Patent US4939984A successfully refreshed from Google Patents.
US4939984A
Expired / Lapsed
US
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Investment-cast piston crown cap with encapsulated non-metallic insulating core
Assignee: AE PLC
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Filing: 1988-06-01
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Granted: 1990-07-10
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Expires: 2008-06-01
Abstract
Abstract Pistons for internal combustion engines, particularly compression ignition engines. The pistons have insulating crowns and include a crown having a cap thereon, extending over the crown surface area, the crown cap being composed of an iron-based or a nickel-based alloy and having on the underside thereof ribs which are encast into an aluminium alloy which forms the piston body. The crown cap further includes a ceramic insert encapsulated therein. The ceramic insert may also be leached out by chemical means to leave a void in the cap.
Inventors
- 👤 David F. Fletcher-Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:14
CPC Classifications
F; F02; F02B; F02B23/00; F02B23/02; F02B23/06; F02B23/0696; F02F; F02F3/00; F02F3/0015; F02F3/003; F02B23/0603; F02B2023/0612; F02B3/00; F02B3/06; F02F2200/00; F02F2200/06; F05; F05C; F05C2201/00; F05C2201/02; F05C2201/021; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49249; Y10T29/49256; Y10T29/49258
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
56 words
A piston for an internal combustion engine, the piston comprising a crown portion and a body portion, the crown portion having a cap extending over the surface area thereof, said crown cap being an investment casting of an iron-based or a nickel-based alloy, said investment casting also having encasted and encapsulated therein a non-metallic insulating core.
Claim 2
Dependent Claim
56 words
A piston for an internal combustion engine, the piston comprising a crown portion and a body portion, the crown portion having a cap extending over the surface area thereof, said crown cap being an investment casting of an iron-based or a nickel-based alloy, said investment casting also having encasted and encapsulated therein a non-metallic insulating core.
Claim 3
Dependent Claim
14 words
A piston according to claim 1 wherein said insulating core is a ceramic material.
Claim 4
Dependent Claim
31 words
A piston according to claim 1 wherein said insulating core has an array of holes or apertures therethrough which are filled by the iron-based or nickel-based alloy of said crown cap.
Claim 5
Dependent Claim
25 words
A piston according to claim 1 wherein at least part of said insulating core is removed by chemical leaching to leave a core shaped void.
Claim 6
Dependent Claim
23 words
A piston according to claim 1 wherein said crown cap further includes an annular portion having at least one piston ring groove therein.
Claim 7
Dependent Claim
30 words
A piston according to claim 1 wherein said crown cap further includes on the underside thereof ribs which are encasted in an aluminium alloy which forms the piston body portion.
Claim 8
Dependent Claim
12 words
A piston according to claim 6 wherein said ribs are radially directed.
Claim 9
Independent Claim
68 words
A method of making a piston having a crown portion and a skirt portion for an internal combustion engine, the method comprising the steps of making an iron-based or nickel-based alloy crown cap having therein an encasted and encapsulated ceramic core by an investment casting technique, placing the crown cap into a casting die and casting an aluminium alloy onto said crown cap to form said skirt portion.
Claim 10
Independent Claim
68 words
A method of making a piston having a crown portion and a skirt portion for an internal combustion engine, the method comprising the steps of making an iron-based or nickel-based alloy crown cap having therein an encasted and encapsulated ceramic core by an investment casting technique, placing the crown cap into a casting die and casting an aluminium alloy onto said crown cap to form said skirt portion.
Claim 11
Dependent Claim
22 words
A method according to claim 8 wherein at least part of said encapsulated ceramic core is removed by a chemical leaching technique.
Claim 12
Dependent Claim
21 words
A method according to claim 8 wherein said aluminium alloy is cast onto said crown cap using a pressure casting technique.
Claim 13
Dependent Claim
36 words
A method according to claim 8 wherein said encapsulated ceramic core is provided with an array of holes or apertures therethrough which are filled with the metal of the crown cap during the investment casting step.
Claim 14
Dependent Claim
18 words
A method according to claim 11 wherein said encapsulated ceramic core is removed by a chemical leaching technique.
Claim 15
Dependent Claim
13 words
A method according to claim 12 wherein said pressure casting technique is squeeze-casting.
Claim 16
Dependent Claim
18 words
A method according to claim 12 wherein said crown cap is provided with ribs on the underside thereof.
References Cited (Backward Citations)
FR869759A
Cited
US2880044A
Cited
US3152523A
Cited
DE1476142A1
Cited
DE1955903A1
Cited
US3616729A
Cited
CH578120A5
Cited
US3882841A
Cited
US4018194A
Cited
US4334507A
Cited
US4372194A
Cited
JPS54151715A
Cited
US4356800A
Cited
EP0084385A1
Cited
JPS58202347A
Cited
US4553472A
Cited
GB2125517A
Cited
GB2168126A
Cited
US4599772A
Cited
JPS60119348A
Cited
US4592268A
Cited
US4524498A
Cited
US4604945A
Cited
US4651630A
Cited
JPS60199561A
Cited
EP0185352A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-09 | 1994-01-08 | 1994-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-09 | 1998-01-08 | 1998-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-09 | 2002-01-08 | 2002-07-10 | $7700.00 | Window Closed / Lapsed |