Hybrid vehicles are changing the way drivers think about performance. Horsepower and torque numbers still play a role, but gone are the days of bigger is always better. Instead, drivers have to look to how power systems are paired and how they work together.
The power plant of the Fisker's Q Drive system -- a Quantum Technologies plug-in hybrid system that was specifically developed for Fisker Automotive -- is two 201-horsepower electric motors working through the car's rear differential. These motors draw their power from a manganese-based lithium-ion battery pack producing an open circuit voltage of about 400 volts. The Karma's charging strategy includes an on-board generator hooked to a 260-horsepower, 2.0-liter, four-cylinder, turbocharged, direct injection Ecotec engine. The Ecotec engine is produced by General Motors and used by several car companies.
All these elements tie into two broad concepts -- efficiency and performance.
Global statistics indicate pollution from cars is highest during short commutes and typical around-town errands. In addition, most Americans and Europeans -- about 60 percent -- drive their cars fewer than 50 miles per day. For almost all cars, the engine and emissions control system needs to be at a specific operating temperature to function at its peak effectiveness. During a short drive, like in the case of local errands and most daily commute driving, the engines simply don't reach that critical operating temperature.
However, the Karma's battery pack will operate the vehicle for a range of about 50 miles (80.5 kilometers) under ideal conditions -- remember, speed, terrain and driving style all play a role in depleting battery power to a greater or lesser degree -- meaning no emissions for those miles. The batteries have an estimated life of 10 to 12 years, and the charging cost is relatively small. Fisker spokesman Russell Datz estimated charging the batteries in the Fisker Karma would cost the gas equivalent of about 25 cents per gallon.
As the battery runs down, the system will kick-in the engine to drive the generator and provide additional power to the electric motors. According to Fisker, this proprietary system will be used in all future models and products. But what does all this mean for the driver? Continue reading to find out.