I may have answered my own question. I found an article on "e coating" from a company called PCI.
E coat stands for the electrolosis process... not the type of paint. The process had been around since before epoxies. I think it was the thirties or forties.
It says that today they are using mostly epoxy or acrylic paints in the e coat process, depending on the climate and area that the products will be used.
Sounds like the car manufacturers use mostly epoxy.