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 cooled piston plunger for internal combustion engines having a separable piston head and piston shaft, wherein cooling oil is injected into an outer annular space in the piston head and distributed by oil collecting pockets of different sizes arranged in opposite relationship within the annular space at the upper end of the piston shaft to thereby uniformly distribute the desired cooling effect around the circumference of the piston head.

Abstract: In a two-piece piston with a head piece and a trunk hinged only over the piston pin, the annular space radially located inside the piston ring groove and open in the direction of the trunk is covered with a sheet metal wall part forming a cooling duct. The sheet metal wall part is held by a collar that extends from the outer annular wall of the head piece and is cramped around the sheet metal wall part. For optimally covering the annular space, the sheet metal wall part is radially divided into two parts.

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: The external profile of a piston rod employed in the engines of passenger cars ensures smoother piston travel on start-up and during partial loading. In these operating ranges, piston ring parts may impact on the sliding surface of the cylinder on the counter-pressure side and give rise, amongst other things, to undesirable noise. To obviate such impacts, the piston rod tapers at the end facing the crankshaft space on the counter-pressure side, and has a transversal slit (3) at its junction with the piston head and an adjustment strip (4) in the vicinity of the said slit. An additional adjustable strip (5) may also be provided in the lower part of the rod, on the pressure side. As a result of the position of the adjustment strips, the special design of the piston and the special shape of the rod casing, the piston head aligns itself at a slight angle to the counter-pressure side, with increasing play between the piston head and the sliding surface of the cylinder in the said operating ranges.

Abstract: In a piston whose rod 2 is connected in a hinged manner to the upper part of the piston through the piston axis and whose upper part, inside an annular support 5 in the central region of the base of the piston, is to be cooled by the cooling oil injected from the crankshaft chamber, the problem which arises is to introduce the cooling oil into this region without touching the annular support 5. In order to resolve this problem, a deflecting surface for the cooling oil in the shape of a channel section 11 is arranged at the upper end of the rod 2. This channel section 11 guides the injected cooling oil through a radial orifice 10 in the wall of the annular support 5 inside the central cooling chamber 9 below the base 4 of the piston. To improve the cooling effect of the cooling oil in the inner central chamber 9, the latter may be isolated from the crankshaft chamber by a cover 12.

Abstract: A process for the production of a cast piston upper part of a two-part piston comprising the steps of casting a piston head and a ring section having a collar of tab-type segments, wherein the tab-type segments have tapered ends; and bending over the tab-type segments in the direction towards the middle of the piston to form a lower closure serving as an annular cooling oil space.

Abstract: A two-part, low compression height, open-ended hollow skirt-type piston for internal combustion engines has a piston pin creating an articulated connection of the separate skirt and head parts. Guide portions (5) protruding axially in the direction of the piston axis provide lateral guidance and support of the piston head (1) in the piston-pin-axis direction. Each of the guide portions forms a gap with the nearby gudgeon pin boss (3). The gaps receive opposite parallel flat surfaces (4) of the skirt (2). The overhanging guide portions (5) have partly circular recesses permitting assembly of head and skirt with the gudgeon pin.

Abstract: A piston made of cast aluminum base alloy is provided with gudgeon pin bosses which are connected to the piston skirt by means of a frusto-conical strut which has recesses in the skirt and are specially dimensioned to leave large unsupported skirt areas to minimize risk of seizure in an engine cylinder; in particular the distance between the outer surfaces of the bosses is from 0.6 to 0.8 of the outer diameter of the piston and the distance between the inner surfaces of the bosses is 25 to 35 percent of the outer diameter of the piston, and the cone angle of the struts is from 60.degree. to 110.degree..

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: 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: In a plunger piston for internal combustion engines, having a regulating strip in the piston body, the regulating strip is arranged in the axial middle third of the height of the piston body and the regulating effect is designed so that the piston body possesses its narrowest installation play uniformly at the level of the regulating strip equally in the cold installation state and in the engine operation. Above and below this region with minimum installation play the piston body possesses spherically retracted end regions at its upper and lower ends for the generation of hydrodynamic lubricant oil wedges.

Abstract: In a plunger piston of aluminum for internal combustion engines the margin of the combustion chamber trough arranged in the piston crown is fiber-reinforced. The proportion of fibers in the basic material to be reinforced varies over the circumference of the combustion chamber trough margin. The marginal zone in the vicinity of the bolt axis (B) here possesses a higher fiber proportion than the trough margin zone adjoining the connecting rod oscillation plane (A). In this way a good temperature change stability of the marginal material is achieved in the zone adjoining the connecting rod oscillation plane (A) and a good fatigue strength is achieved in the zone adjoining the bolt axis (B).

Abstract: In a light plunger piston for internal combustion engines, in order further to save weight and to achieve an elastic running behaviour, the piston skirt is reduced to three relatively narrow guide plates. The guide plates are attached through longitudinal ribs to gudgeon pin bushes suspended freely from the piston crown. On the thrust side of the piston there are two of the three guide plates which extend, seen from a 45 degrees diagonal plane between gudgeon pin axial plane and connecting rod oscillation plane, through about 15-25 degrees to each of the two sides. On the counter-thrust side only one pressure plate is provided which extends circumferentially over about 50 degrees. There is preferably no direct connection between the guide plates and the lowermost ring land.

Abstract: A cast aluminum piston for internal combustion engines having mechanically compacted inner boss bore faces, the structure of the aluminum material disposed below these inner faces having a grain pattern orientated in the circumferential direction of the boss bore over a radial depth of at least 0.1 mm and preferably 0.2 mm. This grain pattern is achieved by rolling at a temperature of at least 350 degrees C. up to 400 degrees C. with simultaneous expansion of the bore diameter by about 0.2 to 0.5 mm.

Abstract: A multi-part plunger piston for internal combustion engines, comprises a piston upper part and lower part which engage one on the other through coinciding annular abutment surfaces. The parts are connected with one another by screws which pass through the annular surfaces. At least one of the annular abutment surfaces is domed in the circumferential direction in such a way that the annular surfaces are more strongly resiliently braced in the region between the screws in the finally assembled piston than in the regions around the screws. Due to the elastic initial stressing of the regions of the annular abutment surfaces between the screws it is intended reliably to avoid lifting away of the annular abutment surfaces in these regions during engine operation. When the finally assembled piston is in the cold condition the annular surfaces lie uniformly against one another over the entire circumference, admittedly with locally differing initial stresses.

Abstract: A piston for internal combustion engines, which has inclined surface portions in the skirt area to allow formation of hydrodynamic wedges of lubricant, these surface portions being constructed as skirt recesses (13 or 14) which are open either towards the upper or towards the lower end of the piston skirt. The transition zone from these skirt recesses to the bearing surface of the working surface of the piston is constituted by oblique surfaces which are inclined inwardly from the surface of the skirt. The oblique surfaces terminate in a circumferential direction within the bearing surfaces of the piston. The oblique surfaces constitute ramps on which a hydrodynamic wedge of lubricacting oil can form.

Abstract: In connection with a plunger piston for internal combustion engines, the connecting rod, which is hinged thereto via a gudgeon pin, is laterally guided at its small end by being in abutting contact with the internal faces of the gudgeon pin bosses. For this purpose, there are provided, only in the zone at the level of the gudgeon pin axis, limited contact surfaces between the connecting rod small end and the gudgeon pin bosses. By this means, the influence of deformations of the piston on the guidance of the connecting rod is eliminated to a very large extent.

Abstract: For a piston consisting of an Al-Si alloy having a mean linear grain diameter of the Silicon eutectic of more than 3 .mu.m for combustion engines and provided with a hard-oxidized top, the structure of the base material to be oxidized is subjected to a grain refinement in the depth to be oxidized so that the silicon eutectic has a mean linear grain diameter of less than 3 .mu.m, preferably less than 2.5 .mu.m. By this means, the resistance to erosion of the hard-oxide layer is improved. The grain refinement may be effected in the respective zones during the casting of the piston or thereafter by re-melting those zones prior to oxidizing. If the risk of erosion exists only in specific locally limited zones of a relatively large hard-oxide surface, then a grain refinement confined to these zones is sufficient.

Abstract: For the avoidance of the build-up of oil carbon in the ring grooves of the pistons of an internal combustion engine, the compression ring (1) has on its inner circumference, distributed over its entire height, a plurality of sharp edges which are formed by projections (2) or recesses (7). The edges are so aligned that, when the compression ring (1) rotates, they act in a scraping manner on any oil carbon that is building up in the radial bottom of the ring groove. The projections (2) or recesses (7) producing the edges are at least 0.5 mm high or deep. For reasons of strength, the sharp edges may be restricted to the ring zone between 70.degree. and 100.degree. on both sides of the ring joint. It is also possible to provide the sharp edges on an intermediate ring (6) to be inserted into the compression ring (1).