My real-world experience with the PHV

From my calculations, you had 56.7 mpg while in hybrid mode. Given the length of the drive and the attempt for "real world" driving, I'd say that's pretty good! It seems that the extra weight from the batteries aren't affecting things too badly.

 

I was thinking just the opposite -- 57 mpg at 47 mph is quite a bit less that a standard Prius would get, unless Tony had a fair amount of braking along the way.

 

Average speed doesn't work that way.

Mine is always in the low to mid 30's, despite my daily commute including a drive at 70 MPH. Anytime the vehicle is on, moving or not, the clock is ticking... which brings that value down deceptively lower.

In other words, 57 mpg is way higher than I ever see... even at a displayed average of 34 mph.
.

 

Despite what everyone has posted here and elsewhere, I am not certain
about the PHV's algorithms for use of the two new drive batteries. I think
that depletion of the two drive batteries comes first, but I could be wrong...
again... or still.

From what I've read here when I'm running errands in my Gen II, I go
to the farthest away place first and directly, and then pick up the closer
places on the return.

In the case of the farthest place being ~16 miles away, I take it that
with the PHV, it would be more efficient to pick up the closer places
running on the two drive batteries and come home in normal hybrid
mode.

Am I even close here?

 

I can only imagine a difference in FE in Rokeby's scenario if the ICE does not warm up completely before it is shut off, or the stops are long enough to let the ICE cool off enough to have to go through the warm-up sequence again.

 

I think I'm getting a little clarity on how the PHV works.

So I'm going to float a trial balloon to check my understanding:

* On start-up the PHV defaults to all electric drive using the two HV sub-packs
up to some predetermined speed -- 65 MPH?.
* While there is still useable charge in the sub-packs they, or perhaps only one of
them, will accept regen from braking or blue-arrow, no go-pedal decelerating.

Now I have to make some guesses:

* If you stomp on the go-pedal for hard acceleration before the sub-packs are
depleted, the HSD will activate the ICE.
* The ICE stays on until the ICE and catalytic converter get warmed up, S4.
* During the ICE/CC warmup stages, any regen from MG1 would go to the two sub-packs.
* During the warmup stages electrical power to supplement the ICE comes from the
two sub-packs.
* After ICE and CC are warmed up and the ICE stops on its own, electric drive on
the two sub-packs is again the default until the sub-packs are depleted..

Back to what I think I know:

* Once the two sub-packs (or only one of them?) is depleted, the car reverts to
standard hybrid mode with regen going only to the HV battery.
* Once depleted, the two HV sub-packs can only be fully recharged while the car
is shut down via the external charging system.

Does this sound about right?

 

It's a shame you didn't get a chance to try the course in the reverse direction as well. It would be interesting to see how you would do by comparison. Is there still time to do it today?

 

I would like to know whether the difference in MSRP of the PHV and the PZEV versions of compatible Prii would come into the equation of the mpg advantage.

This is of course if the planned MSRP of the PHV is more than the PZEV.

How long will it take to recover the added cash outlay before you start saving.
You may have to pay more to pollute less. I guess this could be said of any PHV like the VOLT.

 

That's a bummer. I'd love to see the plug-in batteries be able to take advantage of long downhills. That would be a big bonus. Going up hill you are still going to get the same mileage as you do now (sans the extra battery weight). Being able to go 15 miles on EV and then recharge for another 15 miles would be really great - especially because we have a lot of long hills around here.

 

I believe these are just test cars for lithium battery testing and Toyota will configure the production cars to a better setup. So don't thing what these cars are doing now is what they will be doing when they are sold to the public.

 

But at the same time, we know Toyota is monitoring Tony's posts here and our discussion of them... open discussion about the pro's and con's of their design choices in this prototype, as well as what we would like to see done in the production model, is still valuable feedback for them. So I say complain away - it's the best way we have to influence the final product.

 

Tony - What sort of mileages were others seeing on the route? I'm just wondering how the Prius compared overall, although we can easily admit that driving style alone can cause big differences, so any differences wouldn't be attributed entirely to the car, but also to the crazy things some people do.

It would have been awesome if you could have run the course 3 times - once like you did with a fully charged battery, once with a fully depleted battery, and once in a 2010. Hopefully, having the same driver on each trial would mean the style and speed would be roughly the same, and would have given us some great comparisons.

 

There were no 2010 Priuses in the competition. The Gen-2 mileages ranged from 62 to 92 mpg. It looks like Tony's Hybrid mileage was 77.4 for the course.

 

That's kind of low.............

 

This study from Carnegie Mellon shows a model that suggests some of the data Tony has reported:

http://www.cmu.edu/me/ddl/publicati...aras-Hauffe-Michalek-PHEV-Weight-Charging.pdf

One thing from this study that seems to ring true was how quickly the PHEV advantages disappeared once the battery range is reached. Now the study authors were not changing the driving style to maximize return on PHEV investment. PHEV driving style to optimize performance remains an area not yet studied in depth. To some extent, it is a chicken and egg 'which came first' problem ... and a nice problem to solve.

Bob Wilson

 

This really grabbed my attention:

http://priuschat.com/forums/prius-h...al-world-experience-phv-blog.html#post1152111

I don't think I could get anywhere near 70 MPG in the first 5 miles no matter what I try with my 2009. This is just amazing.

 

Tony, I'm really enjoying your blog. Keep up the good work!

This is almost exactly the way we drive our 2009s. We're retired so 90%+ of our driving consists of short hops - to a store, club, another golf course, movie theater, restaurant or a friend's house. A plug-in would mean almost never buying gasoline and doing most of our driving for $0.022 per mile for electricity. We ocassionally go to a baseball game or other event 20 - 30 miles away, but that is only once every week or two.

At first, this sounded like the perfect vehicle for people like us. I was ready to tell my wife we "needed" a plug-in Prius. Then I came down to earth and ran some numbers.

Even with so many short trips, we still average around 50 mpg and only "fill" our tanks (appx. 6 to 7 gallons) about once a month. Given that, our fuel savings would only amount to about $101 per year. (At $6 per gallon we'd only save $220 or so per year.) As it is, we can drive our current Prii for years and years and never give a thought to the money spent on fuel. So, from a purely economic perspective, we will gain no real advantage by getting a plug-in.*

Darn - I really wanted a good excuse to get a plug-in Prius, too.

*Except when you consider (a) the fun of driving in EV mode, (b) satisfying our "need" for the coolest tech gadgets, and (c) saving the atmosphere and other scarce natural resources. (And wouldn't the world be a better place if there were half as many gas stations dotting the landscape?)