Prius Plug-in Hybrid Gets Improved 95 MPGe Rating

The release of data is a bit odd. Shows up on various part of their web site but I could find no release? Did I miss something? (Best I could find was
http://www.toyota.com/byt4/2012/prius-plug-in/en/condensed_ebro.pdf)

But others were talking about 273 kwr/m number being reported but I could not find that number nor what it means.

Was there an overall MPGe (i.e. combined CD and CS mode) according to EPA? (I never figured how they did it for other PHEVs. I wondered if they were using http://www.nrel.gov/docs/fy09osti/46251.pdf but was not sufficient data to determine for sure.

 

That is one possible equation, but more importantly, that formula ignores the fact that the pure EV mode was measured with a less agressive cycle and the blended mode uses gas for the most agressive accelerations/speeds. Thus the number cannot be compared to Wh/mi from any other test.

While John170a likes to say we should report kwr/mi and gallons use, that pair of numbers is only meaningful if tested on the same energy computations. Otherwise you get 2 numbers that cannot be compared to any other set of numbers.

 

I think the EV/HV ratio is a great way to look at it as well. You can ration the battery power carefully to maximize the EV miles. You can also recharge frequently to boost the ratio.

I think 50/50 lifetime EV/HV ratio can be achieved.

 

We know for a fact that numbers derived from dissimilar sources are meaningful. The real-world data provided by owners has been what swayed others to become owners themselves. In other words, they don't actually require the precision you're aiming for... because they know how far off estimates can be from real-world.


Remember, most people don't have their own data to compare with anyway... despite having driven their vehicle for years. Marketing is far more complicated than just presenting some compare values.


How much is ULEV verses PZEV worth? What about the MPGe estimate? Then there's the issue of vehicle size. It's all a jumble of factors influencing the purchase decision, not just efficiency alone. Some people won't have the opportunity to ever use a 240-volt charger either.

In short, for the technology to move from niche to mainstream, those other factors must be included.
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I stand corrected. Numbers from dissimilar sources are useful for marketing as they can allow people to reach different conclusions that someone finds useful, even if the conclusions are technically incorrect. Misleading data is often very useful for marketing. So while you complain about Volt owners posting MPG without listing kWh, it is okay for Prius Promotors to compute kWr ignoring gas. I am quite sure we'll see Prius PHV owners posting just MPG values (ignoring their electricity users their power used. Why, because it good for marketing.


The intent of comment was that if one wants to address actual "efficiency", there are many different models/metrics that can be used, but they all require that the measurements be on comparable setting. So I'll be more precise -- reporting kWr and/or gallons used on any non-standardized test makes them anecdotal data useful for marketing, positioning and providing an example. Anecdotal data is not for engineering or scientific comparison.

 

Utility factor is a well known concept and it is fraction of all miles done on the alternative fuel. The ratio EV/HV ration is unstable (when HV --> 0 it blows up). The utility factor, EV fraction or percentage of miles on EV is always stable. (But calling it a 50/50 split is not a ratio and is fine)

Sure, and I would not even be surprised if a few individuals can achieve even much higher EV fraction in a Prius PHV. Using the SAE formulas, however, one can expect something like 20%EV/80%HV with the Prius PHV CD range. (I don't know how to convert the currently unspecified blended "CD" range into actual EV%. )

 

The spin is getting really bad...

http://gm-volt.com/forum/showthread.php?11729-Plug-in-Prius-11Miles-quot-Blended-quot-EV

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Volt enthusiasts have been attempting to force PHV into an EV perspective for years, disregarding entirely the purpose of the plug and extra capacity.

But no matter how much that continues, sticking to GALLONS and KWH avoids misrepresentation.

You simply state fuel consumed for the distance traveled.
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Toyota specs: 11 miles EV driving range

Toyota now lists 11 miles EV only range at Toyota.com/plugin! I was expecting 15 miles. I really hope that this is due to the 62 mph max EV speed requirement for the US.

I do not plan on driving that fast in EV mode, and hope to get closer to 15 miles.

 

It seemed quite ballanced

Some one called you a name, but I don't think they were unfair at all to the phv.

 

I'm glad that you are getting the car that you want from toyota. I'm sure you will exceed epa, as you seem to be able to do that regularly on your current prius. Let us know what your usage is in winter and summer.

 

As of the time you posted this, the comments were fair and reasonable, in my opinion. I did see the link there to your postings at gminsidenews.com. I hadn't realized you were spending so much time there harshing on the Volt.

 

The spin about sales all throughout 2011 was endless. Each month came with a new excuses, rather than finally addressing the need to meet mainstream pricing.

I kept reminding them about Two-Mode history and what was currently unfolding with Cruze. They turned it around to make it seem like I was defending Prius, even though the focus was on Volt.

It was intriguing to watch more and more of their own members stating the very same thing. They saw the internal competition from within GM itself and a situation very different for Toyota.

The intent with Prius is to phaseout traditional production by offering a variety of clean high-efficiency choices as replacements. The opposition has come from those who thrive on standout vehicles, rather than oridinary business-sustaining cars like Camry & Corolla.

I found it quite informative, providing lots of argument points long before PHV rollout. They (obviously) enjoyed having a scapegoat available. Oddly, it worked out to be a constructive exchange.
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I average 50, exactly what the EPA estimate states, despite just driving it rather than embracing hypermile techniques.

With seasonal variances, we'll see similar ups & downs from PHV.

But keep in mind the rhetoric, which thrives on lack of detail, went on all throughout 2011. That's why real-world data is so much more important than estimates.
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Do you think EPA will report grid electricity per 100 miles on their sticker for Prius PHV like they did for the volt?

If yes, I am trying to estimate what this number will be.
We know: 11 miles blended CD mode, 95 mpg(e) blended CD mode.
Assuming only 42 mpg when ICE is on in CD mode (not up to working temp), assuming also 1 mile with ICE during test in CD mode. The equation is:

11/(10X/33.7+1/42)=95 X being kWh/mile

This gives X=0.31 or 31 kWh/100miles from the wall.

If it is only 0.5 miles with ICE than it calculates to 33 kWh/100miles.
If it is 1.5 miles with ICE than the sticker should show about 29 kWh/100miles.

What do you think?

 

Those seem like reasonable possibilities. Unfortunately, we just can't know unless Toyota or the EPA releases the gasoline consumed during the test. It has to be at least the amount of gas consumed during the basic warm-up process. That used to take about 55 seconds, I think, in the 3rd gen Prius but has been tuned for the PiP down to 42 (but possibly using a touch higher gas rate for a higher RPM).

Does anyone know what this warm-up consumption is in the 3rd gen Prius?

The PiP does not warm up in advance but starts the engine to contribute right away when additional power is needed or at speeds above 62 but most people seem to be assuming that once it starts it will complete its warmup phase even if extra power is no longer needed. Having it contribute under some torque load when cold may well cause it to operate less efficiently than 42 MPG. Maybe more like 25-30 MPG? I do not know. The warmup phase is something that will also take longer in cold weather.

I'll guess this means about .03-.05 gallons for the warm-up and extra power needed for the test but that's not based on any hard numbers.

 

Re: Toyota specs: 11 miles EV driving range

In a mild climate, I find it easy to exceed the EPA range and kWh per mile efficiency estimates by around 20% whereas with similar effort I can only exceed the gasoline highway estimate by around 5-10%.

For example, the EPA range on the Volt is 35 miles but I get low 40's on an annual average and around 47 miles of range driving my typical work commute 9 months of the year. Similarly, the EPA estimates a combined 36 kWh per 100 miles but my annualized average is 30 kWh per 100 miles and would be 28 kWh if I charged at 240V instead of 120V due to lower charging loss.

I expect similar things will apply to the PiP. Many people will be able to avoid the engine startup during EV mode and get 13-15 miles at city driving speeds. I'm curious how far it can get at a steady 60 MPH on the highway. My guess is 10-11 miles until the engine starts (although there will continue to be additional blending after that) based on what we are currently assuming about the battery.