combustion engine 9 and is used to store unburned hydrocarbons in the exhaust gas, which flows through the exhaust tract along the direction marked by arrow 4 2 is flowable. Storage catalysts 3 and how they work are known in the prior art. The storage catalytic converter 3 is preferably constructed as a metallic substrate with a corresponding coating.
In Strömungsrichtung 4 können dem Speicherkatalysator 3 weitere Komponenten zur Abgasnachbehandlung nachgelagert sein. Besonders vorteilhaft ist es, den Speicherkatalysator 3 in der Nähe des Unterbodens des Fahrzeugs einzusetzen. Im Falle einer Anordnung am oder in der Nähe des Unterbodens, ist die Anordnung des Drei-Wege-Katalysators in kurzer Entfernung zur Verbrennungskraftmaschine 9 zu bevorzugen, um insbesondere auch die schnell erreichten hohen Temperaturen direkt nach der Verbrennungskraftmaschine 9 im Falle eines Kaltstarts zu nutzen. In flow direction 4, further components for exhaust gas aftertreatment can be arranged downstream of storage catalytic converter 3. It is particularly advantageous to use the storage catalytic converter 3 in the vicinity of the underbody of the vehicle. In the case of an arrangement on or near the underbody, the arrangement of the three-way catalytic converter at a short distance from the internal combustion engine 9 is preferable, in particular in order to use the quickly reached high temperatures directly after the internal combustion engine 9 in the event of a cold start.
Mit dem Bezugszeichen 5 ist eine Spülpumpe dargestellt, die einen Luftstrom erzeugen kann. Bevorzugt wird hier Frischluft aus der Umgebung angesaugt. Der Luftstrom durchströmt dann den Speicherkatalysator 3 entgegen der Hauptdurchströmungsrichtung 4 des Abgastrakts 2. Im Speicherkatalysator 3 nimmt der Luftstrom die Kohlenwasserstoffe auf und strömt entlang einer Abführleitung 7 aus dem Abgastrakt 2 hinaus. Entlang der Spülpumpe 5 strömt der Luftstrom in den Speicherbehälter 6 in welchem die im Luftstrom mitgeführten Kohlenwasserstoffe in der durchströmten Aktivkohle gebunden werden. Der Luftstrom strömt sodann über eine Ausführleitung 11 in die Umgebung aus. Die im Speicherbehälter 6 gespeicherten Kohlenwasserstoffe können entlang der Zuführleitung 8 erneut der Verbrennungskraftmaschine zugeführt werden. A scavenging pump, which can generate an air flow, is identified by the reference number 5 . Fresh air from the environment is preferably sucked in here. The air flow then flows through the storage catalytic converter 3 counter to the main flow direction 4 of the exhaust tract 2 . In the storage catalytic converter 3 the air flow absorbs the hydrocarbons and flows out of the exhaust tract 2 along a discharge line 7 . The air stream flows along the scavenging pump 5 into the storage container 6 in which the hydrocarbons entrained in the air stream are bound in the activated carbon that flows through. The air stream then flows out into the environment via a discharge line 11 . The hydrocarbons stored in the storage tank 6 can be fed back to the internal combustion engine along the feed line 8 .
In der Zuführleitung 8 und/oder der Abführleitung 7 können zusätzlich Regelventile vorgesehen werden, die den Luftstrom steuern. Dies ist insbesondere dann vorteilhaft, wenn die Spülpumpe 5 beispielsweise auch dazu eingesetzt wird, den Kraftstofftank 10 zu entlüften beziehungsweise die dort oberhalb des Kraftstoffspiegels befindlichen Kohlenwasserstoffe auszuspülen. Die Spülpumpe 5 und der Speicherbehälter 6 können dann für beide Zwecke verwendet werden. In addition, control valves that control the air flow can be provided in the supply line 8 and/or the discharge line 7 . This is particularly advantageous when the scavenging pump 5 is also used, for example, to vent the fuel tank 10 or to flush out the hydrocarbons located above the fuel level there. The flushing pump 5 and the storage tank 6 can then be used for both purposes.
Die Figur 1 zeigt zur Ergänzung der Erfindung einen Kraftstofftank 10, welcher über eine Verbindungsleitung 12 mit dem Speicherbehälter 6 verbunden ist. Das Ausführungsbeispiel der Figur 1 weist insbesondere keinen beschränkenden Charakter auf und dient der Verdeutlichung des Erfindungsgedankens. To supplement the invention, FIG. 1 shows a fuel tank 10 which is connected to the storage tank 6 via a connecting line 12 . In particular, the exemplary embodiment in FIG. 1 has no restrictive character and serves to clarify the idea of the invention.

Claims

9 Patentansprüche 9 patent claims
1. Verfahren zur Reduzierung von Kohlenwasserstoffen in einem Speicherkatalysator (3) für Kohlenwasserstoffe, wobei der Speicherkatalysator (3) in einem Abgastrakt (2) einer Verbrennungskraftmaschine (9) angeordnet ist und dazu eingerichtet ist unverbrannte Kohlenwasserstoffe aus dem Abgasstrom aufzunehmen, wobei eine Spülpumpe (5) vorgesehen ist, welcher dazu eingerichtet ist einen Frischluftstrom durch den Speicherkatalysator (3) zu leiten und die hierdurch aus dem Speicherkatalysator (3) ausgelösten Kohlenwasserstoffe in einem Speicherbehälter (6) für Kohlenwasserstoffe zwischenzuspeichern, wobei durch das Verfahren ein von einem Abgasstrom im Abgastrakt (2) unabhängiger Luftstrom erzeugt wird und durch den Speicherkatalysator (3) geleitet wird und anschließend durch einen Speicherbehälter (6) geleitet wird. 1. A method for reducing hydrocarbons in a storage catalytic converter (3) for hydrocarbons, the storage catalytic converter (3) being arranged in an exhaust tract (2) of an internal combustion engine (9) and being set up to absorb unburned hydrocarbons from the exhaust gas stream, a scavenging pump ( 5) is provided, which is set up to conduct a flow of fresh air through the storage catalytic converter (3) and to temporarily store the hydrocarbons released as a result from the storage catalytic converter (3) in a storage container (6) for hydrocarbons, with the method using one of an exhaust gas flow in the exhaust tract (2) independent air flow is generated and passed through the storage catalyst (3) and then passed through a storage tank (6).
2. Verfahren nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t , dass der Frischluftstrom durch den Speicherkatalysator (3) geleitet wird, während die Verbrennungskraftmaschine (9) nicht betrieben wird. 2. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that the fresh air flow is passed through the storage catalyst (3) while the internal combustion engine (9) is not operated.
3. Verfahren nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , dass die Spülpumpe (5) Frischluft aus der Umgebung ansaugt und entgegen der gewöhnlichen Hauptströmungsrichtung (4) des Abgases durch den Speicherkatalysator (3) fördert. 3. The method according to any one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the scavenging pump (5) draws in fresh air from the environment and conveys it through the storage catalytic converter (3) counter to the usual main flow direction (4) of the exhaust gas.
4. Verfahren nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , dass die im Speicherbehälter (6) gespeicherten Kohlenwasserstoffe zu einem definierten Zeitpunkt in die Brennkammer der Verbrennungskraftmaschine (9) abgegeben werden. 4. The method according to any one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the hydrocarbons stored in the storage container (6) are released into the combustion chamber of the internal combustion engine (9) at a defined point in time.
5. Verfahren nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , dass der durch den Speicherkatalysator (3) geleitetet Frischluftstrom aufgrund der Konzentrationsunterschiede von Kohlenwasserstoffen zwischen der Frischluft und dem Speicherkatalysator (3) mit im Speicherkatalysator (3) befindlichen Kohlenwasserstoffen angereichert wird. Verfahren nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , dass durch zumindest ein Regelventil der von der Spülpumpe (5) erzeugte Frischluftstrom lenkbar ist, wobei das Regelventil Strömungswege zum Speicherkatalysator (3) und/oder zu einem Kraftstofftank (10) freigibt oder verschließt. Vorrichtung zum Auslösen von Kohlenwasserstoffen aus einem Speicherkatalysator (3) für Kohlenwasserstoffe, wobei die Vorrichtung eine Strömungsstrecke für Abgase einer Verbrennungskraftmaschine (9) aufweist, in welcher der Speicherkatalysator (3) angeordnet ist, wobei eine Spülpumpe (5) vorgesehen ist, welche dazu eingerichtet ist, einen Frischluftstrom durch den Speicherkatalysator (3) hin zu einem Speicherbehälter (6) zu führen. Vorrichtung nach Anspruch 7, d a d u r c h g e k e n n z e i c h n e t , dass der Speicherbehälter (6) ein Bindemittel zur Auslösung der im von der Spülpumpe (5) erzeugten Luftstrom enthaltenen Kohlenwasserstoffe aufweist. Verfahren nach einem der vorhergehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t , dass die Spülpumpe (5) ebenfalls dazu eingerichtet ist gasförmige Kohlenwasserstoffe aus einem Kraftstofftank (10) auszuspülen. Verfahren nach Anspruch 9, d a d u r c h g e k e n n z e i c h n e t , dass zumindest ein Regelventil vorgesehen ist, welches dazu eingerichtet ist, den von der Spülpumpe (5) erzeugten Frischluftstrom entweder durch den Kraftstofftank (10) in den Speicherbehälter (6) oder durch den Speicherkatalysator (3) in den Speicherbehälter (6) zu führen. 5. The method according to any one of the preceding claims, characterized in that through the storage catalyst (3) conducted fresh air flow due to the concentration differences of hydrocarbons between the fresh air and the storage catalyst (3) is enriched with hydrocarbons present in the storage catalytic converter (3). Method according to one of the preceding claims, characterized in that the fresh air flow generated by the scavenging pump (5) can be steered by at least one control valve, the control valve opening or closing flow paths to the storage catalytic converter (3) and/or to a fuel tank (10). Device for releasing hydrocarbons from a storage catalytic converter (3) for hydrocarbons, the device having a flow path for exhaust gases from an internal combustion engine (9), in which the storage catalytic converter (3) is arranged, a scavenging pump (5) being provided which is set up for this purpose is to direct a flow of fresh air through the storage catalytic converter (3) to a storage container (6). Device according to Claim 7, characterized in that the storage container (6) has a binding agent for releasing the hydrocarbons contained in the air flow generated by the scavenging pump (5). Method according to one of the preceding claims, characterized in that the flushing pump (5) is also set up to flush out gaseous hydrocarbons from a fuel tank (10). Method according to Claim 9, characterized in that at least one control valve is provided which is set up to direct the fresh air flow generated by the scavenging pump (5) either through the fuel tank (10) into the storage container (6) or through the storage catalytic converter (3) into the To lead storage container (6).
PCT/EP2021/083807 2020-12-17 2021-12-01 Method for cleaning a storage catalyst, and corresponding device WO2022128481A1 (en)

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EP0747581A1 (en) * 1995-06-06 1996-12-11 Johnson Matthey Public Limited Company Improvements in emissions control
WO1996039576A1 (en) * 1995-06-06 1996-12-12 Johnson Matthey Public Limited Company Combatting air pollution
GB2340054A (en) * 1998-07-24 2000-02-16 Johnson Matthey Plc Combatting air pollution

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DE102009020789A1 (en) 2008-06-26 2009-12-31 Ford Global Technologies, LLC, Dearborn Hydrocarbon retaining and purging system for vehicle, has controller selectively routing fuel vapors from fuel system to hydrocarbon retaining system and selectively purging stored hydrocarbons from retaining system to engine intake
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EP0747581A1 (en) * 1995-06-06 1996-12-11 Johnson Matthey Public Limited Company Improvements in emissions control
WO1996039576A1 (en) * 1995-06-06 1996-12-12 Johnson Matthey Public Limited Company Combatting air pollution
GB2340054A (en) * 1998-07-24 2000-02-16 Johnson Matthey Plc Combatting air pollution

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