Justa thought but the continental european manufacturers seem to prefer alphanumerics whilst the British (inc. Ford & Vauxhall/Opel (GM) preferred names.
Alphanumerics: BMW, Mercedes, Audi, Peugeot, Renault (changed to names in the 90s), Citroen (changed to names now back to letters), Fiatm SAAB, Volvo
Names: Ford, Austin-Rover, Vauxhall,
Spoilers: VW (continental but use names); Austin (Brit but used a lot of numbers).
Traditionally I thought the american cars had used names?