MDE 3 End of Unit Quiz

MDE 3 End Of Unit Quiz

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Effects of Loss of Timing Drive Tension

Question: How does a loss of tension in engine timing belts or chains affect the engine?

B) It can lead to incorrect valve timing, causing engine misfires and potential damage

D) It enhances the performance of the turbocharger

C) It increases the engine's horsepower output

A) It improves fuel efficiency by reducing friction

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Meaning and Purpose of Valve Overlap

Question: What does the term "valve overlap" refer to, and what is its purpose in an engine?

D) Valve overlap refers to the time when only the exhaust valve is open. Its purpose is to decrease the engine's fuel consumption.

B) Valve overlap refers to the period when both the intake and exhaust valves are open simultaneously. Its purpose is to enhance the engine’s performance by improving the scavenging of exhaust gases and increasing the intake of fresh air.

C) Valve overlap refers to the period when the intake valve opens before the exhaust valve closes. Its purpose is to reduce engine noise and vibration.

A) Valve overlap refers to the period when both the intake and exhaust valves are closed to maximize compression. Its purpose is to prevent exhaust gases from entering the intake manifold.

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5. Timing Chain Tensioner Function

Question: What is the role of the timing chain tensioner in the timing chain system?

B) To maintain the correct tension in the timing chain

C) To enhance the engine’s power output

D) To adjust the engine’s idle speed

A) To regulate the engine’s fuel intake

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3. Function of Side Plates in a Timing Chain

Question: What is the function of the side plates in a timing chain?

C) To lubricate the chain links

A) To keep the chain aligned and secure

D) To support the engine’s pistons

B) To adjust the tension of the timing chain

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1. Chain Tension Check

Question: During a drive inspection of a chain-driven camshaft, why is it important to check the chain tension?

B) To verify that the chain is aligned with the crankshaft

C) To prevent excessive wear and noise, and to ensure proper timing

D) To confirm the chain’s color and condition

A) To ensure the chain is properly lubricated

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2. Valve Operation during the Compression Stroke

Question: What is the position of the valves during the compression stroke in a four-stroke engine timing diagram?

A) Both the intake and exhaust valves are open

D) The intake valve is closed, and the exhaust valve is open

C) The intake valve is open, and the exhaust valve is closed

B) The intake valve is closed, and the exhaust valve is closed

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Purpose of Double (Nested) Valve Springs

Question: Why might double (nested) valve springs be fitted in a four-stroke diesel engine?

A) To improve fuel atomization and reduce exhaust emissions

D) To reduce the overall weight of the engine and improve fuel efficiency

B) To increase the engine's compression ratio and power output

C) To prevent valve float at high engine speeds and ensure consistent valve operation

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Effects of Too Large Tappet Clearance

Question: What are the effects of having too large a tappet clearance on the exhaust valves of a four-stroke diesel engine?

B) Poor engine performance, increased valve train wear, and potential for valve damage

A) Increased engine power and improved fuel efficiency

D) Quieter engine operation and reduced oil consumption

C) Enhanced cooling of the engine and reduced exhaust emissions

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Components of a Timing Chain Link

Question: What components are typically found in a timing chain link?

A) Chain links, rollers, and side plates

B) Gears, sprockets, and tensioners

C) Pulleys, belts, and idlers

D) Camshafts, crankshafts, and valves

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5. Timing of Fuel Injection

Question: In a four-stroke timing diagram, when does the fuel valve typically operate?

A) Just before the intake valve closes and the compression stroke begins

B) During the power stroke

D) Just after the exhaust valve opens and before the intake valve opens

C) During the exhaust stroke

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3. Valve Operation during the Power Stroke

Question: In a four-stroke engine timing diagram, what occurs with the valves during the power stroke?

D) The intake valve is closed, and the exhaust valve opens

A) The intake valve opens, and the exhaust valve remains closed

B) Both the intake and exhaust valves are open

C) The intake valve remains closed, and the exhaust valve remains closed

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Effects of Too Small Tappet Clearance

Question: What are the effects of having too small a tappet clearance on the exhaust valves of a four-stroke diesel engine?

B) Overheating of the valves, potential for incomplete valve closure, and increased wear on the valve train

D) Increased power output and better acceleration

C) Enhanced fuel injection timing and reduced engine noise

A) Improved valve sealing and increased engine efficiency

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