Otto engine

Last updated
This is a video montage of the Otto engines running at the Western Minnesota Steam Threshers Reunion (WMSTR), in Rollag, Minnesota. (2min 16sec, 320x240, 340kbit/s video)

The Otto engine was a large stationary single-cylinder internal combustion four-stroke engine designed by the German Nicolaus Otto. It was a low-RPM machine, and only fired every other stroke due to the Otto cycle, also designed by Otto.



Three types of internal combustion engines were designed by German inventors Nicolaus Otto and his partner Eugen Langen. The models were a failed 1862 compression engine, an 1864 atmospheric engine, and the 1876 Otto cycle engine known today as the gasoline engine. The engines were initially used for stationary installations, as Otto had no interest in transportation. Other makers such as Daimler perfected the Otto engine for transportation use. [1] [2] [3]


The 1860 Lenoir Engine Lenoirmotor.jpg
The 1860 Lenoir Engine

Nicolaus August Otto as a young man was a traveling salesman for a grocery concern. In his travels he encountered the internal combustion engine built in Paris by Belgian expatriate Jean Joseph Etienne Lenoir. In 1860 Lenoir succeeded in creating a double-acting engine which ran on illuminating gas at 4% efficiency. The 18 liter Lenoir engine was able to produce only 2 horsepower.

In testing a replica of the Lenoir engine in 1861 Otto became aware of the effects of compression on the fuel charge. In 1862 Otto attempted to produce an engine to improve on the poor efficiency and reliability of the Lenoir engine. He tried to create an engine which would compress the fuel mixture prior to ignition, but failed, as that engine would run no more than a few minutes prior to its destruction. Many engineers were also trying to solve the problem with no success. [4]

In 1864 Otto and Eugen Langen founded the first internal combustion engine production company NA Otto and Cie (NA Otto and Company). Otto and Cie succeeded in creating a successful atmospheric engine that same year. [4]

The factory ran out of space and was moved to the town of Deutz, Germany in 1869 where the company was renamed to Gasmotoren-Fabrik Deutz (The Gas Engine Manufacturing Company Deutz). [4]

Gottlieb Daimler was technical director and Wilhelm Maybach was the head of engine design. Daimler was a gunsmith who had also worked on the Lenoir engine previously. [5]

The Otto/Langen atmospheric engine of 1867 Enginy Otto-langen 1867.jpg
The Otto/Langen atmospheric engine of 1867

By 1876 Otto and Langen succeeded in creating the first internal combustion engine that compressed the fuel mixture prior to combustion for far higher efficiency than any engine created to this time.

Atmospheric engine

The first version of the atmospheric engine used a fluted column design which was the design of Eugen Langen. The atmospheric engine has its power stroke delivered upward using a rack and pinion to convert the piston's linear motion to rotary motion. The expansion ratio of this engine was much more effective than that of the 1860 Lenoir engine and gave the engine its superior efficiency.

The Lenoir engine was an engine that burned fuel without first trying to compress the fuel/mixture. The Otto/Langen atmospheric engine ran at 12% efficiency and produced .5  hp (0.37  kW ; 0.51  PS ) at 80 RPM. In competition at the 1867 World's Fair in Paris, it easily bested the efficiency of the Lenoir engine and won the gold medal, thus paving the way for production and sales which funded additional research.

The first version used a frame to stabilize the rack. This was soon dispensed with as the design was simplified. Later engines dispensed with the fluted cylinder as well. The atmospheric engine used a gas flame ignition system and was made in output sizes from 0.25 to 3  hp (0.19 to 2.24  kW ; 0.25 to 3.04  PS ).

When in 1872 N.A. Otto & Cie reorganized as Gasmotoren-Fabrik Deutz, management picked Daimler as factory manager, bypassing even Otto, and Daimler joined the company in August, taking Maybach with him as chief designer. [6] While Daimler managed to improve production, the weakness in the Otto's vertical piston design, coupled to Daimler's stubborn insistence on atmospheric engines, led the company to an impasse. [7]

For all its commercial success, with the company producing 634 engines a year by 1875, [7] the Otto and Langen engine had hit a technical dead end: it produced only 3  hp (2.2  kW ; 3.0  PS ), yet required 10–13 ft (3.0–4.0 m) headroom to operate. [7] In 1882, after producing 2,649 engines, the atmospheric engine production was discontinued. This was also the year that Gottlieb Daimler and Wilhelm Maybach left the company. [4]

The Otto cycle

An 1880s era American Otto engine for stationary use PSM V18 D500 An american internal combustion otto engine.jpg
An 1880s era American Otto engine for stationary use

After 14 years of research and development Otto succeeded in creating the compressed charge internal combustion engine May 9, 1876. Otto found a way to layer the fuel mixture into the cylinder to cause the fuel to burn in a progressive, as opposed to explosive fashion. He referred to this as being a layered or stratified charge. This resulted in controlled combustion and a longer push of the piston in the cylinder rather than the explosion which destroyed all the engines attempted previously. The fuel was still illuminating gas just as Lenoir's and his own atmospheric engines had used.

This engine used four cycles in its creation of power. It is known now as the Otto Cycle engine. This is the same engine that was first attempted in 1862.

Otto turned his attention to the 4-stroke cycle largely due to the efforts of Franz Rings and Herman Schumm, brought into the company by Gottlieb Daimler. [7] It is this engine (the Otto Silent Engine), and not the Otto & Langen engine, to which the Otto cycle refers. This was the first commercially successful engine to use in-cylinder compression (as patented by William Barnett in 1838). The Rings-Schumm engine appeared in autumn 1876 and was immediately successful. [7]

The cylinder arrangement of the compression engine was horizontal. It featured a slider valve control with gas flame ignition, which overcame the problems that Lenoir could not overcome with electric ignition which was unreliable at that time. In the 15 years prior to the development of the Otto engine power output never exceeded 3 hp. In a few years after the Otto engine was developed engine power rose until it reached 1000 hp. [4]

The Otto Cycle engine was eventually adopted to run on Ligroin and eventually gasoline, and many gases. During WWII Otto engines were run on more than 62 different fuels, such as wood gas, coal gas, propane, hydrogen, benzene, and many more. The engine is limited to light fuels. A later development of this engine, known as the Diesel engine, can burn heavy fuels and oils.

Carburetor and low voltage Ignition

Deutz also developed the carburetor and a reliable low voltage ignition system in 1884. This allowed the use of liquid petroleum fuel for the first time and made the use of the engine in transportation feasible. This work was conducted in parallel to the work of Gottlieb Daimler and Wilhelm Maybach who also developed a carburetor which replaced the original hot tube ignition on the Daimler Reitwagen, and a magneto ignition system which formed the basis of the magneto of the Robert Bosch Corporation. Daimler continued the development of Otto's engine for transportation while Deutz switched to Diesel engines.

Loss of a patent

In 1886, the German patent office nullified the Deutz patent that would have run until 1891 due to the discovery of a previous patent for a four cycle engine by Frenchman Alphonse Beau de Rochas. Deutz was unable to show that his stratified charge induction system was unlike that described in the Rochas patent and lost his monopoly and 1 of his 25 patents. By 1889 more than 50 companies were manufacturing Otto design engines. [8]

Stationary engines

Spark plug firing

Otto engines were equipped with a number of different mechanism designs to trigger sparking. The Otto is one of the first engines to use a spark plug, which is a device that produces a small electric spark to ignite the fuel charge. This usually consisted of a pivoting trip-arm that briefly grabs a power switch lever and gives it a quick pull. The switch lever is then released and allowed to snap back to its original position in preparation for the next cycle. This system requires an external electric battery, ignition coil, and electric charging system similar to modern automobile engines.

Later Otto engines employed a small magneto directly on the engine. Rather than tripping a switch, the spark plug firing arm applies a quick rotation to the magneto rotor, which then snaps back under spring tension. This quick rotation of the magneto coil produces a very brief current flow that fires the spark plug and ignites the fuel. This design has the advantage of requiring no external battery, and is how modern portable gas engines operate, incorporating the magnet portion of the magneto into the flywheel. Modern portable engines excite the magneto with every flywheel rotation, and so use a cam-operated electric switch to prevent plug firing except for the power stroke of the engine (see wasted spark).

Engine speed regulation

How the governor regulates engine speed on an Otto engine. This particular engine operates on natural gas; the large disk-shaped object below the engine is the gas pressure regulator. (22sec, 320x240, 320kbit/s video)
Close-up view of the governor wheel either riding up over the fuel intake cam or sliding to the right and coasting. (14sec, 320x240, 250kbit/s video)

This is a demonstration of how the speed regulation works in the Otto engine. The spinning balls are the centrifugal governor, and as the machine runs slower the small wheel moves to the left, inserting the rod into the nearby roller and pushing it up to trigger the intake of fuel to fire the engine for one revolution.

If the machine is under load and still running too slowly, the cam continues to stay inserted and makes the engine fire repeatedly for each ignition cycle. When the engine speed increases, the governor pulls the small wheel to the right and the machine coasts without injecting any fuel, though the spark plug continues to fire with no fuel in the cylinder.

This method of speed-control is often referred to as the Hit or Miss method because the engine mis-fires (for lack of fuel-mixture) on those power-strokes where the engine is running faster than the governed speed, but will hit (fire) on power strokes where the speed is too low. No fuel is used on the mis-fire strokes.

Cylinder cooling

Otto engines use a flowing water jacket around the cylinder wall, similar to modern engine cooling systems. The stationary Otto engines on display at the Western Minnesota Steam Threshers Reunion all share a single large heat radiator outside the building. This centralized distant heat dissipation system also helps to keep the engine building cool.

First use in transportation

1885 Daimler's Petroleum Reitwagen Daimler Reitwagen.JPG
1885 Daimler's Petroleum Reitwagen

Otto and his manager Gottlieb Daimler had a major disagreement on the future direction of the Otto engine. While Otto wanted to produce large engines for stationary applications Daimler wanted to produce engines small enough to be used in transportation. After a period of disagreement Daimler left Otto's employ and took Wilhelm Maybach with him. In 1883 Daimler and Maybach created a .5 hp engine that was small and efficient. In order to evade the patents that Otto held on the engine design, a pretense was found concerning a patent issued to Beau De Rochas in 1862, the same year that Otto failed to create his four cycle engine the first time. Those who were jealous of the Otto patents (there were 25 patents) had 1 patent overturned in Germany largely because the court failed to understand the significance of Otto's layered charge system which overcame the problems of explosive combustion which destroyed all engine designs previously.

Daimler always referred to his design as an explosion engine, to contrast it against Otto's engine and was able to evade paying royalties to Otto. In 1885 he and Maybach created an engine called the "Grandfather Clock" engine and built a two-wheeled frame around it. This became the first Otto engined vehicle. Daimler's fourteen-year-old son Adolf was the first person to ride on this motorized bicycle which is the first internal combustion engined motor vehicle. The 1885 Daimler/Maybach Petroleum Reitwagen (Riding Car) was the first motorcycle (and the first motor vehicle) using an internal combustion engine. [2] While Deutz continued to produce large stationary engines Daimler moved onto boats, airships, locomotives, automobiles, trucks, and other transportation uses. Deutz is the world's oldest engine producer. [1] Daimler, which became Daimler-Benz, is the world's oldest automobile manufacturer.

Daimler-Benz produced this video for the 125th anniversary of the creation of the first motor vehicle which Daimler called the "Petroleum Reitwagen." It used a hot tube ignition specifically because the electrical systems of that era were unreliable. This engine ran on the fuel Ligroin, as did all vehicles until well past the year 1905.[ citation needed ] Daimler and Maybach founded a company known as Daimler Motorenwerke Gesellschaft which later merged with Benz to form Daimler-Benz, known also as Mercedes-Benz.

Today Otto's company Deutz is one of the largest makers of heavy duty vehicles in the world. Daimler-Benz is one of the largest and most respected makers of luxury automobiles in the world. Virtually all of the world's makers of automobiles produce vehicles using Otto cycle engines which are so ubiquitous as to be referred to as internal-combustion engines, gasoline engines, and spark-ignition engines.

Related Research Articles

<span class="mw-page-title-main">Diesel engine</span> Type of internal combustion engine

The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-called compression-ignition engine. This contrasts with engines using spark plug-ignition of the air-fuel mixture, such as a petrol engine or a gas engine.

Timeline of motor and engine technology

Miller cycle Thermodynamic cycle

In engineering, the Miller cycle is a thermodynamic cycle used in a type of internal combustion engine. The Miller cycle was patented by Ralph Miller, an American engineer, U.S. Patent 2,817,322 dated Dec 24, 1957. The engine may be two- or four-stroke and may be run on diesel fuel, gases, or dual fuel.

Wilhelm Maybach German businessman

Wilhelm Maybach was an early German engine designer and industrialist. During the 1890s he was hailed in France, then the world centre for car production, as the "King of Designers".

Petrol engine Internal combustion engine designed to run on gasoline

A petrol engine is an internal combustion engine designed to run on petrol (gasoline). Petrol engines can often be adapted to also run on fuels such as liquefied petroleum gas and ethanol blends.

<span class="mw-page-title-main">Four-stroke engine</span> Internal combustion engine type

A four-strokeengine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed:

  1. Intake: Also known as induction or suction. This stroke of the piston begins at top dead center (T.D.C.) and ends at bottom dead center (B.D.C.). In this stroke the intake valve must be in the open position while the piston pulls an air-fuel mixture into the cylinder by producing vacuum pressure into the cylinder through its downward motion. The piston is moving down as air is being sucked in by the downward motion against the piston.
  2. Compression: This stroke begins at B.D.C, or just at the end of the suction stroke, and ends at T.D.C. In this stroke the piston compresses the air-fuel mixture in preparation for ignition during the power stroke (below). Both the intake and exhaust valves are closed during this stage.
  3. Combustion: Also known as power or ignition. This is the start of the second revolution of the four stroke cycle. At this point the crankshaft has completed a full 360 degree revolution. While the piston is at T.D.C. the compressed air-fuel mixture is ignited by a spark plug or by heat generated by high compression, forcefully returning the piston to B.D.C. This stroke produces mechanical work from the engine to turn the crankshaft.
  4. Exhaust: Also known as outlet. During the exhaust stroke, the piston, once again, returns from B.D.C. to T.D.C. while the exhaust valve is open. This action expels the spent air-fuel mixture through the exhaust valve.
Gottlieb Daimler German businessman

Gottlieb Wilhelm Daimler was a German engineer, industrial designer and industrialist born in Schorndorf, in what is now Germany. He was a pioneer of internal-combustion engines and automobile development. He invented the high-speed liquid petroleum-fueled engine.

<span class="mw-page-title-main">Nicolaus Otto</span> German inventor

Nicolaus August Otto was a German engineer who successfully developed the compressed charge internal combustion engine which ran on petroleum gas and led to the modern internal combustion engine. The Association of German Engineers (VDI) created DIN standard 1940 which says "Otto Engine: internal combustion engine in which the ignition of the compressed fuel-air mixture is initiated by a timed spark", which has been applied to all engines of this type since.

William Hall Barnett, is described as a 'founder' in his 1836 patent, and an 'ironfounder' in his 1838 patent, and later as an engineer and gas engineer, working in Brighton, UK. He worked for many years for the Brighton and Hove General Gas Company.

<span class="mw-page-title-main">Deutz AG</span> German motor manufacturer

Deutz AG is a German internal combustion engine manufacturer, based in Porz, Cologne, Germany.

Dugald Clerk Scottish engineer (1854–1932)

Sir Dugald Clerk KBE, LLD FRS was a Scottish engineer who designed the world's first successful two-stroke engine in 1878 and patented it in England in 1881. He was a graduate of Anderson's University in Glasgow, and Yorkshire College, Leeds. He formed the intellectual property firm with George Croydon Marks, called Marks & Clerk. He was knighted on 24 August 1917.

Daimler-Motoren-Gesellschaft was a German engineering company and later automobile manufacturer, in operation from 1890 until 1926. Founded by Gottlieb Daimler (1834–1900) and Wilhelm Maybach (1846–1929), it was based first in Cannstatt. Daimler died in 1900, and their business moved in 1903 to Stuttgart-Untertürkheim after the original factory was destroyed by fire, and again to Berlin in 1922. Other factories were located in Marienfelde and Sindelfingen.

Gas engine

A gas engine is an internal combustion engine that runs on a gaseous fuel, such as coal gas, producer gas, biogas, landfill gas or natural gas. In the United Kingdom, the term is unambiguous. In the United States, due to the widespread use of "gas" as an abbreviation for gasoline (petrol), such an engine might also be called a gaseous-fueled engine or natural gas engine or spark ignited.

George Brayton American mechanical engineer and inventor

George Bailey Brayton was an American mechanical engineer and inventor. He was noted for introducing the constant pressure engine that is the basis for the gas turbine, and which is now referred to as the Brayton cycle.

<span class="mw-page-title-main">Benz Patent-Motorwagen</span> Vehicle widely regarded as the first automobile

The Benz Patent-Motorwagen, built in 1885 by the German Carl Benz, is widely regarded as the world's first practical automobile, a self-propelled vehicle for carrying people, and first car put into series production. It was patented and unveiled in 1886. The original cost of the vehicle in 1886 was 600 imperial German marks, approximately 150 US dollars.

<span class="mw-page-title-main">Hit-and-miss engine</span>

A hit-and-miss engine or Hit 'N' Miss is a type of stationary internal combustion engine that is controlled by a governor to only fire at a set speed. They are usually 4-stroke but 2-stroke versions were made. It was conceived in the late 19th century and produced by various companies from the 1890s through approximately the 1940s. The name comes from the speed control on these engines: they fire ("hit") only when operating at or below a set speed, and cycle without firing ("miss") when they exceed their set speed. This is as compared to the "throttle governed" method of speed control. The sound made when the engine is running without a load is a distinctive "Snort POP whoosh whoosh whoosh whoosh snort POP" as the engine fires and then coasts until the speed decreases and it fires again to maintain its average speed. The snorting is caused by the atmospheric intake valve used on many of these engines.

The Daimler Motorized Carriage was the first car produced by German engineers Gottlieb Daimler and Wilhelm Maybach, who founded Daimler Motoren Gesellschaft (DMG). The first car was sold in 1892.

<span class="mw-page-title-main">History of the internal combustion engine</span> Aspect of history

Various scientists and engineers contributed to the development of internal combustion engines. In 1791, the English inventor John Barber patented a gas turbine. In 1794 Thomas Mead patented a gas engine. Also in 1794 Robert Street patented an internal-combustion engine, which was also the first to use liquid fuel (petroleum) and built an engine around that time. In 1798, John Stevens designed the first American internal combustion engine. In 1807, French engineers Nicéphore and Claude Niépce ran a prototype internal combustion engine, using controlled dust explosions, the Pyréolophore. This engine powered a boat on the Saône river, France. The same year, the Swiss engineer François Isaac de Rivaz built and patented a hydrogen and oxygen powered internal-combustion engine. The fuel was stored in a balloon and the spark was electrically ignited by a hand-operated trigger. Fitted to a crude four-wheeled wagon, François Isaac de Rivaz first drove it 100 meters in 1813, thus making history as the first car-like vehicle known to have been powered by an internal-combustion engine. In 1823, Samuel Brown patented the first internal combustion engine to be applied industrially in the U.S.; one of his engines pumped water on the Croydon Canal from 1830 to 1836. He also demonstrated a boat using his engine on the Thames in 1827, and an engine-driven carriage in 1828. Father Eugenio Barsanti, an Italian engineer, together with Felice Matteucci of Florence invented the first real internal combustion engine in 1853. Their patent request was granted in London on June 12, 1854, and published in London's Morning Journal under the title "Specification of Eugene Barsanti and Felix Matteucci, Obtaining Motive Power by the Explosion of Gasses". In 1860, Belgian Jean Joseph Etienne Lenoir produced a gas-fired internal combustion engine. In 1864, Nicolaus Otto patented the first atmospheric gas engine. In 1872, American George Brayton invented the first commercial liquid-fueled internal combustion engine. In 1876, Nicolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, four-stroke cycle engine. In 1879, Karl Benz patented a reliable two-stroke gas engine. In 1892, Rudolf Diesel developed the first compressed charge, compression ignition engine. In 1926, Robert Goddard launched the first liquid-fueled rocket. In 1939, the Heinkel He 178 became the world's first jet aircraft. In 1954 German engineer Felix Wankel patented a "pistonless" engine using an eccentric rotary design.

Daimler <i>Reitwagen</i> First motorcycle, 1885

The Daimler Reitwagen or Einspur was a motor vehicle made by Gottlieb Daimler and Wilhelm Maybach in 1885. It is widely recognized as the first motorcycle. Daimler is often called "the father of the motorcycle" for this invention. Even when the steam powered two-wheelers that preceded the Reitwagen, the Michaux-Perreaux and Roper of 1867–1869, and the 1884 Copeland, are considered motorcycles, it remains nonetheless the first gasoline internal combustion motorcycle, and the forerunner of all vehicles, land, sea and air, that use its overwhelmingly popular engine type.

<span class="mw-page-title-main">Internal combustion engine</span> Engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber

An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to. This replaced the external combustion engine for applications where the weight or size of an engine was more important.


  1. 1 2 , Nikolaus August Otto: Inventor Of The Internal Combustion Engine.
  2. 1 2 Archived 2016-03-03 at the Wayback Machine , The History of Daimler-Benz.
  3. Archived 2012-05-10 at the Wayback Machine The Daimler-Benz Museum, Cannstatt, Germany.
  4. 1 2 3 4 5 "125 Jahre Viertaktmotor | Oldtimer Club Nicolaus August Otto e.V." Archived from the original on 2011-05-07. Retrieved 2011-05-22., NA Otto Museum.
  5. Archived 2011-02-17 at the Wayback Machine , Deutz AG.
  6. Wise, David Burgess. "Daimler: Founder of the Four-Wheeler", in Northey, Tom, ed. World of Automobiles (London: Orbis, 1974), Volume 5, p.482.
  7. 1 2 3 4 5 Wise, p.482.
  8. Otto Museum Website Archived 2011-05-07 at the Wayback Machine