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The ASNU system is designed for safely comparing fuel injectors at lower operating pressures, making it suitable for mechanics of all skill levels. It allows for detailed examination of injector spray patterns and performance, which is crucial for maintaining fuel economy and emissions in GDI systems. Current engine management systems cannot adequately measure or compensate for discrepancies in injector fuel distribution and atomization, highlighting the importance of using the ASNU system for accurate assessments.

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47 views1 page

As3 3

The ASNU system is designed for safely comparing fuel injectors at lower operating pressures, making it suitable for mechanics of all skill levels. It allows for detailed examination of injector spray patterns and performance, which is crucial for maintaining fuel economy and emissions in GDI systems. Current engine management systems cannot adequately measure or compensate for discrepancies in injector fuel distribution and atomization, highlighting the importance of using the ASNU system for accurate assessments.

Uploaded by

vivum
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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Spray Pattern & Flow Rate Analysis

The ASNU system has been designed for comparing injector


against injector at a safe operating level and is suitable for use
by Apprentice Level Mechanics to Master Level Technicians.
To enable a safe and easy examination of the injector’s
performance, the ASNU system runs the injectors at a lower and
safer operating fuel pressure of up to a maximum of 10 bar. On
a vehicle fitted with a GDI system the fuel pressure will operate
at a potentially dangerously high level for the inexperienced,
reaching anywhere between 75 bar up to 200 bar on some
systems.
The Engine Management System of a GDI is designed to open the
injectors for short micro second durations, with a maximum
opening duration of only 5 milliseconds, any visual analysis of the
injectors spray pattern could be both difficult and dangerous.
When mounted on the ASNU Classic GDI, the injectors are being
supplied with the correct peak and hold currents and firing in
sequential mode simulating those of the vehicles ECU.
The ASNU allows the
user to safely examine the injectors spray pattern in greater
detail for any discrepancies in the fuel distribution and
atomisation.
In some operating modes, the ASNU system opens the injectors
for a much longer duration, thus exaggerating the spray pattern
and making it easier to examine the spray’s performance.

GDI Injectors & Fuel Trims


The Distribution and Atomisation on a GDI Injector are critical to maintaining the correct Performance,
Fuel Economy and Exhaust Emissions. They are now even more important than the quantity of fuel being
delivered by the injector. The latest Adaptive Engine Management Systems have a Short and Long Term
Fuel Trim Adjustment, adjusting the fuel delivery as compensation for any discrepancies in the C.O
emissions. An adjustment of up to 15% can be made to the fuel delivery of each injector on some systems,
but as there are a number of measurements that contribute to the Fuel Trim Adjustment, these
measurements cannot adjust or correctly compensate for poor Fuel Distribution and Atomisation.
FUEL TRIM ADJUSTMENTS ARE NOT CORRECTING THE PROBLEM,

NONE OF THE CURRENT ENGINE


MANAGEMENT SYSTEMS CAN
MEASURE OR COMPENSATE FOR
THE INJECTORS FUEL
DISTRIBUTION AND ATOMISATION

A selection of GDI Injectors with


discrepancies in the Distribution and
Atomisation of the spray patterns

The ASNU system allows the user to visually examine the injectors on an individual cycle or in sequential
mode, where they can compare the injectors performance under a range of simulated Millisecond & RPM
driving cycles already programmed in to the ASNU system. The injectors can be operated at various RPM
& Millisecond settings, restricted only by the number of injectors being tested in the sequential testing
operation.

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