I'm assuming you changed the brakes of your car, no?
If true, I remember my school bus driver telling me about it some time ago (I almost fell asleep

) when a burning smell filled the bus, and smoke was coming out beneath the dashboard.
He said that he had just changed the brakes, and that it was normal for a few days. So I don't think think it's anything to worry about, unless it doesn't stop in a few days.