MDE 1 End of Unit Quiz

MDE 1 End Of Unit Quiz

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1. Purpose of the Compression Stroke

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

B) To ignite the air-fuel mixture

C) To compress the air in the cylinder

D) To draw fresh air into the cylinder

A) To expel exhaust gases from the cylinder

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6. Starting Systems

Question: Which of the following methods is commonly used to start a large marine diesel engine?

C) Hydraulic start

A) Electric starter motor

B) Compressed air start

D) Manual crank start

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5. Timing of Fuel Injection

Question: When is fuel typically injected into the cylinder of a marine diesel engine?

B) At the beginning of the compression stroke

A) During the intake stroke

C) At the end of the compression stroke

D) During the exhaust stroke

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5. Pressure Changes During Exhaust Stroke

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

B) It remains constant

C) It decreases as the piston moves upward

D) It fluctuates randomly

A) It increases significantly

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6. Compression Ratio in Diesel Engines

Question: Why is the compression ratio typically higher in diesel engines compared to gasoline engines?

B) To improve fuel atomization

A) To increase engine speed

D) To reduce engine noise

C) To ensure the air is hot enough to ignite the fuel

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1. Combustion in Marine Diesel Engines

Question: What is the main purpose of the turbocharger in a marine diesel engine?

B) To increase the engine’s air intake pressure

D) To lubricate the engine’s moving parts

C) To reduce the engine’s fuel consumption

A) To cool the engine’s exhaust gases

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10. Supercharging

Question: Which of the following is a benefit of supercharging in a marine diesel engine?

B) Increased engine efficiency and power output

A) Reduced engine weight

D) Improved fuel quality

C) Lower exhaust emissions

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9. Scavenge Systems

Question: What is the purpose of the scavenging system in a two-stroke marine diesel engine?

A) To increase fuel injection pressure

D) To lubricate the piston rings

B) To remove exhaust gases and fill the cylinder with fresh air

C) To cool the cylinder head

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4. Effect on Air Temperature During Compression Stroke

Question: What happens to the temperature of the air inside the cylinder during the compression stroke in a marine diesel engine?

D) It fluctuates

C) It increases

A) It decreases

B) It remains the same

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Transfer of Gas Force from Piston Crown to Crankshaft

Question: How is the force generated by the combustion gases transferred from the piston crown to the crankshaft in a four-stroke diesel engine?

C) Via the camshaft which then drives the crankshaft

B) Directly through the piston rings which transfer force to the crankshaft

D) Through the exhaust valves which push the crankshaft

A) Through the connecting rod which converts the linear motion of the piston into rotational motion

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5. Timing of the Intake Stroke

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

A) Immediately after the compression stroke

C) Immediately after the exhaust stroke

D) Immediately after the intake valve closes

B) Immediately after the power stroke

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8. Intake Stroke in Diesel vs. Gasoline Engines

Question: How does the intake stroke in a marine diesel engine differ from that in a gasoline engine?

C) Both engines intake an air-fuel mixture

A) Diesel engines intake pure air, while gasoline engines intake an air-fuel mixture

B) Diesel engines intake an air-fuel mixture, while gasoline engines intake pure air

D) Both engines intake pure air

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