Combustion concepts for future SI engines try to meet CO2-emission commitments and legislation all over the world. Where the Diesel engine has an advantage by principle, the efficiency of the SI engine has to be improved significantly, while of course the exhaust emissions must not become worse.
An approach is to reduce the gas exchange losses using fully variable valve trains on the intake side of the combustion engine. OptiVent is a patented new way of controlling the mass air flow in the cylinder of a combustion engine using opening valves during the compression phase of a four stroke engine. This technology regards a wider range of variability on the valvetrain components of the engine especially for opening the valves more than one time during a cycle. On the other hand it is necessary to combine this technology with direct injection to avoid fuel losses in the exhaust system and raising the exhaust hydrocarbon emission of the engine.
Chemnitz University of Technology and the West Saxon University of Applied Sciences in Zwickau had performed numerical investigations on the potential of the OptiVent engine control and combustion system, using a fully variable valve train on the exhaust valves of the engine.
The paper presents results from numerical simulations of the gas exchange, the mechanical losses of an engine with cylinder deactivation using OptiVent and regarding the effort for the starting process of engines with this new technology. The simulations show the potential of the new OptiVent-way of air mass control, so that the research can progress toward developing a running engine and testing it on a test bench. The research is funded by government and industrial partners.