CH676278A5 - - Google Patents
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- Publication number
- CH676278A5 CH676278A5 CH256088A CH256088A CH676278A5 CH 676278 A5 CH676278 A5 CH 676278A5 CH 256088 A CH256088 A CH 256088A CH 256088 A CH256088 A CH 256088A CH 676278 A5 CH676278 A5 CH 676278A5
- Authority
- CH
- Switzerland
- Prior art keywords
- chamber
- catalytic converter
- exhaust manifold
- baffle
- exhaust
- Prior art date
Links
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
- 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
- F01N3/28—Construction of catalytic reactors
-
- 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
- F01N3/28—Construction of catalytic reactors
- F01N3/2882—Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices
- F01N3/2885—Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices with exhaust silencers in a single housing
-
- 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
- F01N2230/00—Combination of silencers and other devices
- F01N2230/04—Catalytic converters
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Exhaust Gas After Treatment (AREA)
- Exhaust Silencers (AREA)
Abstract
The exhaust manifold (2) is connected to a generally cylindrical chamber (3). The chamber (3) is separated from the adjoining silencer (6) by a baffle (5). In order to achieve a good behaviour of the catalytic converter during cold starting and a good degree of conversion without power losses or increase in the fuel consumption of the engine, the catalytic converter (8) is arranged inside the chamber (3). The catalytic converter projects, preferably coaxially, from the end of a discharge pipe (7), directed from the baffle (5) towards the exhaust manifold (2), in such a way that it has the same distance on all sides from the wall of the chamber (3). <IMAGE>
Description
Die Erfindung betrifft eine Auspuffanlage nach dem Oberbegriff des Anspruchs 1.
Bei einer allgemein bekannten Auspuffanlage dieser Art ist der Katalysator unmittelbar in dem auf den Zylinder folgenden Auspuffkrümmer angeordnet. Dadurch ergibt sich zwar ein gutes Verhalten des Katalysators bei Kaltstart, weil sich der Katalysator in unmittelbarer Nähe des Zylinders befindet und demnach rasch erhitzt wird, doch beeinträchtigt der den gesamten Rohrquerschnitt ausfüllende Katalysator die Funktionsweise der Auspuffanlage; dies hat eine Verschlechterung der Leistung und eine Verringerung des abgegebenen Drehmoments sowie eine Verschlechterung des Kraftstoffverbrauches zur Folge. Der erhitzte Katalysator verursacht ferner unerwünschte Rückwirkungen auf den Zylinder.
Es ist auch schon bekannt, in der die erweiterte Kammer vom Schalldämpfer trennenden Prallwand ein mittleres Austrittsrohr vorzusehen, welches durch die Prallwand hindurch etwas in die davorliegende Kammer hinein eintritt, doch handelt es sich in diesen Fällen um Auspuffanlagen ohne Katalysator zur Entgiftung der Auspuffgase.
Es ist Aufgabe der Erfindung, die eingangs beschriebenen Auspuffanlagen derart zu verbessern, dass sich ein gutes Verhalten des Katalysators bei Kaltstart und ein guter Umsetzungsgrad der verunreinigenden Gase ergeben, ohne eine Leistungseinbusse bzw. eine Steigerung des Kraftstoffverbrauches in Kauf nehmen zu müssen.
Die Erfindung löst die gestellte Aufgabe durch die kennzeichnenden Merkmale des Anspruchs 1.
Obwohl der Katalysator nicht im Auspuffkrümmer, sondern in der Kammer angeordnet ist, wird bei Kaltstart eine vergleichsweise kurze Ansprechzeit des Katalysators erreicht, da der Katalysator mit Abgasen beaufschlagt wird, die noch nicht ausreichend expandieren konnten und daher eine hohe Temperatur aufweisen. Die Temperatur des Katalysators steigt beim Kaltstart somit rasch an, was auch noch durch die Halterung des Katalysators im Austrittsrohr, die einen sehr geringen Wärmeleitkoeffizient besitzt, begünstigt wird. Diese Anordnung hat auch den Vorteil, dass sie die Saugwirkung der im allgemeinen zylindrischen Kammer nicht beeinträchtigt, da am freien Ende des Katalysators aus Gründen der Kontinuität höhere Strömungsgeschwindigkeiten herrschen als in der freien Querschnittsfläche der Kammer.
Dadurch werden im Vergleich zu einer Auspuffanlage ohne Katalysator weder die Leistung noch der Kraftstoffverbrauch des Motors negativ beeinflusst.
Durch die frei auskragende Halterung des Katalysators ergibt sich ein guter Umsetzungsgrad, weil die Stirnfläche des freien Endes des Katalysators und auch ein Grossteil der Katalysatoraussenfläche der Abgasströmung ausgesetzt werden, ohne dass dieselbe beeinträchtigt wird und ohne somit die Wirksamkeit der Auspuffanlage zu verschlechtern.
In weiterer Ausbildung der Erfindung verjüngt sich der Katalysator zum Auspuffkrümmer hin in Form eines Rotationskörpers oder pyramidenförmig. Diese Verjüngung des Katalysators an seinem vorderen Ende verringert die Wärmeabstrahlungsfläche in diesem Bereich, so dass sich bei Kaltstart eine noch raschere Erwärmung ergibt, die zu einem weiter verbesserten Verhalten und zu einem höheren Umsetzungsgrad bei verringerter Motorbelastung führt. Ausserdem wird dadurch eine Anpassung des freien Katalysatorendes an die Form eines sich erweiternden Teils der Kammer und einer etwaigen Kammer mit kegelstumpfförmigem Querschnitt zwischen dieser Kammer und dem Auspuffkrümmer erreicht, so dass der Katalysator weiter zum Eingang der Kammer hin und somit zum Zylinder hin vorversetzt werden kann.
Die Zeichnung zeigt ein Ausführungsbeispiel einer erfindungsgemässen Auspuffanlage für einen Zweitaktmotor in vereinfachter Darstellung im Teilschnitt.
Vom Auslassschlitz des Zylinders 1 eines für ein Zweirad-Fahrzeug bestimmten Zweitaktmotors tritt ein Auspuffkrümmer 2 aus, an den eine Kammer angeschlossen ist, die einen zylindrischen Teil 3 und einen kegelstumpfförmigen Teil 4 aufweist. Der Teil 3 ist durch eine Prallwand 5 von einem Schalldämpfer 6 getrennt. Von der Prallwand 5 ist ein Austrittsrohr 7 zum Auspuffkrümmer 2 hin gerichtet und in sein freies Ende ist ein Katalysator 8 eingesetzt, der frei auskragend gleichachsig und von allen Seiten der Wand der Kammer 3, 4 gleich weit entfernt gehalten ist. Der Katalysator 8 kann sich zum Auspuffkrümmer 2 hin in Form eines Rotationskörpers verjüngen, wie dies strichpunktiert angedeutet ist.
Erfindungswesentlich ist, dass der Katalysator 8 stirnseitig angeströmt und axial durchströmt wird, weil auf diese Weise die Expansion der Auspuffgase keinerlei Beeinträchtigung erfährt.
The invention relates to an exhaust system according to the preamble of claim 1.
In a generally known exhaust system of this type, the catalytic converter is arranged directly in the exhaust manifold following the cylinder. Although this results in a good behavior of the catalytic converter on cold start because the catalytic converter is located in the immediate vicinity of the cylinder and is therefore heated quickly, the catalytic converter filling the entire pipe cross-section impairs the functioning of the exhaust system; this results in a deterioration in performance and a decrease in the torque output as well as a deterioration in fuel consumption. The heated catalyst also causes undesirable reactions on the cylinder.
It is also known to provide a central outlet pipe in the baffle separating the expanded chamber from the muffler, which enters somewhat into the chamber in front through the baffle, but in these cases exhaust systems without a catalyst are used to detoxify the exhaust gases.
It is an object of the invention to improve the exhaust systems described at the outset in such a way that the catalytic converter behaves well on a cold start and the degree of conversion of the contaminating gases is good, without having to accept a loss in performance or an increase in fuel consumption.
The invention solves this problem by the characterizing features of claim 1.
Although the catalytic converter is not arranged in the exhaust manifold, but in the chamber, a comparatively short response time of the catalytic converter is achieved on cold start, since the catalytic converter is exposed to exhaust gases which have not yet been able to expand sufficiently and are therefore at a high temperature. The temperature of the catalytic converter rises rapidly during a cold start, which is also favored by the fact that the catalytic converter is held in the outlet pipe, which has a very low coefficient of thermal conductivity. This arrangement also has the advantage that it does not adversely affect the suction effect of the generally cylindrical chamber, since for reasons of continuity there are higher flow rates at the free end of the catalyst than in the free cross-sectional area of the chamber.
In comparison to an exhaust system without catalytic converter, this does not have a negative impact on the performance or fuel consumption of the engine.
The freely projecting mounting of the catalytic converter results in a good degree of implementation because the end face of the free end of the catalytic converter and also a large part of the catalytic converter outer area are exposed to the exhaust gas flow without being adversely affected and thus without impairing the effectiveness of the exhaust system.
In a further embodiment of the invention, the catalytic converter tapers towards the exhaust manifold in the form of a rotating body or pyramid-shaped. This tapering of the catalytic converter at its front end reduces the heat radiation area in this area, so that during cold start there is an even faster heating, which leads to a further improved behavior and a higher degree of conversion with a reduced engine load. In addition, this adapts the free catalyst end to the shape of an expanding part of the chamber and any chamber with a frustoconical cross section between this chamber and the exhaust manifold, so that the catalyst can be advanced further towards the entrance of the chamber and thus towards the cylinder .
The drawing shows an embodiment of an exhaust system according to the invention for a two-stroke engine in a simplified representation in partial section.
An exhaust manifold 2 emerges from the outlet slot of the cylinder 1 of a two-stroke engine intended for a two-wheeled vehicle, to which a chamber is connected, which has a cylindrical part 3 and a frustoconical part 4. Part 3 is separated by a baffle 5 from a silencer 6. From the baffle 5, an outlet pipe 7 is directed toward the exhaust manifold 2 and in its free end a catalyst 8 is inserted, which is cantilevered and coaxial and is kept the same distance from all sides of the chamber 3, 4. The catalytic converter 8 can taper towards the exhaust manifold 2 in the form of a rotating body, as is indicated by dash-dotted lines.
It is essential to the invention that the face of the catalytic converter 8 is flowed through and axially flowed through, because in this way the expansion of the exhaust gases is not impaired in any way.
Claims (3)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE8808796U DE8808796U1 (en) | 1988-07-08 | 1988-07-08 | Combustion product exhaust system with catalyst for two-stroke engines |
Publications (1)
Publication Number | Publication Date |
---|---|
CH676278A5 true CH676278A5 (en) | 1990-12-28 |
Family
ID=6825799
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CH256088A CH676278A5 (en) | 1988-07-08 | 1988-07-05 |
Country Status (6)
Country | Link |
---|---|
BE (1) | BE1002078A6 (en) |
CH (1) | CH676278A5 (en) |
DE (1) | DE8808796U1 (en) |
FR (1) | FR2633664B3 (en) |
GB (1) | GB2220150A (en) |
NL (1) | NL8801672A (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ATA133189A (en) * | 1989-06-01 | 1994-09-15 | Laimboeck Franz | EXHAUST SYSTEM FOR TWO-STROKE COMBUSTION ENGINES |
AT396170B (en) * | 1989-06-01 | 1993-06-25 | Laimboeck Franz | EXHAUST SYSTEM FOR TWO-STROKE COMBUSTION ENGINES |
DE9011403U1 (en) * | 1990-08-04 | 1990-11-08 | PROTERRA Umwelttechnik oHG Hilgers & Hilgers, 5227 Windeck | Catalyst for installation in exhaust systems of two-wheeled vehicles with combustion engines |
US5635141A (en) * | 1992-03-17 | 1997-06-03 | E. I. Du Pont De Nemours And Company | Radial flow exhaust catalytic converter |
FR2775497B1 (en) * | 1998-02-27 | 2000-05-05 | Inst Francais Du Petrole | NEW CATALYTIC ELEMENT FOR THE TREATMENT OF EXHAUST GASES FROM AN INTERNAL COMBUSTION ENGINE |
US7384609B2 (en) | 2003-01-29 | 2008-06-10 | Brp-Rotax Gmbh & Co. Kg | Pre-converter device for cleaning exhaust gas for an internal combustion engine |
DE112005001774A5 (en) * | 2004-08-09 | 2008-06-26 | Avl List Gmbh | Internal combustion engine |
AT501402B1 (en) * | 2004-08-19 | 2007-07-15 | Avl List Gmbh | Internal combustion engine for hand tool or vehicle has exhaust pipe partially surrounding exhaust gas treatment catalytic converter |
IT201700061755A1 (en) * | 2017-06-06 | 2018-12-06 | Vins S R L | THERMAL COMBUSTION INTERNAL THERMAL MOTOR WITH DRAINAGE CATALYST |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB794915A (en) * | 1954-05-06 | 1958-05-14 | Kellogg M W Co | Method and apparatus for catalytic processes |
NL111862C (en) * | 1959-07-31 | |||
GB920679A (en) * | 1961-07-28 | 1963-03-13 | Oxy Catalyst Inc | Improvements in or relating to catalytic exhaust purifiers for engines operating on gasoline |
JPS53110617U (en) * | 1977-02-09 | 1978-09-04 | ||
SE8004632L (en) * | 1979-06-29 | 1980-12-30 | Johnson Matthey Co Ltd | COMBUSTION ENGINE WITH EXHAUST CLEANER AND EXHAUST CLEANING PROCEDURE |
GB2122914B (en) * | 1979-06-29 | 1984-06-13 | Johnson Matthey Plc | Process for oxidising particles in diesel exhaust |
SE8102023L (en) * | 1980-03-31 | 1981-10-01 | Johnson Matthey Co Ltd | TURBO OVERLOAD COMBUSTION ENGINE |
EP0070619A3 (en) * | 1981-07-16 | 1984-01-04 | Johnson Matthey, Inc., | Regenerating diesel emissions control devices |
-
1988
- 1988-07-01 BE BE8800762A patent/BE1002078A6/en not_active IP Right Cessation
- 1988-07-01 FR FR8808967A patent/FR2633664B3/en not_active Expired - Lifetime
- 1988-07-01 GB GB8815657A patent/GB2220150A/en not_active Withdrawn
- 1988-07-01 NL NL8801672A patent/NL8801672A/en not_active Application Discontinuation
- 1988-07-05 CH CH256088A patent/CH676278A5/de not_active IP Right Cessation
- 1988-07-08 DE DE8808796U patent/DE8808796U1/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
NL8801672A (en) | 1990-02-01 |
DE8808796U1 (en) | 1988-09-29 |
GB2220150A (en) | 1990-01-04 |
FR2633664A3 (en) | 1990-01-05 |
GB8815657D0 (en) | 1988-08-10 |
BE1002078A6 (en) | 1990-06-19 |
FR2633664B3 (en) | 1990-06-08 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PFA | Name/firm changed |
Owner name: PIAGGIO VEICOLI EUROPEI S.P.A. |
|
PUE | Assignment |
Owner name: PIAGGIO VEICOLI EUROPEI S.R.L. |
|
PL | Patent ceased |