Carburetor Diaphragm Movement Detector and its system

As you gents may know there are several types of carburetors, diaphragm type, gravity fed type, and injection type(perhaps this may not be classified to the carburetors though). I used to have a lot of discussion at a forum where we tinker small engines of saws, on a theme that how a diaphragm acts in operation. Does it move constantly along with the movement of piston that goes up and down in every cycle of the shaft sits in the middle of mechanism ?, or it keeps moving until it comes to a certain spinning speed and stays/sits still in higher speed than this?

So I made this system to see how it acts in operation from lower spinning speed when it idles to some higher speed like 7000rpm.

The total system looks like this;
Attachment 23114
at the left you see a saw sitting with some attachments on the top cover, which is a displacement detector unit also shown below.

Within the small blue plastic cylinder there are a couple of coils,
Attachment 23121

and this coil emits magnetic force from the black part outward.
Attachment 23122

Showing a illustration to the way detecting the movement.
Attachment 23123



(to be continued...)

Chy

It's always fun to know some hidden truth coming out unveiled, a diaphragm has been keeping moving even in high spinning!!!

For each graph the upper column shows the timing signal from the motor, every high peeks in the blue curve means voltage peeks given by the pulser coil I have given to the main coil unit.
The orange curve in the lower column shows the movement of a diaphragm.

Illustration_03_1991rpm
Attachment 23133

Illustration_04_4056rpm
Attachment 23134

Illustration_05_7472rpm
Attachment 23135

Chy

Showing each part below,

this detector set on the motor,
Attachment 23141

signal amplifier upper in the middle,
voltage divider lower left, which is used to optimize the voltage from the pulser coil. (to be frank, I reeled the wire a little too much for this pulser coil, better less than 10 times perhaps.)
Attachment 23142

Attachment 23148

analog-digital converter lower left, like the one you might have used for electric guitars.
Attachment 23143

Winding wire to make a pulser coil.
Attachment 23144

Setting the pulser coil done.
Attachment 23145

How it works;
Attachment 23146

Illustration added to show how the detector/sensor works;
Attachment 23147

Chy

Chy_farm,

Great job. You must have had a lot of fun doing this. I have also made a multitude of simple test instruments for measuring the things that go on in engines which most people don't bother with. I expect that you have several more ideas to show us.

I have one question. How did you attach the metal plate for the sensor to the diaphram? Was it already a part of the diaphram or did you have to add it? If you had to attach it then it would have affected the results.

Quote:

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Originally Posted by tonyfoale

Chy_farm,

Great job. You must have had a lot of fun doing this. I have also made a multitude of simple test instruments for measuring the things that go on in engines which most people don't bother with. I expect that you have several more ideas to show us.

I have one question. How did you attach the metal plate for the sensor to the diaphram? Was it already a part of the diaphram or did you have to add it? If you had to attach it then it would have affected the results.

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Good afternoon Tony, and thank you for your comment. Glad to know you have a lot of knowledge and experience on this thing.
It's amazing that you have such a deep insight about that point Tony, definitely Yes.

When I put another iron round plate on the same place where the original aluminium plate has been sitting, namely I replace the original plate(they call it a metering plate, if I remember correctly), the result was a tad different to the one I posted above.
I think you may be looking at one feature these graphs show, that is the wave form shown in orange in each of these lower column.
They are nearly sine curbs.
This means that the metering plate was moving in one single movement, or in the basic frequency that the motor-spinning speed permits.
And this also means that this metering plate has been made to have the center position/hole for the metering pin sit right in the center of the round shape of this metering plate. Perhaps this might sound funny that I mention this thing to be some special thing, but it must be one of the very important points about the carburetor setting thing.
(to be continued...)

Understood. I have had little experience with diaphram or pumper carbs and I had forgotten about the metering plate and pin.

You might be interested in some carb experiments that I did a while back to get a visualisation of the mixing. Here are a couple of videos;

https://www.youtube.com/watch?v=XlA1AeAX8Bk

https://www.youtube.com/watch?v=O0fwQTaUPrU

chy_farm,
That is a very interesting and noteworthy experiment. Was your sensor a LVDT?

Quote:

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Originally Posted by owen moore

chy_farm,
That is a very interesting and noteworthy experiment. Was your sensor a LVDT?

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Good morning Owen, thank you for your comment. It seems like it is, but I did no know this word LVDT though, lol.
Chy

chy,
What I was referring to was a linear variable differential transformer. Sorry for the confusion and the nomenclature. I like what you have done.
Best Wishes
Owen Moore

Quote:

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Originally Posted by owen moore

chy,
What I was referring to was a linear variable differential transformer. Sorry for the confusion and the nomenclature. I like what you have done.
Best Wishes
Owen Moore

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Owen,

I think that Chy's sensor could more accurately be considered analogous to an old style magnetic telephone ear piece or microphone.

Quote:

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Originally Posted by chy_farm

Good morning Owen, thank you for your comment. It seems like it is, but I did no know this word LVDT though, lol.
Chy

---

Quote:

---

Originally Posted by owen moore

chy,
What I was referring to was a linear variable differential transformer. Sorry for the confusion and the nomenclature. I like what you have done.
Best Wishes
Owen Moore

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Good evening Owen, many thanks. I looked for some informative site on this tool, and got it means. LVDT Seems it gives us geometry data of the linear movement of the core inside the coil housing, whereas this detector tells the axial movement of inductive material outside of this unit of coils when both of the material and the coils sit in the same axis. Thanks again,
Chy

Quote:

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Originally Posted by tonyfoale

-----
You might be interested in some carb experiments that I did a while back to get a visualisation of the mixing. Here are a couple of videos;
youtube.com/watch?v=XlA1AeAX8Bk
youtube.com/watch?v=O0fwQTaUPrU

---

Good evening Tony, these video are fun to see! Especially the first one is very impressive to me. Many thanks, appreciate your kindness and quest for science!
Chy

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Thanks chy_farm! We've added your Carburetor Diaphragm Monitoring System to our Carburetor category,
as well as to your builder page: chy_farm's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-carburetor-diaphragm-monitoring-system"> <img src="/uploads/212656/homemade-carburetor-diaphragm-monitoring-system.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-carburetor-diaphragm-monitoring-system">Carburetor Diaphragm Monitoring System</a> <span> by <a href="http://www.homemadetools.net/builder/chy_farm">chy_farm</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/carburetor'>carburetor</a>, <a href='http://www.homemadetools.net/tag/measurement'>measurement</a> </div> </div> </div> </div>
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Using this detector, I tried to see how the weight of metering plate means to the movement of it in operation. I thought some comparison could mean something about them.

This is one of the original diaphragm with a perfect round metering plate on it. Some holes are cut out there. It seems that these holes help to decease its weight a little, but it also seems to me that opening holes is not the least thing to do for this part. Later I got to know how it concerns to the movement.
Attachment 23287
This weighs 0.73gs, thickness is 0.2mm.

First I had and assumption that the weight of metering plate means more for higher spin speed, since they have to repeat ups and downs so many times in a second, lol. This thought of mine lead me to try out another homemade metering plate that weighs lighter than the original.
Attachment 23288
This weights 0.63gs, 0.10gs lighter than the original.

This homemade one was made from a piece of alu plate. Thickness decreased to 0.15mm by mallet work, was 0.3mm originally. Why mallet work? Yes I wanted to give this plate some hardening cause it vibrates with some pressure.
Attachment 23289

The weight of this plate itself was only 0.12gs.
Attachment 23290

(to be continued...)

Chy

Congratulations chy_farm - your Carburetor Diaphragm Monitoring System is the Homemade Tool of the Week!

This is a clever, complex, and original tool build, accompanied by a good bit of information and data. It will be interesting to see the follow-up posts to this build, as well as any related tools.

Difficult week to win; we had a lot of highly-rated tools across a wide range of disciplines - machining, welding, woodworking, luthiery, and automotive.

Some good picks:

Index Drilling Setup by xynudu
Quick Clamp by Bongodrummer
Curved Routing Jig by starkw1
Pneumatic Tool Organizer by Eloy Workshop
TIG Wire Feeder by chy_farm
Toe Jack by thehomeengineer
Reamers by Christophe Mineau
Bandsaw Blade Soldering Fixture by thehomeengineer
Saw Bench Casters by somyunguy
Slitting Saw Arbor by Canobi
Cyclone Separator by chy_farm
Mill Stop by thehomeengineer
Tube and Cone Press by chy_farm
Belt Sander by garage nut
Machine Dogs by thehomeengineer
Dummy Load by chy_farm
Inverted Jack Mounting by Tuomas
Flute Milling Fixture by Christophe Mineau
Vacuum Desiccator by chy_farm
Table Saw Repair by tonyfoale
T Stake Holder by Steved53
Welder Dolly by chy_farm


chy_farm - we've added your tool entry to our All Homemade Tool of the Week winners post. And, you'll now notice the wrench-on-pedestal award in the awards showcase in your postbit, visible beneath your username:

https://www.homemadetools.net/forum/...OfTheWeek4.pnghttps://www.homemadetools.net/forum/...eWeekIcon4.png

You'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, or bitcoin. Please PM me your current email address and gift card choice and I'll get it sent over right away.


Congratulations and well done! :thumbsup:

Thanks for the response, chy,
While we are on the subject of diaphragm carburetors; do any of you fellows know of a source in the US where one could buy diaphragm material of various thickness's and compounds?

Quote:

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Originally Posted by Jon

Congratulations chy_farm - your Carburetor Diaphragm Monitoring System is the Homemade Tool of the Week!--------

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It is truly a great pleasure to me to be able to get this award. Thank you very mush for your likes!
Chy

Quote:

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Originally Posted by owen moore

Thanks for the response, chy,
While we are on the subject of diaphragm carburetors; do any of you fellows know of a source in the US where one could buy diaphragm material of various thickness's and compounds?

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Good evening Owen, very sorry to say that I do not know much about the original manufacturer of my membrane. I got this from a local distributor who said this one is a US made but did not tell me who.
Regret that I can not be of any help to you on this. Hope you can find a better information.

Chy


p.s. Please let me informed of the information if you got to know some maker or distributors there. thanks in ahead.

Congratulations Chy, Well Deserved! :clapping: Look forward to the continuation of the project.

:hattip: PJ