Why does the engine of my Audi A1 produce a knocking noise when I accelerate?

I have noticed that when I press on the gas pedal to accelerate in my Audi A1, there is a distinct knocking noise coming from the engine. It seems to happen more frequently when the engine has been running for a while. Is this a common issue and what could be causing it?

This could be a sign of engine knocking, which occurs when the air and fuel mixture ignites prematurely in the combustion chamber. It can be caused by a variety of factors, such as low-quality fuel or incorrect ignition timing.