[Diy_efi] Design of a simple LPG injection system

[Mike]

At 07:51 AM 30/1/2003 +1100, you wrote:
>My name is Peter Sterling and I am in Australia. I am working on a
>concept of using an interceptor to alter timing signals from the ECU and
>control a large single LPG injector. I propose to start on petrol and
>once warmed up  switch to LPG. The idea is to make a simple and
>inexpensive system to replace venturi type LPG systems.

Heard of one which put the LPG directly as liquid into intake ports
just next to existing petrol injectors...

>It seems that several types of modern vehicles have a lot of problem
>with backfiring on LPG and detroying both the airflow meter and the air
>filter box. This seems to be - on the surface - more common with wasted
>spark systems. Could it be a product of maintaining the standard petrol
>timing map without interception and remaping for LPG.

Several cars had this problem, especially the VL range by GMH, the
turbo models were the worst for backfire - no wasted spark on
either NA or turbo model.

>I am looking at positioning the injector just prior to the thottle body
>- mounted in a machined adaptor ring.

Why ? Safer would be after TB, you limit and reduce the volume of
a combustible mixture to the plenum and not the whole intake system,
might want to consider using a burst valve on the plenum though
and of course depends on what safety mechanisms you have as
backup so there is no chance of trickle depending on what type
of injector you use...

rgds

mike










 Tuning would be by using a wide
>band oxy sensor calibrated for LPG.

>I assume that various LPG discussions have taken place on the site over
>the years and I am currently searching the achives to look for info. If
>there is other important information I need specific to this project can
>anybody direct me there please.
>
>Is there anyone else on this site interested in discussing how one might
>get such a system up and running within 12 months.
>
>By the way I have a good friend who managers the quality assurance
>laboratoties for BOSCH Australia. If you are after info on Bosch ECU's I
>may be able to get some info from him.
>
>Regards
>Peter Sterling
>
>
>
>
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>
>

Kind Regards  ~`:o)

Mike Massen
Network Power Systems
Perth, Western Australia  Ph/Fx +61 (0)8 9444 8961, Mb +61 (0)438 048961

Power system in Jungle, Twin tyre car, Differential gauge experiment
http://members.iinet.net.au/~erazmus/index.html

Some say there is no magic but, all things begin with thought then it becomes
academic, then some poor slob works out a practical way to implement all that
theory, this is called Engineering - for most people another form of magic.

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