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March 15, 2022   |   Diesel Technology Forum

Policy Insider

Rudolf Diesel’s Enduring Invention

It is clear that we’re not done with enduring technologies that demonstrate continuous improvement of one man’s simple idea over 125 years ago, making the next generation of diesel even more energy efficient and lower in emissions


People don’t live to be 164 years old, but legacies and enduring technologies do. This week (March 18) marks what would have been the 164th birthday of the inventor of the diesel engine, Rudolf Diesel who died at sea in September 1913, but his legacy and his namesake invention live on.

Today, there are more diesel engines powering global economies around the world than ever before. If he were to come back today, Diesel would be astounded by the diversity of applications using diesel as the technology of choice; in awe of his engine’s modern-day performance and mystified by current day designs and configurations.

Diesel was a curious man when it came to so-called heat engines, even designing a solar-powered air engine. His inventions all centered around three common areas: the transference of heat based on natural processes and laws of physics; they had creative mechanical designs and were motivated by his concept of sociological needs - at the time enabling independent craftsman and artisans to compete with large industry. Diesel would be right at home today working to develop new fuels and energy sources to tackle a major sociological need, meeting the challenge of climate change. Indeed, thousands of engineers around the world are doing just that, reducing emissions, and making technology more efficient and boosting performance.

Two foundational aspects of the initial concept and engine design live on: it’s energy (or thermal) efficiency and ability to utilize biobased fuels like vegetable oils. Thermal efficiency is the ability to convert energy from one form (liquid fuel) to another (mechanical work) with as little waste as possible. 

Diesel’s first certification test for verifying efficiency and commercial suitability of his engine was done in 1897 on a single 10-foot iron cylinder with a flywheel at its base. That engine delivered about 18 hp (about 13.4kW), with mechanical efficiency achieving 75% and thermal efficiency 35%, with a net efficiency of 26% which was boosted to 30% later that same year. Considering that steam engines were only about 10% thermally efficient, the opportunities were obvious. Last year, the US Department of Energy and Cummins announced they had achieved 55% brake thermal efficiency in a heavy-duty diesel commercial truck engine as part of the SuperTruck II program.    

As for a preference for use of vegetable oils, that idea also was visionary in 1897. Now we consume billions of gallons of renewable biodiesel fuels, 3 billion in 2020 alone, and will need to use much more as we work to tackle climate change. The use of low carbon biofuels can reduce greenhouse gas and other emissions by 20-80% compared to conventional diesel fuel. Imagine the opportunity for using more biodiesel fuels in the millions of existing engines and vehicles, without the need for new vehicles or infrastructure!

Diesel also demonstrated the advantages of compression ignition engines yielding more complete combustion than spark-ignited gasoline engines. Modern day engineers seized on this advantage of compression ignition engines and now have incorporated some elements into gasoline direct injection (DGI) technology, making a gas engine more like a diesel engine.

It is clear that the future will be more eclectic with a widening range of fuels and technologies to power our global economies. It is also clear that we’re not done with enduring technologies that demonstrate continuous improvement of one man’s simple idea over 125 years ago, making the next generation of diesel even more energy efficient and lower in emissions. 

Resources:

Smil, Vaclav, Diesel Engine at 120
Bellis, Mary, "Rudolf Diesel, Inventor of the Diesel Engine", ThoughtCo, Aug. 28, 2020



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Allen Schaeffer
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aschaeffer@dieselforum.org
301-668-7230

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