The document discusses multi-point fuel injection (MPFI) systems. It begins by defining MPFI as a system that uses fuel injectors in each engine cylinder rather than a carburetor to mix fuel and air. It then explains the components of an MPFI system, including fuel injectors, fuel filters, pressure regulators, and sensors that provide input to the engine computer. The document outlines how the computer calculates the optimal fuel amount for each cylinder based on various inputs and controls the injectors accordingly. MPFI systems provide benefits like improved fuel efficiency, reduced emissions, and better engine performance compared to carbureted engines.

1. MULTI POINT FUEL INJECTION
SYSTEM
MPFI SYSTEM)

2. INTRODUCTION
 What is MPFI?
 We will be familiar with the word MPFI in the
advertisement of some vehicles.
 But how many of us know what MPFI exactly is?
 The term MPFI is generally used to specify an engine
variant used in the petrol vehicles.
 A small computerized system is used to control the
engine of the car. A petrol car will have more than three
fuel burning chambers or simply cylinders. The MPFI
engine is abbreviated as the Multi point fuel injection
engine. The MPFI engine got this name because of the
reason that each cylinder is having a fuel injector
installed near them. That is why they are called as the
Multi point fuel injection engine.

3. WHAT IS FUEL INJECTION?
 First of all we should know that
what is fuel injection is actually
mean.
• FUEL INJECTION IS A MEANS OF METERING FUEL INTO
AN INTERNAL COMBUSTION ENGINE. IN MODERN
AUTOMOTIVE APPLICATIONS, FUEL METERING IS ONE OF
SEVERAL FUNCTIONS PERFORMED BY AN "ENGINE
MANAGEMENT SYSTEM".
• FOR GASOLINE ENGINES, CARBURETORS WERE THE
PREDOMINANT METHOD TO METER FUEL BEFORE THE
WIDESPREAD USE OF FUEL INJECTION. HOWEVER, A WIDE
VARIETY OF INJECTION SYSTEMS HAVE EXISTED SINCE THE
EARLIEST USAGE OF THE INTERNAL COMBUSTION ENGINE.

4. • THE PRIMARY FUNCTIONAL DIFFERENCE
BETWEEN CARBURETORS AND FUEL INJECTION IS
THAT FUEL INJECTION ATOMIZES THE FUEL BY
FORCIBLY PUMPING IT THROUGH A SMALL
NOZZLE UNDER HIGH PRESSURE, WHILE A
CARBURETOR RELIES ON THE VACUUM CREATED
BY INTAKE AIR RUSHING THROUGH IT TO ADD
THE FUEL TO THE AIRSTREAM.
• THE FUEL INJECTOR IS ONLY A NOZZLE AND A
VALVE: THE POWER TO INJECT THE FUEL COMES
FROM FURTHER BACK IN THE FUEL SUPPLY, FROM
A PUMP OR A PRESSURE CONTAINER.

5. PRINCIPLE OF MPFI SYSTEM
 The power is produced in a petrol engine is by burning
the fuel. In petrol engine, the petrol is ignited. At first,
the petrol is allowed to mix with air. It is then ignited in
a cylinder called as the combustion chamber. This
combustion of the petrol produces a sufficient energy
to run the engine. The Carburetor is being used in the
earlier days before the invention of MPFI engine. It is
the duty of the carburetor to mix the fuel and air in a
fixed air-fuel ratio. The fuel thus mixed in the
carburetor is then given to the combustion chamber
where this mixture gets ignited.

6. COMPONENTS OF MPFI SYSTEM
 THE FUEL INJECTOR
• Here the figure shows the simple
construction of a fuel injector.
• It consists of :
 1.Electric connector
 2.Spring
 3.Electric coil
 4.Piston
 5.Plunger
 6.Injector orifice


7.  As shown in figure the pressurized fuel first enters
at the back side of the injector. Now the electrical
attachments operates the solenoid with reference of the
sensor’s input to it. It turns the solenoid on and off
when the fuel supply is needed or not respectively.
 The solenoid is directly connected to the piston and
plunger. The plunger is operated with the help of valve
spring and when the solenoid if turned on it allows the
flow of fuel through the orifice at the end. Thus the fine
spray of fuel is obtained.

8.  HIGH PRESSURE FUEL FILTTERS
Applications
Gasoline Passenger Cars & Vans
 Function
To reduce the particulate impurities
 Range
Capable of withstanding pressure
from 3.5 to 5 Bar
Provision for accommodating
bracket for mounting on to vehicle
 Technology & Special Features
Double folded paper element
 Customers
Maruti Suzuki and other
applications

9.  PRESSURE REGULATORS
 Applications
Gasoline Passenger Cars & Vans
 Function
To regulate fuel pressure in
delivery pipe of MPFI engine
 Range
2.8 to 3.8 bars
 Customers
Maruti Suzuki, Hyundai

10. WORKING OF MPFI SYSTEM
 The MPFI is an advanced version of carburetor
engine. As we said earlier that the MPFI engine
is having a fuel injector for each cylinder. A
computer is used to control each and every fuel
injector individually. The computerized system
of the car consists of a microcontroller. This
microcontroller monitors each fuel injectors
and keeps on telling each injector about the
amount of fuel to be injected to the cylinder so
that the fuel wastage can be reduced. Since
there is a controlled fuel usage, the engine is
known for its fuel efficiency.

11.  Even though the working of MPFI engine is
somewhat similar to the carburetor engine,
each cylinder is treated individually. An input is
fed to the computerized system in order to
calculate the amount of air and fuel is to be
mixed and send to the combustion chamber. A
several stages of calculations are to be made in
order to judge the right amount of fuel to be
mixed. After this calculation, the proper fuel is
delivered at the proper instance.

12.  There are a number of sensors used in the MPFI engine. At the
time when the inputs are given to the car's computer, it begins to
read the given sensors. The things which can be known from the
sensors are listed below:
 The engine temperature of the vehicle.
 The speed at which the engine is running.
 The engine load.
 The position of the accelerator.
 The cylinder's air-fuel pressure.
 The rate of exhaust.

13.  The figure shows stages 1 & 2.
 In the 1st stage due the signals
given by the computer system
of the car to the 1st injector a
specific amount of fuel is
supplied to it.
 Now when the sensors senses
the condition of engine the
solenoid is turned on and the
plunger is lifted up to allow the
flow of fuel to the orifice which
forms a fine spray of fuel
supplied.

14.  The figure shows the stages 3
&4.
 The 3rd stage shows the same
operation for 2nd injector or 2nd
cylinder. The working of
injection is same as explained
earlier.
 The 4th stage shows the
working of injection system for
3rd cylinder.

15.  The amount of fuel to be injected into the combustion
chamber is decided by analyzing the inputs given to the
computerized system of the MPFI engine. In modern
MPFI engines, a memory unit is additionally installed.
This will make the MPFI engine capable of storing the
user settings so that it can operate easily. The driving
habits of a driver can also be detected by this system so
that the MPFI system itself can change the predefined
settings which suit the user. There are namely two types
of MPFI engines namely:
 Sequential
 Simultaneous
 Thus it can be noted that the cars of today are truly
intelligent.

16. OBJECTIVES OF MPFI SYSTEM
 The functional objectives for fuel injection systems can vary. All
share the central task of supplying fuel to the combustion
process, but it is a design decision how a particular system is
optimized. There are several competing objectives such as:
 1.Power output
 2.Fuel efficiency
 3.Emissions performance
 4.Ability to accommodate alternative fuels
 5.Reliability
 6.Driveability and smooth operation
 7.Initial cost
 8.Maintenance cost

17. ADVANTEGES OF MPFI SYSTEM
 1.IMPROVED FUEL CONSUPTION
 Vehicles with dual point fuel injection or carburetors do
not get nearly the fuel economy of those with multi-
point fuel injection.
 A multi-point fuel injection system, which uses one fuel
injector for each cylinder of the engine, delivers just the
right amount of
 gas to each cylinder. Thus, gas is not wasted in the
process.
 Over time, the gas saved with a multi-point fuel
injection system saves the vehicle owner loads of
money.

18.  2.EMISSION
 A car from this century emits a small fraction of what a
vehicle emitted even a few decades ago.
 Multi-point injection systems are better for the
environment because the emissions of hazardous
 chemicals being released when fossil fuels are burned
are minimized.
 As mentioned above, the more precise delivery of fuel
to the engine means that fewer noxious byproducts
 are released when the fuel combusts within the engine.
The implements within the engine meant to clean the
 exhaust have been fine-tuned in a multi-point system to
work more efficiently.
 Therefore, the engine--and the air--is cleaner as a result
of multi-point systems.

19.  3.BETTER PERFORMANCE
 The performance of an engine suffers with the use of a
carburetor, but multi-point fuel injection allows for far
better engine performance.
 Instead of allowing for additional air intake, multi-
point injection atomizes the air that is taken through a
small tube.
 Because multi-point injectors are usually controlled by
computers, each function of a carburetor is performed
by a different system component.
 These systems also improve the cylinder-to-cylinder
distribution of an engine, which allows it to conserve
energy.

20. PREPERED BY:
Dodiya Aalap A.(120400119105)
Das Jigar D.(120400119099)
THANK YOU