To this day, Audi remains the first European manufacturer to have series-manufactured a hybrid vehicle, an honour it has held since 1997 when it brought out the Audi duo based on the A4 Avant. Drive power was provided by a 1.9-litre TDI engine developing 90 bhp assisted by an electric motor with a further 29 bhp. Both delivered their joint drive power to the front wheels, with a lead-gel battery at the rear of the vehicle providing the necessary electrical energy.

The first ever generation of the Audi duo was actually unveiled as early as 1989, however. The experimental vehicle built on the platform of an Audi 100 Avant quattro was equipped with a 12.6-bhp electric motor which was responsible for driving the rear wheels instead of the propeller shaft. Energy was sourced from a nickel-cadmium battery. A 2.3-litre five-cylinder engine delivering 136 bhp powered the front wheels.

Just two years later, Audi developers revealed the second generation of the duo, likewise in the guise of an Audi 100 Avant quattro. The electric motor, a 28.6-bhp AC unit, once again propelled the rear wheels. This time however, a Torsen differential was included to route extra power to the rear wheels from the two-litre four-cylinder engine up front.

Throughout the many years of development, Audi engineers have carried out pioneering work that has played a key role in the advancement of hybrid technology up to full production maturity. This applies both to overall concept development and to more specialist areas, such as their work on sophisticated battery technology as well as on the highly advanced energy management system that is now at the heart of the Audi Q7 hybrid.

The equipment, data and prices stated here refer to the model range offered for sale in Germany. Subject to amendment; errors and omissions excepted.