You are assigned to an OSV fitted with main...

You are assigned to an OSV fitted with main...

Question 1 of 2921866636eef28f7522a1c51f712

You are assigned to an OSV fitted with main propulsion diesel engines operating on the cycle represented in the polar timing diagram shown in the illustration. In consideration of the direction of rotation, what combustion cycle event occurs from point "A" to point "D"? Illustration MO-0084

Question 1 of 29218

Q

You are assigned to an OSV fitted with main propulsion diesel engines operating on the cycle represented in the polar timing diagram shown in the illustration. In consideration of the direction of rotation, what combustion cycle event occurs from point "A" to point "D"? Illustration MO-0084

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🔍 Key Concepts

• Four-stroke diesel cycle strokes: intake, compression, power, exhaust • How to read a polar valve timing diagram: direction of rotation, TDC/BDC, and valve-open arcs • Relationship between which valves are open/closed and the name of the stroke

💭 Think About

• From point A to point D, is the piston moving from TDC toward BDC, or from BDC toward TDC according to the rotation arrow? • Looking at the shaded bands, between A and D is the engine on the stroke where the intake valve is open, or the exhaust valve is open, or are both valves closed? • For that part of crank rotation, which one four-stroke event matches that combination of piston movement and valve condition?

✅ Before You Answer

• Verify the crank is rotating in the same direction as the arrow shown on the diagram when you move from A to D • Identify clearly whether the piston is above or below BDC at A and at D • Match the valve condition (intake open / exhaust open / both closed) between A and D to the correct named stroke: intake, compression, power, or exhaust