Influence of Oxygenated Hemp Seed Biodiesel Blends on Performance and Emission Phenomenon at Variable Compression Ratio of Compression Ignition Engine

The focus of this study is to assess the performance and emission parameters of the oxygenated blended fuel of hemp seed biodiesel at various compression ratios (17:1, 17.5:1, and 18:1) using a single-cylinder four-stroke direct injection compression ignition engine. Hemp seed bio-oil was extracted using the soxhlet apparatus. Single-stage transesterification process was adopted due to lower free fatty acid content. Methanol and sodium hydroxide was used as reagents. The ternary test fuel blend was prepared by adding the diesel-HSBD with 10% of diethyl ether (DEE). Higher brake thermal efficiency (BTE) of 33.98% was observed for D80HSBD20DEE10 at CR 18:1, whereas CR 17.5:1 and CR 17:1 gave a 3% to 6% lower BTE. The brake-specific fuel consumption (BSFC) for D80HSBD20DEE10 blend showed a marginally lower value at CR 17:1. But, it increased up to 373 g/kWhr upon increasing the CR to 18:1. Exhaust gas temperature increased with increase in compression ratios. UBHC and CO emissions had a similar trend at all loads but with a significant reduction for CR 18:1. Addition of DEE escalated the NOx emissions by 4% to 6% as the compression ratio was increased from 17:1 to 18:1. Smoke emission reduced significantly with oxygenated fuel blends but showcased an increasing trend with the increase in compression ratios. The in-cylinder pressure variation and heat release analysis were also improved for oxygenated diesel-biodiesel blends.