CO₂-Potential of a Two-Stage VCR System in Combination with Future Gasoline Powertrains

Authors

Dipl.-Ing. R. Weinowski, Dr.-Ing. K. Wittek,
Dipl.-Ing. B. Haake, Dipl.-Ing. C. Dieterich,
Dr.-Ing. J. Seibel, Dr.-Ing. M. Schwaderlapp, FEV GmbH, Aachen; Dr.-Ing. D. Tomazic, FEV Inc., Auburn Hills, MI, USA

Year

2012

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 735

Summary

Downsizing in combination with turbocharging currently represents the main technology trend for meeting CO2 emissions with gasoline engines. Besides the well-known advantages of downsizing the compression ratio has to be reduced in order to mitigate knock at higher engine loads along with increased turbocharging demand to compensate for the reduction in power. Another disadvantage occurs at part load with increasing boost pressure levels that cause the part load efficiencies to deteriorate. The application of a variable compression ratio (VCR) system can help to mitigate these disadvantages. This article entails a two-stage variable compression ratio mechanism realized by varying the connecting rod length. It includes a description of the system layout, working principle and the expected fuel consumption benefits applied to current as well as future gasoline CO2 engine concepts.

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