CITRON The Citroen logo looks like something you might see on an American cartoon soldier - two inverted Vs. Andre Citroen - imagine one of those old black and white photographs with an ancient man in a white beard - started in the motor trade by building gear wheels before branching out into the motorcar, and the twin chevrons << are meant to represent gear teeth in honour of the old engineer's early fettlings

The company's famous "double chevron" logo derives from André Citroën's early business in gear-cutting the company pioneered mass production of double helically-cut gear teeth, which mesh together in a chevron.

BMW
BMW stands for Bayerische Motoren Werke or Bavarian Motor Company. The company was established in 1913 and based in Munich, Germany. It started out as an aero engine manufacturer, hence the company logo. The logo comprised of four quadrants of alternating white and blue color. It is a stylized representation of an airplane propeller spinning against the clear blue sky. The logo represents a white propeller blade against a blue sky. It reflects the origins of BMW as a maker of military aircraft engines during WWI. Also, white and blue are the traditional colors of Bavaria.
Audi
The Audi badge the 'Four Rings' is the emblem of one of the oldest car manufacturers in Germany. It symbolises the 1932 merger of the four independent motor-vehicle manufacturers: Audi, DKW, Horch and Wanderer. Together with the NSU brand, which joined in 1969, these companies are the roots of the present-day AUDI AG. After the war the Audi name - which is Latin for "Hear!" - disappeared, but was revived in 1965, using the four rings as a logo. Also, the name is sort of a pun on 'hoerch', German for 'hear', name of one of the founders. The company itself is more than a century old.

The four rings in the logo have nothing to do with the Olympic rings.