Federal-Mogul Powertrain has introduced two innovative piston skirt coatings: EcoTough-New Generation (for gasoline engines) and EcoTough-D (for diesel engines). Building on the proven performance of previous EcoTough coatings, the new formulations further reduce engine friction, wear and noise while dealing with the increasingly challenging loads and temperatures that exist in the latest downsized, turbocharged engines.
Gasoline and diesel engines require alternative solutions because of important differences in their relative combustion loads, piston geometry and the lubricity of their respective fuels. Federal-Mogul Powertrain has accommodated these differences by formulating specific coatings, each optimized for either gasoline or diesel application.
The piston skirt and piston pin alone account for around 17 percent of the frictional losses in an engine. Skirt coatings have proved to be an effective way of meeting the interrelated targets of reduced friction and wear between piston skirt and cylinder surfaces, used in combination with optimum piston clearance and skirt geometry. Application of the piston skirt coatings using a fully automated, large-scale production process means that the excellent wear and friction properties can be achieved within economical cost targets.—Dr. Frank T.H. Dörnenburg, Head of Technology, Global Pistons at Federal-Mogul Powertrain
EcoTough-New Generation coating is a metal oxide-reinforced resin with additional embedded solid lubricant particles. The coating, which is applied in a thickness of 15 microns, reduces skirt wear in gasoline engines by up to 40% compared to the market standard and offers significantly improved fatigue strength under extremely harsh conditions.
It also delivers piston friction reduction gains of up to 15% compared to standard coatings, directly improving the efficiency of the base engine.
Following extensive rig testing and engine-based development, sample pistons with the EcoTough-New Generation coating are currently completing validation programs with vehicle manufacturers.
EcoTough-D has been developed for both aluminium and steel diesel pistons, in passenger cars and commercial vehicles. Taking advantage of the greater structural stiffness of diesel pistons and the superior lubricity of diesel fuel, Federal-Mogul Powertrain was able to specify a different formulation and deliver even greater improvement in friction levels.
A polymer-based coating reinforced with short carbon fibres and containing graphite embedded as a solid lubricant, EcoTough-D reduces piston friction by as much as 35% compared to conventional coatings in the market. Wear resistance is also improved by up to 30%.