Measurng fuel; why the switch?
04-07-2011, 03:53 PM
#16
Mass does not vary with temperature or any other variable, it is constant.
Cool fuel will have a higher energy/gallon than warm fuel. Underground fuel tanks will not see much temperature change with the change in ambient temperature.
However aboveground tanks, like at the Glen, do see a change with the ambient, so a fuel purchase first thing in the morning would result in more BTU/$. This would show up as more fuel in your fuel can once it warmed up.
For the hell of it I will find out the what the coefficient of thermal expansion is for gasoline to make an approximation of what the actual change would be.
Mike
Cool fuel will have a higher energy/gallon than warm fuel. Underground fuel tanks will not see much temperature change with the change in ambient temperature.
However aboveground tanks, like at the Glen, do see a change with the ambient, so a fuel purchase first thing in the morning would result in more BTU/$. This would show up as more fuel in your fuel can once it warmed up.
For the hell of it I will find out the what the coefficient of thermal expansion is for gasoline to make an approximation of what the actual change would be.
Mike
04-08-2011, 05:46 PM
#17
Looked into the gasoline volume change with temperature. The coeffecient of thermal expansion is 0.069% per F degree. So using an assumption of a 30 F degree temperature increase (dispensed at 60 degrees and heats up to 90 degrees) and a 10 gallon fuel purchase, the change in volume is 0.2 gallons or about 26 ounces. This is a definitely a noticable change and good reason to not completely fill the fuel can.
Apparently the gasoline wholesalers buy and sell their fuel to a temperature corrected standard of 60 degrees F. When we buy it from them and it is over 60 degrees F we just get hosed.
Mike
Apparently the gasoline wholesalers buy and sell their fuel to a temperature corrected standard of 60 degrees F. When we buy it from them and it is over 60 degrees F we just get hosed.
Mike
