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Toyota Ratchets Up Plug-In Prius Talk

By Jack Rosebro

In an interview published in the UK’s The Guardian, Toyota executive Shinichi Abe has been quoted as confirming that Toyota is working on plug-in hybrids, and as asserting that the next-generation Prius will have an all-electric range of about nine miles, or 14.5 kilometers.

According to The Guardian, Abe, who heads Toyota’s hybrid development program, further commented that future Toyota hybrids will be able to operate as mobile generators, and that the company is interested in the addition of electrical charging outlets to traditional gas stations as a step towards a petroleum-free future.

The comments are but the latest in a series of indicators that Toyota is increasingly interested in talking about—and working toward—a plug-in future for its hybrids.

Another UK publication, the Auto Express, recently published an article (earlier post) which included a Toyota engineer’s assertion that the next Prius, due in late 2007 as a 2008 model, is being designed with a fuel consumption target of 94 miles per gallon (US), or 2.5 l/100km.

And earlier this year, when asked by Green Car Congress if the hybrid Camry’s introduction now paves the way for a redesign of the Prius with even more radical technologies (earlier post), Dave Hermance of Toyota replied, “Absolutely.” Hermance made his comment at the third annual SAE (Society of Automotive Engineers) Hybrid Symposium in San Diego in February.

Last year, Toyota exhibited a concept home in Japan (earlier post) that included a plug-in Prius. Designed in cooperation with Toyota’s home-building division, Toyota Home K.K., the Toyota Dream House Papi was touted as an environmentally friendly, energy-saving intelligent house that could interact with other Toyota technologies. The house was designed to be able to use the Prius as its sole energy source for up to 36 hours in emergencies, and to recharge the Prius when needed. At the time, Toyota said that it expected such technologies to be in use by 2010.

In February 2005, Toyota announced plans to lease a modified Prius capable of providing 3 kW at 120 volts to a rural electric cooperative in Oklahoma for field and market testing.



A nine mile all electric range seems a little small considering that an EDrive upgrade on the existing Prius will give up to 30 miles of pure EV range. Why such a small range for a future full production car ?


"is being designed with a fuel consumption target of 94 miles per gallon (US), or 2.5 liters per kilometer."

Am I reading this incorrectly? they mean 25 kilometers per liter?


it is probably a typo, 2.5 liters per 100 kilometers

Jack Rosebro

My editing mistake: the numbers should be 40 kilometers/liter, or 2.5 l/100km. Sorry about that!


I think that they mean 2.5 L/ 100 km. That's the way the Canadians usually report their mileage.


Marcus, I think it's "only" 9 miles in ev mode BECAUSE it's a production car. Costs have to be kept lower, they can't add $10k to the price of the car. Also they'll want to keep their 8-10yr battery warranty. What kind of warranty do you get on the batteries used in the EDrive upgrade?


maybe that is how they will achieve 94mpg, by making an assumption about the expected usage of the vehicle, then counting the electricity as free. if all of your trips are low speed and less than 9 miles, you'll have infinite miles per gallon.

this is valid and true, of course.

i don't expect they'll make a major improvement in highway efficiency. their coefficient of drag can't be reduced much, they already use low rolling resistance narrow tires, and atkins cycle engine.

so, for people in wide open spaces, the next gen prius should have about the same efficiency as the current on. city-folk stuck in traffic will be better off, though


Thanks Eric for your comments

Well if Mitsubish and Subaru really start selling pure EVs that have a range of around 100 miles I think I would go for that rather than the next Prius. Of course its also going to depend on how much gasoline costs in 2008 I suppose. Interesting times....


Be careful that Toyota engineers are probably using Japanese 10-15 mode figures for fuel economy, which leads to much better results : for instance the current Prius versions sold in Japan achieve from 2.8 to 3.0 L/100km depending on the version (different tyres available there) according to this method. So 2.5 L/100km sounds possible to me, but needs to be translated in the real world. Maybe 3.5 L/100km...

Shaun Williams

Aha! I knew it.

Excellent news, roll-on the EV paradigm shift...

A PHEV "zealot".

(Actually, I'm an EV zealot but PHEVs are the crucial transition technology.)

gerald earl

Interesting times indeed.There is nothing more powerful than an idea whose time has come.Im sure many of us took the plug in partners survey which asked would you buy a plug in if it were availlable.The message is getting out to automakers and politicians.The Bush energy bill has energized this push.It was delayed for four years by dems.Partisan politics by both sides will weaken us and empower our enemies.Dems and repubs now have a bill{vehicle fuels choice and security}Go to and you can track energy legislation.Lefty loonies and rightwingnuts act together and call your reps and insist they work together on this legislation.Passage of this would accelerate the adoption of the tech we read about here.Your voice is your most powerful weapon in this fight.We can honor the men in the battlefield by solving the energy dependence that put them there.Energy independence will be cleaner and someday actually clean.There will be a number of steps to get there.Lets not squabble about every step rather lets begin the journey.


This is good, but still frustrating in the baby-step mentality that auto manufactures always manifest. Hopefully, ultra-capacitor tech will rise to the occasion fast enough to give us true EV options that not only have good range, but 6 minute charge-up time. Toyota better keep its eye on this as it would kill the Prius/Hybrid sales dead. Toyota would be smart in making their battery packs easily swappable to accommodate advances in battery technology. Time for the car to become an appliance.

Bud Johns

The Prius stopped useing low rolling resistance tires as of the '04 model year. They use Goodyear integrity tires to this day..........


One needs to adjust those mileage figures to account for the difference between the Japanese cycle and the EPA cycle. The Japanese cycle makes the EPA cycle seem conservative. If one does the adjustment, the expected combined mileage would be about 63 mpg.

I would hope for at least 20 miles electric to accomodate the majority of commuters. Or, why not provide different mileage capabilities as options?

I love that Toyota will have a car, Prius, that stays on the leading edge. We need to keep ratcheting that up so that other automakers have something to shoot for. This, at least, puts a little fun factor in fighting global warming and oil dependence.


It would be progress if they began to ship a Prius to the United States that would have any all-electric miles!

The Prius in Europe and Japan already have such a feature. It was removed by Toyota for North American sales.

I doubt whether the concept vehicle appearing at the dream house was the first plug-in devised by Toyota engineers. It would be interesting to know how long ago they began testing a plug-in approach.


I can only guess that the nine mile range is instituted to keep costs low. My best guess is that Toyota has found a way to reduce the total costs of he hybrid components from $4000 to $2000. If Toyota then adds an extra 2K worth of batteries, this would yield the all electric range of nine miles, and keep the overall cost of the Prius approximately the same as the 2006 model. Keep in minds that the number of consumers who are willing to shell out 35K is a let less then those willing to shell out 25K.

Just my best guess,

hampden wireless

Actually I find a factory plug in 9 mile range GREAT. It will be a game changer if it gets here. Many could buy the car and cut thier gas use down 75% or more over a REGULAR un plugged prius. Yes, not everyone has many trips under 9 miles but many people do.

The highway mpg on the Prius could go up with a gearset that would allow the gas engine to turn off over 45mph. Going downhill on the highway the gas engine does not shut down, so that could be improved.

Sid Hoffman

Someone mentioned that they didn't think the highway fuel economy would improve. One proven technology that Toyota and Honda aren't using yet on their hybrids is gasoline direct injection. So far it's used mainly to increase both power and fuel economy, but if you designed it with maximum fuel economy in mind, it may be capable of up to a 15% improvement in highway cruise. If you currently get 45mpg highway, that would rise to 52mpg - a very substantial improvement.


Further improvements could come from an exhaust energy recovery turbine and/or a bottoming cycle driven by engine waste heat, but the latter wouldn't work well in start/stop duty cycles.


Regarding costs and the nine mile range, I'm sure I read somewhere that even though it costs $11000 for EDrive to upgrade the current Prius (30 miles EV range), if you discount the original battery and take into account probable reductions in battery price due to volume this type of upgrade for Toyota could cost a lot less - something like $3-4000 total. So I'm still not totaly convinced its a cost issue - EDrive say the battery may last 5-10 years depending on how "end of life" is defined. However they don't have details on a guarantee yet.

John W.

Good post Chingy. I wonder what all these start-ups will do to the landscape when they release their products in the next few years. It's gotta stink when a big company puts millions into R&D only to lose cold to some start-up company, but, oh well!

Companies need to add extra battery packs as an option, ones that can be plugged in at the expense of some trunk space, etc. Great option for people with longer drives, and this would be a modular approach that would not cost companies anything extra.

Honda has been the undisputed mileage king the whole time. They will not relinquish their title without a fight. They make the best and most efficient engines by far: if they would only add much more electrical power (b/c it's very minimal at present) they will do wonders I'm sure, esp. if i.c.e. development continues as it has been. The insight has been out since, when, 1999? 7 years basically unchanged! I'm very eager to see their newest high mileage car, whenever it comes out, to keep the competition going. I pray it will be a plug-in with a serious battery pack.

This is way better than watching baseball.

John W.

To supplement my previous post:

If I were a betting man I would bet you could purchase another battery pack from Honda or Toyota, Ford, whoever, and get a (willing) electrician to splice it into the existing architecture. Splice it in in parallel, so the voltage remains exactly the same, but the range is doubled. This could (likely) even trick the onboard computer when it reads the battery as well, as nothing changes except the overall capacity, it would just take a bit longer to charge. No mixing dead batteries with good ones, however: that would be bad. You'd lose your warranty... I don't know what a prius battery costs new, though, so it may not even be close to worth it. Just an idea for high mileage drivers.

Has any crazy hacker tried this trick?

Bud Johns

I moved to Tennessee, and yes, the engine in the Prius shuts off going down the hill even at 70 mph! If the slope is enough, of course. My mileage improved from flat Florida by a good couple of mpg.

Max Reid

9 miles (14.5 km) range is perfect. I read earlier that some companies which convert hybrid to plug-in charge $12K for 60 mile range. So for 9 miles, cost will come to aroun $2K. Thats the affordable by many common people.

9 miles is range travelled by 7 days a week by most people.

Excellent Toyota. With Oil @ $75 / barrel, the time for plugin has come.

Please note that Saturn is going to sell a Mild Hybrid Vue for $2K more than regular Vue.

If Toyota does not make it affordable, GM may steal the show.

allen zheng

Thermoelectric/thermovotaic combo: It'll strip half the waste heat off the exhaust and coolant. Maybe throw in a onboard high themp hydrolytic unit, and you'll boost it by >6%. Total efficiency could rise to >62%. Then you could achieve 98+mpg highway, 110+mpg city (conserative estimate). Add better storage units, and it'll rise even more.

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