87 MPG(e): Toyota Confuddles PC experts

It appears 87 MPGe and the blended range are based on the 5-cycles test. However, only 2 cycles are used to determine AER.

Without the blended range, we can't get the UF to calculate the combined composite figure.

If the blended range is double the AER, UF is 0.53. That'll raise the combined composite to 64 MPGe.

 

I can't tell from the graphs, does the procedure give guidance on acceleration rate? Even staying under 60 mph you'll still use gas in the first few feet if you stomp on it.

 

I am using the term blended mode for 87mpge in the charge depleting range estimated to be 15 miles. The epa will run their tests until the gasoline engine starts under low acceleration then use electricity and gasoline to determine mpge. That is why I thought you posted the graphs. I don't have a clue on the composite calculation, but it should be close to the volts 60mpge, and this figure is highly dependent as you say on cd versus cs miles. During this CD range 87 does not make sense unless some gasoline is used, that would relate to 5.8kwh used to recharge the 4.4kwh battery.

The epa procedure does include acceleration guidance that testers need to follow. The European procedure does also, and acceleration is even slower but top speed is faster.

 

I only have UDDS power at the wheels. FTP is similar to UDDS with additional repetition of the first 505 seconds at the end.

That spike at 200 sec does not exceed 35kW at the wheel so HFET power requirement should max at around 40kW. Prius PHV MG2 is rated 60kW but that's not at the wheels.

 

The new Prius Phev will allow true EV operation and performance for up to 15 miles at speeds up to 62 mph

How can this mean anything but 15 non-blended AER? (Copied from cleanmpg's thread, but I think it is just a quote of Toyota's release.)

 

Again - blended PHEV is an EPA type definition for the sticker, which means the car uses some gas in charge depletion mode. This is doesn't mean they are blending some charge sustaining mode miles. Yes the motor is powerful enough to stay in EV mode, but Toyota's battery or software will cause the engine to turn on during acceleration. The car isn't out so this may change, but this car was always blended phev. To put the number in perspective 15miles/(87mpge)*(33.7kwh/g)= 5.8 kwh at the plug to charge a 4.4kwh battery. Now the epa tests inflate by .7 but this is still too much electricity unless the charger is very inefficient. For comparison the leaf calculation is 73/99*33.7 = 24.8kwh to recharge its 24kwh battery with presumable larger state of charge. When toyota lists the official numbers either the range will decrease, or more likely there will be some gasoline used.

My best guess is this number will be around 4kwh and 0.05 gallons of gasoline to go 15 miles in charge depletion mode.

 

Yikes I am lost, except I think you guys are saying the 87 MPGe figure is not the combined composite like I said above. So I corrected it below.
I give up on assigning values, but I think you are saying xx=87, which is what I thought at first.

PRIUS 2012 PHV (expected)
MPG (Hybrid) = 49 Combined City+Highway
MPGe (EV) = xx Combined City+ Highway (not yet disclosed)
Utility Factor = yy% (not yet disclosed)
MPGe Combined Composite = zz MPGe on sticker

>>The other things I think I can say:
(1) Window sticker will look different in 2012 compared to Volt 2011 (so the 87 figure may not be on the sticker this year)
(2) No one on whole WWW has yet showed how EPA got exactly 60 Combined Composite for Volt in 2011 using 58% UF ??

 

What won't be on the 2012 sticker is the combined composite number (the 60 mpge on the 2011 Volt)

 

It should be like this

MPG (Charge sustain) = 49 MPGCombined City+Highway
MPGe (Charge depletion) = 87 MPGE Combined City+ Highway (not yet disclosed)
Charge depletion range 15 miles
With the caveate of these being initial estimates and may change by the time of production. The prius v was estimated at 40, but ended up being 42.

This compares to leaf charge depletion 73miles @99mpge, and volt charge depletion 35miles@93mpge - charge sustain 37mpg(35 city, 40 highway).

I don't know if the epa is doing a composite next year. It wasn't on the blended mode example sticker.

 

I don't think it will. It is not requiring car manufacturers either. I was doing it to compare with Volt's composite figure.

 

AG/GW- OK thanks I am catching on. But I thought we were expecting Prius PHV to have 100+ EV MPGe. Does the fact that the Prius value 87 is less than 93 for Volt reflect that it takes more kWhr to move the Prius the same 1-mile in a hypothetical 100% EV mode (less electrical efficiency or heavier car etc)? Or is it because more gaso is being used in the Prius 87 value, due to the lower EV range/smaller EV batt?

 

But lets make another assumption, if I was in a more metropolitan area visiting 3 to 4 clients a day where even 120 v charging was available, I might get 6 hours of charge on the road to go with the full charge overnight so 50 miles a day of EV might be doable. Toyota says 2.5 to 3 hours to recharge completely, my average client sees me for 2 hours.

But yes, if you let it sit for 14 hours, drive it to work and let it sit for 8 hours, and drive it home, I question how financially wise it might be.
The Pizza delivery guys could be recharging on 240V between runs.

(I watch the guard drive around the perimeter of the local prison all night and think how much cheaper that would be in a Prius, it is not like they could outrun you on foot)

 

I think 15 miles is using the urban (LA04?) cycle lke the 100 mile range of Leaf (and 40 of Volt).

 

I don't think any sensible people were expecting it to be much more electrically efficient than a Leaf (99mpge).

I don't know enough about the protocols to know how the actual numbers will come out. But it seems to me that most drivers will experience some gas use in the CD mode, either accelerating up an on ramp or merging into traffic or cruising down the freeway.

The real world range people get in CD mode is going to combine a lot of electrical use and a little gas use, thats the blended 87 mpge. If you worked to keep acceleration mild and speed low you'll probably see actual consumption numbers considerably better than that, but then again there is nothing unusual about using special techniques to beat efficiency ratings (hypermiling).

What I can't get is if you are the type of driver with very short commutes and no need to go highway speeds, it seems your best bet would have been to get a neighborhood EV 10 years ago. Seems like an odd niche to target.

 

If you focus on fleet average combined composite MPGe (which is hard since it may not be on sticker anymore) then the Prius PHV and Volt seem to achieve similar results. But for fossil-fuel equivalent calcs, I would rather be told on window sticker 100% EV MPG/efficiency and 100% gasoline/hybrid MPG/efficiency, and the % EV mode (utility factor) and then I can sort it out.

 

But that is more or less what the new sticker does.

The three key points displayed are the CD mileage (87 mpge for the PHV, 93 mpge for the Volt), the CS mileage (49 mpg for the PHV, 37 mpg for the Volt) and how long you can expect each to last on a full tank/charge.

Everything else is for you to sort out.

If you look at the bar graph for CD range and think "most of my driving fits in there" then use the CD number. If you think "that will only meet about half my driving needs" then average the CD and CS together evenly.

Giving a government determined UF is not as useful as just giving you the data and deciding for yourself what works best.