EP0592258A1 - Exhaust device for internal combustion engines - Google Patents

Exhaust device for internal combustion engines Download PDF

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Publication number
EP0592258A1
EP0592258A1 EP93402138A EP93402138A EP0592258A1 EP 0592258 A1 EP0592258 A1 EP 0592258A1 EP 93402138 A EP93402138 A EP 93402138A EP 93402138 A EP93402138 A EP 93402138A EP 0592258 A1 EP0592258 A1 EP 0592258A1
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EP
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Prior art keywords
monolith
treatment
internal combustion
exhaust device
exhaust
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EP93402138A
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German (de)
French (fr)
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EP0592258B1 (en
Inventor
Said Zidat
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Renault SAS
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Renault SAS
Regie Nationale des Usines Renault
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    • 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
    • F01N3/2892—Exhaust flow directors or the like, e.g. upstream of catalytic device
    • 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
    • F01N13/00—Exhaust 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
    • F01N13/009—Exhaust 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
    • F01N13/0097—Exhaust 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 the purifying devices are arranged in a single housing

Definitions

  • the present invention relates to an exhaust device for purifying the exhaust gases of an internal combustion engine fitted in particular to a motor vehicle.
  • the invention relates more particularly to a device for purifying exhaust gases by catalytic conversion.
  • a catalytic converter is formed by an envelope delimiting a closed volume inserted in the exhaust line.
  • This envelope has, in the direction of flow of the exhaust gases, an inlet end of divergent frustoconical shape, a cylindrical or oval body, where is positioned a gas treatment structure formed by a metallic or ceramic reactor, again called monolith, comprising a plurality of axial channels arranged in honeycomb and coated with catalytic substances, and an outlet end of frustoconical shape.
  • the object of the present invention is therefore to propose a simple and economical system which overcomes the drawbacks of the prior art by ensuring excellent distribution of the exhaust gases over the entire section. transverse monoliths used for catalytic purification of exhaust gases.
  • the exhaust device for an internal combustion engine comprises a casing intended to be connected to the engine exhaust line and having a cylindrical body, tapered inlet and outlet ends respectively divergent and convergent, said envelope containing at least one monolith for the treatment of gases comprising multiple axially arranged channels coated with catalytic substances,
  • the exhaust device is characterized in that diffusing means are arranged upstream of the treatment monolith in the direction of gas flow to ensure the distribution of exhaust gases over the entire cross section of the monolith, the diffusing means being constituted by a monolith of reduced axial dimension with respect to the axial dimension of the treatment monolith and by an adjacent free cavity extending between the latter and the treatment monolith.
  • the axial length of the diffuser monolith is less than 1/4 of the total axial length of the monoliths present in said envelope.
  • the treatment monolith and the diffusing means are arranged inside the cylindrical body.
  • two treatment monoliths are arranged downstream of the diffusing means.
  • the axial dimension of the monolith is between 10 and 50 mm.
  • the diffuser monolith is coated with catalytic substances and participates in the treatment of gases.
  • Figure 1 is a schematic view in longitudinal section of a catalytic converter according to the invention.
  • the exhaust device 1 comprising means for catalytically purifying the exhaust gases of an internal combustion engine shown in FIG. 1 comprises an envelope conventionally defining a cylindrical body with circular (or oval) section 2 surrounded by tapered inlet 3 and outlet 4 ends respectively divergent and convergent.
  • the inlet duct 5 is an integral part of the frustoconical end 3 and the outlet duct 6 is an integral part of the frustoconical end 4.
  • the ducts 5 and 6 allow the device 1 to be connected to the exhaust line of an internal combustion engine.
  • honeycomb body Inside the body 2 are housed one behind the other three monoliths 7, 8 and 9.
  • monoliths 7, 8 and 9 also known under the name honeycomb body consist of cylindrical blocks, for example of porous ceramic, having a multitude of axially extending flow channels, of square or trapezoidal section, in which the exhaust gases flow.
  • the monolith 7 ⁇ 15Hdisposed at the inlet of the body 2, in the direction of the gas flow, has a limited axial length compared to the monoliths 8 and 9. This length can vary between 10 and 50 mm for a diameter of 100 mm .
  • the monolith 8 is arranged behind the monolith 7 at a distance of between 10 and 50 mm so as to leave a free cavity 10 between them.
  • the monolith 8 extends, for its part, over a length of between 50 and 200 mm.
  • the monolith 9 is placed after the monolith 8 with the interposition of a free cavity 11.
  • the dimensions of the monolith 9 are substantially the same as those of the monolith 8.
  • the axial length of the monolith 7 is preferably chosen, less than 1/4 the total axial length of the different monoliths present inside the body 2.
  • Monoliths 8 and 9 are coated with catalytic active substances which may be of a similar nature, with oxidation or reduction or bifunctional, or even with catalytic substances of different natures, the the first can be for example oxidation and the second reduction.
  • the diffuser monolith 7, for its part, may be coated with a catalyst, with oxidation or reduction or bifunctional, or else may not be.
  • the thin monolith 7 and the adjacent free cavity 10 form diffusing means which make it possible to considerably improve the distribution of the exhaust gases over the entire cross section of the cylindrical body 2 and therefore of the monolith 8, distribution initiated by the divergent tapered inlet end 3.
  • This distribution of the exhaust gases has the effect of causing the latter to penetrate all or almost all of the gas flow channels formed in the monolith 8.
  • the treatment monoliths 8 and 9 are used optimally.
  • the increase in the useful surface of these monoliths makes it possible to improve the treatment of the exhaust gases and to reduce their dimensions with equivalent treatment or even to increase the lifetime of the catalytic converter with equivalent dimensions.
  • the dimensions of the monolith 7 and of the cavity 10 are adjusted to each exhaust line by series of measurements on the test benches so that by operating the gas flow rates flowing through the exhaust device, they have the best possible diffusion.
  • the exhaust device according to the invention relates to both ceramic monoliths and metal monoliths.
  • the exhaust device according to the invention may comprise only a diffuser monolith 7 and a treatment monolith, the latter then playing the role of the two treatment monoliths 8 and 9 previously described.

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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

Exhaust device for an internal combustion engine in order to purify the exhaust gases, including a casing intended to be connected to the exhaust line of the engine and exhibiting a cylindrical body (2), inlet (3) and outlet (4) frustoconical ends which are respectively divergent and convergent, the said casing containing at least one monolith (solid-state element) for the treatment of the gases (8, 9) including multiple ducts located longitudinally and coated with catalytic substances, characterised in that the diffuser means (7, 10) are located upstream of the treatment monolith (8, 9) in the direction of flow of the gases in order to ensure the distribution of the exhaust gases over the entire transverse section of the monolith (8, 9), the said diffusing means being made up of a monolith (7) of axial dimension reduced with respect to the axial dimension of the treatment monolith (8, 9) and by an adjacent free cavity (10) extending between the latter and the said monolith (8, 9). <IMAGE>

Description

La présente invention se rapporte à un dispositif d'échappement pour épurer les gaz d'échappement d'un moteur à combustion interne équipant notamment un véhicule automobile. L'invention concerne plus particulièrement un dispositif pour purifier les gaz d'échappement par conversion catalytique.The present invention relates to an exhaust device for purifying the exhaust gases of an internal combustion engine fitted in particular to a motor vehicle. The invention relates more particularly to a device for purifying exhaust gases by catalytic conversion.

D'une façon générale les normes concernant la pollution des moteurs à combustion interne équipant les véhicules automobiles se sévérisent chaque jour davantage dans l'ensemble des pays industrialisés. L'industrie automobile est donc aujourd'hui toute entière mobilisée à trouver des solutions techniques pour répondre à ces contraintes et ce sans trop pénaliser ni les performances des moteurs ni leur prix de revient.In general, the standards concerning the pollution of internal combustion engines fitted to motor vehicles are becoming more and more severe every day in all industrialized countries. The automotive industry is therefore today fully mobilized to find technical solutions to meet these constraints without penalizing either the performance of the engines or their cost price.

Pour lutter contre l'émission des gaz polluants, l'industrie automobile a adopté l'utilisation de dispositifs d'échappement traitant par conversion catalytique les composants nocifs des gaz d'échappement. Ces dispositifs encore appelés pots catalytiques permettent en effet l'oxydation des hydrocarbures imbrûlés HC et du monoxyde de carbone CO et la réduction des oxydes d'azote NOx. Ces réactions sont fortement accélérées par la présence d'un catalyseur de sorte qu'elles peuvent s'accomplir pendant le bref temps de passage des gaz d'échappement à travers le pot.To fight against the emission of polluting gases, the automobile industry has adopted the use of exhaust devices treating by catalytic conversion the harmful components of the exhaust gases. These devices, also called catalytic converters, in fact allow the oxidation of unburnt hydrocarbons HC and carbon monoxide CO and the reduction of nitrogen oxides NOx. These reactions are greatly accelerated by the presence of a catalyst so that they can be accomplished during the short time that the exhaust gases pass through the pot.

Classiquement un pot catalytique est formé par une enveloppe délimitant un volume clos insérée dans la ligne d'échappement. Cette enveloppe présente, dans le sens d'écoulement des gaz d'échappement, une extrémité d'entrée de forme tronconique divergente, un corps cylindrique ou ovale, où est positionné une structure de traitement des gaz formée par un réacteur métallique ou céramique, encore appelé monolithe, comportant une pluralité de canaux axiaux disposés en nid d'abeille et revêtus de substances catalytiques, et une extrémité de sortie de forme tronconique divergente.Conventionally, a catalytic converter is formed by an envelope delimiting a closed volume inserted in the exhaust line. This envelope has, in the direction of flow of the exhaust gases, an inlet end of divergent frustoconical shape, a cylindrical or oval body, where is positioned a gas treatment structure formed by a metallic or ceramic reactor, again called monolith, comprising a plurality of axial channels arranged in honeycomb and coated with catalytic substances, and an outlet end of frustoconical shape.

Il est apparu à la demanderesse que la seule présence d'un simple divergent disposé à l'entrée du monolithe ne permet pas de réaliser une distribution de l'écoulement des gaz d'échappement sur toute la surface transversale d'entrée du monolithe. Il en résulte que seule une partie des canaux est réellement alimentée par l'écoulement des gaz d'échappement du moteur. Cela conduit, pour compenser cette perte en section, à surdimensionner le monolithe en l'allongeant pour pouvoir traiter convenablement la totalité des gaz d'échappement.It has appeared to the applicant that the mere presence of a simple divergent disposed at the inlet of the monolith does not make it possible to distribute the flow of the exhaust gases over the entire transverse entry surface of the monolith. As a result, only a part of the channels is actually supplied by the flow of engine exhaust gases. This leads, to compensate for this loss in section, to oversize the monolith by lengthening it in order to be able to treat all of the exhaust gases properly.

L'objet de la présente invention est donc de proposer un système simple et économique qui permet de pallier aux inconvénients de l'art antérieur en assurant une excellente distribution des gaz d'échappement sur toute la section transversale des monolithes servant à l'épuration catalytique des gaz d'échappement.The object of the present invention is therefore to propose a simple and economical system which overcomes the drawbacks of the prior art by ensuring excellent distribution of the exhaust gases over the entire section. transverse monoliths used for catalytic purification of exhaust gases.

Le dispositif d'échappement pour moteur à combustion interne selon l'invention comporte une enveloppe destinée à être raccordée à la ligne d'échappement du moteur et présentant un corps cylindrique, des extrémités d'entrée et de sortie tronconiques respectivement divergente et convergente, ladite enveloppe contenant au moins un monolithe pour le traitement des gaz comportant de multiples canaux disposés axialement et revêtus de substances catalytiques,The exhaust device for an internal combustion engine according to the invention comprises a casing intended to be connected to the engine exhaust line and having a cylindrical body, tapered inlet and outlet ends respectively divergent and convergent, said envelope containing at least one monolith for the treatment of gases comprising multiple axially arranged channels coated with catalytic substances,

Selon l'invention le dispositif d'échappement est caractérisé en ce que des moyens diffuseurs sont disposés en amont du monolithe de traitement dans le sens de l'écoulement des gaz pour assurer la distribution des gaz d'échappement sur la totalité de la section transversale du monolithe les moyens diffuseurs étant constitués par un monolithe de dimension axiale réduite par rapport à la dimension axiale du monolithe de traitement et par une cavité libre adjacente s'étendant entre ce dernier et le monolithe de traitement .According to the invention the exhaust device is characterized in that diffusing means are arranged upstream of the treatment monolith in the direction of gas flow to ensure the distribution of exhaust gases over the entire cross section of the monolith, the diffusing means being constituted by a monolith of reduced axial dimension with respect to the axial dimension of the treatment monolith and by an adjacent free cavity extending between the latter and the treatment monolith.

Selon une autre caractéristique du dispositif d'échappement selon l'invention, la longueur axiale du monolithe diffuseur est inférieure au 1/4 de la longueur axiale totale des monolithes présents dans ladite enveloppe.According to another characteristic of the exhaust device according to the invention, the axial length of the diffuser monolith is less than 1/4 of the total axial length of the monoliths present in said envelope.

Selon une autre caractéristique du dispositif d'échappement selon l'invention, le monolithe de traitement et les moyens diffuseurs sont disposés à l'intérieur du corps cylindrique.According to another characteristic of the exhaust device according to the invention, the treatment monolith and the diffusing means are arranged inside the cylindrical body.

Selon une autre caractéristique du dispositif d'échappement selon l'invention, deux monolithes de traitement sont disposés en aval des moyens diffuseurs.According to another characteristic of the exhaust device according to the invention, two treatment monoliths are arranged downstream of the diffusing means.

Selon une autre caractéristique du dispositif d'échappement selon l'invention, la dimension axiale du monolithe est comprise entre 10 et 50 mm.According to another characteristic of the exhaust device according to the invention, the axial dimension of the monolith is between 10 and 50 mm.

Selon une autre caractéristique du dispositif d'échappement selon l'invention, le monolithe diffuseur est revêtu de substances catalytiques et participe au traitement des gaz.According to another characteristic of the exhaust device according to the invention, the diffuser monolith is coated with catalytic substances and participates in the treatment of gases.

On comprendra mieux les buts, aspects et avantages de la présente invention, d'après la description donnée ci-après d'un mode de réalisation de l'invention, donné à titre d'exemple non limitatif, en se référant au dessin annexé, dans lequel :
   la figure 1 est une vue schématique en coupe longitudinale d'un pot catalytique selon l'invention.The aims, aspects and advantages of the present invention will be better understood from the description given below of an embodiment of the invention, given by way of nonlimiting example, with reference to the appended drawing, in which :
Figure 1 is a schematic view in longitudinal section of a catalytic converter according to the invention.

Le dispositif d'échappement 1 comportant des moyens d'épuration catalytique des gaz d'échappement d'un moteur à combustion interne représenté à la figure 1 comporte une enveloppe définissant classiquement un corps cylindrique à section circulaire (ou ovale) 2 entouré par des extrémités tronconiques d'entrée 3 et de sortie 4 respectivement divergente et convergente. Le conduit d'admission 5 fait partie intégrante de l'extrémité tronconique 3 et le conduit de sortie 6 fait partie intégrante de l'extrémité tronconique 4. Les conduits 5 et 6 permettent le raccordement du dispositif 1 à la ligne d'échappement d'un moteur à combustion interne.The exhaust device 1 comprising means for catalytically purifying the exhaust gases of an internal combustion engine shown in FIG. 1 comprises an envelope conventionally defining a cylindrical body with circular (or oval) section 2 surrounded by tapered inlet 3 and outlet 4 ends respectively divergent and convergent. The inlet duct 5 is an integral part of the frustoconical end 3 and the outlet duct 6 is an integral part of the frustoconical end 4. The ducts 5 and 6 allow the device 1 to be connected to the exhaust line of an internal combustion engine.

A l'intérieur du corps 2 sont logés l'un derrière l'autre trois monolithes 7, 8 et 9. Ces monolithes également connus sous l'appellation corps à nid d'abeilles se composent de blocs cylindriques, par exemple en céramique poreuse, présentant une multitude de canaux d'écoulement s'étendant axialement, de section carrée ou trapézoïdale, dans lesquels s'écoulent les gaz d'échappement.Inside the body 2 are housed one behind the other three monoliths 7, 8 and 9. These monoliths also known under the name honeycomb body consist of cylindrical blocks, for example of porous ceramic, having a multitude of axially extending flow channels, of square or trapezoidal section, in which the exhaust gases flow.

Le monolithe 7 ÿ15Hdisposé à l'entrée du corps 2, dans le sens de l'écoulement des gaz, présente une longueur axiale restreinte par rapport aux monolithes 8 et 9. Cette longueur peut varier entre 10 et 50 mm pour un diamètre de 100 mm. Le monolithe 8 est disposé derrière le monolithe 7 à une distance comprise entre 10 et 50 mm de façon à laisser une cavité libre 10 entre eux. Le monolithe 8 s'étend quant à lui, sur une longueur comprise entre 50 et 200 mm. Le monolithe 9 est disposé à la suite du monolithe 8 avec interposition d'une cavité libre 11. Les dimensions du monolithe 9 sont sensiblement les mêmes que celles du monolithe 8.The monolith 7 ÿ15Hdisposed at the inlet of the body 2, in the direction of the gas flow, has a limited axial length compared to the monoliths 8 and 9. This length can vary between 10 and 50 mm for a diameter of 100 mm . The monolith 8 is arranged behind the monolith 7 at a distance of between 10 and 50 mm so as to leave a free cavity 10 between them. The monolith 8 extends, for its part, over a length of between 50 and 200 mm. The monolith 9 is placed after the monolith 8 with the interposition of a free cavity 11. The dimensions of the monolith 9 are substantially the same as those of the monolith 8.

La longueur axiale du monolithe 7 est choisie de façon préférentielle, inférieure au 1/4 de la longueur totale axiale des différents monolithes présents à l'intérieur du corps 2.The axial length of the monolith 7 is preferably chosen, less than 1/4 the total axial length of the different monoliths present inside the body 2.

Les monolithes 8 et 9, plus particulièrement destinés au traitement des gaz d'échappement, sont revêtus de substances actives catalytiques qui peuvent être de nature similaire, à oxydation ou à réduction ou bifonctionnel, ou bien encore par des substances catalytiques de natures différentes, le premier pouvant être par exemple à oxydation et le second à réduction. Le monolithe diffuseur 7, quant à lui peut être revêtu de catalyseur, à oxydation ou à réduction ou bifonctionnel, ou bien ne pas l'être.Monoliths 8 and 9, more particularly intended for the treatment of exhaust gases, are coated with catalytic active substances which may be of a similar nature, with oxidation or reduction or bifunctional, or even with catalytic substances of different natures, the the first can be for example oxidation and the second reduction. The diffuser monolith 7, for its part, may be coated with a catalyst, with oxidation or reduction or bifunctional, or else may not be.

Le monolithe 7 de faible épaisseur et la cavité libre adjacente 10 forment des moyens diffuseurs qui permettent d'améliorer considérablement la distribution des gaz d'échappement sur la totalité de la section transversale du corps cylindrique 2 et donc du monolithe 8, distribution amorcée par l'extrémité tronconique divergente d'entrée 3.The thin monolith 7 and the adjacent free cavity 10 form diffusing means which make it possible to considerably improve the distribution of the exhaust gases over the entire cross section of the cylindrical body 2 and therefore of the monolith 8, distribution initiated by the divergent tapered inlet end 3.

Cette distribution des gaz d'échappement a pour effet de faire pénétrer ces derniers la totalité ou la quasi-totalité des canaux d'écoulement des gaz formés dans le monolithe 8. Ainsi les monolithes de traitement 8 et 9 sont utilisés de façon optimale. L'augmentation de la surface utile de ces monolithes permet d'améliorer le traitement des gaz d'échappement et de réduire leurs dimensions à traitement équivalent ou encore d'augmenter la durée de vie du pot catalytique à dimensions équivalentes.This distribution of the exhaust gases has the effect of causing the latter to penetrate all or almost all of the gas flow channels formed in the monolith 8. Thus the treatment monoliths 8 and 9 are used optimally. The increase in the useful surface of these monoliths makes it possible to improve the treatment of the exhaust gases and to reduce their dimensions with equivalent treatment or even to increase the lifetime of the catalytic converter with equivalent dimensions.

De plus, l'utilisation d'un monolithe diffuseur 7 revêtu de catalyseur, permet d'amorcer les réactions catalytiques qui se poursuivent ensuite dans le monolithe de traitement 8 de façon plus rapide, ce qui augmente encore l'efficacité des catalyseurs 8 et 9.In addition, the use of a diffusing monolith 7 coated with catalyst makes it possible to initiate the catalytic reactions which then continue in the treatment monolith 8 more quickly, which further increases the efficiency of catalysts 8 and 9 .

Enfin, il est possible de prévoir un montage amovible du monolithe diffuseur 7 dans le corps 2, un tel montage autorisant alors un remplacement facile de ce dernier. En effet la face amont des monolithes s'obstrue au cours du temps par des particules solides issues de l'usure du moteur ou des combustions. Dans le dispositif suivant l'invention ces particules sont piégées par le monolithe diffuseur 7 et n'affectent donc pas le monolithe de traitement 8. Il est ainsi possible de conserver une grande efficacité du dispositif d'échappement pour un coût d'entretien modique puisque seul un élément catalytique de taille modeste est à remplacer.Finally, it is possible to provide a removable mounting of the diffuser monolith 7 in the body 2, such mounting then allowing easy replacement of the latter. In fact, the upstream face of the monoliths becomes blocked over time by solid particles resulting from engine wear or combustion. In the device according to the invention, these particles are trapped by the diffuser monolith 7 and therefore do not affect the treatment monolith 8. It is thus possible to maintain a high efficiency of the exhaust device for a low maintenance cost since only a small catalytic element needs to be replaced.

Les dimensions du monolithe 7 et de la cavité 10 sont ajustées à chaque ligne d'échappement par des séries de mesures aux bancs d'essais pour qu'en fonctionnant des débits de gaz circulant à travers le dispositif d'échappement, ils présentent la meilleure diffusion possible.The dimensions of the monolith 7 and of the cavity 10 are adjusted to each exhaust line by series of measurements on the test benches so that by operating the gas flow rates flowing through the exhaust device, they have the best possible diffusion.

Bien entendu, l'invention n'est nullement limitée aux modes de réalisation décrits et illustrés qui n'ont été donnés qu'à titre d'exemples.Of course, the invention is in no way limited to the embodiments described and illustrated which have been given only by way of examples.

Au contraire, l'invention comprend tous les équivalents techniques des moyens décrits ainsi que leurs combinaisons si celles-ci sont effectuées suivant son esprit.On the contrary, the invention includes all the technical equivalents of the means described and their combinations if these are carried out according to the spirit.

Ainsi le dispositif d'échappement suivant l'invention concerne aussi bien les monolithes céramiques que les monolithes métalliques.Thus the exhaust device according to the invention relates to both ceramic monoliths and metal monoliths.

Ainsi le dispositif d'échappement suivant l'invention peut ne comporter qu'un monolithe diffuseur 7 et un monolithe de traitement, ce dernier jouant alors le rôle des deux monolithes de traitement 8 et 9 précédemment décrits.Thus the exhaust device according to the invention may comprise only a diffuser monolith 7 and a treatment monolith, the latter then playing the role of the two treatment monoliths 8 and 9 previously described.

De même, on peut prévoir l'utilisation d'une pluralité de monolithes diffuseurs distincts 7 disposés en amont du ou des monolithes de traitement.8 et 9.Likewise, provision may be made for the use of a plurality of separate diffuser monoliths 7 arranged upstream of the treatment monolith (s). 8 and 9.

Claims (6)

[1] Dispositif d'échappement pour moteur à combustion interne pour épurer les gaz d'échappement comportant une enveloppe destinée à être raccordée à la ligne d'échappement du moteur et présentant un corps cylindrique (2), des extrémités d'entrée (3) et de sortie (4) tronconiques respectivement divergente et convergente, ladite enveloppe contenant au moins un monolithe pour le traitement des gaz (8,9) comportant de multiples canaux disposés axialement et revêtus de substances catalytiques, caractérisé en ce que des moyens diffuseurs (7,10) sont disposés en amont du monolithe de traitement (8,9) dans le sens de l'écoulement des gaz pour assurer la distribution des gaz d'échappement sur la totalité de la section transversale du monolithe (8,9), lesdits moyens diffuseurs étant constitués par au moins un monolithe (7) de dimension axiale réduite par rapport à la dimension axiale du monolithe de traitement (8,9) et par une cavité libre adjacente (10) s'étendant entre ce dernier et le monolithe de traitement (8,9). [1] Exhaust device for internal combustion engine to purify exhaust gas comprising a casing intended to be connected to the engine exhaust line and having a cylindrical body (2), inlet ends (3 ) and respectively frustoconical diverging and converging outlet (4), said envelope containing at least one monolith for the treatment of gases (8, 9) comprising multiple channels arranged axially and coated with catalytic substances, characterized in that diffusing means ( 7.10) are arranged upstream of the treatment monolith (8.9) in the direction of the gas flow to ensure the distribution of the exhaust gases over the entire cross section of the monolith (8.9), said diffusing means being constituted by at least one monolith (7) of reduced axial dimension compared to the axial dimension of the treatment monolith (8,9) and by an adjacent free cavity (10) extending in be the latter and the processing monolith (8,9). [2] Dispositif d'échappement pour moteur à combustion interne selon la revendication 1, caractérisé en ce que la longueur axiale du monolithe diffuseur (7) est inférieure au 1/4 de la longueur axiale totale des monolithes (7,8,9) présents dans ladite enveloppe. [2] Exhaust device for internal combustion engine according to claim 1, characterized in that the axial length of the diffuser monolith (7) is less than 1/4 of the total axial length of the monoliths (7,8,9) present in said envelope. [3] Dispositif d'échappement pour moteur à combustion interne selon l'une quelconque des revendications 1 à 2, caractérisé en ce que ledit monolithe de traitement (8,9) est logé à l'intérieur du corps cylindrique (2) et en ce que lesdits moyens diffuseurs (7,10) sont également disposés à l'intérieur du corps cylindrique (2). [3] Exhaust device for internal combustion engine according to any one of claims 1 to 2, characterized in that said treatment monolith (8,9) is housed inside the cylindrical body (2) and in that said diffusing means (7, 10) are also arranged inside the cylindrical body (2). [4] Dispositif d'échappement pour moteur à combustion interne selon l'une quelconque des revendications 1 à 3, caractérisé en ce que deux monolithes de traitement (8 et 9) sont disposés en aval desdits moyens diffuseurs (7,10). [4] Exhaust device for internal combustion engine according to any one of claims 1 to 3, characterized in that two treatment monoliths (8 and 9) are arranged downstream of said diffusing means (7,10). [5] Dispositif d'échappement pour moteur à combustion interne selon l'une quelconque des revendications 1 à 4, caractérisé en ce que la dimension axiale du monolithe (7) est comprise entre 10 et 50 mm. [5] Exhaust device for internal combustion engine according to any one of claims 1 to 4, characterized in that the axial dimension of the monolith (7) is between 10 and 50 mm. [6] Dispositif d'échappement pour moteur à combustion interne selon l'une quelconque des revendications 1 à 5, caractérisé en ce que le monolithe diffuseur (7) est revêtu de substances catalytiques et participe au traitement des gaz. [6] Exhaust device for internal combustion engine according to any one of claims 1 to 5, characterized in that the diffuser monolith (7) is coated with catalytic substances and participates in the treatment of gases.
EP19930402138 1992-09-04 1993-09-02 Exhaust device for internal combustion engines Revoked EP0592258B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9210554 1992-09-04
FR9210554A FR2695431B1 (en) 1992-09-04 1992-09-04 Exhaust device for internal combustion engine.

Publications (2)

Publication Number Publication Date
EP0592258A1 true EP0592258A1 (en) 1994-04-13
EP0592258B1 EP0592258B1 (en) 1997-11-05

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Application Number Title Priority Date Filing Date
EP19930402138 Revoked EP0592258B1 (en) 1992-09-04 1993-09-02 Exhaust device for internal combustion engines

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EP (1) EP0592258B1 (en)
DE (1) DE69315034T2 (en)
ES (1) ES2108841T3 (en)
FR (1) FR2695431B1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2428964A1 (en) * 1974-06-15 1976-01-02 Bosch Gmbh Robert Reactor insert for exhaust gas detoxification - with conically tapering inlet end
US4072471A (en) * 1974-05-28 1978-02-07 Mobil Oil Corporation Catalytic converter for removing noxious components from a gaseous stream
EP0256416A1 (en) * 1986-08-07 1988-02-24 Leistritz Aktiengesellschaft Exhaust gas cleaning device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4072471A (en) * 1974-05-28 1978-02-07 Mobil Oil Corporation Catalytic converter for removing noxious components from a gaseous stream
DE2428964A1 (en) * 1974-06-15 1976-01-02 Bosch Gmbh Robert Reactor insert for exhaust gas detoxification - with conically tapering inlet end
EP0256416A1 (en) * 1986-08-07 1988-02-24 Leistritz Aktiengesellschaft Exhaust gas cleaning device

Also Published As

Publication number Publication date
DE69315034T2 (en) 1998-04-23
ES2108841T3 (en) 1998-01-01
DE69315034D1 (en) 1997-12-11
EP0592258B1 (en) 1997-11-05
FR2695431A1 (en) 1994-03-11
FR2695431B1 (en) 1994-10-14

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