Kinda ScanGauge w/o OBD

[So_SiMpLe_]

Thanks mate but I really wanted to control the engine load so could make my driving as economical as possible!

What if there's a kinda flow meter that connected to the diesel intake and the diesel return would make an intant and average fuel consumption?

Is there any kinda thing that is possible to fit in a car like mine?

[rmay635703]

On an older naturally aspirated diesel your throttle position determines fuel flow rate (newer it depends on throttle position and RPM)

Figure a way of knowing exactly where your throttle is and your halfway there.

And yes there was a fuel meter made for measuring the amount of fuel into the engine but likely you would have to find one in an antique shop, perhaps monitoring your injector pulses with an MPGuino would work well enough?

Good Luck
Ryan

Originally Posted by So_SiMpLe_

Thanks mate but I really wanted to control the engine load so could make my driving as economical as possible!

What if there's a kinda flow meter that connected to the diesel intake and the diesel return would make an intant and average fuel consumption?

Is there any kinda thing that is possible to fit in a car like mine?

[So_SiMpLe_]

Originally Posted by rmay635703

On an older naturally aspirated diesel your throttle position determines fuel flow rate (newer it depends on throttle position and RPM)

Figure a way of knowing exactly where your throttle is and your halfway there.

And yes there was a fuel meter made for measuring the amount of fuel into the engine but likely you would have to find one in an antique shop, perhaps monitoring your injector pulses with an MPGuino would work well enough?

Good Luck
Ryan

That's kinda easy, using a potentiometer on the cable line under the bonnet, but how will it measure the fuel consumption?

My idea with the flow meter is this:

- If you know the amount of fuel that's going to the pump
- If you know the amount of fuel that's returning to the tank

pumpin' fuel - returning fuel= injected fuel

That injected fuel on that precise moment (milisecond, second, hour, minute, whatever) is the one used.

Okay... If you go @ 100km/h and that fuel used is i'd say 5l/h then you have a fuel consumption of 5l/100km

Am I right?


Mate there's a big problem on that, my car is old injection pump, don't have any injection advance, all mechanical, but that wold really work!

What kin of antique shop intrument are you talking about? never seen it, could you help me please?

Thanks a lot mate!

[rmay635703]

Originally Posted by So_SiMpLe_

That's kinda easy, using a potentiometer on the cable line under the bonnet, but how will it measure the fuel consumption?

Thanks a lot mate!

I can't remember the specific names but there were several fuel flow rate meters in the 70's and early 80's that actually measured the amount of fuel going by so you could figure FE. Check around the board and classifieds, someone here likely remembers.

Anyway your motor if stock has a very specific amount of fuel it uses at idle and a very specific amount it uses at WOT, my 6.2's vary by year as toward what those were but as long as the motor is warmed up and not turbo'd fuel consumption at a given throttle position stays fixed except at extremely low and high RPMs.

In other words you would have to look up what they are for your motor and have a way of extrapolating your FE from your current speed and fuel flow rate.

Good Luck, this is really what I would like to see available for Diesel FE since there currently are no good and moderately accurate solutions.

[bestclimb]

Originally Posted by rmay635703

On an older naturally aspirated diesel your throttle position determines fuel flow rate (newer it depends on throttle position and RPM)
Ryan

Not quite, mechanical diesels throttle position will set the volume of fuel delivered when the pump injects it. The frequency that the injector pump does it's thing is tied to RPM. RPM x Throttle position x some number will give you flow rate.

[gone-ot]

Originally Posted by bestclimb

Not quite, mechanical diesels throttle position will set the volume of fuel delivered when the pump injects it. The frequency that the injector pump does it's thing is tied to RPM. RPM x Throttle position x some number will give you flow rate.

...agreed, but I believe the intended thought was simply "...fuel volume is NOT directly a function of air volume..."

[bestclimb]

Originally Posted by Old Tele man

...agreed, but I believe the intended thought was simply "...fuel volume is NOT directly a function of air volume..."

Yep air volume (well rate really) for a NA diesel is a function of RPM and displacement

[So_SiMpLe_]

Right so by the rpm and throtle position is possible to find the fuel consumption!

There's a speed sensor that is easy to fix in my car's gearbox and give speed by voltage!

I have to think about a thing like that and I'll search the classifieds!

The volume of air is not dependant on the throtle position, if you go @ 40km/h in 5th gear and the engine really allmost "dead" if you press full throtle you get full pump injection but the volume of air stays allmost the same!

[mwebb]

from a vacuum gauge to this ...
if you are just looking for a relative value as a vacuum gauge would sorta kinda provide in a gasoline powered engine ...

you can plumb in a MAF sensor ,
any MAF sensor into the air intake , they have a 5 volt reference and a ground and a signal
which you will need to provide a power supply for
some have a temp sensor as well
just monitor the MAF signal

lower = better FE

Originally Posted by So_SiMpLe_

Right so by the rpm and throtle position is possible to find the fuel consumption!

There's a speed sensor that is easy to fix in my car's gearbox and give speed by voltage!

I have to think about a thing like that and I'll search the classifieds!

The volume of air is not dependent on the throttle position, if you go @ 40km/h in 5th gear and the engine really almost "dead" if you press full throttle you get full pump injection but the volume of air stays almost the same!

[rmay635703]

Originally Posted by bestclimb

Not quite, mechanical diesels throttle position will set the volume of fuel delivered when the pump injects it. The frequency that the injector pump does it's thing is tied to RPM. RPM x Throttle position x some number will give you flow rate.

(actually rereading it is true at low throttle levels but not approaching WOT)

That isn't true of my 6.2, the amount of fuel injected is limited by the type of injection pump, more rpms at WOT and the pump can't put in anymore fuel as it hits the limit around 1800rpms. Might be why my motor is only 120hp and newer versions are 165hp both NA. Also explains why I initially get a initial puff of smoke which clears as the motor revs at WOT as the fuel volume can't increase due to the injection pump flow rate limit. (REMEMBER I DON"T HAVE A TURBO)