Toyota 1/X (say: One-Xth) concept car - curb weight 926 pounds - Fuel Economy, Hypermiling, EcoModding News and Forum

NeilBlanchard · 12-15-2009, 12:00 PM

Hi,

I have not seen this drool-inducing concept car mentioned on EM.

Chicago 2008: North American Debut of the Toyota 1/x — Autoblog Green

It seats four people. It's curb weight is 926 pounds! It has a 4 gallon fuel tank, and has a total range of over 600 miles!

It is a plug in (serial?) hybrid with lithium batteries and a 500cc flex fuel engine. I'm guessing that it is a serial hybrid, based on the displacement of the ICE, and that there is no mention of a transmission, and the packaging/arrangement of the drivetrain would seem to be easier if it was -- a parallel hybrid would probably weigh more and be bulkier, too.

If they start using chicken feathers to get lower cost carbon fiber, this seems to be a quite feasible car. I'd buy one in an instant!

I'm guessing that this is an updated version of the 1/X:

http://green.autoblog.com/2009/12/14...ncept-vehicle/

Here are the teaser shots, that look like they would fit the 1/X:

MetroMPG · 12-15-2009, 12:24 PM

Thanks, Neil.

(A general request: let's not have this thread slide into another debate about the relative safety of small, light cars. Been there, done that in other threads.)

NeilBlanchard · 12-16-2009, 09:37 AM

I am hopeful that it is a serial hybrid. And there are several big advantages of a serial hybrid:

*Engine can be a lot smaller because it only has to run at one RPM where it is the most efficient.

*It does not need a transmission to spread out its torque band.

*It does not need to have the ICE mechanically adjacent to the wheels.

A parallel hybrid also needs a generator -- the Prius has one.

The battery in a serial hybrid does not necessarily need to be bigger than in a parallel hybrid. It only needs to be large enough capacity to not run low on a charge while the ICE is running.

The advantages of a serial hybrid are that the electric motor(s) are much more efficient than any ICE, and they can be hub motors, eliminating any drivetrain losses. Or they can have just a single reduction gear, which has lower losses than a multi-gear or CVT transmission.

The generator and ICE are directly linked, and can be located independently from the wheels. If the generator is larger than it would be in a parallel hybrid, this is more than offset by the lack of a transmission.

As mentioned above, the ICE can be run at it's designed torque peak, at a single RPM where the engine can be optimized to minimize the internal losses. It can be located in an ideal location for low drag cooling, and since it is a smaller displacement than a parallel would require, the cooling system is proportionally smaller; and aerodynamically minimized, too.

A 500cc ICE also weighs less, and has less internal friction, and it has to pump less air. The (flex) fuel tank is said to be just 4 gallons. It is a flex fuel ICE, so tuning for different fuels is easier when you only have to worry about one fixed RPM.

In comparison, the VW 1L has an 800cc diesel and it is a parallel hybrid -- and it has a 7-speed dual clutch transmission. NO transmission is mentioned on the 1/X. The VW 1L seats just 2 people and it weighs 380kg/838 pounds which is 88 pounds less than the 1/X -- so why does it have a 60% larger displacement diesel with a 7-speed transmission and an electric motor. It needs to have start-stop tech in order to save fuel when stopped. (Of course a serial hybrid has an auto starter, but the timing of it is based on the state of charge, rather than the "request" of the driver.)

The VW Up! Lite is a closer match to the Toyota 1/X (both carry four people) and the Up! Lite weighs 1530 pounds which is 604 pounds more than the 1/X, and it get ~1/2 the fuel mileage. Diesel has ~20% more energy by volume than gasoline.

So, a parallel hybrid that weighs 88 pounds less and carries half the people, and has an ICE that is 60% larger displacement gets roughly the same mileage (170mpg vs ~150+mpg); and the same parallel hybrid drivetrain in a 4 person car that weighs 604 pounds more gets less than half the mileage (70mpg vs ~150+mpg).

Diesel should be 20% better, anyway. And why does it take 60% more displacement and a 7-speed dual clutch transmission? The 1/X carries the same people as the Up! Lite, but delivers the FE of the 1L, with a smaller engine.

Daox · 12-16-2009, 09:48 AM

Thats cool, the 1/X has been around for a while. It looks like it got a redesign since I've last seen it. Very cool car, would cost a crazy amount of money though.

gone-ot · 12-16-2009, 10:12 AM

...anybody else notice the "flat" wheel disc covers with the small "reverse-direction" air-vent (discharge?) cutouts on the black vehicle?

...any 'light-bulb' comments about those cutouts?

thatguitarguy · 12-16-2009, 10:35 AM

Quote:

Originally Posted by Old Tele man

...anybody else notice the "flat" wheel disc covers with the small "reverse-direction" air-vent (discharge?) cutouts on the black vehicle?

...any 'light-bulb' comments about those cutouts?

I'll bite. How about, if they're the same on the other side, then some idiot just put them on wrong and nobody noticed?

Those wheels are tall and skinny very much like MC wheels. And isn't the front set smaller than the rear?

shovel · 12-16-2009, 11:21 AM

I like it... and I like the idea of a lightweight car like this (as long as motorcycles are legal/valid, so should four wheeled spartan vehicles be) - heck I'd be happy to have such a beast with a conventional drivetrain or better yet an external combustion one.

The wheel covers with vents facing "aft" - i dunno they seem to make sense to me. at the bottom of the wheel (as they rotate) they are stationary to the ground no matter what speed you're going because your tread is also stationary to the ground at any given time (no nitpicking about being on ice or doing a burnout) - but as they come around to the top of the tire they're going 2x vehicle speed forward, and presumably forcing air out. That's air being "pumped" out from under the vehicle, which I think we all agree is a good thing right? And by keeping an active flow of air there will presumably aid in preventing the buildup of heat, as well as of brake dust and road gunk on the brakes.

NeilBlanchard · 12-16-2009, 12:34 PM

Hi,

Quote:

Originally Posted by thatguitarguy

I'll bite. How about, if they're the same on the other side, then some idiot just put them on wrong and nobody noticed?

Those wheels are tall and skinny very much like MC wheels. And isn't the front set smaller than the rear?

They go in the correct direction on the other side:

And yes, the front wheels look smaller diameter in the front -- in some of the photos. It is harder to see this in the other photos; the ones from the the front. I think it is a rear wheel drive. We'll see whether the green car in the teaser shots is in fact an updated 1/X or not. It would seem to be either based on the iQ or related to the 1/X, but it could be an all-new design.

Hopefully they are able to produce carbon fiber for less money than they used to -- maybe if they started with chicken feathers? :-)

gone-ot · 12-17-2009, 05:14 PM

...if the motor(s) are at the wheel hubs, then MAYBE those slots are for cooling, but if not, then one has to wonder "why?" for the slots...other than "design."

NeilBlanchard · 12-18-2009, 12:19 AM

I'm looking forward to hearing the details and seeing more complete photos of the new Toyota hybrid in January. And if it is not a updated version of the 1/X, then I'll be hoping for some news about that, too.

If the new hybrid is similar to the iQ, that's fine by me!