What is the purpose of a pressure relief valve in a constant displacement pump?

A pressure relief valve in a constant displacement pump is designed to maintain system pressure within specified limits by redirecting excess fluid. When the system pressure exceeds the predefined threshold, the relief valve opens to allow excess fuel to flow back to the inlet side of the pump, thus preventing over-pressurization. This function protects the system components from damage that could occur if the pressure became too high while ensuring a consistent flow of fuel to the engine or other components.

This valve plays a crucial role in maintaining the integrity and safety of the pumping system, ensuring that ideal operational conditions are upheld, which is vital for optimal performance. By returning excess fuel, the relief valve contributes to maintaining the necessary pressure without necessitating further adjustments in the pump's output. This aspect of fuel management is essential for efficient engine operation and overall system reliability.