DE3821345A1 - Device for reducing exhaust pollutants from an internal combustion engine - Google Patents

Device for reducing exhaust pollutants from an internal combustion engine

Info

Publication number
DE3821345A1
DE3821345A1 DE19883821345 DE3821345A DE3821345A1 DE 3821345 A1 DE3821345 A1 DE 3821345A1 DE 19883821345 DE19883821345 DE 19883821345 DE 3821345 A DE3821345 A DE 3821345A DE 3821345 A1 DE3821345 A1 DE 3821345A1
Authority
DE
Germany
Prior art keywords
catalyst
internal combustion
combustion engine
device
probe
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
DE19883821345
Other languages
German (de)
Inventor
Hans-Karl Dipl Ing Weining
Rudi Dipl Ing Klein
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daimler Benz AG
Original Assignee
Daimler Benz AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daimler Benz AG filed Critical Daimler Benz AG
Priority to DE19883821345 priority Critical patent/DE3821345A1/en
Publication of DE3821345A1 publication Critical patent/DE3821345A1/en
Application status is Withdrawn legal-status Critical

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust 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
    • F01N3/18Exhaust 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
    • F01N3/20Exhaust 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
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/008Mounting or arrangement of exhaust sensors in or on exhaust apparatus
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/02Circuit arrangements for generating control signals
    • F02D41/14Introducing closed-loop corrections
    • F02D41/1438Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1439Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the position of the sensor
    • F02D41/1441Plural sensors
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/02Circuit arrangements for generating control signals
    • F02D41/14Introducing closed-loop corrections
    • F02D41/1438Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1473Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method
    • F02D41/1474Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method by detecting the commutation time of the sensor
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2390/00Arrangements for controlling or regulating exhaust apparatus
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/02Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
    • F01N2560/025Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting O2, e.g. lambda sensors
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/14Exhaust systems with means for detecting or measuring exhaust gas components or characteristics having more than one sensor of one kind

Abstract

In its exhaust duct, an internal combustion engine has a catalytic converter and two oxygen sensors. The first sensor is arranged upstream of the converter and the second in the converter. The arrangement of these two sensors makes possible a high control frequency, taking into account the state of the catalytic converter and excluding hydrogen cross-sensitivity. In the catalytic converter arranged downstream of the second sensor, the exhaust gases detected by this sensor but not yet completely converted are converted so that nothing remains.

Description

Die Erfindung betrifft eine Vorrichtung zum Verringern von Abgas-Schadstoffkomponenten einer Brennkraftmaschine gemäß dem Oberbegriff des Patentanspruchs 1. The invention relates to a device for reducing pollutant components of exhaust gas of an internal combustion engine according to the preamble of claim 1.

Aus der DE-OS 32 24 347 ist eine Vorrichtung zum Verrin gern der Abgas-Schadstoffkomponenten einer Brennkraftma schine bekannt, die eine erste Sauerstoffsonde stromauf eines im Abgasweg der Brennkraftmaschine angeordneten Katalysators und eine zweite Sauerstoffsonde stromab des Katalysators aufweist. From DE-OS 32 24 347 a device for Verrin like the exhaust emission components of an Brennkraftma machine is known which comprises a first oxygen probe upstream of the exhaust path of the internal combustion engine arranged catalyst and a second oxygen sensor downstream of the catalyst. Um eine gute Regelung der Gemisch bildung mit einer hohen Regelfrequenz zu erhalten, muß die erste Sauerstoffsonde stromauf des Katalysators möglichst motornah angeordnet sein. To ensure a good control of the mixture to be obtained with a high control frequency formation, the first oxygen probe must be located close to the engine as possible upstream of the catalyst. Diese Lage der Sonde weist jedoch eine hohe Wasserstoffquerempfindlichkeit auf; However, this position of the probe has a high hydrogen cross sensitivity; das bedeutet, daß im Abgas der Brennkraftmaschine enthaltener freier Wasserstoff die Sondenkennlinie verschiebt und der Brennkraftmaschine ein nach mager verschobenes Gemisch zugeführt wird, wodurch der NO x -Gehalt im Abgas ansteigt. this means that in the exhaust gas of the internal combustion engine contained free hydrogen shifts the probe characteristics and the internal combustion engine is supplied a lean shifted by mixture, thereby increasing the NO x content in the exhaust gas. Um diesen Nachteil zu vermeiden und außerdem den von der ersten Sauerstoffsonde nicht erfaßten Zustand des Kataly sators zu berücksichtigen, wird in der DE-OS vorgeschla gen, eine zweite Sauerstoffsonde stromab des Katalysators anzuordnen. In order to avoid this drawback and also to take into account the not detected by the first oxygen sensor Kataly state of the crystallizer is gen pre schla in DE-OS, a second oxygen sensor downstream of the catalyst to arrange. Diese zweite Sonde weist keine Wasserstoff querempfindlichkeit mehr auf, da freier Wasserstoff im Katalysator zuvor oxidiert wird. This second probe has no hydrogen cross-sensitivity more, because free hydrogen is oxidized in the catalyst before.

Diese Anordnung weist den Nachteil auf, daß die Regelfre quenz, die bekanntlich durch die Gaslaufzeit, die Sonden erkennzeit, die Änderungszeit im Gemischbildner und den Gasdurchsatz, dh die Strömungsgeschwindigkeit, bestimmt wird, infolge der Speicherfähigkeit des Katalysators für diese zweite Sonde zwangsläufig niedrig ist und somit das Emissionsverhalten der Brennkraftmaschine, insbesondere bei großem Katalysatorvolumen, verschlechtert wird. This arrangement has the disadvantage that the Regelfre sequence, the recognition time is known by the gas analysis time, the probes, the change time in Gemischbildner and the gas flow rate, that is the flow velocity, it is determined due to the storage capacity of the catalyst for said second probe is inevitably low, and thus, the emission performance of the internal combustion engine, in particular with a large volume of catalyst, is deteriorated.

Aufgabe der Erfindung ist es, eine Vorrichtung der gat tungsgemäßen Art so auszubilden, daß bei Vermeidung einer Querempfindlichkeit gegenüber Wasserstoff und unter Berücksichtigung der Speicherfähigkeit des Katalysators eine hohe Regelfrequenz der Vorrichtung gewährleistet ist. The object of the invention is to design a device of the gat tung-mentioned type that in avoiding cross-sensitivity to hydrogen and taking into account the storage capacity of the catalyst, a high control frequency of the device is ensured.

Die Aufgabe wird erfindungsgemäß durch das im kennzeich nenden Teil des Patentanspruchs 1 angegebene Merkmal gelöst. The object is inventively achieved by the method defined in the characterizing portion of claim 1 nenden feature. Eine besondere Ausgestaltung der Erfindung geht aus dem Unteranspruch hervor. A particular embodiment of the invention will become apparent from the dependent claim.

Unter Beibehaltung der bekannten motornahen ersten Sauer stoffsonde stromauf des Katalysators ist eine zweite Sauerstoffsonde im Katalysator vorgesehen. While maintaining the close-known sour first fabric probe upstream of the catalyst, a second oxygen sensor is provided in the catalyst. Durch die Anordnung dieser zweiten Sauerstoffsonde im Katalysator kann einerseits der Zustand des Katalysators bei der Gemischbildung berücksichtigt und eine Wasserstoffquer empfindlichkeit ausgeschlossen werden; By the arrangement of this second oxygen sensor in the catalytic converter of the state of the catalyst on the one hand included in the mixture formation and a hydrogen cross-sensitivity to be excluded; andererseits erlaubt diese Anordnung dennoch eine hohe Regelfrequenz, da die Abgase nicht das gesamte Katalysatorvolumen durch strömen müssen, um zur zweiten Sonde zu gelangen und das nachgeschaltete Katalysatorvolumen für eine restlose Umsetzung der Schadstoffe sorgt. On the other hand, this arrangement allows a high control frequency but, as the exhaust gases do not have to flow through the entire volume of catalyst to move to the second probe and provides the downstream catalyst volume for a residue-free conversion of the pollutants.

Ein Ausführungsbeispiel der Erfindung sei nachstehend anhand der Zeichnung beschrieben. An embodiment of the invention will be described below with reference to the drawing. Es zeigt It shows

Fig. 1 schematisch eine erfindungsgemäße Vorrich tung bestehend aus Brennkraftmaschine, Katalysator und zwei Sauerstoffsonden, Fig. 1 shows schematically a Vorrich inventive processing consisting of the internal combustion engine, catalyst and two oxygen probes,

Fig. 2 schematisch eine besondere Ausführungsform des Katalysators. Fig. 2 shows schematically a particular embodiment of the catalyst.

Fig. 1 zeigt schematisch eine Brennkraftmaschine 1 , an die über ein Abgasleitungssystem 2 ein Katalysator 3 und im Anschluß an diesen ein Schalldämpfer 4 angeschlossen ist. Fig. 1 shows schematically an internal combustion engine 1 to which an exhaust pipe system 2, a catalyst 3, and following this, a muffler 4 is connected. Eine stromauf des Katalysators 3 angeordnete Sauer stoffsonde 5 mißt den Sauerstoffgehalt im Abgas vor dem Katalysator 3 und erlaubt durch ihre Anordnung eine hohe Regelfrequenz. An upstream of the catalyst 3 arranged Sauer fabric probe 5 measures the oxygen content in the exhaust gas upstream of the catalyst 3 and allowed by their arrangement, a high control frequency. Die im Katalysator 3 angeordnete zweite Sauerstoffsonde 6 berücksichtigt den Zustand des Katalysators 3 und weist, da freier Wasserstoff im Kataly sator 3 schon oxidiert wurde, eine geringe Wasserstoffquer empfindlichkeit auf. The catalyst 3 arranged in the second oxygen probe 6 takes into account the state of the catalyst 3 and has, as free hydrogen in Kataly sator 3 was already oxidized, a low hydrogen cross sensitivity. Die von den beiden Sauerstoffsonden 5 und 6 abgegebenen Signale werden einer Regeleinrichtung 7 zugeführt, die ein entsprechendes Signal an einen Gemisch bildner 8 eines Saugrohrsystems 9 weitergibt. The output from the two oxygen probes 5 and 6, signals are fed to a control device 7, the formers 8 further outputs a corresponding signal to a mixture of a manifold system. 9

Eine besonders günstige Ausgestaltung der erfindungsge mäßen Vorrichtung ist der Fig. 2 zu entnehmen. A particularly advantageous embodiment of the erfindungsge MAESSEN device is shown in FIG. 2. Der Katalysator 3 besteht hierbei aus zwei voneinander ge trennten Elementen, zB zwei Monolithblöcken 10 und 11 , und die zweite Sauerstoffsonde 6 ist in einem Zwischenraum 12 zwischen den beiden Monolithblöcken 10 , 11 angeordnet. The catalyst 3 here consists of two elements separated from each other ge, for example, two monolith blocks 10 and 11, and the second oxygen sensor 6 is disposed in a gap 12 between the two monolith blocks 10,. 11 Sie kann hierbei ungehindert vom Abgasstrom beaufschlagt werden. It can be applied here without hindrance from the exhaust stream. Bei einer Aufteilung des Gesamtvolumens des Katalysators 3 in zwei ungleich große Elemente kann die Sauerstoffsonde 6 stromab des kleineren ( 11 ) und stromauf des größeren ( 10 ) Elementes angeordnet sein, wodurch die bis zur Sonde 6 noch nicht vollständig umgesetzten Abgase im Monolithblock 10 vollständig nachbehandelt werden können. In a breakdown of the total volume of the catalyst 3 into two unequal sized elements the oxygen probe 6 may be downstream of the smaller, thereby to probe 6 is not completely converted exhaust gases fully treated (11) and arranged upstream of the larger (10) element in the monolith block 10 can be.

Claims (2)

1. Vorrichtung zum Verringern von Abgas-Schadstoff-Kompo nenten einer Brennkraftmaschine mit einem Katalysator im Abgasweg der Brennkraftmaschine, einer stromauf des Katalysators angeordneten ersten Sauerstoffsonde und einer zweiten Sauerstoffsonde, dadurch gekennzeichnet, daß die zweite Sauerstoffsonde ( 6 ) im Katalysator ( 3 ) angeordnet ist. 1. A device for reducing exhaust emission compo nents of an internal combustion engine having a catalyst in the exhaust path of the internal combustion engine, an upstream catalyst disposed first oxygen sensor and a second oxygen probe, characterized in that said second oxygen sensor (6) arranged in the catalyst (3) is.
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß der Katalysator ( 3 ) aus zwei voneinander getrennten Monolithblöcken ( 10 , 11 ) besteht und die zweite Sauer stoffsonde ( 6 ) in einem Zwischenraum ( 12 ) zwischen den beiden Monolithblöcken ( 10 , 11 ) angeordnet ist. 2. Device according to claim 1, characterized in that the catalyst (3) of two separate monolith blocks (10, 11) and the second Sauer fabric probe (6) in an intermediate space (12) between the two monolith blocks (10, 11) is arranged.
DE19883821345 1988-06-24 1988-06-24 Device for reducing exhaust pollutants from an internal combustion engine Withdrawn DE3821345A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19883821345 DE3821345A1 (en) 1988-06-24 1988-06-24 Device for reducing exhaust pollutants from an internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19883821345 DE3821345A1 (en) 1988-06-24 1988-06-24 Device for reducing exhaust pollutants from an internal combustion engine

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DE3821345A1 true DE3821345A1 (en) 1989-06-22

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19502011A1 (en) * 1994-02-15 1995-08-17 Ford Werke Ag Method and apparatus for limiting the internal temperature of a catalyst
DE19808382A1 (en) * 1998-02-27 1999-09-02 Volkswagen Ag Controlling a NOx absorber catalyst
DE19946044C1 (en) * 1999-09-25 2001-01-25 Daimler Chrysler Ag Exhaust gas purification apparatus used on Otto engines has lambda probe arranged between two three-way catalysts
WO2004063541A1 (en) * 2003-01-09 2004-07-29 Emitec Gesellschaft Für Emissionstechnologie Mbh Method for treating a fluid and honeycomb body
WO2019015845A1 (en) 2017-07-19 2019-01-24 Bayerische Motoren Werke Aktiengesellschaft Exhaust gas system for an internal combustion engine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2319606A1 (en) * 1973-04-18 1974-11-14 Volkswagenwerk Ag Catalyst for the catalytic purification of exhaust gases
GB1480393A (en) * 1973-06-29 1977-07-20 Bosch Gmbh Robert Method for reducing the amount of pollutants in engine exhaust gases
DE3224347A1 (en) * 1982-06-30 1983-08-04 Daimler Benz Ag Device for reducing pollutant components in the exhaust gas of an internal combustion engine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2319606A1 (en) * 1973-04-18 1974-11-14 Volkswagenwerk Ag Catalyst for the catalytic purification of exhaust gases
GB1480393A (en) * 1973-06-29 1977-07-20 Bosch Gmbh Robert Method for reducing the amount of pollutants in engine exhaust gases
DE3224347A1 (en) * 1982-06-30 1983-08-04 Daimler Benz Ag Device for reducing pollutant components in the exhaust gas of an internal combustion engine

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19502011A1 (en) * 1994-02-15 1995-08-17 Ford Werke Ag Method and apparatus for limiting the internal temperature of a catalyst
DE19502011C2 (en) * 1994-02-15 1998-07-16 Ford Werke Ag A method for limiting the internal temperature of a catalyst
DE19808382A1 (en) * 1998-02-27 1999-09-02 Volkswagen Ag Controlling a NOx absorber catalyst
US6408615B1 (en) 1998-02-27 2002-06-25 Volkswagen Ag Method for controlling an NOx accumulating catalytic converter
DE19946044C1 (en) * 1999-09-25 2001-01-25 Daimler Chrysler Ag Exhaust gas purification apparatus used on Otto engines has lambda probe arranged between two three-way catalysts
WO2004063541A1 (en) * 2003-01-09 2004-07-29 Emitec Gesellschaft Für Emissionstechnologie Mbh Method for treating a fluid and honeycomb body
US7448201B2 (en) 2003-01-09 2008-11-11 Emitec Gesellschaft Fuer Emissionstechnologie Mbh Honeycomb body and method for treating a fluid
WO2019015845A1 (en) 2017-07-19 2019-01-24 Bayerische Motoren Werke Aktiengesellschaft Exhaust gas system for an internal combustion engine
DE102017212307A1 (en) 2017-07-19 2019-01-24 Bayerische Motoren Werke Aktiengesellschaft Exhaust system for an internal combustion engine

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