What is the fuel pressure-like device's purpose under the car

[Svenska]

RE:1995 850 non-turbo. I just discovered that I have a gas leak under the car that is coming from the vacuum/diaphragm/round shaped device that looks like a fuel pressure regulator. Volvo calls it a "fuel pressure pulse regulator". Mine is completely rusted and leaks. It is an obsolete part from Volvo. My question is, what does it really do? and can I remove it and put a piece of fuel line in its place? It goes to the metal fuel pressure rail on the engine. Any ideas?

[abscate]

It, uh, regulates the fuel pressure. It's important. You should be able to get one off eBay or a junkyard.

Replacing it with straight hose is a bad idea.