LONDON, July 6 : Formula One could bring back refuelling and an independent engine maker under plans to switch to V8s from 2031, according to FIA president Mohammed Ben Sulayem.The Emirati said developments could include manufacturers being restricted to supplying engines to only one team to limit their influence on others, with an affordable alternative available from an approved FIA supplier.Mercedes currently supply four teams while Ferrari provide engines to three customer outfits.FAR MORE AFFORDABLE ENGINES The naturally-aspirated V8s would be lighter but require more fuel to run than the current and more sophisticated V6 turbo hybrid engines, a factor that could negate efforts to reduce car weights if tanks were made larger.The alternative would be smaller tanks and refuelling, which