Therefore as water was previously gas before exploding i really think that it will become only superheated steam...
However lets calculate further ...
I do agree as i said that the released heat will probably be enough to convert the water into steam. However
1. how long will it be steam before it has given the heat off to the surrounding environment (chassis) and condenses?
2. the expansion water to gas will make 1860 volume-units out of 1 volume-unit. steam however, depending on temperature, will have less than 1860 volume-units for 1 volume-unit of water -> underpressure
The molecules would not need to be split inside the cylinder, but it would be of advantage:
1. water drops in (when piston is at top center)
2. electricity through it, water drops expand, pressure moves piston down
3. when piston is down (shortly after bottom center), ignite the gas -> water/steam conversion, pressure sinking rapidly
(assumption), heat created
4. underpressure sucks piston up
5. repeat
I'm sure this would not work because of some mistake, i didn't look into a thermodynamics book and probably someone else has thought this through already.
It seems that there is an explosion, then an implosion overall:
[youtube]w7ISu8uT9AE[/youtube][youtube]EabiEQibg1Y[/youtube]
edit: oh wow hho + steam:
[youtube]CMB1isICKiA[/youtube]
Nice channel, someone uses a 1000FPS camera.