Question 65 3AE01 - Third Assistant Engineer

The Correct Answer is B **Explanation for Option B (slow-speed engine fuel pump):** The component shown is a high-pressure mechanical unit designed for precise metering and pressurization of fuel. In large, low-speed marine diesel engines (like crosshead engines), the fuel pump is a robust, positive-displacement plunger pump that takes fuel oil at supply pressure and raises it to the extremely high pressures (often over 1000 bar) required for injection into the cylinder. Key visual features typically include: 1. A robust block housing to withstand immense pressures. 2. A large plunger assembly actuated by a camshaft. 3. Mechanisms (like a control rack or lever) for precisely controlling the quantity of fuel delivered (by adjusting the spill timing of the plunger), which corresponds directly to engine load and speed. This structure is characteristic of the main fuel pump used in these large engines. **Explanation of Why Other Options are Incorrect:** * **A) slow-speed engine cylinder liner lubricator:** A liner lubricator is a small, specialized unit designed to deliver very small, precisely metered amounts of oil to multiple points on the cylinder liner wall. It typically consists of a bank of small pumps or metering valves, not the single, large, high-pressure pumping unit dedicated to fuel delivery. * **C) centrifugal flyweight governor:** A centrifugal governor is a rotational speed-sensing device. It uses flyweights that move outward as speed increases to mechanically adjust the position of the fuel pump control rack. It looks like a complex linkage and rotating mechanism, not a stationary, block-like high-pressure pump. * **D) injector cooling system pump:** This is a low-pressure circulating pump (often centrifugal or gear type) used to move cooling medium (like water or light oil) through the injector jackets. It would have a motor or drive shaft and large inlet/outlet flanges for flow, lacking the intricate high-pressure plunger and control rack system seen on the fuel pump.