🔍 Key Concepts

• Scavenging flow patterns inside a two-stroke diesel cylinder (how the air and exhaust move) • Where ports are located (in the liner) versus valves (in the head) • How uniflow, crossflow, and loop/return flow scavenging differ

💭 Think About

• For each scavenging type, picture how fresh air enters and how exhaust leaves the cylinder—do they move mostly in one direction, or swirl/loop? • Ask yourself: which system usually uses ports in the liner for one function (inlet or exhaust) and a valve in the cylinder head for the other? • Which of these methods is most common on large slow-speed marine diesels with an exhaust valve at the top of the cylinder?

✅ Before You Answer

• Verify which scavenging system is defined by gases moving predominantly in one direction from bottom to top • Check which systems rely only on ports in the cylinder liner and do not need a head-mounted exhaust valve • Confirm in your notes which method is typical for large, slow-speed, two-stroke marine engines with a single exhaust valve in the head