[Diy_efi] Propane injection (KISS)

[Ray Drouillard]

The temperature at the injector should be about equal to the ambient
temperature.  The phase change will lower the temperature considerably after
it has been injected.


Ray Drouillard


----- Original Message -----
From: "Eck, Joel (Houston)" <Joel.Eck at hp.com>
To: "List for general do-it-yourself EFI talk" <diy_efi at diy-efi.org>
Sent: Thursday, April 24, 2003 1:28 PM
Subject: RE: [Diy_efi] Propane injection (KISS)


I would think that exposing the injector to a liquid at those temperatures
would end up killing it somehow, eventually... but then again, i don't know
what temperature propane at that pressure is... but I would believe you are
right, the propane is changing phase in the tubing. use tubing that is less
capable of transferring heat, then insulate it - stainless transfers heat
slower than mild steel, and a bunch slower than aluminum, you could then
maybe coat it in rubber or sandwich layers of insulating material... but
maybe some other material would be better than stainless.

the other thing to consider is this, the pressure drops slightly in the fuel
line when the injector opens, so it may be dropping enough pressure to allow
the propane to vaporize, rather than allow sufficient heat in through the
tubing to allow it to phase change.

or maybe more correctly, a combination of both?


-----Original Message-----
From: Mark Linder [mailto:mark.linder at verizon.net]
Sent: Thursday, April 24, 2003 12:08 PM
To: 'List for general do-it-yourself EFI talk'
Subject: RE: [Diy_efi] Propane injection (KISS)


I may be wrong, but it was my understanding that you NEVER wanted to
inject liquid propane.  From everything that I have read, only vapor
should be injected.

Mark



-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]
On Behalf Of A70Duster at aol.com
Sent: Thursday, April 17, 2003 7:56 AM
To: diy_efi at diy-efi.org
Subject: [Diy_efi] Propane injection (KISS)


I have some extra low-impedance injectors that I first applied 120 PSI
compressed air to and the injectors operated correctly.

Then I plumbed liquid propane (from a propane tank with the valve on the

bottom) to the injector and pulsed it.  Again the injector was working
correctly.

The problem was that a mix of liquid and vapor came out of the injector,
even
after a minute of pulsing the injector.  My guess is that the liquid
propane
is boiling in the transfer tube.  How does one stop this while keeping
things
simple?!?!  Insulate the line can help with heat intrusion and maybe a
liquid/vapor separator.

I don't want to add a fuel pump and regulator, I can live with tank
pressure
at the injector, but should find out the pressure that the injector
doesn't
open at.  And I want to inject liquid propane.  Phase change cools the
air
drawn in and I can deliver A LOT more liquid propane than vapor propane.

Why do I do this?  With propane at 110 octane and I can get it for $1.30
a
gallon, I could run on 87 octane gas for cruise and then kick in some
liquid
propane under heavy loads/WOT conditions.  This would first be applied
to a
turbo 4 banger, then who knows what is next..>:-)

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