Fully variable, simple and efficient - electrohydraulic - valve train for reciprocating engines

A new camless electrohydraulic valve train concept for combustion engines was developed at Empa (Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland) and tested on a spark ignition passenger car engine. Besides full flexibility with regard to lift and timing of the engine gas exchange valves it features robustness, simplicity and in particular a low own drive power need due to a maximum of hydraulic energy recuperation. The engine test results confirm substantial efficiency gains in classical as well as in hybrid power trains while also maintaining additional advantages. The system also has the potential to become a key element for load control of piston based compressors and expanders, reciprocating Joule Cycle engines and derivable future electricity storage systems.