Fuel injection in si engine by shubham sanjay sorate ph.no.8421592224
Transition of Fuel Supply System
Carburetor Port Injection
ADVANTAGES OF FUEL INJECTION OVER CARBURETOR
☼ Fuel injection has no choke, but sprays atomized fuel directly into the
☼ Electronic fuel injection also integrates more easily with computerized
engine control systems.
☼ Multi port fuel injection delivers a more evenly distributed mixture of
air and fuel to each of the engine's cylinders.
☼ Sequential fuel injection improves power and reduces emissions.
Petrol injection system
Gasoline direct injection
( manifold injection)
Single point injection Multi point fuel injection
Throttle injection Port injection
Throttle injection Port injection
TYPES OF PETROL INJECTION
In indirect fuel is injected into the air stream before
entering the combustion chamber.
And in direct injection system fuel is injected directly
inside the combustion chamber.
Indirect injection Direct injection
Single Point Injection system
The earliest & simplest type of fuel injection, single
point simply replaces the carburetor with one or two
fuel injector nozzles in the throttle body, which is the
throat of the engine’s air intake manifold.
Single point injection system meters fuel better than a
carburetor and is less expensive and easier to service.
The indirect injection can be classified as single point
injection and multi point fuel injection.
The single point injection also called Throttle
injection in which fuel is injected at one place in
throttle body, and the mixture supply to different
cylinders as shown in fig…
In case of Port injection also called multi point
fuel injection, air sucks through throttle body, and
fuel is injected near inlet valve of every cylinder as
shown in fig….
Multi Point Fuel Injection System
MPFI system is widely used in petrol engine in place of
Purpose of MPFI is supply proper A/F ratio to each
cylinder of engine.
Fuel tank > Pump > High pressure petrol > Distributor
> Fuel injector > Cylinder
Now a days MPFI system control by Electric Control
Ecm receives signal from different sensors.
ECM receives signal and send to the solanoid operated
fuel injector to meter and inject right amount of fuel at
There are different type of sensors in MPFI system.
1. Inlet manifold pressure sensor
2. Air flow sensor
3. Engine speed sensor
4. Throttle position sensor
5. Coolant temperature sensor
6. Inlet air temperature sensor
7. Knock sensor
8. Exhaust gas sensor
Direct injection (GDI)
These systems inject the fuel directly into the combustion
chamber, either during the intake stroke or during the
There are two basic type of GDI, either injection of gasoline
alone, or a duel injection of gasoline and air together.
Injection of fuel alone is usually done during the
compression stroke and is somewhat similar to fuel
injection in CI engine. Because of the very short time
available for vaporization and mixing with air, very fine
droplets of fuel are required, as are high turbulence and
bulk mass motion within the combustion chamber
Injector pressure must be higher than that require for
This is because of the higher pressure into which the
fuel is being injected, and because of the requirement
for finer droplets of fuel.
Pressure required for fuel injection is above 40 to 65
Modern gasoline engine may utilized Direct injection
using electric control.
3.350Fuel Pressure (MPa)
Port InjectionIn-Cylinder Direct InjectionFuel System
StandardUpright StraightIntake Port
Flat top PistonCurved Top PistonCombustion Chamber
Intake: 2, Exhaust: 2Number of Valves
IL-4Number of Cylinders
81.0 x 89.0Bore x Stroke (mm)
Fuel injection in two wheelers
1.It uses advanced sensors and actuators
to calculate and deliver the optimum
amount of fuel to the engine –
enhancing both performance and
2. more responsive leading to quick
initial pickup and delivering smooth
3. It achieves a 14% improvement* in
4. its intake/exhaust valve layout is
designed to best match the
hemispherical combustion chamber. In
combination with the optimized intake
and exhaust port shapes, this design
increases combustion speed and helps
achieve excellent combustion
efficiency. The new engine further
improves fuel efficiency and the feeling
of acceleration while retaining the
excellent performance qualities of the
current FZ engine.
Advantages of Direct Injection
Higher volumetric efficiency
Easy cold starting
Lower exhaust emission
Higher efficiency and better mileage
From this conclude that the fuel injection system is
more efficient than the conventional mpfi and diesel
It improves the engine efficiency
More convenient to use than the diesel engine
It gives better performance than the diesel engine.
Lower exhaust emission
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