MPG on Trip Screens

The crystal ball wasn't an option - it's impossible otherwise forward projections.

 

Yes, but it is predicting miles until empty, and it would be helpful to give the MPG estimate it is using to arrive at that number.

 

I can't see how it can know how or where you're going to drive for the remaining kms in the DTE?

It doesn't know if you're going to have 3trips to the Gold Coast in "normal" traffic where you'll average 3.5l/100km, or 20 short trips to the local shops, library etc where it barely warms up and averages 4.9l/100k.

Only the driver knows that.

 

But the same logic applies to the miles to empty prediction.
Based on the miles to empty and the remaining fuel in the tank it could easily calculate and display estimated or expected mpg.
E.g. if it knows you have 5 gallons left and 250 miles to empty it could display 50mpg.
Although, as the miles to empty calculation is based on the mpg you were doing at the last fill up, showing expected mpg is not a useful display as it is actually not a prediction but just a summary of your previous mpg.

 

Yes, "250 miles to empty" is very rubbery. I think it does calculate it more often than from the last fill - but couldn't be certain. My last 2 FORDs did.

My previous car could show 600kms to empty and actually climb higher as I was on a gentle highway drive - I had about the same DTE after 50km as I'd started with - though obviously after 300km it had dropped correctly.

 

I suspect that the engineers just figured that it was easy to show the average mpg you got (past tense) for each of the trips. But not logical to show what you got for the future because you haven't got it yet. They were probably in a mindset that that mpg number is just history. If they thought about it, I'm sure they could have programmed it to show the future mpg predicted, but it would probably be the same as the mpg it's already displaying for the distance traveled since the last time to started the car or something like that.

Most times in my case, DTE is bogus anyway.

 

The displayed mpg too, about 7.5% optimistic, on our 3rd Gen.

I wouldn't pay him any mind.

-Bob Dylan

 

There are quite a few bogus things on the Prius, distance to empty and displayed mpg figures are just a couple.
Here in the UK speedometers are allowed to read 10% over but not under the actual speed, so what do Toyota do, set them to read 10% over, when they could easily have them reading spot on, or at least a lot nearer.
I suspect the Hybrid battery SOC meter is not accurate as well.
The fuel gauge could be more accurate, although it does err on the side of caution, showing empty (and zero miles to) when there's still a good 7 or 8 litres left.
The road sign recognition is useless.
The lane keep assist is too slow to respond, it only warns you after it has actually crossed the lane markings, a bit late if there's a semi coming the other way.

 

I find if my speedo is reading 80 kmh, my Garmin (satellite navigator) will show speed 78~79. So maybe 2~3 percent? I'm ok with that. The reasons for speedometers reading high are fairly commendable, in my opinion.

 

My speedo is out 3km/hr at most speeds - ie driving at 60km/hr = 63; 80=83, 100=103. According to both my old and new Sat Navs and my phone.

 

The other thing I do - so DTE doesn't need a l/100km. I zoro TRIP A when I fill - so I can flick between DTE and TRIP A - gives me a good story.

 

I also zero trip A, when I fill up, so I can check my tank to tank mpg and enter it into Fuelly. I've never zeroed trip B so I have a lifetime mpg still on that. I usually drive around with the current journey mpg display showing and look at the miles to empty display when I get down to the last pip on the fuel gauge (just as a matter of interest as it's usually way out anyway).

 

But 10% over, gives the impression that Prius drivers are slow, when you're going 70 mph according the speedo, you're only doing 63.
I have a GPS dash cam that shows the true speed and usually go with that, setting the cruise to 77mph in a 70 limit.

 

Aren't the miles to empty prediction always using EPA rated mileage for calculation for both Gen4 and PRIME? If it is using past historical mpg to make future prediction, the mile to empty prediction would vary every time you fill up depending on how you scored on mpg during last fill few drives, but that is not the case. I get the same miles to empty every time I fill-up. That said, it is not miles to empty, but rather miles to when empty warning light comes on. It usually leaves ~2 gal of spare gas left in the tank when MTE hit zero.

 

I've only filled mine once and that was two days after I got it. Lots of test drives, I'm sure. It showed 360 something miles left with a totally full tank. Not even close to EPA.

 

No, Not EPR rated range of 640miles (which is sum of 25 miles EV and 54 mpg x full tank 11.3 gal), but using EPE rated gas milage 54 mpg for amount gas in the tank till the empty lights comes on. The warning light comes on ~2 gal before completely empty, thus only 9.3 gal is used for calculation of the miles to empty. At a fresh full tank fill-up it should be ~500 miles.

 

I don't think so - I think it's based either on your last trip or last fill. Most of my driving is reasonably consistent, but when I do something different for a week or so (some long runs), it gives a different DTE.

 

Hummm, admittedly I havn't paid much attention to DTE number on my car in the past. I don't even have any photo record of it, and I keep most of, if not all, eco log and other data displaced on MID. I will have to work on that. Thanks.

 

My miles to empty is different every time I fill up. High in Summer and low in Winter.