GB2238349A - Ceramic faced i.c. engine valves - Google Patents

Ceramic faced i.c. engine valves Download PDF

Info

Publication number
GB2238349A
GB2238349A GB8926705A GB8926705A GB2238349A GB 2238349 A GB2238349 A GB 2238349A GB 8926705 A GB8926705 A GB 8926705A GB 8926705 A GB8926705 A GB 8926705A GB 2238349 A GB2238349 A GB 2238349A
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GB
United Kingdom
Prior art keywords
layer
ceramic
ceramic material
valve
valve according
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
Application number
GB8926705A
Other versions
GB8926705D0 (en
GB2238349B (en
Inventor
Duncan Robert Bury
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.)
Federal Mogul Technology Ltd
Original Assignee
T&N Technology Ltd
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 T&N Technology Ltd filed Critical T&N Technology Ltd
Priority to GB8926705A priority Critical patent/GB2238349B/en
Publication of GB8926705D0 publication Critical patent/GB8926705D0/en
Publication of GB2238349A publication Critical patent/GB2238349A/en
Application granted granted Critical
Publication of GB2238349B publication Critical patent/GB2238349B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • 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
    • 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
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Coating By Spraying Or Casting (AREA)

Abstract

The valve face 14 is coated with a layer 18 of a ceramic material with an overlying layer 20 of a metallic material, the ceramic material serving as an insulation medium and the metallic material serving to protect the ceramic layer from the ingression of waste products from the combustion mixture which reduce the insulation properties of the ceramic. The layers may be plasma sprayed with the ceramic being 8% yttria-stabilized zirconia and the metallic material Ni, NiCrAlY, CoCrAlY or FeCrAlY. The face coating may be graded from 100% metallic to 100% ceramic to 100% metallic outermost. The layers may be located within a recess (22, Figs. 3 and 4) in the valve head and the outermost metallic layer may extend over the recess rim. <IMAGE>

Description

Ceramic coated engine valves This invention relates to valves for use in internal combustion engines and particularly to poppet valves having a thermal insulation coating on the face within the combustion chamber.
A problem associated with internal combustion engines and especially with diesel engines is loss of heat from the combustion chamber through the valves which in turn become too hot. It is desirable to lower the operating temperature of the valve; this is best achieved by insulating the valve to prevent it from absorbing as much heat from the combustion chamber.This also reduces heat loss from the combustion chamber thereby leading to an increase in thermodynamic temperature of the combustion chamber which may reduce the levels of undesirable emissions from the engine, whilst leading to smaller cooling systems and hence more efficient engines.
One method of insulating the poppet valves is to coat the face of the valve which is within the combustion chamber with a layer of a ceramic material. The use of ceramic coatings to insulate engine components in this way is well known.
A problem which arises when coating the valve face in this manner is the ingression of combustion products into the porosity of the sprayed ceramic material. Such combustion products may chemically attack the valve and/or ceramic layer and may reduce the insulation and thermal shock resistance properties of the ceramic layer by filling the porosity of the ceramic material. Also, secondary explosions ("knocking") may occur owing to wet fuel entering the pores of the hot ceramic material.
It is known to treat ceramic-coated engine components such as cylinder liners, etc, with porosity fillers in order to prevent the ingression of undesirable materials into the porosity of the ceramic layer. The MONITOR" (trade mark) treatment of Monitor Coatings Limited uses chromium-based materials as a porosity filler; however, this treatment reduces the insulation and thermal shock resistance properties of the ceramic layer by filling the porosity through the sprayed layer.
It is an object of the present invention to produce an insulated valve for use in an internal combustion engine which does not suffer from the problems caused by the ingression of combustion products or from a reduction in the porosity level of the ceramic material.
According to the present invention there is provided a valve for use in an internal combustion engine characterised in that the valve face has a coating of a layer of a ceramic material on top of which is a coating of a layer of a metallic material.
The ceramic material used is preferably zirconia-based and is more preferably partially stabilised zirconia.
The material used for the metallic coating must exhibit resistance to high temperature degradation in a corrosive environment and desirably, should also have a low heat capacity and high thermal conductivity. The material used should also form a good bond with the ceramic material and/or the valve face material.
Suitable materials for the purpose of this invention include NiCrAlY, CoCrAlY, FeCrAlY or Ni.
The use of such metallic materials to cover the ceramic layer serves to prevent the ingression of combustion products into the pores of the ceramic material without materially affecting the insulating properties of said ceramic material.
In a first preferred embodiment of the invention the valve face is coated with firstly a suitable bond coat on top of which is a graded layer comprising a metallic material and a ceramic material the proportions of which alter inversely such that immediately adjacent to the bond coat the graded layer contains 100% metallic material and 0% ceramic material whilst at the top of the graded layer, furthest away from the bond coat, the graded layer contains 0% metallic material and 100% ceramic material; on top of the graded layer is a further layer comprising 100% ceramic material which in turn is coated with a second graded layer comprising metallic material and ceramic material in inversely altering proportions such that immediately adjacent to the ceramic layer the graded layer comprises 0% metallic material and 100% ceramic material whilst at the top of the second graded layer, furthest away from the ceramic layer, the graded layer comprises 100% metallic material and 0% ceramic material; on top of the second graded layer is a final layer comprising 100 metallic material.
The graded layers are applied to a thickness in the range 0.05mm to 0.25mm and more preferably in the range O.lmm to 0.2mm.
In a second embodiment of the invention the valve face has a recess which contains the ceramic material and where the overlying metallic layer is flush with the annular rim formed on the valve face.
An advantage to be gained from this embodiment is that the edges of the ceramic layer are especially prone to attack.
By confining the ceramic layer within the recess in this manner the edges of the layer are less vulnerable to attack In a third embodiment of the invention the valve face has a recess which contains the layer of ceramic material and where the overlying metallic material extends out of the recess to cover the annular rim formed on the valve face.
In a fourth embodiment of the present invention the valve face has a recess which is filled with an insulating and protective layer as described in the first preferred embodiment of the invention.
A valve may comprise more than one of the preferred features described above.
The edge of the recess may be chamfered with an angle in the range of 25 degrees to 75 degrees and preferably in the range of 30 degrees to 60 degrees.
In all embodiments of the invention, the ceramic material is applied to a thickness in the range 0.5mm to 2.Omm and more preferably in the range l.Omm to 1.5mm.
The overlying metallic material may be applied to a maximum thickness at any point on the valve face, of up to 1 .Omm.
The invention will now be more fully described by way of illustration only with reference to the following Examples and accompanying drawings of which: Figure 1 shows a section through a valve according to the present invention; Figures 2 and 2a show a section through a first alternative embodiment and the fine detail thereof respectively, of a valve according to the present invention; Figure 3 shows a section through a second alternative embodiment of a valve according to the present invention.
Figure 4 shows a section through a third alternative embodiment of a valve according to the present invention.
Referring now to the drawings and where the same features are denoted by common reference numbers:- Figure 1 shows a poppet valve indicated generally at 10 having a head 12 with a face 14 lying within a combustion chamber (not shown).The face 14 has a coating of a layer 16 of a suitable metallic bond coat which in turn has a coating of a layer 18 of a ceramic material. On top of the ceramic layer lies a layer 20 of a metallic material.
Figures 2 and 2a show a poppet valve, substantially as shown in Figure 1, and the fine detail of the face 14 of the valve respectively. The face 14 has a multi-layer coating 30 comprising a layer 16 of a suitable metallic bond coat on top of which is a graded layer 32 containing codeposited metallic and ceramic material, the proportions of which vary inversely such that at the boundary with the bond coat layer the graded layer contains 100% metallic material: 0% ceramic material and at the top of the graded layer the composition is reversed, 0% metallic:100% ceramic.The graded layer is in turn covered with a layer 18 of ceramic material which is itself covered with a further graded layer 34 again containing metallic and ceramic materials in inversely varying proportions such that at the boundary with the ceramic layer 18 the second graded layer contains 0% metallic:100% ceramic whilst at the top of the graded layer it contains 100% metallic:0% ceramic. The second graded layer is coated with a final layer 20 of a metallic material.
Figure 3 shows a poppet valve, substantially as shown in Figure 1, wherein the face 14 has a recess 22 which contains a layer 16 of a suitable metallic bond coat on top of which is a layer 18 of a ceramic material over which lies a layer 20 of a metallic material which completely fills the recess such that the surface of the metallic layer is flush with the annular rim 24, formed on the valve face.
Figure 4 shows a poppet valve sustantially as shown in Figures 1 & 3, wherein the layer 20 of a metallic material fills the recess 22 and extends out of the recess to cover the annular rim 24 formed on the valve face.
Example 1 A poppet valve for use in an internal combustion engine was selected. The combustion face of the valve was roughened by a process of wet grit blasting to minimise retained grit. The roughened surface was then coated with a layer of AMDRY 995 (trade mark) NiCrAlY bond coat, to a depth of 0.025mm, by plasma spraying. A layer of ceramic material comprising 8% yttria-stabilised zirconia was then sprayed onto the bond coat layer to a thickness of l.Omm using a plasma spraying unit. Finally, a layer of a metallic material comprising AMDRY 995 NiCrAlY was plasma sprayed onto the 'as-sprayed' ceramic layer to a thickness of O.lmm.
Example 2 A poppet valve as used in Example 1 was selected and a recess machined into its combustion face to a depth of 1.125mm and to 1.0mum from the edge of the valve face, the edge of the recess being chamfered to an angle of 45 degrees. The valve face was masked to protect the annular rim so formed and the recess was then roughened by wet grit blasting. The recess was then coated with layers of AMDRY 995 NiCrAlY, 8% yttria-stablisied zirconia and a further layer of AMDRY 995 as in Example 1 such that the recess was completely filled and the final NiCrAlY layer was flush with the annular rim.
Example 3 A poppet valve as used in Example I was selected and its combustion face was roughened by wet grit blasting. The roughened surface was then coated with a layer of AMDRY 995 NiCrAlY bond coat to a depth of 0.025mm by plasma spraying. AMDRY 995 NiCrAlY was then codeposited, by plasma spraying, with ceramic material comprising 8% yttria-stabilised zirconia on top of the bond coat to a depth of 0.15mm, the proportions of ceramic material and NiCrAlY altering inversely such that the graded layer produced contained 100% NiCrAlY:0% ceramic immediately adjacent to the bond coat layer and 0% NiCrAlY:100% ceramic at the top of the graded layer, furthest away from the bond coat. A layer of the ceramic material was then applied on top of the graded layer to a depth of lmm, over which was applied a further codeposited layer, to a depth of 0.15 mm, comprising NiCrAlY and the ceramic material.
The proportions of NiCrAlY to ceramic material in this second graded layer again varied, from 0% NiCrAlY:100% ceramic to 100% NiCrAlY:0% ceramic. Finally, a layer of NiCrAlY 0.025mm deep was applied on top of the second graded layer.

Claims (15)

1. A valve for use in an internal combustion engine wherein the valve face has a coating of a layer of a ceramic material on top of which is a coating of a layer of a metallic material.
2. A valve according to claim 1 wherein the ceramic material is zirconia-based.
3. A valve according to claim 2 wherein the ceramic material is partially stabilised zirconia.
4. A valve according to any one of claims 1, 2 or 3 wherein the metallic material is selected from NiCrAlY, CoCrAlY, FeCrAlY or Ni.
5. A valve according to any one preceding claim wherein the valve face is coated with firstly a suitable bond coat on top of which is a graded layer comprising a metallic material and a ceramic material the proportions of which alter inversely such that immediately adjacent to the bond coat the graded layer contains 100% metallic material and 0% ceramic material whilst at the top of the graded layer, furthest away from the bond coat, the graded layer contains 0% metallic material and 100% ceramic material; on top of the graded layer is a further layer comprising 100% ceramic material which in turn is coated with a second graded layer comprising metallic material and ceramic material in inversely altering proportions such that immediately adjacent to the ceramic layer the graded layer comprises 0% metallic material and 100% ceramic material whilst at the top of the second graded layer, furthest away from the ceramic layer, the graded layer comprises 100% metallic material and 0% ceramic material; on top of the second graded layer is a final layer comprising 100% metallic material.
6. A valve according to claim 5 wherein the graded layers are applied to a thickness in the range 0.05mm to 0.25mm.
7. A valve according to claim 6 wherein the graded layers are applied to a thickness in the range O.lmm to 0.2mm.
8. A valve according to any one preceding claim wherein the valve face has a recess which contains the ceramic material and where the overlying metallic material is flush with the annular rim of the valve face.
9. A valve according to claim 8 wherein the metallic material extends out of the recess to cover the annular rim of the valve face.
10. A valve according to claims 8 or 9 wherein the edge of the recess is preferably chamfered at an angle in the range of 25 degrees to 75 degrees.
11. A valve according to claim 10 wherein the edge of the recess is preferably chamfered at an angle in the range of 30 degrees to 60 degrees.
12. A valve according to any one preceding claim wherein the ceramic material is applied to a thickness in the range 0.5mm to 2.Omm.
13. A valve according to claim 12 wherein the ceramic material is applied to a thickness in the range l.Omm to 1.5mm.
14. A valve according to any one preceding claim wherein the metallic material is applied to a maximum thickness of up to l.Omm.
15. A valve substantially as hereinbefore described with reference to the accompanying specification and to Examples 1, 2 or 3 thereof and to Figures 1, 2, 2a, 3 or 4 of the accompanying drawings.
GB8926705A 1989-11-25 1989-11-25 Ceramic coated engine valves. Expired - Fee Related GB2238349B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8926705A GB2238349B (en) 1989-11-25 1989-11-25 Ceramic coated engine valves.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8926705A GB2238349B (en) 1989-11-25 1989-11-25 Ceramic coated engine valves.

Publications (3)

Publication Number Publication Date
GB8926705D0 GB8926705D0 (en) 1990-01-17
GB2238349A true GB2238349A (en) 1991-05-29
GB2238349B GB2238349B (en) 1993-09-15

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GB8926705A Expired - Fee Related GB2238349B (en) 1989-11-25 1989-11-25 Ceramic coated engine valves.

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2341891A (en) * 1998-09-23 2000-03-29 Rover Group A poppet valve for an internal combustion engine having a protuberance on its valve head
WO2002044082A2 (en) * 2000-11-30 2002-06-06 Ballard Power Systems Inc. Compact multiple tube steam reformer
GB2380492A (en) * 2001-09-05 2003-04-09 Trw Ltd Friction member with graded coating
WO2006092516A1 (en) * 2005-03-03 2006-09-08 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Method of coating a pipe element or device used to convey gaseous oxygen
GB2443283A (en) * 2006-10-26 2008-04-30 Gen Electric Rub coating for gas turbine engine compressors
CN103867248A (en) * 2012-12-11 2014-06-18 瓦锡兰瑞士公司 Gas exchange valve and method for producing a gas exchange valve
EP3106634A4 (en) * 2014-02-12 2017-11-29 Nittan Valve Co., Ltd. Poppet valve
EP2413107B1 (en) * 2010-07-26 2020-04-08 Krohne AG Magnetic-inductive flow measuring apparatus
WO2022133467A1 (en) * 2020-12-17 2022-06-23 Cummins Inc. Combustion cylinder end face components including thermal barrier coatings

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112725720B (en) * 2020-12-23 2022-08-09 中国兵器工业第五九研究所 High-temperature-resistant composite ceramic insulating coating and preparation method thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0049396A1 (en) * 1980-10-03 1982-04-14 Eaton Corporation Poppet valve shield
EP0051300A1 (en) * 1980-10-31 1982-05-12 Nippon Kokan Kabushiki Kaisha Method for making an exhaust valve for a Diesel engine
EP0194701A1 (en) * 1985-03-14 1986-09-17 H.C. Starck GmbH & Co. KG Process for the production of protective surface layers
EP0217991A1 (en) * 1985-10-04 1987-04-15 Repco Limited Ceramic material coatings

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0049396A1 (en) * 1980-10-03 1982-04-14 Eaton Corporation Poppet valve shield
EP0051300A1 (en) * 1980-10-31 1982-05-12 Nippon Kokan Kabushiki Kaisha Method for making an exhaust valve for a Diesel engine
EP0194701A1 (en) * 1985-03-14 1986-09-17 H.C. Starck GmbH & Co. KG Process for the production of protective surface layers
EP0217991A1 (en) * 1985-10-04 1987-04-15 Repco Limited Ceramic material coatings

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2341891A (en) * 1998-09-23 2000-03-29 Rover Group A poppet valve for an internal combustion engine having a protuberance on its valve head
WO2002044082A2 (en) * 2000-11-30 2002-06-06 Ballard Power Systems Inc. Compact multiple tube steam reformer
WO2002044082A3 (en) * 2000-11-30 2002-10-10 Ballard Power Systems Compact multiple tube steam reformer
US6759016B2 (en) 2000-11-30 2004-07-06 Ballard Power Systems Inc. Compact multiple tube steam reformer
GB2380492A (en) * 2001-09-05 2003-04-09 Trw Ltd Friction member with graded coating
JP4838269B2 (en) * 2005-03-03 2011-12-14 レール・リキード−ソシエテ・アノニム・プール・レテュード・エ・レクスプロワタシオン・デ・プロセデ・ジョルジュ・クロード Method for coating pipe parts or devices used to transport gaseous oxygen
WO2006092516A1 (en) * 2005-03-03 2006-09-08 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Method of coating a pipe element or device used to convey gaseous oxygen
JP2008531852A (en) * 2005-03-03 2008-08-14 レール・リキード−ソシエテ・アノニム・プール・レテュード・エ・レクスプロワタシオン・デ・プロセデ・ジョルジュ・クロード Method for coating pipe parts or devices used to transport gaseous oxygen
GB2443283A (en) * 2006-10-26 2008-04-30 Gen Electric Rub coating for gas turbine engine compressors
EP2413107B1 (en) * 2010-07-26 2020-04-08 Krohne AG Magnetic-inductive flow measuring apparatus
CN103867248A (en) * 2012-12-11 2014-06-18 瓦锡兰瑞士公司 Gas exchange valve and method for producing a gas exchange valve
EP2743468A1 (en) * 2012-12-11 2014-06-18 Wärtsilä Schweiz AG Gas exchange valve, and method for producing a gas exchange valve
EP2743468B1 (en) 2012-12-11 2019-09-04 Wärtsilä Schweiz AG Gas exchange valve, and method for producing a gas exchange valve
EP3106634A4 (en) * 2014-02-12 2017-11-29 Nittan Valve Co., Ltd. Poppet valve
WO2022133467A1 (en) * 2020-12-17 2022-06-23 Cummins Inc. Combustion cylinder end face components including thermal barrier coatings

Also Published As

Publication number Publication date
GB8926705D0 (en) 1990-01-17
GB2238349B (en) 1993-09-15

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 19961125