Otto engine was a large stationary single-cylinder internal
combustion four-stroke engine designed by Nikolaus Otto. It was a
low-RPM machine, and only fired every other stroke due to the Otto
cycle, also designed by Otto.
3 Atmospheric engine
4 The Otto cycle
Carburetor and low voltage Ignition
4.2 Loss of a patent
5 Stationary engines
Spark plug firing
5.2 Engine speed regulation
5.3 Cylinder cooling
6 First use in transportation
8 External links
Three types of internal combustion engines were designed by German
Nikolaus Otto and his partner Eugen Langen. The models were
a failed 1862 compression engine, an 1864 atmospheric engine, and the
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
Otto engine for transportation use.
The 1860 Lenoir Engine
Nikolaus August Otto as a young blood 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
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
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).
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.
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.
The original Otto atmospheric engine running on Youtube
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
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. 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.
For all its commercial success, with the company producing 634 engines
a year by 1875, 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. 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.
The Otto cycle
Otto engine with slide valve ignition
A 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. 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.
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.
The Otto Cycle engine was eventually adopted to run on
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
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.
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,
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. Note that no fuel is used on the mis-fire strokes.
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
First use in transportation
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.  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. 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. 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. The Daimler/Maybach
Reitwagen reproduction being run
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 gasoline
^ a b , Nikolaus August Otto: Inventor Of The Internal Combustion
^ a b , The History of Daimler-Benz.
^  The
Daimler-Benz Museum, Cannstatt, Germany.
^ a b c d e "Archived copy". Archived from the original on 2011-05-07.
Retrieved 2011-05-22. , NA Otto Museum.
^ , Deutz AG.
^ Wise, David Burgess. "Daimler: Founder of the Four-Wheeler", in
Northey, Tom, ed. World of Automobiles (London: Orbis, 1974), Volume
^ a b c d e Wise, p.482.
^ Otto Museum Website Archived 2011-05-07 at the Wayback Machine.
Wikimedia Commons has media related to Otto engines.
Photograph of Jean Joseph Etienne Lenoir
Encyclopædia Britannica article on Etienne Lenoir
Thinkquest Otto Engine
Photograph of Nikolaus August Otto