Functionality and Potential of a New Electrohydraulic Valve Train
Besides defossilization, a continuous improvement of internal combustion engines is one way to reduce the CO2 emissions of vehicles. For that, variability in the valve train - combined with the possibility to deactivate cylinders - is essential. The FlexWork valve train presented here by Empa and the Wolfgang Schneider engineering office offers all required degrees of freedom despite a simple operating principle and low energy demand, leading to a reduction in fuel consumption of 10 to 20 %.
FlexWork it is a new, cam-less and fully variable valve train with an energy demand lower than that of a cam-driven valve train. Valve lift and valve timings can be selected freely on the intake and exhaust side. Due to its simple and robust design, the valve train is not simply a research tool but can also be seen as the basis for further development for mass production by an industry partner. In this article experimental results of the steady state dethrottled operation with...
The authors thank the Schweizerische Bundesamt für Energie for their financial support in the scope of the FlexWork project and the technology partners Mubea, Elgo Electronic, Hydac, Bieri-Hydraulik, and BASF. Thanks are also due to Bernhard Rüst, who supported the developments with great input and his work to the state of the art of variable valve train technologies, and to the Bildungs- und Forschungsfond of the Verband der Schweizerischen Schmierstoffindustrie, which financed preliminary work.