Hydrogen as a Carbon Neutral Fuel for Automotives in Sustainable Transportation

The use of sustainable carbon-free energy sources is becoming a priority in the field of transport so that it becomes sustainable. Sustainable transport can also be achieved with vehicles equipped with diesel engines fuelled by alternative fuels that do not contain carbon, like hydrogen. The paper presents an analysis of the experimental results obtained at the fuelling with diesel fuel and hydrogen of a modern diesel engine, operating at 50% partial load and 2500 rev/min speed. For H2 energy substitution degrees of up to 43%, the combustion process is improved: the specific energy consumption is reduced, the combustion duration is reduced, the heat release rate is increased, the maximum pressure is increased, the carbon-based pollutant emissions are decreased and the cyclic dispersion is reduced. For 33% H2 energy substitution degree, the maximum pressure increases by 16.4%, the indicated mean effective pressure increases by 7.5%, the specific energy consumption is reduced by 5.36% and the level of greenhouse gases emission is reduced by 34.5% for carbon dioxide. In case of pollutant emissions, the smoke level is reduced by 58.6% and the unburned hydrocarbons level is reduced with 18%. For higher percentages of H2, emissions reductions can be accentuated. At H2 use, the combustion cyclic variability is reduced, the values of the COV variability coefficients determined for the parameters of interest and the combustion duration being reduced. As a novelty aspect, the optimal adjustment between engine load-speed-diesel fuel flow-hydrogen flow-maximum combustion pressure-smoke emission level-exhaust temperature level is presented. The use of hydrogen at the diesel engines can provide the beginning of sustainable transportation solutions in the future.