I am trying to do a smoke/fire simulation. I can get "ignition" by setting the Start frame for the Smoke Cache bake. I want the fire to "go out" and the last generated smoke to still drift upwards. Think of a candle going out. The last of the smoke still rises for a moment. Setting the End frame for the smoke cache bake simply freezes the last simulation step. How can I get smoke/fire to cease being generated without freezing the simulation?
You can keyframe the Density parameter on the flow object to make it start and stop emitting smoke.
A simple way is keying the surface value (surface says the distance from mesh to emit smoke/fire). When you lower it to zero, no additional smoke will be generated.