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 The Electronic Injection System
The Injector Valve has the finest
tolerances of any mechanical component
on the engine.
How do we check these tolerances?
We are constantly checking Milliseconds,
Millivolts, Milliamps.
When do we check Millilitres of
fuel?
Un-burnt fuel is the biggest issue
on the petrol combustion engine
today.
How often do we check the Millilitres
of Fuel being delivered to the
engine?
How the
Electronic Injector works
The injector is located
in the inlet manifold of the engine
and sealed in between the manifold
and fuel supply rail by Viton
rubber seals. A fuel pump pressurises
the system to normally about 2.5
bar.
The Engine Control Unit (ECU)
gathers information from the various
sensors located around the engine
and using this information, the
ECU determines the opening duration
required for that combustion stroke.
To do this, the ECU generates
a current and transmits it to
the solenoid of the injector.
The solenoid will magnetically
lift the pintle valve needle from
the seat of the injector, varying
between 60 - 100mm. While the
valve is raised, the pressurised
fuel is forced through the orifice
gap in the bottom of the injector,
on to the pintle head or orifice
plate and form a spray pattern
shape as nominated by the head
or plate design.
The injector will remain open
for anywhere between 1 - 20 milliseconds,
at a frequency of 3 - 125 Hz,
depending on the engines requirements.
When the current is stops, a small
coil spring pushes the valve needle
to the pintle seat and stops any
further fuel from passing through.
This process is repeated many
time a second.
Due to demands for various fuel
quantity deliveries and spray
formations, Robert Bosch alone,
produce over 1100 different injector
part numbers.
The Electronic
Petrol Injector Valve - Serviceable
Parts
Unlike Diesel Injectors,
Gasoline Electronic Injector is
a sealed unit and cannot be dismantled
or have any of its internal Mechanical
or Electrical components replaced.
Only the external components and
the internal filter basket can
be replaced.
All rubber Fuel & Air seals
should be replaced if injector
are removed from engine.
Engine
Related Problems
Recognise the symptom,
what’s the cause?
•
Starting Problems...Difficult
to start, hot or cold or will
not start at all.
•
Poor Fuel Economy...Vehicle has
good performance, but excessive
fuel consumption.
•
Excessive Exhaust Emissions...Failure
on exhaust emissions, no adjustment
available. Lambda or Catalyst
exhaust failure.
•
Idling Problems...Un-even idling,
surging, misfiring, ‘pinking’
adjustment fails to resolve problem.
• Lacking Performance...Lack
of power, flat spots, poor throttle
response, car not performing like
it use to.
• Poor Driveability...The
car hesitates, ‘pinks’
under load, erratic performance
and throttle response.
•
ECU Error Warning Codes...Error
code shows fault with Lambda or
Air/Fuel mixture and checks show
no fault.
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Engine
Related Problems
Symptom, Cause, Consequence,
Results?
• Leaking
Injector Valves will cause: Wetting
of the manifold walls, that will
cause Starting problems, Inlet
Valve Gumming & Valve Sticking
, Bore Wash, causing Loss of Compression,
Lacquering of the Oxygen Sensor
, causing slow Lambda response
time & Clogging or Failure
of the Catalyst Exhaust , causing
serious loss of performance or
non starting.
•
Poor Fuel Distribution & Atomisation
will cause: All of the above,
plus Excessive Exhaust Emissions,
Poor Fuel Economy, Idling Problems,
Lack of Power, Poor Driveability.
• Un-even Fuel Delivery
Rates will result in: Incorrect
Exhaust Emissions, Lambda Sensor
& Catalyst Exhaust Problems,
Idling Problems, Lack of Power,
Poor Driveability.
Fuel
Spray Management
What is a good spray
pattern?
See the cause, understand the
problem.
FAIR but weak.
BAD Split spray pattern
BAD Split spray pattern
BAD Jetting on left side
GOOD.
BAD Feathering at top of spray
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Fuel
Delivery - Quantity & Distribution
The Fuel Delivery and
the Fuel Distribution can simultaneously
be measured and visually examined.
The Distribution is measured by
the length of penetration into
the delivery tube.
The ideal requirement would be
that all the penetrations reach
the same length.
An imbalance in the distribution
length would cause a change in
the Air/Fuel ratio and result
in any of the afore mentioned
symptoms.
Fuel
Spray Management
New Injectors may not
solve the problem
Correct spray patterns are critical
to good performance, fuel economy,
drivability and exhaust emissions.
New injectors do not guarantee
correct spray patterns, as this
picture shows.
Fuel
Droplet Formation - Correcting
the Problem
Seeing the problem
is easy, correcting it is not.
So what is the answer? Fitting
new injectors? Flushing some chemical
through the system? No!
THE ANSWER IS ASNU’S PATTENTED
ULTRASONIC CLEANING PROCESS.
The only way to get your injectors
back to AS NEW (ASNU) condition.
Ultrasonic
Cleaning
The shape and design
of a Pintle type injector is critical
to the fuel Distribution &
Atomisation
Cleaning ensures that the injector
can function as it was designed.
Chemical
Cleaning
Chemical cleaning only
clean the parts that they touch.
Areas where the chemical has failed
to clean will cause disruption
to the fuel Distribution and Atomisation.
Chemicals only go one way as quickly
OUTWARDS!
Problems?
Now you can find the
Cause of the Problem?
Now you recognise the need for
Injector Diagnostics
Welcome to the World of ASNU
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