🔍 Key Concepts

• engine crankcase explosion protection requirements for medium-bore diesels • how requirements change when cylinder bore increases past certain thresholds • the purpose and location of explosion relief valves on large engines

💭 Think About

• Ask yourself which option is about protecting the crankcase from explosions rather than normal operating features like valves or rings. • Consider which requirement would be specifically triggered by bore size (diameter of the cylinder) rather than being a general design choice for any engine. • Think about where explosion relief valves are typically placed in relation to the crankshaft and crank throws on larger marine diesel engines.

✅ Before You Answer

• Verify which choice mentions a feature that is directly related to safety against crankcase explosions. • Check which option ties the requirement to position along the crankshaft (e.g., per throw or group of throws). • Confirm from regulations or notes that for bores in the 250–300 mm range, engines must have a minimum number and distribution of explosion relief valves.