WO2001077507A1 - Method for the desulphurisation of an oxidation catalyst arranged in the exhaust line of a diesel internal combustion engine - Google Patents

Method for the desulphurisation of an oxidation catalyst arranged in the exhaust line of a diesel internal combustion engine Download PDF

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Publication number
WO2001077507A1
WO2001077507A1 PCT/EP2001/003739 EP0103739W WO0177507A1 WO 2001077507 A1 WO2001077507 A1 WO 2001077507A1 EP 0103739 W EP0103739 W EP 0103739W WO 0177507 A1 WO0177507 A1 WO 0177507A1
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Prior art keywords
internal combustion
exhaust gas
combustion engine
diesel internal
gas temperature
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PCT/EP2001/003739
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German (de)
French (fr)
Inventor
Henning Loerch
Kurt Bluhm
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Audi Ag
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Priority to JP2001574739A priority Critical patent/JP2003531991A/en
Priority to EP01936171A priority patent/EP1268998A1/en
Publication of WO2001077507A1 publication Critical patent/WO2001077507A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus

Definitions

  • the present invention relates to a method for desulfurization of an oxidation catalytic converter arranged in the exhaust line of a diesel internal combustion engine.
  • Oxidation catalysts of this type are used in diesel internal combustion engines in order to enable the low-temperature regeneration of a soot filter connected in the exhaust line by the oxidation of nitrogen oxides.
  • the task is solved by operating the diesel internal combustion engine to desulfurize the oxidation catalytic converter with a lambda value ⁇ 1 of approximately 0.98 to 0.99 and an exhaust gas temperature T1 of at least 350 ° C.
  • the exhaust gas generated in this way with a high content of carbon monoxide CO, hydrogen H 2 and hydrocarbon HC, spontaneously reduces the sulfates -SO 4 formed on the surface of the oxidation catalyst to sulfur dioxide SO 2 , so that the oxidation catalyst already has a reduced oxidation ability at moderate and thus practical exhaust gas temperatures in a maximum of three to four minutes.
  • the regeneration period can in principle also be the sum of several short "fat phases" which, for. B. lie in the second range can be achieved.
  • the method for desulfurization according to the invention it is thus possible to operate the diesel internal combustion engine at least temporarily with fuel containing sulfur, which is necessary, inter alia, when driving in countries without sulfur-free fuel. But even if the diesel internal combustion engine is operated exclusively with low-sulfur or sulfur-free fuel, the desulfurization process has a positive effect on the life of the oxidation catalytic converter.
  • Desulphurization of the oxidation catalyst is preferred at high load and low speed of the diesel engine, such as. B. during an acceleration process at full load and a speed of 1250 rpm. Because the lambda value required for the desulfurization process, which is only slightly below 1, is then available in some cases, depending on the type of diesel internal combustion engine, so that a slight additional enrichment of the air / fuel mixture may be necessary.
  • the intake air is expediently throttled to achieve the lambda value ⁇ 1 or the exhaust gas temperature T1. If this is not sufficient, then a speed-synchronous post-injection can also be carried out, the post-injection should take place at a maximum of 20 degrees after the main injection, so that the diesel internal combustion engine can nevertheless be operated largely soot-free.
  • the boost pressure can also be reduced in order to achieve the lambda value ⁇ 1 or the exhaust gas temperature T1.
  • low-soot operation of the diesel internal combustion engine should always be aimed for, in order to avoid an additional loading of the soot filter, if possible.
  • the process for desulfurization advantageously only runs when there is a regeneration request, the regeneration request being issued as a function of the degree of sulfurization of the oxidation catalyst.
  • the enrichment measures are not carried out unnecessarily if the oxidation capacity of the oxidation catalytic converter is still completely in order.
  • the degree of sulfurization of the oxidation catalytic converter is determined as a function of the operating hours, the fuel throughput and / or the exhaust gas temperature of the diesel internal combustion engine, assuming that the sulfur content in the fuel is known, then a reliable criterion for the maturity of a desulfurization process is given.
  • the figure shows a diesel internal combustion engine 1 with a schematically illustrated injection device 2.
  • the intake air passes through an intake Line 3 and an intake manifold 4 with built-in throttle 5 to the diesel internal combustion engine 1 and the exhaust gas passes through an exhaust gas line 6 to an exhaust gas turbocharger 7, an oxidation catalytic converter 8 and a soot filter 9.
  • an oxidation catalytic converter 8 there is also a lambda sensor 10 in the exhaust gas line 6 and a temperature sensor 11 are arranged.
  • a control device 12 is provided to control a desulfurization process, which is connected to the injection device 2, the throttle 5, the exhaust gas turbocharger 7 and the two sensors 10 and 11.
  • the control unit 12 In order to determine the degree of sulfurization of the oxidation catalytic converter 8, the control unit 12 continuously records the operating hours, the fuel throughput and the exhaust gas temperature of the diesel internal combustion engine 1 in addition to the lambda value. When an upper limit value is reached, the control unit 12 issues a regeneration request. Thereupon, depending on the operating point of the diesel internal combustion engine 1, the intake air is throttled by means of the throttle 5, post-injection is synchronized in terms of speed by means of the injection device 2 and / or the boost pressure is reduced by means of the exhaust gas turbocharger 7 in order to reduce the air required to desulfurize the oxidation catalytic converter 8. / Fuel ratio ⁇ 1 from 0.98 to 0.99 and an exhaust gas temperature T1 of at least 350 ° C.
  • the sulfates formed on the surface of the oxidation catalytic converter 8 are e.g. B. per
  • the oxidation catalytic converter 8 can again adequately oxidize the nitrogen oxides

Abstract

A method for the desulphurisation of an oxidation catalyst (8), arranged in the exhaust line of a diesel internal combustion engine (1), is disclosed, whereby the diesel internal combustion engine (1) is operated at a lambda value μ1 of ca. 0.98 to 0.99 and an exhaust gas temperature T1 of at least 350 °C. The oxidative capacity of the oxidation catalyst impaired by sulphur is thus regenerated within a short period and at moderate exhaust temperatures. Diesel internal combustion engines can thus, at least temporarily, be operated using sulphur containing fuel.

Description

Verfahren zur Entschwefelung eines im Abgasstrang einer Diesel- Brennkraftmaschine angeordneten Oxidationskatalysators Process for the desulfurization of an oxidation catalytic converter arranged in the exhaust line of a diesel internal combustion engine
B E S C H R E I B U N GDESCRIPTION
Die vorliegende Erfindung betrifft ein Verfahren zur Entschwefelung eines im Abgasstrang einer Diesel-Brennkraftmaschine angeordneten Oxidationskatalysators. Solche Oxidationskatalysatoren werden bei Diesel-Brennkraftmaschinen eingesetzt, um durch die Oxidation von Stickoxiden die Tieftem- peraturregeneration eines im Abgasstrang nachgeschalteten Rußfilters zu ermöglichen.The present invention relates to a method for desulfurization of an oxidation catalytic converter arranged in the exhaust line of a diesel internal combustion engine. Oxidation catalysts of this type are used in diesel internal combustion engines in order to enable the low-temperature regeneration of a soot filter connected in the exhaust line by the oxidation of nitrogen oxides.
In Verbindung mit der Entschwefelung von NOx-Speicherkatalysatoren ist es bekannt, Diesel-Brennkraftmaschinen bei einem Luft-/Kraftstoffverhältnis Lambda, das deutlich unterhalb von 1 liegt, und bei einer Abgastemperatur, die oberhalb von 550° C liegt, zu betreiben. Die Entschwefelung von NOx- Speicherkatalysatoren zur Wiederherstellung von deren Speicherfähigkeit für NOx benötigt jedoch relativ lange.In connection with the desulfurization of NO x storage catalytic converters, it is known to operate diesel internal combustion engines at an air / fuel ratio lambda that is significantly below 1 and at an exhaust gas temperature that is above 550 ° C. However, the desulfurization of NO x storage catalysts to restore their storage capacity for NO x takes a relatively long time.
Dagegen ist die Entschwefelung von Oxidationskatalysatoren zur Wiederherstellung von deren Oxidationsfähigkeit aber noch wesentlich problematischer. Denn der Versuch, Oxidationskatalysatoren durch hohe Temperaturen, hohe Lasten sowie hohe Drehzahlen von dem in Form von Sulfaten auf der Oberfläche gebundenen Schwefel zu befreien, ergab eine nur unzureichende Entschwefelung. Außerdem besteht bei einem derartigen Vorgehen aufgrund der hohen Temperaturen die Gefahr einer thermischen Schädigung der Oxidationskatalysatoren.In contrast, the desulfurization of oxidation catalysts to restore their oxidation ability is still much more problematic. The attempt to free oxidation catalysts from the sulfur bound in the form of sulfates on the surface by high temperatures, high loads and high speeds resulted in insufficient desulfurization. In addition, due to the high temperatures, there is a risk of thermal damage to the oxidation catalysts in such a procedure.
Demzufolge ist man bisher darauf angewiesen, eine Diesel-Brennkraftmaschine nur mit schwefelarmem bzw. schwefelfreiem Kraftstoff zu betreiben, um die Regeneration eines dem Oxidationskatalysator nachgeschalte- ten Rußfilters zu ermöglichen und somit ein Liegenbleiben der Diesel- Brennkraftmaschine zu vermeiden. Ausgehend von diesem Stand der Technik ist es Aufgabe der vorliegenden Erfindung, ein Verfahren zur Entschwefelung eines im Abgasstrang der Diesel-Brennkraftmaschine angeordneten Oxidationskatalysators bereitzustellen, welches eine erheblich verbesserte Entschwefelung ermöglicht, ohne dass dabei die Gefahr einer thermischen Schädigung des Oxidationskatalysators besteht.Accordingly, it has hitherto been necessary to operate a diesel internal combustion engine only with low-sulfur or sulfur-free fuel in order to enable the regeneration of a soot filter downstream of the oxidation catalytic converter and thus to prevent the diesel internal combustion engine from stopping. Starting from this prior art, it is an object of the present invention to provide a method for desulfurization of an oxidation catalytic converter arranged in the exhaust line of the diesel internal combustion engine, which enables considerably improved desulfurization without the risk of thermal damage to the oxidation catalytic converter.
Gelöst wird die Aufgabe, indem die Diesel-Brennkraftmaschine zur Entschwefelung des Oxidationskatalysators bei einem Lambdawert λ1 von ca. 0,98 bis 0,99 und einer Abgastemperatur T1 von mindestens 350°C betrieben wird. Durch das so erzeugte Abgas mit einem hohem Gehalt an Koh- lenmonoxid CO, Wasserstoff H2 und Kohlenwasserstoff HC werden die an der Oberfläche des Oxidationskatalysators gebildeten Sulfate -SO4 spontan zu Schwefeldioxid SO2 reduziert, so dass eine verminderte Oxidationsfähig- keit des Oxidationskatalysators bereits bei moderaten und damit praxistauglichen Abgastemperaturen in maximal drei bis vier Minuten wieder hergestellt wird. Dabei kann die Regenerationsdauer grundsätzlich auch aus der Summe mehrerer kurzer "Fettphasen", die z. B. im Sekundenbereich liegen, erreicht werden. Dank des erfindungsgemäßen Verfahrens zur Entschwefelung ist es somit möglich, die Diesel-Brennkraftmaschine zumindest vorübergehend mit schwefelhaltigem Kraftstoff zu betreiben, was unter anderem bei Fahrten in Ländern ohne schwefelfreien Kraftstoff erforderlich ist. Aber selbst dann, wenn die Diesel-Brennkraftmaschine ausschließlich mit schwefelarmem bzw. schwefelfreiem Kraftstoff betrieben wird, hat das Verfahren zur Entschwefelung ein positive Auswirkung auf die Lebensdauer des Oxidationskatalysators.The task is solved by operating the diesel internal combustion engine to desulfurize the oxidation catalytic converter with a lambda value λ1 of approximately 0.98 to 0.99 and an exhaust gas temperature T1 of at least 350 ° C. The exhaust gas generated in this way, with a high content of carbon monoxide CO, hydrogen H 2 and hydrocarbon HC, spontaneously reduces the sulfates -SO 4 formed on the surface of the oxidation catalyst to sulfur dioxide SO 2 , so that the oxidation catalyst already has a reduced oxidation ability at moderate and thus practical exhaust gas temperatures in a maximum of three to four minutes. The regeneration period can in principle also be the sum of several short "fat phases" which, for. B. lie in the second range can be achieved. Thanks to the method for desulfurization according to the invention, it is thus possible to operate the diesel internal combustion engine at least temporarily with fuel containing sulfur, which is necessary, inter alia, when driving in countries without sulfur-free fuel. But even if the diesel internal combustion engine is operated exclusively with low-sulfur or sulfur-free fuel, the desulfurization process has a positive effect on the life of the oxidation catalytic converter.
Bevorzugt wird die Entschwefelung des Oxidationskatalysators bei hoher Last und geringer Drehzahl der Diesel-Brennkraftmaschine, wie z. B. während eines Beschleunigungsvorgangs bei Volllast und einer Drehzahl von 1250 U/min vorgenommen. Denn der für den Entschwefelungsvorgang benötigte, nur geringfügig unterhalb von 1 liegende Lambdawert steht je nach Typ der Diesel-Brennkraftmaschine dann teilweise ohnehin zur Verfügung, so dass allenfalls noch eine geringe zusätzliche Anfettung des Luft/Kraftstoffgemisches erforderlich ist.Desulphurization of the oxidation catalyst is preferred at high load and low speed of the diesel engine, such as. B. during an acceleration process at full load and a speed of 1250 rpm. Because the lambda value required for the desulfurization process, which is only slightly below 1, is then available in some cases, depending on the type of diesel internal combustion engine, so that a slight additional enrichment of the air / fuel mixture may be necessary.
Zweckmäßig wird zum Erreichen des Lambdawerts λ1 bzw. der Abgastemperatur T1 eine Drosselung der Ansaugluft vorgenommen. Reicht dies nicht aus, so kann außerdem eine drehzahlsynchrone Nacheinspritzung vorgenommen werden, wobei die Nacheinspritzung maximal 20 Grad nach der Haupteinspritzung erfolgen sollte, damit die Diesel- Brennkraftmaschine dennoch weitgehend rußarm betrieben werden kann.The intake air is expediently throttled to achieve the lambda value λ1 or the exhaust gas temperature T1. If this is not sufficient, then a speed-synchronous post-injection can also be carried out, the post-injection should take place at a maximum of 20 degrees after the main injection, so that the diesel internal combustion engine can nevertheless be operated largely soot-free.
Zusätzlich oder alternativ zu der Nacheinspritzung kann auch eine Absenkung des Ladedrucks vorgenommen werden, um den Lambdawert λ1 bzw. die Abgastemperatur T1 zu erreichen.In addition or as an alternative to the post-injection, the boost pressure can also be reduced in order to achieve the lambda value λ1 or the exhaust gas temperature T1.
Bei all diesen Maßnahmen zur Anfettung sollte stets ein rußarmer Betrieb der Diesel-Brennkraftmaschine angestrebt werden, um eine zusätzliche Beladung des Rußfilters - wenn möglich - zu vermeiden.With all these enrichment measures, low-soot operation of the diesel internal combustion engine should always be aimed for, in order to avoid an additional loading of the soot filter, if possible.
Vorteilhaft läuft das Verfahren zur Entschwefelung nur beim Vorliegen einer Regenerationsanforderung ab, wobei die Regenerationsanforderung in Abhängigkeit vom Verschwefelungsgrad des Oxidationskatalysators ausgegeben wird. Dadurch werden die Maßnahmen zur Anfettung nicht unnötig vorgenommen, wenn die Oxidationsfähigkeit des Oxidationskatalysators noch völlig in Ordnung ist.The process for desulfurization advantageously only runs when there is a regeneration request, the regeneration request being issued as a function of the degree of sulfurization of the oxidation catalyst. As a result, the enrichment measures are not carried out unnecessarily if the oxidation capacity of the oxidation catalytic converter is still completely in order.
Wird der Verschwefelungsgrad des Oxidationskatalysators als Funktion der Betriebsstunden, des Kraftstoffdurchsatzes und/oder der Abgastemperatur der Diesel-Brennkraftmaschine ermittelt, wobei vorausgesetzt wird, dass der Schwefelgehalt im Kraftstoff bekannt ist, so ist ein zuverlässiges Kriterium für die Fälligkeit eines Entschwefelungsvorgangs gegeben.If the degree of sulfurization of the oxidation catalytic converter is determined as a function of the operating hours, the fuel throughput and / or the exhaust gas temperature of the diesel internal combustion engine, assuming that the sulfur content in the fuel is known, then a reliable criterion for the maturity of a desulfurization process is given.
Wird außerdem die Zeit ermittelt, während der die Diesel-Brennkraftmaschine bei dem Lambdawert λ1 und oberhalb der Abgastemperatur T1 betrieben wird, so ist desweiteren ein Kriterium für den erfolgreichen Ab- schiuss eines Entschwefelungsvorgangs gegeben.If the time during which the diesel internal combustion engine is operated at the lambda value λ1 and above the exhaust gas temperature T1 is also determined, there is also a criterion for the successful completion of a desulfurization process.
Das Verfahren zur Entschwefelung eines im Abgasstrang einer Diesel- Brennkraftmaschine angeordneten Oxidationskatalysators wird anhand der nachfolgenden Figur näher erläutert.The method for desulfurization of an oxidation catalytic converter arranged in the exhaust line of a diesel engine is explained in more detail with reference to the following figure.
Die Figur zeigt eine Diesel-Brennkraftmaschine 1 mit einer schematisch dargestellten Einspritzeinrichtung 2. Die Ansaugluft gelangt über eine Ansaug- leitung 3 und ein Saugrohr 4 mit eingebauter Drossel 5 zu der Diesel- Brennkraftmaschine 1 und das Abgas gelangt über eine Abgasleitung 6 zu einem Abgasturbolader 7, einem Oxidationskatalysator 8 und einem Rußfilter 9. Vor dem Oxidationskatalysator 8 ist in der Abgasleitung 6 außerdem ein Lambdasensor 10 sowie ein Temperatursensor 11 angeordnet.The figure shows a diesel internal combustion engine 1 with a schematically illustrated injection device 2. The intake air passes through an intake Line 3 and an intake manifold 4 with built-in throttle 5 to the diesel internal combustion engine 1 and the exhaust gas passes through an exhaust gas line 6 to an exhaust gas turbocharger 7, an oxidation catalytic converter 8 and a soot filter 9. Before the oxidation catalytic converter 8 there is also a lambda sensor 10 in the exhaust gas line 6 and a temperature sensor 11 are arranged.
Darüber hinaus ist zur Steuerung eines Entschwefelungsvorgangs ein Steuergerät 12 vorgesehen, welches mit der Einspritzeinrichtung 2, der Drossel 5, dem Abgasturbolader 7 sowie den beiden Sensoren 10 und 11 in Verbindung steht.In addition, a control device 12 is provided to control a desulfurization process, which is connected to the injection device 2, the throttle 5, the exhaust gas turbocharger 7 and the two sensors 10 and 11.
Um den Verschwefelungsgrad des Oxidationskatalysators 8 zu ermitteln, erfasst das Steuergerät 12 neben dem Lambdawert auch fortlaufend die Betriebsstunden, den Kraftstoffdurchsatz und die Abgastemperatur der Diesel- Brennkraftmaschine 1. Beim Erreichen eines oberen Grenzwertes gibt das Steuergerät 12 eine Regenerationsanforderung aus. Daraufhin wird in Abhängigkeit vom Betriebspunkt der Diesel-Brennkraftmaschine 1 mittels der Drossel 5 eine Drosselung der Ansaugluft, mittels der Einspritzeinrichtung 2 eine drehzahlsynchrone Nacheinspritzung und/oder mittels des Abgasturboladers 7 eine Absenkung des Ladedrucks vorgenommen, um ein zur Entschwefelung des Oxidationskatalysators 8 erforderliches Luft-/Kraftstoffver- hältnis λ1 vom 0,98 bis 0,99 sowie eine Abgastemperatur T1 von mindestens 350°C zu erreichen.In order to determine the degree of sulfurization of the oxidation catalytic converter 8, the control unit 12 continuously records the operating hours, the fuel throughput and the exhaust gas temperature of the diesel internal combustion engine 1 in addition to the lambda value. When an upper limit value is reached, the control unit 12 issues a regeneration request. Thereupon, depending on the operating point of the diesel internal combustion engine 1, the intake air is throttled by means of the throttle 5, post-injection is synchronized in terms of speed by means of the injection device 2 and / or the boost pressure is reduced by means of the exhaust gas turbocharger 7 in order to reduce the air required to desulfurize the oxidation catalytic converter 8. / Fuel ratio λ1 from 0.98 to 0.99 and an exhaust gas temperature T1 of at least 350 ° C.
Ist der Lambdawert λ1 bzw. die Abgastemperatur T1 erreicht, so werden die an der Oberfläche des Oxidationskatalysators 8 gebildeten Sulfate z. B. perIf the lambda value λ1 or the exhaust gas temperature T1 is reached, the sulfates formed on the surface of the oxidation catalytic converter 8 are e.g. B. per
Al2 (SO4)3 + 3 H2 → AI2O3 + 3 SO2 + 3 H2OAl 2 (SO 4 ) 3 + 3 H 2 → AI 2 O 3 + 3 SO 2 + 3 H 2 O
spontan zu Schwefeldioxid reduziert. Dadurch kann der Oxidationskatalysator 8 wieder eine ausreichende Oxidation der Stickoxidespontaneously reduced to sulfur dioxide. As a result, the oxidation catalytic converter 8 can again adequately oxidize the nitrogen oxides
NO + O2 → NO2 NO + O 2 → NO 2
durchführen und können die oxidierten Stickoxide in Verbindung mit Ruß und Sauerstoff perperform and can the oxidized nitrogen oxides in connection with soot and oxygen per
NO2 + C + 1/a O2 → C02 + NO reagieren. Somit erfolgt schließlich eine Tieftemperaturregeneration des dem Oxidationskatalysator 8 nachgeschalteten Rußfilters 9.NO 2 + C + 1 / a O 2 → C0 2 + NO react. A low-temperature regeneration of the soot filter 9 downstream of the oxidation catalytic converter 8 thus finally takes place.
Das Steuergerät 12 erfasst außerdem die Zeit, während der der Lambdawert λ1 zwischen 0,98 und 0,99 und die Abgastemperatur oberhalb von T1 = 305°C liegt - also eine Regeneration des Oxidationskatalysators 8 durchgeführt wird. Nach dem Erreichen einer bestimmten Regenerationsdauer, welche das Erreichen eines unteren Grenzwertes des Verschwefelungsgrades des Oxidationskatalysators 8 impliziert, wird die Regenerationsanforderung wieder zurückgenommen und die Diesel-Brennkraftmaschine wieder normal betrieben. The control unit 12 also records the time during which the lambda value λ1 is between 0.98 and 0.99 and the exhaust gas temperature is above T1 = 305 ° C. - that is to say regeneration of the oxidation catalytic converter 8 is carried out. After a specific regeneration period has been reached, which implies that a lower limit of the degree of sulfurization of the oxidation catalytic converter 8 has been reached, the regeneration request is withdrawn again and the diesel internal combustion engine is operated normally again.

Claims

P A T E N T A N S P R Ü C H E PATENT CLAIMS
1. Verfahren zur Entschwefelung eines im Abgasstrang einer Diesel- Brennkraftmaschine angeordneten Oxidationskatalysators,1. Method for desulfurization of an oxidation catalytic converter arranged in the exhaust line of a diesel internal combustion engine,
dadurch gekennzeichnet, daßcharacterized in that
die Diesel-Brennkraftmaschine (1) bei einem Lambdawert λ1 von ca. 0,98 bis 0,99 und einer Abgastemperatur T1 von mindestens 350°C betrieben wird.the diesel internal combustion engine (1) is operated with a lambda value λ1 of approximately 0.98 to 0.99 and an exhaust gas temperature T1 of at least 350 ° C.
Verfahren nach Anspruch 1 , dadurch gekennzeichnet, dass die Entschwefelung bei hoher Last und geringer Drehzahl der Diesel- Brennkraftmaschine (1) vorgenommen wird.A method according to claim 1, characterized in that the desulfurization is carried out at high load and low speed of the diesel engine (1).
3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass zum Erreichen des Lambdawert.es λ1 bzw. der Abgastemperatur T1 eine Drosselung der Ansaugluft vorgenommen wird.3. The method according to claim 1 or 2, characterized in that the intake air is throttled to achieve the Lambda value λ1 or the exhaust gas temperature T1.
Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass zum Erreichen des Lambdawertes λ1 bzw. der Abgastemperatur T1 eine drehzahlsynchrone Nacheinspritzung vorgenommen wird.Method according to one of claims 1 to 3, characterized in that a speed-synchronous post-injection is carried out to reach the lambda value λ1 or the exhaust gas temperature T1.
5. Verfahren nach Anspruch 4, dadurch gekennzeichnet, dass die drehzahlsynchrone Nacheinspritzung maximal 20 Grad nach der Haupteinspritzung erfolgt. 5. The method according to claim 4, characterized in that the speed-synchronous post-injection takes place a maximum of 20 degrees after the main injection.
6. Verfahren nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass zum Erreichen des Lambdawertes λ1 bzw. der Abgastemperatur T1 eine Absenkung des Ladedrucks vorgenommen wird.6. The method according to any one of claims 1 to 5, characterized in that the boost pressure is reduced in order to reach the lambda value λ1 or the exhaust gas temperature T1.
7. Verfahren nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass die Entschwefelung beim Vorliegen einer Regenerationsanforderung vorgenommen wird, wobei die Regenerationsanforderung in Abhängigkeit vom Verschwefelungsgrad des Oxidationskatalysators (8) ausgegeben wird.7. The method according to any one of claims 1 to 6, characterized in that the desulfurization is carried out when there is a regeneration request, the regeneration request being issued as a function of the degree of sulfurization of the oxidation catalyst (8).
8. Verfahren nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass der Verschwefelungsgrad des Oxidationskatalysators (8) als Funktion der Betriebsstunden, des Kraftstoffdurchsatzes und/oder der Abgastemperatur der Diesel-Brennkraftmaschine (1) ermittelt wird.8. The method according to any one of claims 1 to 7, characterized in that the degree of sulfurization of the oxidation catalyst (8) is determined as a function of the operating hours, the fuel throughput and / or the exhaust gas temperature of the diesel engine (1).
Verfahren nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass die Zeit ermittelt wird, während der die Diesel-Brennkraftmaschine (1) bei einem Lambdawert λ1 und oberhalb einer Abgastemperatur T1 betrieben wird, um die Regenerationsanforderung nach dem Erreichen einer bestimmten Regenerationsdauer wieder zurückzunehmen. Method according to one of claims 1 to 8, characterized in that the time is determined during which the diesel internal combustion engine (1) is operated at a lambda value λ1 and above an exhaust gas temperature T1 in order to withdraw the regeneration request after a specific regeneration period has been reached ,
PCT/EP2001/003739 2000-04-06 2001-04-03 Method for the desulphurisation of an oxidation catalyst arranged in the exhaust line of a diesel internal combustion engine WO2001077507A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2001574739A JP2003531991A (en) 2000-04-06 2001-04-03 Method for sulfur desorption from oxidation catalyst mounted on exhaust pipe of diesel internal combustion engine
EP01936171A EP1268998A1 (en) 2000-04-06 2001-04-03 Method for the desulphurisation of an oxidation catalyst arranged in the exhaust line of a diesel internal combustion engine

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DE10017203.2 2000-04-06
DE10017203A DE10017203A1 (en) 2000-04-06 2000-04-06 Process for the desulfurization of an oxidation catalytic converter arranged in the exhaust line of a diesel internal combustion engine

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US (1) US20030051469A1 (en)
EP (1) EP1268998A1 (en)
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