Diesel Engine Still Trucking as Designers Gain Higher Efficiency in Hunt to Cut Emissions

New York — October 20, 2009 — The environmental demands on trucks are becoming steadily tougher, and already this autumn emissions will be toughened still further in Europe. Pressure for the development of environmentally optimized technology is increasing, but the answer need not lie solely with electric and hybrid solutions.

Tomorrow's most energy-efficient engines are already more than a 100 years old. All the indicators are that the diesel engine still has a lot to give.

Rudolf Diesel could scarcely have been aware of the historic importance of the patent application he submitted to Kaiserlichen Patentamt in Berlin in February 1892. His application bore the modest title "Neue, rationelle Wärmekraftmaschine" ("New Efficient Thermal Engine"), yet the invention he presented was anything but modest. Behind patent number 67207 lay a combustion engine that was far more efficient than any of the steam- or gas-powered engines that were common at the end of the 19th century.

Today the diesel engine is one of the most exciting and promising technologies in the hunt for new engine solutions for an increasingly eco-aware and resource-efficient world. The reason for the diesel engine's success lies in Rudolf Diesel's original idea: to create an engine with the maximum "thermodynamic efficiency rating" — something that is achieved when as much as possible of the fuel's energy is used to propel the vehicle instead of literally going up in smoke. What is special about the diesel engine is that it compresses both air and fuel under immensely high pressure. When the fuel in the cylinder ignites owing to the heat generated by the high degree of compression, this generates the power that sets the piston in motion.

The first functioning diesel engine came in 1897 and it boasted an efficiency rating of 26 percent, way beyond the mere 12 percent efficiency of the contemporary steam engine. Today's modern trucks are powered by diesel engines with an efficiency rating of about 46 percent. A significant development, to say the least.

So what exactly has happened over these past decades?

Technical University of Munich expert in combustion engines Maximilian Prager
Technical University of Munich expert in combustion engines Maximilian Prager

Volvo Trucks engineer and project manager for the new D16 engine Henrik Ask
Henrik Ask, engineer and project manager for the new D16 engine at Volvo Trucks (photo: Pontus Johansson)

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