Karl Schmidt Gmbh

Kolbenschmidt Aktiengesellschaft

Horst Moebus

A composite piston for internal combustion engines has an interior cooling chamber and an outer cooling passage. An annular rib protrudes from the inside surface of the upper part and that surface of the lower part which faces that annular rib. An annular flange is clamped between said rib and said surface of the lower part. A tongue which protrudes into the cooling passage is provided on that edge of said flange which faces the cooling passage. In order to minimize the temperature of that surface of the cooling passage which is near the combustion chamber and to maintain at least adjacent to the uppermost ring groove a temperature which is sufficient to prevent a wet corrosion of the piston and of the piston rings, the tongue defines a relatively narrow annular gap with that surface of the cooling passage which is near the combustion chamber so that the coolant oil is throttled as it flows through that gap.

Liquid-cooled composite piston for internal combustion engines

In a cooled composite piston having a cooling passage adjacent to the interface and a method of making same, the upper part consists of forged steel and is formed on its underside with ribs bearing on mating surfaces of the lower part. To improve the resistance to thermal and mechanical stresses, the upper part has been welded by means of charge carrier rays to the lower part, which consists of cast ferrous material.

Piston for internal combustion engines

In a composite, liquid-cooled piston, the upper part consists of ferrous material and is joined by conventional means to the lower part. A ring is provided on the underside of the upper part which bears on the corresponding surface of the lower part and constitutes a radially inner boundary of a cooling passage which is disposed on the upper part and open to the interfacial plane. To improve the cooling action in the hottest regions of the upper part and to achieve a more uniform distribution of temperature in the ring carrying over of the upper part of piston, the upper portion of the wall defining the cooling passage is coated with a material having a high thermal conductivity.

Liquid-cooled piston for internal combustion engines

In a liquid-cooled, composite piston for internal-combustion engines, particularly for medium-speed diesel engines, comprising a lower part, which made of a material comprising an eutectic aluminum-silicon alloy which lower part is connected to an upper part comprised of a ferrous material, said upper part formed on its underside with a concentric top rib, which rib forces the opposite bearing surface of the lower part and is so arranged that the rib constitutes the radially inner boundary of an annular cooling channel, which is disposed in the upper part behind the top land of the piston and behind at least part of the ring-carrying portion of the piston said rib also defining a central cooling chamber, which is disposed in the upper part and which communicates with the cooling channel by radial coolant bores, the improvement comprising a ring comprised of a ferrous material concentrically disposed and gripped between the bearing surface of the bearing rib and the opposite bearing surface of the lower part of the piston in an arrangement in which the confronting bearing surfaces of the bearing rib and the gripped ring are in peripheral rolling contact with one another.

Liquid-cooled, composite piston for internal-combustion engines

In a liquid cooled, assembled piston for an internal combustion engine which has a lower piston part, an upper piston part connected thereto, an annular cooling passage disposed in the upper piston part behind the top land and at least part of the ring-carrying portion thereof, an input coolant conduit in the lower piston part, a central cooling chamber disposed between the two piston parts and a supporting ring concentrically disposed on the underside of the upper piston part and between the annular cooling passage and the central cooling chamber, there is provided an oil guiding ring including a flange gripped between the two piston parts and a lip connected to the flange and protruding into the annular cooling passage for effecting the flow of the oil along the periphery of the cooling passage as it enters same from the input coolant conduit.

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Neckarsulm, Germany

Horst Moebus