mileage computer for a carbureted engine

[dcb]

Hey Yoshi, what do you think about a mass flow sensor in a liquid? too heat conductive?

[dcb]

hmm... well there are thermistor liquid flowmeters for things like blood flow in an artery:
Digital temperature compensation of a thermistor flowmeter

[dcb]

Here is an interesting read for possibly a solid state solution:
http://www.sskteracon.com/ExternalFiles/AN685.pdf

[wyatt]

When I was in college we used a flow meter like this for a lab once.



The fluid pushes up on a ball that is more dense than the fluid you are working with. You can calibrate it to take eye readings (with a glass tube), or use some sort of dual or triple coil system to determine the location of the (usually ferrous) ball by determining magnetic field in the coils. It may sound hard, but I remember it being pretty easy. We were getting fantastic results with water, but it should work for gasoline as long as your materials can withstand the environment.

EDIT:
These are called rotameters or area meters. I haven't found any that will just give a quote that have a reasonable cost, but most are made from stainless and glass. I did find one that was about right, but I guarantee it is way to expensive. It has low flow readings (one model as low as 0.02 gph; my 1.3L idles at ~0.2 gph). They also have ouptuts from 4 to 20 mA, which should make them usable without modification. ROTAMETERS with electric output. DATA SHEET.

[moorecomp]

Hey guys,

How about measuring the differential pressure across a restriction in the fuel line. No flow means equal pressure across the restriction, the higher the flow the greater the differential.

Low Cost Wet/Wet Differential Pressure Sensor

[wagonman76]

Good find. I think it could work well with the mpguino. One would have to change some of the programming. Or just build a circuit to make the sensor run a 555 timer chip to create pulses for the mpguino to read, pulses that are variable based on the input voltage that varies with pressure.

[moorecomp]

Wagonman,

One thing to consider, the fuel pressure would have to be a constant pressure, regardless of the flow. A fuel pressure regulator, if not already installed, looks like it could be had for $20 or so.

[Cepheuz]

i just though of an idea, simple one, but let me know

lets take the fact that my engine is 1289cc (witch would be at WOT)
then the fact that the fuel mix is 13.7:1
that would make the fuel amount @ WOT 94.08cc
and there is only one fuel enrichment and thats the load

so add a volume (the ones in stereos and guitars)dial with a resistor for 6 volt 6volts = 94.08cc
tap into the throttle cable or the throttle to move the volume dial (i'm sorry, i realy don't know the name of it) and ad a contact point the the load enrichment device and do a map for voltage / cc

6volts=94.08cc 3volts=47.04, etc..

add a relay with a resistor and a capasitor to the mix and you can get higher pulse for more acceleration and a pulse for mix increase

could this work?, i might try to do a scematic

[diesel_john]

Originally Posted by Cepheuz

i just though of an idea, simple one, but let me know

lets take the fact that my engine is 1289cc (witch would be at WOT)
then the fact that the fuel mix is 13.7:1
that would make the fuel amount @ WOT 94.08cc
and there is only one fuel enrichment and thats the load

so add a volume (the ones in stereos and guitars)dial with a resistor for 6 volt 6volts = 94.08cc
tap into the throttle cable or the throttle to move the volume dial (i'm sorry, i realy don't know the name of it) and ad a contact point the the load enrichment device and do a map for voltage / cc

6volts=94.08cc 3volts=47.04, etc..

add a relay with a resistor and a capasitor to the mix and you can get higher pulse for more acceleration and a pulse for mix increase

could this work?, i might try to do a scematic

Cepheuz, i don't follow your logic entirely but i think you may have just invented what is called a throttle position sensor or TPS.

[Cepheuz]

ok so this is another, i had a 86' VW Golf GL, it had the k=jetronic fuel system, it had injectors fed by tubes to a control system that meter the ammount of fue depending on the volume of air, in this system there was a fuel pump that whe called cricket bacuse of it sound, its job was to maintain the presure the low presure injectors needed to work, once it reached this presure it shut off automaticalty

so why not natch one of this, connect it between the fuel line and the carburetor and measure the pulses of electricity when it turns on (it turns off automatiacly when it reaches a presure of 3psi i thing or something like that) and its small one just has to figure out the electrical side that sences current flow and sends a pulse, or just put a diode led and it will turn on every time there is flow and conect that led to the light thing i read about in the begining of the thread (the one with the two holes and the ball)