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According to the literature, there is in lack of a comprehensive study to compare the combustion, performance and emissions of a diesel engine using diesel, biodiesel and ethanol fuels (DBE) in the blended mode and fumigation mode under various engine speeds. This study was conducted to fill this knowledge gap by comparing the effect of blended, fumigation and combined fumigation + blended (F + B) modes on the combustion, performance and emissions of a diesel engine under a constant engine load (50% of full torque) with five engine speeds ranging from 1400 rpm to 2200 rpm. A constant overall fuel composition of 80% diesel, 5% biodiesel and 15% ethanol, by volume % (D80B5E15), was utilized to provide the same fuel for comparing the three fueling modes. According to the average results of five engine speeds, the blended mode has higher peak heat release rate (HRR), ignition delay (ID), brake thermal efficiency (BTE), brake specific nitrogen monoxide (BSNO) and brake specific nitrogen oxides (BSNO X), but lower duration of combustion (DOC), brake specific fuel consumption (BSFC), brake specific carbon dioxide (BSCO 2), brake specific carbon monoxide (BSCO), brake specific hydrocarbon (BSHC), brake specific nitrogen dioxide (BSNO 2), brake specific particulate matter (BSPM), total number concentration (TNC) and geometric mean diameter (GMD), and similar peak in-cylinder pressure compared to the fumigation mode. In addition, for almost all the parameters, results obtained in the F + B mode are in between those of the blended and fumigation modes. In regard to the effect of engine speed, the results reveal that the increase in engine speed causes reduction in peak in-cylinder pressure, BTE, BSHC, BSNO X , BSNO and BSNO 2 , but increase in peak HRR, ID, DOC, BSFC, BSCO 2 , BSPM and TNC, and similar BSCO and GMD for almost all the tested fueling modes. It can be inferred that the blended mode is the suitable fueling mode, compared with the fumigation mode, under the operating conditions investigated in this study. • Blended and fumigation modes are compared at various diesel engine speeds. • D80B5E15 was used as a fuel for both blended and fumigation modes. • Blended mode is the suitable fueling mode. • Fumigation mode shows the worst engine performance and emissions. • Fumigation + blended mode has effects in between the fumigation and blended modes. [ABSTRACT FROM AUTHOR]

Abstract This experimental study was conducted to explore the favorable and unfavorable conditions which promote or reduce the performance and emissions in a diesel engine, based on six engine loads (5% to 95% load) and five biodiesel contents including B0 (0% waste cooking oil biodiesel and 100% diesel, by volume %), B20, B50, B75 and B100 (pure biodiesel), at a constant engine speed of 1920 rpm. According to the results, the maximum brake specific fuel consumption was recorded at the lowest engine load (5% load) using B100; while the highest brake thermal efficiency was obtained at 80% load for B100. In regard to regulated emissions, the highest engine load (95% load) with diesel fuel was the condition for the formation of maximum CO, smoke opacity, PM mass, total particle number concentration and geometric mean diameter. The 95% load with B100 was the condition for maximum CO 2 and NO X. The 60% load with diesel fuel was the condition for maximum THC. For unregulated emissions, low engine load with B100 was the condition for maximum formaldehyde, acetaldehyde, ethene and propene. The maximum 1,3-butadiene was observed for B100 at 80% load. The highest benzene emission was recorded at 40% load for B100. The maximum toluene and xylene emissions were found at 5% load for diesel fuel. In addition, the conditions which lead to produce the minimum emissions are also extensively discussed in the present study. Graphical abstract Unlabelled Image Highlights • Effects of engine load and biodiesel on engine emissions were analyzed. • Tests were conducted on six engine loads and five biodiesel contents. • Contour-plot maps were applied for investigation. • The best and worst conditions for performance and emissions were explored. • Contour-plot maps were divided into nine regions to find best and worst conditions. [ABSTRACT FROM AUTHOR]

Highlights • Performances of diesel engine in blended and fumigation modes are compared. • Diesel-biodiesel-ethanol was used as a fuel for both blended and fumigation modes. • Blended mode gives the highest engine performance and lowest emissions. • Fumigation mode gives the worst engine performance and emissions. • A combined fumigation and blended mode (F + B) of fueling is introduced. Abstract The present study aimed to compare the combustion, performance and emissions of a diesel engine fueled with diesel, biodiesel and ethanol in the blended and fumigation modes. In addition, a combined fumigation and blended mode (F + B) of fueling was introduced to understand its behavior in comparison with the blended and fumigation modes. In the blended mode, the fuel was composed of 80% diesel, 5% biodiesel and 15% ethanol (DBE), by volume. In the fumigation mode, a mixture of biodiesel and ethanol (BE) was injected into the intake manifold and diesel fuel was used as the main fuel. In the F + B mode, half of the BE mixture was injected into the intake manifold and another half of the DB mixture was mixed with diesel to form the main fuel. The experiments were conducted at a speed of 1800 rpm with five engine loads at a constant mixture percentage of D80B5E15 for the three fueling modes to provide the same fuel composition for comparing the effects of the three fueling modes. According to the average of five loads, compared to the pure diesel operation, the blended mode causes increases in peak heat release rate (HRR), ignition delay (ID), BSFC, CO, HC and NO 2 ; drops in duration of combustion (DOC), CO 2 , NO X , PM, total number concentration (TNC) and geometric mean diameter (GMD); and similar peak in-cylinder pressure and BTE. While the fumigation mode leads to higher peak HRR, DOC, BSFC, CO, HC, NO 2 and TNC; lower ID, BTE and NO X ; and similar peak in-cylinder pressure, CO 2 , PM and GMD in comparison with the diesel mode. In addition, the F + B mode has the effects between those of the fumigation and blended modes. Among the three fueling modes, the blended mode gives the highest engine performance and lowest emissions, except for NO X. In contrast, the fumigation mode gives the worst engine performance and emissions, except for NO X. [ABSTRACT FROM AUTHOR]

This experimental study is conducted to investigate the combustion, performance and emissions of a diesel engine fueled with different alternative fuels under five engine loads and at an engine speed of 1800 rpm. Seven fuels, including diesel (D), waste cooking oil biodiesel (B), methanol (M), ethanol (E), 2-propanol (Pr), n-butanol (Bu) and n-pentanol (Pe)) were used to produce six blended fuels, labelled as DB, DBM, DBE, DBPr, DBBu and DBPe. Each blended fuel has the same oxygen content of 5.0% and very close carbon and hydrogen contents and LHV. According to the average results of five loads, the blended fuels in general cause to (a) increases in peak HRR (except DB), ignition delay (except DB), COV IMEP (except DBM), COV Max(dP/dθ) (except DB and DBM) and BSFC; (b) slight decrease in duration of combustion (except DB); and (c) similar peak in-cylinder pressure and BTE (except DBM and DBBu) compared to diesel fuel. Moreover, all the blended fuels lead to reductions in CO 2 (except DB), CO, HC, NO X (except DB), PM, total number concentration (except DBPr) and geometric mean diameter, compared to diesel fuel. Overall, DBM shows the highest BTE, the lowest BSFC, and the lowest CO 2 , CO, HC, PM, NO X (after DBPr), COV IMEP and COV Max(dP/dθ) (after DB), while DB has the lowest influence, among all the tested blended fuels. [ABSTRACT FROM AUTHOR]