Abstract
The scope of downsizing concepts is fuel consumption reduction as well as costs reductions in comparison to large displacement engines with natural aspiration (ENA) and the same power output. This is achieved by using small displacement engines with different types of super-charging systems as turbocharger (TC) or mechanical driven volumetric supercharger (MVC). For these reasons the international automotive industry is developing with great financial effort downsizing engines, especially those with turbocharger systems. But all new cars with downsizing engines have not achieved the proposed targets.
The purpose of this paper is clarification of the reasons that lead to contradictory results, and to formulate criteria to identify optimal solutions of the downsizing concepts, both in terms of fuel economy as well as production costs. Our own theoretical and experimental research for different gasoline and diesel engines will be presented. The studies have been carried out for BMW, Mercedes, Porsche, Opel, Renault and Dacia engines. The results show that the potential for increasing efficiency and cost reduction for various engine types is relatively high.
Keywords: Downsizing, turbocharging, supercharging, fuel efficiency, costs.