EP1769197A1 - Bougie de prechauffage et son procede de fabrication - Google Patents

Bougie de prechauffage et son procede de fabrication

Info

Publication number
EP1769197A1
EP1769197A1 EP05763780A EP05763780A EP1769197A1 EP 1769197 A1 EP1769197 A1 EP 1769197A1 EP 05763780 A EP05763780 A EP 05763780A EP 05763780 A EP05763780 A EP 05763780A EP 1769197 A1 EP1769197 A1 EP 1769197A1
Authority
EP
European Patent Office
Prior art keywords
conductive element
glow plug
electrically conductive
electrically
mosi
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.)
Ceased
Application number
EP05763780A
Other languages
German (de)
English (en)
Inventor
Mathias Herrmann
Hagen Klemm
Tassilo Moritz
Reinhard Lenk
Hans-Jürgen Richter
Andreas Göttler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Webasto SE
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 Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV, Webasto SE filed Critical Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung eV
Publication of EP1769197A1 publication Critical patent/EP1769197A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23Q—IGNITION; EXTINGUISHING-DEVICES
    • F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
    • F23Q7/001—Glowing plugs for internal-combustion engines
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/58085—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicides
    • C04B35/58092—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicides based on refractory metal silicides
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/141—Conductive ceramics, e.g. metal oxides, metal carbides, barium titanate, ferrites, zirconia, vitrous compounds
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C04B2235/3225—Yttrium oxide or oxide-forming salts thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/38—Non-oxide ceramic constituents or additives
    • C04B2235/3852—Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
    • C04B2235/3873—Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/38—Non-oxide ceramic constituents or additives
    • C04B2235/3891—Silicides, e.g. molybdenum disilicide, iron silicide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/602—Making the green bodies or pre-forms by moulding
    • C04B2235/6023—Gel casting
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/72—Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/75—Products with a concentration gradient
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/77—Density
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/80—Phases present in the sintered or melt-cast ceramic products other than the main phase
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23Q—IGNITION; EXTINGUISHING-DEVICES
    • F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
    • F23Q7/001—Glowing plugs for internal-combustion engines
    • F23Q2007/004—Manufacturing or assembling methods
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/027—Heaters specially adapted for glow plug igniters

Definitions

  • the invention relates to glow plugs and a method for producing such glow plugs.
  • the electrically conductive element essentially surrounds the electrically non-conductive element from two opposite sides and has an enlarged cross section in a distal region and a heating region which tapers in relation to the distal region in a proximal region.
  • the glow plugs according to the invention can preferably be used in auxiliary heaters operated with fuels, as are meanwhile installed in many motor vehicles.
  • Conductivity can be significantly increased and, in contrast, electrically insulating parts or sub-areas are produced or formed with relatively smaller proportions of MoSi 2 .
  • the glow plugs known from the prior art are also critical in many operating conditions, since they tend to oxidize due to the ceramic composite materials used, which has a disadvantageous effect on the service life and the achievable efficiency during use.
  • this object is achieved with glow plugs which have the features of claim 1. They can be produced by a method as defined in claim 12. Advantageous refinements and developments of the invention can be achieved with the features specified in the respective subordinate claims.
  • the glow plugs according to the invention with the two elements, each having a different electrical conductivity, made of a sintered ceramic composite material are designed such that a cross-sectional ratio of 2.5 to 5 to 1 for the distal region for the electrically conductive element, which has an enlarged cross-section compared to the cross-sectionally tapered proximal heating area and also the proximal heating area is covered to 60 to 85% of its surface by the material that forms the electrically non-conductive element.
  • the insulating layer covering the electrically conductive ceramic composite material should have an interface with a thickness> 100 ⁇ m.
  • the electrical line resistance of the distal region should be in the range between 10 and 40% in relation to the total electrical line resistance of an electrically conductive element.
  • MoSi 2 , Si 3 N 4 and at least one sintering additive can be used as starting materials for the respective ceramic composite materials, the ratio MoSi 2 to Si 3 N 4 in particular determining the electrical conductivity and accordingly increased proportions of MoSi 2 in the electrically conductive element, preferably at least 60% by mass should be included.
  • the proportion of MoSi 2 in the electrically non-conductive element should be in the range of approx. 40% by mass and possibly also less.
  • the glow plugs according to the invention are also to be used in elevated temperature ranges, sintering additives which are as refractory as possible should be used.
  • Rare earth oxides such as Y 2 0 3 are particularly preferred.
  • mixtures of rare earth oxides can also be used as sintering additives.
  • the powder mixtures used should be completely free of aluminum and aluminum oxide, whereby a minimum proportion ⁇ 1000 pp should be understood.
  • the molar ratio (Y 2 0 3 + R 2 0 3 ) / Si0 2 in the finished ceramic composite material should be ⁇ 0.55 to 1 in order to be able to maintain the desired high-temperature strength over an extended service life.
  • Elements and chemical compounds such as Mo, W, WC, Mo0 3 , Mo 5 Si 3 can also advantageously be added to the starting material composite. This also results in the possibility that MoSi 2 is formed reactively during the sintering, the reactively formed MoSi 2 component or WMoSi 2 component should be in the range between 0.5 to 10% by mass.
  • sintering necks can be formed during sintering, which advantageously influence the electrical conductivity.
  • a higher proportion of reactively formed MoSi 2 should, however, be avoided, since this leads to a deterioration in the reproducibility of the compression of the ceramic composite material during sintering.
  • the finished sintered ceramic composite material may also contain Mo 5 Si 3 , a proportion of Mo 5 Si 3 above 15% by mass, preferably above 10% by mass, being avoided.
  • the respective cross section of the proximal heating area tapered with respect to the distal area should be designed to be approximately evenly tapered in the two possible dimensions, which can be achieved, for example, with a rotationally symmetrical or approximately rotationally symmetrical cross section in this area.
  • An oxidation protection layer should advantageously also be formed on a glow plug according to the invention, this oxidation protection layer should at least cover the distal region of a glow plug. This reduces the fact that soot particles formed during operation are deposited on the electrically non-conductive part and can lead to a change in the electrical conductivity up to a short circuit, which in turn can have a negative influence on the regulation or control of the temperature at the proximal heating area.
  • Oxidation protection layers can be made, for example
  • oxidation protection layers can be formed with the aid of precursors, such as siloxanes or silanes, by glazing or reactive glazing. Furthermore, there is also the possibility of forming a relatively thin oxidation protection layer made of SiO 2 by converting MoSi 2 to SiO 2 which can be achieved as a result of oxidation.
  • the glow plugs according to the invention can be produced such that the two essential elements of the glow plugs are made from a powder mixture of the ceramic composite material, each with a suitable composition, in particular what the proportions of MoSi 2 and possibly additionally contained Mo 5 Si 3 contained in the powder mixtures with respect to relates to the respective proportion of Si 3 N 4 with which the desired electrical conductivity can essentially be influenced, used and subjected to a shaping to be carried out beforehand before the actual sintering process.
  • the electrically non-conductive element in an alternative there is the possibility of subjecting the electrically non-conductive element to a shaping by injection molding and thus producing it in a manner known from the prior art.
  • at least the electrically conductive element to be produced from a second suitable powder mixture is subjected to a colloidal shaping process and is molded onto the previously obtained shaped body for the non-electrically conductive element.
  • the procedure can also be such that the electrically non-conductive element is molded onto an electrically conductive element.
  • the organic components it contains and, if appropriate, also other volatile components, such as a liquid, are expelled.
  • the glow plugs are then finished by a conventional sintering process, which should preferably be carried out in a protective gas atmosphere.
  • both the molded body for the electrically conductive element and for the electrically non-conductive element are produced by a colloidal shaping process or the non-electrically conductive element, in particular also by injection molding, the molded bodies for non-electrically conductive elements should be subjected to a temperature exposure beforehand, in order to drive out at least the organic components before the shaping for the electrically conductive element is carried out.
  • colloidal shaping process for example gel casting, but also the so-called “coagulation casting processes”, such as temperature-influenced or induced shaping (TIF), come into question.
  • coagulation casting processes such as temperature-influenced or induced shaping (TIF)
  • the powdery starting materials namely the MoSi 2 , to which Mo 5 Si 3 has optionally been added, Si 3 N 4 and sintering additives in the form of rare earth oxides form a suspension which consists of a liquid, for example water or an organic solvent is formed, manufactured.
  • the suspension then contains other organic substances that can support the shaping.
  • the proportion of organic components is significantly reduced compared to the proportion required for shaping by injection molding.
  • the proportion of organic solvents should not be taken into account here.
  • the shaping with the gel casting method as described by O. Omatete, inter alia in "Gelcasting - a new ceramic forming process"; Am. Ceram. Soc. Bull.
  • the suspension can be filled into a shape having a negative contour of the electrically non-conductive element or else the glow plug contour.
  • the mold is polymerized within the mold
  • Monomer which leads to a partial solidification of the suspension.
  • the polymerization can be supported by heating, so that the required time can be shortened.
  • the mold used can have a dense, non-porous surface, so that penetration of parts of the suspension into the molding material can be avoided.
  • colloidal shaping can also be carried out by means of the direct coagulation molding method (direct coagulation casting: DCC), as described by TJ Graule, inter alia in "Casting uniform ceramics with direct coagulation”; CHEMTECH JUNE (1995) pages 31 to 37 and in EP 0 695 694 Bl or temperature-influenced shaping (TIF), as described by NS Bell in “Temperature Induced Forming”; Application of bridiging flucculation to near-ne shape production of ceramic parts "; Zeitschrift für Metallischen, 90 (1999) 6, pages 388 to 390 or described in DE 197 51 696 AI.
  • DCC direct coagulation casting
  • the required coagulation in the temperature-influenced shaping process can be achieved by increasing the temperature to approximately 65 ° C. to sufficiently solidify the molded body thus obtained.
  • the shaped body for the non-electrically conductive element has been produced in this form and the second electrically conductive element is to be molded on in a different shape or by removing additional elements from the previously used shape, the shaped body should be used for the non-electrically conductive element is kept at this temperature when the second suspension / dispersion with the increased MoSi 2 or MoSi 2 with Mo 5 Si 3 is filled into the interior of the mold.
  • shaping by means of gelatinization of gelatin can also be used with a reduction in temperature, as described, for example, by Y. Chen et al. in "Alumina Casting Based on gelation of Gelatine”; J. europ. Ceram. Soc. 19 (1999) pages 271 to 275.
  • a solidification for the formation of a sufficiently solid shaped body can also be achieved with the help of proteins or also by the gelation of starch with a corresponding temperature increase.
  • One way in which solidification with proteins can be achieved is known from EP 7 67 154 AI. Gelling using starch is described in EP 9 27 709 B1.
  • the solidification effect of a suspension with contained particles for the ceramic composite material can also be achieved by abolishing the effect of a dispersing aid by breaking it down or changing it by means of a chemical reaction in the suspension / dispersion. This is known for example from EP 0 905 107 A2.
  • TEZ temperature-influenced molding process
  • colloidal shaping processes already mentioned can be used in combination. It is thus possible to first carry out the molding for the non-electrically conductive element using one method and then to shape the molded body for the second electrically conductive element using a different shaping method.
  • the solids volume fraction contained in the respective suspensions should be coordinated with one another so that even shrinkage can be achieved during drying / sintering.
  • the molded body for the electrically non-conductive element has been obtained by injection molding
  • the molded body should be freed from organic components by debinding after the injection molding, before the molding of the molded body for the electrically conductive element is carried out using another molding process , is carried out by filling a mold with an appropriate suspension.
  • the open porosity that arises during debinding can be filled and sealed with the liquid that is used for the suspension of the electrically conductive element of the second component, so that it is ensured that the open porosity of the debindered, injection-molded molded body of the electrically non-conductive element does not absorb the liquid in the suspension of the electrically conductive component
  • porous forms which to a certain extent also absorb the respective liquid, such as can be prepared from plaster, for example.
  • the molded body prepared from the suspension is created and, after the body formation process known per se, the molded body obtained is left in a state of not yet dried with a sufficiently high green strength.
  • the molded part for the electrically conductive element can then be formed, for example, by gelcasting, by direct coagulation shaping method (DCC) or by another of the previously explained and described colloidal shaping methods.
  • the solid volume fractions in the two starting suspensions used for an electrically conductive and an electrically non-conductive ceramic composite material should be set so that defects, such as cracks due to different drying shrinkage, can be avoided. If possible, the same liquid volume fractions and the same volume should proportions of organic substances are observed.
  • the dried molded bodies which are joined together and have a sufficiently high green strength can then be sintered to form a finished glow plug. Before the actual sintering process, however, all organic components should have been removed by heat treatment.
  • mechanical post-processing can be carried out, in which, for example, a targeted shaping material removal is carried out.
  • contact elements for electrical contacting can be attached.
  • colloidal shaping processes to be used for at least one of the two elements of a glow plug require a significantly reduced proportion of organic compounds compared to the known injection molding technology
  • the proportion of organic components which is contained in total in a suspension / dispersion used for this should be ⁇ 10% by mass, based on the solids content.
  • Figure 1 shows an example of a glow plug according to the invention
  • Figure 2 shows an electrically conductive element for the example of Figure 1;
  • FIG. 3 shows an electrically non-conductive element for a glow plug according to FIG. 1;
  • Figure 4 is a nitrogen pressure temperature diagram during sintering
  • Figure 5 SEM micrographs of a sintered glow plug.
  • the glow plug shown in FIG. 1 is essentially formed from the two elements, namely the electrically non-conductive element 2 and the electrically conductive element 1, the latter element
  • the electrically conductive element 1 is molded onto the electrically non-conductive element 2.
  • the electrically conductive element 1 is designed such that it has a distal region 1.1 with an enlarged cross section, to which a proximal heating region 1.2 is connected.
  • the proximal heating region 1.2 has a cross section which is tapered, that is to say significantly reduced, in comparison with the distal region 1.1, which leads to an increase in the electrical line resistance in the proximal heating region 1.2. If the electrically conductive element 1 is now connected to an electrical voltage source, the proximal heating region 1.2 heats up during operation of the glow plug according to the invention.
  • a cross-sectional ratio on the electrically conductive element of 3.5 to 1 is maintained for the distal region 1.1 in relation to the proximal heating region 1.2 correspondingly tapered in cross-section.
  • FIG. 1 clearly shows that a surface area of 75% of the proximal heating area 1.2 is covered by the ceramic composite material of the electrically non-conductive element 2, so that the predominant part has been enclosed in the surface area of the proximal heating area 1.2.
  • the glow plug has a total length of 50 mm.
  • the proximal heating area 1.2 has a length of 16 mm in this example.
  • the cross section of the distal area 1.1 is 6 mm 2 and the cross section of the proximal heating area 1.2 is 2 mm 2 and is rotationally symmetrical.
  • a uniformly decreasing cross-sectional constriction is only provided in the transition area between the distal area 1.1 and the proximal heating area 1.2. Otherwise, no cross-sectional changes were made in the distal area 1.1 and in the proximal heating area 1.2.
  • the glow plug is symmetrical with respect to a plane that is aligned parallel to the longitudinal axis of the glow plug.
  • Polymerization started after about 20 minutes, and this could be accelerated by heating to a temperature of about 60 ° C.
  • the mold should be kept closed to prevent water from evaporating.
  • a sufficient green strength of the molded body could be achieved by the polymerization.
  • the plastic mold was opened and the plastic core was removed.
  • a second suspension for molding a molded body for the electrically conductive element 1 was then introduced.
  • This powder mixture was mixed with 11.4 g of acrylic acid amide, 0.95 of methylene diacrylic acid amide, 0.46 g of synthetic polyelectrolyte, alkali-free (from Dolapix CA, Zschimmer & Schwarz, DE) and 38.5 g of deionized water, which was added to a solution by means of NH 3 solution pH was adjusted to 10.5, processed into a suspension.
  • This suspension was filled into the mold containing the molded body for the electrically non-conductive element 2.
  • the composite element was removed from the mold and it had sufficient green strength and could be dried. Subsequently, the minor Proportion of organic substances expelled and there was a sintering, which could provide a finished glow plug.
  • the green solid composite element was sintered in a nitrogen atmosphere at a temperature of 1875 ° C., which was held for a period of 3 hours.
  • the nitrogen pressure was kept relatively low depending on the respective temperatures and increased successively until a closed porosity was reached and then the nitrogen pressure could be increased to approx. 50 bar in an isothermal sintering phase.
  • the nitrogen pressure can be increased to 2 bar and then further to 6 bar.
  • the nitrogen pressure can preferably be set as a function of the respective temperature, as illustrated in FIG. 4.
  • the electrically conductive element 1 had a specific electrical resistance of 1.8 ⁇ 10 "4 ⁇ cm and the electrically non-conductive element 2 had a specific resistance of 800 ⁇ cm.
  • the electrically conductive element 12.0 g Si 3 N 4 , 112.7 g MoSi 2 , 8.6 Y 2 0 3 , 10.5 g methacrylic acid amide, 0.8 g methylene diacrylic acid amide,
  • Example 1 0.46 g of synthetic polyelectrolyte and 34.0 g of deionized water (pH 10.5) were used to prepare a suspension. To this was added 4.5 g of a 5% aqueous ammonium peroxide sulfate solution and poured into a metal mold in order to achieve a polymerization leading to solidification, as in Example 1.
  • Example 2 Furthermore, the procedure was as described in Example 1 and the polymerization was initiated by adding 5% aqueous ammonium peroxide sulfate solution.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Resistance Heating (AREA)
  • Ceramic Products (AREA)

Abstract

L'invention concerne une bougie de préchauffage et son procédé de fabrication, bougie qui est fabriquée en un élément électro-conducteur et en un élément non électro-conducteur, un matériau composite céramique fritté étant utilisé pour la fabrication. De telles bougies de préchauffage peuvent être utilisées, de préférence, pour des chauffages autonomes de véhicules automobiles utilisant des carburants. L'invention a pour but d'avoir une fabrication souple et économique de telles bougies et d'obtenir en même temps une durée de vie et une résistance à l'oxydation accrues. A cet effet, l'invention est caractérisée en ce que l'élément conducteur est bordé, sur deux côtés opposés, par un élément non électro-conducteur, et en ce qu'il présente, dans la région distale, une section agrandie, tout en maintenant un rapport de section de 2,5 à 5 à 1, par rapport à la section de l'élément électro-conducteur. Le domaine de chauffage proximal de section amincie de l'élément électro-conducteur est recouvert à 60 à 85 % d'une surface du matériau de l'élément électro-conducteur.
EP05763780A 2004-06-11 2005-06-10 Bougie de prechauffage et son procede de fabrication Ceased EP1769197A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE102004029322 2004-06-11
DE102004033153A DE102004033153B4 (de) 2004-06-11 2004-06-29 Glühkerze und Verfahren zu ihrer Herstellung
PCT/DE2005/001079 WO2005121647A1 (fr) 2004-06-11 2005-06-10 Bougie de prechauffage et son procede de fabrication

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EP1769197A1 true EP1769197A1 (fr) 2007-04-04

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US (1) US20090212035A1 (fr)
EP (1) EP1769197A1 (fr)
JP (1) JP4815440B2 (fr)
CN (1) CN1973163B (fr)
DE (1) DE102004033153B4 (fr)
WO (1) WO2005121647A1 (fr)

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DE102011055283B4 (de) * 2011-11-11 2016-06-23 Borgwarner Ludwigsburg Gmbh Glühkerze und Verfahren zum Herstellen eines Glühstifts
CN102635479B (zh) * 2012-04-23 2014-06-04 常州联德电子有限公司 车用氮化硅陶瓷预热塞的制备方法
JP6573903B2 (ja) 2014-03-25 2019-09-11 ストラタシス リミテッド 層交差パターンを製作する方法及びシステム
EP3274172B1 (fr) * 2015-03-25 2023-04-26 Stratasys Ltd. Procédé et système de frittage in situ d'encre conductrice
ITUB20150793A1 (it) * 2015-05-22 2016-11-22 Nuovo Pignone Srl Materiale composito a base di siliciuro e processo per produrlo
DE102019217756A1 (de) * 2019-11-18 2021-05-20 Heraeus Noblelight Gmbh Glühkörper, dessen emissionsvolumen einen ohmschen widerstand in einem bereich hat und porös ist

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Also Published As

Publication number Publication date
DE102004033153A1 (de) 2006-02-09
CN1973163B (zh) 2011-02-16
US20090212035A1 (en) 2009-08-27
WO2005121647A1 (fr) 2005-12-22
CN1973163A (zh) 2007-05-30
JP4815440B2 (ja) 2011-11-16
DE102004033153B4 (de) 2007-03-29
JP2008501929A (ja) 2008-01-24

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