Production GM Volt teaser pic....

[Dr Mordrid]

They've finished the re-do necessary to get the lowest drag & maximum mileage so Ed Welburn, GM VP Global Design stated today:

“I’m proud to say that after extensive aero development of the Volt, and more to come, we have achieved a vehicle that had a coefficient of drag that is more 30% lower in drag than the original concept,”

Production on top, concept car below for comparison.

[MultimediaMan]

Looks like a Dodge Charger - funny double-entendre' considering....what's with the grille?

[az]

Looks like a Saab.

I wonder how they were explaining how to roll down the windows in the concept

BTW, a lot of the reduced drag is probably due to all the grilles being closed (which several "eco" variants of other cars had done to them as well - VW Polo, for instance).

[Dr Mordrid]

The 1L IC range extender needs so little cooling they do it with a small scoop under the bumper...no need for the drag of an open grill which is now just a styling feature. Same reason they closed the scoops on the front corners. If they wanted to the whole front could have been solid save or the scoop under the bumper.

[Nowhere]

I'm sorry, but aren't the ones in the corners more for cooling, like...brakes? (and in the future electric engines in the wheels I guess, so that means also scoops in front of rear wheels?)

Generally...I hope someone will folow this "fancy" car with something in style of city cars...

(hm, gotta check what's owned by GM)

edit: so...there's a chance of this showing up in european "Deawoo/Chevrolets" (yuck), Saabs (ok, even the smallest 9-3 is not exactly a city car, but it's on top of my "mostly normal" car list ) and...Opel. I can definatelly see Corsa & Astra with propulsion system like that...

[Dr Mordrid]

No, not for cooling brakes. Using hydraulic brakes is inefficient as it turns mechanical motion into heat that just bleeds away.

The Volt and most of the coming electrics and hybrids use regenerative braking; the electric motor is switched from being a motor to being a generator and it slows the car magnetically with the energy produced being shunted to recharge the battery.

The hydraulic (or in some versions: electric) brakes are only engaged if a high power stop is necessary and/or for terminal deceleration. Electric brakes & steering are being looked at hard by a lot of companies, especially GM for its skateboard uni-chassis. Skateboard would have all the drive works in an enclosed chassis under the floor and use "drive by wire" similar to how planes now work.

Being so modular skateboard would also be capable of swapping bodies if you chose to do so. Imagine having a sedan at home but a pickup body in storage for when you need a cargo vehicle. 20 minute swap (photo of them doing it with an early prototype)

GM is planning on using E-Flex (the system used on Volt) up and down their line. Interviews in our local papers make it clear they're betting the bank on it. They developed two modular electric drive trains (conventional layout and the skateboard) and set about working on "range extenders" that will plug into that system; a gas/E85 flex-fuel, a diesel/bio-diesel and a fuel cell.

The truth of that came when they tossed several years of development worth billions on 'normal' cars due to come out in the 2007-2010 time frame then put more billions into Volt and its stable mates. Then they moved or hired over 900 engineers into Volt and developing fuel cells.

[Nowhere]

STill...engines in the wheels will need cooling (and you can see clearly disc brake in above photo...)

[Dr Mordrid]

Electric brakes are disc brakes.

And the motor for volt Von't be in the wheels, that'll be for the Skateboard vehicles to follow which will be fuel cell powered. Volt has a 1,700 lb/ft flux-vector controlled 3-phase AC unit mounted in front with direct drive; no tranny. Cooling by way of the under-bumper scoop.

[Elie]

what the HP again? and the 0-60?

Thanks

[Dr Mordrid]

0-60: reports vary, but average 6.something
Top speed: 120 mph/100 mph cruise
Motor: 160 bhp/120 kw flux-vector controlled 3-phase
Voltage: 320v - 350v
Charge: 6 hrs @ 120v/3 hrs @ 220v
IC Range extender: IC (1L 3 cyl turbo) gas/E85 or diesel/biodiesel) or fuel cell (announced for 2011)
IC Range extender RPM: 1500-1800 rpm (3200 rpm max)
IC Range extender generator: 53 kw
Range (Battery): 40 miles to 50% charge with current set, likely more in 2010
Range (Battery + IC extender): estimated 700 miles (more possible with improved batteries)
Brakes: electro-hydraulic
Steering: electric variable rack & pinion

Full prototype is due between April and June '08 with the mules (Volt running gear in a Malibu) running until then.

[Nowhere]

Still...the ones in the picture looks hydraulic

More seriously...I guess I simply dislike the whole scoop thing...what the engineers really didn't know they're not needed? They knew but thought they look cool? They removed them but...still think they look cool?...

[Dr Mordrid]

Electro-hydraulic brakes, AKA 'brake by wire', look similar but work different. Full pressure is available at the wheel at all times, but electronics control its application for braking, a form of ABS, traction control and brake drying (automatic slight pressure on wet brakes to dry them).

The vents were pure show-car stuff, just like the 20" rims which will also go bye-bye because the big wheel wells increase air drag.

[az]

Still...the ones in the picture looks hydraulic

More seriously...I guess I simply dislike the whole scoop thing...what the engineers really didn't know they're not needed? They knew but thought they look cool? They removed them but...still think they look cool?...

This "closed cooling vents" thing is done by other car manufacturers as well, still for design purposes many retain a grille because they don't know what else to put there

[Nowhere]

Uhmmm...how about...nothing? (not "nothing" as in literally nothing of course )

OK, I can understand it in case of options/etc. (my Megane has two, small, wierd looking "closed cooling vents" meant as a place for anti-fog lights ), but this car won't have "normal engine" version, right?


@Doc: oh, I thought "electric brakes" as in regenerative or, in more extreme situations, putting electric engine in reverse, I wasn't aware of such development...but personally I'd still call these "normal" brakes. Yes, drive-by-wire, and I guess this simplifies implementation of traction control/etc., but identical mechanism of operation.
Seems nice development overall...

(hope they'll be damn sure of reliability...vehicles should remain perfectly capable of braking even after massive failures)

PS. Don't tell me all of this doesn't need cooling, unless they menaged to pull 100% efficiency (actually I would welcome that development )

[Dr Mordrid]

Regenerative braking is part of the package, and cooling can be done without huge vents in the bodywork.

The biggest heat sources in an electric like Volt will be the recharger IC (not as much there as you'd think; 1L designed for thermal efficiency) and the batteries. Cooling will be very different as word is they'll use heat pipes to capture recharger and battery heat for the HVAC system when it's needed or move it elsewhere when it isn't.

Even HVAC is to be different: it'll use CO2 instead of a conventional refrigerant. CO2 works very well, in fact it was the predominant cooling gas before Freon, but fell out of favor because it required high pressure lines. With new materials that isn't so much of a problem anymore.

Most of the major suppliers are developing CO2 HVAC units for electric cars including the suppliers for GM, Ford, Toyata etc.