🔍 Key Concepts

• Look closely at how the part labeled 3 is shaped and where it sits in relation to the piston and combustion space. • Remember the difference between a cylinder liner (walls of the cylinder), a cylinder head (top cover of the cylinder), and the valve/rocker mechanism that operates the valves. • Notice the color coding in the drawing that separates cooling/scavenging spaces from solid metal components.

💭 Think About

• Does label 3 point to a solid metal component that closes off the top of the cylinder, or to the inner sleeve that the piston moves inside? • Is the object at 3 mainly part of the gas passage/air space, or part of the structure that holds the valves, injectors, and cooling passages? • Which of the answer choices would logically be directly exposed to combustion pressure at the top of the cylinder where the valves and injector are located?

✅ Before You Answer

• Confirm whether 3 is above or around the piston travel area (wall vs. cap at the top). • Check if 3 clearly includes the valves and rocker arms (that would indicate an assembly, not just a single casting). • Verify whether 3 appears as a hollow gas/air space (would suggest scavenging air space) or as the solid boundary forming the combustion chamber.