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The applications and development of biodiesel fuels are restricted by the poor low-temperature fluidity and oxidation stability. Meanwhile, typical antioxidants are usually compounds containing phenyl groups, which have the disadvantages of high toxicity and carcinogenicity. To address these defects, our study originally synthesized a multifunctional additive using both post grafting and nanocomposite technology, as well as apply a biofuel antioxidant free of benzene ring group, 4-Amino-2,2,6,6-tetramethylpiperidine. Our findings reveal that the delayed crystallization behavior of B20 (20 vol%. biodiesel +80 vol%. diesel) is strongly dependent on the additive structure and amount, which the pour point (PP) and cold filter plugging point (CFPP) are decreased by 20 and 16 °C respectively at 1000 ppm. The post grafting technology enhanced additive antioxidant properties, which extend the induction period of B20 from 2.0 to 6.9 h. Our study confirmed the synthesized additives through possess synergistic enhancement effects on both cold flow properties and oxidation stability. In addition, DFT calculations simulating the potential energy changes of B20 solutions forecast copolymer structure affects the low-temperature fluidity. Hence this study pioneered the proposal for developing multifunctional additives through both post grafting and nanocomposite technology of methacrylate copolymer for biofuels, and provide a theoretical prediction strategy for exploring optimum copolymer pour point depressant for fuels. [Display omitted] • A novel copolymer nanocomposite was prepared as a multifunctional additive for fuels. • The oxidation induction time of treated B20 is increased from 2.0 to 6.9 h. • The pour point and cold filter plugging point are decreased by 20 and 16 °C, respectively. • DFT calculations reveal the copolymer structure affected the cold flow properties. • The nanocomposite additives exhibit synergistic enhancement on the drawbacks of B20. [ABSTRACT FROM AUTHOR]

Optimizing the operational parameters of the photosynthetic process is essential for effective microalgae-based CO 2 capture and fixation. This study develops and validates models that can relate the effects of CO 2 concentration and aeration rate on relevant microalgal properties, including biomass productivity and CO 2 biofixation rate. The maximum biomass concentration was predicted as 2.80 g⋅L−1 at the optimal CO 2 concentration of 10.2 % and aeration rate of 0.55 vvm. Based on the proposed models, the CO 2 biofixation rate characterized by carbon content in dry microalgal cells, and the timings of microalgae entering the exponential growth and stationary growth phases were effectively predicted. Furthermore, the lower heating value of harvested microalgal biomass was up to 21.98 kJ⋅g−1 and the dominant fatty acid methyl esters (FAME) species were C16 – C18, highlighting the potential of Chlorella vulgaris as the feedstock for microalgae-based energy production. Consequently, microalgae present a remarkable dual function for CO 2 mitigation and renewable bioenergy production. [Display omitted] • Models simulating microalgal growth and CO 2 fixation rate were developed. • Optimal CO 2 concentration and aeration rate for cell growth were determined. • High biomass of 2.80 g L−1 was achieved at the optimal operational condition. • Chlorella shows high potential on production of combustion fuel and biodiesel. [ABSTRACT FROM AUTHOR]

Carbon footprint indicates the total amount of greenhouse gases released into the atmosphere by individuals, institutions and countries. The widespread use of fossil fuels is a big player which increases the carbon footprint. Therefore, switching to sustainable alternatives in energy production and consumption is an effective step in combating climate change, as well as efforts to prevent the depletion of fossil fuels. In this regard, although biodiesels offer a solution to the depletion of fossil fuels, with this advantage, the effects of production processes and use on environmental sustainability should be taken into consideration. Many scientific studies have shown that engine performance remains below standards with biodiesel. The availability of hydrogen as an energy carrier in cylinder to overcome the above-mentioned negative situations has recently become a popular topic for fuel researchers. In this work, the diesel-biodiesel fuels were blended proportionally and tested on a three-cylinder water-cooled in-direct diesel engine at varying loads (15, 30, 45, and 60 Nm) and a constant engine speed of 2200 rpm for observing the effects of test fuels on combustion, performance, and emissions characteristics of diesel engine. First of all, conventional diesel fuel (D) was used to obtain reference data, and then B20 fuel obtained by mixing waste cooking oil with 20 % by volume of diesel fuel was used. The remaining 4 fuels are test fuels obtained by giving hydrogen from the intake manifold at different flow rates (10, 20, 30, and 40 L/min) in addition to B20 fuel. These fuels are called B20 + 10 Lpm H 2 , B20 + 20 Lpm H 2 , B20 + 30 Lpm H 2 and B20 + 40 Lpm H 2 , respectively. As a result, the BSFC of B20 fuel increased by 8.78 % compared to diesel fuel, and then the addition of hydrogen dropped the BSFC value by 8.8 %, 13.02 %, 17.16 %, and 22.12 % for B20 + 10 Lpm H 2 , B20 + 20 Lpm H 2 , B20 + 30 Lpm H 2 , and B20 + 40 Lpm H 2 , respectively. Hydrogen enrichment also had a positive impact on BTE. Although the BTE dropped by 6.14 % in B20 fuel compared to diesel, it increased by 4.51 %, 5.05 %, 5.62 %, and 7.12 % in B20 + 10 Lpm H 2 , B20 + 20 Lpm H 2 , B20 + 30 Lpm H 2 and B20 + 40 Lpm H 2 fuels, respectively. The addition of 10, 20, 30, and 40 Lpm H 2 to B20 fuel reduced NOx emissions by 31.25 %, 33.08 %, 38.87 %, and 41.46 %, respectively, and also reduced CO emissions by 17.47 %, 30.73 %, 51.8 % and 59.04 % respectively. • Detailed combustion, performance, and emission characteristics of in-direct CI engine. • Combustion temperature increased as the hydrogen volume increased due to its high calorific value. • Deteriorating engine performances resulting from the use of biodiesel were improved with hydrogen. • At the engine load of 60 Nm, the engine performance worsened for all test fuels due to deterioration of air fuel ratio. [ABSTRACT FROM AUTHOR]

The oxygenated additives can improve the physical properties of biodiesel blends to achieve enhanced characteristics of a diesel engine. The present work has investigated ethylene glycol monoacetate (EGM) and tri-ethylene glycol mono-methyl ether (TGME) as potential additives for the jatropha-karanja dual blended biodiesel for improved characteristics of diesel engines. The experiments have been conducted with a single cylinder four stroke diesel engine operating at constant speed of 1500 rpm. The performance, emission and combustion parameters of the engine were investigated with pure diesel, jatropha-karanja dual blended biodiesel having 20 % of methyl ester and the biodiesel added with 2, 4, and 6 % of both the additives respectively. The doping of additives improved the brake thermal efficiency by 4.1 and 4.7 % with brake specific fuel consumption dropped by 0.18 and 0.2 kg/kWh. The additives reduced the hydrocarbon emission by 29.8 % and carbon monoxide by 40 % with a slight increase in NOx emission by 5.2 %. The cylinder pressure attained value near to pure diesel while the heat release rate increased by 12.6 % indicating proper fuel combustion inside the engine cylinder. Thus, the oxygenated additives can suitably be adopted as performance improvers in biodiesel fuels for automotive engines. • EGM and TGME have been used as additive with jatropha karanja dual blended biodiesel. • The biodiesel properties improved with the addition of both the additives. • Enhanced combustion characteristics were achieved by adding the oxygenated additives upto 6 % by volume. • The inclusion of additives improved the engine performance with increased BTE and reduced BSFC. • The HC and CO emission reduced with increase in content of both the additives with slight increase in NOx emission [ABSTRACT FROM AUTHOR]

The natural gas (NG) stratified premixed combustion mode (NSPC) demonstrates significant potential for improving thermal efficiency and lowering emissions when compared to the NG mixing-limited combustion mode (NMLC). In this study, the NSPC for a NG/biodiesel dual direct injection engine was optimized through numerical simulation. The initial evaluation of biodiesel as the pilot fuel reveals its capacity to reduce soot and CO emissions while simultaneously increasing thermal efficiency in comparison with pure diesel. The subsequent examination delved into the effects of the injection timing of biodiesel and natural gas on mixture distribution, combustion, and emissions characteristics. The findings indicates that a well-balanced combination of moderate injection timing of natural gas and slightly delayed injection timing of biodiesel results in significantly lowered CO and soot emissions while maintaining high thermal efficiency, but with a trade-off of increased NO x emissions. The engine performance was further refined through the integrated application of exhaust gas recirculation (EGR) and pilot fuel pre-injection. Achieving a high thermal efficiency of 42.5%, minimal CO emissions at 1.5 g/kWh, soot emissions below 1 × 10−4 g/kWh, and NOx emissions less than 2 g/kWh, is achieved by configuring the start of injection for natural gas and biodiesel at −56°CA ATDC and −10°CA ATDC, respectively, with a biodiesel pre-injection ratio of 30%, and an EGR rate of 36%. • Benefits of biodiesel as a pilot fuel for igniting stratified premixed natural gas were explored. • Fuel injection timing was optimized to improve both engine performance and emissions. • EGR and pilot fuel pre-injection ensured enhanced engine performance without sacrificing NOx. [ABSTRACT FROM AUTHOR]

Researchers have constantly been looking for renewable alternative fuels due to high fuel price volatility, energy security concerns, and produced harmful emissions. One of the promising alternatives is to produce biodiesel from waste economical feedstock such as chicken fat. Esterification and transesterification are used to create methyl ester from chicken fat. Then, 25%, 50%, 75%, and 100% of chicken oil biodiesel are volumetrically blended with diesel fuel. Diesel engine is loaded between 0% and 100% at 3000 rpm rated speed. Exergetic and exergoeconomic assessments of diesel engine fuelling with blends of chicken biodiesel were conducted in the present study. Diesel oil performed most efficiently in terms of exergy. For B100, the worst exergetic results are attained. The exergy efficiency of test engine at 75% engine load was 33.25% for the D100 and 27.85% for the B100. D100 produced the best exergoeconomic findings, while adding biodiesel to D100 made the exergoeconomic parameters worse. Crankshaft work had a particular exergy cost of 110.02 $/GJ for D100 and 194.37 $/GJ for B100 at 75% of engine output power. In the conclusion, it is noted that the waste chicken fat methyl ester can be used at low fractions as a substitute for traditional diesel fuel without modifying the engine, and this is a promising solution for waste management, turning waste products into an energy source, and dwindling fossil fuel reserves. • Biodiesel was produced with the following of esterification and transesterification methods. • Chicken fat biodiesel blends were tested in terms of exergy and exergoeconomics. • Theory of Exergetic Cost (TEC) was applied to discuss the performance comparison of the test fuels. • Chicken oil biodiesel fuels presented very competitive results in terms of performance indicators. • Exergy costs for crankshaft work for D100 and B100 were 110.02 and 197.37 $/GJ, respectively. [ABSTRACT FROM AUTHOR]

The soybean oil wastes are disposed of after being used multiple times (maximum utilization) in the various food processing industries. Disposal of such waste are harmful to the environment and human. Hence, this investigation aims to use such wastes are used for producing alternate fuels for diesel engines. The biodiesel produced from the soybean waste cooking oil by transesterification process with different hybrid catalysts such as the membrane of Poly-acrylonitrile nanofibrous (MPANF), Alkyl-celite (AC), Iron oxide (IO-II) and Ni-doped ZnO (NDZ). The transesterification process variables like flow velocities varied from 0.3 to 1.5 mL/min and the reaction time varied from 15 to 75 h. The influence of such variables was investigated. The best two yields of waste soybean oil (BDWSBO) with the use of IO-II and AC catalysts respectively at 1.5 mL/min of flow rate at a 75-h reaction time, were considered for preparing further blends with diesel of 25 vol% and 50 vol% (Total 4 fuel varieties other than plain diesel). The test results revealed that a blend of 25 % diesel fuel with 75 % IO-II -used BDWSBO has 30.05 % BTE, which is nearer to diesel fuel (30.81 %). This blend has 17.96 % lesser smoke opacity than diesel fuel. Therefore, this 25 % diesel fuel with 75 % IO-II -used BDWSBO blend is recommended for higher production biodiesel and application in the IC engine as an alternate fuel without any modifications. • Biodiesel production from for disposed soybean oil from food industries. • Discussed the catalyst role in producing the biodiesel on the engine behaviours. • Biofuel production analyzed at various flow rate and reaction time. • B50, B75 blends analyzed with respect to engine load and kinds of biodiesels. [ABSTRACT FROM AUTHOR]

The novel goal of the present research is to integrate response surface and life cycle assessment methods to reduce the environmental impacts of mechanical power generation in a diesel engine fueled by diesel-biodiesel blends. Environmental impacts of mechanical power generation in an OM 314 diesel engine under the effect of biodiesel were investigated using the life cycle assessment method. Response surface methodology was used to find the optimum percentage of alga biodiesel in diesel-biodiesel fuel blends under the effects of different engine loads and speeds. In the optimization process, the dependent variables were engine performance characteristics and emissions. A blend containing 57 % diesel and 43 % biodiesel was found as the optimum fuel blend. The environmental impacts of the optimum diesel-biodiesel blend were calculated by the CML-IA baseline impact assessment model and compared with those of pure diesel and pure biodiesel. The results showed that the values of abiotic, abiotic fossil fuel, and ozone layer depletion indicators decreased by 16.09–44.09 % compared to pure diesel. Also, the values of other indicators decreased by 16.74–131.84 % compared to pure biodiesel. Normalization process showed that the marine aquatic ecotoxicity was the main indicator for all studied fuels. • Environmental impacts of diesel power were calculated by life cycle assessment. • Different biodiesel-diesel fuel blends were tested in a diesel engine. • The optimum fuel blend was obtained by response surface methodology. • Optimum fuel with high engine characteristics and low emissions had 43 % biodiesel. • Abiotic and ozone layer depletion indicators decreased by increasing biodiesel. [ABSTRACT FROM AUTHOR]

The depletion of fossil fuels necessitates the development of sustainable and energy-efficient techniques for biodiesel production. In recent years, cavitation reactors have emerged as a viable alternative to conventional biodiesel synthesis methods due to their superior conversion rates and shorter processing times. These reactors possess a high surface-to-volume ratio and facilitate efficient heat and mass transfer. This study aims to optimize the production of biodiesel from linseed oil using a novel ultrasonic cavitation reactor through a hybrid approach. In order to achieve this, an L 50 orthogonal array with five factors and three levels was developed using a Box-Behnken design based on response surface methodology (RSM). These factors included the molar ratio (4:1, 6:1, and 8:1), ultrasonic power (100, 125, and 150 W), temperature (25, 35, and 45 °C), time (3, 6, and 9 min), and ultrasonic frequency (25, 30, and 35 kHz). The parameters were optimized using RSM-based desirability, genetic algorithm (GA), and particle swarm optimization (PSO) approaches. The results indicated that the RSM-based optimization approach outperformed the other methods. The optimal combination of parameters obtained through RSM consisted of molar ratio of 6.58:1, ultrasonic power of 133.65 W, temperature of 37.44 °C, time of 7.71 min, and pulse frequency of 26.29 kHz. This combination resulted in a biodiesel yield of 95.25%. Furthermore, this study explored the impact of different linseed oil methyl ester, octanol, and diesel blends (B10, B20, B30, B10 (O-10), and B20 (O-10)) on engine performance and emission characteristics. The B20 (O-10) blend exhibited significant potential for simultaneously reducing emissions and enhancing engine performance. When used as engine fuel, the B20 (O-10) blend increased brake thermal efficiency (BTE) by 0.848%, decreased brake specific fuel consumption (BSFC) by 0.607%, and decreased CO, HC, and NO x emissions by 18.75%, 6.55%, and 0.72%, respectively, compared to pure diesel at rated power. [Display omitted] • Intensified biodiesel synthesis using ultrasonic-assisted technology. • A Hybrid RSM-GA-PSO based approach to understand the effect of operating parameters on the biodiesel yield. • Significant process intensification benefits in terms of higher yield and reduced time. • The optimal combination of parameters led to a biodiesel yield of 95.25%. • Effect of a novel ternary blends (Linseed Biodiesel + Diesel + Octanol) on engine characteristics. [ABSTRACT FROM AUTHOR]

Vegetable oil based fuels are promising substitutes for diesel fuel for transport and industrial applications. Converting raw vegetable oils into their ethyl or methyl esters has reasonably solved the problems associated with their high viscosities. The purpose of the research is to investigate experimentally the effect of injection pressure on the combustion characteristics of a biodiesel engine using cerium oxide nanoparticles as a fuel additive. Biodiesel derived from waste cooking oil mixed with mineral diesel in the proportion 20:80 is used along with cerium oxide (CeO 2) nanoparticles as additives. The engine is run at several fuel injection pressures (180, 210 and 240 bar) and with a nanoparticle concentration of 80 ppm. The experiments demonstrate that the higher injection pressure associated with nanoparticle addition improves engine combustion characteristics, e.g., it leads to a higher peak pressure and a higher heat release rate. The best performance was observed at an injection pressure of 240 bar with a 80 ppm nanoparticle concentration. Concentrations of hydrocarbon, oxides of nitrogen and smoke decreased for higher injection pressures with nanoparticle addition. Hence an enhancement in engine performance and decrease in emissions can be achieved in a biodiesel engine by employing higher injection pressures with nanometer sized cerium oxide particles as additives. This helps in conserving the petroleum based fuels and also avoiding the emissions of contaminants to the atmosphere. • Influence of fuel injection pressure with CeO 2 on the CI engine combustion were studied. • Higher cylinder pressure and heat release rate were found for CeO 2 blended biodiesel. • Reduced energy consumption was observed with CeO 2 nanoparticle at higher injection pressures. • Reduced emissions were obtained with CeO 2 nanoparticle at higher injection pressures. [ABSTRACT FROM AUTHOR]

The objective of this work was to compare the effect of diethyl ether (DEE) and methyl tertiary-butyl ether (MTBE) addition to biodiesel and diesel blends on diesel engine. The ethers concentration have been varied in proportion of 5% and 10% on volume basis with biodiesel by keeping the diesel concentration as 50% for all ternary blends preparation. Experimental results revealed that D50-B45-DEE5 ternary blend has shown 5.3% increase in thermal efficiency compared to other ternary blends. On the other hand, D50-B45-MTBE5 and D50-B45-DEE ternary blends have reduced CO emission by 8.1% and 14.8% respectively when compared to high speed diesel fuel. Furthermore, the D50-B40-DEE10 blend and D50-B40-MTBE10 reduce the NOx emission by 32% and 8.8% when compared to HSD at maximum load condition. Significant reduction is noted in HC emission for all ether added ternary blends than that of HSD and biodiesel fuels. However, the smoke emission is decreased marginally for D50-B45-DEE5 than that of HSD fuel. Finally, it is evident that both the DEE and MTBE could be used as viable additive with diesel or biodiesel in binary and ternary forms for diesel engine applications. • 5–10% of diethyl and methyl tertiary butyl ether are used in ternary blends. • 5% of diethyl ether in ternary blend has shown higher brake thermal efficiency. • ➢8–15% of carbon monoxide emission is reduced for 5% of ethers addition. • ➢45% reduction in NOx emission is achieved by 10% diethyl ether addition. • ➢All ternary diesel-biodiesel-ether blends reduced the HC emission. [ABSTRACT FROM AUTHOR]

In this study, spray characteristics of biodiesel blending with di- n -butyl ether (DBE15, DBE30) were investigated by experiment and analysis and compared with diesel. Spray characteristics parameters including spray tip penetration, spray cone angle, maximum spray width and spray tip velocity were used to compare under different injection pressures and ambient pressures. The spray images were analyzed according to light intensity level, while the gas entrainment mass and equivalent ratio were analyzed by empirical model. The results showed that the spray tip penetration of biodiesel added with DBE was reduced and the spray cone angle and maximum spray width were increased. The range of light intensity level of biodiesel was the narrowest, while the light intensity level of biodiesel-DBE blends was similar to that of diesel. Empirical models showed that biodiesel shows poor gas-fuel mixing. DBE30 had a larger gas entrainment mass and a lower equivalence ratio, similar to diesel. It was proved that the biodiesel added with DBE enhanced the gas-fuel mixing. • The authors declare that they have no conflict of interest. • Macroscopic spray features of biodiesel blending with di- n -butyl ether was studied. • Light intensity distributions of different fuel sprays were compared. • Gas entrainment according to empirical model was analyzed for different tested fuels. [ABSTRACT FROM AUTHOR]

This study investigates the influence of biodiesels on combustion and emission characteristics in a common-rail equipped small-bore single-cylinder diesel engine. The engine experiments were performed using waste-cooking-oil (WCO), Jatropha-oil, and Karanja-oil derived biodiesels. Conventional diesel was utilized as a baseline fuel. The test engine was operated at a speed of 1200 rpm and an indicated mean effective pressure of 0.5 MPa. The fuels were injected at fuel injection pressures (FIPs) of 40, 80, and 120 MPa. At the same time, the fuel injection timing was varied from −15 crank angle degrees (CAD) after top dead center (aTDC) to −3 CAD aTDC. Experimental results showed that ignition delay was directly correlated to the cetane number and had more significant effect at higher FIPs. The peak of in-cylinder pressure increased as the injection timing was advanced, due to longer ignition delay. Biodiesels showed relatively lower or equal level of nitrogen oxides (NOx) emissions compared to conventional diesel. This was mainly due to lower combustion efficiency showing high amount of smoke, HC, and CO emissions from incomplete combustion. However, for the WCO biodiesel, smoke, HC, and CO emissions could be significantly improved than other biodiesel thanks to better atomization and air-fuel mixing process. • Jatropha and Karanja biodiesel had shorter ignition delays than diesel. • Diesel and WCO biodiesel showed higher portion of pre-mixed combustion. • Smoke, CO, and HC emissions from biodiesels were higher than diesel. • In most conditions, biodiesel fuels showed lower NO x emissions than diesel. [ABSTRACT FROM AUTHOR]

Biodiesel appears as a replenishable and sustainable energy source and can be used a direct replacement to petro-diesel without any major transformations in ongoing diesel engines. This work concentrates on production of Calophyllum Inophyllum biodiesel (CIB) and preparing 10% blend (CIB10) sample to investigate the effects of varying the injection strategies and exhaust gas recirculation (EGR) in common-rail direct injection engine. The experimental results shows that 10% of pilot fuel and 90% main injection strategy (B10@P10-M90) is superior among all others injection strategies with respect to pure diesel. B10@P10-M90 fuel injection strategy produces the maximum efficiency of 35.8% and lowest fuel consumption of 0.25 kg/kWh compared to all the injection strategies. The carbon monoxide (CO) and hydrocarbon (HC) emissions are also found to be quite low compared to all the other test samples including pure diesel. However B10@P10-M90 results in higher average oxides of nitrogen (NO x) emission which is 18.9% higher in contrast to conventional diesel at full load condition. With the implementation of 10% and 20% EGR with B10@P10-M90, the average NO x emissions decreased by 14.4% and 27.6% respectively compared to B10@P10-M90 without any EGR without significant loss in the performance of the existing diesel engine. • Calophyllum Inophyllum biodiesel is extracted and utilized in CRDi engine. • Engine parameters such as injection strategies and EGR was investigated. • Efficiency is increased and fuel consumption is reduced for the CIO blend. • Better combustion characteristics were obtained by varying the injection strategies. • Reduction in HC, CO and smoke emissions were observed for injection strategies. [ABSTRACT FROM AUTHOR]

The spray combustion characteristics of sunflower (Helianthus annuus) biodiesel/methyl esters (SFME) and 50% SFME/diesel blend and diesel were investigated via a liquid swirl flame burner. The swirl flame was established at atmospheric condition by using a combined twin-fluid atomiser-swirler configuration at varied atomising air-to-liquid ratios (ALR) of 2.0–2.5. Diesel flame showed a sooty flame brush downstream of the main reaction zone, as opposed to the biodiesel flame which showed a non-sooty, bluish flame core. Biodiesel flame exhibited a more intense flame spectra with higher OH* radicals as compared to diesel. Higher preheating main swirl air temperature led to higher NO emission, while CO correspondingly decreased. Sunflower-derived biodiesel generally exhibited slightly higher NO and CO levels than diesel when compared at the same power output, mostly due to higher flame temperature and fuel chemistry effect. By increasing ALR, a significant reduction of NO and CO for both fuel types were concurrently achieved, presenting a strategy to control emissions and atomise biodiesel with higher viscosity under swirl combustion mode. • Sunflower biodiesel swirl flame exhibits a bluish flame with no visible sooty flame brush. • Higher OH* radical intensity is shown in sunflower biodiesel flame spectra. • Main swirling air temperature has an impact on the emissions of CO and NO. • Sunflower flame shows slightly higher NO and lower CO at inlet temperature of 250 °C. • Varying of the injector's atomising air-to-liquid ratio is effective in reducing emissions. [ABSTRACT FROM AUTHOR]

Limited fossil fuel reserves led to focus on alternatives fuels for combustion engines. Several studies reported optimal (20%) biodiesel blend for utility in compression ignition engine at constant compression ratio. Literature lacks on the study of palm-based biodiesel in blended form at varying engine compression ratios. In this study, an initiative was undertaken to study the effect of variable compression ratio (16:1, 17:1 and 18:1) on various engine characteristics by fuelling 20% palm biodiesel blending compression ignition engine. The ignition delay period decreased, whereas the peak cylinder pressure and brake thermal efficiency increased with increase in the engine compression ratio from 16:1 to 18:1. At 3.5 bar bmep, brake thermal efficiency values were observed to be 28.9, 30.8 and 33.8% at 16:1, 17:1 and 18:1 CRs, respectively in B20 fuel. Moreover, increasing compression ratio from 16:1 to 18:1, the average reduction in emissions of hydrocarbon, carbon monoxide and smoke opacity were observed to be 47.8, 41.0 and 35.7%, respectively whereas, oxides of nitrogen emissions increased by 41.1%. Thus, it is inferred that B20 fuel performed well at high engine compression ratio. • B20 fuel utilized in CI engine by varying bmep and compression ratio. • Shorter ignition delay with B20 when compared to diesel. • PCP increases with increasing CR led to improve BTE. • Reduction in CO, HC and smoke emissions with increasing CR. • NO x emission increases with increasing compression ratio. [ABSTRACT FROM AUTHOR]

With deteriorating energy reserves, rising environmental apprehensions and progressively more firm energy regulations have made renewable energy resources as an extremely attractive alternative source for near future. Biodiesel was considered as one of the promising energy resource for diesel engines. In the present work, non-edible oils namely pumpkin seed oil and Moringa oleifera oil were converted into methyl ester of Pumpkin seed oil (B1) and Moringa oleifera oil (B2) using transesterification process. The engine modification technique was said to be one of the current development in the field of the engine research motivating to achieve complete combustion. Two novel bowl geometries namely Toroidal Combustion Chamber (TCC) and Trapezoidal Combustion Chamber (TRCC) were developed and compared with standard Hemispherical Combustion Chamber (HCC). Further, the work was progressed to exergy and energy analysis. Amongst the bowl geometries, TCC showed better engine characteristics than TRCC and HCC. High swirl and squish behaviour of TCC engine helps in better air-fuel mixing and leads to complete combustion. Biodiesel samples contain oxygen molecules in its structure, reduced engine exhaust emissions except NOx were observed. On the whole, B1 may be considered as the promising alternative fuel as it exhibited 66.51% of exergy efficiency in TCC engine. Image 10939 • Raw Pumpkin seed oil and Moringa oleifera oil were converted into respective biodiesels using transesterification. • Two bowl geometries namely Toroidal Combustion Chamber (TCC) and Trapezoidal Combustion Chamber (TRCC) were developed. • Energy and exergy analysis revealed that the TCC engine exhibited better engine characteristics than HCC and TRCC. • Diesel and B1 sample showed higher thermal efficiency and lower fuel consumption than B2. • In TCC engine, B1 biodiesel showed lower emission characteristics (except NOx) than other samples. [ABSTRACT FROM AUTHOR]

The present experimental work focuses on the combined effect of nano additives, combustion chamber geometry and injection timing in a single cylinder diesel engine fuelled with ternary fuel (diesel-biodiesel-ethanol) blends. Ternary fuel (TF) is doped with alumina nano additives and the resulting fuel is termed as high performance fuel (HPF). HPF is subjected to different combustion chamber geometries and TRCC (torroidal re-entrant combustion chamber) geometry is found to be effective among other geometries. HPF operated at TRCC chamber is subjected to four different injection timings namely, 21obTDC (HPF-TRCC21), 22obTDC (HPF-TRCC22), 23obTDC (HPF-TRCC23) and 24obTDC (HPF-TRCC24) respectively. BTE is lowered for HPF-TRCC21 and HPF-TRCC24 by 4.53% and 1.22% while highest BTE of about 33.8% is achieved for 22obTDC in comparison with other blends such as DIESEL-HCC23 (32.75%), HPF-TRCC21 (31.41%) and HPF-TRCC24 (32.53%). Lowest BSEC profile was achieved for HPF-TRCC22. HPF-TRCC22 resulted in lowered HC and CO emissions of about 9.18% and 16.83% in comparison with HPF-TRCC23. HPF-TRCC21 resulted in lowered NOx emissions by 22.53% along with higher HC and CO emissions by 6.13% and 20.51% in comparison with HPF-TRCC23. Cylinder pressure and HRR of HPF-TRCC22 stays at an acceptable range of 75.42 bar and 85.34 J/deg CA in comparison with other test blends. The DIESEL-RK theoretical simulation results are compared with the experimental study conducted at the same operating conditions and its revealed that TRCC combustion chamber geometry is better for enhanced performance and combustion characteristics. • Novel study on combined effect of nano additives, geometry and injection timing. • In-cylinder flow simulation of different combustion chambers with DIESEL-RK software. • Ternary fuel with 20 ppm alumina nano additive was called high performance fuel. • 22oTDC with torroidal re-entrant chamber ensued highest BTE and lowest BSEC. • At 22obTDC, HC and CO were lowered along with marginal higher NOx emissions. [ABSTRACT FROM AUTHOR]

For the current research work, New Zealand origin sheep skin fat (NOSSF) with 7% free fatty acid (FFA) content was chosen for biodiesel production. The response surface methodology (RSM) was used to optimize the acid catalyzed esterification of NOSSF. Analysis of variance (ANOVA) showed methanol to NOSSF mole ratio as an important parameter for the acid esterification reaction. The p-value < 0.05 and F-value = 401.18 showed that quadratic model is significant. NOSSB yield of about 92% was achieved, when the acid esterification was carried out with 0.5 wt% H 2 SO 4 , 18:1 methanol: NOSSF mole ratio at 65 °C for 4 h followed by alkali-catalyzed transesterification of NOSSE with 0.5 wt% NaOH, 6:1 methanol: NOSSE mole ratio at 65 °C for 2 h. The physicochemical properties of NOSSB-PBD blends were evaluated and were observed to be well within the limits of ASTM D765 standards. Among all the blends, the NOSSB20 blend, showed good performance in par with PBD fuel operation with respect to BTE, BP and BSFC at full load. NOSSB-PBD blends emitted less CO and HC but more CO 2 and NO x emissions than PBD. Image 10474 • Biodiesel was produced from high free fatty acid fats derived from leather wastes. • Analysis of variance showed methanol to fat mole ratio as a significant variable. • Test fuel property was within limits of prescribed standards. • Brake thermal efficiency and brake power of test fuel were lower. • Test fuel emitted less CO and HC emissions, but higher NO x and CO 2. [ABSTRACT FROM AUTHOR]

Abstract The objective of this work is to study the addition of n -pentanol with the Calophyllum Inophyllum biodiesel to evaluate the performance, emission and combustion characteristics. Five different fuel blends are prepared by varying the n -pentanol fraction (10%, 20%, 30%, 40% and 50%) on volume basis with biodiesel. The prepared samples are tested in single cylinder constant speed CI engine. The addition of n -pentanol with biodiesel improves the thermal efficiency of the fuel blend up to 30% as compared to pure biodiesel. Among all fuel samples, B90P10 blend has shown higher brake thermal efficiency as 27% which is slightly lower than BTE of diesel fuel. The brake specific fuel consumption of biodiesel-pentanol blends are increased from 4.2% to 27.3% when compared to diesel fuel (D100). However, addition of n -pentanol more than 40% shows a negative effect in terms of performance and combustion. It is noted that biodiesel and n -pentanol blends have shown 15–43% and 33–50% reduction in hydrocarbon and carbon monoxide emissions compared to diesel. Further, the oxides of nitrogen and smoke emissions are found to be lesser for n -pentanol blends while comparing to the pure biodiesel. Among all blends, B90P10 is found to have better performance and emission characteristics. Highlights • n -pentanol is add with Calophyllum Inophyllum biodiesel at fractions of 10%–50%. • Engine characteristics of higher alcohol blend with biodiesel is studied. • Performance of n -pentanol fraction for 10%, 20%, 30% is superior than pure biodiesel. • NOx emissions is reduced for the n -pentanol fractions with biodiesel. • Ignition delay is increased for the n -pentanol blends due to low cetane number. [ABSTRACT FROM AUTHOR]

Abstract In this research work, the four ternary blends were prepared with 30% and 40% by volume of higher alcohol (decanol and hexanol) with biodiesel while maintain 50% of diesel concentration. All ternary blends of diesel-biodiesel-higher alcohols were used in single cylinder engine and the results were compared with binary blend of 50%–50% biodiesel, pure diesel and biodiesel. It was revealed that thermal efficiency of ternary blends was higher than biodiesel and in some cases it is closer to pure diesel. In contrary, specific fuel consumption is found to lower with increase in alcohol fractions in ternary blends. Moreover, hydrocarbon, smoke, carbon monoxide emissions from alcohol-infused fuel blends were observed to be lower than both biodiesel and pure diesel. Significant reduction in oxides of nitrogen (NOx) emissions was also observed by the addition of higher alcohols to the fuel blend when compared to biodiesel fuel. It is to be noted that decanol 40% addition with diesel and biodiesel blend has shown better results in emission characteristics. Furthermore, the heat release rate and in-cylinder pressure for biodiesel were significantly lower compared to pure diesel fuels. However, addition of 40% decanol with fuel blend improved the heat release rate and in-cylinder pressure. Highlights • Hexanol and Decanol are used as additives for ternary blends preparation. • Alcohol concentration has been varied in the proportion of 30% and 40% on volume basis. • Decanol shows improved efficiency with less fuel consumption for higher fractions. • Addition of higher alcohol reduces the HC, CO, NOx and smoke emissions. [ABSTRACT FROM AUTHOR]

Abstract The focus of this investigation is on biodiesel produced from juliflora seeds using the 2-stage acid transesterification process followed by alkali transesterification process producing 80% yield of Juliflra Oil Methyl Ester. Experiments were conducted on single cylinder diesel engine using juliflora biodiesel and its diesel blends. The experimental results of fuel blends (B20, B30, B40, and B100) were compared with those from diesel (D100). The results indicated the performance and combustion characteristics of B20 as almost in line with those of diesel fuel trend. Brake Specific Fuel Consumption (BSFC) for blends B20 and B30 (0.27kg/KWh) at full load was closer to diesel (0.26 kg/KWh). The BTE for Juliflora Biodiesel B100 is 31.11% and it was closer to diesel (32.05%) at full load. However the emission characteristics of CO, HC and smoke for biodiesel and its blends were smaller or equal compared to diesel throughout the experiment. At full load, the NOx for biodiesel B100 was 1832 ppm which was a little higher than diesel fuel (1821 ppm). This led to the conclusion of B20 being most suitable blend of other blends and it is substitute of diesel which will reduce diesel consumption by 20%. Highlights • Juliflora biodiesel used as fuel in diesel engine. • BSFC of blend B20 is much closer to diesel. • HC, CO emission and Smoke opacity of B20 is much lower than diesel. • NOx emission of B20 is slightly higher than diesel. [ABSTRACT FROM AUTHOR]

Abstract This work is a study of tribo-corrosion and engine characteristics of Aegle Marmelos Correa biodiesel and its diesel blends. The tribology results revealed that B50 showed the lowest steady-state coefficient of friction (SSCOF) amongst all the other blends. SSCOF of B100 is 23.27% more than B50. Similarly, SSCOF of B90, B60, B20, B10, and diesel are 19%, 8%, 17.23%, 31.9% and 40.11% greater than the SSCOF of B50 respectively. Wear scar diameter (WSD) results also showed that B50, B60, B90, and B100 have lower WSD of around 0.6 mm. Diesel showed the highest WSD of 0.8 mm. Flash temperature parameter (FTP) is inversely related to WSD, and thus B50, B60, B90, and B100 exhibited higher FTP of around 80. On evaluating the corrosion characteristics, B50 exhibited lesser corrosion inducing capability compared to all the other blends. Experimental investigation of the engine showed that B100 yielded lesser thermal efficiency and higher specific fuel consumption than diesel. The CO, HC, NO, and smoke emissions were minimum for B100 when compared to diesel. Finally, all the results revealed that B100 is the ideal blend that can perform efficiently and be a sustainable energy source for diesel engines. Highlights • B50 exhibited the lowest SSCOF compared to other blends. • Wear scar diameter of B50, B60, B90 and B100 is observed similar. • Diesel has the highest WSD and lowest FTP compared to other blends. • Diesel is found to produce less corrosion on metals. • Minimum CO, HC, NO and smoke emissions were obtained for B100. [ABSTRACT FROM AUTHOR]

Abstract In this study, a diesel engine was modified to operate in dual fuel mode with natural gas as the main fuel and a novel fuel mixture of biodiesel and glycerol triacetate additive as pilot fuel. Regarding to experimental tests results, engine emissions were modeled using a combination of artificial neural network and genetic algorithm to determine the appropriate ratio of pilot fuel to gaseous fuel, biodiesel and additive to reduce engine emissions. The algorithm inputs were engine torque, pilot fuel and natural gas consumption, biodiesel and additive proportions in pilot fuel, while outputs were exhaust emissions including NO x , PM, CO, and UHC. Overall, the results of the modeling were consistent well with experimental data. Simulations were performed for a variety of biodiesel and additive compositions and it was accordingly concluded that by using biodiesel and additive, NO x and CO emissions were reduced by up to 63% and 42%, respectively, while PM was reduced substantially by 27 times in comparison with neat diesel fuel in the diesel operation mode. In the dual fuel mode, 24% reduction in NOx emission. However, under these circumstances, UHC emission was 10% higher than that of the diesel operation mode. Highlights • Biodiesel and GTA additive use as pilot fuel in dual fueled engine. • GTA additive and biodiesel influence on engine emissions reduction. • Dual fueled diesel engine emissions discussed experimentally and theoretically. • Engine emissions modeled by Artificial Neural Network and Genetic Algorithm. • Engine emissions map obtained from modeling. [ABSTRACT FROM AUTHOR]

Abstract This paper presents the overall performance, emission and combustion characteristics of the engine, when fuelled with biodiesel blends of Calophyllum Inophyllum methyl ester as injected fuel and babul wood chip derived producer gas as inducted fuel at constant injection timing (230bTDC), injection pressure (230 bar) and speed (1500 rpm). To improve overall performance, combustion and reduced emission characteristics of the engine, the combustion chamber was varied with 5 different geometries. Experimental results revealed that Toroidal re-entrant combustion chamber had higher Exhaust Gas Temperature and Brake Thermal Efficiency by 20.75% and 6.37% than that of HCC, while Brake Specific Fuel Consumption was reduced by 4.49% at optimal loading condition. However, engine overall performance of TrCC was found to be comparable with Hemi-spherical chamber and other designed combustion chambers. Similarly, comparing exhaust emissions, Oxide of Nitrogen and Carbon dioxide were on its higher side by 19.90% and 27.20% than normal HCC. On the contrary, carbon monoxide, Hydrocarbon and Smoke opacity for TrCC were found to be 76.12%, 33.71% and 38.67% lower than HCC. From the above study, it is finally concluded that converted renewable fuels with TrCC might be utilized as an alternative fuel without any exhaust related problems. Highlights • CIME 20 showed better oil characteristics. • BTE for CIME 20-producer gas with TrCC was 6.37% higher than diesel HCC. • NO x emission for HCC-diesel was 19.9% lower than TrCC CIME20 P. gas. • CIME 20-producer gas with TrCC emits 33.71% and 38.67% less HC and smoke. • Diesel fuel savings of 80.5% for diesel-producer gas at optimal load condition. [ABSTRACT FROM AUTHOR]

Abstract The present work encompasses combustion, performance, and emission parameters of experimental investigations of a single cylinder, four stroke, water cooled, direct injection (DI), naturally aspirated compression ignition (CI) engine with a rated power output of 3.7 kW at constant engine speed (1500 rpm) using diesel and different blends of microalgae spirulina. The microalgae spirulina blend of ratio with diesel (BYY) where YY indicates blending percentage (0%, 20%, 40%, 60%, 80%, and 100% volume basis with diesel respectively) with different engine loading condition (25%, 50%, 75% and 100%) were compared with diesel at CR17.5:1. The output illustrates that the most optimum value is B20% when compared with diesel. The result depicts firstly that there is a reduction in brake thermal efficiency by 0.98%, exhaust gas temperature by 1.7%, hydrocarbon (HC) by 16.3%, carbon monoxide (CO) by 3.6%, NO X emission by of 6.8%, and smoke emission by 12.35% respectively. Secondly, there is an increase in specific fuel consumption by up to 5.2% and CO 2 emission by 2.8% for spirulina blend ratio (B20%) as compared to diesel (B0%) at full load condition engine with constant engine speed. Highlights • Diesel-biodiesel blends obtained better performance of B20 as compared to diesel. • Microalgae spirulina biodiesel combustion performance is comparable with diesel. • Blends were found as an effective way to reduce the NO X and PM emissions. • Shows the enormous potential to reduce of CO 2 emission with increase engine load. [ABSTRACT FROM AUTHOR]

Abstract This paper describes the application of Fuzzy Logic, Genetic Algorithm (GA) and Fuzzy Analytic Hierarchical Process-Technique for Order Preference by Similarity to Ideal Solution (FAHP-TOPSIS) for the selection of optimum blend from the various alternative blends of fish oil and diesel. A single cylinder, constant speed and direct injection diesel engine with a rated output of 4.4 kW is used for exploratory analysis at different load conditions. Ten parameterssuch as maximization of brake thermal efficiency, rate of pressure rise and minimization of NO x, CO 2 , CO, HC, smoke, exhaust gas temperature, ignition delay and combustion delay are considered. From the experimental data, multi input multi output (MIMO) fuzzy models are developed using triangular membership functionto predict the engine parameters. The developed model has good correlation with the observed data with noticeably low errors. Then, for each parameter, optimum blend has to be identified for all the loads using genetic algorithm which is a multi-objective optimization process. The engine performance is accurately predicted for the identified best load and blend from the developed fuzzy model. Hence in the proposed model, fuzzy logic is integrated with GAto find the best blend. Finally, from the best blend of each parameter, the exact biodiesel proportion of about 17% for no load, 17% for 25% load, 18% for 50% load, 17% for 75% load and 20% for 100% load are found out usingTOPSIS which will best suit the engine performance and reduction of emissions. Highlights • Analyzed the combustion characteristics of fish oil biodiesel. • Fuzzy-GA to predict the performance. • TOPSIS to evaluate the best blend. [ABSTRACT FROM AUTHOR]

This paper presents an inquiry into the internal flow and spray behavior of diesel and biodiesel in a triangular orifice, using experimental and numerical methods. The inner flow was analyzed through the implementation of Large Eddy Simulation model. Furthermore, two high-speed cameras were utilized to capture spray images of the major and minor axes of the triangle-shaped nozzle simultaneously. The investigation revealed that, in comparison to diesel, biodiesel exhibited a higher discharge coefficient. Additionally, the vorticity magnitudes and turbulence vortex structures for biodiesel were consistently lower than those for diesel. The use of biodiesel can hinder the occurrence of cavitation. Moreover, it was observed that the triangular spray cone angle displayed axis-switching phenomena for both fuels. The axis-switching phenomenon is suppressed by using biodiesel. The research also discovered that the triangular biodiesel spray has a longer spray tip penetration and a smaller angle in all view planes. This could be attributed to the higher viscosity and surface tension of biodiesel, as well as the inhibition of the spray axis-switching during the injection, leading to an increase in the spray tip penetration and a decrease in the spray cone angle for biodiesel. • Higher discharge coefficient for biodiesel in triangular orifice. • Biodiesel utilization mitigates cavitation initiation. • Biodiesel curbed the occurrence of spray axis-switching phenomenon. • Biodiesel showed prolonged spray penetration and reduced angle in all planes. [ABSTRACT FROM AUTHOR]

Ammonia is an alternative carbon-free fuel that can be easily stored in a liquid phase, unlike hydrogen, and then directly utilized in diesel engines. Hence, a single-cylinder diesel engine was retrofitted for direct injection of liquid ammonia with pilot ignition of biodiesel in dual fuel combustion mode. The effects of the liquid phase of ammonia and ammonia energy share (AES) on combustion, emissions, and engine performance were investigated and compared with pure biodiesel operation. Moreover, various ammonia injection timings were studied to improve ammonia/biodiesel combustion and reduce emissions. A CFD model was developed and validated with experimental data to study ammonia/biodiesel sprays, combustion characteristics, and emissions formation. The results showed higher AES significantly reduced the local cylinder temperature due to the strong cooling effects of ammonia, therefore, a maximum AES of 50% was achieved. Increasing AES to 50% decreased combustion duration and combustion phasing by 26.2 and 4.4 CAD, respectively. However, it deteriorated the indicated thermal efficiency (ITE) by 1.3 percent point compared to pure biodiesel. Furthermore, retarding ammonia injection from −25 to −10 CAD significantly reduced NO x , CO, and ammonia emissions by 31.4%, 39.6%, and 31.3%, respectively. Ultimately, the optimal operating condition was suggested when ammonia was injected at −10 CAD and biodiesel at −16 CAD with AES of 50%. • The ammonia-biodiesel dual direct injection engine was investigated. • The ammonia spray and combustion characteristics were studied by the CFD. • Direct ammonia injection reduced unburned ammonia by 10813 ppm compared to the port injection. • Late injection of ammonia at −10 CAD reduced NO x and NH 3 emissions by 31% at the same time. [ABSTRACT FROM AUTHOR]

Problems such as air pollution caused by engine burning fossil fuels are becoming increasingly severe. Consequently, the pursuit of clean and efficient energy alternatives, as well as enhancements in the combustion of fossil fuels, have emerged as potential avenues for resolving these challenges. Firstly, a 3D simulation model of the engine is made using the CONVERGE program. Then, the biodiesel-hydrogen (0%, 5%, 10%, and 15%) blends are employed to investigate the combustion processes for the diesel-fuel engine at various loading (50%, 75%, and 100%). Finally, the response surface approach is employed to optimize the biodiesel-hydrogen engines' combustion and emission parameters. The findings demonstrate that combustion pressure and temperature in engine cylinders will also rise as the hydrogen level increases. The hydrogen addition to the engine can enhance its combustion and emission properties. The outcomes prove that 0.656 is the ideal value for multi-objective optimization analysis using the response surface method. The engine reaches optimal working conditions when the hydrogen energy percentage is 6.9%, the load is 100%, and EGR is 7.7%. At this moment, the BSFC, BTE, HC, and NO x emissions were 208.31 g/(kW·h), 41.06%, 340 ppm, and 490 ppm, respectively. • Effects of hydrogen addition on combustion and emission characteristics are investigated in a highland. • The optimization method integrated with the RSM has been developed. • The RME is employed to investigate the multi-objective optimization. • The hydrogen addition fuel plays a very important role. [ABSTRACT FROM AUTHOR]

This study mathematically inspects the effects of engine speed/load and biodiesel–hydrogen fuel blend composition on CO 2 , CO, and NO x emissions. Since this modeling task requires a basic knowledge of mechanics, chemistry, and combustion, the literature suggests no approach to anticipate these emissions. This multi-input and multi-output (MIMO) problem is so complex that can only be simulated by special types of machine-learning tools. Consequently, this study utilizes the multi-output least-squares support vector regression (MLS-SVR) and two efficient artificial neural networks (cascade feedforward and multilayer perceptron) to handle this complicated MIMO regression. These intelligent models are constructed and tested using 307 × 3 experimental emissions related to the combustion of different biodiesel–hydrogen blends at various engine speeds and loads. Extensive numerical analyses and ranking tests are conducted to confirm that MLS-SVR is the best approach to simultaneously predict the actual CO 2 , CO, and NO x emissions with the mean absolute relative error of 2.75%, 7.00%, and 2.62%, and regression coefficient of 0.9966, 0.9947, and 0.9979, respectively. The applicability domain inspection approves that only seven emission measurements may be problematic samples and all other 300 samples are reliable. • CO 2 , CO, NO x emissions of biodiesel-H 2 combustion are simulated as a MIMO problem. • The MLS-SVR shows better performance than the MLPNN and CFFNN on this ground. • The applicability domain test approved that 300 out of 307 experiments are reliable. • Engine speed has a complex effect on CO 2 emission, reduces NO x , and increases CO. • There is an intermediate value for the engine speed that maximizes the CO 2 emission. [ABSTRACT FROM AUTHOR]

As the global population and economy grow, so does the energy demand. Over-reliance on non-renewable resources leads to depletion and price spikes, making renewable alternatives necessary. Biodiesel is an eco-friendly and non-toxic fuel that closely resembles traditional fossil fuels. It is produced from various sources, including animal fat, palm oil, and non-edible plant oil. Biodiesel releases fewer harmful air pollutants and greenhouse gases than fossil fuels and is simpler to manage. Despite these advantages, it cannot replace traditional diesel fuel on a large scale. This overview summarizes biodiesel production, explaining the different types of feedstock utilized and their benefits and drawbacks. Various biodiesel production methodologies are discussed. The primary objective of this article is to inform engineers, industrialists, and researchers involved in waste biodiesel, as well as to highlight waste biodiesel as a potential substitute for fossil fuels. This review article discusses the nano - additives in biodiesel and applications of internet of things, artificial intelligence, and machine learning in biofuel. This review shows that nano-additives can potentially improve biodiesel fuel properties, favorable economic and policy environments promoting biodiesel production, and internet of things, artificial intelligence, and machine learning technologies optimize the biodiesel production processes. These advances can help promote biodiesel as a cleaner, renewable energy source, lowering the consumption of fossil fuels. It also suggests further biofuel development by improving efficiency, expanding feedstock options, creating policy support, developing infrastructure, and increasing public awareness. • Biofuel methods, economic effects and sustainability with nano-additives discussed • Nano-additives transformed biodiesel with efficiency breakthroughs • Economic strategies and policy regulations driven sustainable biofuel transition • IoT, AI, and ML revolutionized biodiesel production and monitoring • Advancements in nano-additives and AI/ML technologies for biofuel sustainability [ABSTRACT FROM AUTHOR]

The objectives of this study were to explore the evolution process of the chemical reaction pathways in the combustion of a biodiesel surrogate fuel and to reduce the calculation burden in the numerical simulation of this combustion process due to the complicated mechanism. A mixture of methyl decanoate, methyl 9-decanoate, and n-heptane was selected as the Jatropha biodiesel surrogate fuel. A simplified combustion mechanism of the biodiesel comprising 170 components and 737 reaction components was formed by systematically simplifying 3299 components and 10806 reaction mechanisms using a multistep directed relation graph method, path flux analysis, and sensitivity analysis. The simplified mechanism was compared with the detailed mechanism and experimental data to effectively verify the accuracy of the mechanism. The simplified mechanism could reproduce the detailed mechanism, and the results were in good agreement with the experimental data in terms of the ignition time of a methyl decanoate/air mixture in a shock tube, the concentrations of the components generated in the combustion process of the biodiesel in a jet stirred reactor, and the flame propagation speed of methyl decanoate and n-heptane/air mixture. The rate of production analysis method was used to explore the main reaction pathways and the evolution process of important intermediate components in the Jatropha biodiesel surrogate fuel generated at high and low temperatures. Methyl decanoate and methyl 9-decanoate formed hydrogen peroxide ketone and oxy groups mainly through dehydrogenation, oxygenation, and isomerization at low temperatures. The high-temperature stage mainly involved bond-breaking decomposition reactions, partial dehydrogenation, and isomerization reactions of low-temperature reaction products, resulting in the formation of small molecular products. [Display omitted] • Construction of combustion simplified mechanism of Jatropha biodiesel surrogate fuel. • The simplified mechanism was verified against detailed mechanism and experimental data. • Analyze high- and low temperature reaction pathways of Jatropha biodiesel surrogate fuel. [ABSTRACT FROM AUTHOR]

Today, the transport sector, involving aviation, is the main source of greenhouse gases (GHG). At the state level, countries are trying to abandon the utilization of traditional fuels in favor of alternative ones, including electricity, biofuels, hydrogen fuel, as well as liquefied natural gas. Nevertheless, for the aviation sector, the introduction of many of these alternative fuels is difficult. The most optimal in terms of technical, technological and economic indicators is the use of biofuels produced from by-products of the agricultural and food sectors. The current article displays an overview of existing and promising new technologies for the generation of sustainable aviation fuel (SAF) from a wide variety of raw materials, including oil and fat raw materials, vegetable raw materials, food production waste, and so on. The authors suggested technologies for the generation of sustainable aviation fuel from oil and fat and vegetable raw materials. In the process of refining oil and fat raw materials by transesterification, hydrodeoxygenation, isodeparaffinization and glycerolysis, a whole list of high-quality low-carbon products is formed, such as biokerosene according to the first technology. Biokerosene is a complex bioadditive for diesel fuels and some other bioproducts. As an alternative, a technology for processing lignocellulosic raw materials based on the processes of fast pyrolysis, delayed coking, and hydrocracking has been proposed. The biokerosene obtained using this technology will not meet the existing specifications and will need a certification procedure. • Low carbon energy technologies envisaged for producing high-octane gasoline fuel were investigated. • The antidetonation performance can be varied consecutively as bioethanol > di-isobutylen > dimate > hydrocracked gasoline. • Various gasoline fuels and experimental facilities that correspond European standard regulations were employed. [ABSTRACT FROM AUTHOR]

Abstract In this study, engine performance, exhaust emissions and combustion behaviors of a single-cylinder, four-stroke, direct-injection diesel engine running on biodiesel/diesel/1-butanol and biodiesel/diesel/n-pentanol fuel blends were investigated and compared with diesel fuel under different engine speeds and full load operating conditions. Test fuels were prepared with 5 and 10 vol% 1-butanol and n-pentanol. Engine test results indicated that brake powers and torques decreased as the amount of alcohol increased, while BSFC increased between 0.77% and 8.07%. Alcohol blended fuels acquired lower EGT and CO 2 , while observing higher O 2 emission due to high oxygen content of alcohol compared to diesel fuel. Alcohol treated blends also diminished NO X by 0.56–2.65%, CO by 6.90–32.40%, and smoke by 10.47–44.43%. Moreover, n-pentanol blended fuels showed better performance and emission results than 1-butanol blends. Maximum in-cylinder pressure of higher alcohol blended fuels found between 94.55 and 95.82 bar at 371-372oCA for 1400 rpm, and between 78.19 and 82.19 bar at 375-376oCA for 2600 rpm. Alcohol addition into the blends increased maximum in-cylinder pressure up to 1.38% at low speed, whereas it decreased up to 3.75% at high speed. Furthermore, higher HRR values up to 8.5% were observed with the alcohol mixed fuels. Consequently, higher alcohols (n-pentanol and 1-butanol) can be utilized as alternative additives in biodiesel/diesel blends for diesel engines to improve emissions, although they adversely influence engine performance. Highlights • Ternary blends of biodiesel/diesel/1-butanol or n-pentanol were performed. • Cold flow properties of biodiesel/diesel blends were improved by adding alcohols. • Butanol blends lead to lower engine torque and power values than pentanol blends. • Pentanol blends have less adverse impact on BSFC and BTE than butanol blends. • Pentanol blends are better than butanol blends in reduction of NO X and CO emissions. [ABSTRACT FROM AUTHOR]

Abstract In this work, the effect of single and split injection strategy on combustion, performance and emissions characteristics of biodiesel was experimentally investigated on a common rail direct injection assisted diesel engine. In single injection strategy, Nozzle opening pressure and fuel injection timing was varied from 200 to 600 bar and 19°–27° CA bTDC respectively. Experimental results revealed that B100 had the maximum brake thermal efficiency of 35.74% at 500 bar and 25° CA bTDC. Engine exhaust emissions of unburned hydrocarbon and smoke were decreased, whereas nitric oxide emission increased in B100 fuel at higher nozzle opening pressure and advanced fuel injection timing. In split injection strategy, start of main injection timing and post injection timing was varied from 19° to 25° CA bTDC and −5° CA bTDC to 5° CA aTDC respectively. The results exhibited that the B100-90%-10% has the maximum brake thermal efficiency of 34.43%. Minimum unburned hydrocarbon and smoke emissions were obtained in B100-75%-25%. Maximum nitric oxide emission was obtained in B100-90%-10%. Thus, the experimental studies clearly states that advanced injection strategy reduces the exhaust emissions and improves the engine performance. Highlights • CH 3 ONa/Al-O-(OH) heterogeneous catalyst is used in biodiesel production. • B100 has lowest emissions at higher pressure and advanced fuel injection timing. • B100-75%-25% has lowest emissions at advanced main and post injection timing. • B100-90%-10% has maximum efficiency at advanced main and post injection timing. • Advanced injection strategy is recommended for high viscous fuel to obtain lower emissions. [ABSTRACT FROM AUTHOR]

Abstract This contribution reports experimental and theoretical studies on the transesterification of soybean oil with methanol catalyzed by zinc stearate. This reaction produces fatty acid methyl esters (FAME) and glycerol, and di- and monoglycerides as intermediate products. Response Surface Methodology was used to study the relationship between process variables and triglyceride conversion, FAME yield and initial rate. An increase in the catalyst concentration and in the methanol/oil molar ratio increased triglyceride conversion and FAME yield and decreased the initial turnover frequency values. The latter was associated with the formation of an emulsion in the reaction medium. A kinetic study of the reaction was performed. Two models were proposed. Model 1 assumed a complete mixing of the dissolved catalyst with the reactants and a second-order mechanism for the forward and reverse reactions, where the reaction system could be described as pseudo-homogeneous and the catalyst was dissolved in the reaction medium. Model 2 supposed that the dissolved catalyst formed part of a macro emulsion, with mass transfer resistance in the boundary layer around the droplets. The kinetic constants were determined, and Model 2 showed a better fit to the experimental data. The model and the kinetic parameters allow to generate reaction operation strategies. Highlights • Transesterification of soybean oil with methanol using Zn stearate as catalyst. • Response Surface Methodology was used to study reaction variables. • The reaction occurs in a macro emulsion due to the surfactant nature of the catalyst. • Two reactor models were proposed and the kinetic parameters were determined. [ABSTRACT FROM AUTHOR]

Abstract This article reports the preparation of cost-effective bio-hydroxyapatite (ram bone derived) supported mesoporous Cr heterogeneous catalysts and its performance in biodiesel production from used frying mustard oil (UFMO). The optimal catalyst (98.45 m2/g BET area; pore volume 0.0586 cc/g; modal pore diameter 19.3 nm and 0.78 mmol NH 3 /g catalyst acid-site concentration) demonstrated remarkable efficacy in sustainable synthesis of biodiesel from UFMO achieving maximum FAME content (96.85%) at optimal (predicted through D-optimal method) conditions: 4 wt% catalyst concentration, 8.0 methanol/UFMO molar ratio and 200 °C calcination temperature for catalyst preparation. Biodiesel production through concurrent transesterification-esterification (CTE) of UFMO could be augmented from 40.22% (conductive heating system) to 96.85% FAME yield using energy-proficient infrared radiation. Promising engine operation was recorded in terms of lower exhaust temperature at various blends of petrodiesel-product biodiesel in comparison with unaided petro-diesel. Assessment of exhaust emissions implied a significantly low CO (0.05%) and hydrocarbon (HC) emissions (<0.00002) for product biodiesel conforming to Euro-VI emission standards. Thus, the article demonstrates an inexpensive and efficient avenue for utilisation of waste resources to generate and utilise clean and renewable energy. Highlights • Ram bone derived bio-hydroxyapatite (BiHAp) supported Cr cost-effective catalyst. • Augmentation of concurrent transesterification-esterification by infrared radiation. • Optimization of biodiesel production using D-optimal design. • Promising engine operation and emission assessments of biodiesel-diesel blends. [ABSTRACT FROM AUTHOR]

Abstract This work aims at presenting the current works concerning the polygeneration systems simulation, by specially focusing on the potential integration of different technologies into a single system. Polygeneration allows one to produce energy vectors (power, heating and cooling) as wells as other useful products (hydrogen, syngas, biodiesel, fertilizers, drinking water etc.) by converting one or multiple energy sources. Polygeneration system can be fuelled by renewable sources (geothermal, solar, biomass, wind, hydro), as well as fossil fuels (natural gas, coal, hydrogen, etc.). In this paper innovative energy technologies, such as fuel cells and conventional ones are taken into account, by also focusing on the control strategies implemented for the proper management of polygeneration systems in general. Works regarding energy, economic and exergy analyses and system optimizations are also illustrated. Highlights • Current literature studies on polygeneration systems simulation. • The review includes conversion technologies fuelled by fossil and/or renewable energy. • A classification of methodology, outputs, control and optimization. • Contribution of polygeneration to the development of distribute generation systems. [ABSTRACT FROM AUTHOR]

Abstract Air pollutants derived from diesel engines have more and more dangerous effect on the nature and on the built environment as well. One of the most important emission-component of a diesel engine running on conventional diesel is particulate matter. For measuring particulate matter there are many different widely used measurement methods. Using biofuel in diesel engines also causes emission of particulate matter. The basic aim of our work was to investigate and to evaluate the conventional biodiesel's and the new type TBK-Biodiesel's effect on the particulate relevant emission of a compression ignition engine. Particulate relevant emission mean in this case the four different measurement methods like filter smoke number, opacity, particulate mass and particulate number. With a rising blending rate of the - in internal combustion engine useable - bio derived fuels (standardized biodiesel and non-standardized TBK-biodiesel) to fossil diesel the particulate relevant emission of the engine changes significantly. The tendencies in particulate relevant emission with growing blending rate are different among the measurement methods. Because of this situation biofuels cannot be evaluated clearly compared to fossil diesel in point of view of particulate relevant emission. Highlights • Diesel, FAME-biodiesel and TBK-biodiesel have been investigated in a CI engine. • Four, different, particulate relevant measurements were used. • Increasing the bio rate to fossil have a significant effect in particulate emission. • Changes in particulate emission show different tendencies among the used methods. [ABSTRACT FROM AUTHOR]

Abstract Nowadays, biodiesel is seen as an alternative fuel to diesel fuel due to its many advantages such as higher density, cetane number and flash point. Although several methods are available for estimating fuel properties of biodiesel-diesel fuel blends, there is still the lack of works on the comparison of regression models and artificial neural networks (ANN) in predicting viscosities of the blends. Therefore, in this work, (1) optimum reaction parameters providing the lowest viscosity were determined for methanolysis of waste cooking oil, (2) waste cooking oil methyl ester was synthesized based on the determined optimum parameters, and it was mixed with diesel fuel on different volume ratios (3) viscosity measurements of the prepared blends were made at the temperature ranges between 273.15 K and 373.15 K , (4) changes in viscosity versus temperature and biodiesel fraction in blend were investigated and the rational model was proposed, finally (5) the predictive capability of rational model was compared to the three-term Vogel model, Bingham model and ANN by fitting to viscosity data measured by the authors and by Geacai et al. According to results, the measured values by the authors and Geacai et al. are the most accurately predicted by the rational model. Highlights • Experimental optimization of transesterification reaction. • Production of waste cooking oil biodiesel having the lowest viscosity. • Effects of biodiesel fraction and temperature on biodiesel-diesel binary blends. • Viscosity prediction capabilities of regression models and ANN. • Rational model for viscosity changes vs. biodiesel fraction and temperature. [ABSTRACT FROM AUTHOR]

Two challenges that have motivated researchers are the mitigation of emissions and a reduction in the reliance on diesel fuel. A potential replacement for diesel is biodiesel, which is derived from animal fat or vegetable oil. The large number of studies on the performance and emission characteristics of biodiesel is notable. In such studies, the noise emissions have seldom been disregarded or treated as a trivial matter. Extending the previously published research by the authors, an experimental investigation was carried out to study the effects of new fuel types on the noise emissions. Blends of Jatropha methyl ester (JME) biodiesel suspended with zinc oxide (ZnO) nanoparticles along with hydrogen (H 2 ) in dual-fuel mode were used as fuel for an experimental diesel engine test rig. The noise levels in decibels (dB) under variations in the biodiesel percentage, nanoparticle size, and flow rates of H 2 at different loads were recorded. It was observed that 20% and 30% JME biodiesel blends suspended with ZnO nanoparticles of 40 nm in size have superior noise attenuation. To avoid a strenuous experimentation, an artificial neural network model was developed for noise prediction with a regression coefficient of 0.9992. [ABSTRACT FROM AUTHOR]

This work was aimed to study droplet combustion which was a foundation of spray combustion. Combustion characteristics of BUT00 (pure biodiesel) and BUT50 (50% n-butanol and 50% biodiesel by mass) were investigated using droplet suspension technology under 1 bar and 900 K. One flame was observed for BUT00 while two flames were observed for BUT50. The flame of BUT00 underwent successively faint luminosity, bright luminosity, soot aggregate and soot spread. The first flame of BUT50 was faint and the second one was similar to that of BUT00 because they were caused by n-butanol and biodiesel combustion respectively. Before the auto-ignition of BUT00, (D/D 0 ) 2 was approximately unchanged at 1.0 and similarity degree (SD) was higher than 97%. Temperature growth rate (TGR) decreased first quickly and then slowly. After the auto-ignition of BUT00, (D/D 0 ) 2 sharply decreased and SD was in the range of 90–97%. The flame heating led to the increase of TGR. For BUT50, obvious fluctuations were found in (D/D 0 ) 2 , SD and TGD. The SD of BUT50 was generally lower than 97%. The (D/D 0 ) 2 of BUT50 included transient heating, fluctuation evaporation and equilibrium evaporation phases. Some characteristic parameters were deterministic although (D/D 0 ) 2 in fluctuation evaporation phase was a non-deterministic process. [ABSTRACT FROM AUTHOR]

Today, the increase in the production and consumption of biofuels such as biodiesel in the transportation sector is considered an appropriate solution to decrease the consumption of fossil fuels and their consequent pollutions. However, in order to increase energy efficiency and minimize energy losses and waste materials, the biodiesel production processes require the particular revisions and modifications. In the present study, the exergy analyses of the mechanical stirrer (MS), ultrasonic cavitation (UC) and hydrodynamic cavitation (HC)-based biodiesel production processes were performed and the results were compared together, in order to improve the efficiency of the biodiesel production process. To compare the results, three parameters of the exergy waste emission, the exergy destruction, and the exergy efficiency were used. The results indicated that both the cavitation processes lead to improved exergy efficiency in the biodiesel production. However, the HC process proved to be a more appropriate option to replace the conventional biodiesel production process equipped with stirred-rank reactors (the MS process) due to eliminating the main waste streams, decreasing exergy destruction to half, and increasing exergy efficiency by 6.2%. [ABSTRACT FROM AUTHOR]

This paper investigates the performance and emission analyses of a turbo-charged diesel engine fuelled with pre-mixed and post-mixed hybrid biodiesel blends at varying load condition thereby maintaining injection timing, injection pressure and speed constant at 23 0 bTDC, 220 bar and 1500 RPM. The experimental result depicted that post-mixed biodiesel blends (POBD 20) showed higher brake specific energy consumption and exhaust gas temperature by 4.6% and 2.02% than that of diesel while brake thermal efficiency was reduced by 5.68%. However, engine overall performance of post-mixed biodiesel blends (POBD 20) was found to be comparable with diesel and other prepared test fuel blends. Similarly, comparing exhaust emissions, oxides of nitrogen and carbon dioxide were on its higher side by 2.64% and 2.43% than normal diesel fuel. On the contrary, carbon monoxide, hydrocarbon and smoke opacity for POBD 20 were found to be 36.87%, 51.5% and 23.2% lower than conventional diesel fuel. From the above study, it is finally concluded that POBD 20 blend may be used as an alternative optional fuel that can substitute present diesel fuel without much engine modification and exhaust related problems. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effect of durability on the regulated and unregulated emissions, as well as the power and fuel economy performance of a biodiesel-powered engine equipped with a diesel oxidation catalyst (DOC) and a selective catalytic reduction (SCR) system based on a 500-h durability test. Furthermore, a BET (Brunauer-Emmett-Teller) test was employed to analyze the specific surface area changes of the DOC and SCR. Results show that after the durability, the power performance improved and the brake-specific fuel consumption (BSFC) reduced due to the running-in effect. Although the deterioration of the DOC and SCR after the durability resulted in an increase in the carbon monoxide (CO), total hydrocarbon (THC) and nitrogen oxide (NO X ) emission factors of the biodiesel-powered engine based on European steady state cycle (ESC) by 41.3%, 36.1% and 39.2%, respectively, these emissions were still below China-Ⅴ limits. For unregulated emissions, the reduced BSFC caused by the durability led to a decrease in the carbon dioxide (CO 2 ) and sulfur dioxide (SO 2 ) emissions, but the durability resulted in higher aldehyde emission. The BET specific surface areas of the DOC and SCR decreased by 40.2% and 35.0%, respectively after the durability, which accounted for their catalytic performance deterioration. [ABSTRACT FROM AUTHOR]

It is known that biodiesel and bioethanol are viable alternative fuels to replace diesel for compression ignition engines. In this study, an experimental investigation is carried out to evaluate the performance and exhaust emissions of a single cylinder diesel engine fuelled with biodiesel-bioethanol-diesel blends. The engine performance parameters evaluated are the brake specific fuel consumption and brake thermal efficiency whereas the exhaust emission parameters evaluated are carbon monoxide, nitrogen oxide, and smoke opacity. Kernel-based extreme learning machine is used to predict the engine performance and exhaust emission parameters of the fuel blends at full throttle conditions. Based on the experimental results, the brake specific fuel consumption is lower while the brake thermal efficiency is higher for the biodiesel-bioethanol-diesel blends. The carbon monoxide emissions and smoke opacity are also lower for these fuel blends. The mean absolute percentage error of the brake specific fuel consumption, brake thermal efficiency, carbon monoxide, nitrogen oxide, and smoke opacity is 1.363, 1.482, 4.597, 2.224, and 2.090%, respectively. Thus, it can be concluded that K-ELM is a reliable method to estimate the engine performance and exhaust emission parameters of a single cylinder compression ignition engine fuelled with biodiesel-bioethanol-diesel blends to reduce fuel consumption and exhaust emissions. [ABSTRACT FROM AUTHOR]

Current research reports the synthesis of in-situ TiO 2 /RGO nanocomposite and used as a heterogeneous catalyst for the transesterification of waste cooking oil into biodiesel. The prepared catalyst was characterized viz. X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), Thermogravimetric analysis (TGA) techniques conforming the successful formation of nanocomposite. The effects of various reaction parameters used for transesterification were examined to optimize the reaction conditions. The best operational conditions were oil to methanol molar ratio of 1:12 at 65 °C with 1.5 wt% catalyst loading and reaction time of 3 h. The catalyst showed good catalytic activity in biodiesel production and biodiesel conversion of 98% was obtained under optimum reaction conditions. Biodiesel conversion was confirmed by Proton Nuclear Magnetic Resonance ( 1 H NMR), Carbon Nuclear Magnetic Resonance ( 13 C NMR) and Gas Chromatography-Mass Spectroscopy (GC-MS) techniques. The excellent catalytic activity of TiO 2 /RGO could be attributed to the enhanced surface area of the composite. [ABSTRACT FROM AUTHOR]

One of the major challenges in the production of biodiesel is the immiscibility of oil and methanol. The extent of dispersion between the two phases controls the mass and heat transfer rates and consequently the rate of the transesterification reaction. In this study, we report a novel design of a batch agitated vessel used for the production of biodiesel from palm oil. The new reactor is provided with static stainless steel mesh screen baffles to promote dispersion between the two immiscible reactants. The effect of the key parameters was investigated. The reaction yield was expressed in terms of FAME (fatty acid methyl ester) concentration. The optimum transesterification reaction conditions that yielded the highest biodiesel yield (97%) were as follows: methanol to oil molar ratio of 6:1, a reaction temperature of 60 °C, a one percent (wt.%) NaOH solution, a mesh screen size of 12″ and an agitation speed of 250 rpm. In order to test whether the produced biodiesel can replace diesel oil in combustion engines we evaluated the biodiesel quality, the engine performance and the emission characteristics of a B20 (20% biodiesel and 80% petroleum diesel) blend. A reduction in carbon monoxide and a marginal increase in nitrogen oxides emissions was observed. [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]