MDE 10 Q1

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) Forced circulation lubrication

Explanation: Forced circulation lubrication is a common method used in medium-speed diesel engines. This method uses a pump to circulate oil throughout the engine, ensuring a steady supply to the cylinder liners and other critical components. Splash lubrication is less common in medium-speed engines, which typically use forced circulation for better control and consistency.

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.

Explanation:

• A) Increased friction and wear: Insufficient lubrication causes increased friction between moving parts, leading to overheating and accelerated wear, which can result in engine damage and failure.
• B) Improved engine efficiency: This is incorrect. Insufficient lubrication does not improve engine efficiency. Instead, it increases friction and reduces efficiency.
• C) Decreased oil consumption: This is incorrect. Insufficient lubrication typically leads to increased oil consumption due to the need for additional oil to manage the increased friction and wear.
• D) Enhanced engine performance: This is incorrect. Insufficient lubrication generally degrades engine performance by causing excessive friction, overheating, and potential damage.

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.

B) Oil is splashed onto the cylinder liners by the movement of engine components

Explanation: In splash lubrication, oil is dispersed onto the cylinder liners by the movement of rotating engine components, such as the crankshaft. This method is generally used in smaller engines or older designs, and it relies on the mechanical action to spread oil, which may not be as uniform or controlled as forced circulation.