🔍 Key Concepts

• Four-stroke diesel cycle sequence (intake, compression, power, exhaust) • Direction of piston movement for each stroke (up vs. down) • What happens to gases in the cylinder right after the power stroke

💭 Think About

• First, list the four strokes of a diesel engine in their correct order and note what the piston is doing in each (moving up or down). • Ask yourself: during which stroke does the engine get rid of burned gases, and during which stroke does it pull in fresh air? • Think about what has just happened after the power stroke: is the piston at the top or bottom of its travel, and what must happen next to prepare for the next cycle?

✅ Before You Answer

• Verify what occurs immediately after the power stroke in the standard four-stroke sequence. • Check which stroke involves exhaust valves open and where the piston is moving at that moment. • Confirm which choice correctly describes both the piston direction (up or down) and the process (intake, compression, power, or exhaust) for that next stroke.