25th June 2008 - 12:41 AM
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.
26th June 2008 - 04:30 PM
1 and 4 would be equal or maybe 4 is bigger due to losses.
28th June 2008 - 03:16 AM
1) 57,8kcal/mol H2 when H20 is liquid. 300K 1bar.
2) 44MJ/kg for every oil distillate except the lightest gases.
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
28th June 2008 - 10:45 AM
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.
29th June 2008 - 01:47 PM
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.