--- title: "Diesel fuel supply and lubrication functions" subject: "Power Plant Equipment" chapter: 5 key: "semester_7/power_plant_equipment:diesel-fuel-supply-lubrication" source: https://www.bctengineer.com/q/semester_7/power_plant_equipment/diesel-fuel-supply-lubrication site: BCT Engineering --- # Diesel fuel supply and lubrication functions Power Plant Equipment · Chapter 5: Diesel Power Plant - Asked in: 2082 Baisakh, 5+3 marks - Video: [Diesel Power Plant || working and layout || Diesel Engine](https://www.youtube.com/watch?v=ly9CI9nXaC8) — Aeran Classes - 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-lubrication - Whole chapter: https://www.bctengineer.com/md/semester_7/power_plant_equipment/chapter-5 ## Question Explain the fuel supply of a diesel power plant with a neat diagram. State the main functions of lubricating system in a diesel power plant. ## Short answer Fuel flows from storage tank through transfer pump and strainer to day tank, then fine filter, booster pump, injection pump (100–200 bar), and injectors; surplus returns to day tank. Lubrication reduces friction and wear, cools pistons and bearings, seals rings, cleans via filter, and prevents corrosion and noise. ## Answer #### Fuel supply system The fuel supply system stores, cleans and delivers fuel to the engine in the correct quantity, at high pressure and at the right time. ```text Tanker -> unloading pump -> Storage tank | transfer pump + strainer | Day tank | fine filter | booster (fuel) pump | fuel injection pump | injectors -> cylinders (surplus fuel returns to the day tank) ``` 1. **Storage tank:** holds bulk fuel (about a month's need). 2. **Transfer pump and strainer:** send coarse-filtered fuel to the day tank. 3. **Day tank:** small tank holding a few hours' supply near the engine. 4. **Fine filter:** removes dirt and water that would block injector nozzles. 5. **Booster pump:** feeds the injection pump at low pressure. 6. **Fuel injection pump:** raises pressure to about 100–200 bar and meters fuel as set by the governor. 7. **Injector:** atomises fuel into the hot compressed air, where it ignites by itself. Injection arrangements: common rail, individual pump (most common), and distributor systems. #### Main functions of the lubricating system - Reduce friction and wear between moving parts (piston, rings, bearings, cams). - Cool pistons and bearings by carrying heat to the oil cooler. - Seal piston rings against the liner to keep compression. - Clean parts by carrying carbon and metal particles to the filter. - Prevent corrosion and reduce noise. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Which sequence correctly shows the fuel supply? A. Storage - transfer pump/strainer - day tank - fine filter - booster pump - injection pump - injectors B. Injectors - day tank - storage C. Booster pump - storage - injection pump - day tank D. Day tank - injectors - fine filter - storage Answer: A. Fuel is stored, transferred, filtered, pressurised and finally injected. (Key point: Fuel path order) 2. What does the injection pump do that the booster pump does not? A. Raises pressure to about 100-200 bar and meters fuel as set by the governor B. Feeds at low pressure C. Filters water D. Unloads tankers Answer: A. The booster pump only supplies low-pressure fuel; the injection pump develops injection pressure and meters quantity. (Key point: Injection pump function) 3. Which injection arrangement is most common? A. Common rail B. Individual pump for each cylinder C. Distributor D. Gravity feed Answer: B. The answer states the individual pump system is the most common arrangement. (Key point: Injection arrangement) 4. Which list gives main functions of the lubricating system? A. Reduce friction/wear, cool, seal rings, clean, prevent corrosion B. Raise fuel pressure, start the engine, cool exhaust C. Filter air, silence noise only, govern speed D. Increase compression temperature Answer: A. Lubricating oil reduces friction, carries heat, seals piston rings, carries away particles and protects against corrosion. 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