Prius Plug-in Hybrid Gets Improved 95 MPGe Rating

The PDF UCbruins linked to says this

So how much gasoline is being used to go those 11 miles? Comparing the EV efficiency is stupid if it is using gasoline at the same time. Sagebrush you know the volt is not a serial hybrid right?

 

Fair point, I forgot that 'EV' in the PiP may be blended. I'll revisit the calculation when the amount of petrol used is known.

EPA estimates 20% wall-battery losses, and Toyota has published 3 kwh to charge the battery from the wall from 'empty' to 'full'. I like battery-wheel, since then we do not have to wonder if one charger is more efficient than another. If cars have electronics *in the car* involved in charging that have different efficiencies then I agree that a wall-wheel analysis would capture those relevant differences.

 

Hey that is cool, so that tells us the SOC swing that Toyota is allowing theoretically.

2.4 kWh charging and the battery I think is 5.2 so they are allowing 46% swing. Lower than 65% on the volt and ~90% on the Leaf.

 

Re: EV range drop again?

Yep, different tests and different ranges (and MPG or L/lm) Of couse that's true for all the comparison cars as well. The Opel Ampera official all-electric range under the EU-approved UN ECE R101 standard for plug-in hybrids is 83 km (52 mi), though the official statement is Ampera's EV ranges is 40 to 80 kilometres (25 to 50 mi), i.e. the same as the translated US range of its american twin-sister, the Volt.

:focus:
Seeing the range numbers that were bandied about on this site, and the hopeful tones when the 95MPGe was announced, the reported 11miles with EV+gas must be a disappointment to many. If I were to hazzard a guess the "optimizations" were to push up the MPGe number to outperform the volt by just a touch, even if that meant lower total range. If it had been 12miles and 89MPGe, toyota would be an even harder time having a dimension to push.

To UCBRUINS, of course they knew. The EPA process for evaluation has been clear for over a year. (Finalized about month before the Volt's testing was done). The fact that they are dribbling out information bits at time is telling. Still don't know the full EPA data and they are slated to be delivered in a few weeks.

 

All of the charging electronics is in the car. The ESVE is a safety enhanced glorified extension cord. And it also makes a difference if you do 240v (the default in Japan, which is the only place I've see 3kw) and 120v (which is what will ship with the car in the US).

 

Re: EV range drop again?

Yes, I thought the non-blended EV range would be higher, but I also thought the usable battery capacity would be about 4 kwh. I'm pleased that the PiP is looking like it will have excellent EV efficiency; range will just be a question (within modest limits) of either putting in a bigger battery or allowing a deeper DoD.

I am not surprised at the relatively low DoD in the PiP compared to the Volt or the LEAF. Toyota engineers the battery to last for the lifetime of the car, while GM engineers the battery to last for the warranty period. I suspect that Nissan is closer to GM than to Toyota.

 

Actually aj John170a points out in this post of thread
http://priuschat.com/forums/toyota-prius-plug-in/showpost.php?p=1472551&postcount=93

The production pack is 4.4 which if the 2.4kw is correct is 54% DOD.

 

drinnovation said

Using 50 mpg/mile for the PiP, this works out to 326 wh/mile non-blended EV mile efficiency in the PiP on a wall-wheel basis.*

So if our Volt owner is right, his car uses 360/326 = 10% more energy per mile in plug-in electric driving.

* 30,000 wh / 91.8 miles

 

If you want me to say that I believe the Prius PHV will have a higher electric efficiency, just ask. I do believe that the Prius PHV be more efficient in pure electric mode case, but don't have enough data to estimate how much more efficient. It has a smaller electric motor, less weight and a better coefficient of drag -- it darn well better be more efficient. (Then again reduced HP is generally more efficient, and a motoscooter would be even more efficient, or even a bike. But that does not mean its what I would want to drive.)


Not sure about your computation. For that matter I am not sure how to convert meaningful from the split gas/EV in a blended test to a comparable number for a pure EV test. As far as I can tell they are incomparable except in a unified energy space (e.g. MPGe). Even if we knew the gas used in the EPA test, its not a comparable number in pure kWr/100m as its only measuring on part of the test. If the electric motor was used to do the EV test, the losses in efficiency, which are non-linear would need to be measured and used to model the energy needed for the conversion. In addition, if the ICE provides more power than needed for the accelerations it would convert the excess energy into electricity inflating the kWr/100m.
I expect in the blended testing, the ICE efficiency is lower (more like 35mpg) but its also doing the hardest part of the trip, but using that to estimate "pure EV' the remaining further inflates the Kwr estimation).


As I though about it more, I'm afraid even with the amount of gas used, the numbers will remain incomparable for pure electric mode. The only space in which they can be compared is overall energy efficiency. The
overall efficiency difference of 95mpge vs 94mpge is about 1% overall tank-to-wheels efficiency difference (and maybe more maybe less, depending on rounding)

 

Re: EV range drop again?

I had estimated the EPA range for PIP to be 10 miles.

http://priuschat.com/forums/toyota-prius-plug-in/100051-all-evs-phevs-specs-dimensions-compared.html

 

Re: EV range drop again?

Once EPA gets the raw city+hwy numbers, they "adjust" it by a 30% factor. That is the reason Leaf went from 100 miles to 73, for eg. But in Leaf's case it is not a bad estimate given that the range drops below that in winter because of heating.

But with PIP, you are likely to get more EV range since battery isn't used for heating (IIRC). Nor can you go fast on EV. That 30% adjustment is a big heavy for PIP - but atleast lets you compare with Volt others apples-to-apples.

 

Re: EV range drop again?

Yep.. you and many others (incude me) were predicting 10-11. But some were in strong denial. In this thread http://priuschat.com/forums/toyota-...ment-in-sun-post-pip-epa-sticker-guesses.html there were people with 20-30 mile blended range estiamtes.


I'm curious. Why not list MPGe for CD in the table (and MPGe for CS for PHEV) in the table? Why not list EPA estimated cost to operate for a year? (The latter is more useful since for many people they really don't understand the reduced operating costs, and so it could matter could be useful for people cross shopping ICE, PHEV and BEV).

 

Hey thanks I hadn't been aware of the change in size. They increased the voltage per cell and decreased the energy of the pack. That is a bit worrying to me in terms of degradation, but we will just have to wait and see.

 

Re: EV range drop again?

The EPA adjustment has adjustment for all cars, not just EV/PHEV. The 30% for PHEV/EV is is to help balance the estimates using just the 2 cycle model compared to the the new 5-cycle model (with US06 and other cycles) which is now being used for other cars. (And if they don't retest, they get a percentage hit). EPAs site says "most vehicles will drop by about 12 percent on average, and by as much as 30 percent for some vehicles".

I've not seen a rational published but I'd guess that because of the complexity and time needed for testing PHEV/BEV, they are not using all 5 cycles yet.

Their estimates for the Leaf and Volt seem to be pretty good -- on average. THeir estimates for other ICE vehicles, including the Prius, seem to be about the same (5-6% high).

 

Re: EV range drop again?

Estimated cost can be useful - I could also add MPGe, though it is mostly useless. Ofcourse, just a small handful of the cars there have EPA ratings.

 

Re: EV range drop again?

Yes, toyota knew about it, and should have included it in their calculation.

The pack size was reduced from the demo car to the production car. The 15 miles electric range was for the production car. Toyota's first report on the production car had increased range with a smaller pack was 15 miles @ 87 MPGe, which only makes sense if you are using more gas in your charge depleting cycle. They then changed this to 11 miles @ 95 MPGe in this latest release. We won't know how much if any gas is used in the 95 MPGe Rcda (charge depletion range) until the next announcement.

 

A full charge takes 3 kwh from the wall. If no petrol was consumed then the petrol(e) is ~ 1/11th of a gallon, and the MPG(e) is 121.

 

I am an engineer (electrical) but I must admit that I find this whole discussion very confusing. I'm just glad that in a little over three weeks I will be able to find out for myself how useful the plug-in EV charge is in helping me consume less gasoline. That is the 'fun' that my money will buy me.

I can't imagine Toyota would have gone through the trouble of adding a bigger battery and plug-in charger (and charge so much more money for the car) if it wasn't significantly better. It sure is a big step in the right direction.

 

The Prius's 15 mile EV turned out to be 11, just like the Volt's 40 mile EV ended up being 35. This number will vary up or down depending on many conditions.

http://life.nationalpost.com/2012/01/27/road-test-2012-chevrolet-volt-offers-a-smart-solution-to-ev-range-anxiety/