Third party funded individual grant
Acronym: WiDiKo
Start date : 01.01.2011
End date : 30.06.2014
In the BFS research project WiDiKO Effect Chain of Directly Injected Fuels in Gasoline Engines the influence of individual fuel components (partly biogenic components) on the gasoline engine effect chain starting with spray propagation and evaporation behavior up to ignition and flame propagation for direct-injected gasoline engines was experimentally investigated, physically based modeled and thus made accessible for simulation. Overall, it can be stated that the different properties of the components contained in gasoline fuels have a considerable effect under the temperature and pressure conditions that exist in modern gasoline engine processes, in that they significantly influence the spray behavior in gasoline direct injection, while partial separation of the components can occur during vaporization and the components show significant differences in ignition and flame propagation behavior. The project was able to expand the state of knowledge in the above-mentioned points by better understanding and modelling the behaviour of multi-component fuels and thus making it accessible to a well-founded simulation. In particular, the behaviour of short-chain alcohols (ethanol, butanol), which are frequently used as biogenic components, in the mixture with mineral oil-based hydrocarbons in the evaporation process was shown to be dependent on the operating point. The correct mapping of the mixture thermodynamics for fuels containing ethanol in an evaporation model is a major project result. With regard to the ignition conditions, the injection timing showed to be the dominant influence over the evaporation cooling. With regard to flame propagation, all measured data (pure substances, binary and ternary mixtures, gasoline and residual gas influence) could be correlated very well with data on laminar flame velocity. For the measurement of these laminar combustion velocities of liquid hydrocarbons, a new measuring method ("Heat-Flux-Burner") could be established cooperatively at both participating institutes. In addition to numerous publications, the research project has led to joint further research activities (successful application for a junior research group at the BMEL, at the FVV and FNR). The 0D/1D simulation of engine processes, which is used at BMW and is widely used in industry, was able to benefit significantly from this project and also contribute to the validation of the dependencies between ignition and combustion. Here, the interactions of the project results in the area of laminar flame velocities are particularly noteworthy.
The overall project is divided into three subprojects:
Subproject A (LTT Erlangen): Experimental investigation of the component-dependent spray behaviour, evaporation behaviour and combustion
Subproject B (IEC Freiberg): Simulation of spray propagation and evaporation for single and multi-component fuels
Subproject C (BMW AG): Engine combustion model for current gasoline engines