Rudolf Diesel
Rudolf Diesel receives a patent for the diesel engine.
Rudolf Diesel patented a compression-ignition engine that drastically improved fuel efficiency over steam power.
The Drive for Efficiency
Rudolf Diesel was a German engineer obsessed with thermal efficiency. He knew that steam engines wasted up to 90 percent of the energy in their fuel. His goal was to build an internal combustion engine that could approach the theoretical maximum efficiency of the Carnot cycle.
His path to this invention was fraught with danger. While experimenting with high-compression steam engines using ammonia vapor, a cylinder head exploded. The blast nearly killed him and left him with long-term health and eyesight problems. It was during this period that he began conceptualizing a new type of engine.
The Patent and Theory
In 1892, Diesel considered his theory complete and received German patent DRP 67207. He published a treatise in 1893 titled Theory and Construction of a Rational Heat-engine. This document outlined a design where air was compressed internally to high temperatures. Fuel was injected at the end of the compression stroke, igniting on its own without a spark plug.
This compression ignition method was radically different from contemporary gas engines. The source text notes that the engine was smaller and lighter than steam engines. It achieved fuel efficiency ratios 75 percent higher than the theoretical efficiency of steam engines. Diesel later realized errors in his initial theory and filed a corrected patent application in 1893.
From Theory to Reality
Diesel needed industrial partners to test his fragile designs. Heinrich von Buz of Maschinenfabrik Augsburg and the Krupp firm provided support. The first successful engine, Motor 250/400, was officially tested in 1897. It was a four-stroke, single vertical cylinder engine producing 25 horsepower.
The success of this prototype revolutionized the engine manufacturing industry. It generated significant royalties for Diesel. The engine could run on various fuels, including petroleum and vegetable oils like peanut oil. This versatility and efficiency laid the groundwork for its future dominance in ships, trucks, and locomotives.