Notable German automakers BMW, Mercedes-Benz, and Porsche all showed off hybrid vehicles at the 2009 Frankfurt auto show, demonstrating an interest in making their big, luxury cars more efficient.
BMW Vision EfficientDynamics
With its emphasis on uncompromising sports car performance, BMW hasn't exactly been on the cutting edge of fuel efficient design. But the Vision EfficientDynamics concept shows that the company is taking a hard look at how it can improve efficiency. The concept uses an aerodynamic design and a complex hybrid power train to get 63 mpg, without sacrificing sports car performance.
The odd-looking exterior is designed for aerodynamic efficiency, ducting air over the car to achieve a drag coefficient of 0.22, better than the Prius' 0.25. As the concept sits low, BMW gave it gullwing doors to allow easy access to the cabin.
BMW included this exposed power train in its display for the Vision EfficientDynamics. It shows the 1.5-liter three-cylinder diesel engine combined with an electric motor on the rear axle, and the two electric motors on the front axle. This power train gives the car 356 horsepower and 590 pound-feet of torque, getting it to 62 mph in 4.8 seconds.
Volkswagen has been working on the idea of a car that can go 100 kilometers on 1 liter of fuel since 2002. The latest result of this research is this hybrid L1, although it doesn't quite live up to the goal, using 1.38 liters of diesel to go 100 kilometers. Still, that's the equivalent of 170 mpg.
Narrower than a typical car, the L1 still sits on four wheels. Its power train is composed of a 0.8-liter two-cylinder diesel engine and an electric motor integrated with the seven-speed Direct Shift Gearbox. With its 10-liter fuel tank, Volkswagen estimates a range of 416 miles.
With the popularity of compact luxury cars in Europe, Lexus introduces the LF-Ch as a hybrid to compete in that market. A four-door hatchback design, the LF-Ch would compete closely with the BMW 1-series hatchback.
Lexus doesn't specify the hybrid power train for the LF-Ch concept, but it would most likely be similar to that used in the Toyota Prius or the Lexus HS 250h. Lexus does say that the hybrid system would reduce NOx emissions, suggesting that a diesel electric hybrid is under consideration.
The lack of outlandish concept touches in the cabin suggest that Lexus is seriously considering a production model. The car uses the same touch controller for the infotainment system as the Lexus RX 450h. Paddles on the steering wheel let the driver shift virtual gears.
The Active Hybrid 7 is a mild hybrid, meaning its electric motor can't drive the car by itself. The hybrid system in this car adds some efficiency, such as idle-stop capabilities, but only gives it an overall fuel economy of 24 mpg.
The Active Hybrid 7 doesn't lack for power, featuring a twin-turbo V-8. With its hybrid system, the total power output is 465 horsepower and 516 pound-feet of torque, getting it to 62 mph in 4.9 seconds.
Mercedes-Benz is currently in the process of launching its S400 Hybrid, an S-class with a mild hybrid system. The S500 Plug-in Hybrid concept uses a full-hybrid system that can drive the car under electric power for almost 20 miles. The efficiencies of its hybrid system give it an average fuel economy of 74 mpg.
The S500 uses a 3-liter direct injection V-6 gasoline engine coupled to a 44-kilowatt electric motor. Acceleration to 62 mph is estimated at 5.5 seconds. As the S500 also has plug-in capabilities, the lithium ion battery pack can be recharged in 60 minutes from a rapid recharger.
The hybrid power train is mated to a seven-speed automatic transmission, similar to that found in current Mercedes-Benz cars. And like the current S-class, an LCD on the instrument cluster shows a virtual speedometer, but is also used to show hybrid system information.
The Cayenne Hybrid comes out next year, sporting a supercharged 3-liter V-6 assisted by a 38-kilowatt electric motor, making for a combined output of 374 horsepower. Porsche's hybrid technology is fairly standard, using a nickel-metal-hydride battery pack. But the power is routed through an eight-speed automatic transmission.
BMW partnered with GM and Daimler to develop the two-mode hybrid system, and the Active Hybrid X6 is BMW's first application of the technology. Instead of decreasing the X6's engine size, BMW merely adds the hybrid system to it, making for an overall increase in power and fuel economy of 24 mpg.
The power train is composed of a twin turbo V-8 gasoline engine complemented by two electric motors of 67 kilowatts and 63 kilowatts powering all four wheels. The total power output is rated at 485 horsepower and 575 pound-feet of torque, with acceleration to 62 mph in 5.6 seconds.
The hybrid system can power the Active Hybrid X6 under electric power alone at speeds up to 37 mph, and regenerative braking feeds electricity back into the nickel-metal-hydride battery pack. Besides some hybrid information in the instrument cluster, the interior is similar to that of the standard X6.