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MULTI POINT FUEL INJECTION SYSTEM
INTRODUCTION
MPFI- a technology used in petrol engines
Uses a small computer to control the car’s engine
In MPFI engine one fuel –injector is installed near each cylinder ,that is why it is called multi point fuel injection.
Before MPFI system, there was a technology called “Carburetor”
The computer in the MPFI system decides what amount of fuel to inject
System also learns from the drivers driving habits
MPFI system makes engine fuel efficient
OBJECTIVES
power output
fuel efficiency
emissions performance
ability to accommodate alternative fuels
reliability
drivability and smooth operation
initial cost
maintenance cost
diagnostic capability
range of environmental operation
Engine tuning
HISTORY AND DEVELOPMENT
Herbert Akroyd Stuart developed the first system
The first use of direct gasoline injection was on the Hesselman engine invented by Swedish engineer Jonas Hesselman in 1925
One of the first commercial gasoline injection systems -a mechanical system developed by Bosch and introduced in 1952 on the Goliath GP700 and Gutbrod Superior 600
Mechanical fuel injection systems
Chevrolet introduced a mechanical fuel injection option, made by General Motors' Rochester Products division, for its 283 V8 engine in 1956
Electronic fuel injection systems
First commercial EFI system was Electrojector- developed by the Bendix Corporation
EFI system in the Rambler was a far more-advanced setup
than the mechanical
types.
1958 Chrysler 300D, Dodge D500, Plymouth Fury, and DeSoto Adventurer-the first series-production cars equipped with an EFI system.
D-Jetronic was first used on the VW 1600TL/E in 1967
SUPERSESSION OF CARBURETORS
Extensive carburetor modifications and complexities were needed to approach stoichiometric engine operation
3 primary types of toxic emissions from an IC engine: CO, unburnt HC, and NOx
Fuel injection systems have significantly evolved since mid 1980s.
Current systems provide an accurate, reliable and cost-effective method of metering fuel and with clean exhaust emissions-replaced carburetors in the marketplace
The carburetor remains in use in developing countries
BASIC FUNCTIONS
Exhaust air or oxygen sensor
Engine temperature sensor
Air flow sensor
Throttle position sensor
Manifold pressure sensor
Camshaft position sensor
Knock sensor
FUNDAMENTALS OF FUEL INJECTION
MPFI Systems can either be:
Sequential
Simultaneous
Group
These techniques result in better ‘power balance’ amongst the cylinders, higher output from each one of them, along with faster throttle response
'Sequential' is the best from the above considerations of power balance/output
“Sefi’’-Sequential Electronic Fuel Injection - technically is the best of the above variants of MPFI
The ‘on-board’ ECU primarily controls the Ignition Timing and quantity of fuel to be injected
VARIOUS INJECTION SCHEMES
Port Injection
The injector is placed on the side of the intake manifold near the intake port
Every cylinder is provided with an injector in its intake manifold
Throttle Body Injection System
D-MPFI System
L-MPFI System
CONCLUSION
Improved fuel consumption
Better for the environment
Better performance