Let's stay for a moment with the utility vehicles. Partly, they were on their way backwards, to the steam-engines because of the fuel costs and also, because the performance of Diesel engines of up to 110Kw (150 Hp) would only be realised around the end of the 1930s, then however, in gigantic engine compartments with very long in-line eight-cylinders. Thereby, the Diesel engines had undergone a huge development, from the extremely heavy stationary- and marine engines and the locomotive engines to the truck- and after 1936, even motor car engines, the latter however, would be accepted almost exclusively by taxi-drivers, because of their economy.
The unsuitable process of blowing the fuel in with the help of air had, for a long time given way to the fuel injection pump. Bosch precured the patents and improved them distinctly. In this case, also for talented manufacturers, adaptions were necessary, the achievement of which, for a long time remained secret. It was the second great thrust, that this company gave to the engine- and thus, the vehicle development. This is why we ask ourselves, how come did this, much more economic engine, assert itself so hesitantly, even today, in much driven American cars, vans and even off-road vehicles they have not yet been fully accepted.
Around the middle of the second world war, because of the shortage of fuel, instead of Diesel, the trend was, at least in the civilian sector, to the wood-gas generator. One should scrap any nostalgic yearnings one ever had for this device, apart from having to alter the vehicles until they were no longer recognizable as such, it produced only a fraction of the performance and at least once a week an extensive cleansing ritual was necessary. The forest was the filling station!, indeed, one had to take long heating-up phases into count.
The military administration maintained uniformity. A sort of reference-vehicle was decided for each vehicle class, this was then, conceivably, produced by several manufacturers, not bad earnings! Thus, Mercedes unwillingly built the Opel Blitz and with changes, established the basis of it's utility vehicle sector after the war. A typical aspect of the much loved pre-war Opel Blitz was the petrol engine, which also did service in the Opel Kapitšn. It was Mercedes who first developed the respective Diesel engine.
We've nearly forgotten an important acquisition from the aircraft construction field, the petrol injection. It was created to solve the problems that the carburettor had at high altitude and, for a long time, played only a minor role in road-vehicle construction. Also the famous compressor engines of the 1930s worked with carburettor technology. In the form of direct injection, this technology places higher demands on the pressure development, it is interesting however, e.g., for two-stroke engines because it minimizes scavenging losses.
The direct injection was brought out by the Gutbrod company in 1951, however, with the engineer responsible, it landed at Mercedes and became famous in the 300 SL, despite the fact that all the other vehicles bearing this marque, had to be satisfied with indirect injection. Only in the late 1990s was it first used by Mitsubishi and then widely taken up again. Otherwise, the engine concepts from before the war were brought out again after the war.