In most cars I drove, I observed following trend with fuel gauge.
When full tank, the needle moves very slowly from F mark.
Once near half-way mark, it moves much faster.
At a quarter tank full level, it movest to E at a very fast pace!
So, the movement is not linear all the way from F to E.
Nowadays if distance to empty value can be shown, why not the "Litre remaining in tank" not be shown??
PS: Some cars do have a digital fuel gauge now but instead of actual value, it shows digital bars (like mobile phone battery level).
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"So, the movement is not linear all the way from F to E."
It's more important to know you have no fuel than a tank full so it doesn't need to be linear.
It only moves slowly from the F mark as you have about 2 gallons of fuel to use before the float in the tank begins to move - I can do over 100 miles in most cars I've owned before the fuel gauge starts moving. From then it's probably close to linear.
With hire cars this can work in your favour - never fill to the brim.
If the car is delivered with the needle on F it probably isn't actually full, but they expect it back full. If the car has a computer use this to calculate how much fuel you have used (distance/average fuel consumption) and refill with this amount, rather than brimming it.
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It's sensible for the fuel gauge to work the way they work, fuel tanks are rarely a uniform shape usually holding much less fuel in the bottom third (depth wise) of the tank than the top two thirds. This is why the gauge suddenly dives when you get into the last third (depth wise) of the tank's capacity, coz you will use up the fuel in that smaller "third" much faster.
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The Rio must have an odd shaped tank then.
I can drive 80 - 130 miles (depending upon driving style) before the needle starts to move.
Then it will decline quite quickly until reaching a quarter of a tank.
From then on its a slow gradual decline to the first 'feed me now' marker.
The tank size is reported as 42 litres yet when I fill up it seems nearer 45 litres to fill.
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Interesting mine does this,now i know why.
thanks
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It's sensible for the fuel gauge to work the way they work fuel tanks are rarely a uniform shape usually holding much less fuel in the bottom third (depth wise) of the tank than the top two thirds.
True enough, it just seems odd that on my Vectra B GM went to the trouble of fitting a level sensor with a relatively complex thick film circuit on it to give a non linear response to float position, yet the fuel indicator still gives a typically non linear response.!
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The instrument panel in my friend's 1998 Elise S1 had a litres readout like you mention. It was just as erratic / non-linear as a traditional analogue gauge, as it relied on the same float & resistor sender setup as a normal gauge.
In theory the engine management system could be used to calculate fuel use, much as it is for a fuel computer, but it would still need some means of knowing how much fuel had been added to the tank to begin with to calculate remaining litres with any accuracy.
Apart from any of this, the distance to empty and fuel consumption indicators on modern trip computers are notoriously inaccurate (optimistic), so would probably be worse than current fuel gauge setups.
Edited by DP on 28/01/2010 at 14:34
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Since I've had my current Focus, I've found that I don't particularly look at the fuel gauge as much as I used to. I look at the computer read-out for the "XX miles remaining" figure to judge how long I go before re-fuelling.
I'm now probably working a bit more close-to-the-edge operating that way, because I'm running it lower than I would've done by just looking at a swinging needle which wasn't as specific.
Once the novelty's worn off, maybe I'll go back to the fuel gauge
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Why the DTE was introduced? If you have a fuel gauge, why do you need to know DTE?
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Assuming 'DTE' means trip computer? then I'd say it's because the proportion of drivers who can work out their average fuel consumption over the last 20 (say) miles and then predict their remaining range from the fuel level indication is very low.
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>> PS: Some cars do have a digital fuel gauge now but instead of actual valueit shows digital bars (like mobile phone battery level).
My 1989 Volvo 480 had one of these, with digital bars. If there was strong sunshine, the gauge was unreadable. As I realised when I ran out of fuel once on the M25 near Reigate. I Hadn't checked the gauge when I set off from Reading, and when the bars went red they didn't catch my attention as I couldn't see them. One for the lessons learned log.
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I suppose it boils down to the fact that you don't need to know exactly how much fuel you have left - an inkling is enough really - these days I tend to rely on the "range" mileage than the gauge (which is an LCD bar thing in the Honda)
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Roomsters got one too, it seems to go down smoothly as well...
In theory the engine management system could be used to calculate fuel use
I thought that they did already, if I put some fuel in the tank, but don't fill it, the computer recalculates the "miles before fillup" reading, and that figure also seems to be based on the cars current average mpg since start of journey...
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On my Mazda6, when the fuel light comes on and even when range says 0 miles left... I can only get about 54 litres or thereabouts in the 64 litre fuel tank. Now would I risk running it too far like that with apparently 10 litres remaining.... no.
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>> PS: Some cars do have a digital fuel gauge now but instead of actual value >> it shows digital bars (like mobile phone battery level). >>
>>My 1989 Volvo 480 had one of these, with digital bars
My 1983 MG Maestro - any advances? :-)
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Fuel gauges, pah!
When it starts spluttering, you reach under the tank, switch to reserve and start looking for a petrol station.
Remember to turn the tap back to 'main'. ;>(
Edited by bathtub tom {p} on 28/01/2010 at 16:35
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On cars with duel fuel how does the lpg works is there a seperate gauge or just a low gas warning light? or does it automatically switch to petrol?
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On an aftermarket LPG system there is usually some kind of low-rent digital gauge stuck to the centre console, along with an LPG on/off button that looks like something from a 70s Toyota...
I believe on some factory fitted LPG systems the standard fuel gauge reflects the fuel in use (i.e. shows petrol level on petrol and then when switched to LPG, shows LPG level instead), which can be confusing...
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I can't remember the last bike I had which had a fuel tap and reserve!
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>>PS: Some cars do have a digital fuel gauge now but instead of actual value, it shows digital bars (like mobile phone battery level).
We had a hire car (Fiesta) in Cyprus a couple of years ago with this type of fuel gauge and I had a rather stressful descent of the Troodos Mountains (where I couldn't find a petrol station) through a remote area thinking I was running on fumes. Eventually found one near the coast and filled up and it would seem that there was still at least a couple of gallons in the tank!
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I can't remember the last bike I had which had a fuel tap and reserve!
That's supposed to be progress; however the old system might have been fiddly but it was at least foolproof, unless you'd forgotten to switch back to main tank after refuelling.
The only things that ever went wrong with the old fuel taps on bikes was that they either leaked or got blocked; renew seals or replace tap for former, clean out for latter.
Problems with vacuuum or electrically-operated taps seem rife though if you look through discussion forums.
Early in my lorry driving career I learned the hard way that you should never trust a fuel gauge. Took a lorry out, having checked the gauge, ran out 50 miles up the road, was then told by another driver that the gauge had been like that for years. These days if I have to use an unfamiliar lorry I always take the fuel cap off and have a look, or if it's got an anti-syphon device fitted, rap the tank with (gloved) knuckles just to make sure.
Edited by Harleyman on 28/01/2010 at 20:58
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Or you could do what a girl I know did with her bike, she took her girlfriend to the middle of nowhere then just before the return journey she decided to check how much fuel she's got - with her cigarette lighter as a source of light - luckily she only singed a bit of hair - although standing miles from anywhere watching her bike burn probably taught her a lesson - thank goodness she wasn't sitting on it when it went up.
Edited by Dynamic Dave on 30/01/2010 at 01:09
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