not 600 miles?

1/4 tank would be 2.9 gallons?

 

So it has too much?

So it has not enough?

It seems that your two paragraphs contradict each other.

 

Oops! I meant 1/4 gallon!!

 

And some just cheap out on measuring accuracy, going with something sloppy and coarse, then set the reserve high enough so that the units on one end of the measurement error distribution aren't too low. At least, that is my only rational explanation for my car that had the highest "empty" range.

 

A quarter gallon would only get a Tundra 5 miles. Even in a Prius that might leave the fuel pump with inadequate cooling. Toyota likely set these low fuel light limits before they sold the Prius, and tailoring it to individual models is very low priority. they are calling for oil change intervals at the same distance and time regardless of whether the car is an ICE, hybrid, or PHEV.

Can't overlook what the displays would show with an high precision gauge and fuel sloshing around with the car in motion.

 

Geez, I remember my old F150 with the dual tanks, you knew you were getting low when you had to flip that switch. I couldn’t imagine filling up that bad boy with today’s gas prices. Definitely could cover some decent ground though with the dual tanks. I did drive it clear across the country fully loaded up and towing a trailer way back when I moved and flipped that switch plenty of times

 

the trouble with too much reserve is that i never venture into that territory, so if i have too, i get nervous as all get out. it's like ev range anxiety

 

There is considerable filtering applied to the gauge display already. A OBDII-port monitor (e.g. ScanGauge-II) can show the unfiltered sensor reading, and plenty of sloshing is visible, equivalent to multiple bars on my Prius gauge.

While I'd love that degree of precision and accuracy, it would suffer from the slope problem, giving different readings on level vs steep uphill vs downhill vs seriously tilted sideways while parked. A quart might not be enough to keep the intake covered in all those cases. Never mind the sloshing on hard corners.

And even without any tilt or sloshing, a quart won't be enough margin to prevent angry calls to Customer Service when unfavorable fuel consumption conditions causes fuel to deplete earlier that expected. Foul weather, mountain climbing, strong headwinds, and other factors could easily cause a trip segment to burn more than an extra gallon between available fuel stations. Quarter gallon resolution will draw some drivers to start such segments believing they have enough, when they don't. After they get stranded, eventually rescued, and return to cellular service coverage zones, some will likely burn the ears of some unfortunate call center rep. Designing in more safety margin will go a long way to reducing these angry calls.

 

Just occurred to me, how a “quart” got it’s name.

 

Sounded like being on a slight slope, combined with the tank shape and sensor location, is what was causing the fuel tank issues with the Rav4 a few years ago. Then Gerdes managed to get well over a gallon, maybe two, of gas over the official spec of a F150.

Car fuel tanks are shaped to fit into the available space. This does not lend them to being good containers for measuring volumes.

We likely started with imperial or standard systems of measure, because doubling or halving things is mentally easier for humans than working with tenths.