MDE 10 End of Unit Quiz

Correct Answer: A) To prevent oil degradation and maintain performance over time

Explanation: High oxidation resistance helps prevent the oil from breaking down due to reactions with oxygen. This maintains the oil’s performance and prolongs its useful life, ensuring reliable engine protection.

These questions and answers cover essential properties of lubricating oil, highlighting their importance for engine performance and safety.

Correct Answers: A) Add oil to the gearbox until it reaches the recommended level
D) Regularly check and maintain the oil level

Explanation:

• Add oil to the gearbox until it reaches the recommended level: Adding the appropriate amount of oil directly addresses the issue of insufficient oil level, ensuring proper lubrication and operation.
• Regularly check and maintain the oil level: Regular monitoring and maintenance prevent the oil level from dropping below the recommended amount, helping to avoid future problems.

Note: Installing a larger oil reservoir can be helpful but is not a direct solution to the immediate problem of insufficient oil. Decreasing the operational load or using a different type of lubricant does not address the core issue of the oil level being too low.

Explanation:

• A) Grease can become less effective at high temperatures compared to oil: Correct. Grease can degrade or become less effective at higher temperatures compared to oils, which often have higher temperature tolerances.
• B) Grease requires frequent re-lubrication compared to oil: Incorrect. One advantage of grease is that it generally requires less frequent re-lubrication compared to oil due to its thicker consistency and staying power.
• C) Grease can attract dust and debris, leading to potential contamination: Correct. Grease can attract dust and debris due to its sticky nature, which can lead to contamination of the bearing and reduced lubrication effectiveness.
• D) Grease provides less protection against corrosion compared to oil: Incorrect. Grease often provides good protection against corrosion due to its ability to stay in place and its additives.

Correct Answers: A) Improve ventilation or cooling systems around the gearbox
B) Use high-temperature resistant lubricants
D) Reduce the gearbox's operational speed

Explanation:

• Improve ventilation or cooling systems around the gearbox: Enhancing the ventilation or adding cooling systems can help manage and reduce the temperature around the gearbox.
• Use high-temperature resistant lubricants: Lubricants designed to withstand higher temperatures will perform better under elevated ambient temperatures and prevent overheating.
• Reduce the gearbox's operational speed: Operating the gearbox at a lower speed can reduce friction and heat generation, helping to manage the effects of high ambient temperatures.

Note: Increasing the ambient temperature control systems is not a practical solution since the problem is related to high ambient temperatures rather than controlling or increasing them. Insulating the gearbox would retain heat rather than alleviate the problem.

Correct Answer: B) Regular oil analysis and monitoring

Explanation: Regular oil analysis and monitoring are crucial for detecting contamination early. This allows for timely intervention to prevent engine damage and ensures that the oil remains in a satisfactory condition.

B) Forced circulation lubrication

Explanation: Medium-speed diesel engines typically use forced circulation lubrication to ensure consistent oil delivery and effective cooling. This method is preferred over splash lubrication in these engines due to its ability to provide a more controlled and reliable oil supply.

B) By a mechanical pump that circulates oil through the engine

Explanation: In forced circulation lubrication systems, a mechanical pump is used to circulate oil throughout the engine. This method ensures that oil reaches the cylinder liners and other critical areas consistently, which helps in maintaining proper lubrication and cooling.

B) Ensures more uniform oil distribution and control of oil flow

Explanation: Forced circulation lubrication provides better control and uniform distribution of oil compared to splash lubrication. The use of a pump ensures that oil is delivered precisely where it is needed, including the cylinder liners, which improves lubrication efficiency and engine performance.

Explanation:

• A) Reduces friction between moving parts: Correct. Lubricating oil forms a film between moving parts to reduce friction, which minimizes wear and improves engine efficiency.
• B) Acts as a coolant to lower engine temperatures: Correct. Lubricating oil helps to carry away heat from the engine components, contributing to overall engine cooling.
• C) Cleans the engine by removing contaminants: Correct. Lubricating oil helps to suspend and carry away contaminants such as dirt and metal particles, preventing them from accumulating in the engine.
• D) Enhances fuel combustion efficiency: Incorrect. While lubricating oil affects engine performance, it does not directly enhance fuel combustion efficiency.
• E) Seals gaps between engine components: Incorrect. Lubricating oil does not seal gaps; it primarily reduces friction, cleans, and helps in cooling.
• F) Prevents corrosion and rust on engine parts: Correct. Lubricating oil contains additives that help to protect engine parts from corrosion and rust.

A) Increases oil viscosity and leads to foaming: Incorrect. Water typically reduces oil viscosity and can cause foaming.

B) Promotes corrosion and rust formation on engine components: Correct. Water contamination leads to rust and corrosion.

C) Enhances the oil’s cleaning and dispersant properties: Incorrect. Water does not enhance cleaning properties; it can harm them.

D) Improves the oil’s cooling capacity: Incorrect. Water does not improve oil cooling; it can cause damage.

Explanation:

• A) Increased oil consumption: Excessive lubrication often results in higher oil consumption because surplus oil can leak or be burned off, leading to a need for more frequent topping up.
• B) Reduced friction: This is misleading. While lubrication does reduce friction, excessive lubrication does not necessarily lead to reduced friction; it can cause other issues such as oil foaming.
• C) Increased risk of oil foaming: Excessive lubrication can lead to oil foaming, which decreases the effectiveness of lubrication and can cause engine damage due to poor oil film formation.
• D) Enhanced cooling: This is incorrect. Excessive oil does not necessarily enhance cooling and can actually lead to problems such as oil foaming, which impairs the cooling function.

Correct Answers:
B) Add a biocide to the lubricating oil
D) Monitor the oil condition more frequently

Explanation: When microbial degradation is detected, adding a biocide helps eliminate the microbes, and increased monitoring allows for the early detection of further degradation or issues, helping to prevent engine damage.