What is this for?

[kargador]

I found a tear on a plastic hose that branched off from the exhaust pipe and is connected to the air cleaner box. I removed the hose and started the engine, there was no perceptible change in the idle and operation of the engine. I wrapped duct tape around the tear and reinstalled the hose. The engine note sounded the same.

What is this for? Is the engine recycling the exhaust gases?

Thanks.

[lzpoor]

i am pretty sure it is for hot air on cold starts