[David]

The fluid would be under very high pressure when compressed and probably under low pressure when uncompressed (with a bladder and nitrogen) so uncontrolled fluid ballast shouldn't be a problem.

Leakage would be a concern, but hydraulics have been used for a very long time so repair shouldn't be much of a problem.

It will obviously weigh more than no hybrid system but it should weigh considerably less than electric hybrid and the energy recovered should make up for the weight.


Cars and trucks give up so much energy as brake heat, that it seems like something should be done to recover it.

Maybe F1 technology will bring flywheels to street cars, but whatever we end up with, it seems silly to give up so much energy as heat.