Im really not sure !!!

but I was thinking that the vacuum generated in the one side will require less energy to generate HHO.

also as the piston strokes into this vacuum the piston will
have an extra force applied by the vacuum.

so what we have here is HHO being generated in a vacuum.
and HHO being burned in a higher pressure.

plus the extra umph from the vacuum as the piston strokes towards the vacuum.

3 plusses.

it should be capable of providing enought power to run a generator , that should provide the electricity to generate
the HHO.

and if anythings left over then that is free energy.

so the real difference is that it contains its own fuel
supply that never dimminishes.

because the water is recycled from water to HHO then back to water then back to HHO , etc etc etc.

you just need a battery to start it , just like a car

it probably wont work as fast as a car engine , because there is a time factor involved in the HHO generation
but by using a heavy flywheel the force from the explosions can be transfered into the flywheel that will hold the force until it is used.

although the flywheel could be turning very fast , the
engine rpm could be very low , by using a geared ratio
between the engine and flywheel.

this way the engine can have a slower rpm that will allow
more time between explosions and allowing more time for the build up of HHO gasses.

and you could have several of these inline to achieve more power.

and they could be timed so you would have a more balanced
fireing order and power input to the flywheel.

I think it really would work !!!

can you think of anything that would stop it?

3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.