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Toyota 1/X Plug-In Concept Makes North American Debut At 2008 Chicago Auto Show

Toyota brought its 1/X (pronounced “one-Xth”) plug-in hybrid concept vehicle (earlier post) to 2008 Chicago Auto Show (6-17 February) for its North American debut. The Toyota 1/X concept made its world debut at the 2007 Tokyo Motor Show.

Comparison of 1/X Concept and Prius Specifications
 1/X ConceptPrius
Total length (inches) 153.5 175.0
Width (inches) 63.8 67.9
Height (inches) 55.5 58.1
Wheelbase (inches) 102.4 106.3
Curb weight (lbs) 926 2,890
Seating capacity 4 5
Engine displacement 500 cc 1,497 cc
Battery chemistry Li-ion NiMH

The hybrid powertrain in the ultra-lightweight 1/X combines a home-rechargeable lithium-ion battery pack with a 500cc flexible-fuel engine in a system that is 1/4th of the total weight of the Prius powertrain. The result is a vehicle with the possibility of traveling more than 600 miles on a small four-gallon tank of fuel and achieving acceleration performance equivalent to that of the Prius.

The 1/X features an aerodynamic ultra-lightweight design that maintains the interior space of the Toyota Prius hybrid and is approximately one-third the weight of the Prius. Its 926-pound curb weight is partially achieved through the use of a light but very strong carbon fiber reinforced plastic (CFRP) throughout the body frame.

The aerodynamic shape of the 1/X and unique cabin design result in smaller pillars, allowing passengers more visibility and helping to create a greater sense of openness and freedom with its outer surroundings for driver and passengers. The CFRP material is lighter and stronger than traditional metals, creating a shock-absorbing like structure with cross-sections that help absorb energy during an impact.

The 1/X roof is produced from a bio-plastic made from environmentally-responsible material derived from kenaf and ramie plants. The result is a roof that improves heat insulation, emits less carbon dioxide, increases the amount of light entering the cabin, and reducing noise.

On the inside, the 1/X employs four ultra-lightweight seats made of polyester fiber that is knitted three-dimensionally for added comfort. The material functions like a spring or damper that helps create a cushion-like feel for all occupants.


Too flippin' cool! They don't give a mileage claim exactly, because we don't know how much motive force comes from an electrical outlet, but it's got to be pretty good.

They don't give a cost target, which is a bigger concern. CFRP ought to be able to achieve economies of scale...but still, what would it cost? The Audi A3 made of aluminum was considered a luxury subcompact and that didn't really sell.

Then again, if the CFRP is ultimately cheaper than the extra Li-ion a heavier car would need, maybe it solves many problems at once.

This could be the car many of us have been hoping for.


if this car will get 85mpg,
and be secure like a new fiat 500

then i will pay 20.000 euro for it


Definitely the future, Toyota is on the right track unlike GM with its heavy serial plug-in Volts. Using Composite, not only the car will have better mileages, but also will requires much less energy to be build. Lighter means less battery needed then makes the plug in revolution more likely to happen.


Anyone know the all-electric range of this sucker?


It's a concept car (yawn!). If I had a penny for every time we heard about another concept car making it's debut I'd be able to build my own electric car!

We now return you to our regular programming!


Just a thought:

Lighter vehicles are much easier to stop, right? They are also (generally) more fuel efficient so....

Why not try to pass safety legislation mandating stopping distances? A legitimate argument can be made that reduced stopping distances would greatly improve safety. This would force manufacturers to either lighten their cars or install massive (expensive) brakes and (expensive) sticky rubber.

Last I read about the next-gen prius was that it was to use a larger engine, more powerful electric motor, and an improved battery. The whole drivetrain is supposed to cost half of what the current Prius' costs.

The engine, if I recall, is supposed to be near 2.0 liters. This seems like a step in the wrong direction, but perhaps somehow it can achieve better fuel efficiency by running at a lower RPM and reducing losses to the cylinder head?


Heh, great concept. But at 20k Euros it's a luxury car for the rich green yuppies. And no mention of the MPC or e-motor specs. And then there is this perplexing idea:

"The result is a roof that improves heat insulation, emits less carbon dioxide..."

Just when did car roofs become CO2 terrorists?

@ Sulleny,

I think they mean using bio oil for the plastic in the roof emits less CO2 than using dinojuice. Yes, I think that's kind of lame, too.


In response to "It's a concept car (yawn!)." Toyota has a pretty good track record of turning concepts into production models. The ultimate cost of CFRP should be cheaper than steel. Its all in the tooling. CFRP only requires 2-4 tonnes of pressure for molding panels, while steel requires above 20. this makes for much cheaper plants. The plastic can be coloured, so no paint shop. The actual material requirements are cheaper as well.

This paper has a good explanation.


Surprisingly, Toyota recently claimed that using carbon-fibre was a no-no because it used so much energy in its manufacture (and can't be recycled) that the energy/CO2 input in its creation can not be reclaimed back by the corresponding improvements in fuel economy.

At the same conference they did say that the energy balance for aluminium was good though.


Although this is just a concept car, it does show the strategy of weight reduction is very viable. Even a conservative 1/3 weight reduction would already be beneficial to non-hybrid car models, for example minivans and SUVs.

OK. Yet another tech area identified for lagging US car makers.

Carbon Fiber Reinforced Plastic probably has different math than the kind of Carbon Fiber used in airplanes. CFRP usually just uses CF rods, kind of like rebar in concrete, inside molded plastic. CF rods can be made in bulk at relatively lower prices, and molded plastic can be much faster and easier to make. I think the EROIE for CFRP is substantially better than for just CF, so my hope is that this is doable near term.

Minivans and SUVs have very high frontal cross they use a lot of fuel just pushing wind out of the way. If you're going for fuel economy, low and long is better than tall and stubby.


It is good to see this kind of progress even if it's only a concept at this point. Kind of reminds me of Silicon Valley in the late '90s. All a good thing! Months and months of breakthroughs. Perhaps the auto makers are finally getting it. Colin Chapman would be proud to see his statement of "adding lightness" finally soaking in.

Stan Peterson

There are no current ways to recycle scrap carbon fiber plastics...

There are no current ways to recycle scrap rubber tires either...

Just what the world needs, a mostly non-recyclable automobile...


In many ways, the Toyota 1/X is a preview of the next-generation Toyota Prius.

While of course it won't get the carbon-fiber body (due to rather extreme costs in production even if you factor out the recycling costs), you will see things like more use of high-strength steels and aluminum body parts to lower body weight, true plug-in hybrid operating mode with a safer Li-On battery pack, and improved aerodynamics. The possibility of 65+ mpg in the EPA combined fuel economy test cycle (2008 standard) may not be far-fetched.

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