Surrogate Fuel Definition And Spray Calibration For Diesel Engines

Reducing the greenhouse gas emissions is one of the most important targets in the automotive industry and to do so, a shift to carbon-neutral fuels is one of the most promising alternatives. Due to their composition, hydrotreated vegetable oils (HVOs) are very high quality bio-based diesel fuels, with no negative effects on engines or exhaust after treatment system. In partnership with ENI, a research activity at the Energy Department in Politecnico di Torino has been started to investigate the effects of using HVO instead of a conventional diesel fuel. The first step has been the development of a CFD model of a light-duty commercial vehicle equipped with a compression-ignition engine powered with conventional diesel fuel. In the present thesis, as next step, a surrogate fuel approach to simulate the HVO has been developed and the spray CFD model has been calibrated. Numerical results are validated against experimental data, available on the ECN platform, in terms of liquid and vapor penetration, ignition delay and location, lift-off length and soot mass formation. In the first part of this thesis a theoretical background on CFD fundamentals and the CONVERGE CFD software is provided. The second part deals with the development of the fuel surrogate approach. In the third part, finally, the spray model using the surrogate fuels is calibrated and results are validated against the experimental data. Next steps in this project will be the implementation of this surrogate fuel approach in real engine CFD models and the testing of the HVO fuel in a real engine in order to provide experimental data