Question 14 3AE01 - Third Assistant Engineer

The Correct Answer is B **Explanation for Option B (piston rings):** The terms "Barrel face," "Taper face," "Grooved," and "Chrome plated" are specific descriptive characteristics used to classify the design, shape, and coating of **diesel engine piston rings**. * **Barrel face** and **Taper face** describe the running surface profile of compression rings (designed to aid seating or oil control). * **Grooved** often refers to the shape of an oil control ring (slotted or grooved to scrape oil). * **Chrome plated** refers to a hard, wear-resistant coating applied to the face of the ring to prolong its life and reduce cylinder wear, especially crucial in heavy-duty diesel applications. **Explanation for Other Options:** * **A) pistons:** While pistons use these rings, the piston itself is typically described by terms like "Trunk," "Crosshead," "Articulated," or by material (e.g., "Aluminum alloy," "Cast iron"), not by the facial profiles listed. * **C) piston skirts:** The skirt is the lower, guiding portion of the piston. Its primary description relates to its shape (e.g., "Full skirt," "Slipper skirt") or whether it's coated (e.g., "Teflon coated"), but not by barrel or taper face profiles, which are unique to the ring face geometry. * **D) cylinder liners:** Cylinder liners (or sleeves) are described by their material (e.g., "Cast iron," "Nickel carbide coated") or cooling method (e.g., "Wet liner," "Dry liner"). They are the surface the rings rub against, but they do not possess the "barrel face" or "taper face" geometry that describes the contact surface of the ring itself.