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Öğe Effects of isopropanol-butanol-ethanol (IBE) on combustion characteristics of a RCCI engine fueled by biodiesel fuel(Journals & Books, 2021-10) Altun, Şehmus; Okcu, Mutlu; Varol, Yasin; Fırat, MüjdatThe reactivity controlled compression ignition (RCCI) strategy using fuels with different reactivity’s has attracted attention due to its high thermal efficiency as well as very low NOx and PM emissions in comparison to conventional combustion. As previous studies have shown that the type and amount of low reactivity fuel have a significant contribution to the in-cylinder reactivity, thus RCCI combustion, in this study, Iso-Propanol-Butanol-Ethanol (IBE), which has comparable characteristics to n-butanol and ethanol, is employed as low reactivity fuel (LRF) in a RCCI engine fueled by petroleum based EN590 fuel and commercial biodiesel. The IBE mixture was in volumetric ratios of 3:6:1 as in the fermentation process of butanol, that is to say; 30% Iso-Propanol, 60% Butanol and 10% Ethanol. In each experimental condition, keeping the total energy of the fuel supplied to the engine in conventional combustion mode for each cycle as constant, the premixed ratio (Rp) in case RCCI combustion was applied as 0%, 15%, 30%, 45% and 60% (the amount of LRF in energy basis) over this energy amount. The effect of premixed ratio of IBE on combustion characteristics were investigated in a single-cylinder RCCI engine under different loads with using both petroleum diesel and biodiesel as high-reactivity fuels (HRF), respectively. According to experimental results, a higher in-cylinder pressure was measured by using diesel in both conventional and RCCI mode compared to the use of biodiesel. Considering the peak in-cylinder pressure and rate of heat release, the premixed ratio (Rp) of up to 45% was found as optimum for all loads while it was up to 30%Rp for the NOx emissions. In addition, the biodiesel-fueled RCCI engine produced the lowest smoke opacity in all loads and it gradually decreased by up to 97% with the application of the RCCI strategy. Furthermore, the results showed that a simultaneous reduction in NOx and smoke opacity could be obtained under 60% load and up to 30% Rp with a marginal increase in unburned HC emissions.Öğe Combustion, performance, and emissions of safflower biodiesel with dimethyl ether addition in a power generator diesel engine(Taylor & Francis, 2020-04-29) Aydın, Hüseyin; Işık, Mehmet Zerrakki; İşcan, Bahattin; Topkaya, HüsnaIn this study, the effect of dimethyl ether (DME) addition to diesel (ultralow sulfur diesel fuel) and biodiesel fuels on the combustion, performance, and emissions of a diesel-powered generator was investigated. For this purpose, fuel samples of the ternary blend that volumetrically composed of 10% safflower biodiesel–10% dimethyl ether–80% ultralow sulfur diesel fuel (B10DME10), the ternary blend that volumetrically composed of 25% safflower biodiesel–25% dimethyl ether–50% ultralow sulfur diesel fuel (B25DME25), the binary blend that volumetrically composed of 25% safflower biodiesel–75% ultralow sulfur diesel fuel (B10DME10) B25, and pure safflower oil biodiesel (B100) and standard ultralow sulfur diesel (D2) were prepared. The test engine was loaded by power drawing from the generator by the usage of equivalent powered electrical heating resistances. Generally, using DME with biodiesel improved the combustion properties of biodiesel blends that can be attributed to the lower viscosity of DME. The maximum cylinder pressure was obtained for B10DME10 in general and sometimes for B25DME25. When test fuels are compared, DME blends showed higher and earlier peaks of heat release compared to diesel and biodiesel blend fuels especially. It was found that combustion is more efficient from mass fuel consumption (MFC) and brake specific fuel consumption (BSFC) values in the use of DME than biodiesel. BSEC values of using DME in the blends considerably decreased that it is the proof of improved combustion and energy efficiency. The highest average efficiency values were obtained for B25DME25 as 28.3% although it has a lower calorific value than D2 due to the considerably improved combustion properties of DME, while the average efficiency values were 23.1%, 23.3%, and 20.7% for D2, B25, and B100 fuels, respectively. Highest carbon monoxide (CO) emissions were obtained in the use of pure biodiesel, while the lowest CO emissions were obtained in the use of DME. The addition of DME is seen to increase the nitrogen oxides (NOx) and CO emissions.
