WIESBADEN, GERMANY -- Federal-Mogul Corp. said it has collaborated with Mercedes-Benz to develop a piston technology for Daimler’s latest V6 diesel engine that helps reduce fuel consumption and emissions.
The company said the design gives Mercedes-Benz a piston that exploits advances in thermal and mechanical durability made possible by Federal-Mogul’s DuraBowl manufacturing process. Federal-Mogul’s DuraBowl piston technology will be exhibited at this year’s Frankfurt Auto Show.
Federal-Mogul said its DuraBowl technology allows piston crown geometries that help to burn fuel more efficiently, improving combustion efficiency and reducing emissions. DuraBowl’s increased durability also helps designers to reduce piston mass while improving performance. These attributes all lead to reductions in diesel engine fuel consumption and emissions, with improved power output.
“The rising specific output of downsized diesel and gasoline engines place higher thermal and mechanical loads on many of the key components where Federal-Mogul has expertise,” said Federal-Mogul President and CEO José Maria Alapont. “The DuraBowl piston process shows how we are delivering specialized process technologies that help our customers meet these challenges successfully and support sustainable global profitable growth.”
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. It helps reduce emissions to EU5/EU6-levels by lowering the compression ratio to 15.5:1 from 18:0 (EU4). To strengthen the piston crown, Federal-Mogul’s DuraBowl process uses a high-voltage, high-amperage form of Tungsten Inert Gas arc welding (TIG) to re-melt the metal around the bowl rim into a highly durable microstructure.
“DuraBowl extends a piston’s fatigue resistance by four to eight times under cyclic thermo-mechanical loading,” said Rainer Jueckstock, Federal-Mogul senior vice president of powertrain energy. “The process required extensive development to produce the ideal current and voltage to deliver optimum results and consistent high quality within just 18 months. The result is a leading, technically advanced, high-performing and very cost-competitive product.”
Federal-Mogul pre-machines the cast pistons used in the DuraBowl process. A welding robot then 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 company said.