Experimental Evaluation of Performance and Combustion Characteristics of Blended Plastic Pyrolysis Oil in Enhanced Diesel Engine

Plastic waste is the largest volume of waste and the most discarded, and it has a direct negative impact on the environment. Therefore, the pyrolysis oil process is an essential and sustainable solution to reduce plastic waste accumulation. However, the plastic pyrolysis fuel performance in diesel engines is reduced due to its lower cetane number. Diesel and pyrolysis oil were blended in ratios of 90:10 (BP10), 80:20 (BP20), 70:30 (BP30), 60:40 (BP40), and 50:50 (BP50) and applied in a single-cylinder diesel engine to investigate the engine performance and exhaust emission. The long ignition delay, thermal efficiency drops, and emission growth were found regarding the higher blended fuel ratios. BP30 was selected to evaluate the performance and combustion characteristics of blended plastic pyrolysis oil and diesel fuel blends by enhancing an unmodified engine using low hydrogen additions (1000 ppm) and advanced timing adjustment. The hydrogen injected into the intake manifold, along with the advanced fuel injection timing (−16.5 CA°BTDC), affected engine performance and emissions (CO, HC, and NO) at 1500 rpm under 25%, 50%, and 75% of the maximum load compared with diesel fuel. The results showed that the hydrogen addition was very positive for both engine performance and emission reduction, as the expanded flammability of the hydrogen promoted a wide range of combustion within the cylinder, whereas the advanced injection timing achieved improved engine performance but produced higher emissions compared to B7 at all engine loads.