02-01-2013, 01:21 PM
MULTI POINT FUEL INJECTION SYSTEM
MULTI POINT.ppt (Size: 749 KB / Downloads: 107)
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
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
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