MDE 11 End of Unit Quiz

Correct Answer: C) Formation of oil sludge

Explanation: Water in engine oil can cause the formation of sludge, which can impede the flow of oil and affect lubrication.

Correct Answer: B) Regularly replacing the oil filters
Explanation: Regular replacement of oil filters helps in removing contaminants from the oil, thus preventing its deterioration.

These questions cover various aspects of maintaining the lubricating oil in optimum condition in a large medium-speed diesel engine.

Correct Answer:
B) The filter employs a magnetic field to attract and remove ferrous particles from the oil.

Explanation: A magnetic lubricating oil filter operates by using a magnetic field to attract and capture ferrous (iron-based) particles that may be present in the oil, thereby preventing these particles from circulating through the engine and causing wear or damage.

Correct Answer: B) To assess the oil’s ability to neutralize acids
Explanation: The TBN measures the oil's ability to neutralize acidic byproducts from combustion, which is critical to preventing corrosion and maintaining engine health.

Correct Answer: B) A higher flow rate results in higher discharge frequency

Explanation: A higher flow rate means more oil is processed through the purifier in a given time, which can increase the rate at which contaminants build up and thus require more frequent discharges.

• Correct Answer: C) Oil is spun at high speed to separate contaminants based on density

Explanation: The centrifugal filter operates by spinning the oil at high speed within the rotor. This high-speed rotation creates a centrifugal force that causes the denser particles (contaminants) to move outward, separating them from the less dense, cleaner oil. This process is entirely mechanical and relies on the principle of density differences.

• Correct Answer: C) To remove contaminants from the oil by using centrifugal force

Explanation: The primary function of a centrifugal type lubricating oil filter is to remove contaminants such as dirt, metal particles, and other impurities from the lubricating oil. It does this by spinning the oil at high speeds in a rotating bowl or rotor, which generates centrifugal force. This force pushes the denser contaminants to the outer wall of the rotor, separating them from the cleaner oil.

Correct Answer: C) Incomplete separation of contaminants

Explanation: Incomplete separation can lead to oil carryover, where the oil mixed with contaminants exits the separator, causing oil losses.

Correct Answer: C) A damaged water pump

Explanation: A damaged water pump can lead to coolant leakage, which may then mix with the engine oil and cause water contamination.

Correct Answer: B) They are collected in a water separator and drained off.

Explanation:
After the water droplets coalesce into larger droplets, they are separated from the fuel. These larger water droplets are typically collected in a water separator, where they can be drained off to prevent them from entering the engine fuel system, which could cause damage or operational issues.

Correct Answer:
C) The filter uses centrifugal force to separate contaminants from the oil.

Explanation: A centrifugal lubricating oil filter operates by spinning the oil at high speeds, which generates centrifugal force. This force pushes heavier contaminants, such as dirt, metal particles, and sludge, to the outer edges of the filter, effectively separating them from the cleaner oil. The clean oil can then be recirculated back into the engine, while the contaminants remain trapped in the filter.

Correct Answer:
D) The filter causes small droplets of water or other liquids to merge into larger droplets, which are then separated from the oil.

Explanation: A coalescer lubricating oil filter works by using materials that cause small droplets of water or other liquids to coalesce, or merge, into larger droplets. These larger droplets are easier to separate from the oil, allowing them to be removed efficiently, thus purifying the oil from water or other liquid contaminants.