My car smokes but only like 20mins after I drive it...whats wrong with it?

I have a 1999 plymouth breeze and when I drive it, like 20 mins later I start to smell smoke then 5-10mins after smelling it I start to see it.. The engine isnt over heating and when I look under the hood I see nothing looking like its bout to catch on fire. Once I turn off the car for about 10mins then start it back up the same process repeat it self... whats wrong with it?