Identification of optimum Calophyllum inophyllum bio-fuel blend in diesel engine using advanced vibration analysis technique

Bio-fuel causes less pollution to the environment as compared with diesel fuel. However, sound and vibration resulting from the combustion in bio-fuel-powered engines adversely affect users. In this study, non-edible bio-fuel, i.e., Calophyllum inophyllum, and its blends were investigated for their performance as alternative fuel and were compared by using vibration as the engine parameter. Previous studies used overall engine vibration to determine the optimum bio-fuel blends with minimal vibration. Overall vibration could consist of vibration components due to combustion as well as other external vibration sources. This condition limits its effectiveness in identifying an optimum fuel blend mainly due to vibration caused by combustion effect. Advanced vibration analysis technique, which consists of time-domain, frequency-domain, and motion visualization analyses (i.e., operating deflection shape analysis), is first performed to isolate the effect of external vibration source due to torque from the overall vibration. Bio-fuel-powered engines at full speed and with the lowest engine torque are more suitable for the identification of an optimum fuel blend with minimal engine vibration. Bio-fuel blend B20 has the least vibration in overall root mean square acceleration at full speed compared with pure diesel and other bio-fuel blends.