🔍 Key Concepts

• Crankcase explosions in diesel engines and how pressure behaves during an explosion • The purpose of an explosion relief (crankcase relief) valve on large diesel engines • Which function is more critical in an emergency: how the valve opens or how it closes

💭 Think About

• Think about what happens inside the crankcase during an explosion: does the pressure spike positively (outward) or drop negatively (inward)? • Ask yourself: in an explosion, what must the relief valve do first and foremost to protect the engine structure and crew? Focus on speed and direction of movement. • Compare the options: which one describes action that best prevents damage from a sudden, dangerous rise in crankcase pressure?

✅ Before You Answer

• Identify whether the main danger is overpressure (too much pressure) or implosion (too little pressure). • Decide if safety depends more on the valve’s quick opening or its quick closing during an explosion event. • Check which options incorrectly focus on slow operation when a rapid response would be needed in an explosion.