The coating ensures less friction in the motor cylinder between the coated piston pin and the connecting rod bushing.
Image: Frauenhofer IWS
Where there is friction, there is energy consumption. This is of particular importance in the industry since increasing electricity costs worry all operating companies. Motors that are driving pumps account for a large portion of the energy used. One approach to lower this consumption is the reduction of friction by means of surface treatment. In the joint project “Prometheus”, researchers from the Fraunhofer Institute for Material and Beam Technology (Fraunhofer IWS) together with representatives from the industry developed processes precisely for this purpose.
“Diamond-like” is the word used by the institute to describe the coatings and surfaces that are initially intended to help in lowering consumption primarily for motors in cars, trucks, and buses. The goal is to match the surface and the lubricant in the best possible way to reduce friction. “Currently, there are already super-hard, diamond-like carbon coatings,” explains Dr. Volker Weihnacht, who heads the research project in the Fraunhofer IWS. “We optimized them even further and, among other things, added various elements to the graphite that is vaporized through the plasma process.”
The interaction of these components is especially important in the development. According to the institute, the carbon layers with the brand name Diamor that are created in the IWS have the highest potential for friction and wear reduction. They consist of up to 70 percent diamond bond content and are created using the laser arc process, which was specifically developed for these layers.
The researchers are collaborating with manufacturers of motors and components as well as materials and lubricant experts. Twelve partners are involved in the Prometheus research project, which started in January 2019. The results will be transferred to series production readiness. The crucial factor for the industry is that the solutions can potentially be used in friction bearings, like those used in pumps. This could possibly result in a significant reduction of their consumption in the foreseeable future.
Coated piston rings seal the combustion chamber against the crankcase and create less friction while sliding against the cylinder wall.
Image: Frauenhofer IWS