The last couple of years development in aircraft engines has been more or less concentrating on diesels. We have seen one off installations to fully developed production lines. A number of companies are active on this market primarily due to major concern of long term availability and the relative high price of AVgas (Europe).
More and more diesel engines will become available for the General Aviation market. As AVgas is becoming a thing of the past we need those new engines and having one global type of fuel makes life easier.
The AE 300 is based on a Mercedes Benz OM640 engine which is a liquid-cooled, in-line four-stroke four cylinder engine with a double overhead camshaft (DOHC). Every cylinder has four valves which are actuated by the cam follower. The direct fuel injection is realised with common rail technique and the engine is turbo-charged.
All engine components are controlled by an electronic control system with integrated single power level design. In this system the propeller pitch change is actuated by a governor which is controlled by the ECU.
This engine is being used by Diamond Aircraft in their DA-40, DA-42 and as AE-330 in the DA-62 type aircraft with a TBO of 1800 or more hours.
There isn't much more detailed information available, what we have is in the pdf below: