MDE Flash Cards Unit 1 Four Strokes Flashcards

MDE Unit 1 four strokes

6. Compression Ratio in Diesel Engines

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

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

5. Timing of Fuel Injection

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

C) At the end of the compression stroke

6. Starting Systems

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

B) Compressed air start

1. Purpose of the Intake Stroke

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

C) To draw fresh air into the cylinder

2. Valve Operation During Exhaust Stroke

Question: During the exhaust stroke of a four-stroke marine diesel engine, which valve is open?

B) Exhaust valve

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?

C) It generates the force needed to produce mechanical work

9. Scavenge Systems

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

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

7. Engine Governors

Question: What is the primary function of the governor in a marine diesel engine?

B) To control the engine’s speed

1. Purpose of the Exhaust Stroke

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

C) To expel combustion gases from the cylinder

7. Role of the Compression Stroke in Power Output

Question: How does the compression stroke affect the power output of a marine diesel engine?

C) It prepares the air for combustion, indirectly contributing to power output

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?

C) It increases

7. Potential Issues During Exhaust Stroke

Question: What could happen if the exhaust valve fails to open properly during the exhaust stroke of a marine diesel engine?

C) The combustion gases will remain in the cylinder, causing poor performance

Compression Ratio in Fuel Combustion

Question: What does the term "compression ratio" refer to in the context of fuel combustion in a marine diesel engine?

C) The ratio of the maximum to the minimum volume of the combustion chamber during the engine cycle

2. Valve Operation During Intake Stroke

Question: During the intake stroke of a four-stroke marine diesel engine, which valve is open?

B) Intake valve

10. Supercharging

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

B) Increased engine efficiency and power output

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?

C) It increases

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?

C) It decreases as the piston moves upward

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?

A) Chemical energy from the fuel

2. Cooling Systems

Question: What is the most likely cause of an increase in jacket water temperature in a marine diesel engine?

C) Insufficient coolant circulation

4. Fuel Injection Systems

Question: In a marine diesel engine, what is the purpose of the fuel injector?

C) To atomize the fuel and inject it into the combustion chamber

Components in a Cross-Section of a Four-Stroke Diesel Engine Piston

Question: In a cross-section view of a four-stroke diesel engine piston, which of the following components are typically visible?

A) Piston crown, piston rings, and piston skirt

Factors Influencing Atomization

Question: Which of the following factors influence the atomization of fuel in a marine diesel engine?

A) Fuel temperature and injection pressure

1. Purpose of the Compression Stroke

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

C) To compress the air in the cylinder

7. Significance of the Intake Stroke

Question: Why is the intake stroke crucial for the operation of a four-stroke marine diesel engine?

B) It ensures the cylinder is filled with a fresh charge of air for combustion

7. Role of the Compression Stroke in Power Output

Question: How does the compression stroke affect the power output of a marine diesel engine?

C) It prepares the air for combustion, indirectly contributing to power output

Atomization in Fuel Combustion

Question: What is meant by the term "atomization" in the context of fuel combustion in a marine diesel engine?

B) The conversion of fuel into fine droplets to enhance combustion efficiency

2. Valve Operation During Compression Stroke

Question: During the compression stroke of a four-stroke marine diesel engine, which valves are closed?

A) Both intake and exhaust valves

3. Piston Movement During Exhaust Stroke

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

A) Upward toward the cylinder head

1. Purpose of the Compression Stroke

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

C) To compress the air in the cylinder

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?

B) Downward away from the cylinder head

4. Combustion Process in Power Stroke

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

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

6. Exhaust Stroke and Engine Efficiency

Question: How does the exhaust stroke impact the overall efficiency of a marine diesel engine?

D) It maintains efficiency by ensuring complete removal of exhaust gases

8. Exhaust System in Diesel Engines

Question: What is the role of the exhaust system connected to the cylinder during the exhaust stroke?

C) It channels the exhaust gases out of the engine

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?

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

6. Timing of the Power Stroke

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

C) Immediately after the compression stroke

3. Valve Operation During Power Stroke

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

D) Both valves are closed

3. Lubrication Systems

Question: Which of the following is the primary function of a lubricating oil system in a marine diesel engine?

C) To reduce friction between moving parts

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

Factors Influencing Compression Ratio

Question: Which of the following factors primarily influence the compression ratio in a marine diesel engine?

A) Cylinder volume and piston design

6. Compression Ratio in Diesel Engines

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

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

8. Common Issues During Compression Stroke

Question: What could be a possible cause of reduced compression in a marine diesel engine?

C) Worn piston rings or cylinder liner

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?

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

5. Exhaust Systems

Question: What is the primary purpose of the exhaust valve in a marine diesel engine?

A) To release burned gases from the combustion chamber

Factors Influencing Penetration

Question: Which of the following factors primarily influence the penetration of fuel in the combustion chamber of a marine diesel engine?

A) Fuel temperature and injector nozzle design

Penetration in Fuel Combustion

Question: What does the term "penetration" refer to in the context of fuel combustion in a marine diesel engine?

B) The distance fuel droplets travel into the combustion chamber before igniting

4. Timing of the Exhaust Stroke

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

B) Immediately after the power stroke

4. Air-Fuel Mixture in Intake Stroke

Question: What is drawn into the cylinder during the intake stroke in a marine diesel engine?

C) Pure air

8. Common Issues During Compression Stroke

Question: What could be a possible cause of reduced compression in a marine diesel engine?

C) Worn piston rings or cylinder liner

3. Piston Movement in Intake Stroke

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

B) Downward away from the cylinder head

6. Pressure in the Cylinder During Intake

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

B) It decreases slightly

Working Principle of the Four-Stroke Cycle

Question: Which of the following correctly describes the working principle of the four-stroke cycle in a marine diesel engine?

C) Intake, Compression, Power, Exhaust

8. Fuel Systems

Question: Which of the following is a common cause of fuel injection pump failure in marine diesel engines?

B) Contaminated fuel

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?

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

2. Valve Operation During Compression Stroke

Question: During the compression stroke of a four-stroke marine diesel engine, which valves are closed?

A) Both intake and exhaust valves

3. Piston Movement in Compression Stroke

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

B) Upward toward the cylinder head

3. Piston Movement in Compression Stroke

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

B) Upward toward the cylinder head

5. Timing of the Intake Stroke

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

C) Immediately after the exhaust stroke

5. Timing of Fuel Injection

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

C) At the end of the compression stroke

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

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