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Discussion Starter · #1 ·
This would of course require a fair amount of electrical knowledge, but ....



We've all wanted some sort of gas gauge to measure the remaining fuel level. How about if you had a way to measure how much fuel had been used?



I'm thinking about a little piezo transducer tht emitted a pulse into the tank then computed how much empty space there was by the natural audio resonance pulse that was returned.



Kind of like blowing across a pop bottle every now and then as you were drinking it.
 

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I was trying to think of a pressure sensor. Gas has a weight along with gravity and the sensor could be put on the outside of the petcock. But then you would need to know absolute weight of a full tank in pressure terms.



Probably many ways to do this with the right time and money.
 

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I think that perhaps with the engine drawing in fuel flow at the petcock it may affect any gravity reading taken there. Perhaps an individual sensor on the other side of the tank would be a more accurate reading. I may be wrong though, im used to working on fuel injected diesel engines that flow huge amounts from the tank pickups and return most back to the tank.



Then again if you were to make a sensor that calculated absolute weight im thinking it would not read accurate at higher altitudes unless there was an ecm to calculate absolute weight with the asistance of a barometric pressure sensor.



Ofcourse that is if im thinking of the term absolute weight properly. On the engines I work on the boost pressure sensors are a calculated absolute sensor, meaning that if you monitor that sensors reading with the engine off it reads 0 psi, when in reality its reading about 16 psi atmospheric.



This is one of them nerdy tech subjucts that I get into.
 

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I think the problem is doing it without cutting a hole. It would be nice if we could just weld on another bung and screw in something.



I always think about the Kawasaki fourwheeler I had with the manual gauge on the tank. Just like old boat gas tanks.
 

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A glass porthole in tank with a sensor is a good way to go beats using the boat flare i keep under my seat for emergencies!!



FlashBOT
 

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Hay the dog in my avatar is named Bandit! After looking at the gauge mentioned its rather long and would have to be mounted where the hump inside tank over frame does not interfere with it! These are common with boat fuel tanks. I carry an aluminium fuel bottle that holds a litre when on long trips.
 

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After looking at the gauge mentioned its rather long and would have to be mounted where the hump inside tank over frame does not interfere with it! .


Yes that would be a problem but may be able to be bent to an angle to miss the hump and still function and or extended to go right down to the bottom on one side.
 

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Discussion Starter · #13 ·
The hump is definitely a problem as would be the calculus involved in trying to figure out where you were at from a simple level. The pressure method would involve far too many variables as you could only measure a height level, it would take a calculus model of the tank to deduce anything useful.



With my idea it would give you a fairly close approximation of the volume of air space left in the tank and wouldn't be affected by being on the side or center stand.



Guess I'll come up with some basic ideas in theory and a proposed circuit, then enlist the help of a bunch of electronics nuts in another forum I participate in to get their opinions. It could be tht a hole wouldn't be necessary if you could figure out a mounting method that would allow you access to it to swap batteries from time to time. Since it would only have to "test fire" on a very occasional basis, and since modern electronics is easy enough to put into a sleep mode a 3V lithium coin cell could last for years.



I think you could interface with the circuit via some sort of magnetic coupling with coils for the inside and outside electronics hidden somewhere "on the hump" so to speak so they wouldn't be visible.
 

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I think you could interface with the circuit via some sort of magnetic coupling with coils for the inside and outside electronics hidden somewhere "on the hump" so to speak so they wouldn't be visible.


I had a look around and one suggestion,for safety,was to fit a traducer/mic/piezoelectric of some sort under the tank as an input device to detect the resonance of the tank at different levels of fluid by volume?
 

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My grandpa when checking the gas on his farm all tractor would use a wooden stick. Just seems to make sense.
 

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Discussion Starter · #16 ·
I had a look around and one suggestion,for safety,was to fit a traducer/mic/piezoelectric of some sort under the tank as an input device to detect the resonance of the tank at different levels of fluid by volume?


That is also a possibility, however I somehow doubt a 3V lithium circuit, if properly built and sealed from the gas, would ever create a spark. Besides that a lot of people don't understand that if the air/fuel mixture isn't almost perfect it won't ignite to begin with.



Hmmm, resonance from the outside. Good thing I've got an extra tank, at least until I paint it but then I'll have the other. Thought I had all the rust etched out of my spare then of course when I went to protect it by sloshing around a strong mixture of LPS + water some new big chunks appeared. I may have to go the electrolysis route to be darn sure I've got this thing clean and still fliter the heck out of it.
 

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That is also a possibility, however I somehow doubt a 3V lithium circuit, if properly built and sealed from the gas, would ever create a spark. Besides that a lot of people don't understand that if the air/fuel mixture isn't almost perfect it won't ignite to begin with.



Hmmm, resonance from the outside. Good thing I've got an extra tank, at least until I paint it but then I'll have the other. Thought I had all the rust etched out of my spare then of course when I went to protect it by sloshing around a strong mixture of LPS + water some new big chunks appeared. I may have to go the electrolysis route to be darn sure I've got this thing clean and still fliter the heck out of it.


The tank on the Red bike in my Avatar was the worst of the ones I have.It got the electro treatment, oil pump chain on wire swill round and beating.Then sealed with Polyester resin,then with two pack rubber tank sealer(Not available to the public


Then anti-rust treatment and then painted.Dunno why I bothered as I've lost about half a gallon in capacity<grin>.I just can't stand to throw things out.I have a couple more spare tanks and painted tank/side panel set green but don't like it.Doh!




May just do them black again but then I'm tempted to take the engine out and do a Black Satin one again and make the whole bike near Gloss/Satin black on the Blue bike but I do like the blue sooo...
 

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How about just teeing off the fuel line/petcock and running a small clear gas line up to above the tank. Level of fuel in line would be the same as level in tank. Too simple? Not too elegant I admit.
 
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