You shouldn't be getting any smells like that into the cabin.
First thing, can you pop the bonnet and smell the same smell on tickover? If so it's likely an oil leak and maybe hitting a hot part of the engine and giving off burning oil fumes; these will be notocable in the cabin too.
If you cant smell anything under the bonnet then it's likely to be exhaust gas related and that could be a number of things - cracked/lose exhaust manifold, EGR valve or inlet side to the turbo.
If you are getting exhaust fumes in the car then this is potentially a killer. You need to go back to the dealership and insist they give it a thorough going over