Mahle Gmbh

Hanspeter Wieland

Peter Kemnitz

Michael Ullrich

Emil Ripberger

Valery Bauer

The invention relates to a cooled piston () for an internal combustion engine comprising a cooling duct (). This cooling duct encircles in an annular manner inside the piston head at the height of the ring part and is closed at its end, which is open toward the piston skirt, by men of a spring part (). Said spring part is correspondingly shaped, is radially divided at least once on the periphery thereof, and provided with a cooling oil inlet (). The aim of the invention is to achieve an improved location-dependent removal of heat from the particularly hot portions of the piston (). To this end, an encircling oil guiding ring () is placed inside the cooling duct () and, from the cooling oil inlet () to the cooling oil outlet (), symmetrically divides the cooling duct () on the periphery thereof into sections () of different cooling duct volumes.

Cooled piston for an internal combustion engine

Cooled two-part piston for internal combustion engines having an upper piston part containing the piston ring grooves and piston pin bosses, and a piston skirt connected with the former exclusively by way of a piston pin. The upper piston part has a cooling oil annular channel that is open towards the piston skirt, into which channel the cooling oil is introduced, and discharged. There are collecting pockets attached at the upper end of the piston skirt, which faces the upper piston part. The pockets at least partially cover the cooling oil annular channel. When the engine and piston are arranged horizontally, a tub-shaped recess is provided in an interior bottom region of the piston skirt for accommodating cooling oil. The circumferential wall limitation of the recess is formed exclusively by a wall of the inside piston skirt.

Cooled piston consisting of two parts

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.

Piston with specific land characteristics

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.

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Ditzingen, Germany

Hanspeter Wieland