EP1466995A1 - Method of treating a valve comprising a nitruration step and valve obtained by this method - Google Patents
Method of treating a valve comprising a nitruration step and valve obtained by this method Download PDFInfo
- Publication number
- EP1466995A1 EP1466995A1 EP04300191A EP04300191A EP1466995A1 EP 1466995 A1 EP1466995 A1 EP 1466995A1 EP 04300191 A EP04300191 A EP 04300191A EP 04300191 A EP04300191 A EP 04300191A EP 1466995 A1 EP1466995 A1 EP 1466995A1
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- EP
- European Patent Office
- Prior art keywords
- valve
- valve seat
- nitriding
- finishing step
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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- 238000000034 method Methods 0.000 title claims abstract description 30
- 238000002485 combustion reaction Methods 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 11
- 150000004767 nitrides Chemical class 0.000 claims abstract description 8
- 230000002093 peripheral effect Effects 0.000 claims abstract description 3
- 238000005121 nitriding Methods 0.000 claims description 16
- 238000005299 abrasion Methods 0.000 claims description 6
- 239000000446 fuel Substances 0.000 claims description 6
- 238000003754 machining Methods 0.000 claims description 6
- 239000012764 mineral filler Substances 0.000 claims description 5
- 230000033001 locomotion Effects 0.000 claims description 4
- 238000003756 stirring Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 claims 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
- 208000035874 Excoriation Diseases 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 229910001347 Stellite Inorganic materials 0.000 description 4
- AHICWQREWHDHHF-UHFFFAOYSA-N chromium;cobalt;iron;manganese;methane;molybdenum;nickel;silicon;tungsten Chemical compound C.[Si].[Cr].[Mn].[Fe].[Co].[Ni].[Mo].[W] AHICWQREWHDHHF-UHFFFAOYSA-N 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 229910017052 cobalt Inorganic materials 0.000 description 3
- 239000010941 cobalt Substances 0.000 description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 3
- 239000003345 natural gas Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000001476 alcoholic effect Effects 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000003209 petroleum derivative Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/80—After-treatment
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
- F01L3/02—Selecting particular materials for valve-members or valve-seats; Valve-members or valve-seats composed of two or more materials
- F01L3/04—Coated valve members or valve-seats
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L2303/00—Manufacturing of components used in valve arrangements
Definitions
- the present invention relates to a method of manufacture of an internal combustion engine valve.
- the present invention relates more particularly to a method of treating a combustion engine valve internal having a nitriding step so as to form on it a peripheral layer of nitrided material.
- the sintered steel valve seats can be made with high levels of cobalt and molybdenum.
- the porosities of the valve seat can be impregnated with a lubricating material immiscible with the steel in the liquid state such as only lead.
- the valve seat can be shielded by a method of deposited by torch or "Plasma Transfer Arc".
- Types commonly used Stellite are: Stellite 12 (Cobalt base), Stellite grade F (Cobalt base) and Iron Stellite base.
- Valve seats can be hardened by treatment thermal when the valve head is made of steel martensitic.
- the object of the invention is therefore to limit wear more effectively. adhesive and abrasive between the valve seat and the scope of associated valve.
- the invention proposes a method of the type described previously, characterized in that the nitriding step is followed by a finishing step to improve the surface finish the valve at its seat against the valve seat, keeping a nitride layer of sufficient thickness to resist the combustion temperatures of the engine.
- the invention also proposes a motor valve with combustion which is obtained by the process according to one of preceding features, characterized in that the thickness of the layer of material treated by nitriding, at the level of range, after the finishing step, is greater than or equal to five micrometers.
- the cylinder head 10 has an exhaust duct 12 which allows to communicate the combustion chamber of the engine with the exhaust manifold (not shown) of the engine.
- the exhaust duct 12 is likely to be closed by an exhaust valve 14 which is guided axially in a valve guide 16 arranged in the cylinder head 10 of the engine.
- the valve 14 is mounted to move along its axis of displacement, which is here vertical.
- the valve 14 comprises a valve stem 18 and a valve head 20 which closes the exhaust duct 12 when the valve 14 is in its closed position.
- the valve head 20 has a bearing 22 substantially frustoconical which is intended to come in axial support against a complementary valve seat 24 arranged in the cylinder head 10, when the valve 14 is in its closed position.
- the seat 24 is here reported in the conduit exhaust 12.
- the general shape of the valve 14 is obtained by means of conventional manufacturing steps using, for example, forging and machining.
- the method of manufacturing the valve 14 comprises then steps that allow to give the valve 14 its definitive form, before mounting it in the engine.
- the process comprises a step known as nitriding process, during which the valve is treated with nitrogen enrichment.
- the nitriding step aims at increasing the hardness of the valve 14 and to minimize the coefficient of friction of the valve seat 22 on the valve seat 24.
- the superficial nitrogen in the material constituting the valve 14 a layer nitrided device, which includes a so-called combination and a so-called diffusion layer.
- the nitrided layer has a certain thickness, especially at the level of the valve 22.
- the thickness of the nitride layer at the level of valve seat 22 is, in the new state of the valve 14, from less than 5 micrometers.
- the minimal surface hardness of the Valve range is then 700 HV.
- the step nitriding is followed by a so-called finishing step aimed at improve the surface condition of the valve seat 22, retaining a nitride layer of sufficient thickness to minimize the coefficient of friction of the span 22 on the seat 24.
- the finishing step here consists of clipping the surface of the valve seat 22, in particular by removing the oxide peaks.
- the finishing step is carried out by a technique of surface treatment called tribofinition.
- a tribofinishing technique uses friction energy and vibration for the surface finish by abrasion, which allows obtaining profiles of very fine roughness.
- This abrasion treatment technique is implemented using a tribofinishing machine (not shown) to place the valve 14 in an enclosure with a mineral filler, such as friction cones or balls, The enclosure then undergoes a series of agitation movements of in order to achieve a superficial abrasion of the surface of the range of the valve 22 by the mineral filler.
- a tribofinishing machine not shown
- the finishing step is implemented so as to find a surface state of the valve seat 22 close to the state of surface of the part before nitriding.
- the finishing step can be performed using a conventional polishing technique such as the one used to improve the surface the valve stem 18.
- valve seat 22 in its state final is obtained directly after the finishing step, without need to resort to machining as in the process according to the state of the art.
- valve seat 22 cools by its contact with the valve seat 24.
- the process according to the invention makes it possible to increase the hardness surface of the valve seat 22 and to reduce its coefficient of friction against the valve seat 24.
- the manufacturing method according to the invention makes it possible to obtain a valve seat 22 whose nitrided layer has a minimum thickness of 5 micrometers.
- the process is carried out according to the invention so as to obtain a nitrided layer, at the level of the valve seat 22, of about 20 micrometers, which allows to further improve the hardness of the valve seat 22, and further decrease its coefficient of friction against the seat of valve 24.
- the method according to the invention also makes it possible to reduce 50% wear compared to the valves made according to the state of the technique.
- the invention makes it possible to guarantee good sealing and control the wear of the valve seat / valve seat contact, throughout the life of the engine.
- valve 14 obtained by the method according to the invention is particularly suitable for use in an engine running on fuel alcoholic, or with a fuel type LPG (Petroleum Gas Liquefied), or with a gaseous fuel such as CNG (Natural Gas Vehicle), CNG (Compressed Natural Gas), or GNA (Adsorbed Natural Gas).
- a fuel type LPG Petroleum Gas Liquefied
- a gaseous fuel such as CNG (Natural Gas Vehicle), CNG (Compressed Natural Gas), or GNA (Adsorbed Natural Gas).
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- General Engineering & Computer Science (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Description
La présente invention concerne un procédé de fabrication d'une soupape de moteur à combustion interne.The present invention relates to a method of manufacture of an internal combustion engine valve.
La présente invention concerne plus particulièrement un procédé de traitement d'une soupape de moteur à combustion interne comportant une étape de nitruration de manière à former sur celle-ci une couche périphérique de matériau nitrurée.The present invention relates more particularly to a method of treating a combustion engine valve internal having a nitriding step so as to form on it a peripheral layer of nitrided material.
Les déplacements de la soupape et sa venue en contact répétée, par sa portée, avec le siège de soupape associé, est susceptible de provoquer une usure rapide de la portée de soupape et du siège, en particulier lorsque le carburant utilisé dans le moteur est peu ou pas lubrifiant.The movements of the valve and its coming into contact repeated, by its range, with the associated valve seat, is likely to cause rapid wear of the range of valve and seat, especially when the fuel used in the engine is little or no lubricant.
On connaít déjà plusieurs solutions pour limiter cette usure.We already know several solutions to limit this wear.
On peut réaliser les sièges de soupape en acier fritté comportant un taux élevé de cobalt et de molybdène.The sintered steel valve seats can be made with high levels of cobalt and molybdenum.
On peut imprégner les porosités du siège de soupape avec un matériau lubrifiant non miscible avec l'acier à l'état liquide tel que du plomb.The porosities of the valve seat can be impregnated with a lubricating material immiscible with the steel in the liquid state such as only lead.
On peut blinder la portée de soupape par un procédé de stellitage déposé par torche ou "Plasma Transfert Arc". Les types de Stellite couramment employés sont les suivants : Stellite 12 (base Cobalt), Stellite grade F (base Cobalt) et Stellite base Fer.The valve seat can be shielded by a method of deposited by torch or "Plasma Transfer Arc". Types commonly used Stellite are: Stellite 12 (Cobalt base), Stellite grade F (Cobalt base) and Iron Stellite base.
On peut durcir les portées de soupape par traitement thermique lorsque la tête de soupape est réalisée en acier martensitique.Valve seats can be hardened by treatment thermal when the valve head is made of steel martensitic.
On peut aussi combiner les différentes solutions mentionnées ci-dessus.We can also combine the different solutions mentioned above.
Ces différentes solutions ne limitent pas l'usure de manière suffisamment efficace pour garantir la fiabilité de fonctionnement de la soupape pendant toute la durée de vie du moteur. These different solutions do not limit wear and tear sufficiently efficient to guarantee the reliability of operation of the valve throughout the life of the engine.
L'invention vise donc à limiter plus efficacement l'usure adhésive et abrasive entre le siège de soupape et la portée de soupape associée.The object of the invention is therefore to limit wear more effectively. adhesive and abrasive between the valve seat and the scope of associated valve.
Dans ce but, l'invention propose un procédé du type décrit précédemment, caractérisé en ce que l'étape de nitruration est suivie d'une étape de finition visant à améliorer l'état de surface de la soupape au niveau de sa portée contre le siège de soupape, en conservant une couche nitrurée d'épaisseur suffisante pour résister aux températures de combustion du moteur.For this purpose, the invention proposes a method of the type described previously, characterized in that the nitriding step is followed by a finishing step to improve the surface finish the valve at its seat against the valve seat, keeping a nitride layer of sufficient thickness to resist the combustion temperatures of the engine.
Selon d'autres caractéristiques de l'invention :
- l'étape de finition consiste à écrêter la surface de la portée de soupape, notamment en enlevant les pics d'oxyde ;
- l'étape de finition est réalisée par une technique dite de tribofinition, au cours de laquelle la soupape est placée dans une enceinte avec une charge minérale, l'enceinte subissant une série de mouvements d'agitation de manière à réaliser une abrasion superficielle de la surface de la portée de soupape par la charge minérale ;
- la portée de soupape dans son état final est obtenue directement après l'étape de finition, sans recourir à un usinage ;
- the finishing step consists in clipping the surface of the valve seat, in particular by removing the oxide peaks;
- the finishing step is carried out by a technique known as tribofinishing, during which the valve is placed in a chamber with a mineral filler, the enclosure undergoing a series of stirring movements so as to achieve a superficial abrasion of the surface of the valve seat by the mineral charge;
- the valve seat in its final state is obtained directly after the finishing step, without resorting to machining;
L'invention propose aussi une soupape de moteur à combustion qui est obtenu par le procédé selon l'une des caractéristiques précédentes, caractérisé en ce que l'épaisseur de la couche de matériau traitée par nitruration, au niveau de la portée, après l'étape de finition, est supérieure ou égale à cinq micromètres.The invention also proposes a motor valve with combustion which is obtained by the process according to one of preceding features, characterized in that the thickness of the layer of material treated by nitriding, at the level of range, after the finishing step, is greater than or equal to five micrometers.
Selon d'autres caractéristiques de la soupape :
- l'épaisseur totale de la couche de matériau traitée par nitruration est sensiblement égale à vingt micromètres.
- la soupape est utilisée dans un moteur prévu pour fonctionner avec un carburant gazeux.
- the total thickness of the layer of material treated by nitriding is substantially equal to twenty microns.
- the valve is used in an engine intended to operate with a gaseous fuel.
D'autres caractéristiques et avantages de l'invention apparaítront à la lecture de la description détaillée qui suit pour la compréhension de laquelle on se reportera à la figure unique qui représente une soupape d'échappement de moteur à combustion interne.Other features and advantages of the invention will appear on reading the following detailed description for the understanding of which we will refer to the single figure that represents a combustion engine exhaust valve internal.
On a représenté sur la figure unique une portion de
culasse 10 de moteur à combustion interne.There is shown in the single figure a portion of
La culasse 10 comporte un conduit d'échappement 12 qui
permet de faire communiquer la chambre de combustion du
moteur avec le collecteur d'échappement (non représenté) du
moteur.The
Le conduit d'échappement 12 est susceptible d'être obturé
par une soupape d'échappement 14 qui est guidée axialement
dans un guide de soupape 16 agencé dans la culasse 10 du
moteur.The
La soupape 14 est montée mobile suivant son axe de déplacement, qui est ici vertical.The valve 14 is mounted to move along its axis of displacement, which is here vertical.
La soupape 14 comporte une tige de soupape 18 et une
tête de soupape 20 qui obture le conduit d'échappement 12
lorsque la soupape 14 occupe sa position fermée.The valve 14 comprises a
La tête de soupape 20 comporte une portée 22
sensiblement tronconique qui est prévue pour venir en appui axial
contre un siège de soupape 24 complémentaire agencé dans la
culasse 10, lorsque la soupape 14 occupe sa position fermée.The
Le siège 24 est ici rapporté dans le conduit
d'échappement 12.The
Bien entendu, l'invention s'applique aussi bien à une soupape d'admission qu'à la soupape d'échappement 14.Of course, the invention applies equally well to a intake valve at the exhaust valve 14.
On décrira maintenant le procédé de fabrication de la soupape 14, conformément aux enseignements de l'invention.We will now describe the manufacturing process of the valve 14, according to the teachings of the invention.
La forme générale de la soupape 14 est obtenue par des étapes classiques de fabrication faisant appel, par exemple, au forgeage et à l'usinage.The general shape of the valve 14 is obtained by means of conventional manufacturing steps using, for example, forging and machining.
Le procédé de fabrication de la soupape 14 comporte ensuite des étapes qui permettent de donner à la soupape 14 sa forme définitive, avant son montage dans le moteur. The method of manufacturing the valve 14 comprises then steps that allow to give the valve 14 its definitive form, before mounting it in the engine.
De manière classique, le procédé comporte une étape dite de nitruration, au cours de laquelle la soupape est traitée par enrichissement en azote.In a conventional manner, the process comprises a step known as nitriding process, during which the valve is treated with nitrogen enrichment.
L'étape de nitruration vise à augmenter la dureté de la
soupape 14 et à minimiser le coefficient de frottement de la
portée de soupape 22 sur le siège de soupape 24.The nitriding step aims at increasing the hardness of the
valve 14 and to minimize the coefficient of friction of the
Au cours de la nitruration, l'apport superficiel d'azote
forme, dans le matériau constituant la soupape 14, une couche
périphérique nitrurée, qui comporte une couche dite de
combinaison et une couche dite de diffusion. La couche nitrurée a
une épaisseur déterminée, en particulier au niveau de la portée
de soupape 22.During nitriding, the superficial nitrogen
in the material constituting the valve 14, a layer
nitrided device, which includes a so-called
combination and a so-called diffusion layer. The nitrided layer has
a certain thickness, especially at the level of the
Pour que le traitement de nitruration soit efficace, il est
nécessaire que l'épaisseur de la couche nitrurée au niveau de la
portée de soupape 22 soit, à l'état neuf de la soupape 14, d'au
moins 5 micromètres. La dureté superficielle minimale de la
portée de soupape est alors de 700 HV.In order for the nitriding treatment to be effective, it is
necessary that the thickness of the nitride layer at the level of
Conformément aux enseignements de l'invention, l'étape
de nitruration est suivie d'une étape dite de finition visant à
améliorer l'état de surface de la portée de soupape 22, en
conservant une couche nitrurée d'épaisseur suffisante pour
minimiser le coefficient de frottement de la portée 22 sur le
siège 24.In accordance with the teachings of the invention, the step
nitriding is followed by a so-called finishing step aimed at
improve the surface condition of the
L'étape de finition consiste ici à écrêter la surface de la
portée de soupape 22, notamment en enlevant les pics d'oxyde.The finishing step here consists of clipping the surface of the
De préférence, l'étape de finition est réalisée par une technique de traitement de surface dite de tribofinition.Preferably, the finishing step is carried out by a technique of surface treatment called tribofinition.
Une technique de tribofinition utilise l'énergie du frottement et de la vibration pour le fini de surface par abrasion, ce qui permet l'obtention de profils de rugosité très fine.A tribofinishing technique uses friction energy and vibration for the surface finish by abrasion, which allows obtaining profiles of very fine roughness.
Cette technique de traitement par abrasion est mise en
oeuvre à l'aide d'une machine de tribofinition (non représentée)
permettant de placer la soupape 14 dans une enceinte avec une
charge minérale, telle que des cônes de frictions ou des billes,
L'enceinte subit alors une série de mouvements d'agitation de
manière à réaliser une abrasion superficielle de la surface de la
portée de la soupape 22 par la charge minérale.This abrasion treatment technique is implemented
using a tribofinishing machine (not shown)
to place the valve 14 in an enclosure with a
mineral filler, such as friction cones or balls,
The enclosure then undergoes a series of agitation movements of
in order to achieve a superficial abrasion of the surface of the
range of the
L'étape de finition est mise en oeuvre de manière retrouver
un état de surface de la portée de soupape 22 proche de l'état de
surface de la pièce avant nitruration.The finishing step is implemented so as to find
a surface state of the
Selon une variante de réalisation, l'étape de finition peut
être réalisée au moyen d'une technique de polissage classique
telle que celle qui est utilisée pour améliorer l'état de surface de
la tige de soupape 18.According to an alternative embodiment, the finishing step can
be performed using a conventional polishing technique
such as the one used to improve the surface
the
La finition par tribofinition présente l'avantage d'être indépendante de la géométrie de la pièce, ce qui faciliter sa mise en oeuvre dans le cas de la soupape 14.The finishing by tribofinition has the advantage of being independent of the geometry of the part, which facilitates its implementation implemented in the case of the valve 14.
Avantageusement, la portée de soupape 22 dans son état
final est obtenue directement après l'étape de finition, sans qu'il
ne soit nécessaire de recourir à un usinage comme dans le
procédé selon l'état de la technique.Advantageously, the
Il n'est donc pas nécessaire de rectifier les portées de
soupape 22 par usinage après la nitruration, ce qui permet de
conserver une couche nitrurée d'épaisseur suffisante pour
minimiser le coefficient de frottement de la portée 22 sur son
siège 24.It is therefore not necessary to rectify the
Bien que la portée 22, en particulier la portée 22 de la
soupape d'échappement 14, soit soumise aux très hautes
températures atteintes par les gaz de combustion, on constate
que la couche nitrurée de la portée de soupape 22 ne s'altère
pas. En effet, malgré une température à coeur de la soupape 14
très élevée, la portée de soupape 22 se refroidit par son contact
avec le siège de soupape 24.Although the
Le procédé selon l'invention permet d'augmenter la dureté
superficielle de la portée de soupape 22 et de diminuer son
coefficient de frottement contre le siège de soupape 24.The process according to the invention makes it possible to increase the hardness
surface of the
Ces caractéristiques sont obtenues grâce à la conservation d'une couche nitrurée d'épaisseur minimale, alors qu'auparavant, dans le procédé selon l'état de la technique, l'étape d'usinage effectuée après la nitruration retirait la majorité de l'épaisseur de matériau nitrurée.These features are achieved through conservation a nitride layer of minimal thickness, whereas before, in the method according to the state of the art, the machining step performed after nitriding removed the majority of the thickness of nitrided material.
Le procédé de fabrication selon l'invention permet d'obtenir
une portée de soupape 22 dont la couche nitrurée a une
épaisseur minimale de 5 micromètres.The manufacturing method according to the invention makes it possible to obtain
a
De préférence, on met en oeuvre le procédé selon
l'invention de manière à obtenir une couche nitrurée, au niveau de
la portée de soupape 22, d'environ 20 micromètres, ce qui permet
d'améliorer encore la dureté de la portée de soupape 22, et de
diminuer encore son coefficient de frottement contre le siège de
soupape 24.Preferably, the process is carried out according to
the invention so as to obtain a nitrided layer, at the level of
the
Le procédé selon l'invention permet aussi de réduire l'usure de 50% par rapport aux soupapes réalisées selon l'état de la technique.The method according to the invention also makes it possible to reduce 50% wear compared to the valves made according to the state of the technique.
On note que le procédé selon l'invention est combinable avec les solutions connues pour limiter l'usure du contact siège de soupape/portée de soupape.It is noted that the method according to the invention is combinable with the known solutions to limit the wear of the seat contact valve / valve seat.
L'invention permet de garantir la bonne étanchéité et de maítriser l'usure du contact siège de soupape/portée de soupape, pendant toute la durée de vie du moteur.The invention makes it possible to guarantee good sealing and control the wear of the valve seat / valve seat contact, throughout the life of the engine.
Grâce à ces caractéristiques, la soupape 14 obtenue par le procédé selon l'invention est particulièrement adaptée à une utilisation dans un moteur fonctionnant avec un carburant alcoolisé, ou avec un carburant de type GPL (Gaz de Pétrole Liquéfié), ou encore avec un carburant gazeux tel que du GNV (Gaz Naturel Véhicule), du GNC (Gaz Naturel Compressé), ou du GNA (Gaz Naturel Adsorbé).Thanks to these characteristics, the valve 14 obtained by the method according to the invention is particularly suitable for use in an engine running on fuel alcoholic, or with a fuel type LPG (Petroleum Gas Liquefied), or with a gaseous fuel such as CNG (Natural Gas Vehicle), CNG (Compressed Natural Gas), or GNA (Adsorbed Natural Gas).
Claims (7)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR0304507 | 2003-04-11 | ||
| FR0304507A FR2853669B1 (en) | 2003-04-11 | 2003-04-11 | PROCESS FOR PROCESSING A VALVE COMPRISING A NITRIDATION STEP AND VALVE OBTAINED BY THE PROCESS |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP1466995A1 true EP1466995A1 (en) | 2004-10-13 |
| EP1466995B1 EP1466995B1 (en) | 2012-07-18 |
Family
ID=32865410
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP04300191A Expired - Lifetime EP1466995B1 (en) | 2003-04-11 | 2004-04-08 | Method of treating a valve comprising a nitruration step and valve obtained by this method |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP1466995B1 (en) |
| FR (1) | FR2853669B1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0738786A1 (en) * | 1995-04-21 | 1996-10-23 | Fuji Oozx Inc. | Method of treating the surface of a poppet valve |
| EP0937866A2 (en) * | 1998-02-20 | 1999-08-25 | Eaton Corporation | Engine valve assembly |
| WO2002025068A1 (en) * | 2000-09-21 | 2002-03-28 | Nissan Motor Co., Ltd. | Sliding member and method of manufacturing thereof |
-
2003
- 2003-04-11 FR FR0304507A patent/FR2853669B1/en not_active Expired - Fee Related
-
2004
- 2004-04-08 EP EP04300191A patent/EP1466995B1/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0738786A1 (en) * | 1995-04-21 | 1996-10-23 | Fuji Oozx Inc. | Method of treating the surface of a poppet valve |
| EP0937866A2 (en) * | 1998-02-20 | 1999-08-25 | Eaton Corporation | Engine valve assembly |
| WO2002025068A1 (en) * | 2000-09-21 | 2002-03-28 | Nissan Motor Co., Ltd. | Sliding member and method of manufacturing thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| EP1466995B1 (en) | 2012-07-18 |
| FR2853669B1 (en) | 2006-12-08 |
| FR2853669A1 (en) | 2004-10-15 |
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