Cheap Flowmeters to measure inflow into fuel tank

i need to measure the amount of fuel that enters my fuel tank from a petrol pump. therefore I need a cheap flow meter that can fit into the inlet neck of a fuel tank of an automobile, and can measure the amount of fuel introduced. [maybe similar to one used in a fuel dispenser, But I am thinking that would be too big] Cost and size are prime concerns. If an electronic output is generated it will be preferred.

The first problem with this is the word "cheap".

You have a few options the first being to buy **broken link removed**

You could look at various designs of flow turbines to transmit a flow signal then you need to add a display that acts as a totalizer since you aren't concerned with flow rate but a total. Since you are measuring fuel you need something suited for fuel like stainless steel or certain nylon or plastics.

Overall I don't know how you define "cheap" but I don't know of a cheap (I define cheap as under a few hundred USD) way of getting what you want. The least expensive would likely be along the lines of what I linked to. Keep in mind you are looking at fuel which can be volatile stuff.

Ron

It's deja vu now....
See this: **broken link removed**
I'd like you to try out if it works for your application since it measures airflow, but since the defined airflow in this network needs to be a continuum, I'd like to think it would be tantamount to liquid flow as well. The twin transistors are the only ones which will need contact with the fuel flow, isolate the rest. The system costs less than 5 bucks, and that is if you buy a costly op-amp, otherwise it'll be less than a dollar.

About the thermal one I'm not sure if its ok measuring fuel. ignition may be a problem.
About the turbine based one. Seems just fine. Cost bothers me a bit though. I need one for a hundred USD or less.

When it comes to totalizing a rate of flow it can be an expensive proposition. There are a number of variables that need to be considered to get an accurate count. Sorry, but aside from using a paddle wheel or turbine system I don't know of an easy inexpensive way to go about it that would be accurate.

Ron

I see. I'll Look into it. Thank you for your help everyone.