ok, I didn't put it together that you wanted to use your flywheel thing as wheel motors and engine pumps.
Patents, blech, don't want to take this thread there, as bad or worse as they are good. If you are interested in money, try a patent, if you want to make the world a better place, share what you know.
But your specific agenda aside, here is some hydraulic vs electric efficiency picks I found. I assume this is just for motor mode, so double the losses for comparison to peak efficiency of a parallel hybrid.
according to the pics, you can cover a much wider range of conditions at higher efficiency with hydraulic transmission.
I did see one road vehicle that has a hydrostatic transmission
2009 Honda DN-01 - Specifications - Honda.com
though it seems a little piggy @ ~600 lbs.
wikipedia lists it at 48mpg,
Its 5 speed cousin, the nt700v, is listed at 50mpg, 562 lbs, and $4500 less per the honda site.