Formulation of Canola-Diesel Microemulsion Fuels and Their Selective Diesel Engine Performance

Vegetable oils have been considered as an alternative to diesel fuel due to their comparable properties and performance. However, the high viscosity of vegetable oil causes engine durability problems with long-term usage. Vegetable oil viscosity can be reduced by blending with diesel fuel in thermodynamically stable mixtures using microemulsion fuel formulation techniques. This work focuses on the formulation of microemulsion fuels comprising diesel fuel and canola oil as the oil phase with ethanol and sec-butanol as viscosity reducers as well as 1-octanol and oleyl amine as surfactant/cosurfactant. Selective tests on an instrumented diesel engine were performed for formulated microemulsion fuels and No. 2 diesel fuel for comparison. The results show that formulated microemulsion fuels have fuel properties that meet the ASTM requirements for viscosity, cloud point, and pour point for biodiesel. Even more important, they have phase stability over a wide range of temperatures (−10 to 70 °C). Although all of the microemulsion fuels showed higher fuel consumption than diesel fuel, some of the microemulsion fuels had significantly reduced CO and NO_x emissions as well as reduced particulates when compared to baseline diesel fuel. The research demonstrates the potential of these microemulsion fuels as alternative to neat diesel fuel.     

Combustion, performance and emission characteristics of a DI diesel engine fueled with ethanol-biodiesel blends

In this study, Euro V diesel fuel, biodiesel, and ethanol-biodiesel blends (BE) were tested in a 4-cylinder direct-injection diesel engine to investigate the combustion, performance and emission characteristics of the engine under five engine loads at the maximum torque engine speed of 1800 rpm. The results indicate that when compared with biodiesel, the combustion characteristics of ethanol-biodiesel blends changed; the engine performance has improved slightly with 5% ethanol in biodiesel (BE5). In comparison with Euro V diesel fuel, the biodiesel and BE blends have higher brake thermal efficiency. On the whole, compared with Euro V diesel fuel, the BE blends could lead to reduction of both NO_x and particulate emissions of the diesel engine. The effectiveness of NO_x and particulate reductions increases with increasing ethanol in the blends. With high percentage of ethanol in the BE blends, the HC, CO emissions could increase. But the use of BE5 could reduce the HC and CO emissions as well.     

Solubility of a diesel–biodiesel–ethanol blend,its fuel properties,and its emission characteristics from diesel engine

In this work, we studied the phase diagram of diesel–biodiesel–ethanol blends at different purities of ethanol and different temperatures. Fuel properties (such as density, heat of combustion, cetane number, flash point and pour point) of the selected blends and their emissions performance in a diesel engine were examined and compared to those of base diesel. It was found that the fuel properties were close to the standard limit for diesel fuel; however, the flash point of blends containing ethanol was quite different from that of conventional diesel. The high cetane value of biodiesel could compensate for the decrease of the cetane number of the blends caused by the presence of ethanol. The heating value of the blends containing lower than 10% ethanol was not significantly different from that of diesel. As for the emissions of the blends, it was found that CO and HC reduced significantly at high engine load, whereas NO_x increased, when compared to those of diesel. Taking these facts into account, a blend of 80% diesel, 15% biodiesel and 5% ethanol was the most suitable ratio for diesohol production because of the acceptable fuel properties (except flash point) and the reduction of emissions.     

Stability of diesel–bioethanol blends for use in diesel engines

Bioethanol is an attractive fuel due to its renewable origin and its oxygen content, but it is unable to be used directly in diesel engines. Although biodiesel can be produced with bioethanol through ethanolisis, direct blending of ethanol and diesel fuel, called e-diesel, has at least the same potential to reduce particulate emissions, despite their much lower production cost. The main drawback is that ethanol is immiscible with diesel fuel over a wide range of temperatures, leading to phase separation. Consequently, in many cases the presence of a surfactant and cosolvent additive in the e-diesel blend becomes necessary. In this paper the conditions in which the e-diesel blends are stable have been studied. The stability of samples is affected by three factors mainly: temperature, water content and initial ethanol content. The results show that the presence of water in the blends, low temperatures and high ethanol contents favour the phase separation whereas the presence of the additive leads to the opposite effect. These effects have been quantified through level curve maps for stability and for separation time.     

Influence of Methanol–Biodiesel Blends on the Particulate Emissions of a Direct Injection Diesel Engine

In this study, Euro V diesel fuel, biodiesel, and methanol–biodiesel blends were tested in a 4-cylinder direct-injection diesel engine to investigate the combustion characteristics and particulate emissions of the diesel engine under five engine loads at the maximum torque engine speed of 1800 rpm. Compared with Euro V diesel fuel, biodiesel gives lower and earlier heat release rate. For the blended fuels, the peak heat release rate becomes higher and retarded. With regard to particulate mass concentration, biodiesel generates less than Euro V diesel fuel, while the blended fuels result in significant reduction especially at high engine loads. Compare with Euro V diesel fuel, the total particle number concentration of using biodiesel is always higher while the geometric mean diameter (GMD) of the particles is lower. With the blended fuel, the total number concentration and GMD decrease in comparison with pure biodiesel. Further analysis shows that the difference between the total number concentration of biodiesel and Euro V diesel fuel is in particles smaller than 50 nm rather than in the larger particles. The use of methanol–biodiesel blends, compared with biodiesel, could reduce the number concentration of all sizes. A comparison between the particulate mass emission and total particulate number concentration with the mass of fuel burned in the diffusion mode show that they are strongly related to each other, even for the blended fuel.     

Fuel consumption and emissions from a diesel power generator fuelled with castor oil and soybean biodiesel

This work investigates the impacts on fuel consumption and exhaust emissions of a diesel power generator operating with biodiesel. Fuel blends with 5%, 20%, 35%, 50%, and 85% of soybean biodiesel in diesel oil, and fuel blends containing 5%, 20%, and 35% of castor oil biodiesel in diesel oil were tested, varying engine load from 9.6 to 35.7 kW. Specific fuel consumption (SFC) and the exhaust concentrations of carbon dioxide (CO₂), carbon monoxide (CO), and hydrocarbons (HC) were evaluated. The engine was kept with its original settings for diesel oil operation. The results showed increased fuel consumption with higher biodiesel concentration in the fuel. Soybean biodiesel blends showed lower fuel consumption than castor biodiesel blends at a given concentration. At low and moderate loads, CO emission was increased by nearly 40% and over 80% when fuel blends containing 35% of castor oil biodiesel or soybean biodiesel were used, respectively, in comparison with diesel oil. With the load power of 9.6 kW, the use of fuel blends containing 20% of castor oil biodiesel or soybean biodiesel increased HC emissions by 16% and 18%, respectively, in comparison with diesel oil. Exhaust CO₂ concentration did not change significantly, showing differences lower than ±3% of the values recorded for diesel oil operation, irrespective of biodiesel type, concentration and the load applied. The results demonstrate that optimization of fuel injection system is required for proper engine operation with biodiesel.     

Study of oxygenated biomass fuel blends on a diesel engine

Vegetable methyl ester was added in ethanol–diesel fuel to prevent separation of ethanol from diesel in this study. The ethanol blend proportion can be increased to 30% in volume by adding the vegetable methyl ester. Engine performance and emissions characteristics of the fuel blends were investigated on a diesel engine and compared with those of diesel fuel. Experimental results show that the torque of the engine is decreased by 6%–7% for every 10% (by volume) ethanol added to the diesel fuel without modification on the engine. Brake specific fuel consumption (BSFC) increases with the addition of oxygen from ethanol but equivalent brake specific fuel consumption (EBSFC) of oxygenated fuels is at the same level of that of diesel. Smoke and particulate matter (PM) emissions decrease significantly with the increase of oxygen content in the fuel. However, PM reduction is less significant than smoke reduction. In addition, PM components are affected by the oxygenated fuel. When blended fuels are used, nitrogen oxides (NO_x) emissions are almost the same as or slightly higher than the NO_x emissions when diesel fuel is used. Hydrocarbon (HC) is apparently decreased when the engine was fueled with ethanol–ester–diesel blends. Fuelling the engine with oxygenated diesel fuels showed increased carbon monoxide (CO) emissions at low and medium loads, but reduced CO emissions at high and full loads, when compared to pure diesel fuel.     

Aviation fuel JP-5 and biodiesel on a diesel engine

Naval aviation turbine fuel, JP-5, has been accepted as alternative to JP-8 in the frame of the Single Fuel Policy. This has resulted in some ongoing research on JP-5 fuel for its application as a naval single fuel. The necessity to cope with the environmental problems identified in the process of implementing the Single Fuel Policy as well as the strict requirements of modern diesel engines has lead to the need of improved single fuel quality. The development of biomass derived substitutes for diesel, such as biodiesel, is a possible attractive solution. The present paper is an effort to evaluate JP-5 along with diesel and biodiesel for use in a diesel engine. These fuels were used alone and in various mixture fractions in a single cylinder stationary diesel engine in order to evaluate their performance under defined operating conditions of the engine. JP-5 reduced both the NOx and particulate matter emissions as compared to the reference fuel case. Biodiesel significantly lowered particulate emissions, but slightly increased NOx emissions and fuel consumption. Fuel sulfur content has an undesired effect on smoke opacity. Biodiesel increased the fuel consumption when added to petroleum fuels and the increase was larger at high engine loads. Diesel and JP-5 showed similar fuel consumption, with diesel consumption increasing at high engine loads. Ternary blends showed similar behavior. The blends with lower biodiesel content showed lower volumetric fuel consumption.     

A comparative study on the performance, emission and combustion studies of a DI diesel engine using distilled tyre pyrolysis oil–diesel blends

Alternate fuels like ethanol, biodiesel, LPG, CNG, etc., have been already commercialised in the transport sector. In this context, pyrolysis of solid waste is currently receiving renewed interest. The disposal of waste tyres can be simplified to a certain extent by pyrolysis. In the present work, the crude tyre pyrolyisis oil (TPO) was desulphurised and then distilled through vacuum distillation. Also, two distilled tyre pyrolysis oil (DTPO)–diesel fuel (DF) blends at lower and higher concentrations were used as fuels in a four stroke single cylinder air cooled diesel engine without any engine modification. The results were compared with diesel fuel (DF) operation. Results indicate that the engine can run with 90% DTPO and 10% diesel fuel.     

The kinematic viscosity of biodiesel and its blends with diesel fuel

As the use of biodiesel becomes more wide-spread, engine manufacturers have expressed concern about biodiesel’s higher viscosity. In particular, they are concerned that biodiesel may exhibit different viscosity-temperature characteristics that could result in higher fuel injection pressures at low engine operating temperatures. This study presents data for the kinematic viscosity of biodiesel and its blends with No. 1 and No. 2 diesel fuels at 75, 50, and 20% biodiesel, from close to their melting point to 100°C. The results indicate that while their viscosity is higher, biodiesel and its blends demonstrate temperature-dependent behavior similar to that of No. 1 and No. 2 diesel fuels. Equations of the same general form are shown to correlate viscosity data for both biodiesel and diesel fuel, and for their blends. A blending equation is presented that allows the kinematic viscosity to be calculated as a function of the biodiesel fraction.     

Numerical analysis of injection characteristics using biodiesel fuel

This paper deals with numerical analysis of injection process using biodiesel/mineral diesel fuel blends with the aim to search for the potentials to reduce engine harmful emissions. The considered fuels are neat biodiesel from rapeseed oil and its blends with mineral diesel D2. For the numerical analysis a one-dimensional mathematical model is employed. In order to model accurately the investigated fuels, the employed empirical expressions for their properties are determined by experiments. To verify the mathematical model and the empirical expressions, experiments and numerical simulation are run on a mechanical control diesel fuel injection M system at several operating regimes. Injection process at many different operating regimes and using several fuel blends are then investigated numerically. Attention is focused on the injection characteristics, especially on fuelling, fuelling at some stage of injection, mean injection rate, mean injection pressure, injection delay and injection timing, which influence the most important engine characteristics. The analysis of the obtained results reveals that, while keeping engine performance within acceptable limits, harmful emissions can be reduced by adjusting appropriately pump injection timing in dependence on the biodiesel content. This prediction is also confirmed experimentally.     

Physical and chemical properties of ethanol-diesel fuel blends

This paper discusses the physical-chemical properties of ethanol-diesel fuel blends. The attention is focused on the properties which influence the injection and engine characteristics significantly. Main properties have been investigated experimentally. The analysis of experimentally obtained fuel properties of tested fuels and their influence on engine characteristics are presented. Physical and chemical properties of diesel fuel and ethanol-diesel fuel blends were measured according to requirements and test methods for diesel fuel (EN590, 2003). The tested fuels were neat mineral diesel fuel (D100), 5% (v/v) ethanol/diesel fuel blend (E05D95), 10% (v/v) ethanol-diesel fuel blend (E10D90) and 15% (v/v) ethanol-diesel fuel blend (E15D85). It has been proved that, for ethanol-diesel fuel blends, some additives are necessary to keep stability under low temperature conditions. Also, cold weather properties test, such as cloud point and pour point tests are negatively affected by phase separation. The rest of the properties, excepting flash point, were within diesel fuel standard specifications. Based on this study, it can be concluded that using additives to avoid phase separation and to raise flash point, blends of diesel fuel with ethanol up to 15% can be used to fuel diesel engines if engine performance tests corroborate it.     

Performance and emission characteristics of an CI engine fueled with diesel–biodiesel–bioethanol blends

The paper presents the experimental results obtained concerning performances and pollution of a diesel engine fueled with diesel–biodiesel–ethanol blends compared with diesel fuel in laboratory tests. The main properties of the researched fuels are presented within this paper, in comparison with classical diesel fuel (chemical composition, density, kinematic viscosity, cold filter plugging point, flash point). Engines’ performances were evaluated by determining the brake specific fuel consumption and brake thermal efficiency. For pollution evaluation the emissions of CO, CO₂, NO_x, HC and smoke have been measured. An increasing of brake specific fuel consumption has been observed, especially at lower engines’ loads, with maximum 32.4%, reducing engine brake thermal efficiency with maximum 21.7%. CO emissions decrease, especially at high loads with maximum 59%, on the basis of CO₂ increased emissions. NO_x emissions slightly increase, especially at partial and high loads, meanwhile HC and smoke emissions decrease in all engines’ load cycles.     

Experimental investigation on injection characteristics of bioethanol-diesel fuel and bioethanol-biodiesel blends

This paper analyses the fuel injection characteristics of bioethanol-diesel fuel and bioethanol-biodiesel blends considered as fuel for diesel engines. Attention is focused on the injection characteristics which significantly influence the engine characteristics and subsequently the exhaust emissions. In this context the following injection characteristics have been investigated experimentally: fuelling, injection timing, injection delay, injection duration, mean injection rate, and injection pressure. The tested fuels were neat mineral diesel fuel, neat biodiesel made from rapeseed oil, bioethanol/diesel fuel and bioethanol/biodiesel blends up to 15% (v/v) bioethanol with an increment of 5%. The fuels blends were experimentally investigated in a fuel injection M system at rated condition (FL, 1100 rpm), peak torque (FL, 850 rpm), and maximum pump speed (1100 rpm) for different partial loads (PL 75% and PL 50%), at ambient temperature.It has been proven that for all operating regimens tested, the addition of bioethanol to biodiesel reduces fuelling, injection timing, injection duration, mean injection rate and maximum injection pressure and increases injection delay compared to pure biodiesel. Meanwhile, increasing bioethanol in diesel fuel shows no significant variations or a slightly increase in fuelling, injection timing, injection duration, and mean injection rate and a decrease in injection delay and maximum injection pressure, compared to pure diesel fuel.The influence of bioethanol in biodiesel is much more significant that in diesel fuel; it has a beneficial effect on biodiesel injection characteristics because bioethanol addition brings them nearer to the diesel fuel one and it is expected to decrease biodiesel NO_x emissions.     

Cold start and fuel consumption of a vehicle fuelled with blends of diesel oil–soybean biodiesel–ethanol

Fuel consumption and cold start characteristics of a production vehicle fuelled with blends of N. 2 diesel oil (500 ppm sulfur content), soybean biodiesel (3%, 5%, 10%, and 20%) and hydrous ethanol (2% and 5%) were compared. A wagon-type vehicle equipped with a four-cylinder, 1.3-l, 63 kW diesel engine was tested in a cold chamber at the temperature of −5 °C for the cold start tests. Fuel consumption tests were performed following the 1975 US Federal Test Procedure (FTP-75). The results showed that the cold start time was satisfactory for all fuel blends tested, but it was longer for the blend containing 20% of soybean biodiesel (B20) in comparison with the blends with lower biodiesel concentration. The cold start time also increased with increasing with increasing ethanol content in the fuel blend. Specific fuel consumption was not affected by increasing biodiesel concentration in the blend or by the use of 2% of ethanol as an additive. However, the use of 5% of ethanol concentration in the B20 blend resulted in increased specific fuel consumption.     

Emission characteristics of diesel, gas to liquid, and biodiesel-blended fuels in a diesel engine for passenger cars

The need for diversification of energy sources and reducing various emissions including CO₂ emission in diesel engine can be met with alternative diesel fuels such as gas to liquid (GTL) and GTL–biodiesel blends. But there should be a clear understanding of the combustion and engine-out emission characteristics for alternative fuels. In this respect, an experimental study was conducted on a 2.0 L 4 cylinders turbocharged diesel engine fuelled with those alternative diesel fuels to investigate the engine-out emission characteristics under various steady-state engine operating conditions. The results revealed that noticeable decreases in THC (22–56%) and CO (16–52%) emissions for GTL–biodiesel blends were observed, whereas NOx emissions for GTL–biodiesel blends increased by a maximum of 12% compared to diesel. With regard to particle size distributions (PSDs) for GTL–biodiesel blends, the particulate matter (PM) number concentration in accumulation mode decreased, as a result of the excess oxygen content in biodiesel. Contrary to the tendency in the accumulation mode, there was a slight increase in the PM number concentration in the nucleation mode under the operating conditions wherein the exhaust gas recirculation (EGR) strategy was applied. The total PM number concentration for G + BD40 decreased by a maximum of 46% compared to that for diesel. From these results of enhanced emission characteristics compared to diesel and GTL fuel, the potential for the use of GTL–biodiesel blends could be confirmed.     

Diesel engine evaluation of a nonionic sunflower oil-aqueous ethanol microemulsion

A nonionic sunflower oil-aqueous ethanol microemulsion was formulated, characterized and evaluated as a fuel in a direct injection, turbocharged, intercooled, 4-cylinder Allis-Chalmers diesel engine during a 200 hr EMA cycle laboratory screening endurance test. Differences in engine operation between a baseline Phillips 2D reference fuel and the experimental fuel were observed. The major problem experienced while operating with the microemulsion was an incomplete combustion process at low-load engine operation. Significant lubricating oil dilution was observed initially, followed by an abnormal increase in the viscosity of the lubricative oil. Heavier carbon residue on the piston lands, in the piston ring grooves and in the intake ports was noted. In addition, premature injection-nozzle deterioration (sticking of the needle) was experienced. At present, the sunflower oil-aqueous ethanol microemulsion studied cannot be recommended for long-term use in a direct-injection diesel engine, but further modifications in formulation may produce acceptable sunflower oil microemulsions as alternative diesel fuels. Presented at the AOCS meeting, Chicago, IL, May 1983.     

柴油-生物柴油-乙醇溶解性及其调和燃料特性的研究

以自制的生物柴油为助溶剂,研究了生物柴油对乙醇和柴油调和燃料的助溶作用;研究了不同比例的柴油-生物柴油-乙醇调和燃料的理化特性及稳定性。结果表明,当生物柴油含量为12.55%时,柴油和燃料乙醇可以以任意比例互溶;乙醇含量过高会导致燃料的各种理化性能下降;乙醇含量为10%,生物柴油含量>12.55%为混合燃料较为适宜的调和比列。     

Scrubbing effect on diesel particulate matter from transesterified waste oils blends

The objective of this work is to understand the impact of biodiesel chemical structure, specifically fatty acid composition on particulate matter formation, particularly on the retention of hydrocarbons by soot due to the scrubbing effect and absorption processes.A typical diesel fuel supplied in petrol stations, two biofuels composed of methyl esters from the transesterification process of waste oils with different origins and some blends of biofuels with the reference fuel were tested in a commercial direct injection engine reproducing five modes of the European transient urban/extraurban certification cycle.The values of parameters related to the scrubbing effect and the absorption process were evaluated and fitted using neural networks (NNs). Simulation from NNs equations proves that in the case of tested fuels, the amount of palmitic acid methyl ester (PME) is the main factor affecting the amount of soluble material retained due to scrubbing. PME produces a lower amount of particulates, which reduces the agglomeration process and increases their specific surface. It is also proved that sulphur in sulphates (well known to be responsible for the scrubbing effect) must mainly come from the oil lube since the use of biofuels and their mixtures eliminates or significantly reduces sulphur concentration in the fuel, respectively. Condensation onto the particles due to inadequate vaporization and significant unburned biofuel must also be considered.The absorption process during particle formation was found to be negligible when biofuels were tested.     

Biodiesel from safflower oil and its application in a diesel engine

Safflower seed oil was chemically treated by the transesterification reaction in methyl alcohol environment with sodium hydroxide (NaOH) to produce biodiesel. The produced biodiesel was blended with diesel fuel by 5% (B5), 20% (B20) and 50% (B50) volumetrically. Some of important physical and chemical fuel properties of blend fuels, pure biodiesel and diesel fuel were determined. Performance and emission tests were carried out on a single cylinder diesel engine to compare biodiesel blends with petroleum diesel fuel. Average performance reductions were found as 2.2%, 6.3% and 11.2% for B5, B20 and B50 fuels, respectively, in comparison to diesel fuel. These reductions are low and can be compensated by a slight increase in brake specific fuel consumption (Bsfc). For blends, Bsfcs were increased by 2.8%, 3.9% and 7.8% as average for B5, B20 and B50, respectively. Considerable reductions were recorded in PM and smoke emissions with the use of biodiesel. CO emissions also decreased for biodiesel blends while NO_x and HC emissions increased. But the increases in HC emissions can be neglected as they have very low amounts for all test fuels. It can be concluded that the use of safflower oil biodiesel has beneficial effects both in terms of emission reductions and alternative petroleum diesel fuel.