Back in July, BMW announced the imminent addition of new diesel models to the U.S. market. At the time the Bavarians only mentioned the engine choices while refraining from placing them into a specific product: a 2.0 liter four-cylinder and 3.0 liter six-cylinder units.

We speculated at the time that most likely the 3 Series family will get both a four and six-cylinder banger, with the possibility of an X model to be powered by a diesel as well. Since then we have learned that not only the 3 Series sedan will get diesels, but also the Sports Wagon model as well.

And today, we have the first photos of a BMW 328d spotted near the BMW plant in Steyr. Historically, the German market were fortunate to receive the 320d, 325d and 330d models, and with the new F30 3 Series, only the middle model is missing at the point. There are indications that the 325d will arrive in Germany with model year 2013.

The 328d prototype spotted features a single tailpipe which is a further indication that a four-cylinder turbo is hidden under the hood. The power output is still a mystery, currently BMW offers 184 bhp and 380 Nm (280 lb ft) of torque, and also a twin-turbo variant of the same displacement but with 204 bhp and 400 Nm (295 lb ft) of torque. The U.S. market will see the TwinPower single turbo engine.

BMW will also introduce a 5 Series diesel (with the optional xDrive) and the highly-efficient, yet powerful 740d. From the X family of vehicles, the next generation X5, due out in 2014, will also be powered by a 3.0 liter diesel; the engine is expected to output 255 hp and 413 lb-ft of torque between 1500-3000 rpm.

The new diesels are rumored to appear in 2013.

[Photos: Patrick for]