The document discusses various fuel feed systems for petrol engines. It describes gravity, air pressurized, vacuum, pump, and fuel injection systems. It explains that modern vehicles primarily use fuel injection systems with separate injectors for each cylinder. The fuel injection system provides more accurate control of the air-fuel mixture than earlier carburetor systems. Key components of fuel systems are also outlined, including the fuel tank, filters, fuel lines, carburetor or injectors, and engine management systems.

1. Fuel feed system in
petrol enigine
Presentation
by
G. JAGADEESKUMAR
JTO/MMV GOVT ITI
DHARMAPURI

2.  The main purpose of the fuel feed system is
to control the fuel supply to the engine.
 To supply the fuel from the fuel tank to the
engine cylinders.

3.  Gravity fuel Feed system
 AIR Pressurized fuel Feed system
 Vacuum fuel Feed system
 Pump fuel Feed system
 Fuel injection fuel Feed system

4.  The ‘gravity system’ is confined to smaller
vehicles such as entry-level two-wheelers,
bikes, and quads only. In this design, the
engineers mount the fuel tank at the highest
position.
 It feeds the fuel into the carburetor float
chamber by gravity. This system has a very
simple design and hence, cheaper to produce
and maintain. However, the disadvantage is
that you need to place the fuel tank over the
carburetor for this system to work correctly.

6.  In this system, an airtight fuel tank is used
and is placed under the seat or near the
engine.
 the hand operated a pump or mechanically
operated pump supplies the high-pressure
air to the fuel tank for supply the fuel to the
carburetor.

8.  This system uses engine suction pressure to
suck the fuel from the main tank to an
auxiliary tank
 The fuel flows to the carburetor float
chamber by gravity.
 This system is now obsolete.

9.  Most present-day cars use this system. This
system uses a steel pipe to supply the petrol to
the fuel pump which then pumps it into
the carburetor float chamber thru’ flexible pipe.
 If it is a mechanical fuel pump, then it gets the
drive from the engine camshaft. Hence, it is
attached to the engine. On the other hand,
electrically operated fuel pumps can be placed
anywhere. So, manufacturers place it inside the
fuel tank to reduce the chance of vapor-lock.

11.  Modern/present-day vehicles use petrol
injection system which replaced the
carburetor. The injector nozzle atomizes the
fuel and forces it into the air stream. Newer
generation engines use separate injector for
each cylinder. The air-fuel mixture for
different load and speed conditions is
controlled either mechanically or
electronically. Hence, this makes the fuel
system more accurate. For more information,
read about the EFI, MPFI & GDi.
 Modern/present-day vehicles use petrol
injection system which replaced the
carburetor. The injector nozzle atomizes the
fuel and forces it into the air stream. Newer
generation engines use separate injector for
each cylinder. The air-fuel mixture for
different load and speed conditions is
controlled either mechanically or
electronically. Hence, this makes the fuel
system more accurate. For more information,
read about the EFI, MPFI & GDi.

12.  Fuel tank
 Filters
 Fuel pump
 Fuel lines
 Carburetor or injectors
 Engine-management system
 Fuel gauge

13.  The fuel tank holds the fuel for the engine its imade up of stee or
aluminium or synthetic rubber components and fibre reinforced
plastics which are flame resistant
 The tank are coated with lead-tin alloy to protect the tank from the
corrosion effect

14. Filter made up of paper
or ceramic element
 Fuel filter is placed
between petrol feed
pump and carburettor
 A fuel filter is a filter
in the fuel line that
screens out dirt and
rust particles from the
fuel, normally made
into cartridges
containing a filter
paper

18.  A fuel line is a hose used to bring fuel from
one point in a vehicle to another or from a
storage tank to a vehicle. It is
commonly made of reinforced rubber to
prevent splitting and kinking.

19.  The main function of carburetors to mix air
and gasoline and provides a high combustion
mixture.
 It controls the engine speed. It also regulates
the air-fuel ratio.
 Increase or decrease the amount of mixture
according to the engine speed and load
changing

22.  The function of a carburetor is to vaporize the
petrol (gasoline) by means of engine suction and
to supply the required air and fuel (petrol)
mixture to the engine cylinder.
 During the suction stroke, air flows from
atmosphere into the cylinder. As the air passes
through the venturi, velocity of air increases and
its pressure falls below the atmosphere.
 The pressure at the nozzle tip is also below the
atmospheric pressure. The pressure on the fuel
surface of the fuel tank is atmospheric. .

23.  Due to which a pressure difference is created,
which causes the flow of fuel through the fuel
jet into the air stream.
 As the fuel and air pass ahead of the venturi,
the fuel gets vaporized and required uniform
mixture is supplied to the engine
 Note
◦ Automization
◦ Evaporation
◦ Carburation (homogeneous mixture)
◦ Carburettor popping due to back fire of lean mixing

25.  Float circuit
 Starting circuit
 Idling circuit and slow speed
circuit
 Main/high speed circuit
 Acceleration pump circuit
 Econostat circuit

27.  Separate circuit for different, scanario like
starting circuit, idling,acceleration..
 Esee of starting the Bi starer helps to cold
starting of the vehicle
 Throttle responds increase
 Solex carburettor has an additional pump
circuit for suddern acceleration requirement
 Easily change flow rate of air fuel ratio.