FAA Powerplant Written Practice Test

To relieve excess pump pressure in an engine's internal oil system, most engines are equipped with a?

1. Bypass valve

2. Relief valve

3. Pressure control valve

4. Flow restrictor

The correct answer is: Relief valve

In an engine's internal oil system, a relief valve is designed specifically to manage and regulate excess pressure that may build up due to various operating conditions. When pressure exceeds a predetermined level, the relief valve opens, allowing oil to flow back to the sump or reservoir. This prevents damage to engine components caused by excessive pressure, ensuring the system operates safely and effectively. While a bypass valve may redirect flow under certain conditions, its primary function is not solely to relieve pressure but to allow oil to bypass a filter during periods of high flow or when the filter is clogged. A pressure control valve could imply regulation of pressure in different contexts, but it may not specifically provide the same function as a relief valve in terms of safety. A flow restrictor primarily limits the flow rate in the system, not pressure, so it does not serve the same purpose as the relief valve. Thus, the relief valve is the most appropriate component for relieving excess pump pressure in an engine's internal oil system.