What is the role of a pressure relief valve in a fuel system?

The role of a pressure relief valve in a fuel system is crucial for safety. It is designed specifically to release excess pressure that builds up within the system. When gas, such as LPG or CNG, is stored, it is kept under high pressure. If this pressure exceeds safe levels, there is a risk of tank rupture or even explosion, which could pose a severe threat to safety.

Thus, the pressure relief valve acts as a safety mechanism by venting excess pressure to the atmosphere, ensuring that the pressure within the system remains within safe operational limits. This function is essential in preventing catastrophic failures that could result from over-pressurization.

In contrast, the other options do not accurately reflect the primary function of a pressure relief valve in fuel systems, which focus on safety through pressure management. Regulating fuel flow rate or monitoring fuel quality is typically managed by different components within the fuel system altogether, while allowing excess fuel to escape safely is not the intended purpose of a pressure relief valve.