Clayton,
Because any chemical process is inefficient — and especially a chemical process as clumsy as exploding gasoline vapor.
Actually this is not the case – modern engines are remarkably efficient at burning gasoline. The inefficiency is due to the fact that IC engines use the Rankine thermodynamic cycle, basically you can use the energy between the pressure of the intake charge and the pressure of the exhaust, but much of the heat and some of the pressure gets wasted. In order to use all of the energy you would need to exhaust at the same pressure and temperature as the intake – not possible in the real world.
Dave;
Diesel improves mileage, because diesel fuel inherently contains about 20% more energy than gasoline per volume unit.
The energy content (higher heat value) of diesel and gasoline is similiar, Diesels are more efficient because they operate at higher pressure. Diesel fuel is used in Diesel engines because it’s less volatile, a requirement of the higher pressures involved.
eon
It’s certainly possible to crack water into O2 and H and make it pay commercially
Not as fuel – Hydrogen production from chemicals such as natural gas or petroleum is always wasteful, electrolysis of water used more energy to break the chemical bond than you get back when you burn it. Water it hydrogen that has already been burned (oxidized) you are meerly reversing the process. For this reason Hydrogen is only a way to store energy, it’s not an energy source in itself
