It is possible to animate the emission of the smoke in smoke sim? I tried to insert keyframes in the fuelAmmount propierty in the flow object but it didn't work. Thanks.
Controlling the amount of fire by keyframing the Flame Rate works for me:
However it doesn't affect the smoke.
To affect the smoke as well, you could try animating the Volume Factor:
I just came on this answer today as I was also looking to animate my smoke/fire animation and although gandalf3 gave me a direction to go in I found that if you set the Surf(Surface) property of the Flow Source to 0 at the start of the animation and keyframe it and than set it to a larger value, i.e. 1, at a second frame and keyframe it and than return the value to 0 at a third keyframe the smoke and fire will turn on at your beginning frame and off at the last frame.
Example: Set your Surface property value to 0 at frame 1 and insert a keyframe in the Surf property box and than advance the Current frame value to 10 and adjust the Surf property value to 1 and insert a keyframe in the Surf property box and than advance your Current frame value to 20 and set the Surf property to 0 and insert a keyframe. This eliminates the need to adjust two properties, instead only adjusting one. As I am new to this forum I have yet to be able to upload video as gandalf3 has above so I am hoping there is not a problem with me just pointing to gandalf3s video above to have those interested in this technique see the Surf property that I speak of, which is located just above the Vol property(Volume Factor) he mentions. Hope this adds to the solution appropriately. Happy Blending all.