Abstract: Noncontacting surface areas are provided between the top wall of an oil control ring and the top surface of its groove to avoid entrapment of oil between adjacent surfaces of the two members during downward motion of a piston in a reciprocating, internal combustion engine. The noncontacting surface areas may be provided by circular grooves formed in the top surface of the groove or the ring. Alternatively, either the top surface of the groove or the top wall of the oil control ring may be formed so that it slopes away from the surface of its mating member and forms a tapered annular cavity that diverges away from the outer cylindrical surface of the piston. All of the described arrangements reduce the contact area between the top of the ring and the top of the groove during downward movement of the piston, thereby permitting the oil control ring to seal against the upper surface of its groove.

Abstract: This invention relates to a piston arrangement for minimizing water blow-by in a cylinder bore, comprising a set of metallic compression and oil rings, and a resin-filled O-ring for reducing water blow-by in the cylinder bore until the set of metallic compression and oil rings are properly seated in the cylinder bore.

Abstract: In order to improve the guidance of a light-metal piston for an internal combustion engine of a motor vehicle by obtaining a uniform behavior under different stresses of the pressure and/or counter pressure side of the piston skirt, the wall thickness of the piston skirt is made different in the region of its pressure and/or counterpressure regions from that in its other regions. In the pressure and counterpressure regions, there is a thickening on the inner side of the piston skirt which is gradually reduced from the lower edge of the skirt in a central plane in the piston length and pressure/counterpressure direction back to the normal thickness.

Abstract: The piston of this invention is so profiled that the diametric reduction of the shoulder portion of the skirt is greater on the thrust side than on the counter-thrust side and that the difference in diametric reduction between the thrust side and the counter-thrust side is maximum at around a position corresponding to the center of the piston pin. In the compression stroke, the piston moves up pressed against the cylinder liner wall on the counter-thrust side but the inclination angle of the piston at this time is small. Near the top dead center, the piston is rapidly pivoted and strikes against the cylinder liner wall on the thrust side. The point on the piston hitting the cylinder liner wall is at around a position equal in height to the center of the piston pin. This reduces the impact force of the piston and therefore the slap.

Abstract: A piston--piston ring assembly for an internal combustion engine reduces hydrocarbon emissions without significantly increasing the cost of the engine. The assembly includes an upper piston ring groove and a piston ring which acts as check valve to prevent combustion gases trapped below the upper piston ring from re-entering the combustion chamber when the exhaust valve is opened. The invention also includes a venting means for providing fluid flow communication between the crankcase side of the upper piston ring and the crankcase, around one or more lower piston rings, so that any trapped combustion gases are vented only in the downward direction toward the crankcase. The venting means includes a vent passageway slot in the lower piston groove, as well as an aperture adjacent to the lower piston ring groove.

Abstract: This invention relates to a piston with its skirt being cut to locate four sets of bearing pads and circulating roller bearings. Each pad has been milled to have a doughnut shaped groove with half of a roller cross-section to hold the roller bearing in circulation during the piston reciprocating motion. Two lines of roller bearings on each side of a piston pin are in contact with the cylinder liner and share the piston thrust load. Lubrication of the roller bearings is ensured by oil slots through the piston skirt under the oil ring groove to the top of the grooves of the bearing pads and to the exposed roller bearings in rolling contact.

Abstract: Piston unit used in an internal combustion engine, which allows no interfacial crack between a piston and a wear-proof ring as well as allowing to provide T6 treatment to aluminum base alloy used for the piston. The piston unit has a piston formed of aluminum base alloy, and a wear-proof ring that has been fused with a first ring groove of the piston. The wear-proof ring is formed of copper-zinc alloy with its thermal expansion coefficient ranging from 19.5.times.10.sup.-6 m/m to 22.0.times.10.sup.-6 m/m. The copper zinc alloy may contain 63 wt. % of copper, 30 wt. % of zinc, 15 wt. % of aluminum, and 4% of titanium, or it may contain 70 wt. % of copper and 30% of zinc only.

Abstract: A two-piece, or articulated, piston head for internal combustion engines having top and pin boss portions in which the underside of the top portion is provided with a groove whose inner wall is eccentric in relation to the longitudinal axis; of the top and the upper side of the top portion is provided with a combustion bowl eccentric in relation to the top portion longitudinal axis and concentric with the inner wall of the groove on the underside of the top portion.

Abstract: A piston having at least one piston ring in combination with a cylinder of a two-stroke internal combustion engine. The piston is made from an aluminum alloy and has a running layer covering at least 80% of the running surface of the piston. The running layer is made from resin-bound graphite. The piston ring has a crowned running surface and is made from cast iron or steel. The cylinder includes a running surface where at least the running surface is made from an aluminum alloy. The running surface has a roughness of less than 1 micron. The running layer on the piston has a thickness between 10 and 20 microns. The graphite particles which form the running layer have a size between 1 and 10 microns.

Abstract: Metallic piston, wrist pin and connecting rod which normally do not fit together can be joined with one selected component being heated to effect the expansion thereof while another selected component is chilled to effect its contraction. With the heat differentials effecting relative size change the components can be loosely put together in a preassembly. The components in the loose preassembly are then returned to ambient temperature and to specification size whereby a central journal of the wrist pin is trapped between the piston pin bosses in one embodiment and the connecting rod is trapped by the shoulders of a reduced diameter pin journal in a second embodiment to form permanent piston, connecting rod and wrist pin assemblies.

Abstract: The piston made in accordance with the teachings herein includes a primary compression ring groove, a bottom and rear wall surface of which are hardened by the method of laser hardening. The method includes the steps of spraying the primary groove with a graphite spray and then directing an angled elliptical in cross section laser beam at the bottom surface of the groove while rotating the cylinder head at predetermined parameters.

Abstract: A piston for an internal combustion engine, and particularly, but not exclusively, for a Diesel engine, has in a region thereof reinforcing ceramic fibres, the fibres originally being in the form of an insert for the piston with a relatively high density in the range 10 to 20% of the density of the fibre material. In the fabrication of the piston the insert is infiltrated with molten piston material, the piston being formed by employing a pressure casting technique, such as squeeze casting. The piston material comprises an aluminum alloy with 2.0 to 5.5% by weight copper and with 11.0 to 17.0% by weight silicon, and, preferably, 2.5 to 3.5% by weight copper and 12 to 14% by weight silicon. In the fibre-reinforced region the top ring groove of the piston is provided, and, possibly, the fibre-reinforced piston region provides the peripheral part of the crown surface.

Abstract: A piston for an internal combustion engine. The piston has upper and lower compression rings and a recess between the two which exposes a greater proportion of the ring end gap for the lower compression ring. As a result, the space between the rings and below the lower compression ring provides a capacitance volume to minimize top ring reversal.

Abstract: The present invention discloses an internal combustion piston engine having a cylinder and a piston, the cylinder having an internal cylindrical bore and an inner wall, the piston being slidable within the cylinder, the piston having a top portion and a skirt portion below the top portion, the skirt having a wide portion with a diameter greater than the diameter of the cylinder bore, the piston being made of a resiliently deformable material and, upon insertion into the cylinder, the piston deforms such that there is no clearance between the wide portion of the piston and the inner wall of the cylinder. The skirt portion of the piston may also have an elliptical cross-sectional profile, the elliptical cross-sectional profile having a long axis longer than the inside diameter of the cylinder and a short axis shorter than the inside diameter of the cylinder.

Abstract: A piston assembly such as that used with an internal combustion engine includes an annular cylinder having an inner cylinder wall defining a bore. An annular piston is reciprocal along a longitudinally extending axis within the bore of the cylinder. The piston includes two grooves that define the angled walls of a generally keystone wedge. A single strip of metal is formed into a one-piece split annular top land type piston ring with little or no intrinsic load. The piston ring is adapted to be received within the grooves of the piston to provide sealing engagement between the piston and the cylinder wall. The shape of the piston ring and the wedge of the piston provide a smooth sliding movement between the mating components as a dynamic force component is created in a radial direction in response to piston reciprocation along the longitudinal axis of the cylinder.

Abstract: This invention relates to a piston with its skirt being cut to locate four sets of bearing pads and circulating bearing balls. Each pad has been milled to have a doughnut shaped groove with half of a circle cross-section to hold the ball bearing in circulation during the piston reciprocating motion. Two lines of bearing balls on each side of a piston pin are in contact with the cylinder liner and share the piston thrust load. Lubrication of the ball bearings is ensured by oil slots through the piston skirt under the oil ring groove to the top of the grooves of the bearing pads and to the exposed bearing balls in rolling contact.

Abstract: A piston for an internal combustion engine comprising a piston head provided with at least one piston ring groove and a piston body having a piston pin bore, and a compression height of less than 40% of the piston diameter. In order to be able to equalize the influences of thermal expansion as well as possible and to enable a quiet operation of the piston in a cylinder, the invention provides that the largest diameter region of the piston body is arranged in a plane which extends perpendicularly to the body-generating line and which includes the piston pin axis.

Abstract: The invention relates to a piston, particularly of light metal, for internal combustion engines, comprising a piston skirt substantially closed in the peripheral direction, pin bosses set back with respect to the piston skirt diameter in the direction of the piston axis, and two supporting skirt wall sections which thus remain on the piston skirt on the thrust and the counter-thrust side. The supporting skirt wall section on the thrust side is larger at least in the peripheral direction of the skirt than the supporting skirt wall section on the counter-thrust side.In order to divert the lateral forces acting on the supporting surfaces to the entire supporting structure in an elastically cushioned but safe manner, the two wall sections of the skirt connecting the supporting wall sections are respectively continuously curved convexly outwards as seen along the periphery of the piston skirt at least at the open skirt end beneath the pin bosses.

Abstract: The design and construction of past piston assemblies having a wrist pin retained by a pair of snap rings positioned in a groove. Other past piston assemblies have a stubpin or cap positioned within a bore of a piston member or the wrist pin. In these applications the stubpin or cap is in continuous contact along the interface between the bore and the stubpin or cap. The present invention provides a device for retaining a wrist pin within a pair of bores of a piston member during operation of an engine. The device includes a shank portion having an outer portion thereon and only the outer portion of the shank portion being in contact with an inner surface of the wrist pin. The device and the wrist pin forming a wrist pin assembly. Thus, the device remains positioned within the inner surface and properly positioned the wrist pin assembly within the bores during operation of an engine within a bore of a cylinder liner.

Abstract: This invention relates to a fluid sealing mechanism for the inside diameter and or the outside diameter of a piston-cylinder arrangement. This device results in zero seal leakage path with low differential seal pressure required using only one piston ring, one ring groove, and very loose dimensional tolerances required on both the ring and related groove. This yields an inexpensive more positive seal for fluid piston-cylinder configuration used in industrial, commercial, and personal use.

Abstract: A piston having a crown, a head land depending downwardly from the crown, a skirt and at least one groove between the head land and the skirt to receive a piston ring wherein the head land is provided with a part which has a greater cross-sectional dimension than any portion of the piston between said part and the skirt.

Abstract: A wrist pin is provided for connecting a connecting rod to a piston, comprising a cylindrical aluminum pin having an outer cylindrical surface, the pin being matingly insertable into a bore of a piston, the outer cylindrical surface having an anodized coating applied thereto. A process for manufacturing a wrist pin is also provided, comprising the steps of machining a cylindrical pin, having an outer cylindrical surface, from aluminum stock; and applying an anodized coating to the outer cylindrical surface. The preferred anodized coating comprises a hardcoat anodized coating.

Abstract: A method for the manufacture of a cooled piston head in which the upper and lower portions of the piston head are made separately; a metal plate is placed on the lower side of the upper portion; the upper portion incorporating the metal plate is joined to the lower portion by friction welding. The metal plate is provided with a central hole for the passage of cooling oil onto the undercrown, and means of communication with a closed cooling chamber defined by a circumferential groove on the head upper portion and the peripheral outer surface of the metal plate.

Abstract: In a piston, a circumferential groove for a piston ring, a knock pin being inserted in a bore set radially relative to the piston ring groove. A head end of the knock pin protrudes into a space defined by the piston ring groove for interposing between ends of a piston ring for preventing turning, or rotation, thereof. Means for preventing mechanical interference between the walls of the piston ring groove and the head end of the knock pin is provided.

Abstract: A method for the manufacture of a piston head having a cooling chamber is disclosed. The two portions composing the piston head are made separately; the underside of the upper portion is provided with a circumferential peripheral groove; notches are provided on both sides of the open end of the circumferential peripheral groove; a circumferential annular plate is placed on the notches thereby closing the circumferential peripheral groove; the two portions making up the head are joined to each other by welding and cause the inner edge of the annular plate to be retained in the piston head and become an integral part thereof.

Abstract: A piston having a head with ring grooves, a skirt having hub bores, and a pin, with the following dimensions:L/D=0.45-0.8H/D=0.25-0.5A/D=0.3-0.5T/D=0.45-0.8whereL=maxium length of the pistonD=maximum diameter of the pistonH=compression heightA=maximum skirt height below the bottom ring groove in a peripheral area having the approximate same skirt height of at least 45 degrees on the major thrust face of the piston with approximately symmetrical division of this area on both sides of a plane extending perpendicular to the pin axis and passing through the longitudinal axis of the piston,T=diametrically opposite distance between the hub bore ends located radially on the outside.The skirt bulges along the axis of the piston and has an oval cross-section. An axis of the hub bores is offset slightly towards the major thrust face. The piston includes a horizontal slit, which separates the head from the skirt. In a polar plane perpendicular to the piston axis the skirt has a greater ovality on the minor thrust face.

Abstract: A piston for an internal combustion engine with a separate head and skirt which are joined by a piston pin. The ring belt extends downward from the head and terminates above the pin. The space between the lower edge of the ring belt and a section of the head defines a cooling oil ring space. A depression is formed in the head and is partly defined by the section. The section has a thickness of between four percent and seven percent of the piston diameter, corresponding to an angle of zero to sixty degrees of the section with respect to a vertical longitudinally extending line. The thickness of the head above the space is six percent to twelve percent of the piston diameter. The top of the space is below the top ring groove. Above the second ring groove, the ring belt has a thickness of greater than two and one-half percent of the piston diameter.

Abstract: A piston assembly is disclosed having a wrist pin for pivotably attaching a connecting rod to a piston for use in an internal combustion engine. The wrist pin is formed from an elongated circular cylindrical body having a pair of deformable sections formed adjacent each end and a relatively hard middle section therebetween. The wrist pin is sized for insertion along a longitudinal axis defined by a pair of coaxially aligned, spaced apart bores formed in diametrically opposed portions of the piston. The deformable end sections are adapted to be deformed sufficiently to engage the bores of the piston to limit the axial movement therebetween. The relatively hard middle section spans between the bores in the piston for pivotably engaging one end of the connection rod.

Abstract: A piston 2 for an internal combustion engine includes side wall portions 12 connecting skirt portions 10 to pin boss portions 6 so as to support the skirt portions 10 in a direction perpendicular to an axis 8 of the pin boss portions. The skirt supporting stiffness of each side wall portion 12 is gradually changed in an axial direction of the piston 2 so as to have a maximum stiffness at a lower end portion of the side wall portions b 12 and to decrease in the direction upwardly away from the lower end portion of the side wall portion 12. Due to this structure, the skirt portion 10 is unlikely to be deformed at its lower end portion so that a clearance between the skirt portion 10 and a cylinder bore surface 20 is maintained small. Further, the skirt portion 10 has a soft structure at the shoulder of the skirt portion 10 so that a shock at the shoulder will be decreased to prevent breakage of an oil membrane from happening at the upper portion of the skirt portion 10.

Abstract: In a light alloy piston for internal combustion engines the mounting for the piston pin is designed for heavy loads. The piston comprises piston pin bosses which are integrated in the skirt of the piston and provided with an inelastic block support. In order to reduce the weight those end faces of the piston pin bosses which face the small end of the connecting rod are outwardly setback below those segments of the top apex portions of the bosses which include an angle of less than 180 degrees.

Abstract: A novel prefinished piston pin insert bearing is described wherein the tight radial clearances required for acceptable bearing function are maintained in spite of the tolerances required for assembly through a unique inner bearing surface geometry and through a unique methodology of bearing retention against axial and rotational movement. The interior bearing geometry is formed of radii equal to that of the piston pin which are offset vertically into the upper and lower bearings and of radii of nonspecific size which are offset horizontally. The bearings are retained against movement through connections with the piston head, the piston skirt, and between the various bearing pieces. Means are also provided for feeding oil under pressure to the piston pin and bearing interface for lubrication and to the piston assembly for cooling.

Abstract: A method for the manufacture of a two-piece piston wherein the top portion and the pin boss portion, which define the piston head, are fabricated separately by cold or hot forming, casting or sintering, and joined together by welding such as, for instance, friction welding. The top portion and the pin boss portion may be of the same material or different materials, and obtained by the same method or by different methods.

Abstract: A substantially circumferential annular member is installed in the region defined by the rear face of a piston compression ring and the upper and lower walls and the bottom of the compression ring groove. The annular member moves within said room by the action of inertia forces arising out of the piston reciprocating motion, thereby preventing the build-up of carbon particles in the piston compression ring groove.

Abstract: A piston comprises a crown part, a piston under part, a first shoulder at a thrust side formed between the crown part and the piston under part, a second shoulder at an anti-thrust side formed between the crown part and the piston under part, a first in-low part at the thrust side formed in the piston under part, and a second in-low part at the anti-thrust side formed in the piston under part, wherein a thickness of the first shoulder is formed thinner than a thickness of the second shoulder, and a height of the first in-low part is formed smaller than a height of the second in-low part.

Abstract: Gas cushions are maintained between a piston and a cylinder of a gas lubricated reciprocating engine which are effective in retarding the approach of the piston to the cylinder wall under the thrust of side forces from the connecting rod. The cushion are maintained by viscous flow forces for sufficient time exceed a half cycle of crankcase rotation.

Abstract: The technical problem is to reduce the operating noise of such a piston. It is solved by means of a piston having the following dimensions: a) A=(0.45-0.65) D; b) H=(0.25-0.4) D; c) A=(0.3-0.4) D; d) A greater than or equal to B; e) T=(0.45-0.8) D; f) the piston ribs between the annular grooves (2, 3, 4) and the rod region with a very narrow operating clearance have, in the case of a hot operating piston, approximately the same clearance in relation to the cylinder operating path. An additional improvement consists in inserting an annular jacket in the piston head in the radial region behind the annular grooves, said jacket consisting of a material having a thermal expension factor less than that of the basic piston material. In a hot operating internal combustion engine, the piston has, in the region of the ribs, a clearance which, in the direction pressure/counter-pressure reaches approximately only 3-5 times the clearance in the very narrow clearance region of the piston rod.

Abstract: A piston structure includes protection of the peripheral edge portion of a lubricant injection nozzle receptacle cut-out. The piston structure employs mechanisms for reinforcing the peripheral edge portion of the cut-out to an extent that can avoid concentration of the stress and thus can avoid the formation of cracks.

Abstract: A piston assembly of an internal combustion engine is provided with a piston structure with which oil comsumption is suppressed. A piston of the assembly is disposed inside each cylinder wall of the engine and formed with a top land and the second land. A compression ring groove is formed between the top and second lands. A first chamfered surface is formed at the upper peripheral edge of the second land, and a second chamfered surface larger in width than the first chamfered surface is formed at the lower peripheral edge of the top land. A compression ring having a butt-type ring gap is disposed in the compression ring groove to be slidably contacted with the cylinder wall. With this structure, the oil comsumption is effectively suppressed in both high pressure and negative pressure conditions during operation of the combustion chamber corresponding to the cylinder.

Abstract: A piston is formed with a cooling channel in its crown by dissolving a fusible core cast into the crown. The fusible core is supported prior to casting by a strut which is itself supported on a plurality of cores which help to find the piston cavity. The plurality of cores are configured so as to be removable from the strut, after casting, in a downward direction. The fusible core is dissolved by introducing a dissolving liquid to the fusible core via inlet or outlet passages cut between the cavity and the fusible core.

Abstract: This invention relates to a mounting structure of a multiple piston ring for various internal combustion engines. A plurality of piston rings are all wrapped in a cylindrical groove formed upon an outer surface of a piston so that a gap of one piston ring cannot face to a gap of the other piston ring, namely respective gaps of the plurality of piston rings are spaced each other with a certain distance. In order to prevent such a facing of two or more gaps that may occur due to a rotation of the piston rings, a stop pin is mounted on a piston wall so as to engage with a gap of one piston ring or formed as a convex protrusion on one piston ring so as to engage with a gap of the other piston ring. Since respective gaps of the piston rings are not faced to each other, it is possible to prevent any back pressure gas leakage from such gaps of the piston rings.

Abstract: A piston assembly comprising a piston reciprocally movable along an axis and including a generally cylindrical outer surface having therein a circumferentially extending groove partially defined by a surface having therein a recess, and a piston ring located in the groove and including a lower surface extending generally perpendicularly to the axis, a first arcuate segment having an upper surface inclined radially inwardly and downwardly and having a maximum thickness and a radially inwardly decreasing thickness, and a second arcuate segment extending into the recess and having a substantially constant thickness across the radial extent thereof, the constant thickness being substantially equal to the maximum thickness.

Abstract: In a light alloy piston each of the load-carrying skirt surfaces is divided into a plurality of load-carrying skirt surface portions. In order to ensure that the upper portion of the piston skirt will carry load on a large area even when the engine is warming up, a plurality of depressions extending in the peripheral direction of the piston skirt are formed in the latter between its clearance-defining top and bottom ends.

Abstract: A piston generates reduced noise in operation by the provision on its lateral bearing surfaces of two or more depressions in which oil is stored to provide a cushion against lateral movement of the piston at points of a reciprocation of the cycle where noise is generated. The depressions have a maximum depth of only 125 microns below the surrounding bearing surfaces formed on the piston. The depressions have circumferentially extending edges which are formed with steps connecting the depressions to the surrounding bearing surface.

Abstract: A continuous ring with inside diameter (D.sub.in.sup.R) larger than the outside diameter (D.sub.out.sup.R) of the piston irrespective of conditions of operation. The ring's outside diameter when measured outside the cylinder equals or slightly exceeds the inside diameter of the cylinder. The ring is sized and designed according to various parameters determined so as to prevent piston seizing in the cylinder.

Abstract: Piston for internal combustion engines, with an oil scraper ring disposed in an annular groove at the circumference of its head portion. The outer edge of the annular groove adjacent to the piston skirt which adjoins the head portion is bevelled to form a chamfer. In order to ensure the maintenance of an oil film sufficient to prevent dry running of the piston, on the cylinder wall, the width of the chamfer is greater on the thrust side of the piston. The width of the chamfer may decrease essentially continuously from the counter-thrust side to the pressure side.

Abstract: A piston has skirt portions (13) which are provided with parallel rows (14) of cavities (15) whose maximum depth below the surface of the skirt portion is 0.010 mm. Parts (20,23) of the skirt portion are left between the cavities for providing a reduced area, in comparison with the full skirt portion, for the transmission to an associated cylinder or liner of lateral loads; this reduced area reducing the frictional losses. The cavities (15) hold lubricating oil and provide a cushion of oil which supplies oil to the reduced bearing areas and which tends to resist lateral movement of the piston at top and bottom dead center, so reducing or eliminating "piston slap".

Abstract: A piston casting for forming a piston for an internal combustion engine or compressor comprises a generally cylindrical crown (10) having a ring belt (11) extending around the crown for the formation therein of one or more piston ring grooves. A gudgeon pin bore (14) extends through the piston casting in a direction normal to the piston axis and two opposed skirt thrust surfaces (17) depend from the ring belt and are symetrically disposed about a plane including the piston axis and normal to the gudgeon pin bore axis. The surfaces extend only part the way around the piston casting and terminate in respective spaced generally axially extending edges (18), each skirt thrust surface being extended circumferentially beyond the associated edges (at 19) at the ends of the edges remote from the crown.

Abstract: An extremely light and low friction plunger piston for internal combustion engines, particularly Otto-type engines for private cars. The piston has the following ratios and dimensions(H/D)=0.20-0.35(T/D)=0.22-0.38(A/D)=0.15-0.25(B/D)=(A/D)whereinD=piston diameterH=compression height between a top of the head and the gudgeon pin bore axisT=distance from the radially outer boss faces to the piston axisA=axial skirt dimension below annular groove nearest the pin bore axis at a peripheral zone of the skirt extending over an angle .alpha. of 15 to 60 degrees to either side of a connecting rod oscillating planeB=axial skirt dimension below said annular groove in a direction along said gudgeon pin axis;and further wherein the distal end of the skirt is reduced radially over an axial dimension of 10-25% of an axial length of the skirt in said direction along said gudgeon pin axis, said distal end being reduced at its edge by 0.01-0.15 mm.

Abstract: A piston for internal-combustion engines, reinforced at least at either the shoulder of the skirt or the piston boss thereof by a composite reinforcement consisting of a layer of inorganic long filaments and a layer or layers of inorganic staple short fibers or whiskers. The inorganic filaments are one or a combination of any of carbon, graphite, alumina, silicon carbide and glass, while the inorganic staple fiber or whiskers are silicon nitride whiskers, mineral fibers, potassium titanate whiskers, carbon fibers or graphite fibers, or a combination of those whiskers and/or fibers.

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.