Author Topic: Vapor Carburetor Fuel Tank Experiments  (Read 9437 times)

Offline cfellows

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Vapor Carburetor Fuel Tank Experiments
« on: March 21, 2013, 06:15:25 PM »
While certainly not as authentic as carburetors in model engine making, I have had pretty good success using vapor fuel tank carburetion on my model IC engines.  Vapor Fuel Tanks have been used for smaller engines in the past and I heard that Ford Motor Co had actually done quite a bit of research on the use of vapor fuel carburetion in the early days.  Jan Ridders has popularized the vapor fuel tank on most of his model IC engines, making attractive tanks that work well for him. 

The vapor fuel tanks are very easy to make and pretty much work with little or no adjustment.  Following Jan's examples, I have added an adjustable mixer that allows the introduction of more or less air with varying degrees of success.  My experience has been that my vapor fuel tanks produce a mixture that is barely rich enough in the best of circumstances and hardly require any adjustment to make the mixture leaner.  In addition, the vapor carburetion method is extremely sensitive to fuel level in the tank, partly I expect because of the surface area presented.

So, I'm trying a different setup that hopefully will resolve some of the above problems.  I have reasoned that a flat, rectangular tank would give me larger fuel surface area resulting in more fuel evaportation and would make the fuel level less of an issue because the surface area would remain unchanged with differing fuel levels.

I found a nicely shaped bottle in my better half's perfume collection, but, unfortunately, no amount of pleading or wooing would cause her to relinquish it, even though it was nearly empty.  So, looking on Ebay, I found a number of such empty bottles of the same brand.  For those who are interested, it is called Red Door made by Elizabeth Arden.  Here are some pictures:



Without the Lid...



The other red part pulls off with very little coaxing...



And here's what it looks life after cutting off the top with my Harbor Freight Wet Tile Saw...



The wet tile saw works very well.  The trick is to go slow and keep the bottle straight as you go.  I just pressed the bottom against the included saw fence as I pushed it past the blade.

As an added note, if you decide to go this route, you better be prepared to explain to the spouse why your hands, clothes and shop smell so good!

Next I'll machine a new end for the bottle and add some plumbing.  Stand by...

Chuck
« Last Edit: March 21, 2013, 06:20:24 PM by cfellows »
So many projects, so little time...

Offline dsquire

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #1 on: March 21, 2013, 07:57:36 PM »
Chuck

Inquiring minds want to know. Did SWMBO believe you explanation? Hope that she did, cause it could be cold in the dog house.  :lolb: :lolb:

Cheers  :cheers:

Don
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Offline b.lindsey

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #2 on: March 21, 2013, 08:13:03 PM »
Looking forward to more on this Chuck....but serioiusly...people really sell empth perfume bottles on ebay??  Who would have though there would even be a market for such...particularly amongst a home shop machinist group  :o

Bill

Online Jo

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #3 on: March 21, 2013, 08:58:38 PM »
I could come to your rescue here: I will let you buy me the purfume, I will then generously use it up for you  :-* and then provide you the empty bottle.

How does that sound?  ;D

Jo

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Offline ths

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Vapor Carburetor Fuel Tank Experiments
« Reply #4 on: March 22, 2013, 02:45:05 AM »
Hi Chuck,

I'm with Bill when it comes to finding out what people sell on eBay. What search words were used?

Hugh.

Offline cfellows

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #5 on: March 22, 2013, 02:59:35 AM »
I could come to your rescue here: I will let you buy me the purfume, I will then generously use it up for you  :-* and then provide you the empty bottle.

How does that sound?  ;D

Jo

P.S. I know it is not castings or machine tools but there is another side of me  ;)

Thanks for the offer, Jo, but I already have a volunteer here at the house!   :LittleAngel:

Hi Chuck,

I'm with Bill when it comes to finding out what people sell on eBay. What search words were used?

Hugh.

Well, it was the wife's perfume bottle that started the search so I just did a search for red door perfume bottle and several popped up.  You can also do a search for empty perfume bottle.  I also did searches for small square bottle.  Got lots of results, but the red door perfume bottle won out.

Chuck
So many projects, so little time...

Offline ths

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Vapor Carburetor Fuel Tank Experiments
« Reply #6 on: March 22, 2013, 08:13:19 AM »
Well blow me down, there's heaps of 'em, great prices, great shapes!

Hugh.

Offline cfellows

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #7 on: March 22, 2013, 09:16:39 PM »
Here's the results of my perfume bottle fuel tank...

http://www.youtube.com/watch?v=EsJie5oVgGg&

The greater surface area of the tank makes the engine run richer.  In fact, if I close the air mixer completely, the engine will stop running. 

There seems to be a lot of different dynamics in determining how the vapor fuel tanks operate.  I'm going to continue to experiment with some different designs, but for now, I've got the engine apart so I can paint it and make a base for it.

Chuck
So many projects, so little time...

Offline zeeprogrammer

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #8 on: March 22, 2013, 10:32:50 PM »
Very sharp Chuck. I can't wait to see it painted up.
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chuck foster

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #9 on: March 22, 2013, 10:41:19 PM »
very nice running engine chuck.  :ThumbsUp: :ThumbsUp:
i have run a few of my models with the vapor carb , but i used just a small mason jar for the tank. yours is much more interesting.
there is a guy on a website called smokstak    http://www.smokstak.com/   , he goes by the name nar
he got me started on using the vapor carb as he uses this type of carb on all his models.

thanks for the write up   :happyreader:

chuck the northern one
« Last Edit: March 22, 2013, 10:49:01 PM by chuck foster »

Offline AussieJimG

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #10 on: March 23, 2013, 12:01:35 AM »
I found this on YouTube. It looks interesting.


Jim

Offline gbritnell

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #11 on: March 23, 2013, 03:20:35 PM »
Boy it sure runs nice on this new tank Chuck. Having followed these type tanks since I saw Jan Ridders using them it sure looks like they are the best way to go, especially with hit and miss type engines that don't need a lot of throttle control.
gbritnell
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Offline cfellows

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #12 on: March 23, 2013, 08:16:28 PM »
Boy it sure runs nice on this new tank Chuck. Having followed these type tanks since I saw Jan Ridders using them it sure looks like they are the best way to go, especially with hit and miss type engines that don't need a lot of throttle control.
gbritnell

Thanks, George.  These vapor tanks are a lot less finicky than carburetors.  Throttling does present a problem and I suspect there is a limited amount of power you can get from a vapor tank.

I found this on YouTube. It looks interesting.


Jim


Thanks, Jim, lot's of research has gone into the vapor carburetion system.  There are lots of parameters and dynamics involved.  The main parameters are surface area and temperature.  These two parameters determine how fast you can evaporate the fuel.  The other parameters are volume of head space, which determines how much vapor you can store between power strokes and the path of the air from the inlet to the outlet which leads to the engine.  The path is important because you want to be drawing vapor into the engine, not fresh air from the air inlet.  I suspect that the two reasons fuel level in a tubular tank affects the outlet mixture is because increased head space allows more fresh air to get to the outlet and the surface area gets smaller as the fuel level falls.

very nice running engine chuck.  :ThumbsUp: :ThumbsUp:
i have run a few of my models with the vapor carb , but i used just a small mason jar for the tank. yours is much more interesting.
there is a guy on a website called smokstak    http://www.smokstak.com/   , he goes by the name nar
he got me started on using the vapor carb as he uses this type of carb on all his models.

thanks for the write up   :happyreader:

chuck the northern one

Thanks, Chuck.  I need to go look over that thread to see what I can learn.

Very sharp Chuck. I can't wait to see it painted up.

Thanks, Zee, the wood base is built and the second coat of varnish is drying.  The engine is apart and painted.

Chuck
So many projects, so little time...

Offline cfellows

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #13 on: March 23, 2013, 08:23:30 PM »
While the paint and varnish are drying I'm moving on with my next fuel tank design.  This one will be aesthetically more pleasing.



The glass part is about 1 1/2" OD and 4" long.  I used my tile wet saw to cut the top off.  The original bottle was about 7" tall and has pretty thick walls.  I cut a groove inside the aluminum top and inserted a 1 5/8" x 1 1/2" o-ring.  The bottle is a snug fit inside the o-ring and doesn't leak any fuel.



I will need a tail piece to keep the bottle from working it's way out, but will not need any clamping pressure to seal the container.  Still have some work to do before this one is finished.

I have a third tank I also want to try.  It will be made from a 1 1/2" square bottle that will be about 4" long.  With the square cross section, the surface area of fuel will not decrease as the fuel level falls.

Chuck
So many projects, so little time...

Offline ScroungerLee

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Re: Vapor Carburetor Fuel Tank Experiments
« Reply #14 on: March 23, 2013, 08:55:48 PM »
I will be interested to see what you find out regarding the temperature of the tank.  I have found a thin wall metal tank will get cold enough that the engine won't run, then once it warms up again the engine will run fine.

 I thought at first the volatiles (if that is the word) from the fuel were being used up first, but since it runs again when warmed up I guess I was wrong.

Lee
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