This work has focused on preparing the grounds for large-scale use of 2nd generation vegetable oils in advanced engines, notably in hybrid engines. Engine development work was done to further optimise the operation of engines with vegetable oil under quasi-constant load. Fuel development, comprising intra-blending of different vegetable oils and development of additives, were done for optimising the suitability of vegetable oil under a broader range of operating conditions. Further, suitable engine oils were developed and tested. Medium-size demonstration fleets were run in France, Austria, Germany and Poland with rape seed, sunflower, camelina sativa and jatropha oil.
The consortium partners consider hybrid engines as the most advanced engine concept which still includes an internal combustion engine. Hybrid engines allow achieving very low exhaust gas emissions and saving considerable energy compared to state-of-the-art engines. As hybrid vehicles were not yet available for fleet demonstrations – except high-end luxury-class vehicles from Toyota – hybrid engine operation with 2nd generation vegetable oil was only done on an engine test stand of the Technische Universität München (Technical University of Munich), while tractors were taken for the medium-scale demonstration fleets.
Tractors as well as hybrid engines operate at quasi-constant load conditions. The latter allow achieving the very low emission levels with vegetable oil as fuel. So, the results of the tractor demonstration fleets arehighly relevant for hybrid engine concepts. The transfer of the achieved concepts were checked in the hybrid engine test stand experiments. The overall results were laid down in a European draft standard fuel specification for optimal dissemination.