The Internal Combustion Engine

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The Internal Combustion Engine

Overview

Physicists call the internal combustion engine a "prime mover," meaning it uses some form of energy (e.g., gasoline) to move objects. The first reliable internal combustion engines were developed in the middle of the nineteenth century and were almost immediately put to use for transportation. The development of the internal combustion engine helped to free men from the hardest manual labor, made possible the airplane and other forms of transportation, and helped to revolutionize power generation.

Background

In 1698, Thomas Savery (c. 1650-1715), a British military engineer, built the "Miner's Friend," a device that used steam pressure to pump water out of flooded mines. A few years later, Thomas Newcomen (1663-1729) would expand upon Savery's design and create the first true engine. Newcomen's engine, unlike both Christiaan Huygens (1629-1695) and Savery's, used a piston that was attached to the engine itself. It could therefore produce continual (though hardly smooth) power.

Three conditions present during the nineteenth century encouraged the development of the internal combustion engine. The main condition was the demand for power presented by the Industrial Revolution. Second, physicists were beginning to understand the key concepts upon which the internal combustion engine was built. Third, the fuel needed to power the engine was becoming more available.

Between 1700 and 1900 scientists developed the field of thermodynamics, which gave inventors the tools to calculate the efficiency and power output of different types of engines. These calculations suggested that the internal combustion engine was potentially far more efficient than the steam engine (which, in contrast, was an external combustion engine, meaning it ignites the fuel outside of the engine itself).

The most important event in the early history of the internal combustion engine occurred in 1859 at the hands of Belgian inventor Jean-Joseph Etienne Lenoir (1822-1900). The Lenoir engine was both durable (some of them worked perfectly after 20 years of use) and, more importantly, reliable. Earlier versions of the engine were of poor quality and would stop operating for no reason. The Lenoir engine delivered continuous power and operated smoothly. In 1862, Lenoir invented the world's first automobile.

During the 1860s, Nikolaus Otto (1832-1891) began playing around with the Lenoir two-stroke and Alphonse Beau de Rochas's (1815-1893) theoretical four-stroke engines. Otto was a grocery salesman; he had no technical education or experience. In 1866, Otto—with the help of Eugen Langen (1833-1895), a German industrialist—developed the successful, but heavy and noisy Otto and Langen Engine. He continued to experiment with engines. In 1876 he released the "Silent Otto," the world's first four-stroke engine. In addition to being quieter than previous engines, the Silent Otto was also far more fuel efficient.

Otto's engine set the standard for the times. In fact, the fundamental design of modern engines remains identical to Otto's. As thermodynamics had predicted, the internal combustion engine was far more fuel efficient than the steam engine. Internal combustion engines that were quieter, cheaper to operate, and less bulky than steam engines began to appear in industrial plants throughout northern Europe.

In order for the internal combustion engine to make use of liquid fuels, it must first convert the liquid into a vaporous state. The next challenge for engine makers was to come up with a way to make this change happen. Between 1880 and 1900, different processes were invented to accomplish this task. Three methods were developed between 1885 and 1892: carburetion, hot bulb vaporization, and the diesel engine.

In carburetion, a device called a carburetor mixes air with vapors from the liquid fuel. The carburetor then delivers the mixture into the engine. A spark or flame inside the engine ignites the mixture. This is the function of the carburetor in today's automobiles. By comparison, the hot bulb engine sprayed gasoline onto a hot surface next to the cylinder, and then drew the evaporating fuel into the engine in vapor form. With the hot bulb engine it was possible to use less volatile fuels such as kerosene. A third method is the diesel compression engine. Rather than using an external heat source to ignite the gas, as in the first two methods, German engineer Rudolf Diesel (1858-1913) invented a process in which the gas ignites itself. Diesel had a strong background in math and science, and he knew that when a gas is compressed, its temperature increases to the point where the fuel ignites.

Impact

By the turn of the century, internal combustion engines had become integral to Western life. Industrial plants throughout Europe and America used them extensively, and the gateway for the large-scale automobile production of the 1900s opened.

In the area of transportation, the gasoline internal combustion engine and its variants (primarily the diesel engine) have been adapted for use in travel by sea, land, and air. At sea, a great number of smaller ships were, and continue to be, powered by diesel engines, speeding the movement of people and goods between any places connected by water. This has served to make trade more rapid and less expensive. Combining sea transportation with more efficient land transportation of goods makes these advantages even more significant. In turn, enhancing trade tends to lead to greater prosperity and a higher standard of living for both parties, not to mention the formation of new jobs.

Airplanes also owe their existence to the development of the gasoline engine. Many inventors had attempted powered flight at the end of the nineteenth century, but it wasn't until low-weight, high-output gasoline engines were available that the field of aviation was established. In fact, gasoline engines dominated aviation for the first half of the twentieth century and even today play an important role in private, commercial, and military aviation.

Also to be considered is the impact on farming and food production. Tractors and other modern farming equipment, usually running on diesel or gasoline engines, play a significant role in the abundance of food in the developed world and in parts of the developing world. The use of tractors to till, plant, and harvest as well as to pull heavy loads has helped to increase the amount of land a single farmer can work, as well as increasing the yield per hectare. This dual increase in the efficiency of individual farmers results in more food at lower prices. In the developed world this means not only more and cheaper food available for its citizens, but more food available for export to all nations.

The diesel engine is an outgrowth of the internal combustion engine, as mentioned previously. Diesel engines are powerful, require less maintenance, and use less highly refined fuel than gasoline engines. These factors make them less expensive, and they have become the engine of choice for rail travel, large boats and small ships, and trucks. Diesel engines are also widely used for electrical power generation, especially as emergency backup power supplies for installations such as hospitals and nuclear power plants. In both capacities, diesel engines have proven themselves dependable and inexpensive to maintain and operate.

The final impact that must be discussed is the environmental impact of the internal combustion engine. All internal combustion engines operate by burning some form of hydrocarbon and discharging exhaust gases. These hydrocarbons are typically derived from petroleum, and they burn to form carbon dioxide, carbon monoxide, and water. Although hydrogen engines have been developed that burn hydrogen and produce water vapor as an exhaust gas, they are uncommon as of this writing.

From the perspective of fuel, petroleum reserves are finite and are becoming ever-more difficult to discover and extract. The process of extraction invariably results in some environmental impact, not only at the drilling site, but along the transportation route. Since most petroleum is recovered in regions distant from refineries and industrial nations, much of it is transported by ocean-going tanker ships which sometimes cause spills with potentially serious results.

Once burned in engines, hydrocarbon fuels release many gases, most of which have contributed to air pollution. Until banned in the United States, many fuels also contained lead compounds, which were implicated in cases of lead poisoning. Even without lead, however, carbon dioxide, the primary combustion exhaust gas, seems to be produced in sufficiently high quantities that atmospheric levels have been noted to be increasing globally. Since carbon dioxide is known to help trap solar heat, there is a great deal of speculation that widespread use of internal combustion engines is causing temperatures to rise worldwide with potentially catastrophic results. However, it must be stressed that data that have been interpreted to show global warming are subject to many different readings, and not all scientists believe that global warming is actually occurring. In addition, it must be remembered that, for most of the history of the Earth, temperatures have been much higher than at present. So, even if global warming is occurring, it may or may not be due to burning fossil fuels in internal-combustion engines.

TODD JENSEN AND P. ANDREW KARAM