raygundan

I'll correct myself a bit-- the Prius and Volt have the input and output connections to the planetary gear set flipped. And the Volt has three clutches, not just one. While I was thinking the Volt layout was a pleasant surprise, i'm not sure how I feel about three clutches. That seems like a bad idea.

The article author (Eric Loveday) is mistaken about the Prius when he says "But, unlike conventional hybrids such as the Toyota Prius, the Volt would not function without its electric motor."

The Prius in particular cannot move without its electric motors. Some hybrid arrangements (like the original Civic Hybrid) can, but the planetary gear arrangment Toyota uses is more than a little like the one in the Volt.

Volt: http://gm-volt.com/wp-content/uploads/2010/10/voltec-propulsion.jpg
Prius: http://eahart.com/prius/psd/

The volt's got a clutch the prius doesn't that can disconnect the engine, and that appears to be the only real architecture difference. Two motor-generators and an engine coupled through a planetary gearset. The rest of the difference is in the size of the pieces-- the volt's got a larger motor and battery.

As has been pointed out, the Volt's final drivetrain arrangement is (much to everybody's surprise) almost identical to the Prius and its planetary gearset, including the ability for engine power to mechanically drive the wheels (and the requirement that the electric motor keep turning while this is happening, just like the Prius). There's nothing wrong with this, but it's not quite what most of us thought was going on under the hood.

The prius can't move without its electric motor either. The planetary-gear arrangement that both the volt and prius use instead of a transmission prevents this. The volt's primary differences are that it has a clutch between the engine and the planetary gear system, so it's not always connected.... and the battery is substantially larger. The first is almost a moot distinction, since the Prius' motors allow the ICE to remain at 0 rpm well into driving speed. It could be argued that the clutch allows reduced friction by disconnecting the ICE at low speeds, but Toyota's arrangement just uses RPM ratios on the electric motors feeding into the planetary gear system that leave the ICE nonrotating, so there's no loss anyway.

The gearset is somewhat confusing, but this interactive animation helps somewhat:

http://eahart.com/prius/psd/

Initially, we all thought the Volt was a series hybrid, which is just another name for "electric car with a backup generator." It turns out it's a series hybrid with a clutch that turns it into a parallel hybrid at high speeds, which only makes sense. It's silly to route power through two lossy stages (engine->generator->motor->wheels) rather than just applying it directly to the road (engine->wheels). But GM's dug themselves a hole-- they tried hard to differentiate their design from other hybrids, but it turns out to be a very small variation on the theme. Nothing wrong with that-- but it's given them a bit of a PR black eye.

@tylersmyler

Yeah, that's my thought too. The ULV i7 would have been just fine in this chassis, and substantially more useful at more than 2GHz. I checked some benchmarks, and this processor is slower than my ancient 1.6GHz Core Duo. Which, incidentally, is a 32 watt CPU in a 12" laptop chassis *with* an optical drive and a discrete video card. From 2006. If it fit in 2006, there's no reason an 18-watt i7 shouldn't fit today.

It doesn't hurt that the UK gallon is larger, or that the EU fuel-economy test returns consistently higher numbers than the current US/EPA tests. Bring the same car to the US, and giev it the EPA tests, and it won't get 70mpg anymore.

Adjusting for the difference in gallons alone drops the number by 17%.

70mpg (UK) = 58mpg (US), and this ignores the test differences.

Similarly, the tests are different. Take the 2010 Toyota Prius, which is essentially identical in all the markets it is sold in. In the US, it is rated at 50mpg. In the UK, it is rated at 72.4mpg. The difference between ratings, owing to both the different gallon and the differences in testing, is more than 30%. This is the *same car*. This is why we don't see 70mpg cars in the US. They wouldn't *be* 70mpg cars here.

It's probably not just stopping in Long Beach. It will likely go up the coast and make a few more stops to drop off cars-- it's easier than dumping them all off and then shipping them overland to Oregon.

@kjb434

Some CFLs are dimmable. To identify them, look for the word "dimmable" on the box.

Man, it makes me feel old when I have to point out that there's almost nothing "new" about this besides the brand name. Growing up, there was a kid in the neighborhood with a scooter that worked like this, and it would have been built in the 1950s or 1960s, judging by the styling.

I'm with the first commenter-- which is it? Energy or power? And if we're talking about power, is it output or input? 20x the energy capacity would be an earth-shaking breakthrough. 20x the usable power input would be worthwhile, and would enable a much greater recapture of energy when braking and very high-speed charging. 20x the power output would be mildly interesting, but mostly useless unless you think we need twenty times the horsepower in hybrid car electric motors.