Abstract: A combination of piston rings assembled to a piston includes a first compression ring, a second compression ring, a third compression ring and an oil ring. When an axial width of the first compression ring is h1(1), an axial width of the second compression ring is h1(2), an axial width of the third compression ring is h1(3) and an axial width of the oil ring is h1(4), h1(1)?h1(2) and h1(1)?h1(3), and when h1(TOTAL)=h1(1)+h1(2)+h1(3)+h1(4), h1(TOTAL)?3.1 mm.

Abstract: A piston for an internal combustion engine has box walls (18), which are each formed between skirt walls (12) and gudgeon pin bosses (10). At least one of the box walls (18) on a thrust side at least on the lower edge and at least on the inner side, starting from the gudgeon pin boss (10), in a first portion (20), runs largely straight and is inclined outwards, and then runs curved inwards, and then, in a second portion (16), runs largely straight and inclined inwards to the skirt wall (12).

Abstract: An integrally formed piston has a crown portion having an upper crown surface and an undercrown surface. A ring belt extends from the undercrown surface at a periphery thereof. The ring belt includes an uppermost ring land and at least one oil galley contoured to extend around at least two surfaces of the uppermost ring land. The oil galley has an opening at the undercrown surface for receiving a cooling fluid therein for cooling the uppermost ring land. A skirt extends from the undercrown surface and the ring belt and has a plurality of stiffening features arranged in a truss formation. At least one of the plurality of stiffening features has an I-beam cross-section and another of the plurality of stiffening features has a negative draft angle.

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 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: Pistons are described having improved stiffness of the lower skirt regions to improve piston guidance and oil film distribution. The pistons comprise a crown portion including piston ring grooves and a skirt portion, the skirt portion being divided into an upper skirt region and a lower skirt region and wherein on each side of the plane including the piston axis and the gudgeon in axis the support skirt region includes at least one bearing surface and the lower skirt region comprises a bearing surface supported by two substantially planar skirt wall sections lying in planes forming an acute angle of less than 75.degree. with the plane which includes the piston and gudgeon pin axes, the maximum bearing contact arc of the lower skirt bearing surface lying between 10.degree. and 22.5.degree. either side of the lane which is normal to the gudgeon pin axis and which includes the piston axis.

Abstract: A piston for an internal combustion engine is provided with two separate skirt portions on either side of the gudgeon pin bore. Each skirt portion is the shape of a sector of a cylinder and is cantilevered on a pair of struts connected to the skirt members at points intermediate their top and bottom edges. The skirt members have top and bottom bearing surfaces which provide the running surfaces against the associated cylinder or liner and which are connected to the centers of the skirt members by flexible flanges. This allows these running portions to flex and absorb substantial lateral loads without creating noise so that the piston is quiet as well as being lightweight.

Abstract: A piston comprising a head, a pair of opposed boss-carrying elements depending from the head and a pair of opposed skirt portions separated from each other and from the head. The skirt sections are supported from the boss-carrying elements by upper and lower pairs of struts each joined at one end to an adjacent skirt section and at the other end to an adjacent boss-carrying element. The end portions of each strut of the lower pair form an angle of between about 90.degree. and 180.degree.. The end portions of each strut of the upper pair form a substantially smaller angle than the end portions of the struts of the lower pair. The lower struts are stiffer than the upper struts.