MDE 11 End of Unit Quiz

Correct Answer: B) To separate water from fuel by causing small water droplets to combine into larger droplets.

Explanation:
The primary function of a coalescer type filter is to separate water from fuel. It works by causing small water droplets dispersed in the fuel to coalesce (combine) into larger droplets, which can then be easily separated from the fuel. This is essential in preventing water contamination in the fuel, which can cause corrosion and other operational issues in a diesel engine.

Correct Answer: D) The oil’s contamination level

Explanation: The contamination level of the oil directly affects how often the purifier needs to discharge. High contamination levels will require more frequent discharges to ensure the oil remains clean.

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.

• 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: B) By regularly testing the oil's viscosity, water content, and acid number
Explanation: Regular testing of the oil's physical and chemical properties is essential to monitor its condition and determine if it remains effective.

Correct Answer: C) A leaking cylinder head gasket

Explanation: A leaking cylinder head gasket can allow coolant or water to mix with the engine oil, leading to contamination.

Correct Answer: B) By conducting a crackle test
Explanation: The crackle test involves heating a small amount of oil to check for the presence of water, indicated by crackling or popping sounds as the water evaporates.

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: C) By using a series of filter media that cause small water droplets to merge into larger droplets, which are then easily separated.

Explanation:
Coalescer filters use specialized filter media designed to coalesce, or combine, small water droplets in the fuel into larger droplets. Once the water droplets are large enough, they can be separated from the fuel more easily, typically settling out and being removed via a water separator.

Correct Answer: A) By preventing oil leakage through seal and joint failures

Explanation: Proper sealing and joint integrity prevent oil from leaking out of the separator, thus minimizing oil losses.

Correct Answer: B) To remove water and particulate contaminants from the oil
Explanation: The centrifugal separator is designed to remove contaminants such as water, sludge, and other particles from the lubricating oil, ensuring it stays in optimum condition.

Correct Answer: B) Ensuring proper engine warm-up before operation

Explanation: Properly warming up the engine ensures that it reaches operating temperature, reducing the risk of condensation and water contamination in the oil.