A History of the Diesel Engine

The diesel engine differs from gasoline engines in one significant engineering fact: it achieves combustion of its fuel by the heat of compression in the combustion chamber rather than by the introduction of a spark. This difference dictates a different set of parameters for construction throughout the engine, but the diesel is still an internal combustion engine like its gasoline counterpart. Although many had tried to perfect this concept, it was Rudolph Diesel who first patented the design and became the namesake for this type of engine technology. Diesel applied for his patent with the Imperial Patent Office in Germany on February 27, 1892. His patent (#67207) was granted within one year. In 1893 his experiments created the first working model of a "new, efficient, thermal engine" which ran under its own power and developed a remarkable 26% fuel efficiency, more than double the then current standard set by steam engines. In February of 1897, Diesel introduced the first diesel engine which he felt could be put to practical use. It yielded an astonishing 75% fuel efficiency. He exhibited it at the Paris Exhibition Fair the next year. The fuel he used at the Fair was peanut oil. Throughout the process of development, Diesel had envisioned an engine that could be fueled with biological fuels, such as vegetable oil, as an alternative to fossil fuels, which were becoming monopolized in the world markets at the time.

Early diesel engines were very large and cumbersome, due to the density of materials needed to be used to withstand the high compression cycles of fuel ignition, and to the enormous size of fuel injection systems used at the time. That was not really a problem, since the first diesels were used primarily in industrial and marine applications, where size was really a non-issue. In many instances the diesel was still smaller than the steam engine it replaced. Common fuel efficiency ratings of these first diesels exceeded 50%, easily winning over buyers who had been using steam power for many years. Fuel for the new diesel was a much easier and space saving alternative to the coal/wood fired boilers of the steam age.

Diesel's new engine technology gained world-wide acclaim in a relatively short time. Even before the Paris Exhibition, Adolphus Busch, of Budweiser beer fame and a German ex-patriot in St. Louis, licensed the technology, in 1897, from Diesel for all rights to the engine in North America. Subsequent licensees include Branobel, in 1898, a Russian oil company seeking an engine able to be powered by unrefined oil, and engine builders Krupp and Sulzer, in 1899, who became major diesel engine manufacturers very quickly. By the turn of the new century Rudolph Diesel was a millionaire. Versions of his engines produced by his licensees were being used world-wide in mines of every description, oil fields, manufacturing industries, and, before long, in marine shipping. Since the diesel was able to operate at full capacity while creating very few noxious fumes, it was an immediate choice over gasoline engines, especially in confined spaces such as ship's holds and mine shafts.

Through continued developments and refining of diesel technology in the early 1900s, the diesel began to appear in smaller sizes. This technological advance centered around the cumbersome fuel injection systems of early diesels. The first diesel-powered fresh-water ships appeared, in France and Russia, in 1903. A year later the French launched a diesel-powered submarine. Fuel injection came to the forefront with the introduction of turbochargers and intercoolers in 1905. L'Orange and Deutz developed injection pumps with precision controlled needle injection nozzles in 1908, and a hemispherical combustion chamber a year later. The Norwegian ocean-going ship the Fram was the first with a diesel auxiliary engine in 1910. Two years later the Danish built the first ship to sail the oceans exclusively with diesel power, the Selandia.

The United States became the second nation to procure diesel powered submarines, in 1913. The next year the Germans had diesel powered U-boats. That particular development is surrounded with political mystery and intrigue. Rudolph Diesel was opposed to the political aspirations of the Germans at the same time that they were seeking to use his engines in their submarines. Politically, he was more closely aligned with Britain and France. The French already had a diesel-powered submarine, and the U.S. would have one that year (1913). Diesel was crossing the English Channel, on his way from France to discuss the use of his engine in British submarines, when he literally disappeared from the ship. This cleared the way for the Germans to use diesel engines in their submarines, which they did within a year. Most political theorists suggest the Germans had Diesel thrown overboard to quiet his opposition to their use of his engine. Although unprovable, that theory persists as the most logical explanation to the disappearance of one of the world's brightest inventors of all time.

Diesel engines have the highest fuel efficiency of all internal combustion engines due to the pressures they operate within during the combustion cycle. This extreme pressure cycle extracts the most energy per ounce out of the fuel, thus greatly enhancing fuel efficiency. By optimizing the capabilities of the fuel, a diesel engine is able to create horsepower and torque that regular gasoline engines cannot equal with the same amount of fuel. Some of the largest diesel engines, such as those used in marine and industrial applications, are also the most efficient, yielding fuel efficiency ratings above 50%. Currently, the largest diesel engine in the world, a Wartsila Sulzer marine diesel, develops 108,920 horsepower at a mere 102 RPM. Diesels are commonly used in locomotives, heavy equipment, and electric generating plants around the world. In the U.S. diesels are used in many high-torque, high-horsepower trucks, semis, and off-road vehicles. Currently, nearly 50% of all new car sales in Europe are diesel powered.

Since those first years the diesel engine has become more sophisticated and more widely accepted. Technological advances have affected the design of the engine in virtually all aspects. Initially, the advent of needle-valve controlled fuel injection allowed the engine to lose much of the bulk resident in the air cylinder controlled injection of early designs. Currently, electronic piezo fuel injection has carried that improvement a step further by precise injection timing that can be calibrated to the millisecond and can greatly increase horsepower, torque, emissions and fuel efficiency. This same piezo injection has also greatly alleviated the characteristic noise often associated with diesel engines. As the world struggles with the supply and/or control of fossil fuels, it would seem appropriate to delve into the endless possibilities of alternative fuels that could power diesel engines. Although current diesel technology concentrates on fossil fuels also, it is not inconceivable to picture diesels that could operate solely on bio-fuels that could be grown instead of pumped out of the ground. After all, a man named Rudolph Diesel came up with just such an engine over 100 years ago.