Impacts of pine oil and hydrogen induction with hemp oil methyl ester on dual fuel reactivity controlled compression ignition combustion in diesel engine

The current research focuses on the impacts of pine oil injection and hydrogen induction separately with hemp oil methyl ester (HOME) in the single cylinder diesel engine in dual fuel-reactivity controlled compression ignition (DF-RCCI) combustion mode. The engine was tested under a DF-RCCI mode for the different energy shares of 10% pine oil with HOME (10P-HOME), 30% pine oil with HOME (30P-HOME), 3-lpm hydrogen with HOME (3-lpmH₂-HOME), and 6-lpm hydrogen with HOME (6-lpmH₂-HOME) separately at 345 °CA bTDC of low reactivity fuel (pine oil and hydrogen) and 23°C bTDC injection timing of high reactivity fuel (HOME). The results showed a higher Brake Thermal Efficiency (BTE) of 7.44%, 5.32%, 5.72%, and 2.46% for 6-lpmH₂-HOME, 3-lpmH₂-HOME, 30P-HOME, and 10P-HOME fuel shares, respectively, over the conventional diesel combustion (CDC) at full load. 30P-HOME, 3-lpmH₂-HOME, and 6-lpmH₂-HOME fuel combinations recorded 4.08% 4.42%, and 5.69% lower brake specific fuel consumption (BSFC), respectively, at full load. When comparing DF-RCCI combustion to CDC, an increase in the heat release rate (HRR) of 2.89%–26.50% and a rise in peak cylinder pressure of 0.77%–12.99% were observed. The 30P-HOME, 3-lpmH₂-HOME, and 6-lpmH₂-HOME emit less smoke in DF-RCCI combustion mode by 13.06%, 4.84%, and 7.26%, respectively at full load condition. When using 30P-HOME the exhaust gas temperature (EGT) decreased by 3.50% at full load condition. At part and full load conditions, the 30P-HOME fuel share reduced oxides of nitrogen (NO_X) emissions by 3.93% and 5.26%, respectively.