• Oct 11th 2010 at 10:00AM
  • 264
On the first day of its Chevy Volt media drive program, GM officials confirmed speculation that the Volt's 1.4-liter gas engine does help drive the wheels of the car, "in low torque situations," according to Volt chief engineer Andrew Farah. "It's all about efficiency," he said. GM is using a version of its two-mode hybrid transmission that allows for a so-called "power split" mode that connects the crankshaft of the gas engine to the Volt's two electric drive motors by means of a planetary gearset. This allows the power from the gas engine to be blended with the power from both electric drive motors, primarily during high-speed operation, where GM says this mode provides 10-15 percent better fuel economy.

Leaf The Volt transaxle is more complex than many media and onlookers had been led to believe. It employs two electric motors, a planetary gear set, and three clutches, and can operate in four distinct drive modes, switching between them as conditions warrant.

The first mode is the easiest to understand, as it uses the 111 kw traction motors to drive the wheels, with all the electric power coming from the battery. This EV mode delivers 273 lb-ft of torque to the wheels and makes the Volt fairly quick to accelerate from a standing start.

The second EV mode employs both electric motors -- the traction motor and the 55 kw generator – to drive the wheels, with electric power coming from the battery. This mode blends the power by means of the planetary gearset to allow for improved highway efficiency, as both motors are able to run closer to their optimal efficiency.

The third mode happens during extended range driving, when the gasoline engine is operating. In this mode the traction motor drives the wheels, with electricity coming from the battery as well as the motor generator, which is being spun by the gas engine. GM calls this a "weak series" arrangement, as the battery is always the lead power source.
Did GM lie about the Volt?
Yes, it's not a pure EV if the engine can power the wheels. 1494 (39.3%)
No, it's still fundamentally an electric vehicle. 524 (13.8%)
I don't care as long as GM engineers used the most efficient design. 1779 (46.9%)

It's the final mode that's come as a bit of a surprise, because it is in this extended range mode where both electric motors and the gasoline engine get connected to drive the wheels. However, GM is still maintaining its stance that there is "no direct mechanical linkage from the engine to the wheels," while explaining that "the Volt is always propelled with electric power delivered by the traction motor."

While there is still likely a semantic argument to be waged here -- whether we call it a plug-in hybrid or an extended-range electric vehicle is a discussion for another day -- the bottom line is that the Volt employs a sophisticated transmission to eke out every efficiency from its drive system.

Watch Bradley take the 2011 Chevy Volt for a spin at GM's secret proving grounds.

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    • 1 Second Ago
      • 4 Years Ago
      toni jo

      the only way gas will get to $6-$8/gal will be at the hands of the SOCIALIST GOVERNMENT that is trying to sell human created global warming! Oh! i should have included the environmental nazis in that, but
      then again, they are probably incestuously married, anyway. The sad part of it all is that "green cars" are the cause of greater pollution
      than traditional fossil fuel cars. It's basic physics. When you use
      fossil fuel (gasoline) to power an electric generator to charge a battery or drive an electric motor, and/or use the electrical power
      grid to charge that same battery, there is a net loss to the energy system relative to the energy expended when that same fuel directly
      powers the car (as in a gasoline engine driven vehicle). I takes MORE
      fossil fuel to go that 40 mile trip in that "green car" than in a reasonably efficient traditional car. It also adds the enviromentally disasterous problem of battery disposal (don't you just love all those heavy metals and acids?). But, hey, there's always solar and wind as
      clean electricity sources, right? Ever hear of "energy density" ?
      If not, it may be because solar and wind "power" don't have much!
      Wind don't always blow; sun don't always shine, and even if they did,
      consider this: the energy of one gallon of gasoline is the result of
      millions of years of storage and accumulation of solar energy. How does
      this compare to the few minutes (or even hours) of solar radiation col-
      lected by even the hugest solar panel array? And wind is only the mechanical expression of solar energy. It just ain't there,folks!
      The GREEN movement is at best, misguided. But the size and institutionalized nature of its support would indicate otherwise.
      "Why?", you might ask? In pursuit of the nearest, easaiest buck (as in
      $$$), those in power and those that want to be in power follow the sage philosophies of socialism (give 'em what they want,free and then smack 'em in the mouth with the bill) and P.T.Barnum (there's a sucker born every minute).

      • 8 Months Ago
      Scott...Wake up and smell the coffee.....Gm simply moved money around they received from the taxpayers!!!! They stiffed all their Bondholders out of Billions...Their stock became worthless to investors....They laid off 50,000 workers and closed 1500 deallerships . Then the government gives them 50 Billion to start anew with no debts!!!! Some success story!!!!!!!!!!!!
      • 8 Months Ago
      The last time I was in Europe, the rented car gave me 580 miles per gas tank and was willing and ready to go over 100 Mph any time. So what is so great about the new GM hype? The hype itself.
      • 4 Years Ago
      I was under the impression that this was going to be an electric car. It isn't. It's a gas-powered car with electricity as the secondary. Why did they even bother? It still has emissions and the goal I thought was to begin to build emissions-free vehicles running solely on electric and work on extending the range. If this is the future trend they might as well stick with gas engines and discontinue electric altogether. I vote for the Nissan Leaf and I wouldn't buy one of these Volts.
      • 4 Years Ago
      There is no battery magic folks. Headlights, a/c, heater, wipers all take energy too. What works in sunny SoCal needs to work in Green Bay or Syracuse as well. There's no battery technology today or on the horizon that'll get us to a practical (a.k.a marketable) 200Km vehicle (day/night/all-weather)at a reasonable cost. The Volt is a valuable step toward an EV and the compromises are needed for this to be a step forward and not a slip'n'fall market disaster.
      • 8 Months Ago
      don't see to many on the road,guess it may be the high price tag ,also the fuel stations need to be upgraded to charge these vehicles haven't seen that either...
      • 8 Months Ago
      • 8 Months Ago
      Rear engine Chevette, or are you thinking of Corvair?
      • 8 Months Ago
      250,000 tax payer dollars wasted...check.....coal burning, gas burning so called ev....check.....spontaneus combustion do to the overheating cell phone batterys they throw in it.....check.....the smiles on obama and his cronies faces laughing all the way to the bank at us stupid americans.... priceless
        • 8 Months Ago
        did you kmow the same amount of coal is burned no matter what the power output needed try listening to the people who own one not the bs you here on fox.
      • 8 Months Ago
      Good luck, I hope they can make the cost / price as efficient their creative drivetrain.
      • 4 Years Ago
      The article says it over and over: complex drive train. That means one and only one thing to me: The d**** thing is going to break...repeatedly...and it'll be EXPENSIVE to repair it. 1/2 the point of an electric vehicle is reliability. So much for that. Still looking for a main stream electric.
      • 4 Years Ago
      support the people that are paying the bills, buy a honda. Good milage cheap price, and if china goes under, who's going to bail us out.
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