Quote:
Originally Posted by Perian
Link:  http://www.edmunds.com/insideline/do...ticleId=132112
DETROIT — Remember when we wrote that the 2011 Chevrolet Volt would be able to run 40 miles on pure electric power and then fire up an onboard four-cylinder engine to recharge the batteries?
Turns out, that's not at all true.
In contrast to popular (and our) impression, once a driver uses up his 40 or so miles of electric power, the 1.4-liter gas engine generates electricity to power the electric drive motor, but does not recharge the batteries. After the 40 or so miles, the battery becomes 400 pounds of uselessness, at least until the owner can plug the car into the electrical grid for a recharge. This means that regardless of how far one drives the Volt, the driver will only ever get up to 40 miles of electric-only range.
Our confusion and that of much of the media corps might have to do with the fact that the company once wrote this: "When the battery is depleted, a 1-liter, three-cylinder turbocharged engine spins at a constant speed, or revolutions per minute (rpm), to create electricity and replenish the battery."
That was from a press release written for the 2007 Detroit Auto Show, where the Volt concept was unveiled. A release from the day of the production prototype's reveal reads, "a gasoline/E85-powered engine generator seamlessly provides electricity to power the Volt's electric drive unit while simultaneously sustaining the charge of the battery." And by "sustaining" GM says that it means only that no additional power is drained from the batteries. Get it? |
Sorry, but no I don't. It may be true that the engine never charges the battery, but therefore the battery is not "sustained" after 40 miles, either.
We know the engine can't get it done alone, or we'd not be hearing about a finite 600 or so mile total range. Meaning, once the 40 miles of battery-only propulsion is done, the engine and the battery are working together. If the engine were sufficient to propel the car and "sustain" a constant battery charge from 40 miles onward, then the car wouldn't have any 600 mile limit -- it'd be like the energizer bunny, going and going so long as fuel's in the tank. Therefore, I think this guy's missing the point. The battery must indeed lose charge after 40 miles. The remaining charge after 40 miles is enough so that, when accompanied by the engine's power generation, the car goes about 600 miles. When the battery is done, so is the trip.
One would think that the batteries are indeed getting charge from the engine after 40 miles... Because at times the electricity needed for propulsion will be less than what the engine can deliver, so the battery becomes a reservoir. And regenerative braking would have to add juice to the battery otherwise be lost. But that may be the news ... that the engine never adds anything to the battery and there are no supplemental regenerative systems. The engine and battery power are isolated. In which case, the engine will never add electric-only range to the car. It's 40 miles and no more. Even if you park the car after 40 miles with the engine on, the system may not be programmed or even wired to restore the battery for any additional electric-only range.
And here's where I'll make an educated guess ... the reason they'd do it that way is to extend the life of the battery, which is already the weakest reliability link on the car.