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Chevy Volt powertrain muleClick above for high-res gallery

It's been 28 months since we watched Bob Lutz drive onto the stage at Cobo Hall in Detroit and step out of the Chevrolet Volt concept. In the intervening period, a corporate drama of epic proportions has transpired as Lutz has gone into semi-retirement, Rick Wagoner has been ousted as CEO and the U.S. government and the UAW are about to take a 90% ownership stake in General Motors.

In the midst of this corporate chaos, a dedicated group of hundreds of engineers, scientists, designers, technicians and drivers have tried to keep their heads down and out of the line of fire as they worked to make the Volt a production reality. From the time we first saw the original concept, GM has selected a battery supplier (LG Chem), defined the final powertrain configuration and released the production design, among countless other tasks. After more than a year of pestering GM, the call finally came to get behind the wheel of a Volt prototype. Read the results after the jump.



Photos Copyright ©2009 Sam Abuelsamid / Weblogs, Inc.

We arrived at the design building on GM's tech center campus in the middle of a torrential downpour where we were escorted to the executive garage. There we found two of the 30+ second-generation Volt mules that are running around in Warren, Milford and other locations undergoing testing and development. Like their four-legged namesakes, mules are a cross-breed of different vehicles, and because of the lead times and testing required to bring a mass production vehicle to market, development is done in parallel on multiple paths. Automakers build these prototypes by taking an existing vehicle and adapting new components to road test the systems before the complete vehicle is ready for production.



For the Volt program, the first-generation powertrain mules were built using previous-generation Malibu body shells with the Voltec (E-Flex) powertrain -- the so-called Mali-Volts we first saw about a year ago. Those vehicles originally ran in late 2007, with the engine-generator and electric motor as well as a small hybrid battery to start development of the powertrain control system. Later, the full Volt T-shaped battery pack was installed and in 2008, the second-generation mules were built using the body of the new Chevy Cruze. Unlike the larger mid-size Malibu, the Cruze is based on the same Delta global compact platform as GM's plug-in savior, which is closer in size and weight to the Volt and was used throughout winter testing in 2008-2009.



Volt Vehicle Line Executive Tony Posawatz rode with us in the Cruze-Volt and discussed the current state of development. The prototype we drove had a powertrain that was about 80% representative of the final specification, and while the full powertrain was in place, including the 1.4-liter four-cylinder range extender, our time was spent in EV mode only.



Since the Cruze is close to the Volt, packaging the powertrain was less of a challenger than it would have been on a completely different platform. These cars were built up from early Korean-market Cruzes (hence the different grille) and are remarkably well finished. Setting aside the Volt powertrain for a moment, the Cruze seems like it will be an excellent competitor in the compact sedan segment. The interior is attractive and well laid out, and it's exceptionaly quiet inside.

In the garage, the cars were already running, sitting silently with the gear selector in park -- one of the wonderful things about electric drive -- and even though the Volt, like most other EVs, uses a single-speed reduction gear transmission, the shifter is still there to enable park, reverse, neutral and drive. The mules use the stock Cruze instrument cluster, but since the wiring harness was modified, some of the warning lights remained lit throughout our drive. Once we adjusted the seats and mirrors, and verified the warning lights weren't a problem, we moved the shifter into drive and "motored" off.

Out in the rain, we had to crank up the window defogger which, like all other accessory systems in the car, was electrical. Even though electric cars are considered to be quiet, older examples tended to produce whine from the drive motors (see: Dodge Circuit). GM and others have addressed this issue, and to our surprise there was no audible squeal inside the prototype.



The electrically-assisted steering has a nice heft that should make the production version an entertaining steer, although we couldn't judge it extensively on our wet "route" which consisted of two-mile laps on the tech center campus. The braking hardware, based on the system found in GM's two-mode hybrid SUVs, has a similarly firm and communicative pedal feel with no noticeable transitions between regenerative and friction braking. There were a few of minor glitches when we hit a major bump in the pavement while braking, but these will undoubtedly get sorted out as the final calibrations are completed over the course of the next year.

Power delivery is seamless and when the time comes to slow, lifting your foot off the accelerator yields a small amount of regen braking to simulate the coast-down on a conventional vehicle. The transmission shift lever also has a low gear position that induces more aggressive lift-off regen, about 0.25-0.30 g of deceleration -- equivalent to the braking most drivers regularly perform. When driving in stop-and-go traffic drivers could select L and just drive with one pedal much of the time, maximizing regenerative braking and range. According to Posawatz, future generations of electrically-driven vehicles could offer drivers different braking options, allowing them to select the amount of regen they want, but this won't be available on the first run of Volts.



Overall, the electric drive system in the mules performed as advertised and GM appears to be well on its way to meeting a November 2010 Job 1 date. We drove about ten miles in the rain on electrical energy only with plenty of accessories running and no significant problems. However, it's obvious there's a great deal of work to be done between now and the latter half of 2010. Right around May 27, GM will start final assembly of the Integration Vehicle Engineering Release (IVER) prototypes of the Volt; the final prototype stage where the production body work will be joined with nearly all the production-tooled compenents. These vehicles are used for final calibration and validation of all systems.

The bodies-in-white for the 75 IVER prototypes have largely been completed and once these vehicles are built, the engineers will start the final push toward finishing the first-generation Volt. Posawatz promised to have us back for another drive to sample the range-extender in action. Let's just hope that the Volt doesn't become a victim of the financial apocalypse currently afflicting General Motors.





Photos Copyright ©2009 Sam Abuelsamid / Weblogs, Inc.


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    • 1 Second Ago
  • 83 Comments
      • 6 Years Ago
      I really wonder what the real world mileage of the car will be when purely on extended range mode.
        • 6 Years Ago
        The EPA miles per gallon rating is going to be about 100 mpg based on the test that the EPA performs.

        Performance from the electric motors (and their instant peak torque) is comparable to a V6 with 0-60 times in the 8 second range and top speed over 80 mph in all electric mode.
        • 6 Years Ago
        Gas mileage when the generator is on will be somewhere between 40-50 mpg. Since the engine is only powering the battery for the drive, they will be able to keep the engine running at its sweet spot (peak efficiency) --- which will make the big difference.

        tankd0g:
        It's top speed will be around 100 mph. That speed can be reach in either mode. The reason is that this is a serial system (not parallel like the Prius). So the electric motor is always running the wheels, regardless of mode. The only difference is whether the generator is recharging the battery or not.
        • 6 Years Ago
        tankdog:
        The motor driving the wheels is about 150kW peak. That's over 200HP. You don't think a car this size can merge well with "only" 200HP?

        There's no need to make up incorrect info.
        • 6 Years Ago
        tankd0g:
        I am a lot smarter than that.

        The reason it can expend 200HP for short period is because it has batteries in it. These can provide more power for short periods than the continuous output of the generator.

        Look at it this way, a Tesla Roadster doesn't have a generator at all. By your argument it couldn't possibly expend more than 0HP in acceleration.

        Because as I mentioned above, unless you are going steeply uphill on an incline that never ends or pulling a trailer you cannot use more than 75HP in continuous level operation (even at the speed limiter), the generator does not have to be as large as the motor is.

        So when you do get to 30%, the performance may be limited at times. It isn't as a rule, because the battery can dip below 30% for short periods in order to accelerate on onramps and such. But if you were towing a trailer or climbing a hill, your top speed would be further limited to keep the power usage down to where the battery is not endangered.

        A series hybrid is definitely less efficient than a parallel one.. As such, I feel Toyota was very wise to make the Prius a parallel hybrid. However, once you make a plug-in, the overall efficiency increase of a vehicle with a non-trivial zero emissions range in normal use (where you plug it in and do a significant portion of your driving under electric power only) can be higher than that of a parallel hybrid. So I think given Toyota has the parallel hybrid pretty much nailed, it is smart of GM to try to strike out to new ground. Yes, it's a risk, but I think it's a smart risk.
        • 6 Years Ago
        tankd0g:

        1st, for the love of god proofread what you're typing. It'll give you a bit of credibility.

        2nd, the volts battery pack is only discharged to roughly 30% before the range extender kicks in. The fact the motor under the hood only puts out 53kW is irrelevant when talking about how much power the electric motor actually driving the wheels can put out. GM would have to royally screw up for the Volt to discharge far enough to not be able to effectively merge into highway traffic using the full potential of the electric motor.
        • 6 Years Ago
        Tom: incorrect, the EPA rating, if GM gets it's way, will be 100mpg based on a combination of using all the battery power and then range extender.
        • 6 Years Ago
        LS1: think about what you just said. A 53kw motor (71hp) that sends it's power through an extra efficiency sucking step in a car the size of a cobalt, hauling around at least 1000 pounds of extra weight. Ya it's going to be a real joy to merge on the freeway.
        • 6 Years Ago
        Wow tankd0g,

        I don't think you have any idea what the hell you're talking about.
        • 6 Years Ago
        There is no "lying" required. The Volt battery is supposedly rated at 16kWh (according to wikipedia and it's linked sources). The wikipedia page also states the usable charge is between 30% and 85%, which is typical of LiON batteries (overcharging makes them go boom and discharging to an unrecoverable low voltage). Questioning the need for a tow-truck at 25% shows you're either trolling because it's a GM product or don't understand the system (batteries are such a magical thing you know). If you discharge the pack to 30%, you're left with 4.8kWh (16kWh*.3, hard math), enough to run the 150kW motor at 100% output for almost 2 minutes (4.8kWh/150kW = .032 hour = 1.92 minutes, again, hard math), which isn't going to happen in real world driving conditions outside intentional abuse if the computer will even let you. That also doesn't account for the power the generator is putting back into the system or you killing your battery in the process.

        GM's claims have a hell of a lot more weight behind them than you posting here claiming to be an engineer (I can do that too even though my concentration is structural ;) ). GM has multiple tangible working examples on the road while we're here arguing whether or not the EEs GM has on staff know what they're doing. As I've said before in other threads, people here like to shoot from the hip with back-of-the-napkin calculations (Yes, I'm guilty of it too). If you're so sure GM is lying about the range, crunch the numbers, post them and prove your point. You're an engineer, you can do the math.

        If you don't like the Volt, cool, go buy something else. The rest of us would like to see something new for a change though, even if GM fails to get there or dies in the process.
        • 6 Years Ago
        I'll be very surprised if it can even achieve freeway speed in that mode, let alone get decent millage.
        • 6 Years Ago
        RyanK: You're theoretical situation reads right out of the Volt press releases. If the battery is only going to discharge down to 30% then either GM is lying about the battery only range or the battery is going to be bigger than claimed. Furthermore, are you going to be blocked from using that 30%? Is it tow truck time when you get to 25%? How is that extra bit left in the battery going to be of any help you you merging in gas motor only mode if you can't use it for fear of damaging the battery? This serial hybrid idea is not new, it predates the Prius design, Toyota abandoned it for the very reasons GM is having problems now. The range extended Rav4 EVs got worse gas millage than their ICE powered counterparts with terrible performance.

        I can not believe how many people can not see these conflicting claims for what they are. I'm an engineer but this is high school physics level stuff we're talking about here (well, Canadian high school physics). The level of fanboy-ism is laughable. The company is BANKRUPT, and you want to be first in line to buy an experimental $40,000 car from them that they have yet to get to work as advertised but plan to rush into production in a year's time?

        Good luck with that.
        • 6 Years Ago
        The average modern gasoline car needs about 20bhp to maintain 60mph. The number will vary due to gearing, drag, weight, ect.

        My 1990 Geo Metro could do 85mph with 52bhp.

        Still think 53kW or 75bhp is not enough? The RAV4 EV only needed 326Wh/mile. And that was mini SUV from 2001. The previous generation Prius managed 250Wh/mile.
      • 6 Years Ago
      I didn't know you could drive Vaporware until now.



      This comment is for the poster who earlier today still insisted that the Volt is vaporware. Good to see GM progressing along nicely and hope they surprise all the detractors by releasing it on it's scheduled time.
        • 6 Years Ago
        Tagg, 3 years ago I was reading articles about how GM was in great shape and projected to be back on top by now. Don't trust press releases.
        • 6 Years Ago
        tankdog - I think you're an idiot. Now I wanna see the EV test-mule you make by 8am tommorrow morning.
        • 6 Years Ago
        Take another sip of kool-aid. this was a publicity stunt to keep Obama off their back, nothing more. Any idiot could take an off the shelf EV drivetrain and make a Cruze into an EV capable of placating some jounos for an hour.
        • 6 Years Ago
        You'll have to go to my university and see if they still have it. The one we build in 1998.
        • 6 Years Ago
        You're right Tankdog, it is a publicity stunt but it's very good and a needed one at that. With all the dire talk surrounding GM this is a great idea to show the general public that GM is capable of making cutting edge product.

        If you read the friggn' article and you would learn that the mules have been testing for over a year. So if some "idiot" pulled it off the shelf and stuffed in a Cruze to placate some journos then they took off GM's shelf. This is a unique drivetrain the they developed from the ground up. Get over it.
      • 6 Years Ago
      I was about to say... nice car, shame about the negativity.
      • 6 Years Ago
      The Volt's technology is very interesting--and the Cruze this mule is based on is quite a looker, too.
      • 6 Years Ago
      awesome
      • 6 Years Ago
      So much negativity here.
        • 6 Years Ago
        No, there's just a lot of people invested in oil. And some more people who take advice on what to think from people invested in oil.
      • 6 Years Ago
      "...some of the warning lights remained lit throughout our drive."

      Just like my Cavalier. Someone had to say it :)
        • 6 Years Ago
        No one really had to say it.
        • 6 Years Ago
        "Someone had to say it :)"

        I beg to differ.
        • 6 Years Ago
        I had an '89 Grand Am that had a "check engine" light that never turned off. I assume it was a glitch with the early OBD computer, because in over 180,000 mi., there was never a problem with the engine itself, except for that week that I tried some high-power spark plugs.

        Loved that car, sniff.
      • 6 Years Ago
      Anybody notice that Fiat 500 in the background of one of the pics?
        • 6 Years Ago
        it's not a 500...is it? It's hard to make out...but all I see are GM vehicles doesn't make sense to have 500...
      • 6 Years Ago
      Get your facts here:

      http://gm-volt.com/
      • 6 Years Ago
      The head and tail lights of this Cruse are looking so made in China!

      head lights resemble new accord ones.
      tail lights - new sebring

      • 6 Years Ago
      LG Batteries? Oh, they're made by a South Korean company. Yep. The car that will save America (GM) is powered by Korean batteries. Hilarious.
        • 6 Years Ago
        my thoughts exactly...idk just doesnt make sense. Imagine a US company that builds these batteries for all the volt variations across the globe...now that we be some economical contribution
        • 6 Years Ago
        Even Lutz said this car isn't going to save GM. But he did say it's the car GM *should* be building.

        If you think Korean products are bad, look at Samsung or Hyundai and reconsider your idiotic statement.
        • 6 Years Ago
        LG Chem announced last week that it would be building a factory in Michigan to produce lithium ion cells for automotive customers.
        • 6 Years Ago
        @ Tagline: Uh, no I haven't. Ever. I love Hyundai.... I have a hatred for GM and it's stupid decisions, but I'm a huge genesis fan. I don't know what you are smoking, but you're not describing me.
        • 6 Years Ago
        tagg: Point taken, but Rob has been known to hate Korean products in the past, and frankly, it's a little annoying. My own personal beef. ;)

        for the last time, it's taglane. with an a.
      • 6 Years Ago
      The GM Volt business case is BUST!

      No way the Volt will sell at $40K when you get buy many hybrids for $20-$30k that have a much longer range (Fusion Hybrid just drive 1,445 miles on one tank gas!).

      Chinese BYD is building an electric car like the Volt concept for less than $20K.

      Ford has partnered with 3rd party vendor (Magna) to build electric drivetrain thats portable across various platforms at near $0 cost (and risk) to Ford.

      Building Volt on a seperate platform was Stupid and too expensive - look at Toyota Prius still does not make money. The Caddy electric car off the Volt is a 2-door - coupes do NOT sell in sufficient numbers = Stupid!
        • 6 Years Ago
        The Fusion figures are misleading. You can hypermile an Accord to about 100mpg.

        The BYD FD3M is a bust-out. It appears the company was full of crap.

        http://www.autobloggreen.com/2009/04/13/chinese-plug-in-hybrid-byd-f3dm-has-sold-just-80-copies-in-fou/

        I dunno about the Ford thing.

        The Volt is not the only vehicle on its platform. The Cruze is on the same platform. The Prius makes money for Toyota. Do you think Honda decided to compete against it because they wanted to join in the money losing too?

        With the right amount of wrong info, you can make any argument. You're doing a great job of it.
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