Metallgesellschaft Aktiengesellschaft

Kolbenschmidt Aktiengesellschaft

Gunder Essig

Wilfried Sander

Erich Wacker

Manfred Bordt

In a light alloy piston each of the load-carrying skirt surfaces is divided into a plurality of load-carrying skirt surface portions. In order to ensure that the upper portion of the piston skirt will carry load on a large area even when the engine is warming up, a plurality of depressions extending in the peripheral direction of the piston skirt are formed in the latter between its clearance-defining top and bottom ends.

Light alloy piston

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 1.5 to 2.5 mm.

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Heilbronn, Germany

Gunder Essig