FUEL, vol.223, pp.53-62, 2018 (SCI-Expanded)
In this experimental study, the usage of high bioethanol proportion in the different types of biodiesel-diesel blends were carried out to discover the effects of the high bioethanol proportion on the injection, combustion, performance and emission parameters of a common rail diesel injection (CRDI) engine with two stage injection (TSI) strategy under different engine loads. The TSI strategy consisted of two stage direct injection into the cylinder as a pilot and main injection. The bioethanol (BE) was produced used wastes originated from sugar production process, animal-based (AB) biodiesel was originated from waste fleshing oil and the vegetable based (VB) biodiesel was obtained from safflower-canola oil mixture. Pure diesel fuel (DF), three AB ternary blends (bioethanol-diesel-animal based biodiesel), and three VB ternary blends (bioethanol-diesel-vegetable based biodiesel) were determined as test fuels. Bioethanol ratios were 25% and 35% by mass in the AB and VB ternary blends, while biodiesel concentration was fixed to be 20% by mass. It was found that the maximum cylinder gas pressure (P-max) of the VB ternary blends observed higher than that of AB ternary blends and DF at high loads, while the P-max decreased by usage of AB and VB ternary blends at low and medium load conditions. Longer ignition delay (ID), higher thermal efficiency, lower maximum pressure rise rate (MPRR) values were observed by usage of the higher percentage of bioethanol (35 by mass%) in the AB and VB ternary blends at medium and high load conditions. AB ternary blends were more effective than the VB ternary blends on the reduction in total hydrocarbon (THC) emission, while carbon monoxide (CO) emissions increased with the increase in bioethanol content in the AB and VB ternary blends at low and high load conditions. Nitrogen oxides (NOx) and smoke emissions can be decreased by usage of high bioethanol proportion in the blends at high load conditions, simultaneously. The combustion and emission results showed that the usage of ternary blends with TSI strategy contributed to the elimination of the negative effects of the high bioethanol content.