FAA Powerplant Written Practice Test

What device is used to relieve excess pump pressure in an engine's internal oil system?

1. Flow control valve

2. Relief valve

3. Bypass valve

4. Temperature regulator

The correct answer is: Relief valve

A relief valve is specifically designed to manage excess pressure within a system, including the internal oil system of an engine. Its primary purpose is to open and allow the excess oil to escape back to the oil sump or the return line when the pressure exceeds a predetermined limit. This function prevents potential damage to the oil pump and the engine by maintaining proper oil pressure levels. In contrast, a flow control valve regulates the flow of oil to different parts of the engine but does not specifically address pressure relief. A bypass valve typically directs oil flow around a filter or other components when certain conditions are met. A temperature regulator focuses on managing the temperature of the engine oil rather than pressure, making it unsuitable for this specific function. Each of these alternatives addresses different aspects of the oil system, which is why they do not serve the same purpose as a relief valve.