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Energy need is one of the indispensable needs of human beings. At this point, the important thing is to use the available resource that is sustainable, economical, and sensitive to the ecosystem. For this reason, alternative fuels will maintain their importance in the future as they do today. Internal combustion engines continue to be used as power plants for conventional and hybrid vehicles. The sustainability of internal combustion engines depends on their energy consumption and the emissions released. In this study, the effects of E85 and gasoline on NO emissions have been investigated experimentally by considering ignition timing and relative air/fuel ratio in a spark ignition engine. The experiments have been performed on the Ricardo Hydra research engine at 2000 rpm engine speed and a 10:1 compression ratio. The experimental results show that engine output power obtained using E85 was similar to or higher than that of E0. The exhaust gas temperatures for E85 decreased by an average of 22.6 °C, compared to E0. When all experimental data obtained with E0 and E85 were compared with each other, it was seen that gravimetric fuel consumption and brake specific fuel consumption were increased on average by 39.3% and 37.5%, respectively. The results of this study show that especially the improvement of E85 in NO emission is remarkable. Considering the maximum NO point at 1.05 or 1.1 relative air/fuel ratio, a 38.4% reduction in brake specific NO was obtained with E85.

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The direct injection of ethanol-gasoline blended fuel into the engine cylinder near the top dead center (TDC) is evitable to suffer from the wall impingement due to more injection mass required to maintain the same air/fuel ratio with traditional fossil fuels. In this study, the evaporation characteristics of E85 cold-start impinging spray were investigated by experiments and numerical simulation. A constant volume vessel was used to produce the direct-injection spark-ignition (DISI) engine-like conditions. The ultraviolet (UV) – visible (Vis) dual-wavelength laser absorption scattering (LAS) technique was employed to quantitatively measure the individual components evaporation in E85, with the emphasis on the effects of impinging distance, wall temperature and injection pressure on the mixture formation. The results show that although the larger impinging distance rarely influences the evaporation before impingement, it facilitates the E85 evaporation process after impingement due to the better atomization by low boiling point (LBP) components (e.g. ethanol). The effects of cold-start wall temperature on the E85 impinging spray are greatly dependent on the impinging distance. Under the small impinging distance, the ethanol and low boiling point (LBP) components of gasoline evaporate faster after impingement at higher wall temperature, but such effect becomes absent under long impinging distance. Therefore, the smaller impinging distance shows a higher sensitivity to wall temperature. Lower wall temperature leads to a high wall heat transfer, thus potentially extend the evaporation time at the near wall region along the spray axis. At either impingement timing or initial impingement, the LBP component with high latent heat evaporates fast, leading to a decrease of surrounding gas temperature. Increasing injection pressure helps to greatly improve the evaporation of the high boiling point (HBP) component in gasoline under cold-start impingement. The evaporation ratio of E85 increases up to about 18% ∼ 30% than that of E100 at the initial impinging period under cold-start condition.

A two-tracer laser-induced fluorescence technique is used to quantify the effects of preferential evaporation of multicomponent fuels on the fuel component distribution. The technique is based on the simultaneous detection of the fluorescence of two aromatic tracers with complementary evaporation characteristics matched to different components of a multicomponent fuel. Relative variations in the spatial distribution of tracer distribution as a consequence of preferential evaporation are determined from the ratio of laser-induced fluorescence signals measured within two distinct spectral bands. A thermodynamic model is then used to relate the ratio map with the fuel component map. The accuracy and precision of the method are characterized from determining the laser-induced fluorescence signal ratio within two identical spectral bands. Measurements are performed in a high-pressure high-temperature vessel equipped with an eight-hole injector. The Engine Combustion Network Spray G target conditions are chosen as reference conditions at injection. The only difference with these target conditions is the use of a multicomponent surrogate fuel. Parametric variations around these target conditions are also performed in order to investigate their effect on the preferential evaporation effect. The ambient temperature is varied between 525 and 625 K and the injection pressure is reduced from 200 to 100 bar. The impact of ethanol addition is also studied with two different fuel mixtures in addition to the reference surrogate fuel: E20 and E85 which feature 20% and 85% of pure ethanol within surrogate, respectively. A significant preferential evaporation effect is observed in this condition representative of engine applications and results in a spatial segregation between low- and high-volatility fuel components, respectively, at the tail and tip of the plumes. This effect is enhanced by the addition of ethanol and the decrease in ambient temperature and injection pressure. [ABSTRACT FROM AUTHOR]

Alternative fuels, such as ethanol-based fuels (E85), have attracted attention as promising approaches for reducing emissions from on-road mobile sources. However, the in-vehicle exposure to pollutants when using E85 has not yet been addressed. This study aims to examine the contribution of E85 to in-vehicle exposure to carbon monoxide (CO), nitrogen dioxide (NO2) and total volatile organic compounds (TVOCs) under different scenarios. A one-compartment mass-balance model incorporating outdoor concentration, infiltration, makeup and recirculated air exchange rate (λ), volume of the vehicle (V) and the internal emissions source (E) is developed to obtain the in-vehicle concentrations. The intake fraction (pollutant mass inhaled by an exposed individual per unit release of pollutant) was used to estimate the mass emission rate. The results show a small increase in interior CO and TVOC concentrations for vehicles fueled by E85 compared to those fueled by gasoline, mainly due to the increase in mass emission rate resulting from the exhaust system when E85 is burned. The in-vehicle concentration of CO and TVOCs for ethanol-fueled vehicles ranged from 6.2 to 42.2 mg/m3 (5.4–36.2 ppm) and from 67.9 to 1851 (µg/m3), respectively. The maximum increases in CO and TVOC concentrations were 2 (mg/m3) and 303.3 (µg/m3), observed when the air exchange rate was 2 h−1 and the vehicle was stationary. Despite the increase in CO and TVOC levels, the penetration of E85 positively impacted in-vehicle NO2 concentrations, with a maximum reduction of 293 (µg/m3). The study also developed a mathematical model to estimate the intake fraction under different scenarios for both E85 and gasoline fuels. The difference in intake fraction of CO is estimated to be in the range (2–1) (mg of pollution is inhaled per kg emitted). The difference in intake fraction of NO2 and TVOCs ranged from 10 to 2 and from 5 to 1, respectively. [ABSTRACT FROM AUTHOR]

The Renewable Fuel Standard (RFS) is among the largest renewable energy mandates in the world. The policy is enforced using tradeable credits that implicitly subsidize biofuels and tax fossil fuels. The RFS relies on these taxes and subsidies to be passed through to consumers to stimulate demand for biofuels and decrease demand for gasoline and diesel. We study pass-through of the RFS subsidy for E85, a high-ethanol blend fuel, to retail fuel prices using weekly prices from over 450 fuel stations in the United States. We find that, on average, half to three-quarters of the E85 subsidy is passed through to consumers. However, pass-through takes 6–8 weeks, and station-level pass-through rates exhibit substantial heterogeneity, with the retailers' market structure influencing both the speed and level of pass-through. [ABSTRACT FROM AUTHOR]

We show that the cost of increasing biofuel mandates given a binding ethanol blend wall falls disproportionately on diesel fuel consumers. The extent of the burden on diesel fuel consumers is explained neither by their relatively more inelastic demand nor by blenders seeking to capitalize on the biodiesel tax credit. Relaxing the blend wall constraint by increasing the potential demand for high-ethanol blends is the only effective lever to insulate diesel fuel drivers from the one-sided welfare impacts of rising mandate levels. The independent effects of the nested mandate structure and the joint compliance base under the Renewable Fuel Standard (RFS) generate the link between motor gasoline and diesel fuel markets. Our results highlight the importance of evaluating the incidence of the RFS in a holistic framework taking both ethanol and biodiesel into account. [ABSTRACT FROM AUTHOR]

Abstract We examine the pass-through of wholesale prices to retail prices in the market for E85, which contains 51%–83% ethanol, and in the much larger market for E10, which contains 10% ethanol. We use a panel dataset consisting of monthly observations from 2007 to March 2015 on wholesale and retail prices for 274 Minnesota gas stations that sell both E10 and E85. Consistent with prior research, the cumulative pass-through coefficient for E10 is 1.00 after one month. In contrast, the E85 market is sparse, and although pass-through increased over time, we estimate it to be only 0.53 statewide from 2012 to 2015. Pass-through is higher at stations with more local E85 competitors. In the Twin Cities, which has a high density of E85 stations, pass-through is nearly complete, but outside the Twin Cities slightly less than half the wholesale discount of E85, relative to E10, is passed on to the consumer. [ABSTRACT FROM AUTHOR]