A bad smell could indicate an infection like thrush, you should get checked out at the doc. Some people get thrush without any of the other symptoms. Unless infected or particularly....ahem...shall we say "unclean", that area shouldn't smell, and certainly not so that you can even smell it yourself.
There is something in that hormones can affect pheromones etc so maybe it does change down there, but as max says, possibly an infection tho I wouldnt imagine it would only smell when youre ovulating
Pasta, I avoid feminine washes, as they cause Thrush. As I said, it's only a problem before my period. I always have a heavy discharge too and have to wear panty liners all the time.
When I asked my Gynaecologist, he just said some women are juicier than others, which I found a bit disturbing.