There are too many makers that fit your vague hint ("There have been more characteristic cars by this manufacturer"), such as Rumpler, Mauser and so on and my idea was to narrow down my huge list.
The geographic way will be more or less as "unprofessional" as the alphabetic one and the 3 books I browsed confirmed that this car has nothing expecial but the slightly round radiator to make it different from any Falcon, Ego, etc I considered.
I think I'll save some time waiting other puzzlers to find out what is the correct line of questions you like more and follow that path.
Since I don't want to waste a reply, here's an educated guess: Omega 3/10 PS?