Reports in Motor Trend, Popular Mechanics and on Edmunds.com assert that the Volt relies on its gasoline engine to power an electric generator that helps turn the wheels under heavy acceleration, not unlike the way in which hybrid vehicles, such as Toyota Motor's (TM) Prius, are powered.
In a posting Monday, Edmunds.com was scathing in its attack on GM, saying the Detroit automaker has "lied" because the Volt isn't a true extended-range vehicle that relies solely on its electric engine for locomotion. From the review:
GM has said the Volt, which features both electric and gasoline engines, relies solely on electricity to power its wheels, using the internal combustion engine merely as a backup to generate electricity when driving long distances. Popular Mechanics took aim at GM's eyebrow-raising claim that the Volt was capable of achieving the equivalent of 230 mpg.
- Despite promises that the Chevy Volt will operate as an electric car at all times, it will in fact at times be directly driven in part by its internal combustion engine.
- The mechanical link between Ecotec internal combustion engine and drive wheels will be at high speed.
In three separate, distinct driving tests, equivalent mpg ranged from about 32 mpg to about 36 mpg in extended-range mode, when its gasoline engine kicks in. Still, the magazine called the Volt a "well-engineered first step on the path to electrified vehicles." In its tests, Motor Trend said it achieved mpg in the "high 30s to low 40s."
In response, GM said on its media website it wanted to clarify points in the wake of inaccurate media reports:
However, despite its assertions that the Volt is a true electric vehicle, it could do better in defending its claim. Using phrases such as "there is no direct mechanical connection" seems more like parsing than explaining.
- The Volt has an innovative electric drive system that can deliver power in both pure electric and extended range driving. The Voltec electric drive cannot operate without power from the electric motors. If the traction motor is disabled, the range-extending internal combustion engine cannot drive the vehicle by itself.
- There is no direct mechanical connection (fixed gear ratio) between the Volt's extended-range 1.4 liter engine and the drive wheels. In extended-range driving, the engine generates power that is fed through the drive unit and is balanced by the generator and traction motor. The resulting power flow provides a 10% to 15% improvement in highway fuel economy.
- Our overriding objective in developing the Voltec electric drive was to deliver the most efficient, yet fun-to-drive experience in both pure electric and extended-range driving. We think our unique technology lives up to its most important promise: delivering our customers with the only [electric vehicle] that can be their primary vehicle, with EV operation for normal daily driving, and extended range driving for weekends, holidays and longer trips -- all with no range anxiety.
With GM seeking not only to reengage American consumers but investors on Wall Street, too, ahead of its planned IPO next month, the auto giant could do better in simply explaining its claims -- and steer clear of the old GM's tendency in reacting to criticism rather than preventing it.