Propane Motor Fuel Injection

[Johnny]

At 12:03 AM 12/4/95 -0500, you wrote:
>Pressurizing the tank with nitrogen would be an effective tactic as long as
>the propane in the tank was liquid and the pickup was below the liquid level.
> A baffled tank would help this quite a bit if obtainable.  Using the
>nitrogen to maintain a high constant pressure would increase the likelyhood
>of having liquid at the pickup.  Venting the nitrogen prior to filling would
>remove the filling problem, although it would be worth calculating the volume
>of unburned hydrocarbons you would be putting into the atmosphere, this would
>be traded off against the garbage you didn't put into the air by burning
>gasoline.

This has crossed my mind. I thought of running 2 tanks in the vehicle. Run
one all the way down till all there is, is nitrogen. Then switch to the
other one, and fill the empty one up. It would seem that the nitrogen
pressure over the propane would keep it in a liquid state all the way to the
end allowing you to effectivly run it all the way out. Then when you purged
the tank for filling, all you would get out is nitrogen... maybe a trace of
propane, but not enough to worry about. The tank would have to be made
special (I do these myself) and it would have a little baffling and a sump
just like any liquid fuel tank does. The pickup would be at the bottom of
the sump of course. The nitrogen would probably come from a 3000 psi scuba
bottle, regulated to 300 psi or so. Would have to see what it cost for the
nitrogen, but it would seem that it wouldn't add up to that much.

>I don't have any experience with, but have read about the N2O guys using
>pulsed solenoids to ramp up the flow rate to soften the initial hit.  You
>might look at the stuff they are using as far as solenoids and distribution
>systems.  It may be possible to build a TBI system with their stuff.  
>
>The computer compensation for pressure scheme sounds good.  You could use a
>regulator to cut down on some of the dynamic range.

I think it will take both a pressure head (like the N) and a liquid
regulator (set to about 150psi or so) to get it to be stable enough. Then
with the computer compensating for the small fluctuations that still exist,
I think it is do-able.

>For real power or efficiency with propane, the compression needs to be
>increased.

That's for sure. I have a set of 12.5:1's sitting right here. I guess I
should start building the prototype engine and by the time I get done with
the heavy stuff, the rest of you guys will have the '332 stuff just about
ready for me to come and vulture on.

-j-