You're pretty close Michel. Even as far back as 1963, the Rover Company knew all about exhaust gases recirculation. It is a remarkable piece of engineering. I have a bit of a story to tell about this particular under bonnet item. Back in the old whenever days I drove to Woodford in the Maitland area to pick up an engine that some owner wanted to dispose of. Well, I needed one at the time, and we are talking about 25-28 years ago.
So, I loaded up my 7 by 5 box trailer with the newly purchased engine safely secured by straps and ropes. Whatever was the cheaper at the time. Anyway, we proceeded back to Sydney on the M1 Freeway,as it was known at the time. It was about eight in the evening and obviously pitch black. So, we're going along at about a 100 (kilometres) an hour and heard a few drivers of cars that were overtaking me blow their horns. I really knew of no reason, and basically ignored the horns. Without prompting, Julie who was with me at the time, looked around and exclaimed "your engine is on fire" - the one on the trailer, mind you. Well obviously, I pulled up in the breakdown lane, walked to the trailer and, sure enough, there were smoke and a small flame emanating from the two front openings. Well, well......
In those days, I was a heavy smoker (loved them - I was the 50/50 man) and I would never use an ashtray in any of my cars. I couldn't stand the smell of stale tobacco and the look of cigarette butts, so when smoking, out the window they would go. In this case, the burning butt found its way into one of the two openings, and started to burn the Air Filter that was obviously still in the housing. A quick dismantling, I emptied the contents of the unit and obviously that got rid of the fire and flames. Think about this - at a 100k.s, the butt is flicked out the window and gets blown into one of the openings. One in a million chance ! That's my story and, BTW, it is the Air Cleaner.
Regards Styria
N.B. Go back to the under bonnet picture and have a look at the Air Cleaner !