[Vwdiesel] Diesel working on liquid propane

[James Hansen]

Doyt, that phase change might be a benefit if you can increase the intake
air charge density with it. Might take a bit of clever with intake valve
timing and injector location, but I can see how it might be used.   I would
think injecting most flammable liquids straight into the prechamber area
would ignite similarly regardless of the heat of vaporization, and flame
front travel should also be similar too, unless you do something to
accelerate or decelerate it, like fumigate or water inject it.  Cylinder
pressure at tdc should be near what you get during a compression test, but,
just a guess, around 1100C or so.
-james


-----Original Message-----
From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com] On
Behalf Of Doyt W. Echelberger
Sent: October-12-10 4:18 PM
To: vwdiesel at vwfans.com
Subject: Re: [Vwdiesel] Diesel working on liquid propane

I re-viewed some of the Bob Hoover sermons and emails on his propane 
project. This one surprised me:

"Actually, converting a water-cooled engine to run on propane is
dead-simple.
Once I get the bus and bug running to my satisfaction I'll probably try my
hand at a propane-powered trike (!) and a turbo-supercharged propane-powered
1600cc Datsoon pickup.  Then there is the attractive prospect of direct
fuel-
injection using propane..." Bob Hoover, Fri, 19 Dec 1997.  (my bolding and 
underlining.)

It certainly isn't impossible, and all our diesels get fueled by injector 
pumps.

One downside that I see is that when the injected liquid propane goes 
through its phase change to a gas, it makes a lot of heat disappear. That 
phase change would take place very near the injector tip. That space would 
need a glow plug that could deal with that situation, to get things started.

The other things I wonder about are (1) what pressure is required to keep 
propane a liquid at room temperature, (2) What is the pressure and 
temperature in the cylinder of a diesel engine at the moment a charge of 
propane should be injected during compression, (3) would that be sufficient 
to  cause combustion without a spark plug, (4) and would the resulting 
flame front be slow enough to provide an efficient push to the piston.

Also, liquid propane isn't a very good lubricant for the working parts of 
an injector pump.

This is an interesting thread.

Doyt


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