Difference between actual and reported panel consumption

I'm not talking about distance to empty, obviously the car doesn't know how you will drive in the future I'm talking about the MPG or l/100 km display in the car and hand calculated on the pump. As I said in Gen3 it was off by 6%-8%, looking at some data from Gen4 I would say the BC is not more 4% off.

 

Sorry, what is BC?

The DTE and MPG are related and compiled by the computer from the same data set - I've checked it a few times and have seen between 5% and 9% variances. On a long trip with few stops and relatively steady driving, the variance was smaller - normal short trips had a bigger variance - which is understandable as it's got more data to compile.

I never bother checking it against reality - just use it as a guide - the real pump price/distance calculation is the valid one.

 

BC - on board computer.

DTE and MPG display are not related at all. DTE is more accurate if you do the same driving scenario every tank, MPG display in my experience is off by roughly the same percentage every time, no matter the driving style.

 

No - DTE and MPG use the same data to compute them.

I was reading on BMW and Mercedes FORUMS and they're saying the same - though it seemed that Merc was even more inaccurate.

The bottom line is - they're just a guide. To get it 100% accurate, you'd be paying a lot more for the car.

 

DTE uses past MPG data to predict the future
MPG is only past data and obviously can be more accurate

 

it does not take into account the safety margin

 

Interesting: Wayne Gerdes (CleanMPG website founder) had a pre-production 4th gen for testing, and he found the dash displayed mpg closely matched his calculations. It would seem they hadn't introduced the exaggeration factor yet.

Just conflation Alan. The only thing preventing accurate dash displayed mpg is Toyota management.

 

And BMW, FORD, SUBARU, MERCEDES, VW, AUDI, JAGUAR - all of them have similar discussions on their forums.

 

A couple of points:

1. Our Honda Civic Hybrid was the first vehicle we had with mpg display. It was very consistant, either spot-on, or 0.1 pessimistic, in the liters per 100 km method.

2. A ScanGauge hooked up to our Prius showed fuel economy that matched calculated. The car knows internally what the number is, but someone at Toyota wants the display to exaggerate.

 

I am late to this discussion, but with my 2018 Prius over 17000 km, I find that on average the car reports 6.9% better fuel economy than it actually gets from measured fuel as reported by the pump. It ranges from 5.4 to 9.1%.

Your fuel economy does not seem that good (but maybe you are heavy footed!). My average (actual) is 4.7 l/100km over the whole period (and that includes a cold Canadian winter). See my other post is this forum dated September 3rd.

Dave

 

Here in Ontario, pretty much all the gas is E10 (10% ethanol) and likely the Transport Canada (our EPA) are for just gas, so we shouldn't expect to agree there. Also, our gas pumps are "corrected" to 15C but the metering inside the Prius likely isn't, so that could cause some discrepancy.
Also, I wonder how much the gas pumps can be off without them getting charged? I wouldn't put it past the gas companies to be pushing the limits as far as they can, especially with respect to their "correction" thermometers.

 

At >30k miles on my 2018 Prius, my calculated (real) overall MPG is 54.73 and the reported MPG is 57.40. Of course, it varies with each fill.

 

Yep, really bummed out about this as it is my only Prius that is a steady 4.2ish MPG off from the display. All of my previous ones were less than 2 MPG and usually spot on.

My first Honda Civic Hybrid (2003) was that bad but the build quality was excellent. Unfortunately they we down hill after their first one and I am not going back.

 

I'd say that's right on the money. 5% above actual calculation is about right- and at 50K my 2017 is right there with you.

moto z3 ?

 

I know this is a very old thread so I hope it's OK to go back to it...
I'm trying to set this spreadsheet up for myself but continually get an error using the formulas that you have shown. Can you tell me what I am doing wrong here please?!
Thank you.

 

This is mine -

I haven't played with spreadsheets since I retired 12 years ago (that one originates from about 20 yrs ago) - but check that the "0" is a ZERO, not an "ohh" as in letter.

 

Thanks for the reply Alan, much appreciated. I definitely used the Zero but out of sheer frustration even tried the letter O just in case! Neither work. So annoying as this is exactly what I am looking for so I can start tracking - first time owning a Prius and going on a long drive today so really wanted to see how the consumption is.
I guess it's pen and paper until I figure it out!