Audi 80 Fox
The new merged company was known as Audi NSU Auto Union AG, and saw the emergence of Audi as a separate brand for the first time since the pre-war era. Volkswagen introduced the Audi brand to the United States for the 1970 model year.
The first new car of this regime was the Audi 100 of 1968. This was soon joined by the Audi 80/Fox (which formed the basis for the 1973 Volkswagen Passat) in 1972 and the Audi 50 (later rebadged as the Volkswagen Polo) in 1974. The Audi 50 was a seminal design because it was the first incarnation of the Golf/Polo concept, one that led to a hugely successful world car.
Source: Wikipedia, 2013