mickbrown

With all the high tech improvements in cars, why is it that fuel gauges are not or can’t be made to give a truly linear reading from “F” to “E”? I average about 500 miles per tank on my current car, a ‘19 ES300h: ~ 310 miles from the “top” half and ~ 190 from the “bottom” half. That top/bottom ratio is virtually the same as on every other car I’ve owned since 1970.
Why don’t/can’t they just calibrate the gauge correctly (I.e., non-linearly)?
I know. No big deal. Just curious.

Stroock639

i know what you're saying, especially in my e-class where "1/2" full is really like 1/3 full... my guess would be to reduce the likelihood of accidentally running out and better get one's attention that fuel is getting low

also i'm sure it's minuscule but the gauge also doesn't take into account the little bit of fuel in the filler tube beyond the top of the tank

bitkahuna

iTrader: (20)

seems to me if 1/3 showed as 1/3 instead of 1/2 it would encourage someone to fill up more.

Clicking off to fill up the tube is a mistake as cars need that 'space' for expansion. When it clicks off, you should be done.

mmarshall

Don't know this for a fact, but my strong guess as to why we have non-linear fuel-gauges dates back to before we had the yellow low-fuel-warning lights and the fuel-calculators on the trip odometers. By engineering the needle to drop faster once the tank got below half, it tended to keep the driver more aware of the need to fill up....and not get lulled into a false sense of security.

For those of you who have driven the PA Turnpike, it reminds me of the sign that used to be just outside of Bedford, heading west to Pittsburgh and Ohio...."Next Exit (and Gas)....36 Miles"....which is Somerset, PA. And, I'd assume that some of the gas stations out West are a lot further apart that that.

Stroock639

i'm saying the 1st half of the gauge takes much longer than the 2nd half, that by having the 2nd half go quicker it better gets your attention to fill up sooner than later

you're talking about topping off the tank, that's not what i'm referring to

LeX2K

I suspect it's because the fuel sender is lower than where a good portion of the fuel is. Plus the tank is usually more rounded on the bottom so less volume. You'd think they could easily use a bit of code that compensates for the non linear voltage from the sender vs. fuel level but nope.

4TehNguyen

iTrader: (1)

gas level is measured by a swing arm with a float in the gas tank. When the tank is full, the float is submerged and wont move until level has dropped enough, hence why it stays "full" for a longer time. You only need tank accuracy when you get close to the bottom of the tank, not on top.. Gas tanks are not symmetrical either so its never going to be linear as the level drops

mickbrown

It just seems to me that with all the high tech in cars today, it should be relatively easy to correct this.

timmy0tool

iTrader: (7)

i feel this initially started as a physical causation as mentioned previously but then perhaps evolved to a psychological case.

what i mean is that by filling up and driving down the block, when you see your gauge needle drop linearly might bring unnecessary anxiety and a perception of poor fuel economy. with it staying high and full for longer lessens this effect.

those with electric cars, chime in and tell me when you see your battery drop do you get a little range anxiety? when you see your phone battery life drop a little, do you immediately plug it in? maybe even cell phone manus put in a delay?