Engine no more power, first I came after a truck, became less and less, until off.

Hello, I have a 1.9TiD with 150hp Built. 2004 Yesterday I was on the highway speedily. Then I realized that the power went back. At first I went 80km/h, no matter if much or little gas. The gearbox shuts down the gears (automatics) but does not help anything. Then after I left the highway with 30km/h, smoke from the engine compartment and everywhere. Engine went off. Quite a lot of oil was distributed in the engine compartment. Before I had opened the oil cover and an unusual overpressure In German, I was speckled with oil. Now the car with the ADAC is on the way home. One has a tip. The power loss up to only a few km/h possible has already occurred several times, according to my wife. (I unfortunately ignored). In the hope of a favorable rescue of the beautiful car, DKCA15 greets.