Investigations on premixed charge compression ignition type combustion using butanol-diesel blends

Renewable biodegradable butanol blended to diesel fuel was used in an engine that operates on PCCI mode shows excellent combustion characteristics and offer efficient high load performance with minimum exhaust emissions. Its higher octane number prevents engine knock, higher cooling effects have potential to reduce the NOX emissions and well-mixing ability with air substantially reduces the smoke emission. In the present experimentation, n-butanol and diesel blend B10, B20, B30 and B40 were tested on PCCI mode which was mainly accomplished by DI timing 20 degree CA bTDC and injection pressure 400 bar. For high load operation, B40 blend provided 6.9%, 8.1%, 12.9% and 13.7% higher brake thermal efficiency over B30, B20, B10 and neat diesel respectively at the cost of small increment in brake specific fuel consumptions. Smoke and CO emissions reduction were observed. However, NO and HC emissions produced were higher than the B30, B20, B10 and diesel respectively. Considering the benefits in terms of higher high load efficiency and lower emissions, in addition, delayed CA50 (50% burn at crank angle) than all fuel blends, B40 blend was preferred for higher premixing to attain higher performance.