ЗНИЖЕННЯ ВУГЛЕЦЕВОГО СЛІДУ ДИЗЕЛІВ ШЛЯХОМ ЗАСТОСУВАННЯ ПАЛИВА РОСЛИННОГО ПОХОДЖЕННЯ

The article considers the impact of the use of alternative fuels of plant origin on energy efficiency, environmental performance and combustion processes in a motor-tractor diesel engine. The relevance of the topic is due to the need to reduce the carbon footprint of diesel engines in the context of tightening requirements for greenhouse gas emissions, increasing energy independence and ensuring fuel autonomy of critical sectors of the economy. The main attention is paid to the evaluation of diesel engine performance when running on fuel mixtures containing fatty acid methyl esters (FAME) and hydrogenated vegetable oil (HVO) in comparison with traditional petroleum diesel fuel. A review of the physicochemical properties of these fuels, in particular: density, specific lower heating value, cetane number, viscosity, flash point, oxygen content, and carbon-to-hydrogen mass ratio, was carried out. Design and technological limitations on their use in modern diesel engines are discussed. The efficiency of internal oxygen in FAME in the combustion process is evaluated based on the analysis of the chemical structure, thermal stability of ester groups, and kinetic conditions in the combustion chamber. The mathematical modeling of the 4CHN10.7/12.4 diesel engine's operating process was carried out in the Blitz-PRO software package using the real properties of the mixtures and the calculated parameters of the fuel equipment. Changes in the indicator and effective efficiency, specific fuel consumption, maximum cycle pressure, cylinder pressure rise rate, ignition delay period, and specific CO2 emissions were analyzed. It was found that with an increase in the proportion of HVO in the mixture, a significant decrease in the rigidity of the working process (up to 30%) was observed due to the high cetane number. At the same time, a slight decrease in efficiency is mainly due to a decrease in the volumetric heat of combustion and a shift in the heat release law to the later phases of the cycle. CO2 emissions were analyzed for different blends: a reduction of up to 6% is possible when using pure HVO. The full life cycle from raw material cultivation to fuel production has the potential to reduce emissions by 15-55% compared to petroleum-based diesel, according to the UK government. The results confirm the feasibility of using fuels from renewable sources in diesel engines as a tool for reducing the carbon footprint without significant losses in energy efficiency.