Abstract: A bolt may be provided for a bolt carrier. The bolt carrier may comprise a gas inlet, a gas expansion chamber, a bolt bore, and the bolt. The gas expansion chamber that may receive a pressurized gas from the gas inlet. The bolt may be disposed in the bolt bore in the bolt carrier. The bolt may comprise a gas ring groove, a gas ring assembly disposed in the gas ring groove, and at least one gas port. The gas ring assembly may be adjacent to the bolt bore. The at least one gas port may provide a pathway for the pressurized gas from the gas expansion chamber to a volume underneath the gas ring assembly to increase a radial sealing force between the gas ring assembly and the bolt bore.

Abstract: A piston of an internal combustion engine may include a piston shaft and a piston head. The piston head may be provided with a closed cooling channel with a cooling medium arranged therein. The piston shaft may have a spherically round cross-sectional shape, wherein a deviation from the roundness with respect to a piston diameter may be less than 0.5 per thousand.

Abstract: A piston including a crown and at least one pin tower coupled to the crown. The pin tower has an opening therein configured to receive a pin therein along a pin axis. The piston further includes a skirt extending generally away from the crown, the skirt including a pair of opposed skirt panel portions. The skirt has a generally non-circular oval shape having a major axis extending generally parallel to the pin axis, wherein the panel portions are offset from the major axis.

Abstract: A piston of an internal combustion engine has a piston crown with annular grooves and a shaft part disposed on the piston crown. The shaft part has bearing shaft wall sections which are connected to one another via inclined connecting walls which are retracted with respect to the outer diameter of the piston. Piston-pin bosses for accommodating a piston pin are disposed in connecting walls. The connecting walls are retracted at such an angle that, in progressing from the lower edge over an intermediate region which lies further back than the lower edge, into an end region which lies further back than the intermediate region the connecting walls to over flush into a hub supporting region below the piston crown.

Abstract: A number of embodiments of a piston may have a shape that provides enhanced piston guidance. In such embodiments, the piston shape may include an axial profile that is configured to provide certain thrust load characteristics.

Abstract: A fluid metering system includes a housing having a piston chamber with first and second spaced ends, at least one housing inlet passage, and at least one housing outlet passage. The housing inlet and housing passages communicate with the piston chamber. A piston is disposed in the piston chamber for reciprocal movement between the first and second ends of the piston chamber to alternatingly define first and second volumes therein. At least one first slot, and at least one second slot are formed on the outer surface of the piston, and extend from respective ends of the piston toward the respectively opposite ends. The first slot has an opening that is in communication with the first volume, and the second slot has an opening in communication with the second volume.

Abstract: A reciprocating compressor is provided that includes a compression chamber inside of a cylinder and a piston inserted therein. The piston includes a head, a skirt extended from a lower end of the head so as to be spaced away from an inside wall of the cylinder, and guide surfaces extended from an outside surface of the skirt. Since the skirt is not in contact with the cylinder, a friction loss between the piston and the cylinder is reduced, and the guide surfaces assist the piston to make stable reciprocation. The head has a projection so as to be inserted into a discharge hole when the piston is at a top dead center. According to this, a dead volume formed when the piston is at the top dead center is reduced, thereby improving an efficiency of the compressor.

Abstract: A number of embodiments of a piston may have a shape that provides enhanced piston guidance. In such embodiments, the piston shape may include an axial profile that is configured to provide certain thrust load characteristics.

Abstract: The invention relates to a wear protection layer for piston rings in internal combustion engines consisting essentially of chromium carbides, wolfram carbide, chromium and nickel. The wear protection layer is formed from a mixture of powders in which the first powder consists of at least the alloy components chromium carbide, chromium and nickel, in the form of an agglomerated and sintered powder, and which has not been subjected to any secondary heat treatment that would make the powder brittle, such as plasma refinement, the carbides in the powder having an average diameter of essentially not more than 3 ?m. A second powder, also in the form of an agglomerated and sintered powder, contains wolfram carbide and is applied to at least one peripheral surface of the piston rings by thermal injection, so that two distinctive coating areas are produced in the wear protection layer. A first area, predominantly rich in chromium, and a second area, mainly rich in wolfram carbide are formed.

Abstract: The invention relates to a process for producing a cooling channel piston, in which the overall height is reduced in that the annular recess has a lower height than the height of the tool used for producing the cooling channel, and the production of the cooling channels starts parallel to the piston boss face, in which the axial height of the annular recess (8) is smaller than the axial height of the cooling channel (13).

Abstract: An object of the present invention is to effectively achieve the reduction in piston slap sound in both of an expansion stroke and a compression stroke in consideration of a difference between the behaviors of a piston in the expansion stroke and the compression stroke. For this purpose, in a piston P having a skirt 12 formed into an intermediately bulged barrel type, the axis L2 of a piston pin is offset with respect to the cylinder axis L1, and the decrement in radius of a lower skirt portion 20 is set to be large on a thrust side and small in an anti-thrust side. In the expansion stroke, the piston is positively swung, while the skirt 12 is put into abutment against a wall surface of a cylinder bore, thereby reducing the piston slap sound.

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 is free to slide in an engine cylinder, this piston comprising a piston head of circular cross-section, a skirt formed such that it is continuous with the lower part of said piston head, a piston pin passing through the skirt, and a connecting rod connected via this piston pin. This skirt comprises an upper part and a lower part which respectively have an elliptical horizontal cross-section with a short axis parallel to the piston pin, the horizontal cross-section of the upper part of the skirt having a higher eccentricity than that of the lower part of the skirt. The skirt further comprises a taper surface which smoothly connects its upper and lower parts. The contact surface between the skirt and the cylinder therefore has an inverted T shape so that the contact surface of the lower part of the skirt can be increased. It is therefore possible to set the distance from the center of the piston pin to the lower edge of the skirt such that it is no greater than 1.

Abstract: A piston for an internal combustion engine comprises at least a pair of ribs arranged between an inner surface portion of a skirt and side portions of pin bosses. The ribs are symmetrical with respect to a thrust center line of the piston and have in a longitudinal direction thereof a center line which is positioned to be lower than an axis of a piston pin.

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: A piston for connection by a piston pin and connecting rod to a crankshaft for reciprocating in a cylinder of an internal combustion engine. The piston has a crown and top land region, an intermediate region including at least one additional land, and a skirt region. Cross sections through the crown and top land region transverse to the cylinder axis are ovals whose major axes are generally parallel to the longitudinal axis of the piston pin. Cross sections through the intermediate region are either circular or oval, major axes of each of the ovals being generally transverse to the longitudinal axis of the piston pin.

Abstract: A piston for an internal combustion engine with a separate head and skirt which are joined by the piston pin. At least one of the upper lands has a reduced diametrical clearance with the cylinder wall in an area perpendicular to the pin direction. The bottom land has a reduced diametrical clearance with the cylinder wall in the pin direction. The lands are oval shaped, the bottom land optionally a truncated oval. At least one of the upper lands can have the shape of two ovals offset by 90.degree. like a cloverleaf.

Abstract: This invention relates to the shape of a skirt below the piston head of a piston in an engine cylinder and continuous with it. The skirt has a basic configuration comprising at least two type of elliptical horizontal cross-section with a short axis parallel to said piston pin, and a barrel-shaped vertical cross-section smaller at its top and bottom. A T-shaped projection is also provided on the lateral surfaces of the skirt corresponding to the two ends of the long axis of said ellipse, this projection consisting of a vertical piece and two side pieces situated on either side of the vertical piece. When the engine is running, the skirt comes into contact with the inner surface of the cylinder via this projection. The vertical section of the lower part of the skirt from below the lower edge of the two side pieces to the lower edge of the skirt is inclined toward the inside of said barrel-shaped vertical section so that the skirt is joined smoothly to the projection below the two side pieces.

Abstract: A piston with a skirt shaped to accommodate distortion by changing thermal and load conditions is further modified to increase stability and broaden load distribution to reduce contact forces and wear by providing maximum radii lines on either side of a longitudinal thrust plant with reduced radius regions forming apparent concavities therebetween.

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 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 second land has the largest diameter and exclusively guides the piston. The height of the second land is in the range of three to seven percent of the piston diameter. The diametrical second land clearance is 1.5% to 2.5%. The diametrical third land clearance is one percent of the piston diameter. The diametrical top land clearance is in the range of 1.5 mm to 2.0 mm.

Abstract: A piston for an internal combustion engine comprises a skirt portion formed with a piston pin hole. The skirt portion includes in an axial direction of the piston a first portion upper than an axis of the piston pin hole, and a second portion lower than the axis thereof. The first portion has a first cross section formed in accordance with a first ellipse, and the second portion has a second cross section formed in accordance with a second ellipse. The first and second ellipses have two foci, respectively, on a center plane of the piston which is perpendicular to the axis of the piston pin hole. The first ellipse is smaller in ellipticity than the second ellipse. The skirt portion including a ramp portion connecting the first portion to the second portion.

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 structure for an internal combustion engine is provided. This piston includes an oval slipper skirt with a cross sectional profile in the form of an ellipse defined by preselected major and minor axes. A difference between the major and minor axes is gradually increased nearing a lower edge of the skirt. The skirt distorts from an elliptical shape to a round shape when side thrust acts on thrust surfaces of the skirt to provide uniform contact with a cylinder wall.

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: 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: 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 includes a steel piston member having an upper cylindrical portion 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 is preferably forged and subsequently machined to precisely controllable dimensions. Moreover, the piston assembly is preferably of the articulated type and includes a forged aluminum piston skirt connected to the piston member through a common wrist pin. Engine manufacturers are also demanding a smaller engine package size while retaining power output, improve fuel consumption and decreased emissions.

Abstract: A piston comprises a piston crown section, a piston skirt section connected to the piston crown section and having a pair of relatively flat, inclined portions at a pair of radially opposite locations thereof and a pair of piston pin boss sections disposed through and connected to the inclined portions of the piston skirt section, respectively, with the distance between the inclined portions being decreased from the maximum at the upper portion of the piston skirt section to the minimum at the lower portion of the piston skirt section.

Abstract: Pistons are described having oval polar profiles or both oval polar profiles and axial profiles machined to asymmetric curvatures about the plane which includes both the piston axis and the minor axis over at least a part of the skirt length, the asymmetry of the polar profile comprising a greater convexity about the major axis on the thrust face over at least part of the axial length of the skirt region.

Abstract: A piston for an internal combustion engine in which the skirt portion of the piston is slightly oval rather than cylindrical and the size of the oval is varied along the skirt to produce contact surfaces of a particular shape engaging the cylinder. Specifically, the smallest diameter of the oval continuously increases from the piston rings downwardly and the largest diameter increases for a portion thereof. The contact surface shape has sloping sides to enhance the flow of lubricating oil away from the rings.

Abstract: A piston, particularly for internal combustion engines, of which the bearing surfaces with which the piston comes into contact with the engine cylinder bore lie on a generated surface which runs asymmetrically to the axis of an engine cylinder accommodating the piston without clearance in the longitudinal direction of the piston and/or in the circumferential direction.

Abstract: In a light alloy piston each of the load-carrying skirt surfaces is divided by a depression into two load-carrying partial shaft surfaces.In order to reduce the friction losses and the consumption of lubricant the depth of the depression (8, 9) between the tapered portions of the curved generatrix (7) at the top and bottom ends of the skirt is approximately twice the peak-to-valley height of the machined surface of the skirt (1). The load-carrying partial skirt surfaces (10, 11, 12, 13) and the depression (8, 9) are at least as wide as the wear pattern area, and the axial extent of the depression (8, 9) is so selected that the depression will not protrude from the cylinder when the piston is at its lower dead center and in the cold engine the load-carrying partial skirt surfaces (10, 11, 12, 13) have between the upper limit of the depression and the lower limit of the tapered portion of the curved generatrix (7) at top end of the skirt an axially parallel portion in a height of 1.5 to 4.5 mm, preferably 1.

Abstract: In a light alloy piston having a convex and oval external shape, the piston skirt has in the cold state a larger running clearance at its top end than at its bottom end. In order to reduce the friction loss of such piston, the piston skirt has a larger ovalness adjacent to the horizontal plane extending through the pin axis than in the remaining regions of the piston skirt.

Abstract: A fluid motor and more particularly a fluid motor having an improved piston head structure.