Well there were v8 diesel engine being used as far back as 1943 if not older ones also. They have been around but not a lot of people use this layout. Diesel are typically laid out in a inline configuration. The main reason being to reduce vibration.
It is not that new, it was first introduced in 1982 but has since then improved quite much. So to answer your question, the engine is not that new, to be precise, it has 20 years on its back.
The first one was in 1955, it was not made for high mpg, but for speed. It got about 10.3Mpg. But, was very fast! If you are looking for a loud car that it what to get.
