What is the cause of the rattling noise in my Audi A4's engine?

I recently noticed a rattling noise coming from my Audi A4's engine while driving. The noise seems to increase with acceleration but does not affect the performance of the car. Any idea what could be causing this?

The most common cause of rattling noises in Audi A4 engines is a loose or damaged heat shield. It is recommended to have a mechanic check and tighten or replace the heat shield if necessary.