MDE 3 End of Unit Quiz

MDE 3 End Of Unit Quiz

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3. Alignment of the Camshaft and Crankshaft

Question: Why is it important to check the alignment of the camshaft and crankshaft during a drive inspection?

D) To verify the lubrication system’s effectiveness

A) To ensure the engine’s visual appearance

B) To confirm the alignment of the engine's accessories

C) To ensure proper timing and efficient engine operation

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Correcting Slight Loss of Timing Drive Tension

Question: How can slight loss of tension in engine timing belts or chains be corrected?

A) By replacing the timing belt or chain with a new one

D) By adding extra lubrication to the timing components

B) By adjusting the tensioner or idler pulleys to restore proper tension

C) By increasing the engine's operating temperature

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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?

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

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

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

A) To improve fuel atomization and reduce exhaust emissions

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Procedure for Setting Tappet Clearance

Question: What is the correct procedure for setting tappet clearance on diesel engine inlet/exhaust valves?

D) Measure the clearance with the engine cold, adjust the tappets using a feeler gauge, and then recheck the clearance with the engine at top dead center of the compression stroke.

A) Measure the clearance with the engine hot and running, then adjust the tappets by tightening or loosening the screws while the engine is operating.

B) Set the engine to a specific RPM, measure the clearance with the engine off, and then adjust the tappets by removing the rocker cover.

C) Measure the clearance with the engine cold, adjust the tappets with a feeler gauge, and then recheck the clearance with the engine running.

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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?

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

A) Both the intake and exhaust valves are 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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Effects of Loss of Timing Drive Tension

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

A) It improves fuel efficiency by reducing friction

D) It enhances the performance of the turbocharger

C) It increases the engine's horsepower output

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

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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?

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.

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.

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.

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

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6. Timing Chain Guide Purpose

Question: What is the purpose of the timing chain guide?

D) To monitor the engine’s fuel consumption

A) To control the flow of coolant to the engine

B) To guide the timing chain and prevent it from deviating from its path

C) To regulate the engine’s exhaust emissions

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1. Valve Operation during the Intake Stroke

Question: In a four-stroke engine timing diagram, what happens to the intake valve during the intake stroke?

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

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

C) The intake valve is partially open while the exhaust valve is closed

B) The intake valve is open to allow air-fuel mixture into the cylinder

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Four-Stroke Timing Diagram

Question: What does a four-stroke timing diagram illustrate?

A) The sequence of fuel injection and ignition events

B) The synchronization of valve openings and closings with the piston positions during the four-stroke cycle

C) The fuel consumption rate at different engine speeds

D) The temperature variations of the engine during operation

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6. Timing of Valve Openings and Closings

Question: How is the timing of the valve openings and closings shown in a four-stroke timing diagram?

A) As a series of graphs showing fuel consumption rates

C) As numerical values indicating the temperature of the exhaust gases

B) As overlapping lines representing the duration each valve is open or closed relative to the piston position

D) As a sequence of numbers representing engine RPM

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1. Function of Timing Chain Links

Question: What is the primary function of the chain links in a timing chain system?

A) To connect the camshaft to the crankshaft

B) To adjust the timing of the engine

C) To maintain the proper tension in the timing belt

D) To transmit rotational motion between the sprockets

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