MDE 4 End of Unit Quiz

MDE 4 End Of Unit Quiz

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2. Possible Cause: Turbocharger Failure

Question: What could be a reason for a reduction in boost pressure over time in a turbocharged engine?

C) An incorrect engine timing setting

A) A malfunctioning turbocharger or worn turbine blades

B) A faulty ignition system

D) A malfunctioning air conditioning system

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Purpose of Vent Cocks in Air Coolers

Question: What is the purpose of vent cocks in air coolers?

A) To allow the release of trapped air or gases from the cooling system

B) To adjust the temperature of the air before it enters the engine

D) To monitor the coolant level in the air cooler

C) To increase the pressure of the air within the cooler

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1. Purpose of Air Coolers After Turbochargers

Question: Why are air coolers (intercoolers) typically fitted after the main engine turbochargers?

D) To eliminate moisture from the intake air and prevent engine corrosion

B) To decrease the temperature of the intake air, increasing its density and improving engine efficiency

C) To reduce the engine's overall weight and improve its fuel efficiency

A) To increase the temperature of the intake air for better combustion

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Purpose of Zinc Anodes in Air Coolers

Question: What is the purpose of zinc anodes in air coolers?

C) To increase the pressure of the air passing through the cooler

A) To enhance the cooling efficiency of the air cooler

D) To reduce the noise generated by the air cooler

B) To prevent corrosion by providing a sacrificial material that corrodes instead of the cooler components

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Purpose of Labyrinth Glands in Turbochargers

Question: What is the primary purpose of labyrinth glands in the construction of a diesel engine turbocharger?

D) To increase the intake air pressure before it reaches the compressor wheel

B) To prevent the leakage of lubricating oil and seal the gap between the rotating shaft and stationary components

C) To cool the turbocharger by circulating coolant around the bearings

A) To provide additional lubrication to the turbocharger bearings

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5. Effect of Pulse System on Exhaust Temperature

Question: How does a pulse system typically affect the exhaust temperature in a turbocharged diesel engine?

A) It significantly lowers the exhaust temperature by reducing exhaust gas pressure

B) It has no impact on the exhaust temperature

D) It drastically reduces exhaust temperature to prevent turbocharger overheating

C) It may increase exhaust temperature by optimizing the utilization of exhaust gases

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5. Faulty Wastegate or Boost Control Valve

Question: What routine maintenance can be performed to address a faulty wastegate or boost control valve?

D) Change the engine coolant

A) Inspect and clean the wastegate and boost control valve, and check for proper operation

C) Adjust the engine's air-fuel ratio

B) Replace the wastegate or boost control valve with a new one

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Location of Thrust Bearing in Turbochargers

Question: Where is the thrust bearing typically fitted in a large medium-speed diesel engine turbocharger?

C) On the shaft between the compressor side and the bearing housing

D) At the intake manifold to reduce air pressure fluctuations

B) On the exhaust manifold to support the turbocharger housing

A) Between the compressor wheel and the turbine wheel

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1. Advantages of Pulse Systems

Question: What is one of the main advantages of using a pulse system in a turbocharged diesel engine?

B) It enhances the efficiency of the turbocharger by improving turbine response and reducing turbo lag

A) It reduces the overall weight of the turbocharger

D) It simplifies the engine's fuel injection system

C) It eliminates the need for a separate intercooler

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Pulse System in Turbochargers

Question: What is meant by the term "pulse system" in the context of large medium-speed diesel engine turbochargers?

B) A system that utilizes a series of exhaust gas pulses to improve the efficiency of the turbocharger by enhancing turbine response and performance

A) A system that uses multiple turbochargers operating in sequence to boost overall engine power

D) A system designed to reduce the noise generated by the turbocharger during operation

C) A system that measures and adjusts the pulse frequency of the engine's fuel injection to optimize combustion

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Indications of Poor Turbocharger Performance

Question: What are possible indications of poor turbocharger performance? (Select FOUR)

E) Decreased engine coolant temperature

B) Excessive exhaust smoke or black smoke from the engine

A) Increased turbo lag and delayed acceleration

C) Higher engine oil temperature than usual

D) Unusual whining or rattling noises from the turbocharger

F) Reduced power output and overall engine performance

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3. Impact on Engine Performance

Question: How does a turbocharger affect the performance of a diesel engine?

B) It increases the engine's power output by compressing more air into the cylinders

D) It slows down the engine's RPM by increasing the exhaust back pressure

A) It reduces the engine's power output by restricting airflow

C) It decreases the engine's fuel consumption by burning less fuel

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