(May 24, 2011) BERLIN  — Electric-powered rear and four wheel-drive variants of the Porsche Boxster E roadster sparked interest last week at the Michelin Challenge Bibendum in Berlin.

Porsche was demonstrating its Boxster E prototypes to a wide audience of representatives from politics, industry, trade and research at this global forum for sustainable mobility in the German capital.

Around a sporting circuit, the Porsche showcased the Boxster E sports car concept; exhibiting the combination of innovation, performance and chassis responsiveness that is characteristic of the marque, and follows similar ground-breaking initiatives; the 911 GT3 R Hybrid race car, 918 Spyder super sports car and 918 RSR concept.

The Boxster E prototypes are being used as part of the “Model Region Electro-Mobility Stuttgart” to explore the everyday practicality of all-electric vehicles and how they are used, especially in terms of driving and battery charging. What the researchers at Porsche are looking for is an understanding of the requirements that will shape tomorrow’s products, the future direction of Porsche Intelligent Performance and how to integrate electric vehicles into the infrastructure.

Porsche officials say that thanks to its design as a mid-engine sports car, the Porsche Boxster is the ideal vehicle platform for conducting realistic trials with electric-drive systems. The open-top two-seater car is very light, enabling the new components that are the electric motor, battery and high-voltage technology to be accommodated within the vehicle in a crash-proof way.

Together with the low drag, this reduces driving resistance for optimal range. Also of importance for a Porsche sports car, even one that is electrically-driven, is the high driving dynamics potential, not least as a consequence of the balanced axle-load distribution intrinsic to the mid-engine design.

In four-wheel drive format, the Boxster E is an all-electric vehicle without any additional combustion engine on board. Propulsion is provided by two independent electric motors with constant mesh gearboxes that act on the front and rear axles. The rear drive unit comprising motor and transmission, together with the power electronics for controlling the electric motor is located where the manual transmission and exhaust system are accommodated in the conventional Boxster.

The two electric motors develop a total power output of 241 horsepower and a maximum total torque of 398 pound-feet at a maximum engine speed of approximately 12,000 rpm. That means that the two electric motors in tandem deliver significantly higher drive power than what is available from present day hybrid vehicle electric power units.

The two motors enable the two-seater to sprint to 62 mph in 5.5 seconds from a standing start. Its top speed, limited 124 mph is achieved without any gear change at all — whether automatic or manual. The high power output of the two motors offers a second advantage: it means more recovered power is available because more energy can be recovered during braking. This increases efficiency of the drive unit.

In the case of the two other Boxster E models with rear wheel drive there is no front electric motor, therefore delivering a power output of 200 horsepower. This model can sprint from a standing start to 62 mph in 9.8 seconds, with a top speed of 93 mph.