![Boxerengineanimation](https://upload.wikimedia.org/wikipedia/commons/8/8a/Boxerengineanimation.gif)
A flat engine is a
piston engine where the cylinders are located on either side of a central
crankshaft. Flat engines are also known as horizontally opposed engines, however this is distinct from the less common
opposed-piston engine design, whereby each cylinder has two pistons sharing a central combustion chamber.
The most common configuration of flat engines is the
boxer engine
A flat engine is a piston engine where the cylinders are located on either side of a central crankshaft. Flat engines are also known as horizontally opposed engines, however this is distinct from the less common opposed-piston engine design, wh ...
configuration, in which the pistons of each opposed pair of cylinders move inwards and outwards at the same time. The other configuration is effectively a
V engine
A V engine, sometimes called a Vee engine, is a common configuration for internal combustion engines. It consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common crankshaft. These cylinder ...
with a 180-degree angle between the cylinder banks; in this configuration each pair of cylinders shares a single crankpin, so that as one piston moves inward, the other moves outward.
The first flat engine was built in 1897 by
Karl Benz
Carl Friedrich Benz (; 25 November 1844 – 4 April 1929), sometimes also Karl Friedrich Benz, was a German engine designer and automotive engineer. His Benz Patent Motorcar from 1885 is considered the first practical modern automobile and fir ...
. Flat engines have been used in aviation, motorcycle and automobile applications. They are now less common in cars than
straight engines (for engines with less than six cylinders) and
V engine
A V engine, sometimes called a Vee engine, is a common configuration for internal combustion engines. It consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common crankshaft. These cylinder ...
s (for engines with six or more cylinders). Flat engines are more common in aircraft, where straight engines are a rarity and V engines have almost vanished except in historical aircraft. They have even replaced
radial engines
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is cal ...
in many smaller installations.
Design
![Moteurs à Plat - V à 180° vs](https://upload.wikimedia.org/wikipedia/commons/7/7a/Moteurs_%C3%A0_Plat_-_V_%C3%A0_180%C2%B0_vs._Boxer.png)
The advantages of flat engines are a short length, low
centre of mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
and suitability for
air cooling.
Compared with the more common
straight engines, flat engines have better
primary balance
Engine balance refers to how the forces (resulting from combustion or rotating/reciprocating components) are balanced within an internal combustion engine or steam engine. The most commonly used terms are ''primary balance'' and ''secondary bala ...
(resulting in less vibration); however the disadvantages are increased width and the need to have two cylinder heads. Compared with
V engine
A V engine, sometimes called a Vee engine, is a common configuration for internal combustion engines. It consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common crankshaft. These cylinder ...
s— the most common layout for engines with six cylinders or more— flat engines have a lower centre of mass (and a better primary balance than V6 engines), however they usually have a larger width.
The most common usages of flat engines are:
*
Flat-twin engine
A flat-twin engine is a two-cylinder internal combustion engine with the cylinders on opposite sides of the crankshaft. The most common type of flat-twin engine is the boxer-twin engine, where both pistons move inwards and outwards at the same ti ...
s are mostly used in motorcycles. Occasionally been used in light cars, aircraft and industrial applications, mostly up until the 1960s.
*
Flat-four engines are mostly used in cars (particularly in the earlier
Volkswagen
Volkswagen (),English: , . abbreviated as VW (), is a German Automotive industry, motor vehicle manufacturer headquartered in Wolfsburg, Lower Saxony, Germany. Founded in 1937 by the German Labour Front under the Nazi Party and revived into a ...
Type 1 to
4 and by
Subaru in most of their models), and have occasionally been used in motorcycles. Their most common use is in smaller single-engine
general aviation
General aviation (GA) is defined by the International Civil Aviation Organization (ICAO) as all civil aviation aircraft operations with the exception of commercial air transport or aerial work, which is defined as specialized aviation services ...
aircraft in which they are still manufactured and used to this day.
*
Flat-six engine
A flat-six engine, also known as a horizontally opposed-six, is a six-cylinder piston engine with three cylinders on each side of a central crankshaft. The most common type of flat-six engine is the boxer-six engine, where each pair of opposed cy ...
s are mostly used in cars (particularly by the
Porsche 911 sports car), and have occasionally been used in motorcycles and aircraft.
*
Flat-eight engine A flat-eight engine, also called a horizontally-opposed eight, is an eight-cylinder piston engine with two banks of four inline cylinders, one on each side of a central crankshaft, 180° apart.
In a flat-eight engine, the connecting rods for corres ...
s have been used in several racing cars, mostly by Porsche in the 1960s.
*
Flat-ten engine A flat-ten engine, also known as a horizontally opposed-ten, is a ten-cylinder piston engine with five cylinders on each side of a central crankshaft.
There are no known flat-ten engines which reached production.
In the early 1960s, Chevrolet bui ...
s are not known to have reached production. A prototype road car engine was built by
Chevrolet
Chevrolet ( ), colloquially referred to as Chevy and formally the Chevrolet Motor Division of General Motors Company, is an American automobile division of the American manufacturer General Motors (GM). Louis Chevrolet (1878–1941) and ous ...
in the 1960s.
*
Flat-twelve engine
A flat-twelve engine, also known as a horizontally opposed-twelve, is a twelve-cylinder piston engine with six cylinders on each side of a central crankshaft.
Flat-twelve engines are less common than V12 engines, but they have been used in vario ...
s have been used in various racing cars, notably the
Porsche 917K
The Porsche 917 is a sports prototype race car developed by German manufacturer Porsche to exploit the regulations regarding the construction of 5-litre sports cars. Powered by a Type 912 flat-12 engine which was progressively enlarged from ...
, during the 1960s and 1970s, and in
Ferrari
Ferrari S.p.A. (; ) is an Italian luxury sports car manufacturer based in Maranello, Italy. Founded by Enzo Ferrari (1898–1988) in 1939 from the Alfa Romeo racing division as ''Auto Avio Costruzioni'', the company built its first car in ...
road cars from 1973-1996.
*
Flat-sixteen engine
A flat-sixteen engine, also known as a horizontally opposed-sixteen, is a sixteen-cylinder piston engine with eight cylinders on each side of a central crankshaft.
Flat-sixteen engines are less common than V16 engines, with only a couple of pr ...
s are not known to have reached production. Prototype racing car engines were built by
Coventry
Coventry ( or ) is a City status in the United Kingdom, city in the West Midlands (county), West Midlands, England. It is on the River Sherbourne. Coventry has been a large settlement for centuries, although it was not founded and given its ...
and Porsche in the 1960s and 1970s.
Boxer configuration
![R68-opposed-cylinders](https://upload.wikimedia.org/wikipedia/commons/6/63/R68-opposed-cylinders.jpg)
Most flat engines use a "boxer" configuration, where each pair of opposing pistons move inwards and outwards at the same time, somewhat like boxing competitors punching their gloves together before a fight.
Boxer engines have low vibrations, since they are the only common configuration that have no unbalanced forces regardless of the number of cylinders. Boxer engines therefore do not require a
balance shaft[ or counterweights on the crankshaft to balance the weight of the reciprocating parts. However, a rocking couple is present, since each cylinder is slightly offset from its opposing pair, due to the distance between the ]crankpin
A crankpin or crank pin, also known as a rod bearing journal, is a mechanical device in an engine which connects the crankshaft to the connecting rod for each cylinder. It has a cylindrical surface, to allow the crankpin to rotate relative to the ...
s along the crankshaft.[
]
180-degree V engine
An alternative configuration for flat engines is as a 180-degree V engine
A V engine, sometimes called a Vee engine, is a common configuration for internal combustion engines. It consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common crankshaft. These cylinder ...
, which has been used on most twelve-cylinder flat engines. In this configuration, each pair of pistons shares a crankpin
A crankpin or crank pin, also known as a rod bearing journal, is a mechanical device in an engine which connects the crankshaft to the connecting rod for each cylinder. It has a cylindrical surface, to allow the crankpin to rotate relative to the ...
, rather than the boxer configuration where each piston has its own crankpin.
Aviation use
In 1902, the Pearse monoplane (which would later become one of the first aircraft to achieve flight) was powered by a flat-twin engine. Amongst the first commercially produced aircraft to use a flat engine is the 1909 Santos-Dumont Demoiselle
The Santos-Dumont ''Demoiselle'' was a series of aircraft built in France by world aviation pioneer Alberto Santos-Dumont. They were light-weight monoplanes with a wire-braced wing mounted above an open-framework fuselage built from bamboo. The ...
range of airplanes, which was powered by boxer-twin engines.
Several boxer-four engines have been produced specifically for light aircraft. Several manufacturers produced boxer-six aircraft engines during the 1930s and 1940s.
During World War II, boxer-twin engines called the "Riedel starter" were used as a starter motor/mechanical APU
APU or Apu may refer to:
Film and television
* ''The Apu Trilogy'', a series of three Bengali films, directed by Satyajit Ray, with the fictional character Apu Roy, comprising:
** ''Pather Panchali'' (''Song of the Little Road'') (1955), the first ...
for the early German jet engines such as the Junkers Jumo 004 and BMW 003
The BMW 003 (full RLM designation 109-003) is an early axial turbojet engine produced by BMW AG in Germany during World War II. The 003 and the Junkers Jumo 004 were the only German turbojet engines to reach production during World War II.
W ...
. Designed by Norbert Riedel
Norbert Riedel (* 1 April 1912 in Jägerndorf, Sudetenland, then Austria-Hungary; † 24 February 1963 in Zürs am Arlberg, Austria) was an engineer and entrepreneur.
Life
Riedel studied mechanical engineering and worked in the 1930s, first with ...
, these engines have a very oversquare stroke ratio of 2:1 so that they could fit within the intake diverter, directly forward of the turbine compressor.
Motorcycle use
Flat engines offer several advantages for motorcycles including a low center of mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
, low vibration, suitability for shaft drive, and even cooling of the cylinders (for air-cooled engines). The most common design of flat engines for motorcycles is the boxer-twin, beginning with the 1905 Fée manufactured by the Light Motors Company flat-twin, which was the first production motorcycle to use a flat engine. BMW Motorrad
BMW Motorrad is the motorcycle brand of BMW, part of its Corporate and Brand Development division. It has produced motorcycles since 1923, and achieved record sales for the fifth year in succession in 2015. With a total of 136,963 vehicles sold i ...
have a long history of boxer-twin motorcycles, beginning in 1923 with the BMW R32
The BMW R32 was the first motorcycle produced by BMW under the BMW name. An aircraft engine manufacturer during World War I, BMW was forced to diversify after the Treaty of Versailles banned the German air force and German aircraft manufacture. ...
Several motorcycles have been produced with flat-four engines, such as the 1938-1939 Zündapp K800 and the 1974-1987 Honda Gold Wing
The Honda Gold Wing is a series of touring motorcycles manufactured by Honda. Gold Wings feature shaft drive and a flat engine. Mooted by press in September 1974 as "The world's biggest motor cycle manufacturer's first attack on the over-750cc ...
. In 1987, the Honda Gold Wing engine was upsized to a flat-six design.
Automotive use
When used in cars, advantages of flat engines are a low center of mass
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
(which improves the handling of the car), short length, low vibration and suitability for air cooling (due to the well exposed, large surface area, cylinder heads and short length). However the larger width of flat engines (compared with the more common inline and V layouts) is a drawback, particularly when the engine is located between the steered wheels.
Flat engines were used by various automobile manufacturers— mostly with a boxer-four design— up until the late 1990s. Since then, only Porsche and Subaru have remained as significant manufacturers of flat engines.
Drivetrain layout
Due to the short length of flat engines, locating a flat engine outside of the car's wheelbase
In both road and rail vehicles, the wheelbase is the horizontal distance between the centers of the front and rear wheels. For road vehicles with more than two axles (e.g. some trucks), the wheelbase is the distance between the steering (front ...
results in minimal overhang. Therefore, many cars with flat engines have used a rear-engine, rear-wheel-drive layout
In automotive design, an RR, or rear-engine, rear-wheel-drive layout places both the engine and drive wheels at the rear of the vehicle. In contrast to the RMR layout, the center of mass of the engine is between the rear axle and the rear bumpe ...
. Examples include the flat-twin BMW 600
The BMW 600 is a four-seater microcar produced by the German automaker BMW from mid-1957 until November 1959. Partially based on the BMW Isetta two-seater, it was BMW's first postwar four-seater economy car. It was not a sales success, but it b ...
(1957-1959) and BMW 700
The BMW 700 is a small rear-engined car which was produced by BMW in various models from August 1959 to November 1965. It was the first BMW automobile with a monocoque structure. The 700 was a sales success at a time when BMW was close to fina ...
(1959-1965); the flat-four Tatra 97
The Tatra 97 (T97) is a Czechoslovak mid-size car built by Tatra in Kopřivnice, Moravia from 1936 to 1939.
History
The Tatra 97 was designed to complement two full-size cars in the Tatra range: the Tatra 77 launched in 1934 and the Tatra ...
(1936-1939), Volkswagen Beetle
The Volkswagen Beetle—officially the Volkswagen Type 1, informally in German (meaning "beetle"), in parts of the English-speaking world the Bug, and known by many other nicknames in other languages—is a two-door, rear-engine economy car, ...
(1938-2003) and Porsche 356
The Porsche 356 is a sports car that was first produced by Austrian company Porsche Salzburg, Porsche Konstruktionen GesmbH (1948–1949), and then by German company Porsche, Dr. Ing. h. c. F. Porsche GmbH (1950–1965). It was Porsche's first ...
(1948-1965); and the flat-six Chevrolet Corvair
The Chevrolet Corvair is a compact car manufactured by Chevrolet for model years 1960–1969 in two generations. A response to the Volkswagen Beetle, it remains the only American-designed, mass-produced passenger car with a rear-mounted, air- ...
(1959-1969), Porsche 911
The Porsche 911 (pronounced ''Nine Eleven'' or in german: Neunelfer) is a two-door 2+2 high performance rear-engined sports car introduced in September 1964 by Porsche AG of Stuttgart, Germany. It has a rear-mounted flat-six engine and origin ...
(1963-present), and Tucker 48
The Tucker 48, commonly referred to as the Tucker Torpedo, was an automobile conceived by Preston Tucker while in Ypsilanti, Michigan and briefly produced in Chicago, Illinois in 1948. Only 51 cars were made including their prototype before the c ...
(1947-1948).
The opposite layout, front-engine front-wheel drive, was also common for cars with flat engines. Examples include the Citroën 2CV
The Citroën 2CV (french: link=no, deux chevaux(-vapeur), , lit. "two steam horse(power)s", meaning "two ''taxable'' horsepower") is an air-cooled front-engine, front-wheel-drive, economy family car, introduced at the 1948 Paris Mondial d ...
(1948-1990), Panhard Dyna X
The Panhard Dyna X was a lightweight berline designed by the engineer Jean Albert Grégoire and first exhibited as the AFG ''(Aluminium Français Grégoire)'' Dyna at the Paris Motor Show in 1946.
Conception and development
Mindful of the preca ...
(1948-1954), Lancia Flavia
The Lancia Flavia (Tipo 815/819/820) is an executive car produced by Lancia in Italy from 1961 to 1971. Production continued as the Lancia 2000 from 1971 to 1975.
The Flavia was launched with a 1,500 cc engine at the 1960 Turin Motor Sho ...
(1961-1970), Citroën GS
The GS is a front-engine, front-drive, four or five door, five passenger family car manufactured and marketed by Citroën in two series: for model years 1970-1979 in fastback saloon and estate bodystyles and subsequently as the GSA for model yea ...
(1970-1986), Alfa Romeo Alfasud
The Alfa Romeo Alfasud (Type 901, 902 and 904) is a small family car manufactured and marketed from 1971 to 1989 by Alfa Romeo as a front-engine, four-door, five-passenger entry-level model over a single generation — with facelifts in 1977 a ...
(1971-1989) and Subaru Leone
The Subaru Leone is a compact car produced by the Japanese car manufacturer Subaru from 1971 to 1994. The word ''leone'' is Italian for lion.
It was released as a replacement for the Subaru 1000 and was the predecessor of the Subaru Impreza. Al ...
(1971-1994).
Subaru have been producing cars with a front-engine, four-wheel-drive layout
In automotive design, an F4, or front-engine, four-wheel drive (4WD) layout places the internal combustion engine at the front of the vehicle and drives all four roadwheels. This layout is typically chosen for better control on many surfaces, ...
powered by flat engines (mostly boxer-four engines) since 1971. Examples include the Subaru Leone
The Subaru Leone is a compact car produced by the Japanese car manufacturer Subaru from 1971 to 1994. The word ''leone'' is Italian for lion.
It was released as a replacement for the Subaru 1000 and was the predecessor of the Subaru Impreza. Al ...
(1971-1994), Subaru Legacy
The is a mid-size car built by Japanese automobile manufacturer Subaru since 1989. The maker's flagship car, it is unique in its class for offering all-wheel drive as a standard feature, and Subaru's traditional boxer engine. The Legacy was sol ...
(1989-present) and Subaru Impreza
The is a compact car that has been manufactured by the Japanese automaker Subaru since 1992. It was introduced as a replacement for the Leone, with the predecessor's EA series engines replaced by the new EJ series. It is now in its sixth gen ...
(1992–present). The front half-shafts come out of a front differential that is part of the gearbox. A rear driveshaft connects the gearbox to the rear half-shafts.
The traditional front-engine, rear-wheel-drive layout is relatively uncommon for cars with flat engines, however some examples include the Toyota 86 / Subaru BRZ (2012–present), Jowett Javelin (1947-1953), Glas Isar
The Glas Isar is a small two door four seater car produced by Hans Glas GmbH at their Dingolfing plant. The car was first presented as the Goggomobil T600 in September 1957 at the Frankfurt Motor Show, with volume production starting in August ...
(1958-1965) and the Tatra 11
The Tatra T11 is an automobile that was produced from 1923 through 1927. It was the first Tatra model to use the unique combination of major components that are still in use on the trucks produced by Tatra to this day.
Origins
Hans Ledwinka crea ...
(1923-1927).
History
The first flat engine was produced in 1897 by German engineer Karl Benz
Carl Friedrich Benz (; 25 November 1844 – 4 April 1929), sometimes also Karl Friedrich Benz, was a German engine designer and automotive engineer. His Benz Patent Motorcar from 1885 is considered the first practical modern automobile and fir ...
. Called the ''kontra'' engine, it was a boxer-twin design. Early uses of flat engines in cars include the 1900 Lanchester 8 hp Phaeton
The Lanchester 8 hp Phaeton is a brass era automobile designed by Frederick W. Lanchester, developed and built by the Lanchester Motor Company
The Lanchester Motor Company Limited was a car manufacturer located until early 1931 at Armourer M ...
boxer-twin, the 1901 Wilson-Pilcher
Wilson-Pilcher was an English car company founded in 1901 and acquired by Sir WG Taken Armstrong Whitworth & Co., Limited in 1904.
History
The company ''Wilson-Pilcher'' was founded in 1901 by Walter Gordon Wilson in London to produce autom ...
boxer-four, the 1904 Wilson-Pilcher ''18/24 HP'' boxer-six and the 1903 Ford Model A, the 1904 Ford Model C
The Ford Model C is an automobile that was produced by Ford Motor Company. Introduced in 1904, it was a revision of the Model A with a more modern appearance. It had a slightly more powerful engine and a longer wheelbase. Built at the Ford Pique ...
and the 1905 Ford Model F
The Ford Model F is an automobile produced by Ford. It was a development of the Model A and Model C, but was larger, more modern, and more luxurious. Production started in 1905 and ended in 1906 after about 1,000 were made. It was built at the ...
.
In 1938, the Volkswagen Beetle
The Volkswagen Beetle—officially the Volkswagen Type 1, informally in German (meaning "beetle"), in parts of the English-speaking world the Bug, and known by many other nicknames in other languages—is a two-door, rear-engine economy car, ...
(then called the "KdF-Wagen") was released with a rear-mounted flat-four engine. This Volkswagen air-cooled engine
The Volkswagen air-cooled engine is an air-cooled, gasoline-fuelled, boxer engine with four horizontally opposed cast-iron cylinders, cast aluminum alloy cylinder heads and pistons, magnesium-alloy crankcase, and forged steel crankshaft and ...
was produced for many years and also used in the Volkswagen Type 2
The Volkswagen Type 2, known officially (depending on body type) as the Transporter, Kombi or Microbus, or, informally, as the Bus (US), Camper (UK) or Bulli (Germany), is a forward control light commercial vehicle introduced in 1950 by the Ge ...
(Transporter, Kombi or Microbus), the Volkswagen Karmann Ghia
The Volkswagen Karmann Ghia is a sports car marketed in 2+2 coupe (1955–1974) and 2+2 convertible (1957–1974) body styles by Volkswagen. Internally designated the Type 14, the Karmann Ghia combined the chassis and mechanicals of the Type 1 (B ...
sports car and the Volkswagen Type 3
The Volkswagen Type 3 is a compact car manufactured and marketed by Volkswagen from 1961-1973. Introduced at the 1961 Frankfurt Motor Show, ''Internationale Automobil-Ausstellung (IAA)'', the Type 3 was marketed as the Volkswagen 1500 and later ...
compact car. A water-cooled version, known as the Wasserboxer
The Volkswagen wasserboxer is a four cylinder horizontally opposed pushrod overhead-valve (OHV) petrol engine developed by Volkswagen. The engine is water-cooled, and takes its name from the german: "wasserboxer" ("Water-boxer"); with "boxer" b ...
, was introduced in 1982 and eventually replaced the air-cooled versions.
The majority of sports cars throughout Porsche's history are powered by flat engines, beginning with its first car; the 1948-1965 Porsche 356
The Porsche 356 is a sports car that was first produced by Austrian company Porsche Salzburg, Porsche Konstruktionen GesmbH (1948–1949), and then by German company Porsche, Dr. Ing. h. c. F. Porsche GmbH (1950–1965). It was Porsche's first ...
used an air-cooled boxer-four engine. Also using boxer-four engines were the 1969-1976 Porsche 914
The Porsche 914 or VW-Porsche 914 is a mid-engined sports car designed, manufactured and marketed collaboratively by Volkswagen and Porsche from 1969 until 1976. It was only available as a targa-topped two-seat roadster powered by either a ...
, the 1965-1969 Porsche 912
The Porsche 912 is a sports car produced by Porsche AG of Stuttgart, Germany, for the 1965 through 1969 model years. An entry-level variant of the 911, it was also offered in compact 2+2 Coupé and Targa body styles. The nimble-handling 912 was a ...
and the 2016-present Porsche Boxster/Cayman (982). The Porsche 911
The Porsche 911 (pronounced ''Nine Eleven'' or in german: Neunelfer) is a two-door 2+2 high performance rear-engined sports car introduced in September 1964 by Porsche AG of Stuttgart, Germany. It has a rear-mounted flat-six engine and origin ...
has exclusively used boxer-six engines from its introduction in 1964 until the present. In 1997, the Porsche 911 switched from being air-cooled to water-cooled.
Porsche flat-eight engines were used in various racing cars throughout the 1960s, such as the 1962 Porsche 804
The Porsche 804 is a single-seat, open-wheeled racing car produced by Porsche to compete in Formula One (F1). It raced for a single season in 1962 in the 1½ litre formula.
Background
In 1957 the Fédération Internationale de l'Automobile ...
Formula One car and the 1968-1971 Porsche 908
The Porsche 908 was a racing car from Porsche, introduced in 1968 to continue the Porsche 906- Porsche 910- Porsche 907 series of models designed by Helmuth Bott (chassis) and Hans Mezger (engine) under the leadership of racing chief Ferdinand P ...
sports car. A flat-twelve engine was also produced by Porsche for the 1969-1973 Porsche 917 sports car.
Chevrolet
Chevrolet ( ), colloquially referred to as Chevy and formally the Chevrolet Motor Division of General Motors Company, is an American automobile division of the American manufacturer General Motors (GM). Louis Chevrolet (1878–1941) and ous ...
used a horizontally opposed air-cooled 6 cylinder engine in its Corvair line during its entire production run from 1960-1969 in various applications and power ratings, including one of the first uses of a turbocharger in a mass-produced automobile.
The Subaru EA engine
The Subaru EA engine is a series of automobile internal combustion engines manufactured by Subaru, a division of Fuji Heavy Industries. All EA series engines are of a flat-4 design, and have always been water cooled.
Design and history
Prior ...
was introduced in 1966 and began Subaru's line of boxer-four engines that remain in production to this day. Most of Subaru's models are powered by a boxer-four engine in either naturally aspirated or turbocharged form. A print ad for the 1973 Subaru GL coupe referred to the engine as "quadrozontal". The company also produced boxer-six engines from 1988–1996 and 2001–2019. In 2008, the Subaru EE engine became the world's first passenger car diesel boxer engine. This engine is a turbocharged boxer-four with common rail fuel injection.
Ferrari used flat-twelve engines for various Formula One cars in the 1970s. A road car flat-twelve engine (using a 180-degree V12 configuration) was used for the 1973-1984 Ferrari Berlinetta Boxer
The Ferrari Berlinetta Boxer (BB) is series of sports cars produced by Ferrari in Italy between 1973 and 1984. The BB was designed by Leonardo Fioravanti at Pininfarina. The first BB model, the 365 GT4 BB, replaced the front engined Daytona and ...
, 1984-1996 Ferrari Testarossa
The Ferrari Testarossa (Type F110) is a 12-cylinder mid-engine sports car manufactured by Ferrari, which went into production in 1984 as the successor to the Ferrari Berlinetta Boxer. The Pininfarina-designed car was originally produced from ...
and their derivatives.
Toyota uses the designation ''Toyota 4U-GSE'' for the boxer-four engine in the Toyota-badged versions of the Toyota 86 / Subaru BRZ twins, although the engine is actually designed and built by Subaru as the Subaru FA20 engine.
See also
* H engine
An H engine is a piston engine comprising two separate flat engines (complete with separate crankshafts), most often geared to a common output shaft. The name "H engine" is due to the engine blocks resembling a letter "H" when viewed from the fr ...
* V engine
A V engine, sometimes called a Vee engine, is a common configuration for internal combustion engines. It consists of two cylinder banks—usually with the same number of cylinders in each bank—connected to a common crankshaft. These cylinder ...
* W engine
A W engine is a type of piston engine where three or four cylinder banks use the same crankshaft, resembling the letter W when viewed from the front.
W engines with three banks of cylinders are also called "broad arrow" engines, due to their shap ...
* X engine
An X engine is a piston engine with four banks of cylinders around a common crankshaft, such that the cylinders form an "X" shape when viewed from front-on.
The advantage of an X engine is that it is shorter than a V engine of the same number o ...
* Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ...
* History of the internal combustion engine
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 i ...
References
{{Authority control
Flat
Flat or flats may refer to:
Architecture
* Flat (housing), an apartment in the United Kingdom, Ireland, Australia and other Commonwealth countries
Arts and entertainment
* Flat (music), a symbol () which denotes a lower pitch
* Flat (soldier), ...