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Posted on: 9/9/2011 12:00:00 AM... Federal-Mogul Corporation of Southfield, Michigan, has developed a piston technology with Mercedes-Benz that can offer fuel economy and low emissions, while still maintaining performance in premium downsized engines. The cast aluminum-silicon alloy pistons are pre-machined and welded into place by a robot that applies a precisely defined energy input around the rim of the bowl in a single pass. The re-melted alloy cools a thousand times faster than when it was originally cast, producing silicon particles that are one tenth of their previous size. This refinement of the microstructure increases the alloy's strength and durability.

The new technology allows piston crown geometries that help to burn fuel more efficiently, while increased durability helps designers to reduce piston mass and improve performance.

The large-bowl combustion chamber in Daimler's OM642 V6 3.0-liter diesel features a piston crown with an enlarged bowl recess with steep sides and a sharp cutback below the rim. To strengthen the piston crown, a high-voltage, high-amperage form of Tungsten Inert Gas arc welding (TIG) remelts the metal around the bowl rim into a highly durable microstructure.

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