Any interest in developing an open source fuel economy gauge/computer?

[dcb]

One of the things I was wondering is if you could make a small mass airflow sensor that you put in the fuel line instead of the airflow.

Note: you might want to skip the self-cleaning step that GM uses where the thing gets red hot at startup

[dcb]

Originally Posted by MetroMPG

Permission Denied: Access to this page is restricted (either to project members or to project administrators) and you do not meet the requirements to access this page. Please contact the administrator of this project for further assistance.

Sorry, I put it in the development forum without realizing it was private. Anyone need development forum access? You will to check in code. Though the public can get to the code they cannot modify it.

Yes please, instrumentation forum (under DIY or standalone?) . Lets move this thread there and cross link it with the opensource forum.

Metro, can I make you a sourceforge admin since this open source mpg gauge thing was your idea?

[RH77]

Originally Posted by dcb

Sorry, I put it in the development forum without realizing it was private. Anyone need development forum access? You will to check in code. Though the public can get to the code they cannot modify it.

Yes please, instrumentation forum (under DIY or standalone?) . Lets move this thread there and cross link it with the opensource forum.

Well, the thread was moved to "DIY" with a re-direct -- not sure what you mean about the cross-link (?)

RH77

[dcb]

re: crosslink, There have been links here to the sourceforge project, so I added a link in the open discussion forum back to the original discussion here.

https://sourceforge.net/forum/?group_id=222201

Also I updated the development forum so it was public, anyone can see my lame project plan now
https://sourceforge.net/forum/messag...msg_id=4859237

[diesel_john]

Originally Posted by Duffman

I definately think that the MAF approach is the easierst way to go and would work fine if the engine didnt deviate away from stoichiometric A/F ratio but I think that is a bad assumption. I think a carb is much more likely to have A/F ratio fluctuations than FI.

totally agree,
but more convincing than a vacuum gage, when i see pounds of fuel disappearing per unit time or distance.

[diesel_john]

Originally Posted by dcb

One of the things I was wondering is if you could make a small mass airflow sensor that you put in the fuel line instead of the airflow.

Note: you might want to skip the self-cleaning step that GM uses where the thing gets red hot at startup

definitely hold the burn off :-)

i imagine a new MAF is pricey. i was just interested in the concept because in the yards they are recycling them by the bucket fulls.
A turbine, or paddle wheel is less expensive for measuring liquids. measuring low fluid flow is still at least a $100.

what do you think of dividing pounds of air by 100 to get an approximation for gals. of gas. 14.7 x 6.25=91.8
then run a half tank thur. to tweak the cal. to individual driver and car.

[dcb]

Originally Posted by diesel_john

then run a half tank thur. to tweak the cal. to individual driver and car.

That's the rub there, hopefully the individual will be a variable as (s)he gets better technique. A fair number of details to sort out also, but we should keep it on the table and if anyone runs with it then cool! Also it could be deduced with the MAP/RPM/Air intake temp sensors and a guess at the VE and displacement of the engine, though might be even more to figure out down that path

Having gotten a closer look at all these cheap and tiny computers, I'm starting to think the "fill a little cup, let it empty into the carburetors, and fill it again, and count how many times you've filled it" approach is really viable, accurate at low flows (just not instantaneous), and possibly cheap, especially if you repurpose (drill out) an injector from the boneyard or other common fuel valve/solenoid.

[dcb]

FYI, I can't use the free version of codevision for a serial communications listening device, I'll have to live with arduino-0010, which has completely different header files of course, so it can't compile your nitrous example without modification. I've added a few entries to CVS, trying to figure out how to release something to the download area for that java laptop thing.

[s2man]

Originally Posted by metroschultz

for a 1996 Cav. 2.2...

Thanks much, Schultz. That cruise signal sounds nicer than the a/c VSS. I wonder if it is on as many cars as the VSS... Do you know if the VSS is a/c on all cars?

<brainstorming> Why a/c? Why wouldn't they just use a sensor on a cog, like the ABS system? Could we tap into the ABS signal? What percentage of cars have ABS vs. cruise signal vs. VSS? The most common signal may be the one to use for highest compatibility </brainstorming>

@Coyote X. From what I've read about Zener diodes, one of their features is they can handle high negative voltages which would burn out a regular diode. So it seems a Zener should still give us a good, countable signal from a/c VSS signals, and also from dc pulse signals. Is this correct?

[MetroMPG]

dcb, I've registered @ SourceForge.

Are we going to take the discussion there? I assume SF has better tools/features for pursuing this type of thing than just continuing this thread, yes?

If so, who else is going to register to participate?

If so, I'll start a new thread to keep people @ EM updated on what's going on.