greybeard
Well-known member
Natural gas is a much better fuel than straight gasoline, E10, E85, or E100 (100% ethanol) . It has to do with the energy content and more importantly, the stoichiometric efficiency of each. For gasoline, it has a value of 14.7 which means under optimum conditions, modern auto/truck engines need and use 14.7 parts air to every part gasoline. The amt of fuel in this value is 6.8% for gasoline. This, is the standard benchmark that has been set for decades--14.7:1, because gasoline was the primary fuel for so long, and this is the target that other fuels try to meet or beat. (BTW--No engine can burn it's fuel/air mix at 14.7:1 under all conditions--it is changed via inputs from either carburetor throttle plate or fuel injection controls to keep from burning up pistons)
Any fuel that has a lower stoichiometric rating, is using more fuel (by mass) to air ratio to achieve the same energy output.
Diesel is very close to gasoline. 14.6 air to 1 part diesel (14.6:1)
Ethanol in E-10 blends (90% gasoline-10% ethanol) which is what most gasolines sold today are, is rated at 12.7:1 stoichiometric value. The engines are running richer than they were with 100% gasoline. Poorer fuel economy than would be possible with straight gasoline.
E85 (85% ethanol) gets a 9.8:1 stoichi rating.
Pure Ethanol has a 9.00:1 stochi but no internal combustion engine can start on 100% ethanol.
Natural gas on the other hand, has a 17.2:1 stoichi rating, better than any other fuel commonly available today.
Propane has a 15.5:1 stoichi rating. Better than gasoline or E blends, but not as good as NG.
Hydrogen, should it ever be perfected for fuel cells in vehicles, beats them all with a 34:1 rating. (I won't see it happen in my lifetime)
And for illustration purposes, (or for you few with Stanley steamers still out there) wood has a 6.1:1 Stoichi rating. Terrible, but it's cheap enough.
Any fuel that has a lower stoichiometric rating, is using more fuel (by mass) to air ratio to achieve the same energy output.
Diesel is very close to gasoline. 14.6 air to 1 part diesel (14.6:1)
Ethanol in E-10 blends (90% gasoline-10% ethanol) which is what most gasolines sold today are, is rated at 12.7:1 stoichiometric value. The engines are running richer than they were with 100% gasoline. Poorer fuel economy than would be possible with straight gasoline.
E85 (85% ethanol) gets a 9.8:1 stoichi rating.
Pure Ethanol has a 9.00:1 stochi but no internal combustion engine can start on 100% ethanol.
Natural gas on the other hand, has a 17.2:1 stoichi rating, better than any other fuel commonly available today.
Propane has a 15.5:1 stoichi rating. Better than gasoline or E blends, but not as good as NG.
Hydrogen, should it ever be perfected for fuel cells in vehicles, beats them all with a 34:1 rating. (I won't see it happen in my lifetime)
And for illustration purposes, (or for you few with Stanley steamers still out there) wood has a 6.1:1 Stoichi rating. Terrible, but it's cheap enough.