Trucking History

Building Blocks of the Trucking Industry – the Diesel Engine

NOTE: The following is the first installment of an on-going series on the technologies that helped build and shape today’s trucking industry. This story looks at how and why the diesel engine was developed and the circumstances surrounding the mysterious death of its inventor before the engine that bared his name really took off.

The date was Feb. 17, 1897. The place was the Maschinenfabrik Augsburg manufacturing facility near Munich, Germany. The inventor of the diesel engine, Rudolf Diesel, knew the technology he had been developing for the past four years, and which he was introducing that day, had the potential to dramatically change how people and freight move across the globe. But it’s not clear if he could have foreseen just how much his invention would change things. After all, the diesel engine eventually became the lynchpin for an industry that hauled what would have likely seemed to him to be an unimaginable amount of cargo across the United States. More than 3.4 million Class 8 commercial trucks moved over 10 ½ billion tons of freight across the United States in 2017. And a vast number of those trucks were powered by the engine that bore his name. To move an equivalent amount of freight overseas in 1897 would have required nearly 2 million double-screw-propelled 300-foot-long steam freighters.

Let’s put it another way. With the ships of the U.S. Merchant Marine fleet having carried 4.4 million tons of freight in 1890, it would have taken the equivalent of nearly 2,400 U.S. Merchant Marine fleets to transport the same amount of cargo that diesel-powered commercial trucks carried across the United States in 2017. (Unfortunately, since we weren’t able to find how many ships the U.S. Merchant Marine operated in 1890, we can’t tell you how many ships that would have been).

If At First You Don’t Succeed…

Four years earlier, Rudolf’s initial attempts to produce a working engine that could surpass the omnipresent steam engine failed. However, the 30-something engineer trained at the Munich Polytechnic University, what is today called the Technische Universitat Munchen, knew through his knowledge of thermodynamics that his idea of burning fuel slowly, and at higher pressures, would work. Rudolf was the protégé of Carl von Linde, the head and founder of the thermodynamics laboratory at his alma mater in Munich. Rudolf came up with his idea for his compression engine from a fire pistol von Linde had been given as a present during a trip to Pinang Island in Southeast Asia and he used to light a cigarette. The young engineer was convinced he could come up with new technology that could replace the steam engine. Theoretically, he knew his invention could generate propulsion at far greater efficiency than the 10 percent the steam engine could achieve. Since it had far fewer moving parts than a gasoline-powered engine, Rudolf also knew this new diesel engine would be much more robust. And it would be cheaper to operate since it burned heavy oil.

After convincing the president of Maschinenfabrik Augsburg – the forerunner of MAN, to provide the equipment, manpower and funding to develop the engine, Rudolf set to work on it. For nearly four years, he continued that work, but didn’t come up with a prototype that offered satisfactory results until that fateful day in February of 1897. Powered by kerosene – or what would eventually be marketed as the No. 1 grade of diesel fuel, the 3-meter-high A-frame engine with the cylinder mounted on a crosshead, (a design element borrowed from the steam engine), and flywheel at the side, produced 18 horsepower at a remarkable efficiency of 26.2 percent. This performance outclassed all other forms of propulsion available at the time and it worked without requiring an ignition device, a boiler or a coal bunker.

Two German Manufacturers With Long Names Become MAN

A year after Rudolf developed his first working prototype engine, his company and Maschinenbaugesellschaft Nurnberg combined and eventually became Maschinenfabrik Augsburg Nurnberg or MAN. For the next several years, MAN engineers worked at perfecting the diesel engine to make it more viable for the market. They developed direct injection, exhaust turbocharging and added improved forms of combustion. During the first years of the 20th Century, MAN engineers did away with the crosshead design. This produced a substantial reduction in the weigh-to-horsepower ratio and dropped its fuel consumption by 23 percent.

Even the Best Engineers Don’t Always Make the Best Business Decisions

Failing to see the importance of this work in making his invention more commercially viable to a wider market, Rudolf grew increasingly frustrated by the work of the other MAN engineers and complained bitterly that few factories were up to the task of making his engine. Historian Daryl Worthington wrote in his article “The Mysterious Death of Rudolf Diesel,” posted on the New Historian website, that while Rudolf saw any further development as unnecessary mop-up work, other MAN engineers and company leaders knew it was quite necessary. They recognized that beyond its use in ships and ferries and as stationary power, diesel engines couldn’t work very well in road and rail vehicles due to design limitations.

The engine lacked the right accompanying powertrain, it was too heavy and its fuel compressor injection system too complicated. Six years after he developed the first commercially viable diesel engine, Rudolf mysteriously vanished during a crossing of the S.S. Dresden on the English Channel from Ghent, Belgium, to London, where he was scheduled to attend the Consolidated Diesel Manufacturing conference. His badly decomposed body was found floating in the North Sea several weeks later by the crew of a Dutch tugboat operating there. There was no room on the boat to store his body, so the crew gathered personal items from the corpse. Rudolf’s youngest son, Eugen, later identified the items as belonging to his father. Since the body was never recovered, an autopsy couldn’t be done to confirm the cause of death.

Suspicious Circumstances Surround the Death of (Rudolf) Diesel

Some, including members of Rudolf’s family, have never believed that the cause of death was suicide even though there’s some strong circumstantial evidence to support that conclusion. Even though worldwide license agreements for his diesel engine made him a millionaire, because of a series of poor business decisions, Diesel faced bankruptcy when he disappeared. His patents for the diesel engine in the United States expired in 2012, which meant he wouldn’t be getting as much revenue from licensing deals. Plus, he withdrew a large amount of cash and gave it to his family before leaving for the conference. And none of his bank accounts had enough money to cover interest payments on his debt due just two days after he left for the conference. Despite those circumstances, conspiracy theorists believe that the German government had Diesel killed because he was about to sell his diesel engine technology – a system used at the time in the construction of all submarines – to a British company.

Meanwhile war between Germany and the Austrian-Hungarian Empire and the rest of Europe led by Great Britain and France appeared more and more likely. The German Armed Forces Administration pressured MAN into abandoning its manufacturing license agreement with a Swiss automobile factory and ramping up production of trucks for the expected war effort. The company eventually halted all development work on the diesel engine.

Following the war, MAN engineers resumed that development and eventually solved the key roadblock to the diesel engine’s successful use as a truck engine – direct injection of fuel into the combustion chamber using a high-pressure pump. This refinement greatly simplified the engines and their maintenance. It also opened up the way for smaller engines and higher engine speeds.

MAN Introduces Machine at Berlin Auto Show

At the German Automobile Show in Berlin in 1924, MAN presented the first diesel truck equipped with a 4-cylinder engine with direct fuel injection. This engine:

  • Delivered 45 hp @ 1,050 rpm (crank shaft revolutions);
  • Consumed 200 grams of fuel per horsepower hour (or about 10 liters per hour assuming the engine burned No. 2 diesel fuel with a density of 0.84 kg per liter and not a heavier grade diesel fuel);
  • Weighed significantly less than the first commercially viable engine Diesel developed 27 years earlier. It was barely heavier than a conventional carburetor engine. (The Benz-Gaggenau S100 4-cylinder carburetor engine, which delivered 35 hp @1,200 rpm, weighed about 900 pounds).

Check out the original internal combustion engine patent from Rudolf Diesel officially patented on August 09, 1898. Original Patent 1898


MAN Nutzfahrzeuge AG company archives – – “A brief biography of Rudolf Diesel,” authored by Martin Leduc, 1999, updated 2008, 2013 –

Car Magazine – “Diesel: From Coal to Common-Rail,” June 10, 2009 –

MAN Museum –—an-overview

New Historian – “The Mysterious Death of Rudolf Diesel,” posted by Daryl Worthington on Sept. 28, 2015 –