Last Updated Oct 12, 2010 5:39 PM EDT
According to a couple of early press reviews, the Chevy Volt didn't get anything close to that awesome mileage in real-world driving. Popular Mechanics, for instance, found that the Chevy Volt got around 38 mpg. That's good, but it's easily achievable by mere mortal cars equipped with ordinary gasoline or diesel engines. That's a lot more relevant to consumers than technical details most people don't know or really care about.
GM has an out, of sorts. The Chevy Volt carries a giant asterisk that says, "Actual Mileage May Vary." Apparently, GM's PR machine got GM engineers to sign off on that 230-mpg figure, but it must have achieved under ideal conditions. The EPA hasn't yet assigned a mileage estimate; that'll be interesting to see.
A key advantage for the Chevy Volt is that it goes a lot farther on battery power alone than today's hybrid cars. The battery power runs out after about 40 miles, versus only a couple of miles for most hybrids today.
The technical argument behind the current PR flap is whether the Chevy Volt should be classified as an Extended Range Electric Vehicle, as GM insists, or whether it should be classified as a slightly less-exotic plug-in hybrid.
GM says the distinction is that an EREV is always driven by electricity. The electricity comes either from plugging the car in and recharging it from an outlet, or else from the onboard gasoline motor acting as a generator.
GM now allows that under certain circumstances, the gasoline engine in the Chevy Volt does "indirectly" help move the car down the road at highway speeds when the battery is depleted. GM says the final version of the system is more fuel-efficient than if the system didn't use any power from the gasoline engine.
I doubt many consumers are going to care if once in a while the gas engine helps drive the car. For those few who do, if the Chevy Volt can back up its extremely high mileage claims, I think all will be forgiven.