Diesel fuel supply and lubrication functions

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.

 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.