Nomographs and an equation (shown below) have been developed for estimating the fuel vapor generation from a vehicle fuel tank as a function of fuel volatility (Read vapor pressure) and fuel tank temperature increase.
where A, B, and C are the constants and are equal to 0.00817, 0.2357, and 0.0409, respectively, for gasoline at sea level; T1 and T2 are the initial and final tank temperatures, respectively, in °F; and RVP is the Reid vapor pressure of the fuel in psi.
Nomographs were developed for estimating the effects of altitude, oxygenated fuels (10% ethanol blends), and tank pressure controls on tank vapor generation. The equation constants were also determined for gasolines at high altitude and for 10% ethanol blends both at sea level and high altitude.
Since tank vapor generation is directly proportional to tank vapor space volume, the equation can be used for estimating vapor generation from any fuel tank. Experimentally measured fuel vapor generations with a wide variety of fuels over a wide range of temperatures were compared with those predicted by the equation; the agreement between the measured and predicted results was excellent (R2=0.97).
where A, B, and C are the constants and are equal to 0.00817, 0.2357, and 0.0409, respectively, for gasoline at sea level; T1 and T2 are the initial and final tank temperatures, respectively, in °F; and RVP is the Reid vapor pressure of the fuel in psi.Nomographs were developed for estimating the effects of altitude, oxygenated fuels (10% ethanol blends), and tank pressure controls on tank vapor generation. The equation constants were also determined for gasolines at high altitude and for 10% ethanol blends both at sea level and high altitude.Since tank vapor generation is directly proportional to tank vapor space volume, the equation can be used for estimating vapor generation from any fuel tank. Experimentally measured fuel vapor generations with a wide variety of fuels over a wide range of temperatures were compared with those predicted by the equation; the agreement between the measured and predicted results was excellent (R2=0.97).