Flame wars! The blogosphere got incredibly heated up Monday by the incendiary charge that General Motors “lied” about the Chevrolet Volt when it claimed that the car, which is a mere month away from delivery to customers, runs on electricity all of the time. In fact, it doesn’t — the gas motor partially drives the wheels at speeds above 70 mph.

But the difference is pretty technical. GM should use every trick in its arsenal to get maximum range, fuel-efficiency and reduced emissions from the Volt. Doug Parks, a global electric vehicle executive at GM, swore to me that all of these things are improved because of its previously undisclosed trick of using the gas engine to indirectly drive a secondary ring gear after the battery runs down (at highway patrol speeds only). This sneaky use of mechanical energy allows the main electric drive to rachet back a bit at high speeds, improving efficiency.

GM is guilty of misleading the public about the gas engine never driving the wheels. If, as the company says, the new development was “secret sauce,” a proprietary trade secret awaiting patent approval (until two weeks ago), the company should have just shut up about that particular aspect, or said something ambiguous until the press launch now underway. The company tried to explain the car Monday in a video that you can view here.

Instead of leaving well enough alone, the company said the Volt is an “all-electrically driven vehicle” that has “no direct linkage from the engine, through the drive unit to the wheels.” The key word there is “direct.” There’s not a direct link, but there is an indirect one. And according to Kevin Kelly, manager of EV and hybrid communications, at speeds over 70 mph that indirect link is supplying 70 percent of the car’s power (leaving 30 percent from the electric motor).

“While the engine is running, we found a way to boost range and make the extended-range mode more efficient,” said Parks. “We are actually very proud of our system. If we’d just wanted to cover our you-know-what, we could have lost a few miles of range and never connected indirectly to the gas engine. The most important thing is that the car is better because that system is in place.”

As my colleague Jim Henry points out, customers aren’t likely to care much about this kind of dispute, and they shouldn’t. What matters most is whether the Volt delivers on its environmental promises, and is it, in fact, the no-compromise planet-friendly car it claims to be. I think, for most people, it will deliver that because they’re going to be traveling within the up-to-50-mile range of the battery pack.

Jay Leno agrees with me. In a phone interview, he told me the Volt is “the smart one,” because it’s “an electric car 95 percent of the time. But when you need to go to Vegas or San Francisco, it turns into a regular car. That’s the key.”

Nobody likes to be called a liar, and GM isn’t any too happy about this flap emerging on the eve of its launch. “Frankly, we were lied to,” said Insideline.com. “Don’t believe everything GM says. No matter how many times they say it.”

OK, on the rare occasions when I take my Volt over 70 mph, as I watch for Smokies, I’ll hear a tiny mechanical whirring noise as the secondary ring gear engages. And it will be the sound of GM lying to me. And I’ll get over it.

Now to clear the air, here's a completely gratuitous, all-singing, all dancing Chevrolet Volt video:

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Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

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