Abstract:
An improved structure for carbon-carbon composite piston architectures is disclosed. Initially, the carbon fabric or tape layers are prepregged with carbonaceous organic resins and/or pitches and these plies (21) laid up or molded about a mandrel, to form a carbon-fiber reinforced organic-matrix composite billets (20) shaped like a "U" channel having legs (26, 27), a "T"-bar, or a combination of the two. The molded carbon-fiber reinforced organic-matrix composite part is then pyrolized in an inert atmosphere, to convert the organic matrix materials to carbon. At this point, cylindrical piston blanks (22) are cored from the "U"-channel, "T"-bar, or combination part. These blanks are then densified by reimpregnation with resins or pitches which are subsequently carbonized. Densification is also accomplished by direct infiltration with carbon by vapor deposition processes. Once the desired density has been achieved, the piston billets are machined to final piston dimensions; coated with oxidation sealants; and/or coated with a catalyst.
Abstract:
A three-dimensional piston molding is fabricated from a mixture of chopped, carbon tow filaments of variable length, which are prepregged with carbonaceous organic resins and/or pitches and molded by conventional molding processes into near net shape, to form a carbon-fiber reinforced organic-matrix composite part. Continuous reinforcement in the form of carbon-carbon composite tapes or pieces of fabric can be also laid in the mold before or during the charging of the mold with the chopped-fiber mixture, to enhance the strength in the crown (21) and wrist-pin areas (23). The modled chopped-fiber reinforced organic-matrix composite parts are then pyrolyzed in an inert atmosphere, to convert the organic matrix materials to carbon. These pyrolyzed parts are then densified by reimpregnation with resins or pitches, which are subsequently carbonized. Densification is also accomplished by direct infiltration with carbon by vapor deposition processes. Once the desired density has been achieved, the piston molds are machined to final piston dimensions, and piston ring grooves are added. To prevent oxidation and/or to seal the piston surface or near surface, the chopped-fiber piston (20) is coated with ceramic and/or metallic sealants; and/or coated with a catalyst.
Abstract:
Present day diesel engines having aluminum piston assemblies are limited to combustion chamber pressures of approximately 12,410 kPa (1,800 psi) whereas the desire is to increase such pressures up to the 15,170 kPa (2,200 psi) range. To reach such levels the instant engine has a piston assembly (76) including a steel piston member (78) having an upper cylindrical portion (96) of a diameter D and defining a top surface (98), a depending tubular wall (108) having a top ring groove (112) a minimal elevational distance TRH below the top surface (98), and an annular cooling recess (132) located beneath the top surface (98) and juxtaposed to the top ring groove (112) for removing heat away therefrom in use. The piston member (78) is preferably forged and subsequently machined to precisely controllable dimensions, and has a ratio of TRH to D of less than 0.06. Moreover, the piston assembly (76) is preferably of the articulated type and includes a forged aluminum piston skirt (80) connected to the piston member through a commmon wrist pin (82). The skirt has an upwardly facing oil trough that is disposed in a cooperating relationship with the cooling recess of the piston member. A midsupported cylinder liner (48) surrounds the piston assembly (76) and a recess is provided thereabout at an elevation aligned with the top ring groove (112) for maximizing cooling.
Abstract:
Present day diesel engines having aluminum piston assemblies are limited to combustion chamber pressures of approximately 12,410 kPa (1,800 psi) whereas the desire is to increase such pressures up to the 15,170 kPa (2,200 psi) range. To reach such levels the instant piston assembly (76) includes a steel piston member (78) having an upper cylindrical portion (96) of a diameter ''D'' and a compression height ''CH''. The ratio of the compression height ''CH'' to the diameter ''D'' being within the range of from 60 % to 45 %. The piston member (78) is preferably forged and subsequently machined to precisely controllable dimensions. Moreover, the piston assembly (78) is preferably of the articulated type and includes a forged aluminum piston skirt (80) connected to the piston member (78) through a common wrist pin (82). Engine manufacturers are also demanding a smaller engine package size while retaining power output, improve fuel consumption and decreased emissions. The subject piston member (76) provides a simple and inexpensive solution to the increased power output package size relationship. To insure a small engine package, the piston member (78) has a compression height to maximum diameter ratio within the range of from 60 % to 45 %. The piston member (78) is preferably made from a steel forging to insure a reduced porosity over that of existing standard castings.
Abstract:
PROBLEM TO BE SOLVED: To easily bond iron system metal and Cu alloy being a slide part with high bond strength.SOLUTION: In a method for manufacturing a slide member 10, 23 including a slide part 14, 54 respectively, iron system metal serving as a body part 13, 51 of the slide member 10, 23 and Cu alloy serving as a slide part 14, 54 and including at least one of Si and Al are bonded together in a solid phase by heat and pressurization by means of a discharge plasma sintering method.
Abstract:
A dry vacuum pump comprises a stator component and at least one rotor component. To improve the tolerance of the pump to corrosive gases passing through the pump, the stator component and/or said at least one rotor component are formed from silicon-molybdenum (SiMo) ductile iron.