🔍 Key Concepts

• Trace the airflow path from the air intake through the turbocharger and into the scavenge air receiver/air box in the illustration. • Think about what happens at low load vs. full load on a large 2‑stroke diesel and when an auxiliary blower is normally needed. • Consider whether the piston in a crosshead 2‑stroke actually pumps fresh air into the cylinder, or if it mainly uncovers scavenge and exhaust ports.

💭 Think About

• Follow the arrows and ducting in the drawing: where does air first enter, what machine compresses it, and where does it collect before entering the cylinder? • At very low engine speed, is there enough exhaust energy to drive the turbocharger effectively, or is another device used to maintain sufficient scavenge air? • Look closely at the piston and liner: does the piston have any separate intake-pumping space (like a crankcase pump), or is air supplied from an external charging system?

✅ Before You Answer

• Identify the component labeled at the top of the drawing that resembles a turbocharger compressor and note when it is effective. • Look for any auxiliary blower or motor-driven blower connected to the scavenge receiver and think about when it would operate. • Verify from the illustration whether there is any crankcase-compression or pumping space below the piston that would draw in and push out intake air, or if all air comes from pressurized scavenge air.