I've been reading a lot on the "flybrid" mechanical flywheel based KERS system which was developed for use on F1 cars. I understand the basics of how energy is stored in this system, however, when it is recovered, it is said to provide a constant 60kW of power for 6.67 seconds. I'm confused on how the flywheel is used to provide this constant energy output because to my understanding, as the flywheel slows down, the power that it provides must also decrease. I assume that the CVT is somehow used to maintain this constant power output, but I have no idea how the CVT would change its gear ratios in order to keep the power at 60kW. Could someone please explain?