Prius Plug-in Hybrid Gets Improved 95 MPGe Rating

I half agree. The car's wall-to-wheel electric efficiency has noting to do with how the electricity was produced. If looking at Wells-to-Wheels, which some like USBseawolf2000 and goria seem to prefer, it does.

But clearly you disagree with the claim that in Jay leno's case the PiP would not be more efficient. I did not add that Jay's commute is just over 35miles each way.. so the PIP would use about a gallon of gas 70/(22/95MPG + 48/50 MPG) = 58MPGe on the commute and it would be lower with any other trips (he did burn some gas on trips). Compare that to 92+ MPGe in the Volt and explain which is more efficient.

Your recent post continue to suggest a deep issue with MPG(e).
I'd like to hear your reason. When I asked before you said it was because MPG(e) it had a political fudge factor. When I showed it did not (in this post you never replied. So again why don't you consider MPG(e) to be an effective measure of the efficiency of a vehicles use of its stored energy?

 

How much gas was typically used (in 'blending')? I don't see how an EV range can be quoted when gas was used.

I'd like to know how many more miles the EV allowed the car to go (compared to how far it could have gone without a charge).

It almost seems like it is unfair for Toyota to compare its EV miles ('blended') against the Volts EV-only miles (when gas is rarely used).

 

For the EPA testing, no more details have been announced over the weekend. Maybe today we'll get more. My guess is not until they actually release the sticker. I wonder if the Honda verdict in Cali had anything to do with Toyota correcting its statements on the web asap
(See http://reviews.cnet.com/8301-13746_7-57370905-48/judge-rules-honda-overstated-hybrid-fuel-economy/).


Don't think of it as "EV" miles.. think of it as "CD" miles and then it seems fair. Overall is 95MPGe for 11 miles, then 50MPG after that. Eventually the sticke will show gas and electricity used in the 11 miles,but from an overall efficiency 95MPGe for 11 miles says it all about the "CD" range efficiency. Just a hair more efficient than the Volt for 11 miles, then much lower until 35 then higher after 35.

 

The problem with MPG(e) is using it to compare different fuels with different energy paths.

Remember the picture of the Rav EV towing a generator? THAT was, and is my answer why I say that a "higher" MPG(e) in that RAV compared to e.g. a Prius is clearly nonsensical; as for the people that then take the higher MPG(e) value of the RAV and deduce that the RAV is more efficient -- well, that is just frank ignorance.

If you want to compare PiP electric efficiency to Volt electric efficiency, then I could not care less if you use units of MPG(e), kwh, or joules -- or any other energy unit.

 

I guess I was naive. I thought I'd get 10 to 15 mikes of pure EV driving if I didn't drive too fast.

I am not nearly as excited about my new PiP as I used to be.

 

i was hoping for 14 mikes. hopefully, we'll have actual usage reporting here before i have to make a decision. i'm also concerned about blended mpg's. for thirty grand, i would like at least 75 mpg dollar equivalent.

 

Forget the MPG(e) nonsense.

Usable battery energy is 2.4 kwh from a full charge.
Battery - wheel energy consumption ranges (ballpark) like this:

Hypermiling uses as low as 0.15 kwh/mile
Gentle driving in the city with smart brake use is 0.2 kwh/mile
Average Merkin driving is 0.25 kwh/mile
Aggressive driving is 0.30+ kwh/mile

So gentle driving gives 2.4/0.2 = 12 miles of non-blended EV driving.

 

You will probably get this (in pure EV) easily, if you are not too aggressive on the pedal.
Even if you evoked the ICE for several seconds, it will return to EV drive soon (once the ICE is not needed).

 

thanks sage, i'm feeling better already!

 

once the ice has warmed up. i'd rather not have that happen. i wonder how much gas it uses per minute?

 

This needs to be verified, could be 2.6-2.7 kWh usable. The number was not announced yet.

 

Toyota announced that it takes 3 kwh to fill the battery from the wall. Charging losses are about 20%

 

Ahh, I see. You don't believe that one should compare efficiency across energy forms at all. This would be very limiting. So the Prius PHV and cannot be compared in terms of efficiency to the Prius. One is not more or less efficient, its just incomparable. If two settings of the Prius PHV use different amounts of gas/electric they are not comparable. Your driving efficiency of a PHV cannot be compared to anyone else's because the gas or electric will not be the same. One cannot answer the question which is more efficient, PHV on electric or gas. The Prius PHV and Volt cannot be compared for EPA tests since one uses gas and the other does not. If someone were to do a formal pure electric test only then could their electrical efficiency be compared.

Your example does not really address the issue -- it is a bad hypothetical example. There is no MPG(e) rating for the Rav4, so we don't know if it would be above the prius. But also the Rav4's rating would not apply to the vehicle when it was pulling a trailer (unless that was how it was tested). Based on areodynamics and weight, I would not expect a Rav4 + trailer to get better than 40MPGe.

Your argument was NOT really about how efficient was the Rav4.. it was complaining about the combined vehicle + generation system. So at a deeper level it seems your problem with MPG(e) is that you don't consider pump(walls)-to-wheels meaningful as a measure of vehicle efficiency and you DO care about how the electricity was generated. (Which contracts some of your earlier statements). If that is your argument against MPG(e), you are not alone. Many consider wells-to-wheels or Life-cycle-analysis better measures. But then one must make assumptions about power/fuel sources and such.

Unfortunately, whether you like it or not, there is a need/desire to compare the efficient use of energy across vehicles of all types. Both Vehicle efficiency (MPGe) and power source efficiency/WHW should be considered. So too should the mile-per-dollar for fuel.

 

Was this announced for the US version?

 

I agree with paradox above, if you don't drive too fast or aggressively you should be able to stay in all EV most of the time, and if you do you should really crush the EPA 95 mpge because gas usage weights that number down (likely towards 50). I wouldn't be surprised if people who can stay 100% EV get efficiency results over 120 mpge.

Its really the problem we've had communicating about these issues all along, there are so many variables (how you drive, the temperature, the terrain, the type of driving, how long you were able to charge, if you were able to charge, etc...) that comparisons become terribly complex. The EPA numbers give us a good neutral benchmark, but won't necessarily have a lot of bearing on how any particular driver does.

I bet you will love your new car.

 

But the Volt and PiP are basically equal wrt electrical efficiency, and under electric power, both vehicles are vastly more efficient than under gas power, because the gas equivalence of electricity is much cheaper than gasoline. Not only is it cheaper, but in much of the US, especially the West, it is greener.

 

It is unknown how electrically efficient the Prius PHV really is. The 95MPGe is a mix of electricity and gas (Because the EPA testing has speeds or acceleration that exceed the PHV abilities in EV alone). People are speculating on its pure EV efficiency and range (which depend on many many things). With care I would expect one can get 12 miles EV in a Prius PHV and 50+ in a Volt (I am 13% more efficient than EPA numbers). EPA numbers are just one point of comparison, though your Fuely results suggest you get below average in your existing Prius, so you may be on the lower side.

I agree that both are far more efficient using electricity than gas, especially if you have a clean electricity source.

The question is which is a better for your driving needs. The Prius PHV will likly be just a little more efficient if you drive locally, calmly and < 62mph and < 10-12 miles a day. It will also be more efficient if you drive > 70 miles a between charges.

 

I don't think there's a contest. The decision isn't PiP vs Volt, it's Hybrid vs. gas-guzzling SUV. I'm a big fan of Volt and Prius and Leaf. But in the technical comparison, for me, I don't know which would be more energy efficient. As you can see, I get about 48 MPG on a Prius which is mostly used for a 90-mile round trip commute over flat freeways. Mileage takes a hit when I'm late for work and on weekends, when my car often hauls my family of five about town. With four more on board, mileage is lower, BUT with PiP, these may be all-electric trips. I haven't yet asked my employer for free electricity. I personally doubt they'll give me free electricity and they won't bother to charge me for it either. They aren't bad people, it's a business and they've got better things to do than deal with the legal and economic and environmental aspects of my new car. I don't blame them.

 

Based on the Japanese and European city-oriented test cycles the PiP seems to be 15-20% more efficient in city driving than the Volt if we believe Toyota's statement that it takes 3.0 kWh to charge. Highway driving is probably quite a bit closer based on trends from the LEAF and Mitsubishi cars city vs. highway EPA ratings.

I haven't had time to crunch hard numbers but I'm going to make a wild guess that the PiP will get 29 kWh per 100 miles for EPA city, 35 kWh highway, and 32 kWh combined.

I'll revise my earlier guess about how much gas was used to get the 95 MPGe estimate and say .09 gallons (instead of my old guess of .03-.05).