This document provides an introduction to fuel systems for tractors and farm machinery. It defines fuel as a substance that produces energy when consumed by an engine. The key components and workings of fuel systems for spark ignition (SI) and compression ignition (diesel) engines are described. For SI engines, the fuel system includes a fuel tank, filter, carburetor and intake manifold. The carburetor mixes air and fuel. For diesel engines, the high-pressure system includes a fuel tank, filter, injection pump and injectors, which supply precisely metered fuel into the combustion chamber. Fuel quality and proper maintenance of filters are discussed as important for optimal system operation.

1. Hello!
My self Kaushal
here to presenting
On
INTRODUCTION OF FUEL
SYSTEM

2. Subject
Field operation & Maintenance of Tractors & Farm
Machinery-I
(FMP-206)
Presented by
KAUSHAL GADARIYA

3.  WHAT IS FUEL ?
 PROPERTIES OF FUEL
 QUALITIES OF DIESEL FUEL
 FUEL TEST
 FUEL SUPPLY SYSTEM IN SI ENGINE
 COMPONENTS OF FUEL SYSTEM IN SI ENGINE
 CARBURETOR
 FUEL SUPPLY SYSTEM IN DIESEL ENGINE
 COMPONENTS OF FUEL SUPPLY SYSTEM OF DIESEL
ENGINE
 PRECAUTION IN HANDLING OF FUEL SYSTEM
CONTENTS

4. WHAT IS FUEL ?
 It is a substance consumed by the engine to
produce energy
 There are some fuel used in I.C engine
a. Petrol
b. Power kerosene
c. High speed diesel oil
d. Low speed diesel oil

5. PROPERTIES OF FUEL
 In compression ignition engines, the fuel is
injected at the end of the compression stroke.
 The air alone compressed to a pressure of about
35 Kg/cm2
 After this compression the temperature is about
600o c.

6. Sr.
no.
Name of
Fuel
A.P.I.
degree
Specific
gravity
Calorific
value
(kcal/kg)
1.
Light diesel oil
(L.D.O)
22 0.920 10300
2.
High speed diesel
oil(HSD)
31 0.820 10550
3. Power kerosine 40 0.827 10850
4. Petrol 63 0.730 11100
Table: Important properties of fuel

7. QUALITY OF FUEL
 The quality of the fuel mainly depends upon the
following properties:
1. Volatility of fuel
2. Calorific value of fuel
3. Ignition quality of fuel

8. a. Calorific value: Amount of heat liberated by combustion
of fuel
b. Ignition quality: Ease to burning the oil in combustion
chamber
c. Volatility of fuel: It has considerable effect on the
performance of the engine by affecting the following
I. Ease of starting the engine
II. Degree of crankcase oil dilution
III. Formation of vapour lock
IV. Accelerating characteristics of the engine
V. Distribution of fuel in multi-cylinder engine

9. QUALITIES OF DIESEL FUEL
 High speed diesel oil (HSD):-
High speed diesel oil is used for high speed
diesel engines. It is lighter than light diesel oil.
 Light diesel oil (LDO):-
Light diesel oil is the main source of fuel for
slow speed engines.
Contd…

10.  For satisfactory operation, the diesel must satisfy the
following requirements;
1) It must ignite readily and burn evenly.
2) It should have a low viscosity so that it can be
atomized from the nozzle holes.
3) It must have some lubrication qualities to operate
the valves and FI pump parts.
4) It should have minimum foreign materials,
otherwise, the engine parts may rapidly wear out.

11.  A few important tests are recommended to
determine the suitability of fuels for an I.C. engine.
1) Gravity test
2) Distillation test
3) Vapour pressure test
4) Sulpher test
5) Carbon residue
6) Colour test
7) Gum test
8) Flash test
FUEL TEST

12. FUEL SUPPLY SYSTEM IN
SI ENGINE

13. Diagram of fuel supply system in SI engine

14. WORKING PRINCIPLE OF FUEL
SYSTEM IN SI ENGINE
 In some spark ignition engine, the fuel tank is placed
above the level of carburettor.
 The fuel flows from the fuel tank to the carburetor under
the action of gravity.
 There are one or two filters between the fuel tank and the
carburetor.
 Carburetor mix the air and fuel at required air-fuel ratio
according to speed and loads of the engine.
contd…

15.  Carburetor supply air-fuel mixture into inlet manifold.
 Inlet manifold distribute air-fuel mixture into different
cylinder uniformly.
 At last the air-fuel mixture injected into the combustion
chamber.
 After combustion of fuel the unwanted exhaust gases flow
out through exhaust manifold

16. COMPONENTS OF FUEL SYSTEM
IN SI ENGINE
 The fuel supply system of SI Engine consists of;
1. Fuel tank
2. Fuel lift pump
3. Fuel pipes
4. Sediment bowl (as a fuel filter)
5. carburetor

17. CARBURETOR
 It is very important
component of SI Engine
fuel supply system.
 The process of preparing
air-fuel mixture away from
the cylinders of an engine
is called carburetion.
 The device in which this
process takes place is
known as carburettor.

19. METHODS TO SETUP CARBURETOR
 On the basis of ways of mounting the carburetor
on the engine body, it may divided into two
classes;
1. Downdraft carburetor
2. Updraft carburetor

20. DOWNDRAFT CARBURETOR
 Mounted above the intake manifold.
 Air enters the upper part of carburetor.
 After the creation of air-fuel mixture, it flows downward
into manifold.
 Commonly used in automobile, trucks and stationery
engines

21. UPDRAFT CARBURETOR
 It mounted below the engine block.
 The mixture flows upward into the engine.

22. FUNCTION OF CARBURETOR
 To mix air and fuel thoroughly
 To atomise the fuel
 To regulate air-fuel ratio at different speeds and
loads
 To supply the correct amount of mixture at different
speeds and loads

23. COMPONENTS OF CARBURETOR
• It produce pressure difference in
tube
• Due to low pressure, fuel sucked
into tube
Venturi
tube
• It maintain the constant level of
fuel in carburetor
Float
chamber
• To regulate the quantity of charge
Throttle
valve

24. • It regulate the air supply in
carburetorChoke valve
• It regulate the fuel supply in the
main jetEconomiser
• It is a small opening through
which fuel passes from float
chamber to throttle
Jet

25. FUEL SUPPLY SYSTEM IN
DIESEL ENGINE

26. FUEL SUPPLY SYSTEM OF
DIESEL ENGINE
 Fuel is drawn from the fuel tank by feed pump and forced
to the injection pump through fuel filter.
 The injection pump supplies high pressure fuel to
injection nozzles through delivery valve and high pressure
pipes.
 Fuel injected into the combustion chamber through
injection nozzles.
contd…

27.  The fuel that leaks out from the injection nozzles passes
out through leakage pipe and returns to the fuel tank
through overflow pipe.
 The fuel pressure at the feed pump must be in the range
of 1.5 to 2.5 kg/cm2

28. FLOW DIAGRAM OF FUEL IN
DIESEL ENGINE
FUEL TANK
OVER FLOW PIPE
SEDIMENTAL
BOWL
LIFT
PIMP
FILTER
INJECTION
PUMP
INJECTOR
COMBUSTION
CHAMBER

30. • To store the fuelFuel tank
• Used as a secondary storageSediment bowl
• To force the fuel into filterLift pump
• To remove the dirt materials (both P
& S filter)Fuel filter
COMPONENTS OF FUEL SUPPLY
SYSTEM OF DIESEL ENGINE

31. • Supply high pressurized fuel according
to firing order of cylindersInjection pump
• To deliver the fuel into injectorsPressure pipe
• To inject the fuel into combustion
chamberInjectors
• Chamber in which combustion takes
place
Combustion
chamber
• To flow out the exhaust gases from
engine
Exhaust
manifold

32.  There are some important components of
fuel supply system;
1.Fuel filter
2.Fuel injection pump
3.Fuel injector

33. FUEL FILTER
There are two types of filters:
1. Primary filter :- It
removes coarse material,
water and dust
2. Secondary filter :- It
removes fine dust
particles
The filters are made of different
materials like:-
1. Metal elements
2. Felt & cloth
3. Paper disc
4. Porous metal filter

35. FUEL INJECTION PUMP
 It is a high pressure pump, which supplies fuel to the
injectors according to the firing order of the engine.
 It is used to create pressure varying pressure from 120
kg/cm² to 300 kg/cm².
 It supply metered quantity of fuel each cylinder at proper
time.
 Types of fuel injection pump:
1. Multi element pump.
2. Distributer (Rotary) pump.

37. FUEL INJECTOR
 It is the component which delivers finely
atomised fuel under high pressure to the
combustion chamber.
 There are three types of injectors:
1. Pintle type
2. Throttle type
3. Hole type

38.  The fuel injector
consists of the following
components:-
1. A needle valve
2. A compression spring
3. A nozzle
4. An injector body
COMPONENTS OF
FUEL INJETCTOR

40. PRECAUTION IN HANDLING
OF FUEL SYSTEM
 Fuel :
1. High quality fuel is necessary to the fuel injection
pump.
2. Only filtered fuel should be supply to the fuel tank.
 Fuel tank cleaning:
1. Water and deposits should be drained from the fuel
tank at least every six month.

41. Thanks!
Any questions?