🔍 Key Concepts

• Scavenging flow patterns and how fresh air moves through the cylinder • Location of intake ports (in liner) versus exhaust valves (in cylinder head) • Meaning of uniflow, loop, and cross‑flow in terms of gas direction

💭 Think About

• Picture where the fresh air comes in on a slow‑speed 2‑stroke and where the burned gases leave—does the flow generally go in one direction, or does it turn back on itself? • Which scavenging pattern is typically associated with engines that have exhaust ports in the liner instead of valves in the head? • For each option, imagine the path of gas: does it cross the cylinder, loop around, reverse, or move more or less straight from ports to valve(s)?

✅ Before You Answer

• Match the presence of exhaust valves in the cylinder head with the correct scavenging type used in large slow‑speed marine diesels • Eliminate any scavenging types you know are linked to piston‑controlled exhaust ports rather than valves • Verify which scavenging pattern has gases moving predominantly in one main direction from intake ports toward the exhaust outlet