This is a very simple solution to help stop the cockpit on your car filling with exhaust fumes.

I have always found it annoying when out in my car when I open the window slightly to let in some fresh air, but instead end up breathing in a lot of smelly exhaust fumes, and even at times getting sore eyes. I found that when you open the window it is the air already inside the cockpit that gets sucked out, rather than the air outside being drawn into the cockpit.

As the air is being sucked out of the cockpit, it has to be replaced by air from elsewhere inside the car, so it draws air in from inside the boot of the car via the vents behind the rear stereo speakers, and along the inner rear wings into the cockpit via the carpet flaps just behind each seat that gives access to the door locks.