Question 24 DDE04 - Designated Duty Engineer - 1000-4000 HP

The Correct Answer is D **Explanation for Option D (4) being correct:** Option D, representing Figure 4, illustrates a **Distributor Pump** (specifically, a Rotary Plunger Distributor pump, like a Bosch VE type). The question explicitly states that the diesel engine is fitted with a **rotary plunger distributor type pump**. Figure 4 is the visual representation of this type of pump, which uses a single metering/pumping plunger and distributes high-pressure fuel sequentially to all cylinders via a rotary motion. This matches the description given in the prompt exactly. **Explanation for why the other options are incorrect:** * **Option A (1):** Figure 1 typically illustrates an **Individual Pump** or **Unit Injector System (UIS)**, where the pump and injector are combined into a single unit actuated by the camshaft (often found in newer high-speed engines). This is not a centralized rotary plunger distributor pump. * **Option B (2):** Figure 2 typically illustrates a **Jerk Pump** or **Inline Pump** system. In this system, there is a separate pumping element (plunger and barrel) for each cylinder, all contained within one housing and actuated by a common camshaft. This is a common type of pump for marine and older heavy-duty applications, but it is not a *rotary plunger distributor* pump. * **Option C (3):** Figure 3 typically illustrates a **Common Rail (CR)** system. This system uses a high-pressure pump to continuously pressurize a common rail (accumulator), and solenoid or piezo injectors are used to deliver fuel based on an electronic control unit (ECU). While advanced harbor tugs might use this, the pump itself is a high-pressure continuous pump, not the specific mechanical *rotary plunger distributor* type described.