🔍 Key Concepts

• Identify from the illustration whether this is a 2-stroke or 4-stroke diesel (look at the valves, camshaft, and ports). • Relate engine type to crank rotation needed for one cylinder to complete a full operating cycle (intake–compression–power–exhaust). • For a multi‑cylinder engine, the crank angle between firing events is total cycle degrees ÷ number of cylinders.

💭 Think About

• From the valve arrangement and lack or presence of scavenging/ports, what tells you if this is a 2-stroke or 4-stroke diesel? • Once you know how many degrees of crankshaft rotation are needed for one cylinder to fire again, what extra information would you need to know to determine how many degrees it takes for all cylinders in the engine to fire once? • Look carefully at both the written question and the cutaway: do they anywhere state or clearly imply how many cylinders this engine has?

✅ Before You Answer

• Be sure you have correctly identified the engine as 2-stroke vs 4-stroke using visual clues (valves, ports, cam arrangement). • Confirm how many crankshaft degrees correspond to one complete cycle for this engine type before thinking about all cylinders firing. • Double‑check whether the problem actually provides the number of cylinders; if not, consider what that means for picking among the answer choices.