Model-Based Optimization of Diesel/OMEx Fuelled CI Engine under Multiple Blending Conditions

The search for alternative solutions for vehicle electrification, while reducing the carbon footprint during the transition to green mobility, leads to the investigation of electro-fuels (e-fuels) in conventional internal combustion engines. Leveraging previous research, the present study focuses on the optimisation of a Compression Ignition (CI) engine combustion control in response to the use of the Oxymethylene Dimethyl Ethers (OMEx) blended with conventional diesel. The selected e-fuel is the OME₃, which is expected to be used as a drop-in solution and to easily achieve a reduction in soot emissions due to both its high oxygen content and lack of direct carbon bonds in its molecular structure. To verify its potential, a 1D single-cylinder CI multi-zone engine model has been exploited to simulate various diesel/OME₃ blends in a wide engine operating range. The first step deals with the evaluation of performance and emissions to demonstrate the differences, particularly in terms of emissions reduction compared to the baseline standard configuration. Each operating condition is then optimized to minimize the energy losses associated with fuel substitution while maintaining the beneficial emission reductions. The model parameters identification and the optimisation of the different blends for each engine operating point are carried out using the software GT-Suite. This approach aims to provide an assessment of the methodology to design new control strategies along with the analysis of the potential impact of using such blends. On the basis of these results, a further optimization was carried out to assess, for each optimized operating point, which blending ratio guarantees the best performance both in terms of emissions and fuel consumption.