Fuel system injection for gasoline and diesel

Fuel system lecturer

1. FUEL SYSTEM

Along the discussion please make a list of
requirements to fuel system

2. Pureness of the fuel

« High pressure pump and injectors
¢ Unit injectors
« Electronic unit injectors

Contaminated fuel ruins the fine components

3. Sulphur

+ Converted to sulphur trioxide during
combustion

+ But react with liquid water. The result is
H,SO, — highly corrosive agent

+ React with Zn — White cloud of Zink
sulphate

4. Water

+ Wears fuel system

« Filter media go to swell cutting off the
engine fuel supply

* React with sulphur — H,SO,

5. Steps to overcome effects of
water
+ Drain water from fuel tanks

« Obtain fuel from reliable sources

+ Use water separators

6. Water separators

+ Sediment type

BAFFLE TYPE WATER SEPARATOR

Water and
Sediment Mr >>.
Drain hh— 87 — Water

7. Water separators

* Coalescing type

8. Catalytic Fines

+ Small , hard particles which originate at the
refinery.

+ Cause very rapid abrasive wear on injection
pumps, Piston rings and cylinder liners

« Centrifuging and filtration

9. Micro organisms in Fuel

* Cause corrosion and filter plugging

« Bioside added to the fuel will kill them but
not remove the remained of their bodies

« Clean tanks and filter the fuel

10. .

.

Steps to minimize problem

Avoid long fuel storage periods
Drain water from fuel tanks regularly
Purchase fuel from reliable sources

Dose all fuel inventory with biocide at the
first sign of micro organism contamination

11. Filters

+ Primary Fuel Strainer — 0.1x 0.2 mm

« Secondary Fuel Filter — 10 microns

Advised by engine manufacturer

12. Air in the fuel line

Interruption of the flow

13. Heat in the fuel

Power loss 1% of each 6 °C (10 ° F) above
29° C (85 ° F)

14. Fuel Coolers
Factors affect the need for fuel cooling equipment:

Length of periods of continuous operation
Length of time between periods of operation
Volume of the fuel tank (larger than 11000L)

Ability of the fuel tanks to dissipate the heat of
stored fuel

15. REQUIREMENTS

Pureness of the fuel

No air in the fuel line

No excessive heat in the fuel

As less restriction in the line as possible
Storage

If more then one tank — transfer

Stop flow when engine stop

How much fuel available

Isolating branch in case of contaminating

16. e

Fuel tanks

Size

How many tanks

Location

Materials

Requirements to the tank arrangement

17. Size

« Fuel consumption

f x hp (of kW)
Fan

Sx 1000
S - Specific gravity of diesel fuel — 0.83

f - Specific fuel consumption: g/hp-hr or g/kW-hr
F - Fuel consumption: l/hr

+ Proposed hours work without refill

18. e

How many tanks?

One — small boats

Two - Starboard and Port — stability
maintenance

More than two
Day tank

19. Day tanks
Factors affect the need for fuel cooling equipment:

Length of periods of continuous operation
Length of time between periods of operation
Volume of the fuel tank ( larger than 11000L)

Ability of the fuel tanks to dissipate the heat of
stored fuel

20. Location of the day tank

« The level of the fuel is to be no higher than
the fuel injection valves on the engine
« Close enough to the engine so the total

suction lift is less than the suction head of
the fuel pump.

21. Location

+ On the bottom or close to the hull side provides
good cooling but could create too great stability

+ Close to the engine provide small resistance of the
lines but weight distribution could suffer

+ Level —

1.Lower than engine injectors or

shut off valve to be provided -

solenoid or manual;

2.No lower than suction head of the fuel
pump or transfer to additional higher
tank is to be provided

22. Materials

« Sheet steel

« Marine aluminium
+ Nickel-copper

« Fibreglass

Polyethylene

Galvanized material should never be used
Cu react with the sulphur in diesel as well

23. Requirements to the tank

Fill

Ventilation

Gauge

Drain

Cleaning access
Discharge line
Return line

Baffles
Grounding/Bonding

24. Tank construction

Suetion Line ia na

Vent Line

25. Tank arrangement

Vent Cap - Locate Away
From Flame or Sparks

Engine to Tank
(Return Line)

Aux. Tank to Main

Tank Line
Hones (Overtiow Line)
Level
Sight
clas Pump Control
| — Float Switch

Auxiliary Fuel | Cleaning Access

Pump

Sediment and
Water Trap
Valve

T | Tönkto Engine
(Delivery Line)

Main Tank to

Aux. Tank

(Fill Line)

Drain Valve

26. Fuel return line

« Pressure limit — acc. manufacturer
« Size at least same size as a supply line
¢ A shutoff valve is not recommended

27. Test

+ 3 psi or more depends of rules complied

Clean and flush fuel system prior to start the
engine