Impact of Carbon Nanotubes and Di-Ethyl Ether as additives with biodiesel emulsion fuels in a diesel engine – An experimental investigation

Abstract In the current global energy scenario, fossil fuels face challenges with regards to exorbitant demand, environmental hazards and escalating costs. In this regard, the technical community is in quest for alternative resources. In this context, biodiesel fuel is potentially considered as alternative fuels for compression ignition engines. Hence, in this current investigation, biodiesel and biodiesel emulsions are prepared from a vegetable oil and further subjected for the blending with potential additives such as CNT (Carbon Nanotubes) and DEE (Di-Ethyl Ether) to improve the working attributes of the diesel engine. The entire investigation was carried out in five stages. In the first stage, both pure diesel and biodiesel (derived from jatropha oil) fuels were tested in the diesel engine to obtain baseline readings. In the second stage, water–biodiesel emulsion fuel was prepared in the proportion of 91% of biodiesel, 5% of water and 4% of emulsifiers (by volume). In the third stage, 50 ppm of CNT, 50 ml of DEE and combined mixture of CNT+DEE (50 ppm CNT+50 ml DEE) were mixed with the water–biodiesel emulsion fuel separately to prepare the CNT and DEE blended water–biodiesel emulsion fuels respectively. In fourth stage, the prepared emulsion fuels were subjected to stability investigations. In the fifth stage, all the prepared stable emulsion fuels were subjected for experimental testing in a diesel engine. It was observed that the CNT and DEE blended biodiesel emulsion fuels reflected better performance, emission and combustion attributes than that of pure diesel and biodiesel. At the full load, the brake thermal efficiency, NO and smoke emission of CNT+DEE fuels was 28.8%, 895 ppm and 36%, whereas it was 25.2%, 1340 ppm and 71% for pure diesel respectively. It was also observed that on adding CNT and DEE with the biodiesel emulsion fuels, the ignition delay was shortened and henceforth, the additive blended biodiesel emulsion fuels exhibited higher brake thermal efficiency and reduced emissions (NO, smoke) than that of pure diesel and biodiesel.