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Nigella sativa is one such plant species indigenous to Middle-east, Eastern Europe, and the Asian Subcontinent. Black cumin seeds derived from N. sativa are one of the identified biomasses to produce biodiesels for the use in an unmodified CI engine. The current study aims to evaluate the credibility of Nigella sativa methyl ester (NSME) as a suitable blend alongside mineral diesel in a common rail direct Injection engine via fundamental combustion analysis. In the present work, 20% of Nigella sativa methyl ester has been tested in diesel engine at 600 bar injection pressure under different pilot and main injection forms. The pilot injection mass has been varied from 5–15% along with variation in main injection also. An optimized injection strategy has been found with respect to performance and emissions for effective implementation of EGR at 10% and 20% rate. At 5% pilot injection, the NSME20 fuel showed comparable brake thermal efficiency and brake-specific fuel consumption at all engine loads. Furthermore, NOx emission of NSME20 fuel has been reduced by increasing the pilot injection rate when compared to diesel and this has been further reduced with 10–20% exhaust gas recirculation. On the other hand, the combustion characteristics of NSME20 blend also shown similar pattern like diesel fuel with slight reduction in cylinder pressure and heat release rate. Finally, it has been concluded that the newly developed Nigella sativa methyl ester can be used as sustainable biofuel for various energy applications in the present scenario. [Figure not available: see fulltext.].

Calophyllum inophyllum biodiesel is seems to be a potential alternative fuel for diesel engine applications due to its non-edible form, easily cultivable nature and abundant availability everywhere in the world. Isobutanol is the next generation biofuel which can be used as partial substitute to petroleum diesel or biodiesel due to its better solvency character. In the present study, a comparative assessment on diesel engine characteristics is carried out using isobutanol as an additive with diesel and biodiesel in the form of binary and ternary blends. Five blends are prepared by 20% of isobutanol with diesel and biodiesel as D80IB20 and B80IB20 along with three ternary blends of diesel-biodiesel-isobutanol using 10%, 15% and 20% concentrations of isobutanol. Experimental study in a diesel engine revealed that the brake thermal efficiency is improved by 3.19% for 10% isobutanol addition in diesel-biodiesel blends with significant improvement in brake specific fuel consumption when compared to biodiesel. All binary and ternary blends of isobutanol reduce CO emission by 13–59% than that of diesel fuel with substantial penalty in HC emission. Meanwhile, when compared to biodiesel, the oxides of nitrogen emission is decreased by 8.16% for isobutanol addition with diesel and biodiesel in terms of binary and ternary blends but higher than that of conventional diesel fuel. Furthermore, momentous improvement is observed in heat release rate during isobutanol addition for B80IB20, D70B10IB20, D70B15IB15 and D70B20IB10 fuel blends when compared to pure biodiesel. Finally, it is noted that isobutanol would be a feasible additive for the partial replacement of diesel and biodiesel in the blends for diesel engine applications.

Biodiesel can serve as possible alternate fuels in compression ignition engine as it leads to an effective reduction in consumption of fossil fuels. Moreover, it has been observed that biodiesel has the potential to reduce most exhaust emissions. The aim of the present study is to investigate the effect of n-octanol with Calophyllum Inophyllum biodiesel on compression ignition engine characteristics. Five different fuel blends are prepared by varying the concentration of n-octanol from 10% to 50% on a volume basis. It has been observed that the addition of n-octanol with biodiesel decreases the calorific value due to its inherent oxygen content. A mixed 6 × 5 level full factorial design with 3 replications was used for conducting the experiment. The statistical test by analysis of variance (ANOVA) revealed that CIME blend has the greater influence, contributing 71.3% to HC emission. The engine load has greatest influence of 98.88% to BTE followed by 98.77% to NOx, 95.74% to CO and 75% to peak pressure. The experimental results showed that the increase of n-octanol fraction in blends prolonged the ignition delay generating higher peaks of in-cylinder pressure and heat release rates during the premixed mode of combustion. Brake thermal efficiency has improved with the increase of n-octanol fraction up to 30% and then started decreasing with further increase of n-octanol in blends. Brake specific fuel consumption has reduced by about 20% with the increase of n-octanol fraction by 50%. Furthermore, the cooling effect produced by a lower fraction of n-octanol in the blend reduces the in-cylinder temperature resulting in lower NOx emissions. However, the poor ignition and evaporation characteristics of n-octanol has resulted in increase of CO and smoke emissions. HC emissions increase with the increase of n-octanol percentage due to the overleaning effect of the excess oxygen content in the n-octanol. The higher fractions of n-octanol is beneficial in lowering the CO and

In the present work, spray characteristics of Lemon Peel Oil (LPO) were studied to check its suitability in the direct injection spark ignition engine. From the fuel properties, it was observed that LPO has superior calorific value and comparable octane rating compared to the conventional biofuels, i.e., alcohols. Experiments were performed in a constant volume spray chamber under different engine like pressure and temperature conditions. A six-hole GDI injector was used to study the spray behavior of LPO and then compared to standard reference fuel, isooctane. The ambient conditions in the chamber were derived using the crank resolved pressure data of the GDI engine. The selected chamber conditions are a) 1.5 bar, 329 K; b) 2.5 bar, 371 K; c) 6.0 bar, 453 K. Three parameters,i.e., liquid penetration length, spray cone angle, and droplet distribution was studied to understand fuel spray behavior. Mie-scattering technique was used to determine liquidpenetration,and cone angle the droplet size distribution was measured using the Phase Doppler Particle Analyzer (PDPA).Results showed that ambient pressure and temperature have a significant effect on spray behavior for both the selected fuels. The spray penetrationwas decreasedwith an increasein pressureand temperature. Both LPO and isooctane showed better droplet evaporation at higher pressure and temperature conditions.

This work presents the effect of the ternary oxygenated additive on diesel biodiesel blended fuel to evaluate the engine characteristics. The Calophyllum inophyllum trees being abundant in India can lessen the dependence on petroleum imports to a specific extent. Methyl tertiary butyl ether is used as an oxygenated additive for the ternary blends preparation as 5-20% by volume. Seven blends of neat baseline diesel, biodiesel (Calophyllum inophyllum Methyl Ester), a blend of diesel (50%)-biodiesel (50%), a blend of diesel (50%)-biodiesel-methyl tert-butyl ether (5, 10, 15, and 20%) are prepared which are tested on a single cylinder, constant speed diesel engine. The experimental results were revealed that the replacement of biodiesel by MTBE has shown a slight reduction in brake thermal efficiency with a slight increase in brake-specific fuel consumption. Further, the MTBE addition in ternary blends reduced the unburned hydrocarbon, CO, and NOx by 63.9, 6.4, and 3.37% respectively. In addition, the carbon dioxide emission is almost similar to diesel fuel at a higher addition of MTBE with diesel-biodiesel blend. In the combustion point of view, the addition of 5% MTBE resulted in 3.49 and 5.1% reduction of peak pressure and heat release rate are observed as compared to diesel fuel. Critical analysis in combustion aspects is also carried out and it is witnessed with prolonged ignition delay during MTBE addition with diesel-biodiesel blends.

Lemon peel oil is one of the renewable and biodegradable biofuel for diesel engine applications due to its low viscous nature. This study aims to observe the performance and emission characteristics of a common rail direct injection diesel engine at various fuel injection strategies under different loading conditions. An open type electronic control unit is used to control the fuel injection timing, injection rate and split injection at various injection pressures. In this research work, 20% lemon peel oil-diesel blend (by volume) is injected at a pressure of 400 bar, 500 bar and 600 bar with 10% pilot injection by volume and the results are compared with diesel fuel at same injection conditions. Further, pilot injection quantity of lemon peel oil blend is varied by 20% and 30% of total volume of fuel injected at 600 bar injection pressure. Finally, the experimental work is carried out in common rail direct injection diesel engine fuelled with lemon peel oil blend under 10% cooled exhaust gas recirculation condition. The study reveals that the brake thermal efficiency is improved with increase in injection pressures and pilot injection rates. However, this trend has been changed during 10% EGR addition for lemon peel oil blend operation at 30% pilot injection rate. The combustion characteristics are improved for lemon peel oil blend for 600 bar injection pressure with 20% and 30% pilot injection rates compared to 10% pilot injection rate. The higher pilot injection rate has shown significant reductions in carbon monoxide, hydrocarbon and smoke emissions. However, the emission results are reversed with 10% exhaust gas recirculation at 600 bar injection pressure of lemon peel oil blend. There is a significant reduction in NOx emission for low injection pressure of lemon peel oil blend at 10% pilot injection rate.

Lemon peel oil (LPO) is considered to be a viable alternative fuel for diesel engine applications due to its wider availability, renewable nature, easy extraction process, almost equivalent calorific value as neat diesel, and low viscosity. The present work aims to investigate the effect of novel emulsified LPO in a diesel engine in order to reduce the NOx emission without compromising the engine performance. A new ionic surfactant is introduced in the present study, namely methyl-dihydroxy propyl imidazolium chloride due to its higher hydrophilic-lipophilic balance value which helps to prepare stable water in oil emulsion. Also, Span 80 has been selected as another suitable surfactant for water in oil emulsion. Four emulsified fuel samples have been prepared using LPO, water, and different concentrations of surfactants. All the fuel samples are tested for their stability through gravitational technique for 7 days. Among the emulsified samples, 92% LPO + 5% water + 2% Span 80 + 1% methyl-dihydroxy propyl imidazolium chloride by volume (LPOE2) and 93.5% LPO + 5% water + 1.5% surfactant Span 80 by volume (LPOE4) have showed better stability when compared to other emulsion fuel samples. It is also revealed that the stability of LPO emulsion is improved by the addition of two emulsions. The experimental results showed that the brake thermal efficiency of LPO emulsion is reduced to 29.87 from 34.58% of pure LPO at full load condition. Oxides of nitrogen emission and smoke emission are reduced by 21–32 and 6–15% for the LPO emulsion samples compared to pure LPO. Moreover, the diesel engine operation with emulsified form of LPO increases the HC emission about 0.1 g/kWh for LPOE4 and 0.15 g/kWh for LPOE2 fuels from 0.053 g/kW for pure LPO at maximum power output condition. The reformulation of LPO into emulsified form increases the CO emission by 25–53% compared to pure LPO. Moreover, the reformulation of LPO into emulsions has resulted in lower cylinder pressure and heat r