Who owns the TDI acronym? At least it isn't Audi

The acronym TDI means a great deal in the automotive world, indicating that we are dealing with a diesel car with a turbo and direct injection. It seems that Fiat was the first company to put a model equipped with TDI on the market (the Fiat Croma), although these days Volkswagen, Mercedes and Audi have all turned the three letters into a genuine registered trademark.

Audi, through the Volkswagen Group, believed that TDI could become one of its registered trademarks and did not hesitate to turn to the Court of Justice of the European Union in an attempt to register the acronym TDI under its name. That court rejected the request, stating that TDI designates an engine technology that is offered not only by Audi but also by other brands, and that it is not a name or a brand but an acronym that does not deserve protection or registration.

It seems that Audi holds the TDI name registered in certain countries, which gives it the right to prevent any other brand from using that name for a diesel or any other engine configuration or model.