[shadowzero313]

Floats are cheap, simple, reliable and reasonably accurate. It's also adaptable to different models of gas tanks and cars with out a lot of re-engineering effort. Using flow meters would take at least 3 sensors (new gas, out to engine, unused in from engine), using a weight measurement system would require re-engineering the entire fuel tank mounting system, as well as dealing with the drift over decades of bouncing along the road.

[rayhano]

Thanks, that is really interesting. Plus I heard that fuel volume or density is affected by temperature changes between night and day.