Fuelling system (really need help!)

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koko
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Fuelling system (really need help!)

Post by koko » Mon Feb 23, 2004 2:46 pm

I'm building my first Pulse Jet and i have no idea how to fuel the jet. From my understanding, the concept of pulse jet engine is similar to normal piston engines which means there are intake, combustion, power and exhaust cycle. My question is, if i inject the fuel directly into the combustion chamber, how do i stop the fuel from going into the chamber except for the intake cycle. I'm using inverse valve as seen on www.ponnet.com They inject directly into the combustion chamber but i still wondering whether the fuel is continuosly injected or only during the intake cycle. I'm planning to use LPG for fuel and air-conditioner nozzle. Any diagrams on the fuelling system would be greatly appreciated.

Rescyou
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Fuel

Post by Rescyou » Mon Feb 23, 2004 7:04 pm

You manually control the fuel flow in the direct inject method so you must adjust it to obtain the right balance.

The way I've done it in the past is to determine the LEL and the UEL of the fuel and set the regulator to an average value between the two.

LEL = Lower Explosive Limit
UEL = Upper Explosive Limit

Get it running and decrease the fuel pressure till the thing no longer supports combustion to determine your LEL then start it again and increase the fuel pressure till the thing no longer runs to determine UEL

Now I don't know that the average between the LEL and UEL is optimum, but I think it is.. I guess if you really wanted to get technical you could install an O2 sensor from a car and mess with it.

The pressure within the jet will overtake the pressure of the fuel in the combustion phase so the jet won't have constant fuel coming into it but runs so fast that it seems like it's constant fuel pressure.. That pressure is the same thing that slams the petal valve closed.

Links to some fuel systems:

http://home.earthlink.net/~famcaine/pul ... c481752816


This is Larry C's jet mag and it describes the construction/use of Bruce T's bladder tank design. (The Good Bruce, not the Evil Bruce)

http://www.jetzilla.com/Vol01Num01/jetZ ... #Article_2


S.
The mind of a man is the man himself.

Viv
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Re: Fuel

Post by Viv » Mon Feb 23, 2004 8:00 pm

Rescyou wrote:This is Larry C's jet mag and it describes the construction/use of Bruce T's bladder tank design. (The Good Bruce, not the Evil Bruce)S.
Just how much would it cost to bribe Kenneth in to letting me alter the two Bruces membership names?

Oh god thats just so going to stick!

Viv:-)
I may just die laughing:-0
"Sometimes the lies you tell are less frightening than the loneliness you might feel if you stopped telling them" Brock Clarke

Viv's blog

Monsieur le commentaire

Mark
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The Great Leslie and Professor Fate

Post by Mark » Tue Feb 24, 2004 1:40 am

Viv wrote:
Rescyou wrote:This is Larry C's jet mag and it describes the construction/use of Bruce T's bladder tank design. (The Good Bruce, not the Evil Bruce)S.
Just how much would it cost to bribe Kenneth in to letting me alter the two Bruces membership names?

Oh god thats just so going to stick!

Viv:-)
I may just die laughing:-0
I would liken the two Bruces to the move, "The Great Race", starring Tony Curtis as the Great Leslie, the good guy and, Professor Fate, Jack Lemmon/ Bruce Simpson as the "bad" scheming guy. It was a funny movie about a race car race around the world. Professor Fate was quite flawed but likable in some strange way.
http://www.dvd.reviewer.co.uk/reviews/r ... 4&User=627
Mark

Mark
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Joined: Sat Oct 11, 2003 10:14 pm

Re: Fuel

Post by Mark » Tue Feb 24, 2004 3:36 am

Rescyou wrote:You manually control the fuel flow in the direct inject method so you must adjust it to obtain the right balance.

The way I've done it in the past is to determine the LEL and the UEL of the fuel and set the regulator to an average value between the two.

LEL = Lower Explosive Limit
UEL = Upper Explosive Limit

Get it running and decrease the fuel pressure till the thing no longer supports combustion to determine your LEL then start it again and increase the fuel pressure till the thing no longer runs to determine UEL

Now I don't know that the average between the LEL and UEL is optimum, but I think it is.. I guess if you really wanted to get technical you could install an O2 sensor from a car and mess with it.

The pressure within the jet will overtake the pressure of the fuel in the combustion phase so the jet won't have constant fuel coming into it but runs so fast that it seems like it's constant fuel pressure.. That pressure is the same thing that slams the petal valve closed.

Links to some fuel systems:

http://home.earthlink.net/~famcaine/pul ... c481752816


This is Larry C's jet mag and it describes the construction/use of Bruce T's bladder tank design. (The Good Bruce, not the Evil Bruce)

http://www.jetzilla.com/Vol01Num01/jetZ ... #Article_2


S.
That was a good reread of older postings. I enjoyed the articles on fueling.
Mark

Mike Everman
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Post by Mike Everman » Tue Feb 24, 2004 5:01 am

Yeah, that was good, thanks!
Mike
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Mark
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Post by Mark » Wed Feb 25, 2004 5:04 pm

I wonder if someone has taken apart a Cline regulator to see just how it works, or if someone could make one easily enough with the diagram.
Mark

cbromano
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Post by cbromano » Fri Feb 27, 2004 4:06 am

Is a cline regulator the type used on propane tanks?
I don't wish to know everything.
I just wish not to be ignorant.

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