Internal Combustion Engine
James Watt’s discovery of the steam engine is considered the beginning of the Industrial Revolution. Prior to this, mechanical power relied on human labor, making it expensive and inefficient. Following this development in England during the second half of the 18th century, industrialization based on engine power rapidly expanded.
James Watt developed the steam engine while seeking an effective means to pump water out of mines.
In the late 12th and early 13th centuries, the scholar al-Jazari, who lived in Diyarbakır and Cizre, designed five devices to lift large quantities of water. Three of these devices operated using water power, while two were automatic, meaning they functioned on their own. During these works, al-Jazari used the crankshaft for the first time in history. The device that converts rotary motion into linear motion is regarded as one of the most important inventions in history and is now used in countless applications, from automobiles to locomotives.
In al-Jazari’s water-powered pump mechanism, gear wheels, copper pistons, suction and delivery pipes, and one-way flap valves were employed. This device could lift water approximately twelve meters upward.
When the water current turns the water wheel, the water wheel shaft rotates. This rotation is transferred via a linkage to another wheel attached to the crankshaft. The crankshaft, connected to the central axis, converts rotational motion into linear motion. One of the two pistons attached to the crankshaft draws water into its chamber, while the other piston forces the water out through a discharge pipe. The water is then channeled to a storage tank for use.
Another scholar known for his work on lifting water is the 16th-century Ottoman engineer Taqi al-Din. One of his designs was a two-cylinder pump, and another was a six-cylinder pump.
In the six-cylinder pump, a water wheel is attached to a horizontal shaft (called a camshaft). When the water current turns the water wheel, the camshaft rotates. Each cam on the camshaft pushes down a connecting rod. All connecting rods are arranged to converge at a central axis. At the other end of each connecting rod is a lead weight that pulls the piston upward when it rises. During this motion, water is drawn into the piston cylinder due to the vacuum created inside. Once the cam rotates past a certain angle, it releases the connecting rod, completing one stroke of the piston. As the lead weight descends under gravity, a valve at the intake side of the cylinder closes, and the water is pumped upward through the discharge pipe.
An apparatus consisting of a metallic cylinder with a piston inside, considered a precursor to internal combustion engines, was developed in 1673 in the Netherlands by physicist Christiaan Huygens and his assistant Denis Papin. Huygens, inspired by the vacuum pump principle developed by German Otto von Guericke, used the combustion of gunpowder rather than an air pump to create a vacuum. This vacuum returns the piston to its initial position, thereby creating a power stroke.
Swiss inventor François Isaac de Rivaz contributed to the development of the automobile around the 1770s. Although his numerous steam-powered vehicles lacked flexibility and were impractical, he patented a device in 1807 that resembled an internal combustion engine, inspired by the operation of a voltaic pistol.
Belgian Émile Lenoir patented a two-stroke internal combustion engine under the name “Gas and Expanding Air Engine” in 1859, and in 1860 he developed the first internal combustion engine ignited by electric spark and cooled by water.
Lenoir believed that the steam engine had reached the end of its useful life after 100 years of development and could no longer be significantly improved, so he turned his efforts toward internal combustion processes. In steam engines, converting fuel energy into mechanical work takes considerable time: the fuel must first be burned outside the cylinder, generating steam, which is then fed into the cylinder to exert force on the piston. According to Lenoir’s theory, burning the fuel directly inside the cylinder would be more efficient, allowing energy to be transferred directly to the piston without losses. Instead of coal, gas was used as fuel. The gas would be introduced into the cylinder, ignited, and directly drive the piston. In 1858, Lenoir successfully designed his engine as a two-stroke gas engine.
The operating principle of the steam engine is evident in the Lenoir engine. Lenoir intended to manufacture and sell this engine himself, so in 1859 he founded the company Société des Moteurs Lenoir in Paris. From 1860 onward, this company produced approximately 330 Lenoir engines. It can be said that the Lenoir engine was easier and safer to use than the steam engine. The Lenoir engine was the first internal combustion engine used in air transportation. In 1872, German engineer Paul Haenlein tested the Lenoir gas engine in a 50-meter-long air vehicle he named “Aeolus.” During tests, the vehicle reached a height of 20 meters and achieved a speed of 18 km/h.
During tests, the vehicle reached a height of 20 meters and achieved a speed of 18 km/h. The Lenoir engine had two disadvantages: because the fuel-air mixture was not compressed, its efficiency was very low.
Additionally, since combustion occurred on both sides of the piston, the piston overheated rapidly, greatly increasing the risk of seizure. As a result, the engine required excessive fuel and lubricating oil due to high friction. Despite these disadvantages, the Lenoir engine remains a significant milestone in the development of internal combustion engines. In fact, the Lenoir engine served as the inspiration for modern gasoline, diesel, and gas engines.
Lenoir Engine and Otto Engine
In the 1850s, Nikolaus August Otto recognized the industry’s need for a more practical engine and was strongly influenced by Lenoir’s invention of the gas engine. To improve the technology and design, in 1861 he built a working model in his small workshop in Cologne. The internal explosions caused by combustion damaged the machine. After numerous failed experiments exhausted his financial resources, Otto was on the verge of giving up when he met the financially capable engineer Eugen Langen, and together they founded the company “N. A. Otto & Cie” in 1864.
This company focused on manufacturing internal combustion engines. Through research, they achieved smooth operation of the gas engine. The new engine was awarded a prize at the 1867 International Exposition in Paris. Its most important feature was that it consumed only one-third of the fuel required by the Lenoir engine.
This engine became historically significant as the world’s first non-impact, non-pressurized gas engine. In brief, its operating principle involved the combustion of the gas-air mixture beneath the cylinder, causing the piston to move upward abruptly. This motion turned a rack-and-pinion gear connected to the crankshaft. As a vacuum formed beneath the piston, atmospheric pressure pushed the piston downward.
Otto believed that the engine’s purpose should be to provide motion for people on land, water, and in the air. James Watt’s steam engine had been used for 100 years in railways, mines, and industry, but due to its large size, weight, and crude design, it was not preferred as a propulsion system in vehicles. Otto regarded the Lenoir engine as a crucial foundation for his own design and, after conducting experiments and modifications on it, discovered the four-stroke principle (intake-compression-power-exhaust). This engine became known worldwide as the “Atmospheric Otto Gas Engine.”
Alphonse Beau de Rochas improved this principle by developing a four-stroke thermodynamic cycle consisting of intake, compression, combustion, and exhaust. As a theorist, Beau de Rochas could not implement his ideas in practice. He patented the concept in 1862 but could not protect it due to financial difficulties. The theoretical foundation laid by Beau de Rochas enabled the practical utilization of internal combustion engines.
Nikolaus Otto became the first engineer in 1872 to implement Beau de Rochas’s principle, and this cycle began to be known as the “Otto Cycle.” In 1877, a gas engine factory named “Gasmotorenfabrik Deutz AG” was established in the Deutz district of Cologne. The company’s name later became “Klöckner-Humboldt-Deutz AG.” At this factory, Otto employed Daimler as a sales representative, Maybach as chief designer, and Langen as a member of the board of directors. Within ten years, 2,640 engines were sold.
In 1877, Otto failed in his attempts to transition from gas fuel to liquid fuel using heating tubes and electric ignition. However, in 1884 he successfully built the first engine to operate on liquid fuel. Otto’s invention of the air-fuel mixture and ignition system was superior and more reliable than other systems. Deutz did not patent this system, so Robert Bosch was able to manufacture and develop it without restriction. This new magneto-electric ignition system was Robert Bosch’s first major success. Otto’s 25-year dream of the internal combustion engine was finally realized. Since their healthy emergence in 1875, internal combustion engines have been continuously developed and produced for 140 years.
