NG / Propane dosing on Listeroids

[veggie]

I fabricated a fitting for the inlet of my Listeroid to allow Gas dosing.
I know there are a few other members on the forum who have already
done this and I would like to know if my Gas nozzle is acceptable.
The nozzle is a stainless steel tube crimped at one end with 4 small holes drilled
in the middle of the air path. Upstream of this, the system has a needle valve to control flow and a regulator to manage pressure.
The needle valve can be adjusted to throttle the flow through this nozzle.
Has anyone used simple holes for this service compared to the angled nozzles used in automotive nitrous injection.
Will it work ?

cheers,
Veggie

[Carlb]

That should work fine.  I just used a 1/8" pipe nipple with a slash cut threaded into my inlet elbow and it works fine.  I too use a simple needle valve to regulate the amount of nat gas injected into the engine.  I have mine set for an average 1500 to 2000 watts.   I marked the rack with a small scribed line with the engine at no load @60hz, I then put a 1500 to 2kw load on the engine and adjusted the needle valve to close the rack back to the idle position.  When the load drops the engine will start to miss as the governor tries to close the rack too far but it isn't a problem. When the load increases over 1500 to 2k the rack just pulls open to add more diesel.  i chose 1500 to 2k because that is what my average load is.  Using this method with loads of 2k or less the rack is open just enough to keep the engine running the rest of the fuel is natural gas.  

youtube link below

https://www.youtube.com/watch?v=AwPPui8Fyi0

Carl

[BruceM]

Marvelously simple and safe setup, Carl.  I would love to see your fuel(s) data.  My typical load range is the same as yours, and I'd like to burn mostly propane.

[sailawayrb]

Similar setup to Carl and can burn either natural gas or propane as indicated.  Primary fuel is SVO and mostly burn low level of propane to eliminate carbon buildup and associated maintenance.  Use a vacuum switch to close solenoid and stop flow as safety precaution should the engine shutdown.

http://mbryner.fatcow.com/listerenginegallery/main.php?g2_itemId=351

[BruceM]

Thanks for the look at your setup, sailawayrb.  As I sometimes run my air compressor alone (generator unbelted) on my 6/1 when I have a big wood project in my shop (all air power) so a crankcase vacuum controlled gas (diaphram) valve might be my best solution- no power needed.  Pity the intake manifold vacuum can't be reliably used to regulate propane flow as in a gas engine conversion kit. 

[sailawayrb]

Right Bruce, a constant diameter intake pipe doesn't facilitate using it to regulate the natural gas flow.  Since you can't run a high percentage of propane anyhow, just using the mechanical governor is a good approach for propane.  Now if you wanted to push the near 100% boundary with natural gas, I could see how using a small constant flow of diesel or SVO and a system that throttled the natural gas might have some advantages.  If you replaced the standard intake pipe with a venturi section and the appropriate pressure ports, you could build a throttling system that could regulate the natural gas flow.

[buickanddeere]

You can supply a diesel with as much NG as you want in a pilot injection application.
Problem is LP has too low of octane to use in a pilot injection or carburated application with 16 to 1 compression.
The lower explosive limit of propane is 3.2%  by mass or  2.1% by volume  depending on who you ask.
The ideal LP airfuel mixture is 6.4% by mass or 4.2% by volume.