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Kobb
I don't have the tools to determine the data for myself and I know not where to find them, so I figure asking is better.

Does anyone know where I can find:

1. The explosive energy of a liter of hydrogen when combusted.
2. Same, except for gasoline.
3. The energy output of a moderate sized Stirling engine, preferably in Joules.
4. The energy required to electrolyze one liter of salt water at room temperature. (Would it be in voltage or watt-hours?)
5. The energy required of a four cylinder, four stroke internal combustion engine to make one revolution of a normal automotive drive train.

I'm experimenting with my car's efficiency.
buttershug
1 and 4 would be equal or maybe 4 is bigger due to losses.
Enthalpy
1) 57,8kcal/mol H2 when H20 is liquid. 300K 1bar.

2) 44MJ/kg for every oil distillate except the lightest gases.

3) ??

4) Salt water will produce chlorine and hypochlorite instead of oxygen. Beware, toxic. Use an acid or a base instead of salt, then as 1) with little losses if well built.

5) I'd say these losses account for 5 to 10% of the total power

buttershug
Would number 5 really be that low?
And of course it would have to be a well tuned engine.
But I thought that reciprocating cylnders would make it less than 90% efficient?


In any case I would bet a couple of dollars that the OP was hoping to find a way to make number 4 significantly less than number 1.
Enthalpy
When running under favourable conditions, a reciprocating engine can deliver about 40% efficiency, though already Carnot's maximum is limited, so only under half of the available work is lost. From this half, the gearbox alternator blower pumps etc lose a lot, meaning that moving the pistons and crankshaft doesn't waste that much.
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