mileage computer for a carbureted engine

[oldbeaver]

Fine, tks a lot. Very ingenious!

I will study it now.

[oldbeaver]

That is interesting. Need to research the function: mpg = f(RPM, Thr, Speed)
Makes a lot of sense to me.

Question: how do you plan to translate it to reasonable results (even relative results serve as for testing modifications), and calibrate it?

Good idea. Nice if you share your progress on this.

Originally Posted by dcb

I do have something that is pretty cheap in mind for the mechanical diesels, but you have to install a throttle position sensor and a rpm or pump rotation sensor and a speed sensor, and I or someone has to teach the guino how to make sense of it.

I'm also thinking about just using a function like speed/(throttle position*rpm) for my bike too, to see if it is reasonably accurate.

[oldbeaver]

Hi James, you know about thermodynamics. Have you ever make such a flow sensor? It may be interesting if you do. Would it be accurate and cheap?

We need two for diesel fuel flow metering. Keep us informed of your experiments on that.

Originally Posted by JamesLaugesen

Hi everyone, my first post here, I've read through this thread with great interest, some real cool experiments happening.

Thought I'd propose some non-mechanical ideas for measuring flow:

A venturi meter.
Along the lines of this:
Venturi Flowmeter
Of course with something clever to observe the pressure differential as a signal.

Inertial meter, or coriolis, whatever you want to call it.
Best description I can find is good 'ol wikipedia:
Mass flow meter - Wikipedia, the free encyclopedia
Need some imagination to use it in a vehicle, especially a bike, but at least the engine could provide a good consistent vibration.

[dcb]

Originally Posted by oldbeaver

Nice if you share your progress on this.

LOL, what progress? I need a rabbit

[oldbeaver]

Wagonman,

Interesting. Can you explain how you need only one flowmeter if you install a pressure regulator?

Besides diminishing error, you cut cost to half, on flow sensors.

I listen. Try to make a diagram if necessary....

Tks.

Another: What is positive displacement pump?

Originally Posted by wagonman76

Another problem with the ball type is it needs to be held steady and vertical. Won't happen in a car. I agree with the positive displacement type.

I am not familiar much with diesels. But with most cars, you could install a separate pressure regulator and abandon the original. Then you could install the flowmeter between the regulator and engine, hence requiring only one flowmeter and halving your margin of error.

[oldbeaver]

Diesel John,

I overlooked this comment. You wrote:

"For a diesels that return to the tank, I would think that a TPS on the fuel regulating shaft, a tach pickup on the injection pump, and dcb's computer would be an easier path, and a less expensive path to follow than what I did."

I have a Throttle position sensor for my Nissan RD28 engine. Have a tach signal of it as well, which I converted to drive my tachometer.
What is DCB´s computer? What about the speed ?

Have any further ideas on this approach?

Thank you for sharing.

Originally Posted by diesel_john

What I have on my diesel rabbit now is an old Zemco mileage computer. The Zemco flow meter has been restored with a 6mm plastic BB and a red LED light source. And because the diesel sends more fuel back to the tank than it uses, i have fuel diagram similar to post 61 bottom diagram. Also see post 84 and 73.

For a diesels that return to the tank, I would think that a TPS on the fuel regulating shaft, a tach pickup on the injection pump, and dcb's computer would be an easier path, and a less expensive path to follow than what I did.

[dcb]

Have a look here for the operation (and possibly follow up discussion as this is diesel related and not carbureted). http://ecomodder.com/forum/showthrea...html#post86551

The control sleeve position is what determines the volume of a stroke. If the control sleeve position can be determined by rpm and throttle position, then cool. Still a little fuzzy on the linkage inside the pump.

The computer is the mpguino I'm sure. OpenGauge / MPGuino FE computer - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com

You might have to roll your sleeves up to get the answers you seek.

[diesel_john]

On my rabbit I use the zemco recirculating ball flow meter just because I already had it and the old Zemco computer. Although one needs to be careful not to get the fuel temperature to high when not circulating back to the tank. A fuel cooler would be applicable, but it also increases the volume of that fuel loop which makes the flow meter less responsive to transient inputs.

[dcb]

Hey John, you may have mentioned this already, but it might be simpler to figure out/calibrate diesel consumption if you measure the return line flow, and subtract that from what the flow "should" be in the main line if the control sleeve were at max travel for that rpm. idle consumption detection might not be an issue anymore and fluerburger might actually be a good fit (what is min return flow rate?).

[diesel_john]

We touched on that idea before but not from that angle, the return fuel is substantial. Your thinking perhaps that the return fuel is the inverse of comsumption. hmm... lets look in that pump again. l like your diagram in post 137 better. better view of vane pump pressure regulator