MDE 1 Power Stroke

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8. Temperature Changes During Power Stroke

Question: What happens to the temperature inside the cylinder during the power stroke of a four-stroke marine diesel engine?

C) It increases slightly

A) It decreases significantly

D) It starts high and decreases as the piston moves downward

B) It remains constant

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4. Combustion Process in Power Stroke

Question: What initiates the power stroke in a four-stroke marine diesel engine?

D) Opening of the intake valve

C) Spontaneous ignition of the fuel due to high pressure and temperature

B) Ignition of the fuel by a spark plug

A) Compression of the air-fuel mixture

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3. Valve Operation During Power Stroke

Question: Which valves are open during the power stroke of a four-stroke marine diesel engine?

A) Both intake and exhaust valves

B) Only the intake valve

C) Only the exhaust valve

D) Both valves are closed

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6. Timing of the Power Stroke

Question: When does the power stroke occur in the four-stroke cycle of a marine diesel engine?

D) Immediately after the power stroke

A) Immediately after the intake stroke

B) Immediately after the exhaust stroke

C) Immediately after the compression stroke

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2. Piston Movement During Power Stroke

Question: In which direction does the piston move during the power stroke of a four-stroke marine diesel engine?

C) Remains stationary

B) Downward away from the cylinder head

D) Moves sideways within the cylinder

A) Upward toward the cylinder head

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1. Purpose of the Power Stroke

Question: What is the primary purpose of the power stroke in a four-stroke marine diesel engine?

C) To convert the energy from combustion into mechanical work

B) To draw fresh air into the cylinder

A) To compress the air-fuel mixture

D) To expel exhaust gases from the cylinder

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5. Energy Conversion During Power Stroke

Question: What type of energy is primarily converted into mechanical work during the power stroke of a marine diesel engine?

C) Kinetic energy from the moving piston

A) Chemical energy from the fuel

D) Potential energy from the crankshaft

B) Electrical energy from the battery

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7. Role of the Power Stroke in Engine Operation

Question: Why is the power stroke considered the most critical stroke in the operation of a four-stroke marine diesel engine?

A) It removes exhaust gases from the cylinder

B) It introduces fresh air into the cylinder

D) It compresses the air-fuel mixture for combustion

C) It generates the force needed to produce mechanical work

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