Keeping The World Moving: The Development and Innovation of the Diesel Engine

However, even with our love for diesel engines and everything related to them we often don’t think about where they actually come from. After all, sometimes it feels like the diesel engine has been around forever. It might feel that way, but the diesel engine and its concepts are really only a little over a century old. There was a lot of work that went into the development of the diesel engine as it exists today, but one man can be credited with the foundational work that has helped make the world of diesel engines (and, by extension, Dieselmatic!) possible: Rudolf Diesel.

The Early Days: Youth & Education

Before we get into how Rudolf Diesel developed his famous engine, it’s important to understand where he came from and his upbringing.

Rudolf Diesel was born in 1858, on the 18th of March, in Paris, France, as the second of three children to Bavarian immigrants Elise (nee Strobel) and Theodor Diesel. His mother was the daughter of a Nuremberg merchant, who his father met in Paris in 1855 after leaving his hometown of Augsburg, Bavaria, in 1848; his father became a leather goods manufacturer after marriage.

Young Rudolf would end up working with his father due to the family’s financial difficulties, delivering his father’s goods to customers throughout the city. Attending a Protestant-French school, this would be where Rudolf’s interests in society and technology would manifest. As an excellent student, Rudolf would receive the Société pour l'Instruction Elémentaire (one of France’s oldest and largest secular educational societies) bronze medal at age 12, and would make plans to enter the Ecole Primaire Supérieure (a form of higher primary education schools in France that offer vocational and technical classes) in 1870. However, this would not come to pass.

The Franco-Prussian War would break out in 1870, and Diesel’s family would fall victim to the mass deportations of German residents from France. The family would end up in London, where Rudolf would begin attending an English-language school. Eventually, with his parents desiring Rudolf to learn German and keep with his heritage, he was sent to live with his aunt and uncle in Augsburg in order to become fluent in German and continue his schooling; his uncle taught mathematics at the Knogliche Kreis-Gewerbeschule (Royal County Vocational College).

When he turned 14, Diesel wrote his parents explaining his wish to become an engineer. Finishing his basic education in 1873 at the top of his class, he would subsequently attend the Industrial School of Augsburg, which had been recently founded. In 1876, despite his parents wishing him to immediately start working (as was common back then), Diesel would receive and accept a merit scholarship from the prestigious Royal Bavarian Polytechnic of Munich (now known as the Technical University of Munich). There, he would start the education that would lay him on the path to his most significant invention.

Arriving At An Idea

Although Diesel missed the July 1879 graduation date due to falling ill with typhoid, the subsequent recovery and waiting period allowed him to gain some practical engineering experience while working at the Sulzer Brothers Machine Works in Winterthur, Switzerland.

Diesel would graduate in January 1880 with the highest honors and travelled to Paris, where he worked for his former professor Carl von Linde (the father of refrigeration) in designing and constructing a modern ice and refrigeration plant; Diesel would become director of said plant in 1881.

Rudolf would marry Martha Flasche in 1883, and would eventually move to Berlin in early 1890 with her and their three children (Rudolf Jr., Heddy, and Eugen), gaining management of Linde’s corporate research and development department. He’d gained several patents while under Linde, but couldn’t use them on his own precisely because they were developed while under Linde; this led him to branch out away from refrigeration and into other avenues.

Diesel’s initial work consisted of utilizing steam, with his understanding of both the concepts of thermal and fuel efficiency leading to the construction of a steam engine with ammonia vapor as a power source. However, this engine exploded and nearly killed him. Another test in high-compression cylinder pressures experimented with the strength of iron and steel cylinder heads. This would result in another accident, an explosion which would put Diesel in the hospital and inflict him with health and eyesight problems from then on.

After these setbacks, and further development and theorizing, Diesel would arrive at the idea of his own internal combustion engine. While internal combustion engines had been around for decades (the first industrially-viable version had been patented and deployed in 1823), Diesel’s development was different. He wanted to develop an engine that could approach the maximum theoretical level of thermal efficiency as outlined by the Carnot cycle.

What is the Carnot cycle?

Well, it’s the thermodynamic cycle that basically every engine in existence operates under, and refers to a system transferring energy in the form of heat between hot and cold reservoirs, with part of this energy being transformed into work done by the system. Diesel knew that steam engines of the time wasted as much as 90% of their fuel’s energy while under operation; he wanted to build an engine that was much more efficient.

Crafting A Foundation

Once Diesel finalized his idea, he would publish his treatise, called Theory and Construction of a Rational Heat Motor. This treatise would become the founding document behind Diesel’s development of the diesel engine. Originally written in German, a translation into English was made in 1894; the German first edition had one thousand copies printed.

After sending copies to some of Germany’s most renowned engineers and professors, feedback was decidedly mixed. His theory’s critics were influenced by the technology and practices of the time; many thought that then-current machines couldn’t withstand the pressures called for, such as Eugen Langen (one of the inventors of the petrol engine). However, only a few critics (like engineer Wilhelm Zublin and professor Alois Riedler) realized the real flaw behind Diesel’s theorem: the type of compression he detailed, a isothermal-adiabatic type, was simply impossible because the hypothetical engine couldn’t perform any work because it would require so much compression to function.

However, others lauded Diesel’s ideas. Praise was enough that Maschinenfabrik Augsburg and Krupp’s Essen department formed the consortium that led to Diesel building his prototypes and realizing his theory’s flaws (in conjunction with the criticisms of Riedler and Zublin).

Despite this change in course, Diesel would never publicly admit his mistakes and changes in his theory; this was primarily because a public admittance of this fact would have rendered his patent obsolete and opened the door to others building the engine without a license.

Experimenting and Prototyping

Diesel would begin working with Maschinenfabrik Augsburg and Krupp’s Essen department to begin fully realizing his, until then, theoretical engine based on his theories outlined in Theory and Construction of a Rational Heat Motor. After modifications to the design (accompanying a modification in his theory), Diesel would complete his first prototype on 12 July 1893. Known as the Motor 150/400, preliminary tests proved Diesel’s initial concepts; the Motor 150/400 was eventually converted to a second prototype, the Motor 220/400, in October 1895. However, testing with this second prototype made it clear that a completely new engine was necessary.

Before building the new prototype, Diesel would build a new design bureau directly into the Augsburg testing laboratory. A young engineer, Imanuel Lauster, was the main individual responsible for drawing the plans of what would become the Motor 250/400; once these drawings were complete, construction commenced on 30 April 1896.

Finalization and Success

After testing with the various components and modifications where needed (the cylinder head needed several redesigns before it was strong enough), the final prototype was completed on 6 October 1896 and ready for further testing. Lauster would be rewarded for his design, seeing a pay raise and a 3,000 mark bonus; finalizing modifications were made in January 1897.

Success came in February 1897, when the engine was tested by industrial engineer and university professor Moritz Schroter. Although the fuel system would prove troublesome, the test was enough of a success that several engineers and industrialists were convinced the engine was ready for production. As a result, several firms would buy licenses to manufacture, believing their own copies would work without issue; this was of course only due to the fact that the Motor 250/400 was cared for and maintained extensively.

Unsurprisingly, follow-up copies from these other firms wound up failing left and right. This was due both to the differing conditions these engines were built under and the fact they were treated like conventional steam engines common in industry at the time; this meant they were often overloaded and suffered from numerous defects like piston and fuel injector failures.

These cascading problems almost caused the complete demise of the diesel engine before it really took off, but there was just enough success and belief that the engine chugged on. The Danish shipyard Burmeister & Wain would redesign the fuel injector’s atomizer, a major problem in preceding engines.

The first American diesel engines would actually be manufactured under companies owned and founded by Adolphus Busch, of Anheuser-Busch fame, with Rudolf Diesel acting as a consultant. Adolphus would acquire the manufacturing rights in 1897, founding both the Diesel Motor Company (1898-1902) and the American Diesel Engine Company (1902-1911), which would be eventually succeeded by the Busch-Sulzer Bros. Diesel Engine Company in 1911. Under these companies, diesel engines would power everything from breweries to the U.S. Navy’s first ocean-going submarines.

Meanwhile, in Canada, the first diesel-electric train would be pioneered by CN Railways starting in 1929, although diesel-electric powered trains wouldn’t fully replace steam engines until around 1960.

The Unfortunate & Mysterious Death of Mr. Rudolf Diesel

Although further development would occur to prove the engine truly commercially viable, Diesel was not so fortunate. He would struggle to market the engine effectively despite being its inventor, especially when many other engineers and companies were also improving on his work. It also didn’t help that he struggled to find common ground and relations with other engineers. It’s likely that these problems lead to what happened next.

In September 1913, Diesel would board a steamer bound for London from Antwerp, the SS Dresden. Retiring to his cabin late that night, he was never seen again. Ten days later, a Dutch pilot boat would encounter a badly decomposed body floating in the Eastern Scheldt. Due to the corpse’s condition, only personal effects were taken; these were later identified by Diesel’s son Eugen as belonging to his father.

Although theories abound as to what happened (from the German military assassinating him to Diesel faking his death), it is likely he committed suicide.

The Diesel Legacy

Despite his mysterious death, Rudolf Diesel has left an enduring legacy on not just the vehicle industry but helped fundamentally shape the world as we know it today. Diesel engines are at the heart of the world’s most important industries, from shipping to construction to transportation and everything in-between. Diesel’s invention and widespread proliferation is also what allowed the development of the common environmental standards employed the world-over by today’s engine manufacturers and government agencies.

But, Rudolf Diesel’s legacy goes beyond just developing the diesel engine. For one thing, he was also responsible for developing the fuel said engine runs on. Although he didn’t intend his engine to run on anything specific (indeed, the first engines ran on everything from crude oil to lamp oil to even fuel derived from coal tar and peanuts), in 1899 he would eventually begin using coal-dust derived fuel which would help lay the groundwork for the more common diesel fuels developed in the 1930s and post-war periods.

Rudolf also helped develop the foundation of biodiesel fuels which are entering increasing prominence in today’s diesel vehicles with the rise in fuel costs. Even the original diesel engines could run on things like vegetable and peanut oils with no modification necessary; an engine demonstrated by the Otto company at the 1900 Paris Exhibition ran on peanut oil so smoothly that no one noticed. Diesel was always supportive of the use of alternative fuels; in a 1912 speech, he commented that “the use of vegetable oils for engine fuels may seem insignificant today but such oils may become, in the course of time, as important as petroleum and the coal-tar products of the present time.”

Today, a physical memorial stands to Rudolf Diesel in his hometown of Augsburg, Bavaria. A Japanese garden, it was created after the founder of Japanese engineering company founder Magokichi Yamaoka visited Augsburg in 1953 to honor Diesel but found no memorial; the grove was meant to both honor Diesel and his engine in addition to strengthening German-Japanese ties. The grove was designed by architect Sakakura Junzo and was inaugurated on December 10, 1956. It was transported and rebuilt in Augsburg in Wittelsbacher Park with the ceremonial handover on October 5 and 6, 1957 (the anniversary of Rudolf Diesel’s 100th birthday).