Experimental Assessment of ‘Drop-In’ and ‘Optimized’ HVO Usage in a 6.6l Diesel Engine for Low-Emissions Marine Applications

All mobility sectors are facing the challenge to contribute actively to the reduction of environmental pollution and of the impact on climate change driven by Greenhouse Gas effect. One of the most active sectors in the research of environment-friendly propulsion propositions is the recreational and light-commercial boating. Presently, many of the boats operating in this sector are propelled by internal combustion engines derived from road applications. In this work, the effects of replacing conventional fossil-derived B7 diesel with Hydrotreated Vegetable Oil (HVO) were experimentally investigated in a modern Medium-Duty Engine, using the advanced biofuel initially as drop-in replacement, and then repeating the testing after the recalibration of the engine combustion set points. Comparing the results of the replacement of diesel with HVO showed appreciable benefits in terms of NOx, Particulate Matter (PM), mass fuel consumption and Well-to-Wake (WtW) CO₂ thanks to the inner properties of the aromatic-free, hydrogen-rich renewable fuel, in both drop-in and modified engine tests. Additionally, this specific engine-fuel combination gained in emissions without decreasing the engine power and limiting the increase of the volumetric fuel economy.