Regulated and unregulated emissions from a diesel engine fueled with biodiesel and biodiesel blended with methanol

Experiments were carried out on a diesel engine operating on Euro V diesel fuel, pure biodiesel and biodiesel blended with methanol. The blended fuels contain 5%, 10% and 15% by volume of methanol. Experiments were conducted under five engine loads at a steady speed of 1800 rev min⁻¹ to assess the performance and the emissions of the engine associated with the application of the different fuels. The results indicate an increase of brake specific fuel consumption and brake thermal efficiency when the diesel engine was operated with biodiesel and the blended fuels, compared with the diesel fuel. The blended fuels could lead to higher CO and HC emissions than biodiesel, higher CO emission but lower HC emission than the diesel fuel. There are simultaneous reductions of NO_x and PM to a level below those of the diesel fuel. Regarding the unregulated emissions, compared with the diesel fuel, the blended fuels generate higher formaldehyde, acetaldehyde and unburned methanol emissions, lower 1,3-butadiene and benzene emissions, while the toluene and xylene emissions not significantly different.     

Experimental investigation of regulated and unregulated emissions from a diesel engine fueled with Euro V diesel fuel and fumigation methanol

Experiments were conducted on a four-cylinder direct-injection diesel engine with part of the engine load taken up by fumigation methanol injected into the air intake of each cylinder to investigate the regulated and unregulated gaseous emissions and particulate emission of the engine under five engine loads at an engine speed of 1920 rev min^?1. The fumigation methanol was injected to top up 10%, 20% and 30% of the engine load under different engine operating conditions.The experimental results show that at low engine loads, the brake thermal efficiency (BTE) decreases with increase in fumigation methanol; but at high engine loads, the BTE is not significantly affected by fumigation methanol. The fumigation methanol results in significant increase in hydrocarbon (HC), carbon monoxide (CO) and nitrogen dioxide (NO₂) emissions, but decrease in nitrogen oxides (NO_x). For the unregulated gaseous emissions, unburned methanol, formaldehyde and BTX (benzene, toluene and xylene) emissions increase but ethyne, ethene and 1,3-butadiene emissions decrease. Particulate mass and number concentrations also decrease with increase in fumigation methanol. A diesel oxidation catalyst (DOC) is found to reduce significantly most of the pollutants, including the air toxics, when the exhaust gas temperature is sufficiently high.     

Regulated and unregulated emissions from an internal combustion engine operating on ethanol-containing fuels

In the present work, the effect of ethanol addition to gasoline on regulated and unregulated emissions is studied. A 4-cylinder OPEL 1.6 L internal combustion engine equipped with a hydraulic brake dynamometer was used in all the experiments. For exhaust emissions treatment a typical three-way catalyst was used. Among the various compounds detected in exhaust emissions, the following ones were monitored at engine and catalyst outlet: methane, hexane, ethylene, acetaldehyde, acetone, benzene, 1,3-butadiene, toluene, acetic acid and ethanol. Addition of ethanol in the fuel up to 10% w/w had as a result an increase in the Reid vapour pressure of the fuel, which indicates indirectly increased evaporative emissions, while carbon monoxide tailpipe emissions were decreased. For ethanol-containing fuels, acetaldehyde emissions were appreciably increased (up to 100%), especially for fuel containing 3% w/w ethanol. In contrast, aromatics emissions were decreased by ethanol addition to gasoline. Methane and ethanol were the most resistant compounds to oxidation while ethylene was the most degradable compound over the catalyst. Ethylene, methane and acetaldehyde were the main compounds present at engine exhaust while methane, acetaldehyde and ethanol were the main compounds in tailpipe emissions for ethanol fuels after the catalyst operation.     

Emission profile of 18 carbonyl compounds,CO, CO2, and NOx emitted by a diesel engine fuelled with diesel and ternary blends containing diesel,ethanol and biodiesel or vegetable oils

The impact of vehicular emissions on air depends, among other factors, on the composition of fuel and the technology used to build the engines. The reduction of vehicular emissions requires changes in the fuel composition, and improving the technologies used in the manufacturing of engines and for the after-treatment of gases. In general, improvements to diesel engines have targeted not only emission reductions, but also reductions in fuel consumption. However, changes in the fuel composition have been shown to be a more rapid and effective alternative to reduce pollution. Some factors should been taken into consideration when searching for an alternative fuel to be used in diesel engines, such as emissions, fuel stability, availability and its distribution, as well as its effects on the engine durability. In this work, 45 fuel blends were prepared and their stability was evaluated. The following mixtures (v/v/v) were stable for the 90-day period and were used in the emission study: diesel/ethanol – 90/10%, diesel/ethanol/soybean biodiesel – 80/15/5%, diesel/ethanol/castor biodiesel – 80/15/5%, diesel/ethanol/residual biodiesel – 80/15/5%, diesel/ethanol/soybean oil – 90/7/3%, and diesel/ethanol/castor oil – 90/7/3%. The diesel/ethanol fuel showed higher reduction of NO_x emission at a lower load (2 kW) when compared with pure diesel. The other fuels showed a decrease of NO_x emissions in the ranges of 6.9–75% and 4–85% at 1800 rpm and 2000 rpm, respectively. The combustion efficiencies of the diesel can be enhanced by the addition of the oxygenate fuels, like ethanol and biodiesel/vegetable oil, resulting in a more complete combustion in terms of NO_x emission. In the case of CO₂ the decreases were in the ranges of 5–24% and 4–6% at 1800 rpm and 2000 rpm, respectively. Meanwhile, no differences were observed in CO emission. The carbonyl compounds (CC) studied were formaldehyde, acetaldehyde, propionaldehyde, acrolein, acetone, crotonaldehyde, butyraldehyde, butanone, benzaldehyde, isovaleraldehyde, valeraldehyde, o-toluenaldehyde, m-toluenaldehyde, p-toluenaldehyde, hexaldehyde, octaldehyde, 2,5-dimethylbenzaldehyde, and decaldehyde. Among them, formaldehyde, acetaldehyde, acetone, and propionaldehyde showed the highest emission concentrations. When ternary blend contains vegetable oil, there is a strong tendency to increase the emissions of the high weight CC and decrease the emissions of the low weight CC. The highest concentration of acrolein was observed when the fuel contains diesel, ethanol and biodiesel. With the exception of NO_x, the use of ternary blended fuels resulted on the increase in the emission rates of the studied compounds.     

Enhancement in combustion,performance, and emission characteristics of a diesel engine fueled with diesel,biodiesel, and its blends by using nanoadditive

This article presents the results of investigations carried out to evaluate the improvement in combustion, performance, and emission characteristics of a diesel engine fueled with neat petro-diesel (PD), soybean biodiesel (SB), and 50% SB blended PD (PD50SB) by using carbon nanotube (CNT) as an additive. The acid–alkaline-based transesterification process with sodium hydroxide (NaOH) as a catalyst was applied to derive the methyl ester of SB. A mass fraction of 100 ppm CNT nanoparticle was blended with base fuels by using an ultrasonicator and the physiochemical properties were measured based on EN standards. The measured physiochemical properties are in good agreement with standard limits. The experimental evaluations were carried out under varying brake mean effective pressure (BMEP) conditions in a single-cylinder, four-stroke, and natural aspirated research diesel engine at a constant speed of 1500 rpm. The results reveal that the SB and its blend promote shorter ignition delay period (IDP) that is resulting in lower in-cylinder pressure (ICP) and net heat release rate (NHR) compared to PD. The SB and its blend increase the brake specific fuel consumption (BSFC), and reduce the brake specific energy consumption (BSEC) and exhaust gas temperature (EGT), due to lower heating value, and efficient combustion, respectively. As far as the emission characteristics are concerned, the SB and its blend promote lower magnitude of hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO₂), and smoke emissions compared to PD except for oxides of nitrogen (NO_x) emission. The CNT nanoparticle inclusion with base fuels significantly improves the combustion, performance, and emissions level irrespective of engine load conditions.

     

Speciated Hydrocarbon and Carbon Monoxide Emissions from an Internal Combustion Engine Operating on Methyl Tertiary Butyl Ether-Containing Fuels

ABSTRACT

In the present work, engine and tailpipe (after a three-way catalytic converter) emissions from an internal combustion engine operating on two oxygenated blend fuels [containing 2 and 11% weight/weight (w/w) methyl tertiary butyl ether (MTBE)] and on a nonoxygenated base fuel were characterized. The engine (OPEL 1.6 L) was operated under various conditions, in the range of 0-20 HP. Total unburned hydrocarbons, carbon monoxide, methane, hexane, ethylene, acetaldehyde, acetone, 2-propanol, benzene, toluene, 1,3-butadiene, acetic acid, and MTBE were measured at each engine operating condition. As concerns the total HC emissions, the use of MTBE was beneficial from 1.90 to 3.81 HP, which were by far the most polluting conditions. Moreover, CO emissions in tailpipe exhaust were decreased in the whole operation range with increasing MTBE in the fuel.

The greatest advantage of MTBE addition to gasoline was the decrease in ethylene, acetaldehyde, benzene, toluene, and acetic acid emissions in engine exhaust, especially when MTBE content in the fuel was increased to 11% w/w. In tailpipe exhaust, the catalyst operation diminished the observed differences. Ethylene, methane,and acetaldehyde were the main compounds present in exhaust gases. Ethylene was easily oxidized over the catalyst,while acetaldehyde and methane were quite resistant to oxidation.     

Influence of Oxygenated Fuels on the Emissions from Three Pre-1985 Light-Duty Passenger Vehicles

Tailpipe and evaporative emissions from three pre-1985 passenger motor vehicles operating on an oxygenated blend fuel and on a nonoxygenated base fuel were characterized. Emission data were collected for vehicles operating over the Federal Test Procedure at 40,75, and 90°F to simulate ambient driving conditions. The two fuels tested were a commercial summer grade regular gasoline (the nonoxygenated base fuel) and an oxygenated fuel containing 9.5 percent methyl tert-butyl ether (MTBE), more olefins, and fewer aromatics than the base fuel. The emissions measured were total hydrocarbons (THCs), speciated hydrocarbons, speciated aldehydes, carbon monoxide (CO), oxides of nitrogen (NO_x), benzene, and 1,3-butadiene.

This study showed no pattern of tailpipe regulated emission reduction when oxygenated fuel was used. Tailpipe emissions from the 1984 Buick Century without a catalyst and the 1977 Mustang with catalyst decreased with the MTBE fuel. However, emissions from the 1984 Buick Century and the 1980 Chevrolet Citation, both fitted with catalysts increased. The vehicles emitted more 1,3- butadiene and, in general, more NO_x when operated with the base fuel.

THC, CO, benzene, and 1,3-butadiene emissions from both fuels and all vehicles, in general, decreased with increasing test temperature, whereas NO_x emissions, in general, increased with increasing test temperature. Formaldehyde, acetaldehyde, and total aldehydes also showed a decrease in emissions as test temperature increased. More formaldehyde was emitted when the MTBE fuel was used.

Evaporative, diurnal, and hot soak emissions from the base fuel were greater than those from the MTBE fuel. The evaporated emissions from both fuels increased with increasing test temperatures. Diurnal data indicate that canister conditioning (bringing the evaporative charcoal canister to equilibrium) is required before testing.     

Speciated hydrocarbon and carbon monoxide emissions from an internal combustion engine operating on methyl tertiary butyl ether-containing fuels

In the present work, engine and tailpipe (after a three-way catalytic converter) emissions from an internal combustion engine operating on two oxygenated blend fuels [containing 2 and 11% weight/weight (w/w) methyl tertiary butyl ether (MTBE)] and on a nonoxygenated base fuel were characterized. The engine (OPEL 1.6 L) was operated under various conditions, in the range of 0-20 HP. Total unburned hydrocarbons, carbon monoxide, methane, hexane, ethylene, acetaldehyde, acetone, 2-propanol, benzene, toluene, 1,3-butadiene, acetic acid, and MTBE were measured at each engine operating condition. As concerns the total HC emissions, the use of MTBE was beneficial from 1.90 to 3.81 HP, which were by far the most polluting conditions. Moreover, CO emissions in tailpipe exhaust were decreased in the whole operation range with increasing MTBE in the fuel. The greatest advantage of MTBE addition to gasoline was the decrease in ethylene, acetaldehyde, benzene, toluene, and acetic acid emissions in engine exhaust, especially when MTBE content in the fuel was increased to 11% w/w. In tailpipe exhaust, the catalyst operation diminished the observed differences. Ethylene, methane, and acetaldehyde were the main compounds present in exhaust gases. Ethylene was easily oxidized over the catalyst, while acetaldehyde and methane were quite resistant to oxidation.     

Speciated Hydrocarbon Emissions from the Combustion of Single Component Fuels. I. Effect of Fuel Structure

Speciated hydrocarbon emissions data have been collected for six single-component fuels run in a laboratory pulse flame combustor (PFC). The six fuels include n-heptane, isooctane (2, 2, 4-trimethylpentane), cyclohexane, 1-hexene, toluene, and methyl-t-butyl ether (MTBE: an oxygenated fuel extender). Combustion of non-aromatic fuels in the PFC (at a fuel/air equivalence ratio of Φ = 1.02) produced low levels of unburned fuel and high yields of methane and olefins (> 75 percent combined) irrespective of the molecular structure of the fuel. In contrast, hydrocarbon emissions from toluene combustion in the PFC were comprised predominantly of unburned fuel (72 percent). With the PFC, low levels of 1, 3-butadiene (0.3-1.8 percent) were observed from all the fuels except MTBE, for which no measurable level (<0.2 percent) was detected; low levels of benzene were observed from isooctane, heptane, and 1-hexene, but significant levels (9 percent) from cyclohexane and toluene. No measurable amount of benzene (< 0.2 percent) was observed in the MTBE exhaust.

For isooctane and toluene the speciated hydrocarbon emissions from a spark-ignited (SI) single-cylinder engine were also determined. HC emissions from the SI engine contained the same species as observed from the PFC, although the relative composition was different. For the non-aromatic fuel isooctane, unburned fuel represented a larger fraction (50 percent) of the HC emissions when run in the engine. HC emissions from toluene combustion in the engine were similar to those from the PFC.     

Effects of biodiesel made from swine and chicken fat residues on carbon monoxide,carbon dioxide,and nitrogen oxide emissions

The effects of two alternative sources of animal fat-derived biodiesel feedstock on CO₂, CO, NO_x tailpipe emissions as well as fuel consumption were investigated. Biodiesel blends were produced from chicken and swine fat waste (FW-1) or floating fat (FW-2) collected from slaughterhouse wastewater treatment processes. Tests were conducted in an unmodified stationary diesel engine operating under idling conditions in attempt to simulate slow traffic in urban areas. Significant reductions in CO (up to 47% for B100; FW-2) and NO_x (up to 20% for B5; FW-2 or B100; FW-1) were attained when using biodiesel fuels at the expense of 5% increase in fuel consumption. Principal component analysis (PCA) was performed to elucidate possible associations among gas (CO₂, CO, and NO_x) emissions, cetane number and iodine index with different sources of feedstock typically employed in the biodiesel industry. NO_x, cetane number and iodine index were inversely proportional to CO₂ and biodiesel concentration. High NO_x emissions were reported from high iodine index biodiesel derived especially from forestry, fishery and some agriculture feedstocks, while the biodiesel derived from animal sources consistently presented lower iodine index mitigating NO_x emissions. The obtained results point out the applicability of biodiesel fuels derived from fat-rich residues originated from animal production on mitigation of greenhouse gas emissions. The information may encourage practitioners from biodiesel industry whilst contributing towards development of sustainable animal production.

Implications: Emissions from motor vehicles can contribute considerably to the levels of greenhouse gases in the atmosphere. The use of biodiesel to replace or augment diesel can not only decrease our dependency on fossil fuels but also help decrease air pollution. Thus, different sources of feedstocks are constantly being explored for affordable biodiesel production. However, the amount of carbon monoxide (CO), carbon dioxide (CO₂), and/or nitrogen oxide (NO_x) emissions can vary largely depending on type of feedstock used to produce biodiesel. In this work, the authors demonstrated animal fat feasibility in replacing petrodiesel with less impact regarding greenhouse gas emissions than other sources.     

Quantification of personal exposure concentrations to gasoline vehicle emissions in high-end exposure microenvironments: Effects of fuel and season

Mobile-source air toxic (MSAT) levels increase in confining microenvironments (MEs) with numerous emission sources of vehicle exhaust or evaporative emissions or during high-load and cold-start conditions. Reformulated fuels are expected to reduce MSAT and ozone precursor emissions. This study, required under the Clean Air Act Section 211b, evaluated high-end exposures in cities using reformulated (methyl tertiary-butyl ether [MTBE] or ethanol [EtOH]) fuels and conventional gasoline blends. The study investigates 13 high-end MEs, sampling under enhanced exposure conditions expected to result in maximal fuel and exhaust component exposures to carbon monoxide (CO), carbon dioxide (CO₂), BTEX (benzene, toluene, ethylbenzene, xylenes), MTBE, 1,3-butadiene (1,3-BD), EtOH, formaldehyde (HCHO), and acetaldehyde (CH₃CHO). The authors found that day-to-day ME variations in high-end benzene, 1,3-BD, HCHO, and CO concentrations are substantial, but independent of gasoline composition and season, and related to the activity and emission rates of ME sources, which differ from day to day.

Implications: Mobile-source air toxic (MSAT) levels increase in confining microenvironments (MEs) in the presence of vehicular exhaust or evaporative emissions. This study, required under the Clean Air Act Section 211b, evaluated high-end exposures in cities using oxygenated (methyl tertiary-butyl ether or ethanol) and conventional gasoline blends. Personal exposure concentrations were quantified in selected MEs representing the upper end of the frequency distribution of potential population exposures. This work presents the first systematic look at high-end/maximal exposures to multiple contaminants, in multiple microenvironments, in multiple cities, over two seasons, for multiple fuels, making it a very complete evaluation of reformulated fuel impacts on MSAT concentrations in confined microenvironments. The study found that day-to-day ME variations of high-end pollutant concentrations are substantial, but independent of gasoline composition and season, and related to the variable daily activity and emission rates of ME sources. The data collected in this study may be used in bounding exposure modeling estimates that account for time spent in similar confining MEs.     

Seasonal impact of blending oxygenated organics with gasoline on motor vehicle tailpipe and evaporative emissions.

Emissions from a 1988 GM Corsica with adaptive learning closed loop control were measured with 4 fuels at 40, 75, and 90 degrees F. Evaporative and exhaust emissions were examined from each fuel at each test temperature. Test fuels were unleaded summer grade gasoline; a blend of this gasoline containing 8.1 percent ethanol; a refiner's blend stock; and the blend stock containing 16.2 percent methyl tertiary butyl ether. The ethanol and MTBE blends contained 3.0 percent oxygen by weight. Regulated emissions (total hydrocarbons, carbon monoxide, and oxides of nitrogen), detailed aldehydes, detailed hydrocarbons, ethanol, MTBE, benzene, and 1,3-butadiene were determined. The highest levels of regulated emissions were produced at the lower temperature. Blended fuels produced almost twice the evaporative hydrocarbon emissions at high temperatures as did the base fuels. Benzene emissions varied with fuels and operating temperatures, while 1,3-butadiene emissions decreased slightly with increasing temperatures. Formaldehyde emissions were not sensitive to fuel or temperature changes. Ethanol fuel blend total aldehyde emissions increased by 40 percent due to increased acetaldehyde emissions. Fuel blends had approximately a 3 percent economy decrease. The MTBE fuel blend appeared to offer the most reduction in total hydrocarbon, carbon monoxide, and oxides of nitrogen for the fuels and temperatures tested.     

Germany

ABSTRACT

The 1988 Alternative Motor Fuels Act and the 1990 Clean Air Act Amendments require examination of the potential to favorably influence air quality by changing the composition of motor vehicle fuels. Motor vehicle tailpipe and evaporative emissions were characterized using laboratory simulations of roadway driving conditions and a variety of vehicle-fuel technologies (reformulated gasoline (RFG), methanol (M85), ethanol (E85), and natural gas (CNG)). Speciated organic compound (with Carter MIR ozone potential), CO, and NO_x emission rates and fuel economy were characterized. The Carter MIR ozone potential of combined Federal Test Procedure (FTP) tailpipe and evaporative emissions was reduced more than 90% with CNG relative to RFG, M85, and E85 fuels. FTP toxic compound emissions (benzene, formaldehyde, acetalde-hyde, and 1,3-butadiene) were greater with M85 and E85 fuels than with RFG fuel, and less with CNG fuel than RFG fuel. The most abundant toxic compound was benzene with RFG fuel, formaldehyde with M85 fuel, and acetaldehyde with E85 fuel. FTP MPG fuel economies were reduced with M85 and E85 fuels relative to RFG fuel, consistent with their lower BTU/gal. Energy efficiencies (BTU/mi) were improved with all the alternative fuels relative to RFG. Carter MIR ozone potential was generally reduced with the alternative fuels relative to RFG fuel under REP05 (high speeds and acceleration rates) driving conditions (most significantly with CNG). Toxic aldehyde emissions were reduced under REP05 conditions relative to FTP conditions with all the tested fuels, and toxic benzene emissions were elevated under high acceleration conditions.     

Modelling and assessing trends in traffic-related emissions using a generalised additive modelling approach

A generalised additive modelling (GAM) approach is used to model daily concentrations of nitrogen oxides (NO_X), nitrogen dioxide (NO₂), carbon monoxide (CO), benzene and 1,3-butadiene at a busy street canyon location in central London. The models were developed for the period July 1998–June 2005 using appropriate meteorological and road traffic covariates. For all models, the complex and localised wind-flow patterns resulting from the street canyon location of the monitoring site, which can be difficult to model deterministically, have a large influence on the model predictions. It is shown that GAMs built using simple covariates explain a large amount of the daily variation for these pollutants (mean r²=0.86). It is found that concentrations of benzene and 1,3-butadiene have declined in line with detailed calculations of emissions trends, with some evidence to suggest that reductions in benzene have been greater than estimated reductions in emissions. Although measured concentrations of NO_X have declined from 1998 to 2005, much of the decline appears to be associated with reductions in overall traffic and meteorological factors rather than reduced emissions of NO_X. Unadjusted NO_X trends show a 28.6% reduction (95% confidence interval from 21.2% to 35.8%) from 1998 to 2005, whereas meteorologically adjusted trends show a 19.3% decline (95% confidence interval from 14.8% to 23.5%) over this period. Analysis shows that there were a higher number of occasions in the early part of the time series that led to strong recirculation of exhaust emissions and higher NO_X concentrations at this location, thus affecting observed trends in concentration.     

Study of Miller timing on exhaust emissions of a hydrotreated vegetable oil (HVO)-fueled diesel engine

The effect of intake valve closure (IVC) timing by utilizing Miller cycle and start of injection (SOI) on particulate matter (PM), particle number, and nitrogen oxide (NO_x) emissions was studied with a hydrotreated vegetable oil (HVO)-fueled nonroad diesel engine. HVO-fueled engine emissions, including aldehyde and polyaromatic hydrocarbon (PAH) emissions, were also compared with those emitted with fossil EN590 diesel fuel. At the engine standard settings, particle number and NO_x emissions decreased at all the studied load points (50%, 75%, and 100%) when the fuel was changed from EN590 to HVO. Adjusting IVC timing enabled a substantial decrease in NO_x emission and combined with SOI timing adjustment somewhat smaller decrease in both NO_x and particle emissions at IVC??50 and??70 °CA points. The HVO fuel decreased PAH emissions mainly due to the absence of aromatics. Aldehyde emissions were lower with the HVO fuel with medium (50%) load. At higher loads (75% and 100%), aldehyde emissions were slightly higher with the HVO fuel. However, the aldehyde emission levels were quite low, so no clear conclusions on the effect of fuel can be made. Overall, the study indicates that paraffinic HVO fuels are suitable for emission reduction with valve and injection timing adjustment and thus provide possibilities for engine manufacturers to meet the strictening emission limits.

Implications: NO_x and particle emissions are dominant emissions of diesel engines and vehicles. New, biobased paraffinic fuels and modern engine technologies have been reported to lower both of these emissions. In this study, even further reductions were achieved with engine valve adjustment combined with novel hydrotreated vegetable oil (HVO) diesel fuel. This study shows that new paraffinic fuels offer further possibilities to reduce engine exhaust emissions to meet the future emission limits.

Supplementary Materials: Supplementary materials are available for this paper. Go to the publisher's online edition of the Journal of the Air & Waste Management Association for a complete list of analysed PAH compounds.     

Effects of diesel/biodiesel blends on regulated and unregulated pollutants from a passenger vehicle operated over the European and the Athens driving cycles

This paper presents the regulated and unregulated exhaust emissions of a diesel passenger vehicle, operated with low sulphur automotive diesel and soy methyl ester blends. Emission and fuel consumption measurements were conducted under real driving conditions (Athens Driving Cycle, ADC) and compared with those of a modified New European Driving Cycle (NEDC) using a chassis dynamometer. A Euro II compliant diesel vehicle was used in this study, equipped with an indirect injection diesel engine, fuelled with diesel fuel and biodiesel blends at proportions of 5, 10, and 20% respectively. Unregulated emissions of 11 polycyclic aromatic hydrocarbons (PAHs), 5 nitro-PAHs, 13 carbonyl compounds (CBCs) and the soluble organic fraction (SOF) of the particulate matter were measured. Qualitative hydrocarbon analysis was also performed on the SOF. Regulated emissions of NO_x, CO, HC, CO₂, and PM were also measured over the two test cycles. It was established that some of the emissions measured over the (hot-start) NEDC differed from the real-world cycle. Significant differences were also observed in the vehicle's fuel consumption between the two test cycles. The addition of biodiesel reduced the regulated emissions of CO, HC and PM, while an increase in NO_x was observed over the ADC. Carbonyl emissions, PAHs and nitro-PAHs were reduced with the addition of biodiesel over both driving cycles.     

Seasonal Impact of Blending Oxygenated Organics with Gasoline on Motor Vehicle Tailpipe and Evaporative Emissions

Emissions from a 1988 GM Corsica with adaptive learning closed loop control were measured with 4 fuels at 40, 75, and 90° F. Evaporative and exhaust emissions were examined from each fuel at each test temperature. Test fuels were unleaded summer grade gasoline; a blend of this gasoline containing 8.1 percent ethanol; a refiner’s blend stock; and the blend stock containing 16.2 percent methyl tertiary butyl ether. The ethanol and MTBE blends contained 3.0 percent oxygen by weight. Regulated emissions (total hydrocarbons, carbon monoxide, and oxides of nitrogen), detailed aldehydes, detailed hydrocarbons, ethanol, MTBE, benzene, and 1, 3-butadiene were determined.

The highest levels of regulated emissions were produced at the lower temperature. Blended fuels produced almost twice the evaporative hydrocarbon emissions at high temperatures as did the base fuels. Benzene emissions varied with fuels and operating temperatures, while 1, 3-butadiene emissions decreased slightly with increasing temperatures. Formaldehyde emissions were not sensitive to fuel or temperature changes. Ethanol fuel blend total aldehyde emissions Increased by 40 percent due to increased acetaldehyde emissions.

Fuel blends had approximately a 3 percent economy decrease. The MTBE fuel blend appeared to offer the most reduction in total hydrocarbon, carbon monoxide, and oxides of nitrogen for the fuels and temperatures tested.     

Toxic Emissions from Mobile Sources: A Total Fuel-Cycle Analysis for Conventional and Alternative Fuel Vehicles

ABSTRACT

Mobile sources are among the largest contributors of four hazardous air pollutants—benzene, 1,3-butadiene, acetal-dehyde, and formaldehyde—in urban areas. At the same time, federal and state governments are promoting the use of alternative fuel vehicles as a means to curb local air pollution. As yet, the impact of this movement toward alternative fuels with respect to toxic emissions has not been well studied. The purpose of this paper is to compare toxic emissions from vehicles operating on a variety of fuels, including reformulated gasoline (RFG), natural gas, ethanol, methanol, liquid petroleum gas (LPG), and electricity. This study uses a version of Argonne National Laboratory's Greenhouse Gas, Regulated Emissions, and Energy Use in Transportation (GREET) model, appropriately modified to estimate toxic emissions. The GREET model conducts a total fuel-cycle analysis that calculates emissions from both downstream (e.g., operation of the vehicle) and upstream (e.g., fuel production and distribution) stages of the fuel cycle. We find that almost all of the fuels studied reduce 1,3-buta-diene emissions compared with conventional gasoline (CG). However, the use of ethanol in E85 (fuel made with 85% ethanol) or RFG leads to increased acetaldehyde emissions, and the use of methanol, ethanol, and compressed natural gas (CNG) may result in increased formaldehyde emissions. When the modeling results for the four air toxics are considered together with their cancer risk factors, all the fuels and vehicle technologies show air toxic emission reduction benefits.     

Impacts of Biodiesel on Pollutant Emissions of a JP-8–Fueled Turbine Engine

Abstract

The impacts of biodiesel on gaseous and particulate matter (PM) emissions of a JP-8–fueled T63 engine were investigated. Jet fuel was blended with the soybean oil-derived methyl ester biofuel at various concentrations and combusted in the turbine engine. The engine was operated at three power settings, namely ground idle, cruise, and takeoff power, to study the impact of the biodiesel at significantly different pressure and temperature conditions. Particulate emissions were characterized by measuring the particle number density (PND; particulate concentration), the particle size distribution, and the total particulate mass. PM samples were collected for off-line analysis to obtain information about the effect of the biodiesel on the polycyclic aromatic hydrocarbon (PAH) content. In addition, temperature-programmed oxidation was performed on the collected soot samples to obtain information about the carbonaceous content (elemental or organic). Major and minor gaseous emissions were quantified using a total hydrocarbon analyzer, an oxygen analyzer, and a Fourier Transform IR analyzer. Test results showed the potential of biodiesel to reduce soot emissions in the jet-fueled turbine engine without negatively impacting the engine performance. These reductions, however, were observed only at the higher power settings with relatively high concentrations of biodiesel. Specifically, reductions of ～15% in the PND were observed at cruise and takeoff conditions with 20% biodiesel in the jet fuel. At the idle condition, slight increases in PND were observed; however, evidence shows this increase to be the result of condensed uncombusted biodiesel. Most of the gaseous emissions were unaffected under all of the conditions. The biodiesel was observed to have minimal effect on the formation of polycyclic aromatic hydrocarbons during this study. In addition to the combustion results, discussion of the physical and chemical characteristics of the blended fuels obtained using standard American Society for Testing and Materials (ASTM) fuel specifications methods are presented.     

Particulate Emissions from a Stationary Engine Fueled with Ultra-Low-Sulfur Diesel and Waste-Cooking-Oil-Derived Biodiesel

ABSTRACT

Stationary diesel engines, especially diesel generators, are increasingly being used in both developing countries and developed countries because of increased power demand. Emissions from such engines can have adverse effects on the environment and public health. In this study, particulate emissions from a domestic stationary diesel generator running on ultra-low-sulfur diesel (ULSD) and biodiesel derived from waste cooking oil were characterized for different load conditions. Results indicated a reduction in particulate matter (PM) mass and number emissions while switching diesel to biodiesel. With increase in engine load, it was observed that particle mass increased, although total particle counts decreased for all the fuels. The reduction in total number concentration at higher loads was, however, dependent on percentage of biodiesel in the diesel-biodiesel blend. For pure biodiesel (B100), the reduction in PM emissions for full load compared to idle mode was around 9%, whereas for ULSD the reduction was 26%. A large fraction of ultrafine particles (UFPs) was found in the emissions from biodiesel compared to ULSD. Nearly 90% of total particle concentration in biodiesel emissions comprised ultrafine particles. Particle peak diameter shifted from a smaller to a lower diameter with increase in biodiesel percentage in the fuel mixture.

IMPLICATIONS There has been an increased usage of stationary diesel engines, especially backup power generators to meet the growing energy demand. Biodiesel derived from waste cooking oil has received increasing attention as an alternative fuel. However, data are only sparsely available in the literature on particulate emissions from stationary engines, fueled with blends of diesel and biodiesel. This study provides insights into the influence of waste-cooking-oil-derived biodiesel on engine performance and the particulate emissions from a stationary engine. The results of the study form a scientific basis to evaluate the impact of biodiesel emissions on the environment and human health.