#1Kshitij Neroorkar(UMass: University of Massachusetts Amherst)H-Index: 7
#2David P. Schmidt(UMass: University of Massachusetts Amherst)H-Index: 28
Flash boiling is a physical phenomenon which governs the non-equilibrium phase change of a high temperature fluid as it is depressurized below its vapor pressure. The modeling of this process is of importance to a number of industrial applications and requires the vapor-liquid equilibrium properties of the fluid under consideration. The highly non-ideal nature of gasoline-ethanol fuel blends makes vapor-liquid equilibrium calculations extremely difficult for such fluids. A simple model known as ...
When expressed using volumetric concentrations (as is industry practice), the addition of relatively small amounts of ethanol or methanol (e.g., 10% by volume) to gasoline appears to result in disproportionately large, nonlinear increases in research octane number (RON) and motor octane number (MON). As a result, volumetric “blending octane numbers” are of limited value for estimating the octane number of alcohol−gasoline blends because they vary with alcohol content and base gasoline compositio...
Abstract A detailed chemical kinetic modeling study was undertaken to characterize the auto-ignition behaviour of a full range of blends of both methanol and ethanol with a PRF 80 base fuel. The overall results were encapsulated in a computationally efficient semi-empirical formulation. The auto-ignition model was combined with an ASTM (CFR) engine simulation to explore the underlying causes for the octane number value exhibited by alcohol fuels. The model predictions were validated against expe...
In this brief communication, we present new experimental species profile measurements for the low and intermediate temperature oxidation of ethanol under knock-prone conditions. These experiments show that ethanol exhibits no global low temperature reactivity at these conditions, although we note the heterogeneous decomposition of ethanol to ethylene and water. Similar behavior is reported for an E85 blend in n-heptane. Kinetic modeling results are presented to complement these experiments and e...
Bioethanol is currently a significant gasoline additive and the major blend component of flex-fuel formulations. Ethanol is a high-octane fuel component, and vehicles designed to take advantage of higher octane fuel blends could operate at higher compression ratios than traditional gasoline engines, leading to improved performance and tank-to-wheel efficiency. There are significant uncertainties, however, regarding the mechanism for ethanol autoignition, especially at lower temperatures such as ...
The NOx emission and knock characteristics of a PFI engine operating on ethanol/gasoline mixtures were assessed at 1500 and 2000 rpm with λ =1 under WideOpen-Throttle condition. There was no significant charge cooling due to fuel evaporation. The decrease in NOx emission and exhaust temperature could be explained by the change in adiabatic flame temperature of the mixture. The fuel knock resistance improved significantly with the gasohol so that ignition could be timed at a value much closer or ...
#1Thomas Wallner(Argonne National Laboratory)H-Index: 18
#2Scott A. Miers(Argonne National Laboratory)H-Index: 11
Last. Steve McConnell(Argonne National Laboratory)H-Index: 3
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This study was designed to evaluate a “what if” scenario in terms of using butanol as an oxygenate in place of ethanol in an engine calibrated for gasoline operation. No changes to the stock engine calibration were performed for this study. Combustion analysis, efficiency, and emissions of pure gasoline, 10% ethanol, and 10% butanol blends in a modern direct-injection four-cylinder spark-ignition engine were analyzed. Data were taken at engine speeds of 1000 rpm up to 4000 rpm with load varying ...
Abstract This paper investigates the impact of ethanol on the oxidation of iso-octane at low and intermediate temperatures. Flow reactor experiments are conducted on binary mixtures ranging from neat iso-octane to neat ethanol at temperatures of 650 K and 875 K, a pressure of 10 bar and an equivalence ratio of 0.058, with the intermediate species and gas temperatures measured along the reactor. At 650 K, where neat iso-octane is near the peak of its low temperature chain branching, the addition ...
#1M. Del Pecchia(University of Modena and Reggio Emilia)H-Index: 1
#2Valentina Pessina(University of Modena and Reggio Emilia)H-Index: 1
Last. Stefano Fontanesi(University of Modena and Reggio Emilia)H-Index: 17
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Abstract Several environment agencies worldwide have identified biofuels as a viable solution to meet the stringent targets imposed by future regulations in terms of on-road transport emissions. In the last decades, petroleum-based gasoline has been increasingly blended with oxygenated fuels, mostly ethanol. Blending ethanol with gasoline has two major effects: an increase of the octane number, thus promoting new scenarios for engine efficiency optimization, and a potential reduction of soot emi...
Last. Zhi Wang(THU: Tsinghua University)H-Index: 30
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Abstract Spark assistance in homogeneous charge compression ignition (HCCI) is a promising method to improve combustion stability. Fundamental experiments were carried out in a rapid compression machine along with chemical kinetics analysis to investigate the complete combustion process of spark ignition to compression ignition (SICI) using ethanol-blended fuels. Five fuels, consisting of n-heptane, iso-octane and ethanol with different fractions, are divided into two groups. The fuels with diff...
Abstract This work develops a surrogate fuel that reproduces the octane blending of a market gasoline with ethanol. It first extends our previous investigation that reported strong, non-linear blending for ethanol/paraffin and ethanol/aromatic mixtures (Foong et al., Fuel 2014 p. 727) to consider mixtures of ethanol/cycloparaffin, ethanol/olefin, and hydrocarbons from different groups. On the molar basis, ethanol blends synergistically with cyclohexane and 1-hexene, whereas toluene blends antago...
Last. Zhi Wang(THU: Tsinghua University)H-Index: 30
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Abstract Spark assistance for homogeneous charge compression ignition (HCCI) can control combustion phasing, improve thermal efficiency, and reduce emissions in gasoline engines. As the characteristics of flame propagation determine the control authority of ignition timing, it is important and necessary to investigate pressure dependence of flame speed in the lean-premixed mixture relative to engine operating conditions. Experimental study in an optical rapid compression machine (RCM) and simula...
Last. Thomas D. Foust(CSU: Colorado State University)H-Index: 2
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Abstract Supplementing petroleum fuels with sustainable and renewable alternatives is a good option for increasing the sustainability of transportation fuels. Alcohols are particularly attractive blendstocks for spark ignition engines, mainly due to their desirable fuel properties including high octane, evaporative cooling, and reduced sooting propensity. Although the use of SI engines is widespread around the world, predominately for light duty vehicles, concerns about CO2 emissions and other s...
#1Zongyu Yue(Argonne National Laboratory)H-Index: 5
#2Sibendu Som(Argonne National Laboratory)H-Index: 30
Abstract Engine knock remains one of the major barriers to further improvement in thermal efficiency of Direct-Injection Spark-Ignition (DISI) engines. While Research Octane Number and Motor Octane Number are often used as standard rating methods for knock resistance of fuels, the impacts of other fuel properties on knock propensity in modern engines such as heat of vaporization (HoV) and laminar flame speed (LFS) require better understanding in order to co-optimize fuels and engine designs to a...
Abstract Octane rating is an essential property for gasoline-type fuels because it is the major factor that determines the maximum compression ratio (CR) allowed in spark-ignition engines. In practice, a base gasoline, which is a mixture of various refinery streams, is dosed with octane-booster additives for meeting the minimum octane requirements set by regulation standards. Coal-based methanol is widely used in China as a gasoline octane-booster. In addition to its high octane rating, methanol...
Last. Baolu Shi(BIT: Beijing Institute of Technology)H-Index: 9
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Abstract This study investigated spray mixture formation of ethanol-gasoline blends (E0, E85 and E100) under direct-injection spark ignition-like (DISI-like) condition in a constant volume vessel. An ultraviolet (UV) – visible (Vis) dual-wavelength laser absorption scattering (LAS) technique was used to quantitatively measure the liquid and vapor phase distributions. The toluene with the similar physical properties to gasoline and high absorption for ultraviolet, especially for a boiling point c...
Abstract Improving the efficiency of the internal combustion engine will continue to play an important role in reducing greenhouse gas (GHG) emissions in the transport sector. One promising technology that offers improved engine efficiency is the Octane-on-Demand (OoD) concept. This engine-fuel system makes use of two fuels with different octane quality to match the specific anti-knock requirements of the engine under different driving conditions. Previous research has mainly focused on enabling...