Digital fuel flow meter & fuel tank level project

[Guest masster]

This is an invitation to participate to an interesting project that has the following goals:

1) digital metering and display of fuel tank level (volume)

2) digital metering and display of instantaneous fuel consumption

I believe that an error of less than 3% is quite achievable for both goals.

It is desirable to comment in a constructive way; that is, if you see an issue, do not simply limit to state it, but come with possible solutions to overcome it.

I will start by posting a differential fuel flow meter (DFFM) block diagram.

The same method applies to injection engines, the only difference is the type of bypass valve.

I will post soon a capacitive fuel tank level meter (FTLM) schematic.

Edited 29 July, 2012 by masster

[Guest masster]

Here is the schematic I've promised earlier.

Basically we need a custom-made coaxial capacitor (VC1) immersed in fuel vertically, made of two metallic pipes.

Dimensions are not carved in stone, except for height, which is the height of Felicia's fuel tank, and distance between pipes (1.5mm)

There are two oscillators, a reference frequency one, and a variable frequency one. The variable frequency is due to VC1 that has a variable capacity according to fuel level between plates (our coaxial pipes). Each frequency is then integrated (frequency to voltage) and both resulting voltages feed a differential amplifier. The solution with two oscillators has the advantage of making our capacitive sender temperature-independent. The differential amplifier then amplifies the voltage difference after integrators and we get a voltage output proportionally with fuel level.

How to use this precise voltage, is up to you. My best idea so far is to use a PIC microcontroller that has the advantage of using a dedicated software capable of calibrating a digital gauge that will display fuel volume in liters or gallons.

[Skury]

Why invent something invented...?

http://www.briskoda.net/forums/topic/116341-on-board-computer-felicia/

[Guest masster]

because that thread ended 4 years ago with 0 (zero) success

because none of them are for Felicia (let alone not for carburetor cars)

because they are all using the same low precision, poor reliability resistive fuel sender

because I like things done in a professional, scientific way

because there's more ways to do the same thing

because I like a challenge and I don't like taking things for granted

and a dozen more 'because'.

[Skury]

Masster: I told you, that no problem to buy it in Czech republic and send it to you. :-P

For Favorit with carburator engine Apri made computer "Apri CD1"

http://skoda-virt.cz/cz/inzerce/nahradni-dily-prislusenstvi-prodej-cz/115772-palubni-pocitac-na-fa-apri-cd1/?gotopost=1935863#p1935863

But ok, whe you want to do it yourselves, it's your time. Good luck.

[Guest masster]

thank you for your offer.

but looking at monster SIZE of the box, I wonder if they heard of microcontrollers and SMD.

[Skury]

Fyi... Apri made computer for Felicia with 1.3MPI and 1.6MPI, for 1,3BMM and for 1.9D...

I had computer in my Feli and my Fun and i was very pleased with it. All worked perfectlly.

[Guest masster]

well... good for you.

I opened this topic for those willing to participate in designing a NEW smaller, modern, nicer design, low error digital fuel flow meter & fuel tank level.

I told you also WHY I choose to do so, regardless anyone else is willing to come with better technical solutions.

[Skury]

Ok, i know.

But so you don't say that i can't help you... Try to look to these links.

http://skoda.panda.cz/forum/viewtopic.php?t=1195&highlight=po%E8%EDta%E8

http://feliciaklub.cz/forum/viewtopic.php?f=79&t=20405&hilit=homemade

[Guest masster]

But so you don't say that i can't help you... Try to look to these links.

I would have never said that. I even encourage people to contact you for buying Czech parts for Felicia with your help.

I already looked at those links by searching for "Palubní po?íta? pro Škoda Felicia".

[oldbeaver]

Masster,

 

Nice Project, I offer to help you with it.

 

Unfortunately, I don´t see the figures you posted.

 

Well, I have a Skoda Octavia with built-in computer, however, I also have a diesel Merc without it (W124) and want to develop a similar device as you.

 

Please post again yr pictures or send them to me.

 

Don´t give up on yr Project, despite other's opinión.

 

Greetings,

 

Oldbeaver

 

PD: I have made a lot of research on this, haven´t find an feasible and economic solution, so far. I think many people would benefit from yr Project.

[TeflonTom]

i dont think we will be seeing our old friend masster again

[oldbeaver]

i dont think we will be seeing our old friend masster again

 

 

Why do you say so?

[TeflonTom]

banned user

[adurer]

Here are some useful links:

 

http://code.google.com/p/xarias/

http://jedla.4fan.cz/auto/palubni_pocitac/palubak.php

http://www.jv-technoton.com/

http://www.omega.com/literature/transactions/volume4/t9904-07-diff.html

[RainbowFire]

i dont think we will be seeing our old friend masster again

  :x

[dohnjoe]

i dont think we will be seeing our old friend masster again

 

  :x

I wouldn't bet on that.

old friends can have many names...

[TeflonTom]

I wouldn't bet on that.

old friends can have many names...

 

and ip addresses

[oldbeaver]

Here are some useful links:

 

http://code.google.com/p/xarias/

http://jedla.4fan.cz/auto/palubni_pocitac/palubak.php

http://www.jv-technoton.com/

http://www.omega.com/literature/transactions/volume4/t9904-07-diff.html

 

[oldbeaver]

Here are some useful links:

 

http://code.google.com/p/xarias/

http://jedla.4fan.cz/auto/palubni_pocitac/palubak.php

http://www.jv-technoton.com/

http://www.omega.com/literature/transactions/volume4/t9904-07-diff.html

 

[oldbeaver]

Hello Adurer and all,

As I said before, my Octavia TDI PD has a onboard trip computer, and that gave me the idea of build and program one for my 1989 Mercedes with a diesel engine and a radial pump. Two fuel flow meters, and an Arduino board. But my approach didn´t work.

Very probably, the DFM meters didn't exist (for me al least).

Then I got a MPGuino trip computer, and was trying to get electronic signals from my car for estimating fuel consumption.

Adurer gave me very good links of fuel meters, of professional level, that are the solution to my wish, as can produce a differential signal directly. No need of two fuel meters.

Besides, now I am working in a different car, a 1993 Mercedes with a linear pump. Looking and the videos in Techonoton site and in my car's pump, they use the same kind of banjo fitting present in my IP. So, now it is a matter of study the manuals and get the money for purchasing the differential fuel flow meter and instalation kit. This is first step.

Besides, I have to install my MPGuino in the car, and input to it the VSS signal and the differential DTM meter signal, and I will have a very good estimation of real time fuel consumption and yield.

My Skoda Octavia is giving me about 40 km/l at 70km/h in 6th speed, on a short flat road, cruise engaged, starting measure at 70km/h, not from stand still. This is remarkable good. Isn't it? At 100 km/h it yields 23 km/lt in long trips, as a mean, door to door. Very sensible to sport driving, sprints and such, yield drops substantially. And the driver can see it thanks to the onboard trip computer.

My wife uses the car and she gets about 18km/l where I get 22 just watching my trip computer. Just by use a better driving style.

My 1993 Mercedes is giving me 10 km/l only, while it should yield 12km/l. I am evaluating several mods to it, based on the experience of other drivers. But on some points they have different opinions. I like to test mods in an objective way, and the only adequate way is using a trip computer. So I can evaluate fast and test many things without having to wait for many tanks of fuel.

Best of all with Diff meter, I may not need a programming interface between it and MPGuino, as it may understand the signal. This would be optimal.

Thank you again, Adurer, and I will keep this Fórum updated on my Project progress.

Oldbeaver