In all together six series of experiments, the different variations were described by Rudolf Diesel. Basically, almost all fuel types were tested in the various test engines. Even a type of gasoline was used. Robert Bosch is also is said to have stood, together with Diesel, in front one of the test engines, without having any idea how to solve the problems. Indeed, there were no problems with the electrics, simply because there were none.
All in all, it took 3 ½ years, from August 1893 until February 1897 to obtain the official acceptance and the confirmation of the enormous efficiency of 26.2 percent, which was an incredible improvement over the steam engine and almost twice as high as that of the Otto-engine. In the meantime, measurements taken from the non-functioning predecessors had already shown that the theoretical guidelines were understandable in the practice. Nevertheless, of course, the enthusiasm for the partial fulfillment is great.
One should also not forget the work done by others who were involved in this project. E.g., there was the meticulous senior engineer, Vogel and the two mechanics, Linder and schmucker, who were passionately involved with the machine. After the acceptance of the test-engine the work really took off, because it had now been transformed into a marketable product. Diesel was much less involved with this part than he was with the creation of the test-engines. From now on he would be struggling more for the preservation and distribution of his patent-rights.
The last of the, in view of their size and still relatively low performance, engines was not distinguished by the fact that it could be economically built. It was, the same as its direct successors, equipped with a cross-head. Apart from that, it was fitted with a complicated compressor, which served both the starting off from a stationary position and the injection of the fuel.
At least almost every fuel could be used. Diesel himself even ran tests using unaltered natural products such as e.g., cold-pressed rapeseed-oil. Otherwise, both of the first sold engines were so difficult to start up, that basically a new group had to be formed in MA(N)*, which would deal intensely with further developing. Whereby apparently, no part of the engine was left in ist original condition. The others who exploited the Diesel-patent had even more problems producing a usable engine. 05/14