One-fifth less friction with new piston assembly
In response to the need to curb fuel consumption and CO2 emissions, of growing importance, especially on commercial vehicles, is a reduction in engine friction. Over the past years, first-tier auto-industry supplier Rheinmetall Automotive (former KSPG) has systematically broadened and honed its expertise in this area. The outcome: through its subsidiary KS Kolbenschmidt, this specialist has achieved 20-percent less friction on a new low-friction piston assembly compared with the existing piston assemblies used on today's 2016 engines models. What's more, the reduced height of the new piston assembly also lowers overall engine mass.
This significant step forward has been facilitated by a detailed improvement package and hence the still low and, in some cases, even lower oil consumption not only reduces fuel consumption and emissions on engines for powering both on- and offroad commercial vehicles, it spells advantages in terms of leaner fleet operating costs and, not least of all, less harm to the environment.
A key role in the friction reduction measured is played by a completely customtailored piston assembly consisting of piston, piston rings, cylinders, piston pin and connecting rod. The individual parts of the total assembly are meticulously matched to the application requirements in terms of such parameters as geometry, surface properties, shape, and coating.
The tribology of the individual components and their best-possible interaction is a complex challenge with a host of reciprocal effects. So, in order to accurately record the measurements while the engine is running, KS Kolbenschmidt has developed its own purpose-engineered friction test bench. Included in the integrated system are slide-honed cylinders sourced from a cooperation agreement with GKN Cylinder Liners as well as special low-friction piston rings co-engineered with alliance partner Riken.