Impact of High Performance Combustion Chamber Alloys on Fuel Efficiency

Internal combustion engines have been developed for over one hundred and twenty years and are a very mature technology. Over this time, significant improvements in power density and brake thermal efficiency have been realized from improvements in design, processing and material properties. Huge advances in computer simulation capability over the past thirty years have enabled the former two categories to be explored and exploited very thoroughly, leaving materials specifications as the fundamental key to unlocking further efficiency gains. This paper summarizes the design advantages of a range of alternative materials developed for piston, ring connecting rod and bushing applications. A Ford Ecoboost 2.3l RS engine was selected as a baseline engine and the reciprocating parts were re-designed to take advantage of the improved characteristics of these materials. Reciprocating mass, mechanical efficiency and crevice volume savings have been demonstrated from the re-designed components: piston, pin, ring, connecting rod and bushing. A dynamometer test program was devised to evaluate the net improvements in engine operating efficiency from the modified engine, based on a series of steady-state reference points comparing the baseline OEM and modified engines for future engine testing.