AG AUTOGAS SYSTEMS
developments are advancing with increasing speed in the
field of static ignition and multipoint-fuel systems for
The LPG in the current DGC autogas systems,
is fed into the engine’s intake system centrally (singlepoint).
In the future the singlepoint system will be increasingly
difficult to apply within the concept of an engine developed
for multipoint injection. In spite of the very good results
being achieved with current DGC systems.
AG Autogas Systems has the solution:
DGI - Digital
AG Autogas Systems has developed the DGI high-tech MULTIPOINT
GASEOUS LPG injection system over a period of 6 years.
The LPG injection which injects the LPG in pulses independently
timed for each cylinder, is a new feature of this innovative
as with a petrol injector, the quantity of LPG injected
is regulated by varying the duration of opening. In the
heart of the injector, a large plunger is drawn up electronically,
after which an LPG pulse is injected.
The DGI computer receives information from an orifice
meter which measures the volume of the LPG injected. Situated
behind the orifice meter, a splitter divides the main pulse
exactly into three or four equal parts.
The Closed-loop-flow feedback system compensates automatically
and immediately for variations in LPG pre-pressure or injector
behaviour so that this has no repercussions for the injection
The advanced DGI management computer uses engine-speed and
load sensor signals to calculate the basic quantity of LPG
injected for each engine revolution. This quantity is corrected
by lambda regulation, using the lambda signal in the exhaust
pipe, and any variations are stored in a memory index field.
During acceleration, extra fuel is injected for a short
time at high frequency while during deceleration the LPG
fuel supply is shut off. A unique feature is the electric
drive for the LPG injectors which is completely flow-regulated
and is thus independent of battery voltage and/or temperature
variations. The closed-loop flow regulation for the injector
uses the feedback flow-signal to control the duration of
opening so that the correct amount of LPG is injected.
For system control and diagnosis, the dealer can use the
Organizer from the AG test kit to establish direct contact
with the DGI computer.
All signals, self-learning data or error code data can thus
be checked and read out.
After installation, the DGI system must be briefly programmed
via this Organizer. In all cases, the R&D department
can be requested to perform a remote diagnosis via a modem
link and offer help where possible.
- DGI Multipoint LPG Injection greatly reduces the risk
- The difference in engine power-output between LPG and
the petrol original is almost zero, thanks to the absence
of a venturi choke.
- Better fuel-economy through shutting off of LPG injection
- Exhaust emissions satisfy the stringent European demands
and the Dutch G3 test.
- Because of the injector's high speed and wide opening,
the DGI system is not prone to fouling. This guarantees
optimum performance in summer and winter.
View pictures of a Range Rover 4.6
converted to LPG with a DGI system
SGI - Sequential
- The new LPG system for today and the future
Now from AG Autogas Systems,
SGI Sequential Gas Injection.
AG Autogas Systems has developed a new LPG system that
has almost identical characteristics to original petrol-injection
systems. This new system, Sequential Gas Injection (SGI),
has been developed at the request off, and in close collaboration
with various automobile manufacturers. AG has based the
development of SGI on their wishes with regard to the performance
and quality of LPG systems.
For the first time, attempts to design a LPG system while
retaining the original characteristics of the car have been
successful. This means that after the SGI system has been
installed, reliability and quality remain pretty well unchanged.
Comparisons of the car’s driving characteristics before
and after installation have shown very positive results.
- Performance equal to petrol injector
- Injection per cylinder with Sequential strategy
- Compact components
Liquid gas flows form the LPG tank to the regulator in
the engine compartment. The liquid gas is then vaporised
in this regulator and the LPG pressure adjusted to a stable
value. The LPG then flows through the common rail to the
SGI Injectors, which are attached to every inlet manifold.
The SGI computer calculates the desired injection moment
and the duration of injection for each cylinder required
Advantages of the SGI System
- Performance and driving characteristics almost identical
- Quality and reliability conform to automobile industry
- Suitable for worldwide retrofit market
- SGI meets new emission requirements and complies with
- Significantly lower fuel consumption
SGI meets EURO 4 emissions
Emissions result in EURO 4 test tested at TNO:
||0,97 gr/ km
||0,05 gr/ km
||0,04 gr/ km
||EURO 4 limit
DEVELOPMENT OF THE LPG MARKET
In Europe, the requirements regarding exhaust
emissions are being continuously tightened and this attention
to the environment is leading governments to encourage driving
on LPG. LPG is also receiving greater attention worldwide.
A great many large cities are increasingly permitting access
to LPG cars only in order to prevent smog.
The LPG market is clearly going to see further positive
development in the coming years. The demand for LPG systems
that satisfy the most stringent demands is keeping pace
with this. In the Netherlands, considerable reduction in
road-tax for cars equipped with the so-called ‘G3’
autogas system will increase drastically the demand for
THE NEW G3 REQUIREMENTS
For AG Autogas Systems, investment in developing
systems which satisfy the latest requirements was obvious
from the very beginning. Having anticipated changing requirements,
AG is now in a position to offer a fully operational DGI
system which not only achieves emissions of at least
30% below the standard for petrol (in accordance
with the new G3 requirements), but which also eliminates
the difference in performance between petrol and LPG
for the driver.
Digital Gas Injection is a self-learning, non-adjustable
system providing optimum engine performance and low exhaust
emissions and is developed by a company that satisfies the
stringent ISO 9001 standards.
DGI satisfies all the G3 requirements which
enable, in the Netherlands for instance, an immediate and
considerable reduction in road-tax for driving on LPG after
installation of the system.
The new Sequential Gas Injection system
is an excellent performing LPG/CNG system that is able
to meet EURO4 emissions limits and complies
with EOBD (European On Board Diagnostics) regulation.
Another advantage of using a DGI or SGI system is that
there is no risk of backfiring in the intake manifold.
ON A WORLDWIDE SCALE
AG Autogas Systems is one of the top autogas systems suppliers
and has been active worldwide in the market for more than
25 years. This market has developed to a high level in the
Netherlands and Italy in particular, and is why AG is chiefly
based in these countries. Close cooperation with a large
number of car manufacturers and importers means that the
AG systems can be offered on a worldwide scale.
AG has worked to a clear philosophy regarding quality.
The ISO 9001 certification.
Visit the AG
RANGE ROVER 4.6 CONVERTED TO LPG
WITH A DGI SYSTEM