singla ppt on mpfi

7/29/2019 Singla Ppt on Mpfi

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MPFI(Multi Point Fuel Injection)

Done By

Er.Rohit Singla

R0ll no: 2306643


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Introduction

In petrol vehicles carburetor is used for supplying airfuel mixture to the cylinder

In response to the recent demand for cleanerexhaust emission improved drivability and mileagecarburetor is not sufficient

In place of the carburetor MPFI system is used invehicles

MPFI system is injects fuel into individual cylinders

based on commands from engine control module The MPFI gives higher output, faster throttle

response under varying driving conditions


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Components ofMPFI

The system has four major components they are

1. Air intake system

2. Fuel delivery system

3. Electronic control system

4. Emission control system

Air intake system

It includes air filter, throttle body, intake

manifold, and finally drawn into the combustionchamber


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Air intake system

Throttle body

It consist of throttle valve, T P sensor, which detectthe throttle valve opening

Idle air control valve which supplies bypass airdepending on the engine condition

Fuel delivery system It includes fuel pump, fuel filter and injector

Fuel pump

ECM controls its operation and centrifugal pump isused to pump the fuel

The fuel pump also has a check valve to keep somepressure in fuel feed line even when fuel pump is

stopped


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Pressure regulator system

It keep the fuel pressure applied to the

injector 2.9kg/cm^2 Injector

Each cylinder have one injector

It inject the fuel into the inlet manifold according tothe signal from ECM

Electronic control system

The electronic control system consist of varioussensors which detect the state of engine and driving

conditions


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Control systems are,

Fuel injection control system

In which ECM controls the timing of fuel

injection according to the signals from

various sensors

Injection time is calculated on the basisof engine speed

Idle speed control system

It keep the engine idle speed as specified

at all times


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Fuel pump control system

ECM controls the ON\OFF operation of

the fuel pump Ignition control system

This system controls ignition timing

The ECM judges the engine conditionsby using signals from various sensors

selects suitable ignition timing

Controls of this system includes Ignition timing at the engine start

Ignition timing after engine start


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Radiator fan control system

Radiator fan motor is turned ON and OFF by using

relays Radiator fan motor turned ON at below 98degree

Celsius and OFF at below93degree Celsius

Engine Control Module It consist of micro computer, analogue\digital

converter

It controls fuel injector, IAC valve, fuel pump relay

.etc


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Working


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Functional division of MPFI


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On-board diagnostic system

ECM diagnosis troubles which may occur in the engine

when ignition switch is ON and the engine is running, itindicates trouble to the driver by flashing malfunction

indication lamp

And it stores the data about the trouble in ECM back up

memory

Emission control system It includes evaporative canister

Evaporative emission control system This is used to prevent emission of fuel vapour


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Sensors used in MPFI

Manifold absolute pressure sensor

This sensor senses pressure change in the intakemanifold

The signals from the MAP is used by the ECM to controlfuel injection pressure

Throttle position sensor This is connected to throttle valve shaft on the throttle

body and detects throttle valve opening

Intake air temperature sensor

It located on the air cleaner outlet hoseand constantlymeasures the temperature of air entering to the intakemanifold

By sensing the temp. the ECM adjusts fuel injection

quantity


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Engine coolant temperature sensor It is incorporated with coolant and measures the

coolant temperatureOxygen sensor Oxygen sensor is installed on the exhaust manifold

to detect the concentration of oxygen in the exhaust

gases

It is necessary to keep the air fuel ratio within a

narrow range, and keep it in a stochiometric air fuel

ratio

Vehicle speed speed sensor The vehicle speed sensor is located on the

transmission gear box or speedometer


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Cam shaft position sensor

Using this signal ECM identifies cylinder whose

piston is in the compression stroke

Crank shaft position sensor

ECM uses this signal for knowing the enginespeed and cylinder identification


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Advantages of MPFI

1) More uniform A/F mixture will be supplied to eachcylinder; hence the difference in power developed ineach cylinder is minimum. Vibration from the engineequipped with this system is less, due to this the lifeof engine components is improved.

(2) No need to crank the engine twice or thrice incase of cold starting as happens in the carburetorsystem.

(3) Immediate response, in case of suddenacceleration / deceleration.


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Advantages of MPFI

Since the engine is controlled by ECM*(Engine Control Module), more accurateamount of A/F mixture will be supplied andas a result complete combustion will take

place. This leads to effective utilization offuel supplied and hence low emission level.

(5) The mileage of the vehicle will be

improved.


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Conclusion Almost all vehicles in India are changing to

the MPFI because of law emissions,improved mileage and drivability

Since the engine is controlled by microcomputer more accurate amount of A/F

mixture will be supplied and as a resultcomplete combustion will take place. Thisleads to effective utilization of fuel suppliedand hence low emission level.

It reduces wastage of fuel by the use ofsensors and other control systems


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singla ppt on mpfi

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