the hybrid electric vehicle to exploit regenerative braking for energy savings first is overall turn around efficiency if the cvt is 90 mechanically efficient the overall turn around efficiency would be 0 9 2 81 secondly there is no physical limit to the rate at which a flywheel can accept energy flux one need only accelerate it harder a vehicle described above with only a 10 or 20 hp engine would be operating at maximum load and efficiency all the time it is operating plus because all of the braking energy is reused for accelerations there would never be a situation where the engine is burning fuel at a 70 or 100 hp rate during accelerations the small engine absolutely limits fuel consumption by its size alone the cvt that enables this system requires a very large ratio coverage to handle the extremely wide speed swings this system must accomplish to transform the kinetic energy in operation to accomplish energy transformation during braking the flywheel which initially would be spinning at a relatively low speed would have to be accelerated by the output of the cvt to a very high speed of about 10 000 to 20 000 rpm all the while the input to the cvt from the vehicles driveline would be decelerating from an initial high speed to a relatively low speed this necessitates a cvt with ratio coverage of 100 1 or more likewise to accomplish.