Mercedes-Benz is planning a suit against Audi for infringement of its Bluetec technology. Under a European patent Daimler owns rights to the particular nature of the system, which controls emissions of diesel engines.

Daimler claims to have sent at least three letters through its legal department to Audi engine chief Wolfgang Hatz requesting the company's response on the matter. Mercedes felt Audi's response was inadequate and decided to move forward with a patent claim against its compatriot company, according to our German colleagues at Auto Motor und Sport.

The systems Mercedes is citing as violating its patented system include the emissions systems on the upcoming A4 and Q7 diesels. Some have taken note of the timing at issue - namely, Audi's clean diesel models are scheduled to enter the European market several months before Mercedes upcoming Bluetec models.

At most, if Daimler and Mercedes-Benz prevail in their claim, they might win some damages and prohibit Audi from distributing systems equipped with infringing systems without paying a license fee. At worst, it will be an endless money-pit of litigation and mud-slinging. Only time will tell, and at the rate things move in the legal and automotive industries, it will likely be quite a lot of time.