US4683809A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lightweight piston
Assignee: National Aeronautics and Space Administration
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Filing: 1985-05-02
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Granted: 1987-08-04
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Expires: 2005-05-02
Abstract
Abstract A lightweight piston 12 composed of carbon-carbon is disclosed. The use of carbon-carbon over conventional materials, such as aluminum, reduces piston weight and improves thermal efficiency of the internal combustion reciprocating engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall 10 clearance is so small as to eliminate the necessity of piston rings. Use of the carbon-carbon piston has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance.
Inventors
- 👤 Allan H. Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:33
CPC Classifications
F; F16; F16J; F16J1/00; F16J1/001; F02; F02F; F02F7/00; F02F7/0085; F16J1/02; F05; F05C; F05C2203/00; F05C2203/08; F05C2203/0804; F05C2203/0808; F05C2253/00; F05C2253/16; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49249; Y10T29/49256
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
83 words
The method of making a carbon-carbon piston comprising the steps of: placing a precursor fiber in a mat or random fiber orientation in a closed die; pyrolizing said precursor fibers; impregnating said precursor fibers with a carbonaceous resin system; stretching said precursor fiber prior to or during stabilization; stabilizing said material by heating the fiber in air; carbonizing said material by slowly heating the fiber in an inert atmosphere; and graphitizing said fibers by raising the temperature to the desired heat treatment temperature.
Claim 2
Independent Claim
83 words
The method of making a carbon-carbon piston comprising the steps of: placing a precursor fiber in a mat or random fiber orientation in a closed die; pyrolizing said precursor fibers; impregnating said precursor fibers with a carbonaceous resin system; stretching said precursor fiber prior to or during stabilization; stabilizing said material by heating the fiber in air; carbonizing said material by slowly heating the fiber in an inert atmosphere; and graphitizing said fibers by raising the temperature to the desired heat treatment temperature.
Claim 3
Dependent Claim
39 words
The method of making a carbon-carbon piston as in claim 1 wherein the precoursor fiber is stretched about 80% prior to or during stabilization, and the material is stabilized by heating the fiber at 220° C. for 23-25 hours.
Claim 4
Dependent Claim
28 words
The method of making a carbon-carbon piston as in claim 1 wherein the material is carbonized by slowly heating the fiber in an inert atmosphere to 1000° C.
Claim 5
Dependent Claim
31 words
The method of making a piston according to claim 1 wherein upon completion of the final pyrolysis cycle, piston outside diameter and wrist pin holes are machined using conventional machinery operations.
Claim 6
Dependent Claim
37 words
A method of making a piston as in claim 1 which includes the additional steps of adding oxidation inhibitors to said material during the impregnation cycle to avoid the possibility of blowby causing piston erosion or oxidation.
Claim 7
Dependent Claim
31 words
The method of making a piston according to claim 1 and further including the steps of: fitting said piston to the cylinder by lapping said piston to precisely fit the bore.
Claim 8
Dependent Claim
33 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material.
Claim 9
Dependent Claim
33 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material.
Claim 10
Dependent Claim
12 words
A piston according to claim 7 wherein said precursor fiber is rayon.
Claim 11
Dependent Claim
13 words
A piston according to claim 7 wherein said precursor fiber is polyacrylonitrile (PAN).
Claim 12
Dependent Claim
13 words
A piston according to claim 7 wherein said carbonaceous resin is furfuryl alcohol.
Claim 13
Dependent Claim
13 words
A piston according to calim 7 wherein said carbonaceous resin is phenolic resin.
Claim 14
Dependent Claim
13 words
A piston according to calim 7 wherein said carbonaceous resin is phenolic resin.
Claim 15
Dependent Claim
31 words
A carbon-carbon piston as in claim 7 wherein the carbon-carbon piston is coated with a high temperature oxidation resistant material such as silicon carbide developed for avoiding piston erosion or oxidation.
Claim 16
Dependent Claim
54 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of a precursor material impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston having a crown area reinforced with unidirectional fibers or cloth layered in a 0, ±45, 90 orientation.
Claim 17
Dependent Claim
54 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of a precursor material impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston having a crown area reinforced with unidirectional fibers or cloth layered in a 0, ±45, 90 orientation.
Claim 18
Dependent Claim
46 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of a precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston having wrist pin boss areas reinforced with unidirectional fibers.
Claim 19
Dependent Claim
46 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of a precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston having wrist pin boss areas reinforced with unidirectional fibers.
Claim 20
Dependent Claim
52 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of a precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston having wrist pin boss areas reinforced with cloth layered in a 0, ±45, 90 orientation.
Claim 21
Dependent Claim
52 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of a precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston having wrist pin boss areas reinforced with cloth layered in a 0, ±45, 90 orientation.
Claim 22
Dependent Claim
56 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of a precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston being impregnated with a high temperature oxidation resistant material such as boron developed for avoiding piston erosion or oxidation.
Claim 23
Dependent Claim
56 words
An improved piston for an internal combustion engine comprising: a carbon-carbon piston means composed of a precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston being impregnated with a high temperature oxidation resistant material such as boron developed for avoiding piston erosion or oxidation.
Claim 24
Dependent Claim
81 words
An improved piston for an internal combution engine comprising: a carbon-carbon piston means composed of a precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston being operable in a cylinder wall of a internal combustion engine, the wall of said cylinder being composed of a carbon-carbon sleeve inserted in a cylinder block area; whereby said cylinder wall improves specific engine power by increasing thermal efficiency and lowering coolant loss.
Claim 25
Dependent Claim
81 words
An improved piston for an internal combution engine comprising: a carbon-carbon piston means composed of a precursor fiber impregnated with a carbonaceous resin; said piston being constructed without piston grooves and without reinforcing material; and said piston being operable in a cylinder wall of a internal combustion engine, the wall of said cylinder being composed of a carbon-carbon sleeve inserted in a cylinder block area; whereby said cylinder wall improves specific engine power by increasing thermal efficiency and lowering coolant loss.
Claim 26
Dependent Claim
30 words
An improved piston for an internal combustion engine as in claim 17 wherein axially wrapped cloth is used as a precursor material for the carbon fibers of the carbon-carbon sleeve.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-03 | 1991-02-02 | 1991-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-03 | 1995-02-02 | 1995-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-03 | 1999-02-02 | 1999-08-04 | $7700.00 | Window Closed / Lapsed |