Performance and Emission Analysis of Diesel-Turpentine Blends in a Compression Ignition Engine

Abstract

This study investigates the effects of diesel blended with turpentine oil and oxygenated additives namely turpentine–diesel, oxygenated turpentine–diesel) alpha-pinene–diesel, and oxygenated alpha-pinene–diesel on engine performance, combustion characteristics, and emissions in a single-cylinder compression ignition engine under various speeds and loads. The in-cylinder pressure (ICP) analysis reveals that all blended fuels showed higher maximum ICP values than diesel, ranging from 76 bar to 79 bar compared to 75 bar for diesel, an improvement of approximately 1.6% to 5.3%. The heat release rate (HRR) analysis indicates that additive blends enhanced combustion, with maximum HRR reaching 73 J/°CA for TD, compared to 68 J/°CA for diesel, which is an increase of up to 7.3%. CO₂ emissions for additive blends were slightly higher than D, with OAPD reaching up to 0.6% compared to 0.21% for diesel. Carbon monoxide emissions showed minimal differences, with peak values between 0.043% and 0.046% across all fuels. Notably, NOₓ emissions significantly increased, with APD reaching 230 ppm compared to 220 ppm for D, reflecting an increase of up to 50%. The ANOVA results confirm that engine speed and load are statistically significant parameters (p < 0.0001) affecting combustion and emissions. The study concludes that additive-diesel blends enhance engine performance metrics such as ICP and HRR but with trade-offs in NOₓ emissions due to intensified premixed combustion.