Best sensors for measuring fuel flow rate in vehicles

I like your negativity & not thinking from the resolution perspective. Some time it bois down to personality!

I answered you a while ago in your other thread (it's a bit confusing when you have two on the same topic.)

You probably won't like my answer any better:

A flow sensor capable of giving accurate measurements of the amounf of fuel pumped into a motor vehicle during re-fueling would have to be the same bore as the existing fuel filler and be installed properly in line with it. This would have to meet stringent regulatory requirements for safetey (especially in petrol powered vehicles). seperate approval would be needed for every vehicle type.

I don't know of an off the shelf flow sensor that would work as the core of the design.

I can't see the cost being less than a few hundred pounds/dollars per vehicle even if the product were made in reasonable numbers.

What it boils down to is that your problem (checking amount of fuel delivered into a vehicle) can't reasonably be addressed with a flow sensor of any known type.

This means that you will need to step back and look at other solutions to the problem, or invent a completely new kind of flow sensor.

MK

You can measure the depth of fuel in the tank using a pressure sensor at the bottom of the tank. It will require calibration table to translate depth to volume.

You could also measure depth using other methods such as ultrasonics or capacitance.

I hope it wasn't my comment that sparked the snowball of negative comments, I just wanted a little clarification of the problem. It is a solvable problem, including a low cost target.

michaelkellett  Thanks, your inputs are valuable. Agree & we are trying to figure out the complexity & cost-efficiency towards the resolution which is why reached out to this learned community for the inputs   

dougw  Thanks, i researched & discussed on load-cells but they are inaccurate & has limitations. Neither ultrasonics or capacitance sensors fits the resolution well. 

The ultrasonic solution from TI that I tested could measure 20 micrometer liquid level changes with an affordable MSP430, 2 dedicated ICs and a piezo transducer.

There are a lot of challenges to install any sensor in a fuel tank, but resolution isn't the biggest one.

The TI capacitance measurement chip I tested could measure capacitance changes down to 0.3 femtofarads and it had 28 bit resolution. If the tank was 1 meter deep, that would be a resolution of 0.0037 micrometers.

/products/roadtest/rv/roadtest_reviews/557/texas_instruments_fd

I'm guessing that the idea is that you would take something like this:

https://www.amazon.in/MagiDeal-Gasoline-Delivery-Dispenser-Electronic/dp/B07JRFSPVD/ref=sr_1_10

which already has that flow meter built into a trigger nozzle, then somehow stick the pump delivery nozzle snuggly into the back of that in such a way it forms a perfect seal and pumps the fuel at a steady rate through the meter and then into a normal petrol tank receptacle.

However, there normally is a venturi tube in the pump delivery nozzle, which would have to be routed separately to the end of the nozzle with the flow meter in order for the delivery nozzle to open its dispensing valve. The position and size of this venturi tube probably varies widely from nozzle to nozzle.

You then have to scale that down in such a way that the scammer doesn't notice it attached to the car and request that you remove it before they will deliver fuel and scam you.

In theory you could insert the flow meter into the filler pipe out of view with a remote display but that would then require modifying a wide range of vehicle types and probably void any warranty / insurance in the process.