🔍 Key Concepts

• Relationship between crankshaft speed and camshaft speed in two-stroke diesel engines • How frequently valves or fuel injection events must occur in a two-stroke versus a four-stroke cycle • Mechanical drive of the camshaft (gear or chain) relative to engine RPM

💭 Think About

• Ask yourself: In a two-stroke engine, how many crankshaft revolutions occur for each full operating cycle (intake + compression + power + exhaust)? • Compare that to a four-stroke engine: how many crankshaft revolutions per cycle there, and how does that affect camshaft speed? • If the crankshaft is turning 950 RPM, should the camshaft turn at the same speed, half the speed, or double the speed in a two-stroke design?

✅ Before You Answer

• Be very clear whether the question is about a two-stroke or a four-stroke engine – that changes the relationship. • Recall: valve or injection timing events must repeat once per cycle per cylinder – link that to how many crank revolutions equal one cycle in a two-stroke engine. • Eliminate any option that would make valve/injection events occur at the wrong frequency (too often or not often enough) for a two-stroke cycle.