Fuel flow transducers?

I used to fly a fuel injected single engine plane that had a fuel flow monitor. The sensor was a fuel flow transducer. From what I was told on its operation it was super accurate.

I know airplane parts are expensive but has anybody adapted this technology to cars?

I guess one issue is some fuel is returned to the tank. Where would the sensor need to be?

Looking at this sensor I think the low flow rates would be an issue. 60mpg @ 60 mph is 1gph. http://www.floscan.com/html/blue/aviation.php

What would you do with the info? Doesn't scanguage figure out fuel consumption for you?

Like you posted, because of the return path to the tank, its not clear where you'd attach this to obtain useful data.

We have a fuel flow meter for engineering purposes on semis. It's fairly complex [all digital] and does require a fuel loop to account for the fuel returning to the tank. We can get accurate instantaneous fuel consumption down to about 0.5% with it. But we need that tight if a tolerance when 6.9 or 7.2 mpg makes a big difference on something with a million-mile lifespan. I see a pretty minimal benefit with looking at 40-41 or 57-58mpg..

^^^that makes sense:
fuel from tank - fuel returned to tank = fuel consumed

But would require 2 sensors.

Isn't the whole point of the injection pump that it meters the diesel precisely? Your computer already knows that number.

Diesl said:

Isn't the whole point of the injection pump that it meters the diesel precisely? Your computer already knows that number.

Click to expand...

In the OPs ALH, the computer can guess as to how much fuel is sent from the IP to an injector, but there is direct measurement of pressure anywhere. Injection quantity is assumed based on the position of the collar and theoretical pressure generated. The fuel consumption can be calculated with theoretical pressure generated and the geometry inside the injectors, but doesn't account for wear over time.

It would definitely be more precise to calculate fuel consumption on a CR engine because more is known during the injection event: pressure at the inlet to the injector and how long/how many times the injector is on during a compression stroke. When you couple that with the tight geometry inside the injector, you can much more precisely calculate the fuel consumed. The only major theoretical I can think of would be wear inside the injector.

On the ALH all the computer knows is the duration based on the needle lift sensor. Change any of the variables - say install larger nozzles, switch to an 11mm pump, run a worn out 10mm pump, etc and the math won't add up any more. It is as accurate as the compliance of your equipment to its original factory condition.

vanbcguy said:

On the ALH all the computer knows is the duration based on the needle lift sensor. .

Click to expand...

Nope...

The needle lift sensor is only used to read the actual SOI (Start of Injection) and removes the errors associated with fuel pressure wave variables. The G80 (Needle Lift Sensor) has no other use. In fact, if the crank position sensor fails, the #3 injector becomes your crank position sensor replacement value.

Crank acceleration is the sole means of calculating fuel consumption by comparing its output value to the control collar position in the pump Control arm angle measured in VDC).

When people measure injector balance they aren't reading any value derived from the injectors in any way shape or form.

All they are reading is the SOI value, so as long as all injectors are worn out equally they will all read with little to no variation. If one is severely worn or failing, this will read with a wider range of variation, but only because that cylinders combustion pulse is severely lacking as measured at the crank.

Bottom line, its a big wag albeit a fairly accurate one given the relatively low technology employed at the time.