FRANKFURT •  There weren't a lot of concept vehicles at the Frankfurt Motor Show, as most of the unveilings were production versions, but those that did qualify as prototypes did not disappoint. Following are some of the highlights from the show floor:

Audi
People started gathering early at the Audi stand and waited even longer as the automaker's presentation was delayed by 15 minutes. But it was well worth the wait. Audi took the wraps off its new e-tron plug-in electric sports car concept, a 313-horsepower two-seater that Audi says will go from zero to 100 kilometres an hour in a mere 4.8 seconds.
The e-tron is powered by a pure electric drive system, with a lithium-ion battery that provides 42.4 kilowatt hours for a range of close to 250 km. It features four individual electric motors (two in the front and two in the rear axles).
The e-tron can be plugged in to any household 230-volt outlet. With the battery fully charged, the charging time is between six and eight hours, Audi says. A high-voltage outlet (400 volts) reduces the charging time to about 2.5 hours. Audi  says it is working on a wireless version to make charging more convenient.
The battery is charged when the car is in motion as well as when it's stationary. Audi has also introduced a heat pump to increase the e-tron's efficiency and range.