WO2015132491A1 - Three-way catalyst - Google Patents

Three-way catalyst Download PDF

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Publication number
WO2015132491A1
WO2015132491A1 PCT/FR2015/050308 FR2015050308W WO2015132491A1 WO 2015132491 A1 WO2015132491 A1 WO 2015132491A1 FR 2015050308 W FR2015050308 W FR 2015050308W WO 2015132491 A1 WO2015132491 A1 WO 2015132491A1
Authority
WO
WIPO (PCT)
Prior art keywords
way catalyst
catalyst
elemental
way
internal combustion
Prior art date
Application number
PCT/FR2015/050308
Other languages
French (fr)
Inventor
Pascal Climaud
Vincent Souchon
Julien Lacoste
Alejandro YARCE
Original Assignee
Peugeot Citroen Automobiles Sa
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 Peugeot Citroen Automobiles Sa filed Critical Peugeot Citroen Automobiles Sa
Priority to CN201580012100.9A priority Critical patent/CN106414929B/en
Priority to EP15706900.6A priority patent/EP3114330A1/en
Publication of WO2015132491A1 publication Critical patent/WO2015132491A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • 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
    • F01N3/101—Three-way catalysts
    • 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
    • F01N13/0093—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 of the same type
    • 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
    • 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
    • F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
    • F01N3/2807—Metal other than sintered metal
    • 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
    • F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
    • F01N3/2825—Ceramics
    • 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
    • F01N2590/00—Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines
    • F01N2590/11—Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines for hybrid vehicles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the invention relates to a three-way catalyst which is capable of carrying out three distinct reactions, including a reduction reaction of nitrogen oxides in nitrogen and carbon dioxide, oxidation of carbon monoxide to carbon dioxide and an oxidation of hydrocarbons unburned carbon dioxide and water and which is intended to equip an exhaust line which is provided with an internal combustion engine of a motor vehicle.
  • a hybrid motor vehicle is equipped with an internal combustion engine to provide for its displacement.
  • the hybrid motor vehicle is also equipped with an auxiliary means of propulsion of the motor vehicle, such as an electric motor or the like.
  • the internal combustion engine generates exhaust gases that are discharged to an outside environment outside the internal combustion engine via an exhaust line.
  • the exhaust gases comprise nitrogen oxides which it is desirable to reduce prior to their discharge to the external environment.
  • the exhaust gases also comprise carbon monoxide which it is desirable to oxidize prior to their evacuation to the external environment.
  • the exhaust gases finally comprise unburned hydrocarbons which it is desirable to oxidize prior to their evacuation to the external environment.
  • WO2013153081 discloses a three-way catalyst within which three distinct reactions are carried out, including a reduction reaction of nitrogen oxides in nitrogen and carbon dioxide, oxidation of carbon monoxide to carbon dioxide. carbon and oxidation of unburned hydrocarbons to carbon dioxide and water.
  • An object of the present invention is to provide a three-way catalyst which makes it possible to carry out three distinct reactions, including an oxidation reduction reaction.
  • the three-way catalyst equipping an exhaust line which is provided with an engine an internal combustion engine equipping a hybrid motor vehicle, the three-way catalyst being effective, including after stopping the internal combustion engine of the hybrid vehicle, the three-way catalyst is lightweight, compact, simple to perform and inexpensive.
  • a catalyst of the present invention is a three-way catalyst which is capable of carrying out three distinct reactions, including a reduction reaction of nitrogen oxides in nitrogen and carbon dioxide, oxidation of carbon monoxide to carbon dioxide. carbon and an oxidation of hydrocarbons unburned carbon dioxide and water and which is intended to equip an exhaust line which is provided with an internal combustion engine of a motor vehicle.
  • the three-way catalyst comprises a first elemental three-way catalyst which comprises a metal substrate and a second elemental three-way catalyst which comprises a ceramic substrate.
  • the invention is particularly advantageous for the operating modes of the thermal engines imposing repeated stops and restarts, which is the case, in particular, hybrid vehicles with propulsion mode using a heat engine and an electric machine, so-called “STT” engines for "Stop and Star” in English or automatic shutdown and restart in French, as well as for so-called free wheeling modes of operation ("free wheeling" in English).
  • the metal substrate can very quickly rise in temperature in contact with the exhaust gas at each start of the engine, because of its conductive metal nature, and therefore it can thermally initiate the three-way catalyst that it supports earlier than a ceramic type substrate, weakly thermal conductor.
  • the catalyst supported by the ceramic substrate takes an increasingly important part in the catalysis work: combining the two substrates reveals a synergy, one "taking" the relay of the other depending on the engine phase (starting or stabilized taxiing phase).
  • This advantage is very important, especially to meet the future Chinese standard Beijing 6, which imposes a rolling cycle incorporating a stop engine.
  • the first elemental three-way catalyst and the second elemental three-way catalyst are housed inside a respective envelope.
  • the first basic three-way catalyst and the second elemental three-way catalyst are housed inside a common enclosure.
  • the first elemental three-way catalyst is free of casing.
  • the substrate being metallic, it can be designed to integrate a metal outer envelope, it does not need a separate additional envelope. It can thus be connected directly to the exhaust line, without the need to be arranged in a separate envelope, itself to connect to the line.
  • the first elemental three-way catalyst and the second elemental three-way catalyst are preferably spaced from each other by a non-zero distance.
  • the volume of the first catalyst and the volume of the second catalyst are defined according to the following distribution: - between 15 and 35% by volume for the first catalyst, especially in the vicinity of 25%, and - between 85 and 65 % by volume for the second catalyst, especially in the vicinity of 75%.
  • the catalyst on metal substrate is effective very quickly after starting the engine, since it rises quickly in temperature and it has at the beginning only a small flow of exhaust gas to be treated, its "low" size relative to the ceramic substrate is then not penalizing since there is less gas to be treated in stabilized rolling regime, for which the catalyst on ceramic substrate "takes over", for example after 100 seconds.
  • the catalyst comprises a formulation of one or more compounds or elements with photocatalytic properties, which is supported by a substrate (for example by impregnation in a known manner). It is therefore possible, with respect to the size of the catalyst, to refer to the catalyst or the substrate that is part of it in the broad sense of an organ.
  • An exhaust line of the present invention is an exhaust line housing such a three-way catalyst.
  • An internal combustion engine of the present invention is an internal combustion engine equipped with such an exhaust line.
  • a motor vehicle of the present invention is a motor vehicle equipped with such an internal combustion engine.
  • the motor vehicle is for example equipped with an auxiliary means of propulsion.
  • the motor vehicle is for example equipped with a stop-start system.
  • Figures 1 to 3 are schematic illustrations of respective exhaust lines housing a three-way catalyst of the present invention.
  • a hybrid motor vehicle is equipped with an internal combustion engine 1 to provide for its displacement.
  • the internal combustion engine 1 is preferably a gasoline spark ignition engine.
  • the internal combustion engine 1 generates pollutants including nitrogen oxides, carbon monoxide and unburned hydrocarbons.
  • the hybrid motor vehicle is equipped with an auxiliary means of propulsion, not shown, such as an electric motor or the like.
  • the internal combustion engine 1 generates exhaust gases 2 which are discharged to an external environment 3 out of the internal combustion engine 1 via an exhaust line 4.
  • the exhaust gases 2 include oxides of nitrogen, carbon monoxide and unburnt hydrocarbons whose content must be minimized prior to their discharge to the external environment 3.
  • the exhaust line 4 houses a post-treatment system
  • the aftertreatment system 5 comprises a three-way catalyst 8 which makes it possible to carry out three distinct reactions, including a reduction reaction of nitrogen oxides with nitrogen and carbon dioxide, an oxidation of the carbon monoxide to carbon dioxide and oxidation of unburned hydrocarbons to carbon dioxide and water.
  • the three-way catalyst 8 comprises a cylindrical or ovoid-shaped substrate which is impregnated with a chemical compound, commonly called “washcoat” for coating.
  • the chemical compound contains precious metals to catalyze oxidation reactions of carbon monoxide and unburned hydrocarbons and reduction of nitrogen oxides.
  • the three-way catalyst 8 needs to be brought to a threshold temperature to be effective. It reaches 50% efficiency between 300 ° C and 350 ° C and reaches its full efficiency from 600 ° C. To optimize a rise in temperature of the three-way catalyst 8, the latter is positioned inside the exhaust line 4 directly at the outlet of the internal combustion engine 1.
  • the three-way catalyst 8 rises in temperature more or less rapidly, under the effect of the exhaust gas 2 which pass through it, even under the effect of a three-way catalytic heater 8.
  • the three-way catalyst 8 comprises a first elemental three-way catalyst 8a which comprises a metal substrate and a second elemental three-way catalyst 8b which comprises a ceramic substrate.
  • the first three-way elementary catalyst 8a with a metal substrate has a low thermal inertia and rises rapidly in temperature, which allows efficiency very early in a regulatory measurement cycle and in customer operation and allows optimized conversion of pollutants. as soon as possible.
  • the metal substrate is coated with said precious metal-containing chemical compound which catalyzes the oxidation reactions of carbon monoxide and unburned hydrocarbons and reduction of nitrogen oxides.
  • the second elemental three-way catalyst 8b with ceramic substrate, cordierite for example or the like, has a relatively high thermal inertia and therefore requires more time to increase in temperature and start to convert the pollutants later in a cycle regulatory measure or in customer operation.
  • the ceramic substrate is also coated with said precious metal-containing chemical compound that catalyzes the oxidation reactions of carbon monoxide and unburned hydrocarbons and reduction of nitrogen oxides.
  • a motor vehicle has operating phases during which the exhaust gas 2 is not particularly hot, this may be the case during foot lifts during which a fuel injection inside the internal combustion engine 1 is cut off. There are also operating phases during which the internal combustion engine 1 does not work, for example, when the motor vehicle is equipped with an automatic stop-start device commonly known by the name of "Stop & Start Agriculture This is all the more relevant for a hybrid motor vehicle for which the internal combustion engine 1 is associated with an auxiliary propulsion means of the electric motor type or to another type of engine (compressed gas for example).
  • the pollution control of the exhaust gas 2 is optimized in all cases of operation of the internal combustion engine 1.
  • the first elemental catalyst 8a 8a low thermal inertia rises in temperature quickly and can be treated by minimizing polluting emissions quickly.
  • the second 8b elementary three-way catalyst with significant thermal inertia rises in temperature more slowly and reaches full efficiency after a few seconds.
  • the first three-way elementary catalyst 8a with low thermal inertia rapidly decreases in temperature and loses its efficiency, but the second elemental three-way catalyst 8b with high thermal inertia retains a high temperature which makes it possible to treat all the pollutant emissions when the engine is restarted. internal combustion 1 or when resuming fuel injection.
  • the first elementary three-way catalyst 8a and the second elemental three-way catalyst 8b are housed inside a respective envelope 1 1a, 1 1b.
  • the envelopes 11a, 11b each comprise, for example, a layer of an inorganic endothermic material comprising ceramic fibers.
  • the first three-way elementary catalyst 8a and the second three-way elementary catalyst 8b are housed inside a common enclosure 12.
  • the common enclosure 12 comprises by also a layer of an inorganic endothermic material comprising ceramic fibers.
  • the first basic three-way catalyst 8a and the second three-way elementary catalyst 8b are for example spaced from each other by a non-zero distance D which is between 10 mm and 50 mm. These arrangements make it possible to avoid a propagation of vibrations between the first elementary three-way catalyst 8a and the second elementary three-way catalyst 8b.
  • These arrangements also allow differential expansion of the first three-way elemental catalyst 8a and the second basic three-way catalyst 8b without altering one or the other of the elementary catalysts 8a, 8b.
  • the exhaust line 4 also houses a probe 9 upstream of the three-way catalyst 8 and / or downstream of the three-way catalyst 8, in a direction of flow 6 of the exhaust gases 2 inside the exhaust line 4.
  • the first elemental three-way catalyst 8a is free of envelope.

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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)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Catalysts (AREA)

Abstract

The invention relates to a three-way catalyst (8) which is capable of carrying out three separate reactions, including a reduction reaction of nitrogen oxides to give dinitrogen and carbon dioxide, an oxidation of carbon monoxide to give carbon dioxide and an oxidation of unburned hydrocarbons to give carbon dioxide and water and which is intended to equip an exhaust line (4) with which an internal combustion engine (1) of a motor vehicle is provided. The three-way catalyst (8) comprises a first individual three-way catalyst (8a), which comprises a metal substrate and a second individual three-way catalyst (8b) which comprises a ceramic substrate.

Description

CATALYSEUR TROIS VOIES.  CATALYST THREE WAYS.
[0001 ] L'invention porte sur un catalyseur trois voies qui est apte à réaliser trois réactions distinctes, dont une réaction de réduction d'oxydes d'azote en diazote et dioxyde de carbone, une oxydation du monoxyde de carbone en dioxyde de carbone et une oxydation d'hydrocarbures imbrulés en dioxyde de carbone et en eau et qui est destiné à équiper une ligne d'échappement dont est pourvu un moteur à combustion interne d'un véhicule automobile. The invention relates to a three-way catalyst which is capable of carrying out three distinct reactions, including a reduction reaction of nitrogen oxides in nitrogen and carbon dioxide, oxidation of carbon monoxide to carbon dioxide and an oxidation of hydrocarbons unburned carbon dioxide and water and which is intended to equip an exhaust line which is provided with an internal combustion engine of a motor vehicle.
[0002] Un véhicule automobile hybride est équipé d'un moteur à combustion interne pour pourvoir à son déplacement. Le véhicule automobile hybride est aussi équipé d'un moyen annexe de propulsion du véhicule automobile, tel qu'un moteur électrique ou analogue. [0002] A hybrid motor vehicle is equipped with an internal combustion engine to provide for its displacement. The hybrid motor vehicle is also equipped with an auxiliary means of propulsion of the motor vehicle, such as an electric motor or the like.
[0003] Le moteur à combustion interne génère des gaz d'échappement qui sont évacués vers un environnement extérieur hors du moteur à combustion interne par l'intermédiaire d'une ligne d'échappement. Les gaz d'échappement comprennent des oxydes d'azote qu'il est souhaitable de réduire préalablement à leur évacuation vers l'environnement extérieur. Les gaz d'échappement comprennent aussi du monoxyde de carbone qu'il est souhaitable d'oxyder préalablement à leur évacuation vers l'environnement extérieur. Les gaz d'échappement comprennent enfin des hydrocarbures imbrûlés qu'il est souhaitable d'oxyder préalablement à leur évacuation vers l'environnement extérieur. The internal combustion engine generates exhaust gases that are discharged to an outside environment outside the internal combustion engine via an exhaust line. The exhaust gases comprise nitrogen oxides which it is desirable to reduce prior to their discharge to the external environment. The exhaust gases also comprise carbon monoxide which it is desirable to oxidize prior to their evacuation to the external environment. The exhaust gases finally comprise unburned hydrocarbons which it is desirable to oxidize prior to their evacuation to the external environment.
[0004] On connaît par le document WO2013153081 un catalyseur trois voies à l'intérieur duquel se réalisent trois réactions distinctes, dont une réaction de réduction des oxydes d'azote en diazote et dioxyde de carbone, une oxydation du monoxyde de carbone en dioxyde de carbone et une oxydation des hydrocarbures imbrulés en dioxyde de carbone et en eau. [0004] WO2013153081 discloses a three-way catalyst within which three distinct reactions are carried out, including a reduction reaction of nitrogen oxides in nitrogen and carbon dioxide, oxidation of carbon monoxide to carbon dioxide. carbon and oxidation of unburned hydrocarbons to carbon dioxide and water.
[0005] Pour être efficace le catalyseur trois voies nécessite que les gaz d'échappement soient portés à une certaine température pour que le catalyseur trois voies lui-même atteigne une température-seuil. Or, le moteur à combustion interne d'un véhicule automobile hybride est fréquemment mis à l'arrêt pour être suppléé par le moyen annexe de propulsion. Dans ce cas, la ligne d'échappement ne canalise plus une circulation de gaz d'échappement ce qui induit un refroidissement préjudiciable du catalyseur trois voies. [0006] Un but de la présente invention est de proposer un catalyseur trois voies qui permet de réaliser trois réactions distinctes, dont une réaction de réduction d'oxydes d'azote en diazote et dioxyde de carbone, une oxydation du monoxyde de carbone en dioxyde de carbone et une oxydation d'hydrocarbures imbrulés en dioxyde de carbone et en eau, le catalyseur trois voies équipant une ligne d'échappement dont est pourvu un moteur à combustion interne équipant un véhicule automobile hybride, le catalyseur trois voies étant efficace, y compris après une mise à l'arrêt du moteur à combustion interne du véhicule hybride, le catalyseur trois voies étant léger, compact, simple à réaliser et peu coûteux. To be effective the three-way catalyst requires that the exhaust gas be brought to a certain temperature so that the three-way catalyst itself reaches a threshold temperature. However, the internal combustion engine of a hybrid motor vehicle is frequently stopped to be supplemented by the auxiliary means of propulsion. In this case, the exhaust line no longer channels an exhaust gas circulation which induces a harmful cooling of the three-way catalyst. An object of the present invention is to provide a three-way catalyst which makes it possible to carry out three distinct reactions, including an oxidation reduction reaction. nitrogen in nitrogen and carbon dioxide, oxidation of carbon monoxide to carbon dioxide and oxidation of unburned hydrocarbons to carbon dioxide and water, the three-way catalyst equipping an exhaust line which is provided with an engine an internal combustion engine equipping a hybrid motor vehicle, the three-way catalyst being effective, including after stopping the internal combustion engine of the hybrid vehicle, the three-way catalyst is lightweight, compact, simple to perform and inexpensive.
[0007] Un catalyseur de la présente invention est un catalyseur trois voies qui est apte à réaliser trois réactions distinctes, dont une réaction de réduction d'oxydes d'azote en diazote et dioxyde de carbone, une oxydation du monoxyde de carbone en dioxyde de carbone et une oxydation d'hydrocarbures imbrulés en dioxyde de carbone et en eau et qui est destiné à équiper une ligne d'échappement dont est pourvu un moteur à combustion interne d'un véhicule automobile. A catalyst of the present invention is a three-way catalyst which is capable of carrying out three distinct reactions, including a reduction reaction of nitrogen oxides in nitrogen and carbon dioxide, oxidation of carbon monoxide to carbon dioxide. carbon and an oxidation of hydrocarbons unburned carbon dioxide and water and which is intended to equip an exhaust line which is provided with an internal combustion engine of a motor vehicle.
[0008] Selon la présente invention, le catalyseur trois voies comprend un premier catalyseur trois voies élémentaire qui comporte un substrat métallique et un deuxième catalyseur trois voies élémentaire qui comporte un substrat céramique. According to the present invention, the three-way catalyst comprises a first elemental three-way catalyst which comprises a metal substrate and a second elemental three-way catalyst which comprises a ceramic substrate.
[0009] L'invention est particulièrement avantageuse pour les modes de fonctionnement des moteurs thermiques imposant des arrêts et des redémarrages répétés, ce qui est le cas, notamment, des véhicules hybrides avec mode de propulsion utilisant un moteur thermique et une machine électrique, des moteurs dits « STT » pour « Stop and Star » en anglais ou encore arrête et redémarrage automatiques en français, ainsi que pour les modes de fonctionnement dits en roue libre (« free wheeling » en anglais). En effet, le substrat métallique peut très vite monter en température au contact des gaz d'échappement à chaque démarrage du moteur, du fait de sa nature métallique conductrice, et donc il peut amorcer thermiquement le catalyseur trois voies qu'il supporte plus tôt qu'un substrat de type céramique, faiblement conducteur thermique. Une fois la phase de démarrage du moteur terminée, le catalyseur supporté par le substrat céramique prend une part de plus en plus importante dans le travail de catalyse : combiner les deux substrats révèle une synergie, l'un « prenant » le relais de l'autre en fonction de la phase du moteur (démarrage ou phase de roulage stabilisée). Cet avantage est très important, notamment pour respecter la future norme chinoise Beijing 6, qui impose un cycle de roulage intégrant un arrêt du moteur. [0010] Selon une première variante de réalisation, le premier catalyseur trois voies élémentaire et le deuxième catalyseur trois voies élémentaire sont logés à l'intérieur d'une enveloppe respective. The invention is particularly advantageous for the operating modes of the thermal engines imposing repeated stops and restarts, which is the case, in particular, hybrid vehicles with propulsion mode using a heat engine and an electric machine, so-called "STT" engines for "Stop and Star" in English or automatic shutdown and restart in French, as well as for so-called free wheeling modes of operation ("free wheeling" in English). Indeed, the metal substrate can very quickly rise in temperature in contact with the exhaust gas at each start of the engine, because of its conductive metal nature, and therefore it can thermally initiate the three-way catalyst that it supports earlier than a ceramic type substrate, weakly thermal conductor. Once the engine start phase is over, the catalyst supported by the ceramic substrate takes an increasingly important part in the catalysis work: combining the two substrates reveals a synergy, one "taking" the relay of the other depending on the engine phase (starting or stabilized taxiing phase). This advantage is very important, especially to meet the future Chinese standard Beijing 6, which imposes a rolling cycle incorporating a stop engine. According to a first variant embodiment, the first elemental three-way catalyst and the second elemental three-way catalyst are housed inside a respective envelope.
[001 1 ] Selon une deuxième variante de réalisation, le premier catalyseur trois voies élémentaire et le deuxième catalyseur trois voies élémentaire sont logés à l'intérieur d'une enceinte commune. [001 1] According to a second embodiment, the first basic three-way catalyst and the second elemental three-way catalyst are housed inside a common enclosure.
[0012] Selon une troisième variante de réalisation, le premier catalyseur trois voies élémentaire est exempt d'enveloppe. According to a third embodiment, the first elemental three-way catalyst is free of casing.
[0013] En effet, le substrat étant métallique, il peut être conçu de façon à intégrer une enveloppe extérieure métallique, il n'a pas besoin d'une enveloppe distincte supplémentaire. Il peut ainsi être raccordé directement à la ligne d'échappement, sans avoir besoin d'être disposé dans une enveloppe distincte, elle-même à raccorder à la ligne. Il y a une autre avantage à cette configuration, outre la simplicité de montage sur la ligne et le cout d'une enveloppe supplémentaire : avec un raccord direct il n'est pas besoin de prévoir entre le substrat et une enveloppe distincte un matériau qui vient absorber les vibrations, et qui est généralement prévu pour faire l'interface entre les substrats de type céramiques et leurs enveloppes externes : on n'a plus besoin de ce type de matériau d'interface, ce qui présente aussi un avantage en termes de montage et de cout , mais cela permet également de choisir une section de substrat métallique plus grande à iso encombrement sur ligne (puisqu'on n'a plus d'épaisseur de matériau d'interface et d'enveloppe extérieure). Indeed, the substrate being metallic, it can be designed to integrate a metal outer envelope, it does not need a separate additional envelope. It can thus be connected directly to the exhaust line, without the need to be arranged in a separate envelope, itself to connect to the line. There is another advantage to this configuration, besides the simplicity of mounting on the line and the cost of an additional envelope: with a direct connection there is no need to provide between the substrate and a separate envelope a material that comes absorb the vibrations, and which is generally intended to interface between the ceramic-type substrates and their outer shells: there is no longer any need for this type of interface material, which also has an advantage in terms of mounting and cost, but it also allows to choose a larger metal substrate section iso congestion line (since there is more thickness of interface material and outer casing).
[0014] Le premier catalyseur trois voies élémentaire et le deuxième catalyseur trois voies élémentaire sont préférentiellement espacés l'un de l'autre d'une distance non nulle. The first elemental three-way catalyst and the second elemental three-way catalyst are preferably spaced from each other by a non-zero distance.
[0015] De préférence, le volume du premier catalyseur et le volume du deuxième catalyseur sont définis selon la répartition suivante : - entre 15 et 35 % en volume pour le premier catalyseur, notamment au voisinage de 25%, et - entre 85 et 65% en volume pour le deuxième catalyseur, notamment au voisinage de 75%. Preferably, the volume of the first catalyst and the volume of the second catalyst are defined according to the following distribution: - between 15 and 35% by volume for the first catalyst, especially in the vicinity of 25%, and - between 85 and 65 % by volume for the second catalyst, especially in the vicinity of 75%.
[0016] En effet, on peut doser précisément la part de la contribution de chacun des catalyseurs, pour que l'ensemble réponde aussi vite que possible après démarrage, puis dans la durée. On peut naturellement jouer sur le taux d'imprégnation en catalyseur de chacun des substrats, et/ou du dimensionnement de ceux-ci, souvent quantifié sous forme d'un volume. Ici, par exemple à iso-concentration en substances catalytiques, on peut considérer qu'une proportion volumique de l'ordre de un quart (substrat métallique) / trois quarts (substrat céramique) donne de bons résultats, avec un effet catalytique dès 20 secondes après le démarrage. : le catalyseur sur substrat métallique est efficace très vite après le démarrage du moteur, puisqu'il monte vite en température et qu'il n'a au début qu'un petit débit de gaz d'échappement à traiter, sa « faible » taille par rapport au substrat céramique n'étant alors pas pénalisante puisqu'il y a moins de gaz à traiter qu'en régime de roulage stabilisé, pour lequel le catalyseur sur substrat céramique « prend le relais », par exemple dès après 100 secondes. [0017] A titre d'illustration, on peut ainsi prévoir 0,7 litre de substrat métallique pour 2,5 litres de substrat céramique. Indeed, it is possible to accurately measure the contribution of each of the catalysts, so that the whole responds as quickly as possible after startup, and then in the long term. One can naturally play on the rate of impregnation catalyst of each of the substrates, and / or the dimensioning thereof, often quantified in form of a volume. Here, for example with iso-concentration of catalytic substances, it can be considered that a proportion by volume of the order of a quarter (metal substrate) / three quarters (ceramic substrate) gives good results, with a catalytic effect of 20 seconds after startup. : the catalyst on metal substrate is effective very quickly after starting the engine, since it rises quickly in temperature and it has at the beginning only a small flow of exhaust gas to be treated, its "low" size relative to the ceramic substrate is then not penalizing since there is less gas to be treated in stabilized rolling regime, for which the catalyst on ceramic substrate "takes over", for example after 100 seconds. By way of illustration, it is thus possible to provide 0.7 liter of metal substrate for 2.5 liters of ceramic substrate.
[0018] Dans tout le présent texte, le catalyseur comporte à proprement dit une formulation d'un ou plusieurs composés ou éléments à propriétés photocatalytiques, qui est supportée par un substrat (par imprégnation par exemple, de façon connue). On peut donc indifféremment, en ce qui concerne le dimensionnement du catalyseur parler du catalyseur ou du substrat qui en fait partie au sens large d'un organe. Throughout the present text, the catalyst comprises a formulation of one or more compounds or elements with photocatalytic properties, which is supported by a substrate (for example by impregnation in a known manner). It is therefore possible, with respect to the size of the catalyst, to refer to the catalyst or the substrate that is part of it in the broad sense of an organ.
[0019] Une ligne d'échappement de la présente invention est une ligne d'échappement logeant un tel catalyseur trois voies. An exhaust line of the present invention is an exhaust line housing such a three-way catalyst.
[0020] Un moteur à combustion interne de la présente invention est un moteur à combustion interne équipé d'une telle ligne d'échappement. [0020] An internal combustion engine of the present invention is an internal combustion engine equipped with such an exhaust line.
[0021 ] Un véhicule automobile de la présente invention est un véhicule automobile équipé d'un tel moteur à combustion interne. A motor vehicle of the present invention is a motor vehicle equipped with such an internal combustion engine.
[0022] Le véhicule automobile est par exemple équipé d'un moyen annexe de propulsion. [0023] Le véhicule automobile est par exemple équipé d'un système d'arrêt-démarrage. The motor vehicle is for example equipped with an auxiliary means of propulsion. The motor vehicle is for example equipped with a stop-start system.
[0024] D'autres caractéristiques et avantages de la présente invention apparaîtront à la lecture de la description qui va en être faite d'exemples de réalisation, en relation avec les figures des planches annexées, dans lesquelles : Other features and advantages of the present invention will appear on reading the description which will be made of embodiments, in connection with the figures of the attached plates, in which:
[0025] Les figures 1 à 3 sont des illustrations schématiques de lignes d'échappement respectives logeant un catalyseur trois voies de la présente invention. [0026] Sur les figures, un véhicule automobile hybride est équipé d'un moteur à combustion interne 1 pour pourvoir à son déplacement. Le moteur à combustion interne 1 est préférentiellement un moteur essence à allumage commandé. Le moteur à combustion interne 1 génère des polluants dont des oxydes d'azote, du monoxyde de carbone et des hydrocarbures imbrûlés. Le véhicule automobile hybride est équipé d'un moyen annexe de propulsion, non représenté, tel qu'un moteur électrique ou analogue. Figures 1 to 3 are schematic illustrations of respective exhaust lines housing a three-way catalyst of the present invention. In the figures, a hybrid motor vehicle is equipped with an internal combustion engine 1 to provide for its displacement. The internal combustion engine 1 is preferably a gasoline spark ignition engine. The internal combustion engine 1 generates pollutants including nitrogen oxides, carbon monoxide and unburned hydrocarbons. The hybrid motor vehicle is equipped with an auxiliary means of propulsion, not shown, such as an electric motor or the like.
[0027] Le moteur à combustion interne 1 génère des gaz d'échappement 2 qui sont évacués vers un environnement extérieur 3 hors du moteur à combustion interne 1 par l'intermédiaire d'une ligne d'échappement 4. Les gaz d'échappement 2 comprennent des oxydes d'azotes, du monoxyde de carbone et des hydrocarbures imbrûlés dont il convient de minimiser la teneur préalablement à leur évacuation vers l'environnement extérieur 3. A cet effet, la ligne d'échappement 4 loge un système de post-traitement 5 des gaz d'échappement 2. Le système de post-traitement 5 comprend un catalyseur trois voies 8 qui permet de réaliser trois réactions distinctes, dont une réaction de réduction d'oxydes d'azote en diazote et dioxyde de carbone, une oxydation du monoxyde de carbone en dioxyde de carbone et une oxydation d'hydrocarbures imbrulés en dioxyde de carbone et en eau. The internal combustion engine 1 generates exhaust gases 2 which are discharged to an external environment 3 out of the internal combustion engine 1 via an exhaust line 4. The exhaust gases 2 include oxides of nitrogen, carbon monoxide and unburnt hydrocarbons whose content must be minimized prior to their discharge to the external environment 3. For this purpose, the exhaust line 4 houses a post-treatment system The aftertreatment system 5 comprises a three-way catalyst 8 which makes it possible to carry out three distinct reactions, including a reduction reaction of nitrogen oxides with nitrogen and carbon dioxide, an oxidation of the carbon monoxide to carbon dioxide and oxidation of unburned hydrocarbons to carbon dioxide and water.
[0028] Le catalyseur trois voies 8 comprend un substrat cylindrique ou de forme ovoïde qui est imprégné d'un composé chimique, couramment appelé « washcoat » pour revêtement. Le composé chimique contient des métaux précieux permettant de catalyser les réactions d'oxydation du monoxyde de carbone et des hydrocarbures imbrûlés et de réduction des oxydes d'azote. The three-way catalyst 8 comprises a cylindrical or ovoid-shaped substrate which is impregnated with a chemical compound, commonly called "washcoat" for coating. The chemical compound contains precious metals to catalyze oxidation reactions of carbon monoxide and unburned hydrocarbons and reduction of nitrogen oxides.
[0029] Le catalyseur trois voies 8 nécessite d'être porté à une température-seuil pour être efficace. Il atteint 50% d'efficacité entre 300 °C et 350 °C environ et atteint sa pleine efficacité à partir de 600 °C. Pour optimiser une montée en température du catalyseur trois voies 8, ce dernier est positionné à l'intérieur de la ligne d'échappement 4 directement en sortie du moteur à combustion interne 1 . The three-way catalyst 8 needs to be brought to a threshold temperature to be effective. It reaches 50% efficiency between 300 ° C and 350 ° C and reaches its full efficiency from 600 ° C. To optimize a rise in temperature of the three-way catalyst 8, the latter is positioned inside the exhaust line 4 directly at the outlet of the internal combustion engine 1.
[0030] Selon le substrat utilisé et l'inertie de ce substrat, le catalyseur trois voies 8 monte en température plus ou moins rapidement, sous l'effet des gaz d'échappement 2 qui le traversent, voire sous l'effet d'un dispositif de chauffage du catalyseur trois voies 8. [0031 ] Selon la présente invention, le catalyseur trois voies 8 comprend un premier catalyseur trois voies élémentaire 8a qui comporte un substrat métallique et un deuxième catalyseur trois voies élémentaire 8b qui comporte un substrat céramique. Depending on the substrate used and the inertness of this substrate, the three-way catalyst 8 rises in temperature more or less rapidly, under the effect of the exhaust gas 2 which pass through it, even under the effect of a three-way catalytic heater 8. According to the present invention, the three-way catalyst 8 comprises a first elemental three-way catalyst 8a which comprises a metal substrate and a second elemental three-way catalyst 8b which comprises a ceramic substrate.
[0032] Le premier catalyseur trois voies élémentaire 8a avec substrat métallique a une inertie thermique faible et monte en température rapidement, ce qui permet une efficacité très tôt lors d'un cycle de mesure réglementaire et en fonctionnement client et permet une conversion optimisée des polluants au plus tôt. Le substrat métallique est revêtu dudit composé chimique contenant des métaux précieux qui permettent de catalyser les réactions d'oxydation du monoxyde de carbone et des hydrocarbures imbrûlés et de réduction des oxydes d'azote. The first three-way elementary catalyst 8a with a metal substrate has a low thermal inertia and rises rapidly in temperature, which allows efficiency very early in a regulatory measurement cycle and in customer operation and allows optimized conversion of pollutants. as soon as possible. The metal substrate is coated with said precious metal-containing chemical compound which catalyzes the oxidation reactions of carbon monoxide and unburned hydrocarbons and reduction of nitrogen oxides.
[0033] Le deuxième catalyseur trois voies élémentaire 8b avec substrat céramique, en cordiérite par exemple ou analogue, a une inertie thermique relativement importante et nécessite donc plus de temps pour monter en température et commencer à convertir les polluants plus tardivement lors d'un cycle de mesure réglementaire ou en fonctionnement client. Le substrat céramique est également revêtu dudit composé chimique contenant des métaux précieux qui permettent de catalyser les réactions d'oxydation du monoxyde de carbone et des hydrocarbures imbrûlés et de réduction des oxydes d'azote. The second elemental three-way catalyst 8b with ceramic substrate, cordierite for example or the like, has a relatively high thermal inertia and therefore requires more time to increase in temperature and start to convert the pollutants later in a cycle regulatory measure or in customer operation. The ceramic substrate is also coated with said precious metal-containing chemical compound that catalyzes the oxidation reactions of carbon monoxide and unburned hydrocarbons and reduction of nitrogen oxides.
[0034] Un véhicule automobile présente des phases de fonctionnement pendant lesquelles les gaz d'échappement 2 ne sont pas particulièrement chauds, cela peut être le cas lors de levés de pied pendant lesquelles une injection de carburant à l'intérieur du moteur à combustion interne 1 est coupée. Il existe également des phases de fonctionnement pendant lesquelles le moteur à combustion interne 1 ne fonctionne pas, par exemple, lorsque le véhicule automobile est équipé d'un dispositif d'arrêt-démarrage automatique couramment connu sous l'appellation anglo-saxonne « Stop & Start ». Ceci est d'autant plus pertinent pour un véhicule automobile hybride pour lequel le moteur à combustion interne 1 est associé à un moyen de propulsion annexe, du type moteur électrique ou à un autre type de motorisation (gaz comprimé par exemple). A motor vehicle has operating phases during which the exhaust gas 2 is not particularly hot, this may be the case during foot lifts during which a fuel injection inside the internal combustion engine 1 is cut off. There are also operating phases during which the internal combustion engine 1 does not work, for example, when the motor vehicle is equipped with an automatic stop-start device commonly known by the name of "Stop & Start ». This is all the more relevant for a hybrid motor vehicle for which the internal combustion engine 1 is associated with an auxiliary propulsion means of the electric motor type or to another type of engine (compressed gas for example).
[0035] Dans ces cas de non-fonctionnement du moteur à combustion interne 1 , il n'y a pas de gaz d'échappement 2 chauds qui traversent le catalyseur trois voies 8 ou alors ce sont des gaz d'échappement 2 froids. In these cases of non-operation of the internal combustion engine 1, there is no hot exhaust gas 2 through the three-way catalyst 8 or it is cold exhaust 2.
[0036] A partir de l'association du premier catalyseur trois voies élémentaire 8a qui comporte le substrat métallique et du deuxième catalyseur trois voies élémentaire 8b qui comporte le substrat céramique pour former conjointement le catalyseur trois voies 8 de la présente invention, la dépollution des gaz d'échappement 2 est optimisée dans tous les cas de fonctionnement du moteur à combustion interne 1 . From the combination of the first elemental three-way catalyst 8a which comprises the metal substrate and the second elementary three-way catalyst 8b which comprises the ceramic substrate to jointly form the three-way catalyst 8 of the present invention, the pollution control of the exhaust gas 2 is optimized in all cases of operation of the internal combustion engine 1.
[0037] Lors du démarrage du moteur à combustion interne 1 , le premier catalyseur trois voies élémentaire 8a à faible inertie thermique monte en température rapidement et permet de traiter en les minimisant les émissions polluantes rapidement. When starting the internal combustion engine 1, the first elemental catalyst 8a 8a low thermal inertia rises in temperature quickly and can be treated by minimizing polluting emissions quickly.
[0038] Le deuxième catalyseur trois voies élémentaire 8b à inertie thermique importante monte en température plus lentement et atteint sa pleine efficacité après quelques secondes. [0039] Lors de coupures d'injection de carburant ou lors d'arrêts du moteur à combustion interne 1 , dus à la mise en œuvre du dispositif d'arrêt-démarrage et/ou à la mise en œuvre du moyen de propulsion annexe, le premier catalyseur trois voies élémentaire 8a à inertie thermique faible descend en température rapidement et perd son efficacité, mais le deuxième catalyseur trois voies élémentaire 8b à inertie thermique importante conserve une température importante qui permet de traiter toutes les émissions polluantes lors du redémarrage du moteur à combustion interne 1 ou bien lors de la reprise de l'injection de carburant. The second 8b elementary three-way catalyst with significant thermal inertia rises in temperature more slowly and reaches full efficiency after a few seconds. During fuel injection cuts or during shutdowns of the internal combustion engine 1, due to the implementation of the stop-start device and / or the implementation of the auxiliary propulsion means, the first three-way elementary catalyst 8a with low thermal inertia rapidly decreases in temperature and loses its efficiency, but the second elemental three-way catalyst 8b with high thermal inertia retains a high temperature which makes it possible to treat all the pollutant emissions when the engine is restarted. internal combustion 1 or when resuming fuel injection.
[0040] Selon une première variante de réalisation illustrée sur la figure 1 , le premier catalyseur trois voies élémentaire 8a et le deuxième catalyseur trois voies élémentaire 8b sont logés à l'intérieur d'une enveloppe respective 1 1 a, 1 1 b. Les enveloppes 1 1 a,1 1 b comprennent par exemple chacune une couche d'un matériau endothermique inorganique comprenant des fibres céramiques. According to a first embodiment illustrated in Figure 1, the first elementary three-way catalyst 8a and the second elemental three-way catalyst 8b are housed inside a respective envelope 1 1a, 1 1b. The envelopes 11a, 11b each comprise, for example, a layer of an inorganic endothermic material comprising ceramic fibers.
[0041 ] Selon une deuxième variante de réalisation illustrée sur la figure 2, le premier catalyseur trois voies élémentaire 8a et le deuxième catalyseur trois voies élémentaire 8b sont logés à l'intérieur d'une enceinte commune 12. L'enceinte commune 12 comprend par exemple aussi une couche d'un matériau endothermique inorganique comprenant des fibres céramiques. Le premier catalyseur trois voies élémentaire 8a et le deuxième catalyseur trois voies élémentaire 8b sont par exemple espacés l'un de l'autre d'une distance D non nulle qui est comprise entre 10 mm et 50 mm. Ces dispositions permettent d'éviter une propagation de vibrations entre le premier catalyseur trois voies élémentaire 8a et le deuxième catalyseur trois voies élémentaire 8b. Ces dispositions permettent aussi une dilatation différentielle du premier catalyseur trois voies élémentaire 8a et du deuxième catalyseur trois voies élémentaire 8b sans altération de l'un ou de l'autre des catalyseurs élémentaires 8a, 8b. Ces dispositions permettent enfin une interposition d'une sonde 9 entre le premier catalyseur trois voies élémentaire 8a et le deuxième catalyseur trois voies élémentaire 8b, la sonde 9 étant par exemple une sonde à oxygène, dite sonde lambda. Accessoirement, la ligne d'échappement 4 loge aussi une sonde 9 en amont du catalyseur trois voies 8 et/ou en aval du catalyseur trois voies 8, selon un sens d'écoulement 6 des gaz d'échappement 2 à l'intérieur de la ligne d'échappement 4. According to a second variant embodiment illustrated in FIG. 2, the first three-way elementary catalyst 8a and the second three-way elementary catalyst 8b are housed inside a common enclosure 12. The common enclosure 12 comprises by also a layer of an inorganic endothermic material comprising ceramic fibers. The first basic three-way catalyst 8a and the second three-way elementary catalyst 8b are for example spaced from each other by a non-zero distance D which is between 10 mm and 50 mm. These arrangements make it possible to avoid a propagation of vibrations between the first elementary three-way catalyst 8a and the second elementary three-way catalyst 8b. These arrangements also allow differential expansion of the first three-way elemental catalyst 8a and the second basic three-way catalyst 8b without altering one or the other of the elementary catalysts 8a, 8b. These arrangements finally allow an interposition of a probe 9 between the first elemental three-way catalyst 8a and the second elemental three-way catalyst 8b, the probe 9 being for example an oxygen probe, called lambda probe. Incidentally, the exhaust line 4 also houses a probe 9 upstream of the three-way catalyst 8 and / or downstream of the three-way catalyst 8, in a direction of flow 6 of the exhaust gases 2 inside the exhaust line 4.
[0042] Selon une troisième variante de réalisation illustrée sur la figure 3, le premier catalyseur trois voies élémentaire 8a est exempt d'enveloppe. According to a third embodiment shown in Figure 3, the first elemental three-way catalyst 8a is free of envelope.

Claims

Revendications claims
1. Catalyseur trois voies (8) qui est apte à réaliser trois réactions distinctes, dont une réaction de réduction d'oxydes d'azote en diazote et dioxyde de carbone, une oxydation du monoxyde de carbone en dioxyde de carbone et une oxydation d'hydrocarbures imbrulés en dioxyde de carbone et en eau et qui est destiné à équiper une ligne d'échappement (4) dont est pourvu un moteur à combustion interne (1 ) d'un véhicule automobile, caractérisé en ce que le catalyseur trois voies (8) comprend un premier catalyseur trois voies élémentaire (8a) qui comporte un substrat métallique et un deuxième catalyseur trois voies élémentaire (8b) qui comporte un substrat céramique. A three-way catalyst (8) which is capable of carrying out three distinct reactions, including a reduction reaction of nitrogen oxides with nitrogen and carbon dioxide, an oxidation of carbon monoxide to carbon dioxide and an oxidation of hydrocarbons impregnated with carbon dioxide and water and which is intended to equip an exhaust line (4) which is provided with an internal combustion engine (1) of a motor vehicle, characterized in that the three-way catalyst (8 ) comprises a first elemental three-way catalyst (8a) which comprises a metal substrate and a second elemental three-way catalyst (8b) which comprises a ceramic substrate.
2. Catalyseur trois voies (8) selon la revendication précédente, caractérisé en ce que le premier catalyseur trois voies élémentaire (8a) et le deuxième catalyseur trois voies élémentaire (8b) sont logés à l'intérieur d'une enveloppe respective (1 1 a, 1 1 b). 2. Three-way catalytic converter (8) according to the preceding claim, characterized in that the first elemental three-way catalyst (8a) and the second elemental three-way catalyst (8b) are housed inside a respective shell (11). a, 1 1 b).
3. Catalyseur trois voies (8) selon la revendication 1 , caractérisé en ce que le premier catalyseur trois voies élémentaire (8a) et le deuxième catalyseur trois voies élémentaire (8b) sont logés à l'intérieur d'une enceinte commune (12). 3. Three-way catalytic converter (8) according to claim 1, characterized in that the first elemental three-way catalyst (8a) and the second elemental three-way catalyst (8b) are housed inside a common enclosure (12) .
4. Catalyseur trois voies (8) selon la revendication 1 , caractérisé en ce que le premier catalyseur trois voies élémentaire (8a) est exempt d'enveloppe. 4. Three-way catalyst (8) according to claim 1, characterized in that the first elemental three-way catalyst (8a) is shell-free.
5. Catalyseur trois voies (8) selon la revendication précédente, caractérisé en ce qu'il est raccordé directement à la ligne d'échappement. 5. Catalyst three-way (8) according to the preceding claim, characterized in that it is connected directly to the exhaust line.
6. Catalyseur trois voies (8) selon l'une quelconque des revendications précédentes, caractérisé en ce que le premier catalyseur trois voies élémentaire (8a) et le deuxième catalyseur trois voies élémentaire (8b) sont espacés l'un de l'autre d'une distance (D) non nulle. A three-way catalyst (8) according to any one of the preceding claims, characterized in that the first elemental three-way catalyst (8a) and the second elemental three-way catalyst (8b) are spaced apart from each other. a non-zero distance (D).
7. Catalyseur trois voies (8) selon l'une des revendications précédentes, caractérisé en ce que le volume du premier catalyseur (8a) et le volume du deuxième catalyseur (8b) sont définis selon la répartition suivante : - entre 15 et 35 % en volume pour le premier catalyseur (8a) , notamment au voisinage de 25%, et - entre 85 et 65% en volume pour le deuxième catalyseur (8b , notamment au voisinage de 75%. 7. Three-way catalyst (8) according to one of the preceding claims, characterized in that the volume of the first catalyst (8a) and the volume of the second catalyst (8b) are defined according to the following distribution: - between 15 and 35% by volume for the first catalyst (8a), especially in the vicinity of 25%, and - between 85 and 65% by volume for the second catalyst (8b, especially in the vicinity of 75%.
8. Ligne d'échappement (2) logeant un catalyseur trois voies (8) selon l'une quelconque des revendications précédentes. 8. Exhaust line (2) housing a three-way catalyst (8) according to any one of the preceding claims.
9. Moteur à combustion interne (1 ) équipé d'une ligne d'échappement (4) selon la revendication 8. 9. Internal combustion engine (1) equipped with an exhaust line (4) according to claim 8.
10. Véhicule automobile équipé d'un moteur à combustion interne (1 ) selon la revendication 9. 10. Motor vehicle equipped with an internal combustion engine (1) according to claim 9.
11. Véhicule automobile selon la revendication 10, caractérisé en ce que le véhicule automobile est équipé d'un moyen annexe de propulsion, notamment de type hybride moteur thermique/ machine électrique ou d'un système d'arrêt-démarrage. 11. Motor vehicle according to claim 10, characterized in that the motor vehicle is equipped with an auxiliary means of propulsion, in particular hybrid type heat engine / electrical machine or a stop-start system.
PCT/FR2015/050308 2014-03-04 2015-02-09 Three-way catalyst WO2015132491A1 (en)

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CN201580012100.9A CN106414929B (en) 2014-03-04 2015-02-09 Three-way catalyst and exhaust line, internal combustion engine and motor vehicles comprising it
EP15706900.6A EP3114330A1 (en) 2014-03-04 2015-02-09 Three-way catalyst

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FR1451728 2014-03-04
FR1451728A FR3018310B1 (en) 2014-03-04 2014-03-04 THREE-WAY CATALYST

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DE102019101576A1 (en) * 2019-01-23 2020-07-23 Dr. Ing. H.C. F. Porsche Aktiengesellschaft Device and method for exhaust gas aftertreatment of an internal combustion engine

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FR3018310B1 (en) 2020-07-31
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FR3018310A1 (en) 2015-09-11
CN106414929B (en) 2019-07-12

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