🔍 Key Concepts

• Relationship between scavenging and moving air into and out of the cylinder • How engine work is affected by resisting forces in the gas exchange process • Common terminology for horsepower or power used to overcome gas flow resistance

💭 Think About

• Think about what happens to the piston during the intake and exhaust stroke when there is resistance to flow through ports and valves. • Which term is commonly used for the power needed to push fresh air in and burned gases out against a pressure difference? • Eliminate options that are clearly related to other specific parts of the cycle (such as compression or just valves).

✅ Before You Answer

• Match the term to gas exchange (intake/exhaust) work, not compression work. • Check which option refers to overcoming flow resistance and pressure difference during scavenging. • Verify which term is widely used to describe the indicated power lost in moving charge and exhaust gases in and out of the cylinder.