Consumption graph incorrect

[volcomholls]

I'm not sure if this is a problem, but something that has happened a few times in the past few months at random. In the first 5 minutes of driving, I'm usually always around 25mpg for the first graph bar the mfd shows. But tonight the first bar that appeared was full (at 100mpg) for the 1st 5 min and had one full car at the bottom of it for regen. There is no way possible that my 5 min trip was completely gas-free. Has anyone else noticed this? Is it possible there is an underlying problem... ??

I hope not! The prius just turned one year old last week!

[Rokeby]

volcomholls,

Getting that first fat yellow bar to be full sounds like a blessing, but maybe
not. It is unlikely that it signals a problem. The full bar doesn't mean that no
fuel was used, just very little relative to the distance travelled in that 5 min.
period. I suspect that essentially your car was operating like an EV, and
drawing energy nearly exclusively from the HV battery.

It would require that most if not all of these conditions for it to happen.
* the engine/catalytic converter remained well heated from previous trip.
* the time stopped since the previous trip was relatively short
* air temps were 60+ deg
* you were using little or no cabin heat or cooling
* at the end of the previous trip, 6 blue or even 7 or 8 green bars were
showing on the consumption screen
* for the first 5 minutes the road was level or slightly down hill
* for the first 5 minutes speeds didn't exceed 30 MPH
* all accelerations were gentle

(The horizontal axis of the consumption graph is time based. You could travel
only a few yards or even feet in 5 min. and see the first bar full. Any apparent
benefit or reason to rejoice would be completely erased by just one 5 min.
period traveling at typical road speeds. In this special case, that 100+ MPG
spike is meaningless.)

Getting that first fat yellow bar to be full while running as an EV can be
misleading, and even inefficient. If you run the HV battery well down past 6
blue bars, the computer will then run the engine more to get the bars back
up to 6. There's no way to stop it, and you wouldn't want to.

So, the only way to know if that full fat bar is good or not is to note the
ones that followed. Was the second and maybe even the third somewhat
low? That would be the pay back as the HV battery is recharged.

The folks who consistently get FE/MPGs at 50+ say that it is best to use EV
mode driving only in special cases like to extend a glide over a hill and then
go into regen to recoup; or short, low speed segments in a parking lot.

Hope this helps.

[diamondlarry]

What Rokeby said. I had one yesterday like that and it was because I was in my mom's for only a few minutes and was able to EV for the first .1 miles out of her mobile home park and only had to pulse up to 30mph then was able to coast/glide(no arrows) for just over .5 miles or so.

[volcomholls]

Thanks for the lengthy explaination, but almost none of those conditions were present. I drove about 2.5 miles up to the grocery store, parked for about 30 minutes then drove back home 2.5 miles. It 100mpg bar showed up on the way home, which was only 5 minutes so I didn't see any subsequent bars. It was about 48°F outside, at nighttime. The trip is a mostly mild up & down hills. I know the battery on the other screen was not green, but I don't know how many blue bars. I understand that it depends on the time and miles you go, but I know didn't power up and sit there for 4 mins then drive on EV through the lot. The few other times I've seen this have been sporatic, but I remember that it was mostly the same (in the morning on the way out, no waiting, no hot temps).

I have a feeling if I take this to the dealer, the will never be able to reproduce it, and of course, probably not even comprehend what I'm trying to explain. It may be nice to look at a full 100mpg bar, but I know something is not right in the Prius' calculations.

[Rokeby]

Originally Posted by volcomholls

Thanks for the lengthy explaination, but almost none of those conditions were
present...

That being the case, I haven't a clue.

If as you say ICE/catalytic converter were cold on both 2.5 mile legs
of the out and back trip, 25 MPG would be typical in my experience.
The energy to make those two trips could come from only two sources:
the gas tank or the HV battery. Barring Divine intervention --Did you
hear any unworldly music on these trips? -- that energy should mostly
come from the gas tank, after a short initial spurt from the HV battery.

But at 100+ MPG it would appear that the energy came mostly from the
HV battery. Most Unexpected. I don't get it.

[volcomholls]

Well I hadn't seen this in a while, but its back to doing it, twice in 2 days this week. Anyone else see this strange phenomenon yet??