Experimental investigation performance and emission of hydrotreated pyrolysis oil in a heavy-duty engine with EGR

Drop-in biofuels can play an important role in the transition from fossil-based fuels to carbon-neutral energy carriers. This work focuses on performance and emission of hydrotreated pyrolysis oil (HPO) for heavy-duty (HD) engines application. The HPO is blended with marine gas oil (MGO) in various mass ratios and tested both in combustion research unit (CRU) and engine facilities. Typical cruise speeds and multiple loads are selected in the heavy-duty engine tests. Both inlet temperature and EGR rate are varied to investigate the effects of control parameters on HPO. The results reveal that HPO present lower reactivity than MGO and diesel under CRU condition. It can function as a drop-in fuel without any modification to the engine and no recalibration was required. Specifically, key combustion phases are noticed to be identical. The engine can run smoothly and safely at 50% blend ratio with 1% reduction on net indicated efficiency (NIE) and 0.002 g/kWh particulate matter emissions (PM). At low load, the NOx emissions decrease to 1 g/kWh at 40% EGR, yet 1% decrease of NIE is shown. While all fuels yield more NOx but less PM emissions as the increase of inlet temperature. Inlet heating does decrease the NIE by 1%. •Engine can be fueled with 50% hydrotreated pyrolysis oil blends safely.•Soot/NOx emission tradeoff is noticed for hydrotreated pyrolysis oil blends.•Hydrotreated pyrolysis oil yields less indicated efficiency than commercial fuels.•Inlet heating barely influences combustion and decreases 1% net indicated efficiency.•At 40% EGR, 1 g/kWh ISNOx is achieved while keeping ISPM below 0.1 g/kWh.