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Gary,
It is interesting that the Bendix system was/is a
reasonably high pressure system.
I have been reading about the progressive
development of injection system and find it very interesting.
Quite obviously you have the knowledge and now that
I have your ear, I am eager to learn more about your low pressure
systems.
Personally I would like to have a low pressure
mechanical system. I was reading about one such system that had a 'spoon
like' fuel actuation injection device . I may be reading more into it than
there is, however it sounds, to me, like a small airfoil within the inlet
manifold, whereby the air speed and density had a direct effect upon the
actuation of the metered fuel - purely mechanical. To me that sounds ideal for
light aircraft application. My preference in no way 'poo-poos' computerized
fuel management systems or direct injection, rather I see it as the poor mans
simplified system. I still see the need for an O2 sensor for monitoring a
manual leaning facility.
George (down under)
George,
Well, there are "low pressure systems" and "low pressure systems".
Depends on the point of view, I guess. We're not talking about high
pressure direct injection (GDI) systems that are now all the rage.
The original Bendix system ran at 39 psi - a little higher than the Bosch
systems at the time,which were, I think 29 psi (exactly 2 bar - a
coincidence?) systems. The reason was that one of our applications was
the Cadillac V8 and the injectors were in a hotter location. The higher
pressure was to keep vapor formation at bay during a hot soak. Then some
turbo Chrysler applications used 60 psi for the same reason. The
injector design was the same and most injectors will still open at pressures
up to about 100 psi. There were some lower pressure systems (about 20
psi, I think) that used clever injector designs to reduce sensitivity to vapor
formation. Well, I thought they were clever because some were
mine. Higher pressure operation can improve atomization, but that isn't
a big consideration. Lower pressure systems once allowed a lower cost
fuel pump to be used, but that isn't true any more. No, I don't think
lower pressure systems are coming back.
None of this discussion pertains to the "Bendix" aircraft injection
system, which is a totally different concept.
Gary
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Cary,
Very interesting, thank you for that
info.
Bendix is a low pressure injector system is it
not?
I have been reading about the benefits of low
pressure systems - are they coming back in vogue?
George ( down under)
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