🔍 Key Concepts

• Two-cycle diesel engine scavenging (how fresh air enters and exhaust leaves the cylinder in only one crankshaft revolution) • Difference between ports in the cylinder liner and valves in the cylinder head • Role of turbochargers in supplying air vs. the actual opening into the cylinder

💭 Think About

• In a simple, typical two-cycle marine diesel, what opens the path between the crankcase or scavenge space and the cylinder during the piston’s movement? • Do turbochargers themselves open directly into the cylinder, or do they only compress and deliver air to another component? • Which of the listed items is actually located in the cylinder wall that the piston uncovers and covers during its stroke?

✅ Before You Answer

• Identify which option is a passage/opening in the cylinder liner, not a separate mechanical device. • Confirm which components (if any) are more commonly used in four-stroke engines for intake and exhaust gas control. • Verify that bleeder valves are used mainly for air removal or testing, not as the normal path for combustion air into the cylinder.