Patents by Inventor V. Durga N. Rao
V. Durga N. Rao has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6412453Abstract: A system for varying a compression ratio of an internal combustion engine includes: at least one sensor for measuring an operating condition of the internal combustion engine; a variable compression ratio apparatus for varying the effective length of a connecting rod, the compression ratio apparatus itself comprising a bearing retainer disposed between the connecting rod and a crank pin, the bearing retainer having an inner surface in communication with the crank pin and an outer surface in communication with the connecting rod, the connecting rod being axially movable relative to the bearing retainer along a longitudinal axis of the connecting rod to effect a selective displacement of the connecting rod relative to the bearing retainer, the displacement thereby causing a change in the effective length of the connecting rod and a desired compression ratio of the internal combustion engine; and an engine controller coupled to the internal combustion engine, the sensor and the variable compression ratio apparatType: GrantFiled: October 18, 2000Date of Patent: July 2, 2002Assignee: Ford Global Technologies, Inc.Inventors: V. Durga N. Rao, James Ryland Clarke, Mark Michael Madin, Yash Andrew Imai
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Patent number: 5629091Abstract: A collection of agglomerated anti-friction grains for plasma deposition, the grains each consisting essentially of (a) H.sub.2 O atomized stainless steel particles, (b) solid lubricant particles consisting of at least one of boron nitride or a eutectic of calcium fluoride and lithium fluoride, and (c) a binder holding said steel and solid lubricant particles together for plasma spraying, said binder being present in an amount of 0.5-4.0% by weight and is vaporizable at the temperature of plasma spraying and does not interfere with the deposited process.Type: GrantFiled: December 9, 1994Date of Patent: May 13, 1997Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Robert A. Rose, David A. Yeager, Carlo A. Fucinari
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Patent number: 5598763Abstract: A piston and ring assembly operative within a cylindrical bore wall to retain fluid to one side. The piston has a side wall for movement along the cylindrical wall and has one or more spaced grooves in the side wall, each groove defining a pair of interior groove surfaces spaced apart a uniform distance; at least one sealing element presenting a pair of opposed surfaces operating between and along the pair of groove surfaces, the sealing element being capable of engaging the cylindrical wall, the spacing between the opposed surfaces of the sealing element and the pair of interior surfaces of the groove being no greater than ten microns; and a solid film lubricant mixture coating the groove surfaces and the opposed surfaces of the sealing element, whereby surface adhesion of the fluid, present in the spacing, inhibiting migration of such fluid through the spacing and flutter of the sealing element, in said spacing, being essentially eliminated.Type: GrantFiled: March 14, 1994Date of Patent: February 4, 1997Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, David A. Yeager
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Patent number: 5554020Abstract: A high efficiency pump having relatively-moving parts constituted of a light weight material and a coating on at least one of the parts to effect essentially zero clearance between the parts where they merge together. The coating is comprised of solid lubricants in a polymer resin matrix stable up to 700.degree. F.Type: GrantFiled: October 7, 1994Date of Patent: September 10, 1996Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Carlo A. Fucinari
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Patent number: 5490445Abstract: A piston and ring assembly operative within a cylindrical bore wall to retain pressurized fluid to one side of the assembly, the piston having a crown and an annular side wall for movement along the bore wall.Type: GrantFiled: March 14, 1994Date of Patent: February 13, 1996Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, David A. Yeager
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Patent number: 5484662Abstract: A solid lubricant coating system for use with a metal interface subject to high temperatures and wet lubrication, comprising agglomerates of particles of (i) solid lubricant particles selected from the group consisting of graphite, boron nitride, molybdenum disulfide, lithium fluoride, NaF, WS.sub.2, and calcium fluoride; and (ii) steel particles fused together and bounding said solid lubricant particles at least at certain intersections, certain portions of said steel particles being air-hardened to a high hardness upon exposure of the coating to the interface at high temperatures.Type: GrantFiled: May 6, 1994Date of Patent: January 16, 1996Assignee: Ford Motor CompanyInventor: V. Durga N. Rao
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Patent number: 5482637Abstract: A composition of matter for depositing a thin anti-friction film that has a coefficient of friction of 0.06 or less. The composition comprises (a) a mixture of solid lubricant particles, a thermoset resin, and a catalyst for setting the resin, and (b) an evaporative medium for carrying the mixture during deposition. A solid film lubricant system for protecting metal wear interfaces subject to high temperatures and wet lubrications, comprising an oil-attracting solid lubricant mixture with at least two elements selected from the group of graphite, MoS.sub.2 and BN; a support for the mixture to loads of at least 10 psi at temperatures of 600.degree.-800.degree. F. while being thermally stable; a thermally stable thermoset polymer matrix, the polymer having inherent hydrocarbon chemical attraction to form a tenacious oil film of the lubricating oil on the wearing surface.Type: GrantFiled: August 31, 1994Date of Patent: January 9, 1996Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Daniel M. Kabat, Brian W. Lizotte
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Patent number: 5477820Abstract: Heat engine piston and combustion chamber construction enclosing a gas combustion zone, comprising: a piston body having a crown facing said gas combustion zone; combustion chamber surfaces cooperating with said piston to complete enclosure of said zone; and a thermal diffusivity coating on said crown and combustion chamber surfaces having an effective thickness to operate as a thermal diode to restrict heat transfer to said piston body and combustion chamber and to restrict heat transfer to said combustible charge prior to combustion.Type: GrantFiled: September 29, 1994Date of Patent: December 26, 1995Assignee: Ford Motor CompanyInventor: V. Durga N. Rao
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Patent number: 5469777Abstract: A piston assembly operable within a fluid bathed, cylinder wall, comprising a piston body (10) having at least one annular land (36) adapted to be in close-fitting relationship to the cylinder wall (37) an abradable coating (15) tenaciously adhered to said at least the one land (36) effective to create and sustain substantially zero clearance with the fluid bathed cylinder wall and a heat sink in the form of at least one of (i) heat conductors (23) in the coating to conduct heat from the land (36) and (ii) a piston body interior (52) effective to receive a heat conducting fluid (26) moving along the interior to extract heat therefrom. The abradable coating comprises solid lubricants at least two of which are selected from the group consisting of graphite, molydisulphide and boron nitride The heat conductors in the coating preferably consist of copper particles distributed throughout the coating and constitute at least 70-90% by weight of the abradable coating.Type: GrantFiled: July 5, 1994Date of Patent: November 28, 1995Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, James R. Clarke
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Patent number: 5464486Abstract: A method of making anti-friction coated surfaces subject to sliding wear, comprising: (a) forming grains of agglomerated solid lubricant particles and air-hardenable, fusable ingredients such as steel particles, the particles being agglomerated by a low melting medium such as wax; (b) providing a light metal-based component surface; (c) thermally spraying such grains onto said surface in a thickness range of 100-250 microns to form a coating substantially devoid of the low melting medium (the temperature of said thermal spraying liquifying and eliminating the wax by ash-free combustion); (d) removing at least a portion of the fusable particles by honing to expose edges of such particles; and (e) subjecting the exposed particles to air hardening (i.e., by available interfacing friction).Type: GrantFiled: May 9, 1994Date of Patent: November 7, 1995Assignee: Ford Motor CompanyInventor: V. Durga N. Rao
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Patent number: 5430938Abstract: Method of making a piston ring assembly by providing a metallic (i.e. cast aluminum) piston with a crown and an annular depending side wall; machining a stepped annular groove in the side wall having a total height of at least 4 mm (preferably having a combined total height equal to the groove height less 60 microns or less); fabricating a pair of metallic (i.e. aluminum based) split annular compression rings nestable within said groove and effective to operate together as a superimposed unit to seal against both said step and groove; coating said groove and the non-mating surfaces of said rings with solid film lubricants (i.e. graphite, BN and MoS.sub.2); and inserting said pair of coated rings into said coated groove with their split ends out of superimposed alignment.Type: GrantFiled: March 14, 1994Date of Patent: July 11, 1995Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Daniel M. Kabat
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Patent number: 5408964Abstract: An engine block with one or more anti-friction coated cylinder bores, comprising an oil-attracting coating of grains fused to each other and to the bore wall, the grains comprising agglomerates of solid lubricant particles and hardened, fused particles, the solid lubricant particles being selected from the group consisting of graphite molybdenum disulfide, boron nitride, lithium fluoride, and calcium fluoride, the coating having been finish-honed to expose certain margins of the fused particles.Type: GrantFiled: May 6, 1994Date of Patent: April 25, 1995Assignee: Ford Motor CompanyInventor: V. Durga N. Rao
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Patent number: 5406917Abstract: A valve assembly (10) for use in an engine (12), comprising a valve stem guide (14) and a valve seat insert (40) mounted within the engine (12), the valve stem guide (14) and the valve seat insert (40) being provided with a solid film lubricant (30) impregnated therewithin. A valve (20) is reciprocatingly received within the internal bore (16) of the tubular valve stem guide (14). The valve (20) includes an axially extending valve stem (22) which is received by the solid film lubricant (30) within the valve stem guide (14), thereby reducing friction therebetween. The valve stem (22) and the valve stem guide (14) are formed so as to cooperate with associated components within narrowly defined dimensional tolerances in a manner which has the characteristics of reduced friction and lessened passage of oil to the exhaust system of the engine (12). The valve guide assembly (10) thus has the characteristic of being operable in an oil-starved state.Type: GrantFiled: December 15, 1993Date of Patent: April 18, 1995Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Gary M. Crosbie
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Patent number: 5392692Abstract: A piston and ring assembly operative within a cylindrical bore wall to retain fluid to one side of the assembly, comprising a piston having at least one annular stepped groove in the side wall of the piston, the groove being stepped into uppermost and lowermost spaces with the uppermost space having the greatest depth; at least two split compression rings in the groove, effective to each substantially annularly engage the bore wall, the rings having mating surfaces superimposed one upon another and having their split ends out of superimposed alignment, and a solid lubricant that coats essentially all of the groove and constitutes the non-mating surfaces of the superimposed rings. Pressure of the retained fluid forces the rings together to act in unison and seal jointly against both the step and a side of the groove opposite the retained fluid.Type: GrantFiled: March 14, 1994Date of Patent: February 28, 1995Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Daniel M. Kabat
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Patent number: 5363821Abstract: A solid film lubricant system for protecting metal wear interfaces subject to high temperatures and wet lubrications, comprising an oil-attracting solid lubricant mixture with at least two elements selected from the group of graphite, MoS.sub.2 and BN; a support (i.e., hard lands or hard sublayer) for the mixture to loads of at least 10 psi at temperatures of 600.degree.-800.degree. F. while being thermally stable; a thermally stable thermoset polymer matrix adhering the mixture to the support or the wear surface, the polymer having inherent hydrocarbon chemical attraction to form a tenacious oil film of the lubricating oil on the wearing surface. A method of making anti-friction coated surfaces comprising providing a light metal based cylinder surface (i.e.Type: GrantFiled: July 6, 1993Date of Patent: November 15, 1994Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Daniel M. Kabat, Brian M. Lizotte
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Patent number: 5358753Abstract: A method of making an anti-friction coating on a metal surface subject to sliding wear, including the steps of: forming an encapsulated powder having grains made of a core of solid lubricants including at least graphite and MoS.sub.2 (others may include BN, NaF, LiF, CaF.sub.2, and WS.sub.2), and a thin shell of fusable soft metal such as Ni, Co, Fe, Zn, Sn, Mg, or Cu; plasma spraying the powder onto a light metal surface, such as a cylinder bore wall of an internal combustion engine, to form a coating; and finish-smoothing the coating to a uniform thickness of about 25-175 microns. Some core particles may be hard, wear-resistant particles such as SiC, NiCrAl, FeMn, FeCrAl, FeWNiVCr, NiCrMoVW, FeCrMoWV, CoFeNiCrMoWV, NiCrMoV, and CoMoCrVW.Type: GrantFiled: September 24, 1993Date of Patent: October 25, 1994Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Daniel M. Kabat, Robert A. Rose
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Patent number: 5332422Abstract: A plasma sprayable powder for coating surfaces such as cylinder bores of an internal combustion engine, comprising grain size agglomerates of (i) a plurality of solid lubricant particles selected from the group consisting of graphite, MoS.sub.2, BN, CaF.sub.2, and LiF; and (ii) fusable ingredients adjacent the solid lubricant particles, the ingredients being air-hardenable upon friction-promoting-use, and the lubricants and fusable ingredients being agglomerated together by a low melting medium in the grains.A solid lubricant coating system for use with a metal interface subject to high temperatures and wet lubrication, comprising agglomerates of particles of (i) solid lubricant particles selected from the group consisting of graphite, boron nitride, molybdenum disulfide, lithium fluoride, NaF, WS.sub.Type: GrantFiled: July 6, 1993Date of Patent: July 26, 1994Assignee: Ford Motor CompanyInventor: V. Durga N. Rao
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Patent number: 5315970Abstract: An engine block having one or more anti-friction coated cylinder bore walls, comprising: a coating of grains fused to the cylinder bore wall, the grains being comprised of solid lubricant particles encapsulated within a soft metal shell, the shells being fused together to form a network with limited porosity, the solid lubricant comprising at least graphite and MoS.sub.2 ; and wet oil lubrication retained within the porosity of the coating.Type: GrantFiled: September 24, 1993Date of Patent: May 31, 1994Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Daniel M. Kabat, Robert A. Rose
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Patent number: 5302450Abstract: A thermally sprayable powder having grains comprising: a core of solid lubricant particles comprised of at least graphite and MoS.sub.2 (others may include Bn, NaF, LiF, CaF.sub.2, and WS.sub.2); and a thin, soft metal shell (Ni, Co, Fe, Zn, Sn, Mg, or Cu) encapsulating such core. Some core particles may also be hard, wear-resistant particles from the group consisting of SiC, NiCrAl, FeMn, FeCrAl, FeWNiVCr, NiCrMoVW, FeCrMoWV, CoFeNiCrMoWV, NiCrMoV, and CoMoCrVW.Type: GrantFiled: July 6, 1993Date of Patent: April 12, 1994Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Daniel M. Kabat, Robert A. Rose
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Patent number: 5295461Abstract: A valve assembly (10) for use in an engine (12), comprising a valve stem guide (14) and a valve seat insert (40) mounted within the engine (12), the valve stem guide (14) and the valve seat insert (40) being provided with a solid film lubricant (30) impregnated therewithin. A valve (20) is reciprocatingly received within the internal bore (16) of the tubular valve stem guide (14). The valve (20) includes an axially extending valve stem (22) which is received by the solid film lubricant (30) within the valve stem guide (14), thereby reducing friction therebetween. The valve stem (22) and the valve stem guide (14) are formed so as to cooperate with associated components within narrowly defined dimensional tolerances in a manner which has the characteristics of reduced friction and lessened passage of oil to the exhaust system of the engine (12). The valve guide assembly (10) thus has the characteristic of being operable in an oil-starved state.Type: GrantFiled: April 13, 1992Date of Patent: March 22, 1994Assignee: Ford Motor CompanyInventors: V. Durga N. Rao, Gary M. Crosbie