--- title: "Fuel supply system of diesel plant" subject: "Power Plant Equipment" chapter: 5 key: "semester_7/power_plant_equipment:diesel-fuel-supply" source: https://www.bctengineer.com/q/semester_7/power_plant_equipment/diesel-fuel-supply site: BCT Engineering --- # Fuel supply system of diesel plant Power Plant Equipment · Chapter 5: Diesel Power Plant - Asked in: 2074 Asoj, 8 marks; 2071 Shrawan, 6 marks (asked 2 times) - Video: [Diesel - 5 | Fuel Storage & Supply System, Need | Suction & Transfer type, Schematic diagram | Hindi](https://www.youtube.com/watch?v=QVQIMS48TbY) — Origin's e-Shala - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/power_plant_equipment/diesel-fuel-supply - Whole chapter: https://www.bctengineer.com/md/semester_7/power_plant_equipment/chapter-5 ## Question Explain the fuel supply system of a diesel power plant with neat diagram. ## Short answer Fuel flows from storage tanks through a strainer to a day tank, then through fine filters and a booster pump to the injection pump. The injection pump meters high-pressure fuel and injectors atomize it into the cylinders at the correct time. ## Answer The **fuel supply system** of a diesel power plant receives, stores, cleans and delivers fuel oil to the engine cylinders in the right quantity, at high pressure and at the correct time. ```text Tanker/rail -> unloading pump -> Main storage tanks | transfer pump | filter (strainer) | Day tank | fine filter | fuel (booster) pump | fuel injection pump (high pressure, metered) | injectors -> engine cylinders ``` #### Components 1. **Storage tanks:** large tanks (above or below ground) holding about a month's fuel, filled from tankers through unloading pumps and strainers. 2. **Transfer pump and strainer:** move fuel from storage to the day tank after coarse filtering. 3. **Day tank:** small tank near the engine, holding about 8 hours' supply; often placed high so fuel flows by gravity. 4. **Fine filters:** remove dirt and water; dirty fuel blocks injector holes and wears pump plungers. 5. **Fuel (booster) pump:** feeds fuel to the injection pump at low pressure. 6. **Fuel injection pump:** plunger-type pump that raises pressure to about 100–200 bar (much higher in modern engines) and meters exact quantity per cycle as set by the governor. 7. **Injectors (atomisers):** spray fine fuel droplets into hot compressed air in the cylinder at the end of the compression stroke; the fuel ignites by itself. 8. **Heaters** (for heavy oil) and return lines from injectors back to the day tank. #### Types of fuel injection systems - **Common rail system:** one high-pressure pump keeps a common header at constant pressure; injectors open by timing. - **Individual pump system:** separate pump for each cylinder; most common. - **Distributor system:** one pump meters fuel and a distributor sends it to each cylinder in turn. #### Requirements - Accurate metering and timing; fine atomisation; quick start and stop of injection without dribble. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is the function of the day tank? A. Small tank near the engine holding about 8 hours' supply, often placed high for gravity flow B. Main bulk storage for a month's fuel C. Raises fuel pressure to 200 bar D. Atomises fuel in the cylinder Answer: A. Fuel is moved from storage to the day tank close to the engine to feed the system. (Key point: Purpose of day tank) 2. What does the fuel injection pump do? A. Unloads fuel from tankers B. Raises pressure (about 100-200 bar) and meters the exact quantity per cycle C. Cools the fuel D. Burns fuel before injection Answer: B. A plunger pump delivers high-pressure, metered fuel as set by the governor. (Key point: Role of injection pump) 3. Why are fine filters used before the injection pump? A. To raise the calorific value B. Dirt and water would block injector holes and wear pump plungers C. To heat the fuel D. To reduce noise Answer: B. Contaminants damage precision parts such as nozzles and plungers. (Key point: Why fine filters) 4. How does fuel ignite in a diesel engine? A. A spark plug fires B. Injector sprays fine droplets into hot compressed air near the end of compression, and it self-ignites C. The booster pump heats it D. It ignites in the day tank Answer: B. Compression heats the air enough to ignite atomised fuel, so no spark is needed. (Key point: Injector action) ## Close variants set in other exams - [Diesel plant components and fuel supply](https://www.bctengineer.com/question.md?key=semester_7%2Fpower_plant_equipment%3Adiesel-components-fuel-supply) — Power Plant Equipment, chapter 5, asked 3× ## Related in Power Plant Equipment - [Diesel fuel supply and lubrication functions](https://www.bctengineer.com/question.md?key=semester_7%2Fpower_plant_equipment%3Adiesel-fuel-supply-lubrication) — Power Plant Equipment, chapter 5 - [Diesel layout, starting and fuel supply systems](https://www.bctengineer.com/question.md?key=semester_7%2Fpower_plant_equipment%3Adiesel-layout-starting-fuel) — Power Plant Equipment, chapter 5 - [Diesel fuel storage, supply and applications](https://www.bctengineer.com/question.md?key=semester_7%2Fpower_plant_equipment%3Adiesel-fuel-storage-applications) — Power Plant Equipment, chapter 5 - [Layout of diesel power plant](https://www.bctengineer.com/question.md?key=semester_7%2Fpower_plant_equipment%3Adiesel-plant-layout) — Power Plant Equipment, chapter 5, asked 3× - [Diesel engine 75 kW: fuel consumption and efficiencies](https://www.bctengineer.com/question.md?key=semester_7%2Fpower_plant_equipment%3Adiesel-75kw-fuel-consumption) — Power Plant Equipment, chapter 5 - [Diesel plant lubrication and cooling systems](https://www.bctengineer.com/question.md?key=semester_7%2Fpower_plant_equipment%3Adiesel-lubrication-cooling) — Power Plant Equipment, chapter 5, asked 2× ## Related in other subjects - [Types of power supply system for industrial plant](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aindustrial-supply-system-types) — Industrial Power Distribution and Illumination, chapter 1, asked 2× - [Load duration curve; diesel plant; ROR flow duration](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Aload-duration-diesel-import-fdc) — Hydropower Engineering, chapter 3 - [Emergency power supply system for industry](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aemergency-supply-system-industry) — Industrial Power Distribution and Illumination, chapter 9, asked 2× - [Short note: Power supply system](https://www.bctengineer.com/question.md?key=semester_1%2Fbasic_electrical_and_electronics_engineering%3Ashort-note-power-supply-system) — Basic Electrical and Electronics Engineering, chapter 4