2004 XC90. What is this little bladder device?

[Grawburg]

There is a small black hose coming from under the fuse box, goes to a small device that I found cracked. From this device is another tube that goes to the exhaust manifold.

The device is a small plastic cylinder that was cracked and inside is a small rubber bladder with a stem. The bladder disk is about an inch in diameter. This device is connected to a control or power plug as well.

I can't find anything on a diagram and I am new at DIY car repair. What the heck is this thing?