🔍 Key Concepts

• Scavenging in a two-stroke diesel engine and what happens during the short time both intake and exhaust ports/valves are open • The purpose of removing exhaust gases and replacing them with fresh air in the cylinder • How a proper air charge affects combustion efficiency, power, and temperature in the cylinder

💭 Think About

• When the piston uncovers the ports in a two-stroke diesel, what is the main job of the incoming air: is it about fuel, cooling, or clearing the cylinder? • If scavenging works correctly, what happens to the amount and quality of fresh air available for the next power stroke? Does that make the exhaust gas temperature generally higher or lower? • Which answer choices clearly conflict with the basic idea that scavenging is meant to improve engine breathing and efficiency?

✅ Before You Answer

• Be very clear on the definition of scavenging: it is about the gas exchange process, not fuel delivery • Ask yourself: does scavenging increase or decrease the amount (and usefulness) of fresh air in the cylinder? Eliminate any choice that suggests the opposite • Check which option best matches the goal of improving cylinder clearing and fresh air charging, not directly cooling a specific part or heating exhaust gases