digital fuel meter

i m just want to know that how can i measure the quantity of fuel present in fuel tank.....
& also display in digital form. And quantity should be in Liter............
if any one have an idea about this plz give me suggestion
or mail me at rajat.gkce@gmail.com

You could weigh the tank, subtract the mass empty from the mass of tank with fuel, this will give you the mass of the fuel.
You can then calculate the volume of fuel in litres.

Or,

measure the depth of fuel in the tank (does the tank have a uniform vertical section?) and calcultate the volume from the depth, the area of the tank and the density.

JimB

Would this be a homework assignment?

Another method is placing a pressure port at the base of the tank. Signal condition the analog output of a pressure sensor. Then run the signal to an A/D converter. Scale the display to read out in whatever units you want.

If you search the forums there are likely dozens of circuits and suggestions on the subject,

Ron

Fuel tanks in vehicles are never uniform in horizontal and vertical dimensions.

In cars they are fitted in the vicinity of the rear axle and differential gear and change cross section with every centimeter of heigth.

The fuel gauges built into cars and motor bikes are just "estimators" which becomes obvious when a fully refueled car doesn't seem to consume gasoline the first 100 to 150km and then rapidly decreases in tank indication.

To get an accurate readout about the actual fuel amount in the tank you will have to remove the tank and fill it up liter by liter and measure fuel level height. Thereafter you might calculate for tank content.

Using air pressure inside the tank will lead to misreadings when the fuel level gets low and you are driving hard turns exposing the pressure hose to air before the tank is empty.

Better use the float connected to a variable resistor for that purpose. The software should evaluate "readings" at certain time intervals to make sure the fuel reaches highest and lowest level to compensate for errors when driving curves.

Boncuk

Boncuk

Actually using air pressure won't work at all on a car (assuming this is for a car) as most fuel systems are pretty much sealed with limited venting. You often find they have a slight vacuum or positive pressure when releasing the fuel filling cap.

If the tank already has an lever arm type float fitted then you can use that to work out what is in the tank. You need to make sure you average the readings over a period of time as the fuel sloshes around and the vehicle can have many different inclinations. You would need to calibrate the resistance of the sender vs the fuel available in the tank.

You can also use ultrasonics to measure the distance from the fluid to the sensor.

There was a project somewhere where people were using the capacitance of the fuel to gauge (quite accurately) the remaining fuel - thats up to you to do a search for though .......

Actually the OP never did mention which type of fuel tank? Maybe because it is getting cold where I am I have visions of a fuel oil tank beside a residence?

Pressure would work fine for a vehicle, just don't have it moving around.

Pressure would work for a stationary tank, even if the tank were under pressure or vacuum through the use of a delta pressure gauge.

A capacitive type sensor would also work fine. Capacitive fuel probes have been used for years in aircraft fuel quantity systems.

Anyway, I guess when the OP returns he/she will enlighten us more about his tank.

Ron