That still sounds bad, but consider that the fumes don't come into contact with the burger, the exhaust just heats the metal grill.
Still, it's not exactly aesthetic.
Implications - The idea is great for anyone on a road trip and short on cash or needs food in a pinch. The bonus of using your car's exhaust to heat up a metal grill is that it saves energy because you are actually driving as you cool the burger. The team of designers actually thought up the idea for a competition hosted by Designboom called Dining in 2015. Over 400 designers from all around the world took part in this interesting competition.