After reading the 2013 Formula SAE rules I am still a little uncertain about the rules concerning kers. I am thinking of using an electric motor for regenerative braking together with an IC engine. I cannot find any rule that states it is prohibited but this rule (IC.1.1.1) makes me a little uncertain. It says:
"This rule says electric motors running of stored energy are prohibited but what if all the energy used in the electric motor is generated while braking the car during a race? Or does this rule forbid any use of kers combined with IC engines?The engine(s) used to power the car must be a piston engine(s) using a four-stroke primary heat cycle with a displacement not exceeding 610 cc per cycle. Hybrid powertrains, such as those using electric motors running off stored energy, are prohibited. Note: All waste/rejected heat from the primary heat cycle may be used. The method of conversion is not limited to the four-stroke cycle."
How do you think "stored energy" can be interpreted?