Internal-combustion engines – Particular piston and enclosing cylinder construction – Piston
Patent
1999-08-27
2000-09-12
McMahon, Marguerite
Internal-combustion engines
Particular piston and enclosing cylinder construction
Piston
29888046, C04B 3583, C04B 3580, F16J 101
Patent
active
061162035
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to manufacturing a piston for an internal combustion engine out of thermostructural composite material, i.e. a material that comprises fiber reinforcement of refractory fibers densified by means of a matrix of refractory material.
BACKGROUND OF THE INVENTION
Thermostructural composite materials are characterized by their mechanical properties which make them suitable for constituting structural elements, and by their ability to retain these properties up to high temperatures. These materials are in particular carbon/carbon (C/C) composite materials comprising reinforcement made of carbon fibers embedded in a carbon matrix, and ceramic matrix composite (CMC) materials comprising reinforcement of refractory fibers, such as carbon or ceramic fibers, embedded in a ceramic matrix.
Because of their properties, thermostructural composite materials can replace metal materials for making parts that are subjected to mechanical forces and that are liable to be exposed to high temperatures.
Thus, proposals have already been made to make pistons for internal combustion engines out of C/C composite material. In addition to withstanding temperature, C/C composite materials have the advantage of density that is much smaller than that of metals, thereby making it possible to reduce moving masses and to increase the maximum speed of rotation of the engine. In addition, the low thermal expansion of the material and its good tribological properties greatly reduce the risk of the piston seizing or binding, thereby making it possible to increase the reliability of the engine and reduce its requirements for lubrication.
Reference can be made to document U.S. Pat. No. 4,909,133 which describes the manufacture of a piston by making an article of fiber reinforcement, or "preform", as a single piece in the form of a knitted "sock" of carbon fibers, impregnating the preform with a resin for molding and densification by means of a carbon matrix by using a liquid process (impregnation with the resin followed by carbonization) and finished off by a gas process (chemical vapor infiltration).
Document DE-A-29 12 786 also describes making a C/C composite material piston by winding a carbon thread and then impregnating with a carbon-containing resin. The outside surface of the piston on its side that is exposed to combustion gases is coated in a protective layer of silicon carbide.
In a C/C composite material piston, it is necessary to ensure that the reinforcement fibers are oriented in directions that are suitable for the forces to which the piston is subjected in operation. The techniques described in the two above-mentioned documents can satisfy that condition, but in a manner that is expensive. They require preforms to be made individually in relatively complex manner: knitting a "sock" or winding a filament over a predetermined path.
BRIEF SUMMARY OF THE INVENTION
An object of the invention is to provide a method of manufacturing a piston of thermostructural composite material in which the preparation of the preform is simplified compared with the above state of the art, so that manufacturing costs can be substantially reduced.
In a first aspect of the invention, this object is achieved by a method which comprises the steps consisting in: the plies together by needling, so that the fibers of the superposed plies extend essentially in a first direction (X) and in a second direction (Y) orthogonal thereto, the plies being bonded together by fibers that are displaced by the needling in a third direction (Z) that is transverse relative to the plies; of the first and second directions (X, Y) is parallel to the generator lines of the surface of the preform that corresponds to the cylindrical side surface of the piston; the matrix; and
Preferably, the method further comprises the steps consisting in:
The invention is remarkable in that the piston preforms or blanks are obtained from a fiber structure that is made simply by needling superposed plies in which the fibers are essentiall
REFERENCES:
patent: 4790052 (1988-12-01), Olry
patent: 4852630 (1989-08-01), Hamajima et al.
patent: 4909133 (1990-03-01), Taylor et al.
patent: 5154109 (1992-10-01), Fluga et al.
patent: 5740788 (1998-04-01), Atmur et al.
patent: 5900193 (1999-05-01), Rivers et al.
patent: 5948330 (1999-09-01), Rivers et al.
patent: 6029346 (2000-02-01), Chellappa
Ciais Jean-Pierre
Thebault Jacques
McMahon Marguerite
Societe Nationale d'Etude et de Construction de Moteurs d'Aviati
LandOfFree
Method for making an internal combustion engine piston in thermo does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for making an internal combustion engine piston in thermo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for making an internal combustion engine piston in thermo will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-86742