Lightweight piston
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorAllan H. Taylor
Life of this patent
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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.
Claims18
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.
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.
A piston according to calim 7 wherein said carbonaceous resin is phenolic resin.
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.
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.
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.
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.
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.
Dependencies are inferred from the claim text.