Diesel Engine
A diesel engine is a type of internal combustion engine that operates using the principle of compression ignition, where fuel is ignited by high pressure and temperature rather than a spark. Developed by Rudolf Diesel in the late 19th century, it distinguishes itself from earlier engines by compressing air to a significant pressure before adding fuel, allowing for various fuel types to be used, including diesel fuel, alcohol, and even vegetable oils. Despite their initial large size and weight, diesel engines have become integral to various applications, especially in trucks, ships, locomotives, and stationary power plants due to their durability and long lifespan.
Diesel engines are known for their fuel efficiency and lower running costs compared to gasoline engines, making them a popular choice in Europe, where diesel vehicles are more prevalent. However, the early models faced challenges such as pollution and bulkiness. Over time, advancements have made diesel engines more practical for a wider range of vehicles, including passenger cars. In recent years, there has been a growing interest in biodiesel—alternative fuels derived from renewable resources—as a response to rising fuel prices and environmental concerns. Overall, diesel engines play a significant role in transportation and energy sectors globally.
Diesel Engine
Date February, 1892
German thermal engineer Rudolf Diesel developed and patented a prototype of an internal combustion engine that he believed could one day be operated on vegetable oils and other plentiful fuels rather than on petroleum.
Locale Berlin, Prussia, German Empire (now in Germany)
Key Figures
Rudolf Diesel (1858-1913), German thermal engineerSadi Carnot (1796-1832), French physicistAlphonse Beau de Rochas (1815-1893), French engineer and inventorNikolaus August Otto (1832-1891), German engineer and inventorEugen Langen (1833-1895), Otto’s partner in building internal combustion enginesÉtienne Lenoir (1822-1900), French engineer and inventorCarl von Linde (1842-1934), German refrigeration engineer and industrialist
Summary of Event
Rudolf Diesel spent his early years in Paris, where he lived with his parents, natives of Bavaria holding Bavarian citizenship. When the Franco-Prussian war erupted in 1870, the Diesel family, faced with the prospect of deportation from France, moved to London. Soon, young Rudolf was sent to Augsburg, Germany, his father’s home town, to continue his schooling.
When he was old enough to begin his higher education, Diesel entered the Technische Hochscule, a university-level technical institute in Munich, where he showed a particular aptitude for engineering. Carl von Linde, a noted authority on refrigeration engineering who was associated with the Technische Hochschule, recognized Diesel’s exceptional aptitudes while the youth was still a student and took a special interest in him. With von Linde’s encouragement, Diesel performed experiments that involved using ammonia to fuel an expansion engine. In 1880, von Linde employed Diesel in his corporation, stationing him in Paris. By 1890, Diesel moved to Berlin to take a new job with von Linde’s company. It was there that he first conceived of developing an internal combustion engine different from those produced earlier by Nikolaus August Otto in Germany and Étienne Lenoir in France.
Diesel’s ideas were not yet fully formed, so in February, 1892, he applied for a development patent on his engine. The German government issued the development patent, and the following year, Diesel published a more comprehensive explanation of the engine as he conceived it. This description, Theorie und Konstruktion eines rationellen Wäremotors (theory and construction of a rational heat motor), enabled Diesel to obtain a patent in 1893 for the compression-ignition engine that is now commonly referred to as the diesel engine.
The concept of compression ignition was articulated as early as 1824 by the French physicistSadi Carnot , but no practical application of this technology appeared until 1876, when Otto built a working model of an engine in which the mixture of fuel and air was compressed in the cylinder before ignition. Fourteen years earlier, Alphonse Beau de Rochas had conceived theoretically of an engine built according to these principles, but he did not create any working models. Lenoir began building internal combustion engines in 1862 and produced about five hundred of them, all based upon concepts relating to the steam engine . Lenoir’s engines used sliding valves to admit and dispel combustion gases.
It took another fourteen years after Otto unveiled his model in 1876 before Diesel conceived of his engine in detail. Otto and Eugen Langen—his partner in their joint venture, the Gasmotorenfabrik—built some five thousand engines before Diesel patented his engine. Their engines were more practical than Lenoir’s in that they used flywheels to carry the pistons through their rest phases. Diesel’s engine differed from those developed by Otto and Lenoir in that its power was achieved by compressing air in the cylinder. The air was compressed to a pressure of about five hundred pounds per square inch, at a temperature of about one thousand degrees Fahrenheit. Fuel was then ignited by pressure rather than by a spark and burnt before the piston descended. This action occurs so slowly that there is no significant increase in pressure resulting from the ignition. Previous engines had depended upon a spark to ignite the fuel in their cylinders. Diesel’s model depended on heated, compressed air to achieve this ignition.
Whereas previous internal combustion engines had been powered by gasoline, Diesel’s engine could operate on a variety of fuels. Indeed, his first working model was fueled by powdered coal, which was in plentiful supply but which quickly proved to be a less-than-ideal fuel for the engine. Diesel soon replaced powdered coal with alcohol and other liquid fuels.
As soon as the idea of Diesel’s engine was protected by a patent, the inventor set about building working models. He received backing and encouragement from the Maschinenfabrik of Augsburg and the powerful Krupp enterprises. By 1897, he had produced several working models, the most promising of which was a four-stroke engine with a single perpendicular cylinder that served as the compression chamber. This early diesel engine delivered twenty-five horsepower.
Remarkably, Diesel’s engine was sufficiently simple in its design that its commercial possibilities became evident quite quickly. The engine was pressed into service in a variety of ways that, by the turn of the century, brought Diesel remarkable wealth through royalties. For all of its promise and actual success, however, the engine was not without serious drawbacks. The early diesel engines were much larger and considerably heavier than the gasoline engines they were designed to replace. They also produced considerable air pollution, but comparable gasoline engines caused comparable amounts of pollution as well.
Because of their size, the earliest diesel engines were most appropriate for use as stationery sources of power. Eventually, they were used to power large ships and locomotives. During World War I, they provided power for Germany’s fleet of submarines. It was not until the second quarter of the twentieth century, however, that diesel engines were commonly used to power trucks, which currently remains one of their major applications. Diesel engines have a much longer life than gasoline-powered engines, and they require considerably less upkeep than their gasoline-powered counterparts. They also can burn less expensive fuel, including easily replenishable vegetable oils.
Significance
Diesel engines are the engines of choice for most trucks, locomotives, ships, buses, and stationary power plants. They are durable engines that, when Diesel first developed them, were too heavy and cumbersome to be practical for any but the largest vehicles. The power and cost-efficiency of the diesel engine made it possible for such vehicles to be put to work, however, and in some cases made it possible for them to exist at all.
Eventually, the weight of the diesel engine was reduced sufficiently to make practical its use in private passenger vehicles. Diesel-powered passenger automobiles have generally been more popular in Europe than in the United States, probably because the price of gasoline is much higher in Europe than it is in the United States, making diesel automobiles practical choices purely on economic grounds. Diesel envisioned his engine as running on vegetable oils and other renewable resources. The oil industry, however, created a new type of gasoline that could power a diesel engine so that it could still make profits from diesel-powered automobiles. During the early twenty-first century, a new interest in the use of biological fuels in diesel engines, commonly referred to as “biodiesel,” began to gain strength, motivated by increasing gasoline prices.
Bibliography
Alternatives to Traditional Transportation Fuels, 1993. Washington, D.C.: Energy Information Administration, 1995. A major section on diesel engines is informative in addressing alternative fuels, such as vegetable oils, that can be used in diesel engines.
Hill, Stephen H. Automotive Diesel Technology Programs. Washington, D.C.: United States Department of Energy, 1977. Hill discusses in detail the potential of using diesel engines in private passenger automobiles as a means of reducing the consumption of petroleum-based fuels in the United States.
Jefferson, C. M., and R. H. Barnard. Hybrid Vehicle Propulsion. Boston: WIT Press, 2002. The authors’ three-page discussion of the diesel engine is informative, especially the section on the efficiency of diesel engines. The authors discuss the advantages of diesel engines in hybrid vehicles.
Nitske, Robert, and Charles Morrow Wilson. Rudolf Diesel: Pioneer of the Age of Power. Norman: University of Oklahoma Press, 1965. This well-researched book’s age does not diminish its importance to those interested in the development of diesel technology and in the life of Rudolf Diesel. Strongly recommended.
Rosbloom, Julius. Diesel Handbook: A Practical Book of Instruction for Engineers and Students on Modern Diesel Engineering—Land, Marine, Locomotive, and Automotive and Portable Installations. Jersey City, N.J.: Diesel Engineering Institute, 1935. This early consideration of diesel engineering demonstrates the range of possibilities this technology permits. Despite its age, this is a valuable presentation.