Liquid Fueling Made Easy - Adv. Injectors For Liquid Fuel

[El-Kablooey]

It might be too difficult for the beginner to build, but by simply putting a spring in the design, instead of the manually adjustable screw thread, the mixing performance can be pushed to the max, for perfect mixing of any fuel over the entire throttle range.

Eric

Care to share some construction details?? The injector in the CAD rendering would be difficult for anyone to build, lol. Where does it come apart at?

Nice idea BTW, pure genius.

[Eric]

Yea ill get some construction plans posted. Most of the ones I made up are welded together and permanantly mounted in the engines.

I have a terrible back ache from hunching over priming stuff with the power sprayer all day, im going to go soak for a while and then I'll get some stuff posted.

Eric

[Eric]

Ok heres a paint layout for the permanantly mounted infinijector that I used on the 60 LB lockwood derivative which allows for super easy starting on a quick burst of compressed air.

Everything should be made from stainless. I will post a drawing for the fuel fitting / lock nut system, it basically is just a way to make your own fuel fitting and the lock nut keeps it from vibrating off. You could always weld the small fuel tube to the larger one, I just made the fittings so I can break everything down for transportation.

I like this type of injector layout for permanant injectors because its not taking up area in the intake, and the preheating effect is quite good, and the expansion keeps the injector from getting very hot.

With the injector pointing out of the intake, you can make the fuel gap either at a 90 degree angle or at any angle you wish facing back into the engine. 90 degrees works great for easy starting and superior mixing. A 60 - 30 degree gap should provide various degrees of self starting.

Even with the restriction the engine runs great on a vertical propane tank with vapor only. The system really does increase fuel efficiency quite a bit, and you can get quite a bit of power from the vapor only running.

I'll get working on a spring injector dimensioned builders layout, its the same general idea of building things in reduceable segments that can be added together to get the complex shapes that would normally not be able to be built.

The injectors can be made threaded, provided there is a locking nut mechanism for each thread, and you do not try to permanantly mount it, but I still reccomend welding everything if you stick to the plans or putting a tiny tack weld on the threaded sections that could later be ground off, but will keep things from unscrewing.

Eric

[milisavljevic]

Sweet! Not too complicated, but it covers all of the bases. I like the "silver bullet" style.

M.

[NickC]

doesn't a 90° spray still provide the most overall thrust? I thought you had said that in an e-mail once.

[larry cottrill]

Eric -

I like the gif - it explains a lot. You seem to be basically drawing a curtain of fuel clear across the velocity node, or just in front of it. I showed a similar thing in my SBIR submission to NASA, but it was a narrow fan of fuel projected from one side rather than a complete disk emanating from the center. I was using an ag spray nozzle in the prototype. It would have required failry high pressure to properly form the proper curtain shape, but I was going to do it with a 60 PSI Bosch fuel pump, which would have been more than adequate. The nozzle had an internal flow straightener leading to the orifice.

Your injectors look like a really nice offering (or perhaps, class of offerings). A very sensible specialty item, because they offer a definite improvement and few amateurs are equipped to make their own. Good luck marketing them!

L Cottrill

[Eric]

Thanks M. and Larry,
Its not something that I am going to make multiple identical units of before I get any orders, because the pulsejet market is just too slow, but if anyone is interested I can make these up pretty fast to order and for reasonable prices.

As with everything, its hard to make them really small, its not impossible but I would rather do as little precision machining of tiny stainless steel parts as possible! Anyone who has machined stainless knows why.

The fuel plane is the reason these work so well, the fuel is evenly distributed and mixing is innumerably better than any radial injector. I will have to remember to take a picture some night of one of them outside the engine.

The fuel mixing is so good that I have been able to move the injectors way farther back into the combustion chamber than normal, this can reduce power but really increase TSFC on some engines.

With it positioned vertical you can light it, crank up the fuel flow, and its like an upside down umbrulla of fire :)

With the angled ones, the mixing rate might not be as good, but the rosscojector effect is often worth it, especially with large engines. The large engines fire at a low enough frequency that mixing time is much higher, and still they mix fuel better than any radial injector. Medium and small engines really benifit from the 90 degree injection since the mixing rate is extremely high, for high frequency engines this really improves performance greatly.

One of the older injectors I tried before the "infinijectors" were basically a little vortex nozzle. You have a hole in the middle that forms a low pressure core, and around it a radial array of precisely angled fuel holes, that basically sucks in a massive volume of air and creates an extremely turbulent flame. Once you light it the flame will stay within 1" of the injector even at full blast, and create a bright blue flame about 3' long.


Eric

[Mark 42]

I wonder if a schrader valve (tire valve stem type) as used in
air conditioning systems would be a good starting point, at least
for a small engine?

Has anyone tried automotive fuel injectors (especially diesel injectors)?
I bet I could get some for free from a mechanic if they dicard old ones
instead of having them rebuilt. Or buy them cheap at one of those
"Pick your Part" scrapyards.

I'll have to check eBay too.

I might even try putting an old carburetor from a riding mower engine
in the intake pipe on the Advanced FWE, if I ever build one.

[Jim Berquist]

I obtained a 20lb chines from Adam. One of Eric's builds...

I too thought about the injectors from auto and diesel engines. Anything I found was way to bulky or plastic encased.

I like your idea of the schrader valve... The good ones have brass seats in place of rubber or plastic. Placed inside the end of a 1/4 line you may have something!

Edit: The carb idea has been tried I think.

Jim

[adam]

hey this spring thing in the injectors can act as a valve that saves fuel because on the exhaust cycle the pressure will close the gap by pushing foward on it since it is only under spring pressure right, and this will close it and not let any fuel spray out on that cycle rightl,? i know im probably just crazy, and think too much, but hey it might work'

[Jim Berquist]

Adam: I know squat about injectors. I have only used the Roscco type and straite type pipes. The powers to be , Eric, Roscco, Larry and Vernin would be the ones to ask. Eric offers a spring loaded purpose built injector of much the same design. Vernin just came up with one close and no spring. Larry I think has a contender. And of course there is the Rosccojector.

As the shcrader uses a cupped valve seat it is going to deliver the fuel sort of backwards unless deflected back forward! The others use a divergent cone in front.

The shcrader tire type may be too small for the 20lber. I will give it a shot. It may be good on your smoke system save you oil and deliver better mist?

jim

[adam]

well i have been sitting on my but all day and thought of an idea for a cheap easy way to build an infinijector that might work good for liquid fuel such as gasolin or diesel, say you have a copper tube 1/4 id and you wrap a commpression spring around it, one that fits snug'' and have it maybe a 1/4 inch long and have it wrap back over the other side of tubing that is a closed end, so i was thinking since a compression spring is pretty much like a tube, the gas can flow threw it and since the other side is capped off the fuel has nowhere to go but extend the spring and sqeeze out threw the sides as the spring stretches and it would distribute maybe a fine mist if liquide that is atomised by being forsed out of the spring walls as the spring is being streched from the pressure, would this idea work and if it did, would it work pretty good since it seems like it would distibute a spray of fuel radialy several times from the shape of the spring, eric since you no all about good infinijectors do you think this idea would work good?

[Irvine.J]

Its interesting, best bet is to try it, I'd silver braze it on though, otherwise you'll have a high velocity dart shoot off and poke something important :-D
At many hardware stores are those hand pump up spray bottles, a brass tip off one of those might be the ticket also, theres lots of stuff that will work nicely for an engine that big.

[Irvine.J]

Hey adam, why not also just try a normal spray injector if your going to run gasoline, one like this...

http://cgi.ebay.com/Misting-Nozzles-on- ... dZViewItem

I'm not sure what kind of pump you intend to use, a normal automotive will be fine, just check your gasoline flow rates with eric. I think though the flow rates are based on standard water pressure in most of these cases, but be careful the flow rates don't mean a Lock over a certain pressure.
(even though you increase the pressure your flow rate wont increase)

Anyway, these guys are usually hell cheap, so experiment with a couple till you find one that suits. A quick bit of web searching should yield every
spray pattern in the known universe.
Good luck man!

[Jim Berquist]

I should try to do something like that after I get a handle on starting the 20lder with propane.

Jim