Comparative Evaluation of Performance Parameters of Conventional and Waste Fuels for Diesel Engines Towards Sustainable Transport

Sustainable development and growing energy demand require the search for alternative fuels, especially for heavy transport. The study compared diesel fuel (DF), hydrogenated vegetable oil (HVO) and fuels from the pyrolysis of polypropylene (PPO), polystyrene (PSO) and car tyres (TPO). The lowest cold filter plugging point values were obtained for HVO (−38 °C) and PSO (−29 °C). TPO and DF were in the moderate range, while PPO achieved the worst result (−10 °C). Only DF met the EN 590 standard requirements for density at 15 °C (0.820–0.845) g/cm3. HVO and PPO were approx. 5% below the lower limit, while PSO and TPO exceeded the upper limit. All samples except PPO, which was below the lower limit, met the kinematic viscosity requirement according to the same standard at 40 °C (2.0–4.5) mm2/s. Based on a series of tribological tests, it was found that DF (400 µm) had the lowest lubricity expressed by the WSD index, while PSO (246 µm) had the highest. All samples tested met the requirements of EN 590, ASTM D975 and the Worldwide Fuel Charter in this respect. The results provide valuable information for engine technology, enabling more accurate durability predictions and fuel mixture optimization.