A comprehensive assessment on performance behavior of a CI engine using bio oil emulsions (PJSO10, KSO10 and CSO10) as fuels

This paper aims at evaluating the performance of bio oils obtained from pyrolysis of three different biomass (namely Prosopis Juliflora seeds-PJS, Coconut shell-CS and Kiker seeds-KS) as fuels in a compression ignition engine. A single cylinder diesel engine developing a power output of 3.7 kW at 1500 rpm was used. A comparative study was made on the engine's performance, emission and combustion behavior of three bio oils by converting them into their emulsions. Bio oil emulsions (namely PJSO10-Prosopis Juliflora emulsion, CSO10-Coconut shell emulsion and KSO10-Kiker seed emulsion) were prepared by mixing 10% of bio oils in the presence of 3% of a surfactant (span 80) with 87% of diesel by volume. Emulsions were tested in a single cylinder diesel engine for their performance as fuel. Engine test results showed comparable performance with all the emulsions of bio oil as compared to BD (Base diesel). CSO10 indicated the brake thermal efficiency very close to BD at all power outputs among the tested emulsions. Considerable reduction in smoke and NOx emissions were observed with all the emulsions of bio oil as compared to BD at all power outputs. Cylinder peak pressure and maximum rate of pressure rise indicated close values to BD at all power outputs with all the emulsions. Ignition delay was found as higher with all the tested emulsions as compared to BD at all power outputs. From the experimental findings it was concluded that bio oils obtained from Prosopis Juliflora seeds-PJS, Coconut shell-CS and Kiker seeds-KS can be used upto 10% by volume (without any modifications in the engine) as partial replacement of diesel by making emulsions with diesel with comparable performance and considerable reduction in smoke and NOx emissions. Among the emulsions the best choice can be CSO10 for better thermal efficiency and reduced emissions.