Abstract: An example embodiment of an all-stroke-variable internal combustion engine may include a piston slidably positioned within an engine cylinder for asymmetrical reciprocation and a primary crankshaft and a half-speed crankshaft to be operatively engaged for rotation of the half-speed crankshaft at half of a speed of the primary crankshaft, wherein the rotation of the half-speed crankshaft at half of the speed of the primary crankshaft to result in the asymmetrical reciprocation of the piston so as to produce a stroke length that is independently variable over four distinct strokes of a full cycle of the all-stroke-variable internal combustion engine.

Abstract: A poppet valve, in particular a hollow poppet valve, includes: a valve stem; a valve body having along a longitudinal axis, a first end with a neck portion to which the valve stem is coaxially arranged and having along a longitudinal axis a second end with a first conical contact face portion, the valve body including a cavity with a first opening towards the first end and a second opening towards the second end; and a valve cap coaxially arranged to the valve body on the second end for closing the second opening, the valve cap having a second conical contact face portion to form together with the first conical contact face portion a valve head contact face.

Abstract: A poppet valve (2) with a valve body (4) has a cavity (6), a coolant inlet port (8). A coolant outlet port (10). The coolant inlet port (8) and the coolant outlet port (10) are arranged on a valve stem (12) of the poppet valve (2). The cavity (6) extends into the valve stem (12) of the poppet valve (2) and into a valve head (14) of the poppet valve (2), wherein there is provided a coolant conducting element (16) within the cavity (6) and extending into the cavity (6) from the valve head (14) to the valve stem (12), where the coolant conducting element (16) in each case has a cross-section. The coolant conducting element (16) includes a pipe section (18) and a funnel section (20), and the coolant conducting element (16) extends concentrically to the poppet valve (2) in the cavity (6) of the poppet valve (2).

Abstract: A thermally compensated bore guide system for a shaft, the shaft configured to translate along a longitudinal axis, is provided. The thermally compensated bore guide system includes an inner bore defined within a component. The inner bore is configured to circumferentially surround at least a portion of the shaft, wherein the inner bore is non-linear in response to the thermally compensated bore guide system being at a first thermal condition and wherein the inner bore is configured to be linear and to define a bore axis substantially aligned with the longitudinal axis in response to the thermally compensated bore guide system being at a second thermal condition.

Abstract: A valve for an internal-combustion engine may include a body. The body may include a titanium alloy. At least one region of the body may include a nitrided layer. The nitrided layer may include at least one of titanium nitrides and aluminium-titanium nitrides.

Abstract: A poppet valve has an elongated stem that is configured to extend along a longitudinal axis. The poppet valve further includes a valve body that is disposed laterally with respect to the longitudinal axis and located in a spaced apart relation with an end of the elongated stem. The valve body has a pair of opposing faces disposed co-axial with the longitudinal axis of the elongated stem. The poppet valve also includes at least two arcuately shaped appendages depending downwardly from the end of the elongated stem and extending away from the longitudinal axis of the elongated stem. An end of each appendage is disposed in abutment with an annular region defined on one of the opposing faces of the valve body, a perimeter of the annular region being larger than a perimeter of the elongated stem measured about the longitudinal axis.

Abstract: A tribological system may include a valve seat ring composed of a sintered material and a valve having a surface at least in a seat region that may be at least one of (i) untreated, (ii) hardened, and (iii) plated. The sintered material may be a pressed and sintered powder mixture having a composition that may include (i) 5 to 45 wt % of at least one Fe-based hard phase, (ii) 0 to 2 wt % of each of graphite particles, MnS powder, MoS2 powder, and FeP powder, (iii) 0 to 7 wt % copper powder and 0 to 4 wt % Co powder, (iv) 0.1 to 1.0 wt % of a pressing aid, (v) a high-speed steel having a composition including 14-18 wt % Cr, 1.2-1.9 wt % C, 0.1-0.9 wt % Si, 0.5-2.5 wt % of each of V, W, and Mo, and (vi) a balance of Fe and production-related impurities in quantities of <1.5 wt %.

Abstract: A valve seat insert for an internal combustion engine has a first portion that is adapted to contact a cylinder head and a second portion that is adapted to contact a valve. The valve seat insert has a valve seat insert volume. A major part of the valve seat insert volume includes a homogeneous material that includes nitrides.

Abstract: A manufacturing method for an engine includes: preparing, as a preparing step, a cylinder head having a surface on which a ceiling surface of a combustion chamber is formed; forming, as a film formation step, a thermal insulation film on the ceiling surface; measuring, as a measurement step, a volume of the thermal insulation film; and selecting, as a selection step, a rank for an engine valve to be used in combination with the ceiling surface so as to correspond to an amount of difference of a measured volume of the thermal insulation film from a designed value of a volume of the thermal insulation film, the rank being selected from a plurality of ranks set in correspondence with thicknesses of umbrella portions of engine valves.

Abstract: An intake valve for a combustion engine is described. The intake valve has a head portion that is designed to improve the flow of air-fuel mixture around the head portion and into the combustion chamber. The head portion has a beveled or rounded edge at the top surface. The angle changes from the underside surface to the top surface are rounded to prevent separation of the air-fuel mixture from the surface of the intake valve. In addition, the underside surface of the head portion has a plurality of helical grooves that induce a circular flow to improve mixing of the air-fuel mixture in the chamber. The helical grooves also improve heat exchange between the air-fuel mixture and the intake valve.

Abstract: A conductor assembly includes a first conductor made of metal and a second conductor bonded to the first conductor. The second conductor is made of a metal plate having first and second surfaces opposite to each other. The second conductor has a projection locally projecting from the first surface. A recess is provided in the second surface of the second conductor opposite to the projection. The projection of the second conductor has a portion contacting and entering into the first conductor. The projection of the second conductor is resistance-welded to the first conductor. The portion of the projection of the second conductor has two tips locally projecting from the portion of the projection of the second conductor and entering the first conductor.

Abstract: An engine valve and a method of producing the engine valve are provided. The engine valve includes a shaft part and an umbrella part formed at one end of the shaft part. The engine valve opens and closes an intake port or an exhaust port of a combustion chamber of an internal combustion engine. Further, at least a portion of the engine valve that extends from the umbrella part to a position on the shaft part in a longitudinal direction thereof includes a valve body made of steel or nickel alloy, and a core member made of copper or copper alloy and provided inside the valve body.

Abstract: A precision forming method of a high-efficiency and near-net hollow valve blank of an engine is provided, wherein the precision performing is realized by the cross wedge rolling mold, under the rolling the metal tubing for the valve deforms, with a middle part sunken and two ends elongating, the middle part forms a stem part of a hollow valve, the two ends form disk parts to be machined, and the connection sections between the disk parts and the stem part form neck parts having arced concave faces and a frustoconical lateral face in structure, achieving better consistency among the acquired hollow valve blanks. The disk part of each acquired hollow valve preformed blank is machined by the die-forging forming mold that is matched with the disk structure of the manufactured hollow valve, the hollow valve preformed blank is directly placed in the cavities of the die-forging forming mold for forging.

Abstract: A galleryless steel piston designed to improve thermal efficiency, fuel consumption, and performance of an engine is provided. The piston includes a steel body portion and a thermal barrier layer applied to an upper combustion surface and/or a ring belt to reduce the amount of heat transferred from a combustion chamber to the body portion. The thermal barrier layer has a thermal conductivity which is lower than a thermal conductivity of the steel body portion. The thermal barrier layer typically includes a ceramic material, for example ceria, ceria stabilized zirconia, and/or a mixture of ceria stabilized zirconia and yttria stabilized zirconia in an amount of 90 to 100 wt. %, based on the total weight of the ceramic material. The thermal barrier layer can also have a gradient structure which gradually transitions from 100 wt. % of a metal bond material to 100 wt. % of the ceramic material.

Abstract: An iron-based alloy includes, in weight percent, carbon from about 2 to about 3 percent; manganese from about 0.1 to about 0.4 percent; silicon from about 0.3 to about 0.8 percent; chromium from about 11.5 to about 14.5 percent; nickel from about 0.05 to about 0.6 percent; vanadium from about 0.8 to about 2.2 percent; molybdenum from about 4 to about 7 percent; tungsten from about 3 to about 5 percent; niobium from about 1 to about 3 percent; cobalt from about 3 to about 5 percent; boron from zero to about 0.2 percent; and the balance containing iron and incidental impurities. The alloy is suitable for use in elevated temperature applications such as in valve seat inserts for combustion engines.

Abstract: An engine cylinder head includes an internal metal structure formed from a metal material, at least a portion of which includes a thermal coating and an external polymer composite structure formed from a polymer composite material, wherein the external polymer composite structure at least partially surrounds the internal metal structure.

Abstract: A valve for a valve device may include a valve stem, which in an axial direction relative to a valve stem axis merges into a valve disc projecting from the valve stem radially. A valve cap may be included composed of a metal. The valve cap may be attached to an axial end portion of the valve stem facing away from the valve disc. The valve cap may cover a face end of the valve stem facing away from the valve disc and may envelope the axial end portion of the valve stem at least partially.

Abstract: A system for an internal combustion engine can include a separation device and an engine component including first and second valves. The separation device can separate intake air into a volume of nitrogen-rich air and a volume of oxygen-rich air. A first valve element can be movable relative to a first valve body and can have an annular shape disposed about a central axis of the combustion chamber. The first valve body can be fluidly coupled to the separation device and direct the oxygen-rich air into a central area of the combustion chamber. A second valve element can be movable relative to a second valve body and can have an annular shape disposed about the central axis, radially outward of the first valve. The second valve body can be fluidly coupled to the separation device and can direct the nitrogen-rich air to a peripheral area of the combustion chamber.

Abstract: A spray coating film has a first spray coating film formed on a surface of an aluminum substrate and a second spray coating film formed on a surface of the first spray coating film. In the first spray coating film, an inorganic material with a layered crystalline structure is dispersed in a Ni-based alloy material, and an area ratio of the inorganic material is in a range from 40% to 80% relative to the sectional area of the first spray coating film. The second spray coating film is a porous film composed of ZrO2—SiO2 based ceramic containing 30% to 50% by mass of SiO2, and the second spray coating film has an area ratio of pores of 30% to 80% relative to the sectional area of the second spray coating film.

Abstract: With a poppet valve using a coolant, maximum combustion efficiency is realized by adjusting relative values of a heat insulation effect and a heat dissipation effect. From the inside of a head portion (14) to a stem portion (12) of a hollow poppet valve (10) a heat insulating space (S1) and a cooling portion (S2) loaded with a coolant (19), separated from each other by a partition (15), are formed. By properly setting an installation position and a vertical length of the partition (15) according to a type of vehicle for which the valve is used, appropriate heat insulation effect and heat dissipation effect are obtained. Further, by the partition (15), mechanical or thermal strength of the poppet valve in which the heat insulating space (S1) and the cooling portion (S2) are formed is increased.

Abstract: An Fe—Ni—Cr alloy is composed essentially of, in terms of wt. %: 2.4 to 3.7 Al, up to 1.05 Co, 14.8 to 15.9 Cr, 25 to 36 Fe, up to 1.2 Hf, up to 4 Mn, up to 0.6 Mo, up to 2.2 Nb, up to 1.05 Ta, 1.9 to 3.6 Ti, up to 0.08 W, up to 0.03 Zr, 0.18 to 0.27 C, up to 0.0015 N, balance Ni, wherein, in terms of atomic percent: 8.5?Al+Ti+Zr+Hf+Ta?11.5, 0.53?Al÷(Al+Ti+Zr+Hf+Ta)?0.65, and 0.16?Cr÷(Fe+Ni+Cr+Mn)?0.21, the alloy being essentially free of Cu, Si, and V.

Abstract: A cylinder head of an internal combustion engine may include an opening and a sensor sleeve. The opening may extend through the cylinder head. The sensor sleeve may be shrink fitted in the opening. The sensor sleeve may be configured to receive a sensor. The sensor may be mounted within the sensor sleeve through a mounting mechanism.

Abstract: A valve for use in an internal combustion engine is disclosed. The valve includes a stem friction welded to a head portion. The head portion is cast from a single crystal metal using a casting process that creates little or no grain boundaries. The single crystal metal can be a nickel based superalloys such as CMSX-4, CMSX 3, Rene N5, and Rene N6. By having little or no grain boundaries, defects that occur in other types of casting material, such as large numbers of grain boundaries can be minimized. This allows the head portion and particularly the combustion face to withstand an operating temperature in the combustion chamber in excess of 850° C.

Abstract: The valve seat includes an iron-based sintered alloy subjected to oxidation treatment, which is obtained by subjecting an iron-based sintered alloy including: 4 mass % to 15 mass % of Co particles; and hard particles each containing at least one compound of an intermetallic compound, a carbide, a silicide, a nitride, or a boride that has one or more kinds of elements selected from group 4a to 6a elements in a periodic table, and having a hardness of from 600 HV to 1,600 HV to oxidation treatment, and which has an oxide mainly including triiron tetraoxide (Fe3O4) and cobalt oxide (CoO) formed on a surface and in an interior of the iron-based sintered alloy. The iron-based sintered alloy subjected to oxidation treatment has an area ratio of the oxide of from 5% to 25% in a cross section thereof in a state prior to installation on the cylinder head.

Abstract: A hardfacing material includes a metal matrix material and particles of crushed polycrystalline diamond material embedded within the metal matrix material. An earth-boring tool includes a body comprising particles of fragmented polycrystalline diamond material embedded within a metal matrix material. The particles of fragmented polycrystalline diamond material include a plurality of inter-bonded diamond grains. A method includes forming an earth-boring tool including a metal matrix material and particles of crushed polycrystalline diamond material.

Abstract: A valve for a valve device may include a valve stem, which in an axial direction relative to a valve stem axis merges into a valve disc projecting from the valve stem radially. A valve cap may be included composed of a metal. The valve cap may be attached to an axial end portion of the valve stem facing away from the valve disc. The valve cap may cover a face end of the valve stem facing away from the valve disc and may envelope the axial end portion of the valve stem at least partially.

Abstract: A valve for an engine cylinder includes a head. The valve is selectively moveable between a closed position in which the head blocks a port and an open position in which the head unblocks the port. A lower stem is formed as one-piece with the head, and a thermal cavity formed within the lower stem. The thermal cavity is at least partially filled with a heat transfer medium. An upper stem is attached to the lower stem opposite the head. A thermal barrier is located adjacent a junction of the lower stem and the upper stem.

Abstract: The present disclosure relates to an engine valve device including: engine valves; valve guides configured to guide a reciprocating motion of the engine valves; and stem seals fitting on one end of each of the valve guides and circumferentially covering the engine valves, in which the engine valves have micro-machined oil ports on the surfaces surrounded by the valve guides or the stem seals.

Abstract: A heat transferring engine valve for an internal combustion engine to increase the combustion efficiency and fuel economy of the engine. The heat transferring valve includes a valve head and a heat transferring member situated at the combustion surface of the valve head and extending toward the combustion chamber. The heat transferring member absorbs heat of combustion during the power stroke of an engine cycle and releases the heat into the combustion chamber during the compression stroke of a succeeding engine cycle, thereby raising the temperature of fuel at the start of combustion. A method for increasing the efficiency of combustion in an internal combustion engine by incorporating at least one heat transferring valve into the engine.

Abstract: A method for producing a hollow valve of an internal combustion engine may include providing a hollow valve stem, a valve cone, and a valve bottom; pushing the valve cone over the valve stem via a press fit, wherein the valve cone includes an outer surface transitioning to the valve stem to define a testing surface; and welding the valve cone to the valve stem via at least one of a laser beam and an electron beam, wherein the welding occurs such that no melting of the outer surface in the region of the testing surface of the valve cone occurs.

Abstract: A valve for use in an internal combustion engine is disclosed. The valve includes a stem connected to a fillet disposed between the stem and a seat face. A port receives the stem and accommodates a seat insert that engages the seat face when the valve is in a closed position. The seat insert is fabricated from a non-cobalt-based alloy or an iron-based alloy and the seat face is coated with a cobalt-based alloy or a nickel-based alloy. The coating may be applied using a thermal spray process, such as HVOF.

Abstract: An intake valve of an internal combustion engine includes a valve body and a valve stem extending from a central portion of the valve body. The valve body includes a valve body framework portion and a valve body thick portion provided on an outer side of the valve body framework portion. The valve body framework portion and the valve stem are made of iron material and the valve body thick portion is made of aluminum alloy.

Abstract: A method for producing a hollow engine valve is disclosed which involves gradually reducing the size of the outer diameter and inner diameter of a hollow shaft of a semi-finished product sequentially inserting the hollow shaft into a plurality of molding holes having different hole shapes so as to gradually extend the length of the hollow shaft, and forming the hollow shaft into a predetermined shape by sequentially performing a drawing process. The semi-finished product is subjected to heat treatment such that the hardness thereof is equal to or less than a predetermined hardness, and the maximum thickness between the hollow shaft and an umbrella portion connected to the bottom edge of the hollow shaft is formed to be thicker than the thickness of the hollow shaft by means of a molding hole of a die which is adjusted to have a specific length and maximum inner diameter.

Abstract: For reducing the NOx-emission of a large sized two stroke diesel engine having at least one combustion room (3), a reciprocating piston (4) and an exhaust opening (12) controlled by an exhaust valve (13) at each work cyclus a small volume of burnt gas is retained in the combustion room (3) and so added to the fresh air for the next combustion. For achieving this retention of burnt gas the underside of the valve disc (15) off the exhaust valve (13) is provided with a shallow concave face (17) building a basin-like collection room, whose depth is within a range of 2-10% of the outer diameter of the valve disc (15).

Abstract: The present invention provides a valve for an engine and a method for treating the surface thereof. The valve for the engine includes a buffer layer, an intermediate layer, a TiAlN/CrN first nanostructured multilayer, and a TiAlCN/CrCN second nanostructured multilayer. The buffer layer is coated over a surface of a stem part as a lowermost layer and is formed of Ti or Cr. The intermediate layer is coated over the buffer layer and is formed of CrN, TiN, or TiCN. The TiAlN/CrN first nanostructured multilayer is coated over the intermediate layer. The TiAlCN/CrCN second nanostructured multilayer is coated over the TiAlN/CrN first nanostructured multilayer as an uppermost layer.

Abstract: A movable wall member, in form of an exhaust valve spindle (1) or a piston (7) for an internal combustion engine, comprises a base portion (17, 20) of an alloyed steel having a carbon-content in the range from 0.15 to 0.35% by weight, and an outer portion (14, 5) forming the surface of the wall member facing a combustion chamber. The outer portion is of a hot-corrosion-resistant alloy, which is nickel-based, chromium-based or cobalt-based. At least one buffer layer (18, 21) of an alloy is located in between the base portion and the outer portion. The alloy of the buffer layer is different from the alloyed steel of the base portion and different from the hot-corrosion-resistant alloy of the outer portion. The alloy of the buffer layer comprises from 0% to at the most 0.09% C in percent by weight of the buffer layer, and that the buffer layer has a thickness of at least 1.5 mm.

Abstract: A moveable valve sealing body, especially a valve sealing body of a gas exchange valve of an internal combustion engine, exposed to hot gases and comprising a sealing area that can be applied to a valve seat ring, enabling good heat dissipation outside an oil-lubricated guiding means connected to the sealing body. For this purpose, such a sealing body is characterized in that at least one surface region of the sealing body, which region being exposed to the hot gases, up to maximally directly on the sealing region of this sealing body, is composed respectively of at least one first and one second material (1, 2), wherein the second material (2) overlaps the first material (1) in an externally heat-conducting manner and furthermore has a greater heat conductivity than the first material (1). The second material (2) is applied by means of a thermal spraying method.

Abstract: Disclosed is a method—for producing an engine valve (V) filled with metallic sodium (Na) within by means of: forming a stem section (S), which has a hollow section (H), at an intended size by successively drawing the stem section (S) using dies (D1, D2, Dx, Dx+1, Dn) in a manner so as to causing the size of the outer diameter and the inner diameter of the stem section (S) to contact in a stepwise fashion; and inserting metallic sodium (Na) into the hollow section (H) of the stem section (S)—wherein after drawing the stem section (S) until the inner diameter of the hollow section (H) of the stem section (S) has become a prescribed size (steps S11-S15) and then inserting the block-shaped solid metallic sodium (Na) into the hollow section (H) of the stem section (S) (step S16), the stem section (S) is further drawn (steps S17 and S18).

Abstract: A forged exhaust poppet valve and a method of solution heat treating the same are provided. The forged exhaust poppet valve (10) includes a head portion (12) which has a seat portion (14) on the outer periphery thereof and is integral with a diametrically tapered neck portion (16) connected to a stem portion (18). Using a radio-frequency heating apparatus, a solution heat treatment is given to a predetermined transitional region (A) of the neck portion and the stem portion that is exposed to exhaust air during a valve opening period such that the grain size in the region (A) does not exceed ASTM 10, thereby securing a necessary high-temperature creep strength in the region (A) and a necessary hardness (wear resistance) in the seat portion (14) and thereby rendering the exhaust poppet valve highly durable.

Abstract: A semi-finished product having a hollow and an expansion diameter portion is manufactured in advance (first step), and a press device for folding an outer cylinder (4) and an inner cylinder (5) around an entire die set (DS) is used, thereby performing drawing with a body of the semi-finished product as the center in a constant temperature atmosphere at any temperature between a room temperature and 870° C. (second step).

Abstract: A heat transferring engine valve for an internal combustion engine to increase the combustion efficiency and fuel economy of the engine. The heat transferring valve includes a valve head and a heat transferring member situated at the combustion surface of the valve head and extending toward the combustion chamber. The heat transferring member absorbs heat of combustion during the power stroke of an engine cycle and releases the heat into the combustion chamber during the compression stroke of a succeeding engine cycle, thereby raising the temperature of fuel at the start of combustion. A method for increasing the efficiency of combustion in an internal combustion engine by incorporating at least one heat transferring valve into the engine.

Abstract: A tappet for a valve train or a pump drive particularly a cup tappet (1) having a hollow cylindrical outer body on whose wall region (4) an anti-rotation element (9) is received in a window-type through-opening (15), the anti-rotation element (9) being seated through support surfaces (12, 13) of a head (10) on an outer diameter (14) of the wall region (4) and extending with a shank (11) projecting from the head (10) through said through-opening (15). The anti-rotation element (9) is fixed via a welded joint. In order to fix the anti-rotation element (9) with low manufacturing costs and, at the same time, with only an insignificant impairment of the outer body, the welded joint is made between the shank of the anti-rotation element (9) and an inner body that is received in the outer body and is connected to the outer body. A method of making a tappet of the aforesaid tappet is also provided.

Abstract: An intake engine valve may have a tapered portion positioned between a valve head and a valve stem tapering from a larger size to a smaller size in the direction of the valve stem. The valve stem may include a small diameter portion positioned between a guide stem portion And a stem end portion on the side of the tapered portion and having a diameter smaller than a diameter or diameters of the guide stem portion and the stem end portion. The guide stem portion may be guided by a valve guide of the engine.

Abstract: A surface hardening material being excellent in impact resistance and having abrasion resistance is provided. Provided are: a high-toughness cobalt-based alloy containing 25.0 to 40.0 mass % of Cr, 0.5 to 12.0 mass % of a sum of W and/or Mo, 0.8 to 5.5 mass % of Si, and 0.5 to 2.5 mass % of B, 8.0 mass % or less of each of Fe, Ni, Mn, and Cu, and 0.3 mass % or less of C, the sum amount of Fe, Ni, Mn, and C being 10.0 mass % or less, and the remainder comprising 48.0 to 68.0 mass % of Co and unavoidable impurities; and an engine valve coated with the same.

Abstract: A valve seat of an iron-based sintered alloy having high wear resistance in a wide temperature range, which can be used in direct injection engines with improved fuel efficiency, low emission and high power, is obtained by limiting the amount of a solid lubricant dispersed in the matrix of the valve seat of an iron-based sintered alloy, and dispersing at least two types of hard particles having different hardnesses in the matrix, thereby providing high strength and self-lubrication, as well as improved wear resistance under no lubrication in a wide temperature range.

Abstract: A valve for an engine cylinder includes a head. The valve is selectively moveable between a closed position in which the head blocks a port and an open position in which the head unblocks the port. A lower stem is formed as one-piece with the head, and a thermal cavity formed within the lower stem. The thermal cavity is at least partially filled with a heat transfer medium. An upper stem is attached to the lower stem opposite the head. A thermal barrier is located adjacent a junction of the lower stem and the upper stem.

Abstract: Provided is a method for producing an engine valve by subjecting a stem portion having a hollow part to a drawing treatment using a series of dies such that the outer diameter and inner diameter of the stem portion become smaller in steps and the stem portion is thereby molded to the desired size, whereby, after the stem portion has been subjected to the drawing treatment until the inner diameter of the hollow part of the stem portion has reached a specific size, sodium metal in the form of a solid block is introduced to the hollow part of the stem portion, and a protective agent made from solid paraffin or naphthalene is also introduced to the hollow part of the stem portion such as to form a barrier between the sodium metal and the atmosphere, after which the stem portion is further subjected to a cold drawing treatment.

Abstract: A valve system for controlling the charge exchange in an internal combustion engine may include a valve seat ring and a valve having a valve seat configured to form a sealing system with the valve seat ring, wherein the valve seat may be nitrocarburised.

Abstract: The present invention provides a valve for an engine and a method for treating the surface thereof. The valve for the engine includes a buffer layer, an intermediate layer, a TiAlN/CrN first nanostructured multilayer, and a TiAlCN/CrCN second nanostructured multilayer. The buffer layer is coated over a surface of a stem part as a lowermost layer and is formed of Ti or Cr. The intermediate layer is coated over the buffer layer and is formed of CrN, TiN, or TiCN. The TiAlN/CrN first nanostructured multilayer is coated over the intermediate layer. The TiAlCN/CrCN second nanostructured multilayer is coated over the TiAlN/CrN first nanostructured multilayer as an uppermost layer.

Abstract: A chromium-iron alloy comprises in weight %, 1 to 3% C, 1 to 3% Si, up to 3% Ni, 25 to 35% Cr, 1.5 to 3% Mo, up to 2% W, 2.0 to 4.0% Nb, up to 3.0% V, up to 3.0% Ta, up to 1.2% B, up to 1% Mn and 43 to 64% Fe. In a preferred embodiment, the chromium-iron alloy comprises in weight %, 1.5 to 2.3% C, 1.6 to 2.3% Si, 0.2 to 2.2% Ni, 27 to 34% Cr, 1.7 to 2.5% Mo, 0.04 to 2% W, 2.2 to 3.6% Nb, up to 1% V, up to 3.0% Ta, up to 0.7% B, 0.1 to 0.6% Mn and 43 to 64% Fe. The chromium-iron alloy is useful for valve seat inserts for internal combustion engines such as diesel or natural gas engines.