Browse Topic: Gasohol

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Estimation of the Fuel Efficiency Potential of Six Gasoline Blendstocks Identified by the U.S. Department of Energy’s Co-Optimization of Fuels and Engines Program2019-01-00171/15/2019
Six blendstocks identified by the Co-Optimization of Fuels & Engines Program were used to prepare fuel blends using a fixed blendstock for oxygenate blending and a target RON of 97. The blendstocks included ethanol, n-propanol, isopropanol, isobutanol, diisobutylene, and a bioreformate surrogate. The blends were analyzed and used to establish interaction factors for a non-linear molar blending model that was used to predict RON and MON of volumetric blends of the blendstocks up to 35 vol%. Projections of efficiency increase, volumetric fuel economy increase, and tailpipe CO2 emissions decrease were produced using two different estimation techniques to evaluate the potential benefits of the blendstocks. Ethanol was projected to provide the greatest benefits in efficiency and tailpipe CO2 emissions, but at intermediate levels of volumetric fuel economy increase over a smaller range of blends than other blendstocks. A bioreformate surrogate blendstock was projected to provide the greatest increase in volumetric fuel economy and the lowest increase in efficiency. Tailpipe CO2 emissions for blends of the bioreformate surrogate were higher at all blend levels compared to the baseline E10 fuel.
Sluder, C. Scott
Integrated AHP and WED Based Approach to Select Optimal Combination of Operating Parameters on Spark Ignition Engine2019-01-00251/15/2019
The influence of operating parameters on the performance of spark ignition engine has attracted the interest of engine manufacturers and researchers. In this instance, selection of optimum criteria of operating parameters based on experimental results is expressed as a multi attribute decision making (MADM) problem. In this study, a mathematical model which is an integration of Analytic hierarchy process (AHP) and Weighted Euclidean distance based approach (WED) is proposed to select optimal combination of operating parameters. The parameters chosen are compression ratio (6,7,8,9), fuel blends (E10, E20, E30, E40) and load (25%, 50%, 75%, 100%). Consistency check of weights of attributes was carried out by AHP and the weighted distance of attributes from the most and least favorable situations was evaluated using WED. Optimum criteria with the combination of compression ratio of 8, fuel blend of E20 at load of 100% was found to be optimum. The results of proposed mathematical model were compared with another MCDM tool, Graph theory matrix approach. The proposed model allows the decision maker to analyze and evaluate the weights of attributes logically and systematically to make decision.
Geetha, Narayanan Kannaiyan, Pappula, Bridjesh
Study of Gasoline Particulate Matter Index with Refinery Blends2018-01-03544/3/2018
Gasoline direct injection (GDI) engines can help meet future fuel economy standards but will also make future proposed particulate matter (PM) emissions targets challenging to meet. This is mainly due to the fundamental change in the combustion process in GDI engines compared to conventional port fuel injection (PFI) engines. Auto manufacturers have linked PM emissions to gasoline formulations. Researchers at the Honda Motor Company proposed the particulate matter index (PMI) as a measure for gasoline sooting tendency. In this paper, 59 gasoline blend stocks from seven refineries were collected in order to study the compositional effect of real refinery streams on gasoline PMI. 580 gasoline blends were made from the 59 blend stocks. No traditional metrics of fuel quality were found to correlate well with the PMI. Reformate and FCC Naphtha contribute most significantly to the PMI of gasoline. Based on the refinery modeling assumptions presented in this paper, it is shown that a decrease in PMI from 1.5 to 1.35 shrinks the gasoline pool by 10%; a decrease in PMI from 1.5 to 1.0 yields a reduction of 30%. Since reformate is the primary incremental octane supply in a refinery, increasing the base octane from 87 [R + M]/2 E10 to 95 RON E10 results in a 10% increase in PMI, while an increase from 87 [R + M]/2 E10 to 98 RON E10 results in a 30% increase.
Shi, Yu, Cortes-Morales, Angel, Taylor, Bradley
Investigation of Combustion Knock Distribution in a Boosted Methane-Gasoline Blended Fueled SI Engine2018-01-02154/3/2018
The characteristics of combustion knock metrics over a number of engine cycles can be an essential reference for knock detection and control in internal combustion engines. In a Spark-Ignition (SI) engine, the stochastic nature of combustion knock has been shown to follow a log-normal distribution. However, this has been derived from experiments done with gasoline only and applicability of log-normal distribution to dual-fuel combustion knock has not been explored. To evaluate the effectiveness and accuracy of log-normal distributed knock model for methane-gasoline blended fuel, a sweep of methane-gasoline blend ratio was conducted at two different engine speeds. Experimental investigation was conducted on a single cylinder prototype SI engine equipped with two fuel systems: a direct injection (DI) system for gasoline and a port fuel injection (PFI) system for methane. The experiments were conducted at 1500 rpm and 2000 rpm, 12.0 bar net indicated mean effective pressure wherein the engine was boosted using compressed air. E10 gasoline and methane were used in this study. The results from blending two fuels show that the log-normal distribution provides a good fit to the measured distribution and captures the knock characteristics. The independency of log-normal distribution to the knock distribution at different spark timings was examined. The distribution parameters (log normal mean (μ) and standard deviation (σ)) show a linear correlation with the spark timing from knock borderline (BD) to 1.75° crank angle retarded. A μ and σ fit based log-normal (calculation-based log-normal) distribution model was proposed. The coefficients of multiple determination (CoMD) for the calculation-based log-normal model are all above 0.8 over the tested conditions. The validation of calculation-based log-normal was also conducted for all blending ratios and speeds.
Yang, Zhuyong, Rao, Sandesh, Wang, Yanyu, Harsulkar, Jaideep, Ansari, Ehsan, Miganakallu Narasimhamurthy, Niranjan, Dice, Paul, Naber, Jeffrey, Lonari, Yashodeep, Szwaja, Stanislaw
Tier 2 Test Fuel Impact to Tier 3 Aftertreatment Systems and Calibration Countermeasures2018-01-09414/3/2018
During the course of emissions and fuel economy (FE) testing, vehicles that are calibrated to meet Tier 3 emissions requirements currently must demonstrate compliance on Tier 3 E10 fuel while maintaining emissions capability with Tier 2 E0 fuel used for FE label determination. Tier 3 emissions regulations prescribe lower sulfur E10 gasoline blends for the U.S. market. Tier 3 emissions test fuels specified by EPA are required to contain 9.54 volume % ethanol and 8-11 ppm sulfur content. EPA Tier 2 E0 test fuel has no ethanol and has nominal 30 ppm sulfur content. Under Tier 3 rules, Tier 2 E0 test fuel is still used to determine FE. Tier 3 calibrations can have difficulty meeting low Tier 3 emissions targets while testing with Tier 2 E0 fuel. Research has revealed that the primary cause of the high emissions is deactivation of the aftertreatment system due to sulfur accumulation on the catalysts. The emissions drive cycles used in the test sequence play a significant role in catalyst deactivation. It is possible to desulfur the catalyst by employing an aggressive drive cycle to sustain catalyst temperatures above 650°C (1202°F). Drive cycles that produce the higher sustained catalyst temperatures are not found in the miles per gallon (MPG) method FE test sequence. Therefore, the aftertreatment system and calibration must be robust to sulfur accumulation during less aggressive drive cycles. A number of control tuning strategies were tested, and their robustness to sulfur accumulation on the catalysts was determined.
White, Eugene D., Anderson, Bruce, Ranspach, Paul
Influence of Considering Non-Ideal Thermodynamics on Droplet Evaporation and Spray Formation (for Gasoline Direct Injection Engine Conditions) Using VSB2 Spray Model2018-01-01814/3/2018
This work utilizes previously developed VSB2 (VSB2 Stochastic Blob and Bubble) multicomponent fuel spray model to study significance of using non-ideal thermodynamics for droplet evaporation under direct injection engine like operating conditions. Non-ideal thermodynamics is used to account for vapor-liquid equilibrium arising from evaporation of multicomponent fuel droplets. In specific, the evaporation of ethanol/iso-octane blend is studied in this work. Two compositions of the blend are tested, E-10 and E-85 respectively (the number denotes percentage of ethanol in blend). The VSB2 spray model is implemented into OpenFoam CFD code which is used to study evaporation of the blend in constant volume combustion vessel. Liquid and vapor penetration lengths for the E-10 case are calculated and compared with the experiment. The simulation results show reasonable agreement with the experiment. Simulation is performed with two methods- ideal and non-ideal thermodynamics respectively. For liquid penetration, the two methods show a small but evident difference. For vapor penetration, there is no significant difference. Radial fuel vapor mass fraction distribution (for both components) is obtained from simulation and compared for E-10 and E-85 cases. It is seen that for E-85 case, the difference in predictions between ideal and non-ideal thermodynamics case is significantly higher than that of E10 case. It is therefore inferred that ideal thermodynamics is not sufficient to predict vapor liquid equilibrium, especially for higher ethanol content in the blend.
Pandian Muthuramalingam, Vignesh, Karlsson, Anders
Influence of Ethanol Blends on Low Speed Pre-Ignition in Turbocharged, Direct-Injection Gasoline Engines2017-01-06873/28/2017
Modern combustion engines must meet increasingly higher requirements concerning emission standards, fuel economy, performance characteristics and comfort. Especially fuel consumption and the related CO2 emissions were moved into public focus within the last years. One possibility to meet those requirements is downsizing. Engine downsizing is intended to achieve a reduction of fuel consumption through measures that allow reducing displacement while simultaneously keeping or increasing power and torque output. However, to reach that goal, downsized engines need high brake mean effective pressure levels which are well in excess of 20bar. When targeting these high output levels at low engine speeds, undesired combustion events with high cylinder peak pressures can occur that can severely damage the engine. These phenomena, typically called low speed pre-ignition (LSPI), set currently an undesired limit to downsizing. This study analyzes the influence of ethanol fuel content on low speed pre-ignition events in a direct-injection turbo charged gasoline engine with a homogeneous (λ = 1) common rail high pressure injection system, side mounted multi-hole injectors and dual variable valve timing. All experiments were conducted on a steady state engine test bench with intake air, coolant, oil and fuel conditioning to be able to separate fuel effects from boundary condition influences. In addition, the engine was equipped with a prototype engine controller that allows to negate the influence of control algorithms on combustion. Four ethanol fuels containing different levels of ethanol were blended using the same base fuel and denatured ethanol. The investigated blends included E10, E20, E30 and E50 fuels. Subsequently, test runs were performed to understand the impact of different ethanol blends on occurrence, number and pressure characteristics of LSPI.
Haenel, Patrick, Kleeberg, Henning, de Bruijn, Rob, Tomazic, Dean
Comparison of Direct-Injection Spray Development of E10 Gasoline to a Single and Multi-Component E10 Gasoline Surrogate2017-01-08333/28/2017
Optical and laser diagnostics enable in-depth spray characterization in regards to macroscopic spray characteristics and in-situ fuel mixture quality information, which are needed in understanding the spray injection process and for spray model development, validation and calibration. Use of fuel surrogates in spray researches is beneficial in controlling fuel parameters, developing spray and combustion kinetic models, and performing laser diagnostics with known fluorescence characteristics. This study quantifies and evaluates the macroscopic spray characteristics of a single and multi-component surrogate in comparison to a gasoline with 10% ethanol under gasoline direct injection (GDI) engine conditions. In addition, the effect of fuel tracers on spray evolution and vaporization is also investigated. Both diethyl-methyl-amine/fluorobenzene as a laser-induced exciplex (LIEF) fluorescence tracer pair and 3-pentanone as a laser-induced fluorescence (LIF) tracer are examined. The spray is issued from a seven-hole production GDI injector and investigated in an optically-accessible spray and combustion vessel. Optical diagnostics include shadowgraph and Mie scattering, and the images are analyzed to reveal the characteristic spray penetration curves and the vaporization process of different fuels. Results reveal the ability of fuel surrogates in representing the target fuel and the effect of the tracer’s addition to the surrogate. While many past spray characterization works using laser diagnostics in which fuel surrogates and tracers were used assumed the spray characteristics of the surrogate/tracer mixture were similar to those of the real fuel, the assumption is fully addressed in this work, which is part of a study in which in-situ characterization of the local equivalence ratio is performed based upon the results from this work.
Tang, Meng, Zhang, Jiongxun, Zhu, Xiucheng, Yeakle, Kyle, Schmidt, Henry, Lee, Seong-Young, Naber, Jeffrey, Squibb, Cody
Effect of Ethanol Blended Fuel on Fuel Injected Two Wheeler Vehicular Mass Emissions2016-32-007511/8/2016
The effect of ethanol blended gasoline fuels on Vehicular mass emissions was investigated on a spark ignited single cylinder closed loop fuel injected vehicle complying Euro III emission norms. Fuels blended with 10(E10) & 20(E10) percentage by volume of ethanol were taken up to study their effect on vehicular mass emissions on World Harmonized Motorcycle Test Cycle (WMTC) without any modification to the vehicle. The cycle is a simulation of real world driving conditions. In WMTC Cycle, maximum CO emissions were obtained with E10 fuel which showed an increase of 13%. THC emissions decreased by 10% and NOx emissions remained the same when the ethanol blend increases. Fuel economy decreases by 5% with use of E20 on the cycle.
Setlur, Srikanth, Vemuri, Satish, Subramoniam, Chithambaram, Sharma, Rahul
Two-Stroke Engine Cleanliness via a Fuel Additive2016-32-004811/8/2016
Two-stroke engine keep-clean data is presented to demonstrate the deposit removal capabilities of a premium fuel additive. In this testing, the fuel additive was added as a top-treatment to a 50:1 blended fuel-oil mixture. Engine testing was conducted on an EchoTM SRM-265 (25.4 cc) string trimmer run under a standardized test cycle. Test measurements included piston deposits, ring deposits, and exhaust port blockage. In addition, a more complete data set was analyzed and several variables were investigated including: different base gasoline fuels, ethanol level (E0 and E10), additive dose (none, low, and high), and fuel stabilizer dose (none and high). Post-test inspection of engine parts using fuel additives showed a high level of clean surfaces, which maintained the engine at its original performance.
Parker, Garrett, Bartley, Stuart, Nicholls, Michael
Effect of Ethanol Blended Fuel on Two Wheeler Tail Pipe Mass Emissions2016-32-007611/8/2016
The effect of ethanol blended gasoline fuels on vehicle emissions was investigated in a spark ignited single cylinder carbureted vehicle meeting Bharat Stage III (BS III) emission norms. The effect of fuel blended with 10(E10) & 20(E20) percentage by volume of ethanol; was studied on vehicular mass emissions on World Harmonized Motorcycle Test Cycle (WMTC) as well as on Indian drive cycle (IDC) without any modifications on the vehicle. These cycles are simulation of real world driving conditions. The addition of ethanol to gasoline fuel enhances the octane number of the blended fuels and increases leaning effect. It has been observed on IDC that addition of ethanol reduces CO up to 41%, THC emissions decreases by 9% and NOx reduces up to 12%. In WMTC Cycle, the CO reduces up to 32%, THC emission increases by 30%. NOx emissions on WMTC cycle decrease with the use of E10 by 6% while increase with the use of E20 by 7%. The vehicles comply with BS III Emission norms in all the fuel blends. The blended fuels decrease fuel economy by 6∼8% on these cycles owing to their lower calorific value.
Sharma, Rahul, Setlur, Srikanth, Vemuri, Satish, Subramoniam, Chithambaram
Boosted Premixed-LTGC / HCCI Combustion of EHN-doped Gasoline for Engine Speeds Up to 2400 rpm2016-01-229510/17/2016
Previous work has shown that conventional diesel ignition improvers, 2-ethylhexyl nitrate (EHN) and di-tert-butyl peroxide (DTBP), can be used to enhance the autoignition of a regular-grade E10 gasoline in a well premixed low-temperature gasoline combustion (LTGC) engine, hereafter termed an HCCI engine, at naturally aspirated and moderately boosted conditions (up to 180 kPa absolute) with a constant engine speed of 1200 rpm and a 14:1 compression ratio. In the current work the effect of EHN on boosted HCCI combustion is further investigated with a higher compression ratio (16:1) piston and over a range of engine speeds (up to 2400 rpm). The results show that the higher compression ratio and engine speeds can make the combustion of a regular-grade E10 gasoline somewhat less stable. The addition of EHN improves the combustion stability by allowing combustion phasing to be more advanced for the same ringing intensity. The high-load limits of both the straight (unadditized) and additized fuels are determined, and the additized fuel is found to achieve a higher maximum load at all engine speeds and intake pressures tested, if it is not limited by lack of oxygen. The results reveal that the higher loads with EHN are the result of either reduced intake temperature requirements at naturally aspirated conditions or a reduction in heat release rate at higher intake pressures. Such effects are also found to increase the thermal efficiency, and a maximum indicated thermal efficiency of 50.1% is found for 0.15% EHN additized fuel at 1800 rpm and 180 kPa intake pressure. Similar to previous studies, the nitrogen in EHN increases NOx emissions, but they remain well below US-2010 standards. Higher engine speeds are found to have slightly lower NOx emissions for additized fuel at intake boosted conditions.
Ji, Chunsheng, Dec, John, Dernotte, Jeremie, Cannella, William
Microscopic and Macroscopic Spray Characteristics of GDI Injector Using Gasohol Fuels at Various Injection Pressures2016-01-08684/5/2016
The development of advanced gasoline direct injection (GDI) injector requires in-depth investigations of macroscopic and microscopic spray characteristics. Over the years, GDI injectors have undergone exponential improvement to be able to deliver fuel at high injection pressure. High fuel injection pressure (FIP) leads to superior fuel atomization, and consequently superior fuel-air mixing. Present investigations aim to improve our fundamental knowledge of the furl-air mixture preparation mechanisms of different test fuels. Experiments were conducted to study spray breakup of GDI injector. This study focuses on the spray investigations using Phase Doppler Interferometry (PDI) for the measurement of various spray related studies such as determination of arithmetic mean diameter (AMD), sauter mean diameter (SMD) and spray droplet velocity distributions. Gasohol mixtures (methanol and ethanol blended with gasoline) have been used as test fuels to investigate microscopic and macroscopic spray characteristics of these fuels injected from the GDI injector. The investigations were carried out at five different FIPs (40, 80, 120, 160, 200 bar). Macroscopic spray visualization was done using a high speed CCD camera at varying FIPs. It was found that spray penetration length increased with increasing FIP. Spray droplet size distribution decreased and spray droplets velocity distribution increased with increasing FIP. These results predicted behavior of GDI injector for mixture preparation at various FIPs for these two gasohols vis-à-vis baseline gasoline.
Sharma, Nikhil, Agarwal, Avinash Kumar
Analysis of EPAct Emission Data Using T70 as an Additional Predictor of PM Emissions from Tier 2 Gasoline Vehicles2016-01-09964/5/2016
In 2008-2009, EPA and DOE tested fifteen 2008 model year Tier 2 vehicles on 27 fuels. The fuels were match-blended to specific fuel parameter targets. The fuel parameter targets were pre-selected to represent the range of fuel properties from fuel survey data from the Alliance of Automobile Manufacturers for 2006. EPA's analysis of the EPAct data showed that higher aromatics, ethanol, and T90 increase particulate matter (PM) emissions. EPA focused their analysis only on the targeted fuel properties and their impacts on emissions, namely RVP, T50, T90, aromatics, and ethanol. However, in the process of fuel blending, at least one non-targeted fuel property, the T70 distillation parameter, significantly exceeded 2006 Alliance survey parameters for two of the E10 test fuels. These two test fuels had very high PM emissions. In this study, we examine the impacts of adding T70 as an explanatory variable to the analysis of fuel effects on PM. We then compare an emissions model using just the EPA variables to our new emissions model using T70. Results indicate that for the EPAct test program, the T70 distillation parameter is a better predictor of cold start PM emissions than the other distillation parameters, and a cold start emissions model that includes T70 does not include an ethanol term for cold start emissions. Further results indicate that if T70 is added to the Bag 1 EPAct model and used in EPA’s MOVES2014 emission inventory model, increased ethanol levels beyond E10 are predicted to reduce PM from on-road motor vehicles in the U.S.
Darlington, Thomas L., Kahlbaum, Dennis, Van Hulzen, Shon, Furey, Robert L.
Compatibility Assessment of Plastic Infrastructure Materials with Test Fuels Representing E10 and iBu162015-01-08944/14/2015
The compatibility of plastic materials used in fuel storage and dispensing applications was determined for a test fuel representing gasoline blended with 10% ethanol. Prior investigations were performed on gasoline fuels containing 25, 50 and 85% ethanol, but the knowledge gap existing from 0 to 25% ethanol precluded accurate compatibility assessment of low level blends, especially for the current E10 fuel (gasoline containing 10% ethanol) used in most filling stations, and the recently accepted E15 fuel blend (gasoline blended with up to15% ethanol). For the majority of the plastic materials evaluated in this study, the wet volume swell (which is the parameter most commonly used to assess compatibility) was higher for fuels containing 25% ethanol, while the volume swell accompanying E10 was much lower. However, several materials, such as polyvinylidene fluoride (PVDF), fiberglass resins, and the polyethylene terephthalate co-polymer (PETG) exhibited similar volume expansions with both 10 and 25% ethanol. In the second part of this study, the compatibility performance of the infrastructure plastics in the E10 test fuel was compared to a test fuel containing 16% isobutanol (which has the same oxygen level as E10). The measured property changes (volume and hardness) in these two fuels were similar for the majority of the plastics tested. However, Nylon 6, Nylon 6,6, and the vinyl ester fiberglass resin showed much better compatibility with a 16% isobutanol blend than with a blend containing 10% ethanol.
Kass, Michael D., Janke, Chris, Theiss, Timothy, Baustian, James, Wolf, Leslie, Koch, Wolf
Effects of Gasoline Reactivity and Ethanol Content on Boosted, Premixed and Partially Stratified Low-Temperature Gasoline Combustion (LTGC)2015-01-08134/14/2015
Low-temperature gasoline combustion (LTGC), based on the compression ignition of a premixed or partially premixed dilute charge, can provide thermal efficiencies (TE) and maximum loads comparable to those of turbo-charged diesel engines, and ultra-low NOx and particulate emissions. Intake boosting is key to achieving high loads with dilute combustion, and it also enhances the fuel's autoignition reactivity, reducing the required intake heating or hot residuals. These effects have the advantages of increasing TE and charge density, allowing greater timing retard with good stability, and making the fuel ϕ- sensitive so that partial fuel stratification (PFS) can be applied for higher loads and further TE improvements. However, at high boost the autoignition reactivity enhancement can become excessive, and substantial amounts of EGR are required to prevent overly advanced combustion. Accordingly, an experimental investigation has been conducted to determine how the tradeoff between the effects of intake boost varies with fuel-type and its impact on load range and TE. Five fuels are investigated: a conventional AKI=87 petroleum-based gasoline (E0), and blends of 10 and 20% ethanol with this gasoline to reduce its reactivity enhancement with boost (E10 and E20). A second zero-ethanol gasoline with AKI=93 (matching that of E20) was also investigated (CF-E0), and some neat ethanol data are also reported. Results show that ethanol content has little effect on LTGC autoignition reactivity for naturally aspirated operation, but it produces a large effect for boosted operation, with the reactivity enhancement with boost being reduced by an amount that correlates with ethanol content. In contrast, CFE0 showed a reactivity enhancement with boost similar to E0. Related to this autoignition enhancement, the effect of fuel-type on the increase in ITHR with boost was also investigated since it correlates with the ability to retard CA50 with good stability for higher loads without knock and to apply PFS effectively. The study showed that by adding ethanol, less EGR is required with boost, leaving more oxygen available for combustion. As a result, the high-load limit could be increased from 16.3 to 18.1 to 20.0 bar IMEPg for E0, E10, and E20, respectively, and to 17.7 bar for the high-AKI gasoline. TE vs. load curves for the various fuels at typical boosted conditions are also presented and discussed. At boosted conditions, PFS was found to be very effective for increasing the TE, with the peak TE increasing from 47.8% for premixed fueling to 48.4% with PFS, and TE improvements up to 2.8 %-units were achieved at higher loads.
Dec, John E., Yang, Yi, Dernotte, Jeremie, Ji, Chunsheng
The Impact of Isobutanol and Ethanol on Gasoline Fuel Properties and Black Carbon Emissions from Two Light-Duty Gasoline Vehicles2015-01-10764/14/2015
This study reported black carbon (BC) mass and solid particle number emissions from a gasoline direct injection (GDI) vehicle and a port fuel injection (PFI) vehicle on splash blended E10 and iB16 fuels over the FTP-75 and US06 drive cycles at standard and cold ambient temperatures. For the FTP-75 drive cycle, the GDI vehicle had lower solid particle number and BC mass emissions from E10 (5.1×1012 particles/mile; 4.2 mg/mile) and iB16 (5.2×1012 particles/mile; 3.9 mg/mile) compared to E0 (7.2×1012 particles/mile; 7.0 mg/mi). Most of the reductions were attributed to the statistically significant reductions during the phases 1 and 2 of the FTP-75 drive cycle. iB16 was also observed to have statistically significant reduction on BC emissions when compared to E0 at cold ambient temperature but E10 did not show such BC reduction. For the PFI vehicle, most of the solid particle number and BC mass emissions were emitted primarily during phase 1 of the FTP-75 drive cycle. In general, solid particle number and BC mass emissions from the warmed PFI vehicle were low (0.5-1.3×1012 particles/mile; 0.2-0.8 mg/mi) and most of the fuel effects were not statistically significant. However, iB16 fuel was consistently observed to increase both solid particle number and BC mass emissions during phase 1 of the FTP-75 drive cycle while no statistically different solid particle number and BC mass emissions were observed for the E10 fuel.
Chan, Tak W.
Gaseous and Particulate Emissions Using Isobutanol-Extended Fuel in Recreational Marine Two-Stroke and Four-Stroke Engines2014-32-008711/11/2014
Biologically derived isobutanol, a four carbon alcohol, has an energy density closer to that of gasoline and has potential to increase biofuel quantities beyond the current ethanol blend wall. When blended at 16 vol% (iB16), it has identical energy and oxygen content of 10 vol% ethanol (E10). Engine dynamometer emissions tests were conducted on two open-loop electronic fuel-injected marine outboard engines of both two-stroke and four-stroke designs using indolene certification fuel (non-oxygenated), iB16 and E10 fuels. Total particulate emissions were quantified using Sohxlet extraction to determine the amount of elemental and organic carbon. Data indicates a reduction in overall total particulate matter relative to indolene certification fuel with similar trends between iB16 and E10. Gaseous and PM emissions suggest that iB16, relative to E10, could be promising for increasing the use of renewable fuels in recreational marine engines and fuel systems.
Wasil, Jeff R., Wallner, Thomas
Evaluating Particulate Emissions from a Flexible Fuel Vehicle with Direct Injection when Operated on Ethanol and Iso-butanol Blends2014-01-276810/13/2014
The relationship between ethanol and iso-butanol fuel concentrations and vehicle particulate matter emissions was investigated. This study utilized a gasoline direct injection (GDI) flexible fuel vehicle (FFV) with wall-guided fueling system tested with four fuels, including E10, E51, E83, and an iso-butanol blend at a proportion of 55% by volume. Emission measurements were conducted over the Federal Test Procedure (FTP) driving cycle on a chassis dynamometer with an emphasis on the physical and chemical characterization of particulate matter (PM) emissions. The results indicated that the addition of higher ethanol blends and the iso-butanol blend resulted in large reductions in PM mass, soot, and total and solid particle number emissions. PM emissions for the baseline E10 fuel were characterized by a higher fraction of elemental carbon (EC), whereas the PM emissions for the higher ethanol blends were more organic carbon (OC) in nature. The higher ethanol blends and the iso-butanol blend showed lower concentrations of accumulation mode particles and size distributions shifted to smaller particle sizes compared to E10. In addition, the majority of trace elements and metals showed clear reductions with increasing alcohol content into gasoline.
Karavalakis, George, Short, Daniel, Chen, Vincent, Espinoza, Carlos, Berte, Tyler, Durbin, Thomas, Asa-Awuku, Akua, Jung, Heejung, Ntziachristos, Leonidas, Amanatidis, Stavros, Bergmann, Alexander
The Influence of Ethanol Blending in Diesel fuel on the Spray and Spray Combustion Characteristics2014-01-275510/13/2014
The influence of ethanol blending in Diesel fuel on the spray and spray combustion characteristics was investigated by performing experiments in an optically accessible high-pressure / high-temperature spray chamber under non-evaporating, evaporating and combusting conditions. Three fuels were investigated: (1) Diesel - a European Diesel based on the EN590 standard; (2) E10 - a blend of Diesel containing 10% ethanol and 2% emulsion additive; and (3) E20 - a blend of Diesel containing 20% ethanol and 2% emulsion additive. A constant gas density of 24.3 kg/m3 was maintained under non-evaporating (30 °C, 21.1 bar), evaporating (350 °C, 43.4 bar), low combustion temperature (550 °C, 57.3 bar) and high combustion temperature (600 °C, 60 bar) conditions. A single-hole injector with a nozzle diameter of 0.14 mm was used and injection pressure was held constant at 1350 bar. Various optical methods were used to characterize the non-combusting and combusting sprays. Despite the differences in the fuels' compositions, they did not differ significantly with respect to their liquid phase spray penetrations or cone angles under non-evaporating or evaporating conditions. However, under combusting conditions, reducing the ambient temperature increased the ignition delay and delayed the onset of soot formation for all fuels. Under equivalent combustion conditions, E10 and E20 had longer ignition and soot formation delays than Diesel. As the ethanol content of the fuel was increased from 0% to 20%, the lift-off length increased and the detectable soot luminescence decreased.
Du, Chengjun, Andersson, Mats, Andersson, Sven
Study of High-Compression-Ratio Engine Combined with an Ethanol-Gasoline Fuel Separation System2014-01-261410/13/2014
Bio-ethanol is used in many areas of the world as ethanol blended gasoline at low concentrations such as “E10 gasoline”. In this study, a method was examined to effectively use this small amount of ethanol within ethanol blended gasoline to improve thermal efficiency and high-load performance in a high-compression-ratio engine. Ethanol blended gasoline was separated into high-concentration ethanol fuel and gasoline using a fuel separation system employing a membrane. High-ethanol-concentration fuel was selectively used at high-load conditions to suppress knocking. In this system, a method to decrease ethanol consumption is necessary to cover the wide range of engine operation. Lower ethanol consumption could be achieved by Miller-cycle operation because decrease of the effective compression ratio suppresses knocking. However, high-load operation was limited due to the decrease in intake air volume with Miller-cycle operation. To solve this problem, conventional Otto-cycle operation is used in high-load conditions, utilizing large quantities of ethanol injection to avoid knocking. The two different cycles were smoothly switched with innovative application of a variable valve timing system. In summary, optimum control of the variable valve timing (i.e. effective compression ratio) and ethanol injection fraction allows efficient use of the limited amount of ethanol available. As a result, higher-load and higher thermal efficiency operation was achieved due to the increased compression ratio. Additionally, it is possible to complete the US-06 driving cycle using the above-mentioned system, assuming a realistic engine displacement has been selected according to the vehicle weight.
Kuzuoka, Kohei, Kurotani, Tadashi, Chishima, Hiroshi, Kudo, Hirotsugu
Regulated Emissions, Unregulated Emissions and Fuel Consumption of Two Vehicles Tested on Various Petrol-Ethanol Blends2014-01-282410/13/2014
Ethanol has a long history as an automotive fuel and is currently used in various blends and formats as a fuel for spark ignition engines in many areas of the world. The addition of ethanol to petrol has been shown to reduce certain types of emissions, but increase others. This paper presents the results of a detailed experimental program carried out under standard laboratory conditions to determine the influence of different quantities of petrol-ethanol blends (E5, E10, E25, E50 and E85) on the emission of regulated and unregulated gaseous pollutants and particulate matter. The ethanol-petrol blends were laboratory tested in two European passenger cars on a chassis dynamometer over the New European Driving Cycle, using a constant volume sampler and analyzers for quantification of both regulated and unregulated emissions. The emissions results revealed non-linear or insignificant changes in response to the addition of ethanol to the base fuel regarding certain parameters; and linear responses regarding others. Changes in regulated emissions were generally limited for blends up to E25; E50 and E85 caused greater changes in some cases. Particulate matter emissions followed a non-linear trend in response to blend ethanol content, with the highest emissions observed for the E10 blend. Unregulated emissions showed changes associated with the use of ethanol as a fuel component, including increases in concentrations of ethanol itself in the exhaust gas. Volumetric fuel consumption increased unambiguously as ethanol content increased, with blend energy content being an excellent predictor of fuel consumption for blends as high as E50.
Bielaczyc, Piotr, Szczotka, Andrzej, Woodburn, Joseph
Vehicle Evaporative Emissions Characterization by Chromatographic Techniques Applied to Different Gasoline-Ethanol Blends2014-01-15744/1/2014
Currently, regulations on vehicle evaporative emissions only focus on the sum of Total Hydrocarbons (THC) without taking into account either the detailed hydrocarbon composition nor other chemicals besides hydrocarbons emitted from gasoline evaporation. As a consequence, this composition, also known as speciation, is not always noted and is even more unknown when biofuels such as ethanol are introduced in the market. Furthermore, these regulations do not differentiate the source of these emissions in the vehicle. The programme described in this paper is designed to investigate the influence of the addition of ethanol to gasoline on evaporative emissions. It has tried to go one step ahead of these directives obtaining more detailed characterization of these evaporative emissions. The programme has enabled a list of compounds (methanol, ethanol, aldehydes, ketones and hydrocarbons) to be determined in evaporative emissions among different ethanol-gasoline fuels (E0, E5-S, E10 and E85), applied to Euro 4 and Flexifuel vehicles by three chromatographic methods based on California Air Resources Board (CARB). Additionally, permeation from evaporation emissions has been determined separately. This document provides valuable information about the speciation of evaporative emissions and several conclusions have been drawn.
Paz, Susanna, Delgado, Rosa, Riba, David
Onboard Gasoline Separation for Improved Vehicle Efficiency2014-01-12004/1/2014
ExxonMobil, Corning and Toyota have collaborated on an Onboard Separation System (OBS) to improve gasoline engine efficiency and performance. OBS is a membrane based process that separates gasoline into higher and lower octane fractions, allowing optimal use of fuel components based on engine requirements. The novel polymer-ceramic composite monolith membrane has been demonstrated to be stable to E10 gasoline, while typically providing 20% yield of ∼100 RON product when using RUL 92 RON gasoline. The OBS system makes use of wasted exhaust energy to effect the fuel separation and provides a simple and reliable means for managing the separated fuels that has been demonstrated using several generations of dual fuel test vehicles. Potential applications include downsizing to increase fuel economy by ∼10% while maintaining performance, and with turbocharging to improve knock resistance.
Partridge, Randall D., Weissman, Walter, Ueda, Takanori, Iwashita, Yoshihiro, Johnson, Paul, Kellogg, George
Study of Compatibility of Metals used in Fuel System of Gasoline Engine with E10 and E202013-01-288011/27/2013
Impact of higher gasoline-ethanol blends E10 and E20, on the fuel system components of gasoline vehicles must be known to ascertain the intended performance of these components throughout its service life. Study of compatibility of particular selected grades of metals, like Aluminium alloy, Brass & Stainless steel, with ethanol-gasoline blends (E10 and E20) in comparison with Commercial gasoline was conducted as per the guidelines given in SAE J1747. Three specimen of each metal were exposed (Fully immersed, half immersed & Vapour) to above fuels at 45 °C for 2016 hours. Mass loss/ gain data was recorded periodically at the end of 1st, 3rd, 6th, and 12th week and based on this data corrosion rate was calculated. Substantial tarnishing was observed in case of brass & slight colour change in case of aluminium & steel alloys. All the three distinct metals grades tested were found compatible with E10 & E20 with no significant corrosion rate at the end of the test period. The study has revealed useful information for the vehicle and component manufacturers with respect to the compatibility of the metals for their application in fuel system
Vyas, Dharmdev, Bawase, Moqtik A, Saraf, M R
Impact of Ambient Temperature on Gaseous and Particle Emissions from a Direct Injection Gasoline Vehicle and its Implications on Particle Filtration2013-01-05274/8/2013
Gaseous and particle emissions from a gasoline direct injection (GDI) and a port fuel injection (PFI) vehicle were measured at various ambient temperatures (22°C, -7°C, -18°C). These vehicles were driven over the U.S. Federal Test Procedure 75 (FTP-75) and US06 Supplemental Federal Test Procedure (US06) on Tier 2 certification gasoline (E0) and 10% by volume ethanol (E10). Emissions were analyzed to determine the impact of ambient temperature on exhaust emissions over different driving conditions. Measurements on the GDI vehicle with a gasoline particulate filter (GPF) installed were also made to evaluate the GPF particle filtration efficiency at cold ambient temperatures. The GDI vehicle was found to have better fuel economy than the PFI vehicle at all test conditions. Reduction in ambient temperature increased the fuel consumption for both vehicles, with a much larger impact on the cold-start FTP-75 drive cycle observed than for the hot-start US06 drive cycle. Colder ambient temperatures were also found to increase CO, THC, and particle emissions over the FTP-75 drive cycle, with little impact on the emissions over the US06 drive cycle. E10 was found to decrease particle number emissions from the PFI vehicle over both test cycles and all ambient temperatures. E10 almost always led to higher particle emissions from the GDI vehicle, except over the FTP-75 drive cycle at standard temperature. Limited soot regeneration in the GPF was observed at cold ambient temperatures over the FTP-75 drive cycle. However, the particle filtration efficiency of the GPF did not significantly change during cold ambient testing. On average, the mass-based GPF filtration efficiency over the FTP-75 drive cycle was observed to vary from 62% at standard temperature to 92% at -18°C. When based on particle number, the GPF filtration efficiency varied from 85% at standard temperature to 80% at -18°C. Over the US06 drive cycle, multiple spontaneous soot regenerations were observed and led to lower particle filtration efficiency. Mass-based filtration efficiency of the GPF was found to vary from 36% at standard temperature to 52% at -18°C. Number-based filtration efficiency varied from 83% at standard temperature to 60% at -18°C.
Chan, Tak W., Meloche, Eric, Kubsh, Joseph, Brezny, Rasto, Rosenblatt, Deborah, Rideout, Greg
Blend Ratio Optimization of Fuels Containing Gasoline Blendstock, Ethanol, and Higher Alcohols (C3-C6): Part I - Methodology and Scenario Definition2013-01-11444/8/2013
The U.S. Renewable Fuel Standard (RFS2) requires an increase in the use of advanced biofuels up to 36 billion gallons by 2022. Longer chain alcohols, in addition to cellulosic ethanol and synthetic biofuels, could be used to meet this demand while adhering to the RFS2 corn-based ethanol limitation. Higher carbon number alcohols can be utilized to improve the energy content, knock resistance, and/or petroleum displacement of gasoline-alcohol blends compared to traditional ethanol blends such as E10 while maintaining desired and regulated fuel properties. Part I of this paper focuses on the development of scenarios by which to compare higher alcohol fuel blends to traditional ethanol blends. It also details the implementation of fuel property prediction methods adapted from literature. Possible combinations of eight alcohols mixed with a gasoline blendstock were calculated and the properties of the theoretical fuel blends were predicted. Each scenario details an overall objective and identifies chemical and engine related properties that are crucial to meeting that objective as fuel criteria. Appropriate target values for each criterion are based on U.S. fuel industry standards, consumer expectations, engine requirements, and government legislation. The objective of the E10/E15 Alternate scenario is to identify alcohol blends with oxygen content that meet the EPA E15 waiver, have vapor pressure within ASTM standards, and energy content, knock resistance, and petroleum displacement at least equal to that of current ethanol blends. The objective of the RFS2 Fuel scenario is to identify blends that contain an ethanol-equivalent alcohol volume that meets the RFS2 requirement in addition to vapor pressure, knock resistance, and energy content criteria similar to those in the E10/E15 Alternate scenario.
Lawyer, Kristina, Ickes, Andrew, Wallner, Thomas, Ertl, David, Williamson, Rodney, Miers, Scott, Naber, Jeffrey
Blend Ratio Optimization of Fuels Containing Gasoline Blendstock, Ethanol, and Higher Alcohols (C3-C6): Part II - Blend Properties and Target Value Sensitivity2013-01-11264/8/2013
Higher carbon number alcohols offer an opportunity to meet the Renewable Fuel Standard (RFS2) and improve the energy content, petroleum displacement, and/or knock resistance of gasoline-alcohol blends from traditional ethanol blends such as E10 while maintaining desired and regulated fuel properties. Part II of this paper builds upon the alcohol selection, fuel implementation scenarios, criteria target values, and property prediction methodologies detailed in Part I. For each scenario, optimization schemes include maximizing energy content, knock resistance, or petroleum displacement. Optimum blend composition is very sensitive to energy content, knock resistance, vapor pressure, and oxygen content criteria target values. Iso-propanol is favored in both scenarios' suitable blends because of its high RON value. A range of blends of ethanol, propanol, butanol, and pentanol with a gasoline blendstock can possess energy content, knock resistance, and/or petroleum displacement that exceed current gasoline-ethanol blends while meeting oxygen content and vapor pressure regulations. Results are similar whether examining blends with total alcohol content comparable to E10/E15 or alcohol content high enough to meet RFS2 requirements. Blends of higher alcohols with BOB can meet oxygen content, vapor pressure, and/or knock resistance requirements while increasing energy content and/or petroleum displacement. For example, if higher knock resistance is desired, a blend of iso-propanol and iso-butanol with BOB meets oxygen content, vapor pressure, and energy content requirements while increasing knock resistance and petroleum displacement as compared to E10.
Lawyer, Kristina, Ickes, Andrew, Wallner, Thomas, Ertl, David, Williamson, Rodney, Miers, Scott, Naber, Jeffrey
Criteria Emissions, Particle Number Emissions, Size Distributions, and Black Carbon Measurements from PFI Gasoline Vehicles Fuelled with Different Ethanol and Butanol Blends2013-01-11474/8/2013
The introduction of biofuels is seen as a very important measure to reduce the emissions of greenhouse gases from the transport sector. Currently, ethanol is the most widely used renewable fuel for transportation in the US and with the push to use increasingly higher levels of renewable fuels, there has been an accompanying push to further increase the ethanol level in gasoline. In addition to ethanol, butanol, an alcohol which can be produced from biomass sources, has recently received more attention as an alternative to gasoline for use in spark ignition (SI) engines. For this study, two 2007 model year and one 2012 model year light-duty vehicles equipped with a three-way catalyst (TWC) were employed. For the 2007 model year vehicles, emissions and fuel economy measurements were made for E10 (reference fuel), E15, E20, and B16 fuels. The latter corresponds to a blend of gasoline and 16% of butanol, which is the equivalent of E10 in terms of oxygen content. For the 2012 passenger car, in addition to E10, E15, E20, and B16, emissions and fuel economy tests were also made for E10/B8. The alcohol mixture of E10/B8 is equivalent of E15 in terms of oxygen content. Emissions measurements were performed over the Federal Test Procedure (FTP) and the California Unified Cycle (UC) test cycles for each vehicle/fuel combination on a chassis dynamometer. Emissions included nitrogen oxides (NOx), carbon monoxide (CO), total hydrocarbons (THC), non-methane hydrocarbons (NMHC), methane (CH₄), and carbon dioxide (CO₂). Additionally, carbonyl compounds were also quantified in the exhaust for all vehicle/fuel combinations over the FTP cycle. Particle size and number were measured with a scanning mobility particle sizer (SMPS) in tandem with a condensation particle counter (CPC). The concentration of black carbon was also measured with a Multi-Angle Absorption Photometer (MAAP).
Karavalakis, George, Short, Daniel, Hajbabaei, Maryam, Vu, Diep, Villela, Mark, Russell, Robert, Durbin, Thomas, Asa-Awuku, Akua
An Overview of the Effects of Ethanol-Gasoline Blends on SI Engine Performance, Fuel Efficiency, and Emissions2013-01-16354/8/2013
This paper provides an overview of the effects of blending ethanol with gasoline for use in spark ignition engines. The overview is written from the perspective of considering a future ethanol-gasoline blend for use in vehicles that have been designed to accommodate such a fuel. Therefore discussion of the effects of ethanol-gasoline blends on older legacy vehicles is not included. As background, highlights of future emissions regulations are discussed. The effects on fuel properties of blending ethanol and gasoline are described. The substantial increase in knock resistance and full load performance associated with the addition of ethanol to gasoline is illustrated with example data. Aspects of fuel efficiency enabled by increased ethanol content are reviewed, including downsizing and downspeeding opportunities, increased compression ratio, fundamental effects associated with ethanol combustion, and reduced enrichment requirement at high speed/high load conditions. The effects of ethanol content on emissions are also reviewed, including NMOG/CO/NOX, particulate matter, toxic compounds, and off-cycle and evaporative emissions. Considering the engine and vehicle-related factors reviewed in this paper, a mid-level ethanol-gasoline blend (greater than E20 and less than E40) appears to be attractive as a future fuel. To provide high knock resistance, this fuel should be formulated using a blendstock that retains the octane of the current blendstock used for regular-grade E10 gasoline. Further work is needed to recommend a specific ethanol blend level, including analysis of fuel efficiency and CO₂ benefits for representative powertrain/vehicle applications, and of fuel production and supply considerations.
Stein, Robert A., Anderson, James E., Wallington, Timothy J.
Vehicle Exhaust Emissions Characterization by Chromatographic Techniques Applied to Different Gasoline-Ethanol Blends.2013-01-10444/8/2013
Current regulations on exhaust automotive emissions focus on certain pollutants to control vehicle emissions. Hydrocarbons, the main components of gasoline, are one of these regulated compounds; however, the regulation only refers to the sum of total hydrocarbons (THC) without taking into account the individual components. Vehicles also emit a large variety of chemical besides hydrocarbons that can become much more harmful, depending on their environmental toxicity and the amounts that are emitted to the atmosphere. In recent years, due to the emergence of alternative fuels such as bioethanol and biodiesel, the interest in these not so well characterized compounds has grown. For example, when ethanol is used in gasoline blends as a fuel for internal-combustion engine vehicles, the study of other compounds such as alcohols, aldehydes and ketones, in addition to hydrocarbons, acquires more importance. Based on SOP 101, 102-103 and 104 by California Air Resources Board (CARB), three chromatographic methods for the analysis of methanol and ethanol (HRGC-FID), aldehydes and ketones (HLPC-UV), and individual hydrocarbons (C₂-C₁₂) (thermal adsorption/desorption system-HRGC/FID-FID) have been developed. All three methods have been optimized, validated and implemented in automotive exhaust samples analysis. This has allowed us to determine regulated as well as non-regulated compounds from emissions among different ethanol-gasoline fuels (E0, E5-S, E10 and E85), applied to Euro 4 and Flexifuel vehicles.
Paz-Estivill, Susanna, Delgado-Ortiz, Rosa, Cirera-Domènech, Elisenda, Broto-Puig, Francesc
Improving Efficiency and Using E10 for Higher Loads in Boosted HCCI Engines2012-01-11074/16/2012
This study systematically investigates the effects of various engine operating parameters on the thermal efficiency of a boosted HCCI engine, and the potential of E10 to extend the high-load limit beyond that obtained with conventional gasoline. Understanding how these parameters can be adjusted and the trade-offs involved is critical for optimizing engine operation and for determining the highest efficiencies for a given engine geometry. Data were acquired in a 0.98 liter, single-cylinder HCCI research engine with a compression-ratio of 14:1, and the engine facility was configured to allow precise control over the relevant operating parameters. The study focuses on boosted operation with intake pressures (Pin) ≥ 2 bar, but some data for Pin < 2 bar are also presented. Two fuels are considered: 1) an 87-octane gasoline, and 2) E10 (10% ethanol in this same gasoline) which has a lower autoignition reactivity for boosted operation. This study considers several engine operating parameters, including: intake temperature, fueling rate, engine speed, fuel type, and the effect of various amounts of mixture stratification using three fueling methods: fully premixed, early-DI, and premixed + late-DI (termed partial fuel stratification, PFS). The effects of these operating parameters on the factors affecting thermal efficiency, such as combustion phasing (CA50), amount of EGR required, ringing intensity, combustion efficiency, γ = cp/cv, and heat transfer are also explored and discussed. The study showed that in general, thermal efficiency improves when parameters are adjusted for lower intake temperatures, less CA50 retard, and less EGR, as long as the ringing intensity is ≤ 5 MW/m2 to prevent knock, and combustion efficiency is good (i.e., ≥ about 96%). Additionally, applying a small amount of mixture stratification (using PFS or early-DI fueling) improves efficiency by allowing more CA50 advance when boost levels are sufficient for these fuels to be ϕ-sensitive. E10 gives a small increase in thermal efficiency because EGR requirements are reduced. E10 is also effective for increasing the maximum load for Pin ≥ 2.4 bar, and increasing the high-load limit to IMEPg = 18.1 bar, with no engine knock and ultra-low NOx and soot emissions, compared to IMEPg = 16.3 bar for gasoline. Overall, this study showed that the efficiencies for boosted HCCI can be increased above their already good baseline values. For our engine configuration, improvements of 3 - 5 thermal-efficiency percentage units were achieved corresponding to a reduction in fuel consumption of 7 - 11%.
Dec, John E., Yang, Yi, Dronniou, Nicolas
Octane Numbers of Ethanol-Gasoline Blends: Measurements and Novel Estimation Method from Molar Composition2012-01-12744/16/2012
Ethanol has a high octane rating and can be added to gasoline to produce high octane fuel blends. Understanding the octane increase with ethanol blending is of great fundamental and practical importance. Potential issues with fuel flow rate and fuel vaporization have led to questions of the accuracy of octane measurements for ethanol-gasoline blends with moderate to high ethanol content (e.g., E20-E85) using the Cooperative Fuel Research (CFR™) engine. The nonlinearity of octane ratings with volumetric ethanol content makes it difficult to assess the accuracy of such measurements. In the present study, Research Octane Number (RON) and Motor Octane Number (MON) were measured for a matrix of ethanol-gasoline blends spanning a wide range of ethanol content (E0, E10, E20, E30, E50, E75) in a set of gasoline blendstocks spanning a range of RON values (82, 88, 92, and 95). Octane ratings for neat ethanol, denatured ethanol, and hydrous ethanol were also measured. One set of measurements was conducted using a CFR™ engine equipped with manufacturer-supplied enhancements (GE Energy Waukesha XCP-OA™ digital octane panel) for digital knock measurement and precise control of temperatures and fuel flow. A second set of measurements was conducted at a separate laboratory with a CFR™ engine equipped with an adjustable-orifice fuel jet. Both approaches address fuel flow issues at high ethanol concentrations. A linear molar octane blending model was found to describe most of the nonlinearity in the RON and MON data, but measured values were still somewhat greater than predicted. Deviations from the linear model can be described by a term with 2nd-order dependence on ethanol content with a single scaling parameter (Pg). The parameter Pg can be estimated from the measured octane number of a 50:50 molar alcohol-gasoline blend and the octane numbers of the gasoline (ONg) and alcohol (ONa). The octane number of any ethanol-gasoline blend (ONb) with that blendstock can then be estimated (within 1 ON) from the molar fraction of the alcohol (xa) using the following expression: ONb = (1-xa)ONg + xaONa + Pg xa (1-xa)(ONa - ONg). This study supports a companion paper (SAE 2012-01-1277) in which a state-of-the-art single-cylinder engine equipped with multiple fuel injection systems was used to evaluate the knock-limited performance of the ethanol-gasoline blends described herein and to evaluate the relevance of octane ratings and heat of vaporization as predictors of this performance.
Anderson, James E., Leone, Thomas G., Shelby, Michael H., Wallington, Timothy J., Bizub, Jeffrey J., Foster, Michael, Lynskey, Michael G., Polovina, Dusan
A Study of Gasoline-Ethanol Blends Influence on Performance and Exhaust Emissions from a Light-Duty Gasoline Engine2012-01-10524/16/2012
This paper evaluates the possibility of using bioethanol blends (mixtures of gasoline fuel and ethanol derived from biomass) of varying strengths in an unmodified, small-displacement European Euro 5 light-duty gasoline vehicle. The influence of different proportions of bioethanol in the fuel blend (E5, E10, E25, E50 and E85) on the emission of gaseous pollutants, such as: carbon monoxide, hydrocarbons, oxides of nitrogen and carbon dioxide was tested at normal (22°C) and low (-7°C) ambient temperatures for a light-duty vehicle during the NEDC cycle on a chassis dynamometer. Engine performance metrics were also tested. All test results are presented in comparison to standard European gasoline (E5). Tailpipe emission data presented here suggest that modest improvements in air quality could result from usage of low-to-mid ethanol blends in the vehicle tested. In general, blends up to and including E50 were relatively unproblematic; emissions of regulated compounds and CO₂ were in some cases substantially lower for ethanol blends higher than E5 (standard European gasoline). This finding has potentially significant implications for air quality scenarios regarding potential greater usage of ethanol blends. However, the usage of two ambient temperatures in this study confirmed previous findings that such emissions reductions are in some cases strongly temperature dependent, and further testing is required in this area. Overall, no single blend emerged as a clear best or worst performer at either test temperature. Although maximum engine power and torque values for all blends were very similar, it was observed that for the E5 blend, engine power and torque were the highest, whereas for the blend E10 they were the lowest. The maximum power for the blend E10 was some 2% lower (significant at the 95% confidence level) in comparison to results obtained for the E5 blend. This paper represents a continuation of related research previously described elsewhere.
Bielaczyc, Piotr, Szczotka, Andrzej, Woodburn, Joseph
Impact of Ethanol Fuels on Regulated Tailpipe Emissions2012-01-08724/16/2012
Flexible fuel vehicle production has been steadily increasing in the US over the past fifteen years. Ethanol is considered a renewable fuel additive to gasoline which helps the US efforts in minimizing the dependency on foreign oil. As a result, it is becoming very hard to find pure gasoline which does not contain some ethanol content at the pump in the US. The fuel currently available at the pump contains close to 10% ethanol. The fuel and evaporative systems components and materials on newer flexible fuel vehicles are being designed to be tolerant of the 10% ethanol content. There is a strong desire from ethanol producers to increase the ethanol content up to a 20% level. This is still being debated by the Environmental Protection Agency and a final decision has not been made yet but will be announced by the upcoming Tier 3 Notice of Public Rule Making (NPRM) in December of 2011. Early signs from EPA are indicating the E15 would be the official certification fuel with the upcoming Tier 3 NPRM. The California Air Resources Board (CARB) proposed in the LEV III NPRM to use E10 as the official fuel for all required certification testing. Many studies are being done investigating the impact of the 20% ethanol fuel blend on the different components in the vehicle especially on the evaporative systems. This study focuses on the effect of ethanol content on tailpipe emissions including carbonyls. The effect of ethanol addition to gasoline fuels on regulated tailpipe emissions is investigated under different ethanol content and different ambient temperatures. In addition to THC, CO, NOx, CH₄ and CO₂ tailpipe emissions, the analysis includes carbonyl measurement with formaldehydes, acetaldehydes, and other 11 carbonyl species. Testing was conducted on a 3.3 L Chrysler Town & Country vehicle at different ambient temperatures (20°F or -7°C, 50°F or 10°C and 75°F or 24°C) with indolene certification fuels containing 0, 10%, 20% and 85% ethanol. The effect of varying the Reid vapor pressure (RVP) on tailpipe emissions with E85 fuels is also discussed.
Yassine, Mahmoud K., La Pan, Morgan
Light-Duty Reactivity Controlled Compression Ignition Combustion Using a Cetane Improver2012-01-11104/16/2012
Premixed compression ignition (PCI) strategies offer the potential for simultaneously low NOx and soot emissions and diesel-like efficiency. However, these strategies are generally confined to low loads due to difficulties controlling the combustion phasing and heat release rate. Recent experiments have demonstrated that dual-fuel reactivity-controlled compression ignition (RCCI) combustion can improve PCI combustion control and expand the PCI load range. Previous studies have explored RCCI operation using port-fuel injection (PFI) of gasoline and direct-injection (DI) of diesel fuel. In this study, experiments are performed using a light-duty, single-cylinder research engine to investigate RCCI combustion using a single fuel with the addition of a cetane improver 2-ethylhexyl nitrate (EHN). The fuel delivery strategy consists of port-fuel injection of E10 (i.e., 10% ethanol in gasoline) and direct-injection of E10 mixed with 3% EHN. The results using the E10+EHN strategy are compared to an E10+diesel dual-fuel strategy. It was found that the additized E10 blend performed similar to diesel fuel and was capable of achieving controlled PCI operation over a range of conditions. In contrast to previous low-temperature combustion studies using EHN, the present work shows that, since the EHN quantity is very low (~0.3% of the total fuel), the nitrogen in the fuel only results in a small increase in NOx emissions. Although NOx emissions of E10-EHN RCCI are slightly higher than E10-diesel RCCI, NOx levels are below 1 g/kW-hr over a range of loads. Similar to previous light-duty dual-fuel RCCI operation, the single-fuel E10-EHN RCCI strategy demonstrated a peak-indicated efficiency of near 50% at a mid-load (9 bar gross IMEP) operating condition.
Kaddatz, John, Andrie, Michael, Reitz, Rolf D., Kokjohn, Sage
Experimental Investigation on Particle Number and Size Distribution of a Common Rail Diesel Engine Fueling with Alternative Blended Diesel Fuels2011-01-06204/12/2011
An EURO 3 certified common rail diesel engine was fueled with pure petroleum diesel (EURO 4 standard) and three different alternative blended diesel fuels, 10% biodiesel blended diesel (B10), 10% gas to liquid blended diesel (G10) and 10% water emulsified diesel (E10). Tests were performed at different engine speeds and load states. Particle number concentration and size distribution data were obtained from an engine exhaust particle sizer (EEPS). Over all the working conditions, total particle and nucleation mode particle number concentration among these fuels from high to low were in this order: B10, E10, pure diesel and G10. Proportions for nucleation mode particle over all the operating states in that order were 89%, 82%, 59% and 66%. Particle size distributions of B10 and E10 presented bimodal logarithmic distributions with outstanding nucleation mode peaks at all working conditions. G10 and pure diesel presented unimodal logarithmic distributions at full load conditions, and presented bimodal logarithmic distributions with nucleation mode peaks at part load conditions. Accumulation mode particle number concentration had a common trend with smoke intensity, but nucleation mode particle data had no clear relationship to smoke intensity. The results indicate that G10 has less particle emissions than pure diesel, the increases in both total particle and nucleation mode particle emissions caused by B10 and E10 need to pay a great concern.
Yao, Di, Lou, Diming, Hu, Zhiyuan, Tan, Piqiang
The Effect of Using Ethanol-blended Gasoline on the Performance and Durability of Fuel Delivery Systems in Classic Automobiles2010-01-213510/25/2010
Currently, a majority of the ‘gasoline’ sold at the pumps in the United States is a nominal blend of 90% gasoline and 10% ethanol. This mixture is commonly referred to as E10. This paper reports on a study conducted to determine the effects of E10 on the fuel system performance of vintage automobiles. The study focused on the potential degradation in performance of the carburetors and fuel pumps due to exposure to E10. Six fuel systems were selected for study including the 1948 Flathead Ford, 1958 Volkswagen Beetle, 1962 Ford Falcon, 1969 Chevrolet Bel Air and 1970 Chrysler New Yorker. The components tested were either rebuilt original equipment or new aftermarket replacement parts, depending on availability. Although the components tested were not all original equipment parts, they represent a reasonable sample of the types of parts likely to be found in vintage vehicles currently on the road. The fuel system components were tested under both dynamic and static conditions. The dynamic tests were designed to study the operational performance of the components. For dynamic testing, two sets of components were acquired for each model fuel system. The components were assembled in test rigs that mimicked their operation in a vehicle. One set was tested using straight pump-grade gasoline (E0) and the other set was tested using pump-grade E10. The systems were operated for 1600 to 2400 hours at a 25 percent duty cycle. In addition to the run hours, the fuel systems were allowed to sit idle and exposed to fuel for an additional 2600 hours between run cycles, for a total exposure time of 4200 hours. Periodically the fuel pump flow rates and pressure heads were measured. All systems were found to be performing normally throughout the test period. After completion of the testing each component was disassembled and examined for signs of material damage. The most common observation was staining and tarnishing. Nothing was found that would suggest the imminent failure of a part. The static exposure tests were designed to identify material damage caused by alternately wetting and drying the components. These tests were conducted on a third set of components which were cut into sections and periodically sprayed with either E0 or E10. The periodic exposure, a 5 minute soaked followed by a 55 minute dry time exposure in air, was intended to accelerate potential swelling/shrinking problems with seals/gaskets and corrosion problems on metals. After 3000 hours of exposure minor changes were noted, but nothing that would suggest imminent failure of a part.
Davis, Gregory, Hoff, Craig
Ethanol Impacts on Fuel Supply Parts of Gasoline Engines in Thailand2009-32-011211/3/2009
In Thailand, gasoline mixtures with 85% ethanol by volume so called E85 recently available with guaranteed lower selling price are expected to replace the former types of gasoline. The looming change leads to certain concerns on material compatibility with E85 for automobiles deliberately not designed to run by the blends. Fluid immersion tests complying with SAE and ASTM standard were performed to the parts. The metallic and polymeric parts were submersed in test fluids inside an oven in which temperature had been maintained at 55 ± 2°C for at least 2000 hours. Weekly collected data, i.e. physical appearances and physical properties, were statistical evaluated for parts' compatibility to E85 by comparing the data to those collected derived from the other parts submersed in E10 test fluid. A significant level of differences indicates incompatibility of a part with an assumption that the part is already compatible with E10.
Charoenphonphanich, Chinda, Buanak, Kalong, Kansuwan, Panya
RATING THE PERFORMANCE OF BRAZILIAN FLEX FUEL VEHICLES2005-01-22065/11/2005
This paper presents the results attained in a study carried out by the PETROBRAS Research Center (CENPES), in a comparative analysis made between two flex fuel vehicles (designed for both Brazilian gasohol and hydrated ethanol in mixtures of any proportion) and similar models designed only for gasohol use. This evaluation was based on the effects of the new technology on the driveability, vehicle speed recovery performance, exhaust gas emissions (THC, CO, NOx and aldehydes), fuel economy and maintenance costs
Vicentini, Pedro Caffaro, Kronberger, Stefan
Compatibility of Elastomeric Materials with Gasohol2004-28-00621/16/2004
Considering the benefits associated with use of Gasoline doped with Ethanol, viz, cleaner environment, energy security, boost to agrarian economy, opening of new avenues of employment in rural sector, Government of India mandated the use of 5% Ethanol blended Gasoline (henceforth referred to as Gasohol) effective from January 2003 in 9 States and 4 Union Territories. During the implementation of Gasohol, certain compatibility issues related with elastomeric components used in the Fuel Dispensing Equipment and vehicles were reported. To understand the compatibility of different elastomeric materials with Gasohol, a laboratory study was carried out with the elastomeric components that are being presently used in the Fuel Dispensing Equipment and vehicles. Test results obtained in the laboratory were found to be co-relating with the field experience. The details of this study are reported in this paper.
Nihalani, I., Paulmer, R.D.A., Rao, Y.P.
Fleet Experience Using Three Blends of Ethanol and Unleaded Gasoline80136110/1/1980
The Savannah River Plant, which is operated by the Du Pont Company for the Department of Energy, has successfully operated automotive and nonautomotive gasoline-powered equipment on three different blends of ethanol and unleaded gasoline. The conventional gasohol blend of 10% ethanol and 90% unleaded gasoline (10/90) has been used in addition to 15/85 and 20/80 blends. The plant fleet contains approximately 900 automotive and 250 nonautomotive units. The gasohol program began in July 1979. By October 1980, close to ten million miles will have been driven and almost one million gallons of gasohol consumed.
Joseph, J. W., Grogan, D. M.
Gasohol: Laboratory and Fleet Test Evaluation8008928/1/1980
An experimental program was conducted as a cooperative effort between the Southwestern Bell Telephone Company and the Department of Energy’s Bartlesville (Okla.) Energy Technology Center to determine the effects of a gasohol fuel when compared to a control gasoline. The test vehicles used in this program were separated into two groups--a test fleet and a control fleet. The vehicles consisted of several vans, trucks, and automobiles routinely used in commercial service. The laboratory analysis included testing the vehicles on a controlled environmental chassis dynamometer at a constant ambient temperature of 75° F. Field measurements and data collection included road driveability, in-use fuel economy, and fuel system failures. Laboratory analysis provided information on exhaust emissions, fuel economy, and trace metals in the crankcase lubricating oils. The effect of varying the chassis dynamometer inertia weight was also examined. A reduction in regulated exhaust emissions was found with gasohol, but there was considerable variation among the vehicles. No difference was detected in vehicle fuel economy at actual load weights. Unregulated emissions were higher for gasohol, but the absolute levels were low. The fuel economy with gasohol relative to gasoline was improved as the vehicle weight was increased. A larger quantity of copper was found in the crankcase lubricating oil of the vehicles operating on gasohol when compared to the vehicles operating on gasoline. Driveability was poorer with gasohol, especially during the winter and summer seasons.
Gurney, M. D., Allsup, J. R.
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