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.     

Exhaust emissions from a diesel powered vehicle fuelled by soybean biodiesel blends (B3-B20) with ethanol as an additive (B20E2-B20E5)

The effects of diesel oil-soybean biodiesel blends on a passenger vehicle exhaust pollutant emissions were investigated. Blends of diesel oil and soybean biodiesel with concentrations of 3% (B3), 5% (B5), 10% (B10) and 20% (B20) were used as fuels. Additionally, the effects of anhydrous ethanol as an additive to B20 fuel blend with concentrations of 2% (B20E2) and 5% (B20E5) were also studied. The emissions tests were carried out following the New European Driving Cycle (NEDC). The results showed that increasing biodiesel concentration in the fuel blend increases carbon dioxide (CO₂) and oxides of nitrogen (NO_X) emissions, while carbon monoxide (CO), hydrocarbons (HC) and particulate matter (PM) emissions are reduced. The addition of anhydrous ethanol to B20 fuel blend proved it can be a strategy to control exhaust NO_X and global warming effects through the reduction of CO₂ concentration. However, it may require fuel injection modifications, as it increases CO, HC and PM emissions.     

Potential for reducing emissions in a diesel engine by fuelling with conventional biodiesel and Fischer-Tropsch diesel

A gas-to-liquid (GTL) fuel derived from Low Temperature Fischer-Tropsch process has been tested in an automotive diesel engine fulfilling Euro 4 emissions regulations. Both regulated and non-regulated emissions have been compared with those of a commercial diesel fuel, a commercial biodiesel fuel and a GTL-biodiesel fuel (30% and 70% v/v, respectively) in order to check blending properties, synergistic effects and compatibility between first and second generation production technologies for biofuel consumption in current diesel engines. After presenting a detailed literature review, and confirming that similar efficiencies are attained with the four tested fuels under identical road-like operating conditions (this meaning fuel consumption is inversely proportional to their heating values), significant reductions in smoke opacity, particulate matter emissions and particle number concentration were observed with both GTL and biodiesel fuels, with small changes in NO_x emissions. Compared with the reductions in PM emissions derived from the use of biodiesel fuels, those derived from using GTL fuels were quite similar, despite its lower soot emissions reductions. This can be explained by the lower volatile organic fraction of the PM in the case of GTL. By adequately blending both fuels, a considerable potential to optimise the engine emissions trade-off is foreseen.     

Characteristics of polycyclic aromatic hydrocarbons emissions of diesel engine fueled with biodiesel and diesel

With mutagenic and carcinogenic potential, polycyclic aromatic hydrocarbons (PAHs) from mobile source exhaust have contributed to a substantial share of air toxics. In order to characterize the PAHs emissions of diesel engine fueled with diesel, biodiesel (B100) and its blend (B20), an experimental study has been carried out on a direct-injection turbocharged diesel engine. The particle-phase and gas-phase PAHs in engine exhaust were collected by fiberglass filters and “PUF/XAD-2/PUF” cartridges, respectively, then the PAHs were determined by a gas chromatograph/mass spectrometer (GC/MS). The experimental results indicated that comparing with diesel, using B100 and B20 can greatly reduce the total PAHs emissions of diesel engine by 19.4% and 13.1%, respectively. The Benzo[a]Pyrene (BaP) equivalent of PAHs emissions were also decreased by 15.0% with the use of B100. For the three fuels, the gas-phase PAHs emissions were higher than particle-phase PAHs emissions and the most abundant PAH compounds from engine exhaust were naphthalene and phenanthrene. The analysis showed that there was a close correlation between total PAHs emissions and particulate matter (PM) emissions for three fuels. Furthermore, the correlation became more significant when using biodiesel.     

Performance of a diesel generator fuelled with palm oil

Pure palm oil may be employed in diesel engines as an alternative fuel. Engine performance and emissions were influenced by basic differences between diesel fuel and palm oils such as mass based heating values, viscosity, density and molecular oxygen content. The high viscosity of palm oil resulted in poor atomisation, carbon deposits, clogging of fuel lines and starting difficulties in low temperatures. When heated at 100 °C palm oil presented lower viscosity, better combustion and less deposits. Tests were conducted in a naturally aspirated MWM 229 direct injection four-stroke 70 kW diesel-generator fueslled with 100% palm oil.     

Fuel properties and emissions of soybean oil esters as diesel fuel

The effects of using blends of methyl and isopropyl esters of soybean oil with No. 2 diesel fuel were studied at several steady-state operating conditions in a four-cylinder turbocharged diesel engine. Fuel blends that contained 20, 50, and 70% methyl soyate and 20 and 50% isopropyl soyate were tested. Fuel properties, such as cetane number, also were investigated. Both methyl and isopropyl esters provided significant reductions in particulate emissions compared with No. 2 diesel fuel. A blend of 50% methyl ester and 50% No. 2 diesel fuel provided a reduction of 37% in the carbon portion of the particulates and 25% in the total particulates. The 50% blend of isopropyl ester and 50% No. 2 diesel fuel gave a 55% reduction in carbon and a 28% reduction in total particulate emissions. Emissions of carbon monoxide and unburned hydrocarbons also were reduced significantly. Oxides of nitrogen increased by 12%.     

Cetane number effect on the energetic and exergetic efficiency of a diesel engine fuelled with biodiesel

This study presents the energy, exergy and heat release analysis of a John Deere 4045 T 4.5 L, four-stroke, four-cylinder, turbocharged diesel engine. The engine was run with four different types of fuel: yellow grease methyl ester (YGME); soybean oil methyl ester (SME); and soybean oil methyl ester containing either 0.75 or 1.5 w/w % of the cetane improver 2-ethylhexyl nitrate (SME-0.75%EHN and SME-1.5%EHN, respectively). The engine was tested at 1400 1/min under a full load of 352 Nm. For reliability, the fuels were tested three times, and the mean values were compared using different statistical techniques. The objective in this study was to determine the effect of cetane number and ignition delay on the energy and exergy efficiencies of an internal combustion engine and to compare the results for the types of fuel stated earlier. The average thermal efficiency was approximately 40.5%, and the exergetic efficiency was approximately 37.3%. The mean exergetic efficiencies of the fuels were in the order ψ_SME > ψ_SME-0.75%EHN > ψ_SME-1.5%EHN > ψ_YGME. There were significant differences among the mean values according to Student's t-tests. It is concluded that a lower cetane number, a longer ignition delay period and a higher level of premixed combustion may increase the exergetic efficiency of a diesel engine.     

Engine-out characterisation using speed-load mapping and reduced test cycle for a light-duty diesel engine fuelled with biodiesel blends

In this two-phase experimental programme, key effects of different biodiesel fuels and their blends on engine-out responses of a light-duty diesel engine were investigated. Here, coconut methyl ester (CME), palm methyl ester (PME) and soybean methyl ester (SME) were tested to represent the wide spectrum of degree of saturations in the fatty acid composition. Fossil diesel which served as the blending component was used as the baseline fuel for benchmarking purposes. Phase I examined how engine speed and load affect patterns of variation in tailpipe emissions and engine performance parameters for the test fuels. Here, the trends in engine-out responses across the operational speed-load map for all the tested biodiesel fuels were similar and consistent throughout. However, there were marked differences in the levels of equivalence ratio and specific fuel consumption, as well as exhaust concentrations of CO, UHC and smoke opacity. This is mainly due to differences in fuel properties, especially fuel-bound oxygen content, density and impurity level. Phase II appraised the performance of 31 different fuel blend combinations of fossil diesel blended with CME, PME or SME at 10 vol.% interval under a steady-state test cycle. The use of biodiesel fuels with low to moderate degree of unsaturation was found to conclusively reduce regulated emission species of UHC, NO and smoke opacity levels by up to 41.7%, 5.4% and 61.3%, respectively. This is in contrast to the performance of the highly unsaturated SME, where CO, UHC, NO and smoke opacity levels are higher in relation to that of fossil diesel. Simultaneous NO-smoke reduction can be achieved through the introduction of at least 1 vol.% of PME or 50 vol.% of CME into diesel fuel, although minor trade-off in the higher specific fuel consumption is observed.     

Biodiesel blend effects on common-rail diesel combustion and emissions

Biodiesel (fatty acid methylesters) blends with fossil diesel at a mixing ratio between 0.5 and 5 vol.% are widely offered as automotive fuels in Europe. The target for the future is to bring this ratio to at least 10%, in order to increase the share of renewable energy in transport. There is however limited evidence on the effects of such blends on the combustion and emissions of diesel engines not originally designed to operate on biodiesel blends. In this study, a number of experiments with 10 vol.% (B10) biodiesel fuel of palmoil origin were performed on a light-duty common-rail Euro 3 engine. The measurements included in-cylinder pressure, pollutants emissions, and fuel consumption. Combustion effects were limited but changes in the start of ignition and heat-release rate could be identified. Emission effects included both higher and lower smoke and NOx, depending on the operation point. The results on the engine bench were compared against a Euro 3 common-rail light-duty vehicle driven on the chassis dynamometer, in order to include the effects of emission control systems (EGR and oxidation catalyst). In addition to the palm biodiesel, an RME-diesel blend was also tested to examine the effects of a fuel with different characteristics. Both biodiesel blends reduced PM emissions and only marginal effects on NOx over the certification test could be identified. The results of this study show that up to 10% biodiesels could be used on current diesel vehicles, without significantly affecting vehicle emission performance.     

Comparative study of performance and emissions of a diesel engine using Chinese pistache and jatropha biodiesel

An experimental study of the performances and emissions of a diesel engine is carried out using two different biodiesels derived from Chinese pistache oil and jatropha oil compared with pure diesel. The results show that the diesel engine works well and the power outputs are stable running with the two selected biodiesels at different loads and speeds. The brake thermal efficiencies of the engine run by the biodiesels are comparable to that run by pure diesel, with some increases of fuel consumptions. It is found that the emissions are reduced to some extent when using the biodiesels. Carbon monoxide (CO) emissions are reduced when the engine run at engine high loads, so are the hydrocarbon (HC) emissions. Nitrogen oxides (NOx) emissions are also reduced at different engine loads. Smoke emissions from the engine fuelled by the biodiesels are lowered significantly than that fuelled by diesel. It is also found that the engine performance and emissions run by Chinese pistache are very similar to that run by jatropha biodiesel.     

Combustion and emissions of a DI diesel engine fuelled with diesel-oxygenate blends

Combustion and emissions of a DI diesel engine fuelled with diesel-oxygenate blends were investigated. The results show that there exist the different behaviors in the combustion between the diesel-diglyme blends and the other five diesel-oxygenate blends as the diglyme has the higher cetane number than that of diesel fuel while the other five oxygenates have the lower cetane number than that of diesel fuel. The smoke concentration decreases regardless of the types of oxygenate additives, and the smoke decreases with the increase of the oxygen mass fraction in the blends without increasing the NO_x and engine thermal efficiency. The reduction of smoke is strongly related to the oxygen-content of blends. CO and HC concentrations decrease with the increase of oxygen mass fraction in the blends. Unlike conventional diesel engines fueled with pure diesel fuel, engine operating on the diesel-oxygenate blends presents a flat NO_x/Smoke tradeoff curve versus oxygen mass fraction.     

Effect of biodiesel blends on North American heavy‐duty diesel engine emissions

We conducted an assessment of North American heavy‐duty engine emission test results for biodiesel from 49 experimental studies, including both engine dynamometer and vehicle test results. Comparison with a commercial database showed that the engines in the emissions database are not representative of the existing North American in‐use fleet as of 2007; more than 50% of the tested engines were of 1995 or earlier vintage. Nevertheless, the results show that the use of a common biodiesel blend (B20) consistently reduces emissions of particulate matter, hydrocarbons, and carbon monoxide by 10–20%. Tests with B20 show varying effects on oxides of nitrogen (NO_x). If results for pre‐1992 two‐cycle 6V‐92TA(E) engines (which represent 0.2% of the 2007 in‐use fleet but 28% of the engines tested) are removed, then there is no statistical evidence that the average NO_x emissions from B0 and B20 are different (p value of 0.50 for an estimated average increase of 1%). Several researchers have used changes in engine calibration to eliminate any NO_x penalty associated with B20 (in engines that show an increase in NO_x with B20), while still maintaining the advantages of B20 in reducing other pollutants. The emissions effect of B20 on heavy‐duty diesel truck emissions did not show any correlation with model year or type of fuel injection equipment.     

Comparison of emissions of a direct injection diesel engine operating on biodiesel with emulsified and fumigated methanol

Biodiesel is an alternative fuel for internal combustion engines. It can reduce carbon monoxide (CO), hydrocarbon (HC) and particulate matter (PM) emissions, compared with diesel fuel, but there is also an increase in nitrogen oxides (NO_x) emission. This study is aimed to compare the effect of applying a biodiesel with either 10% blended methanol or 10% fumigation methanol. The biodiesel used in this study was converted from waste cooking oil. Experiments were performed on a 4-cylinder naturally aspirated direct injection diesel engine operating at a constant speed of 1800 rev/min with five different engine loads. The results indicate a reduction of CO₂, NO_x, and particulate mass emissions and a reduction in mean particle diameter, in both cases, compared with diesel fuel. It is of interest to compare the two modes of fueling with methanol in combination with biodiesel. For the blended mode, there is a slightly higher brake thermal efficiency at low engine load while the fumigation mode gives slightly higher brake thermal efficiency at medium and high engine loads. In the fumigation mode, an extra fuel injection control system is required, and there is also an increase in CO, HC and NO₂ (nitrogen dioxide) and particulate emissions in the engine exhaust, which are disadvantages compared with the blended mode.     

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.     

Effect of alternative fuels on exhaust emissions during diesel engine operation with matched combustion phasing

The present work focuses on an experimental comparison of diesel emissions produced by three fuels: an ultra low sulfur diesel fuel (BP15), a pure soybean methyl-ester biodiesel fuel (B100), and a synthetic Fischer-Tropsch fuel (FT), practically free of sulfur and aromatic compounds, and produced in a gas-to-liquid process. The study was carried out using a 2.5 L direct injection common-rail turbodiesel engine operated at 2400 rpm and 64 N m torque (19% of maximum torque). The engine was tested with single and split (pilot and main) injections and without exhaust gas recirculation (EGR). The study has two objectives. The first objective is to investigate the impact of the start of injection (SOI) on performance and emissions of each fuel. The second objective is to study the isolated impacts of the test fuels on pollutant emissions by adjusting the injection parameters (SOI and fuel rail pressure) for each fuel, while producing practically the same combustion phasing. When the combustion phasing occurs similarly, this study has confirmed that the FT fuel can reduce all regulated diesel emissions under both single and split injection strategies. Finally, it has been confirmed that biodiesel can reduce particle mean diameter in comparison with BP15. However, higher PM mass emission for B100 has been observed under the condition of matched combustion phasing. The increase of the PM mass emission is probably due to the unburned or partially burned hydrocarbon (HC) emissions.     

Effects of biodiesel on a DI diesel engine performance, emission and combustion characteristics

Experimental tests were investigated to evaluate the performance, emission and combustion of a diesel engine using neat rapeseed oil and its blends of 5%, 20% and 70%, and standard diesel fuel separately. The results indicate that the use of biodiesel produces lower smoke opacity (up to 60%), and higher brake specific fuel consumption (BSFC) (up to 11%) compared to diesel fuel. The measured CO emissions of B5 and B100 fuels were found to be 9% and 32% lower than that of the diesel fuel, respectively. The BSFC of biodiesel at the maximum torque and rated power conditions were found to be 8.5% and 8% higher than that of the diesel fuel, respectively. From the combustion analysis, it was found that ignition delay was shorter for neat rapeseed oil and its blends tested compared to that of standard diesel. The combustion characteristics of rapeseed oil and its diesel blends closely followed those of standard diesel.     

Regulated and unregulated emissions from a light-duty diesel engine with different sulfur content fuels

Five different sulfur content fuels were used on a light-duty diesel engine to study the effect of fuel sulfur on emissions. Four regulated emissions: smoke, nitrogen oxide (NO_x), unburned hydrocarbon (HC) and carbon monoxide (CO) emissions of the engine were investigated, as well as three unregulated emissions: formaldehyde (HCHO), acetaldehyde (MECHO) and sulfur dioxide (SO₂). The smoke emission decreases continuously and remarkably with the fuel sulfur content, and the fuel sulfur has more influence on smoke emission at lower engine load. The concentration of NO_x emissions did not change significantly with the different sulfur content fuels. As the fuel sulfur content decreases, the concentrations of HC and CO emissions have distinct reduction. The HCHO emission values are very low. The MECHO emission decreases with increasing engine load, and it continuously decreases with the fuel sulfur content and it could not be detected at higher engine load with 50 ppm sulfur fuel. The SO₂ emission increases continuously with the engine load, and obviously decreases with the fuel sulfur contents.     

Performance and emission study of waste anchovy fish biodiesel in a diesel engine

Waste anchovy fish oils transesterification was studied with the purpose of achieving the conditions for biodiesel usage in a single cylinder, direct injection compression ignition. With this purpose, the pure biodiesel produced from anchovy fish oil, biodiesel-diesel fuel blends of 25%:75% biodiesel-diesel (B25), 50%:50% biodiesel-diesel (B50), 75%:25% biodiesel-diesel (B75) and petroleum diesel fuels were used in the engine to specify how the engine performance and exhaust emission parameters changed. The fuel properties of test fuels were analyzed. Tests were performed at full load engine operation with variable speeds of 1000, 1500, 2000 and 2500 rpm engine speeds. As results of investigations on comparison of fuels with each other, there has been a decrease with 4.14% in fish oil methyl ester (FOME) and its blends' engine torque, averagely 5.16% reduction in engine power, while 4.96% increase in specific fuel consumption have been observed. On one hand there has been average reduction as 4.576%, 21.3%, 33.42% in CO₂, CO, HC, respectively; on the other hand, there has been increase as 9.63%, 29.37% and 7.54% in O₂, NO_x and exhaust gas temperature has been observed. It was also found that biodiesel from anchovy fish oil contains 37.93 wt.% saturated fatty acids which helps to improve cetane number and lower NO_x emissions. Besides, for biodiesel and its blends, average smoke opacity was reduces about 16% in comparison to D2. It can be concluded that waste anchovy fish obtained from biodiesel can be used as a substitute for petroleum diesel in diesel engines.     

Emissions from different alternative diesel fuels operating with single and split fuel injection

Few factors affect diesel combustion and emissions more significantly than the composition of the fuel and the fuel injection process. In this paper, both of these factors are considered by comparing conventional, synthetic and vegetable oil-derived diesel fuels and by comparing a single pulse injection and a split (pilot and main) injection process. This paper focuses on characterization of the combustion process and emissions produced by three substantially different diesel fuels: an ultra low sulfur diesel fuel (BP15), a pure soybean methyl ester (B100), and a synthetic, practically free of sulfur and aromatic compounds, Fischer-Tropsch fuel (FT) produced in a gas-to-liquid process. The study was carried out in a direct injection (DI) 2.5 L common-rail turbodiesel engine working at four engine operation modes, spanning conditions of most interest in the engine map. In all modes the engine was tested with single and split injection (pilot and main), with constant start of injection (SOI), and without exhaust gas recirculation (EGR). Using the results from thermodynamic analysis, this study confirms that the ignition character of the fuel affects the start of the combustion process, notably for the whole combustion process when the single injection is used, and during the combustion process after the pilot injection when the split injection is used. In general, the FT fuel can reduce both NOx and PM specific emissions in all modes under both single and split injection modes, bypassing the nitrogen oxides-particulate matter (NOx-PM) trade-off. Finally, this work confirms that biodiesel can reduce the particle concentration. However, in some cases an increase of PM mass emission has been observed and this increase of the PM mass emission is due to unburned or partially burned hydrocarbon (HC) emissions.     

The effect of temperature and pressure on the physicochemical properties of petroleum diesel oil and biodiesel fuel

Three commercial fuels were studied: biodiesel (based mainly of the fatty acids methyl esters of rapeseed oil), diesel oil Ekodiesel Ultra (standard petroleum diesel oil with sulphur content less than 10 mg/kg), and ON BIO 10 (blend of 20 vol.% of biodiesel with 80 vol.% of standard petroleum diesel oil with sulphur content less than 10 mg/kg). The speeds of sound were measured within the temperatures from 293 to 318 K and at pressures from 0.1 to 101 MPa. The densities and heat capacities were measured under atmospheric pressure in the temperature range from 273 to 363 K and 283 to 359 K, respectively. Using the experimental results, the physicochemical properties such as: density, isentropic bulk modulus, heat capacity, and isobaric thermal expansion were calculated in the same temperature and pressure range as the speed of sound was measured. The results obtained show that although the bulk modulus of ON BIO 10 is higher than that of diesel oil Ekodiesel Ultra over the whole pressure range, the difference is rather small and can be compensated by temperature. Isobaric thermal expansivity of biodiesel decreases with pressure slightly less than that of the diesel oil Ekodiesel Ultra. It is approximately independent of temperature and composition of the fuel at pressures 40 ± 5 MPa.