The German empire was always in a landlocked and surrounded condition. Cornered in every way, it has constantly relied on a combination of water access, through its great rivers, and on its massive underground coal reserves to flex its muscles before the world.
It is no surprise, then, when in the 1880s Rudolf Diesel became fascinated with the problem of steam engine efficiency. Steam engines were, of course, the motor of choice in this era, running stationary heavy machinery, canal boats, and railroad locomotives.
In the city of Munich, Diesel began studying the Carnot cycle, a theoretical powerplant description of an engine, which operated in tandem between two heat reservoirs. These early studies led him to design his "economical thermo motor" in 1890. By 1893, with patent in hand, he obtained the required financial backing from both the Augsburg and Essen establishments. The original idea, of course, was to burn coal dust, enormous amounts of which were being piled up in the Ruhr Valley as waste products of the coal industry. When a prototype engine exploded, the coal dust angle proved non-functional. In 1897 a new 20-horsepower engine fueled by oil injected with pressurized air ran successfully. Diesel's engine, which cycled without spark ignition, was not his primary aim. Actually, it was the effect of utilizing ultra-high compression ratios to achieve the thermodynamic principle that gave his invention its great efficiency. Diesel was equally pleased that his unit demonstrated half the fuel consumption of the current gasoline engines.
It should be noted here that Diesel had always planned for his engines to operate on alternative fuels-if not with his original coal dust idea, then oil-based fuels derived from plant materials. In fact, he ran several engines on peanut oil. Germany's economic structure, however, soon dictated that like the rest of world, petroleum-based diesel would become the fuel of choice.
At the turn of the century, Diesel's invention began to parallel its steam competitors in the large stationary applications. Despite their fuel efficiency (better than gasoline units), these early pieces were extremely heavy with regard to any form of automotive application. Their limitations were due to roughness, excess smoke, and an inability to rev. Truck platforms, however, began to utilize them out of necessity.