quality:corruption, structural:scholar_edition
Career

One of Diesel's professors in Munich was Carl von Linde. Diesel was unable to graduate with his class in July 1879 because he fell ill with typhoid fever. While waiting for the next examination date, he gained practical engineering experience at the Sulzer Brothers Machine Works in Winterthur, Switzerland. Diesel graduated in January 1880 with highest academic honours and returned to Paris, where he assisted Linde with the design and construction of a modern refrigeration and ice plant. Diesel became the director of the plant a year afterwards.

In 1883, Diesel married Martha Flasche, and continued to work for Linde, gaining numerous patents in both Germany and France.

In early 1890, Diesel moved to Berlin with his wife and children, Rudolf Jr, Heddy, and Eugen, to assume management of Linde's corporate research and development department and to join several other corporate boards. Since he was not allowed to use for his own purposes the patents he developed while an employee of Linde's, he expanded beyond the field of refrigeration. He first worked with steam, his research into thermal efficiency and fuel efficiency leading him to build a steam engine using ammonia vapor. During tests, however, the engine exploded and almost killed him. His research into high-compression cylinder pressures tested the strength of iron and steel cylinder heads. One exploded during a test run. He spent many months in a hospital, followed by health and eyesight problems. It was during this year that Diesel began conceptualising the idea of a diesel engine.

Ever since attending lectures of von Linde, Diesel worked on designing an internal combustion engine that could approach the maximum theoretical thermal efficiency of the Carnot cycle. In 1892, after working on this idea for several years, he considered his theory to be completed. In the same year, Diesel was given the German patent DRP 67207. In 1893, he published a treatise entitled Theory and Construction of a Rational Heat-engine to Replace the Steam Engine and The Combustion Engines Known Today, that he had been working on since early 1892. This treatise formed the basis for his work on and development of the diesel engine. By summer 1893, Diesel had realised that his initial theory was erroneous, leading him to file another patent application for the corrected theory in 1893.

Diesel understood thermodynamics and the theoretical and practical constraints on fuel efficiency. He knew that as much as 90% of the energy available in the fuel is wasted in a steam engine. His work in engine design was driven by the goal of much higher efficiency ratios.

As opposed to outside ignition applied against internal air and fuel mixture, air was compressed internally within the cylinder whilst heating, in order for the fuel to establish contact the air immediately before the compression period would end, thus igniting on its own. Therefore, the engine was smaller and weighed less than most contemporary steam engines, not to mention the fact that further fuel sources weren't required. Fuel efficiency was measured 75% above the 10% theoretical efficiency for steam engines.

In his engine, fuel was injected at the end of the compression stroke and was ignited by the high temperature resulting from the compression. From 1893 to 1897, Heinrich von Buz, director of Maschinenfabrik Augsburg in Augsburg, provided Rudolf Diesel the opportunity to test and develop his ideas. Diesel also received support from the Krupp firm.

Diesel's design utilised compression ignition as opposed to using spark plugs similar to gas engines, with the ability to be ran on biodiesel, if not petroleum -originating fuels. Compression engines are circa 30% more efficient over conventional gas burning engines, being mixed through forced compressed air within the combustion chamber, leading to a higher internal temperature, expanding at a higher rate and placing further pressure over the pistons that rotate the crankshaft towards a quicker rate.

Biodiesel often composed of synthesis gas originating from waste cellulose gasification, as well as extraction of lipids from algae, most frequently used by consisting vegetable oils and algae together under methanol transesterification. Numerous firms have developed different techniques in order to achieve such.

The first successful diesel engine Motor 250/400 was officially tested in 1897, featuring a 25 horsepower four-stroke, single vertical cylinder compression. Having just revolutionised the engine manufacturing industry, it became an immediate success, with royalties amassing great wealth for Diesel. The engine is currently on display at the German Technical Museum in Munich.

Besides Germany, Diesel obtained patents for his design in other countries, including the United States.

He was inducted into the Automotive Hall of Fame in 1978.