Volatility Characteristics of Gasoline-Alcohol and Gasoline-Ether Fuel Blends

Phase equilibria of ethanol fuel blends

“…An example of changes in RVP with addition of ethanol is seen in Fig. 3 [8]. The increase in RVP sharply rises until it hits a maximum at approximately 4-5 vol.% ethanol and very gradually decreases at levels higher than 4-5 vol.%.…”

“…The resulting RVP of the 5 vol.% mixture would be greater than either of the two blend components. This is one example where "commingling" of ethanol fuels can cause unexpected consequences, potentially leading to off-spec gasoline [8,10,11].…”

Vapor Pressure Response to Denaturant and Water in E10 Blends

“…The increase in RVPE of an E10 gasoline blend over that of the raw gasoline is generally accepted and has been shown to be 1 psi (7 kPa), with blends as low as E5 resulting in increases approaching 1 psi (7 kPa). 2 This effect may also extend to gasoline and denaturant-alcohol blends. Absolute ethanol is a single component liquid, which, when mixed with other single component liquids, is predictable in its effect on vapor pressure.…”

“…Formation of azeotropes between alcohol and light aliphatic hydrocarbons is known 34 and is cited as a major cause of increased RVPE in E10 blends. 2 In this study, vapor pressures of gasolines and gasoline-ethanol blends over the moisture range from asreceived moisture to near-saturation were measured to determine whether formation of azeotropes between water and alcohol, or water and organic species, might also affect RVPE. Figures 4 through 7 show that RVPE increases as water content increases, although none of the three E10 gasolines tested were affected identically by the addition of water.…”

Performance Evaluation of an Ultra-Lean Combustion Studies in IC Engines

“…Ethanol have high octane rating and it gives the ability to operate at higher co mpression ratios without pre-ignition [13], ethanol have greater latent heat of vaporization g ives a higher charge density through increased charge cooling [14] and ethanol's higher laminar flame speed and lower flammability limit allo ws it to be run with leaner, or more dilute, air fuel mixtures [15]. In addit ion, ethanol fuels generally yield lower criteria pollutant emissions than gasoline [16,17], lower evaporative emissions due to somewhat lo wer vapor pressures [18] and when certain renewable feedstock's are used, lower life cycle greenhouse gas emissions [10][11][12]. Feel strongly that all internal co mbustion engines control the aggregate of power by controlling the amount of air that is swallowed in the engine, then supplying adequate fuel to efficiently burn.…”