🔍 Key Concepts

• Two-stroke diesel scavenging and how fresh air enters the cylinder • How ports vs valves are typically used in large low-speed two-stroke main propulsion engines • The role of intake flow pattern in creating swirl/turbulence for good combustion

💭 Think About

• Think about whether large two-stroke main propulsion diesels usually have poppet intake valves in the cylinder head or intake ports in the liner • Consider which component actually shapes the direction and speed of the incoming air to produce swirl in a two-stroke engine • Ask yourself which of these options is commonly associated with four-stroke engines rather than low-speed two-stroke marine engines

✅ Before You Answer

• Verify in your notes how air enters a low-speed two-stroke main propulsion diesel (ports in the liner vs valves in the head) • Check which options relate to starting the combustion process (e.g., precombustion chambers) rather than just moving air • Confirm which feature is specifically designed to control the direction and swirl of the incoming air charge in a two-stroke cylinder