Governments and private organizations have developed car classification schemes that are used for various purposes including regulation and categorization, among others. This article details used classification schemes in use worldwide; this following table summarises common classifications for cars. Microcars and their Japanese equivalent— kei cars— are the smallest category of automobile. Microcars straddle the boundary between car and motorbike, are covered by separate regulations to normal cars, resulting in relaxed requirements for registration and licensing. Engine size is 700 cc or less, microcars have three or four wheels. Microcars are most popular in Europe, where they originated following World War II; the predecessors to micro cars are Cycle cars. Kei cars have been used in Japan since 1949. Examples of microcars and kei cars: Honda Life Isetta Tata Nano The smallest category of vehicles that are registered as normal cars is called A-segment in Europe, or "city car" in Europe and the United States.
The United States Environmental Protection Agency defines this category as "minicompact", however this term is not used. The equivalents of A-segment cars have been produced since the early 1920s, however the category increased in popularity in the late 1950s when the original Fiat 500 and BMC Mini were released. Examples of A-segment / city cars / minicompact cars: Fiat 500 Hyundai i10 Toyota Aygo The next larger category small cars is called B-segment Europe, supermini in the United Kingdom and subcompact in the United States; the size of a subcompact car is defined by the United States Environmental Protection Agency, as having a combined interior and cargo volume of between 85–99 cubic feet. Since the EPA's smaller minicompact category is not as used by the general public, A-segment cars are sometimes called subcompacts in the United States. In Europe and Great Britain, the B-segment and supermini categories do not any formal definitions based on size. Early supermini cars in Great Britain include Vauxhall Chevette.
In the United States, the first locally-built subcompact cars were the 1970 AMC Gremlin, Chevrolet Vega, Ford Pinto. Examples of B-segment / supermini / subcompact cars: Chevrolet Sonic Hyundai Accent Volkswagen Polo The largest category of small cars is called C-segment or small family car in Europe, compact car in the United States; the size of a compact car is defined by the United States Environmental Protection Agency, as having a combined interior and cargo volume of 100–109 cu ft. Examples of C-segment / compact / small family cars: Peugeot 308 Toyota Auris Renault Megane In Europe, the third largest category for passenger cars is called D-segment or large family car. In the United States, the equivalent term is intermediate cars; the U. S. Environmental Protection Agency defines a mid-size car as having a combined passenger and cargo volume of 110–119 cu ft. Examples of D-segment / large family / mid-size cars: Chevrolet Malibu Ford Mondeo Kia Optima In Europe, the second largest category for passenger cars is E-segment / executive car, which are luxury cars.
In other countries, the equivalent terms are full-size car or large car, which are used for affordable large cars that aren't considered luxury cars. Examples of non-luxury full-size cars: Chevrolet Impala Ford Falcon Toyota Avalon Minivan is an American car classification for vehicles which are designed to transport passengers in the rear seating row, have reconfigurable seats in two or three rows; the equivalent terms in British English are people carrier and people mover. Minivans have a'one-box' or'two-box' body configuration, a high roof, a flat floor, a sliding door for rear passengers and high H-point seating. Mini MPV is the smallest size of MPVs and the vehicles are built on the platforms of B-segment hatchback models. Examples of Mini MPVs: Fiat 500L Honda Fit Ford B-Max Compact MPV is the middle size of MPVs; the Compact MPV size class sits between large MPV size classes. Compact MPVs remain predominantly a European phenomenon, although they are built and sold in many Latin American and Asian markets.
Examples of Compact MPVs: Renault Scenic Volkswagen Touran Ford C-Max The largest size of minivans is referred to as'Large MPV' and became popular following the introduction of the 1984 Renault Espace and Dodge Caravan. Since the 1990s, the smaller Compact MPV and Mini MPV sizes of minivans have become popular. If the term'minivan' is used without specifying a size, it refers to a Large MPV. Examples of Large MPVs: Dodge Grand Caravan Ford S-Max Toyota Sienna The premium compact class is the smallest category of luxury cars, it became popular in the mid-2000s, when European manufacturers— such as Audi, BMW and Mercedes-Benz— introduced new entry level models that were smaller and cheaper than their compact executive models. Examples of premium compact cars: Audi A3 Buick Verano Lexus CT200h A compact executive car is a premium car larger than a premium compact and smaller than an executive car. Compact executive cars are equivalent size to mid-size cars and are part of the D-segment in the European car classification.
In North American terms, close equivalents are "luxury compact" and "entry-level luxury car", although the latter is used for the smaller premium compact cars. Examples of compact executive cars: Audi A4 BMW 3 Series Buick Regal An executive car is a premium car larger than a compact executive and smaller than an full-size luxury car. Executive cars are classified as E-segment cars in the European car classification. In the United States and several other coun
Full-size car— known as large car is a vehicle size class which originated in the United States and is used for cars larger than mid-size cars. It is the largest size class for cars; the equivalent European categories are E-segment and executive car. After World War II, the majority of full-size cars have used the sedan and station wagon body styles, however in recent years most full-size cars have been sedans; the highest-selling full-size car nameplate is the Chevrolet Impala, sold as a full-size car from 1958 to 1986 and from 1994 to 1996. The United States Environmental Protection Agency Fuel Economy Regulations for 1977 and Later Model Year includes definitions for classes of automobiles. Based on the combined passenger and cargo volume, large cars are defined as having an interior volume index of more than 120 cu ft for sedan models, or 160 cu ft for station wagons. From the introduction of the Ford Flathead V8 in the 1930s until the 1980s, most North American full-size cars were powered by V8 engines.
However, V6 engines and straight-six engines have been available on American full-size cars, have become common since the downsizing of full-sized cars in the 1980s. The lineage of mass-produced full-size American cars begins with the 1908 Ford Model T. In 1923, General Motors introduced the Chevrolet Superior, becoming the first vehicle to adopt a common chassis for several brands. In comparison to the cars of the 21st century, these vehicles are small in width. From the 1920s to the 1950s, most manufacturers produced model lines in a single size, growing in size with each model redesign. While length and wheelbase varied between model lines, width was a constant dimension, as the American federal government required the addition of clearance lights on a width past 80 inches. In 1960, following the introduction of compact cars, the "full-size car" designation came into wider use. In the 1960s, the term was applied to the traditional car lines of lower-price brands, including Chevrolet and Plymouth.
As a relative term, full-size cars were marketed by the same brands offering compact cars, with entry-level cars for buyers seeking the roominess of a luxury car at a lower cost. Into the 1970s, the same vehicles could transport up to six occupants comfortably, at the expense of high fuel consumption; the sales of full-size vehicles in the United States declined after the early 1970s fuel crisis. By that time, full-size cars had grown to wheelbases of 121–127 inches and overall lengths of around 225 in. In response to the 1978 implementation of CAFE, American manufacturers implemented downsizing to improve fuel economy, with full-size vehicles as the first model lines to see major change. While General Motors and Ford would reduce the exterior footprint of their full-size lines to that of their intermediates, AMC withdrew its Ambassador and Matador full-size lines. To save production costs, Chrysler repackaged its intermediates as full-size vehicles, exiting the segment in 1981. During the 1980s, to further comply with more stringent CAFE standards, manufacturers further reduced the exterior footprint of several model lines out of the full-size segment into the mid-size class.
For 1982, Chrysler exited the full-size segment with the mid-size Dodge Diplomat and Plymouth Gran Fury serving as its largest sedan lines. Following the 1985 model year, General Motors replaced most of its full-size model lines with front-wheel drive mid-size sedans. Developed to replace the Ford LTD Crown Victoria, the 1986 Ford Taurus was produced alongside it as the Ford mid-size model line. After abandoning the full-size segment for compact cars and minivans, Chrysler gained reentry into the full-size segment in 1988 with the Eagle Premier. Developed by AMC before its acquisition by Chrysler, the Premier was a version of the front-wheel drive Renault 25 adapted for North America. From the 1980s to the 1990s, the market share of full-size cars began to decline. From 1960 to 1994, the market share of full-size cars declined from 65 percent to 8.3 percent. From 1990 to 1992, both GM and Ford redesigned its full-size car lines for the first time since the late 1970s. For 1992, Chrysler developed its first front-wheel drive full-size car line, replacing the Eagle Premier/Dodge Monaco with the Chrysler LH cars.
The same year, the Buick Roadmaster was introduced, becoming the first rear-wheel drive GM model line adopted outside of Chevrolet and Cadillac since 1985. In 1995, the Toyota Avalon was introduced, becoming the first Japanese non-luxury full-size car with six seats to be sold in the North America; the 1989 Lexus LS400 luxury sedan was the first Japanese full-size car sold in North America. Following the 1996 model year, GM ended production of rear-wheel drive sedans, with full-size vehicles becoming exclusive to Cadillac. From 1997 to 2016, the longest vehicle produced by an American manufacturer was a Lincoln. By 2000, with the sole exception of the Ford Crown Victoria, Mercury Grand Marquis, Lincoln Town Car, full-size cars had abandoned rear-wheel drive and body-on-frame construction. Instead of model lineage, the EPA "large car" definition of over 120 interior cubic feet came into wide use
An engine or motor is a machine designed to convert one form of energy into mechanical energy. Heat engines, like the internal combustion engine, burn a fuel to create heat, used to do work. Electric motors convert electrical energy into mechanical motion, pneumatic motors use compressed air, clockwork motors in wind-up toys use elastic energy. In biological systems, molecular motors, like myosins in muscles, use chemical energy to create forces and motion; the word engine derives from Old French engin, from the Latin ingenium–the root of the word ingenious. Pre-industrial weapons of war, such as catapults and battering rams, were called siege engines, knowledge of how to construct them was treated as a military secret; the word gin, as in cotton gin, is short for engine. Most mechanical devices invented during the industrial revolution were described as engines—the steam engine being a notable example. However, the original steam engines, such as those by Thomas Savery, were not mechanical engines but pumps.
In this manner, a fire engine in its original form was a water pump, with the engine being transported to the fire by horses. In modern usage, the term engine describes devices, like steam engines and internal combustion engines, that burn or otherwise consume fuel to perform mechanical work by exerting a torque or linear force. Devices converting heat energy into motion are referred to as engines. Examples of engines which exert a torque include the familiar automobile gasoline and diesel engines, as well as turboshafts. Examples of engines which produce thrust include rockets; when the internal combustion engine was invented, the term motor was used to distinguish it from the steam engine—which was in wide use at the time, powering locomotives and other vehicles such as steam rollers. The term motor derives from the Latin verb moto which means to maintain motion, thus a motor is a device. Motor and engine are interchangeable in standard English. In some engineering jargons, the two words have different meanings, in which engine is a device that burns or otherwise consumes fuel, changing its chemical composition, a motor is a device driven by electricity, air, or hydraulic pressure, which does not change the chemical composition of its energy source.
However, rocketry uses the term rocket motor though they consume fuel. A heat engine may serve as a prime mover—a component that transforms the flow or changes in pressure of a fluid into mechanical energy. An automobile powered by an internal combustion engine may make use of various motors and pumps, but all such devices derive their power from the engine. Another way of looking at it is that a motor receives power from an external source, converts it into mechanical energy, while an engine creates power from pressure. Simple machines, such as the club and oar, are prehistoric. More complex engines using human power, animal power, water power, wind power and steam power date back to antiquity. Human power was focused by the use of simple engines, such as the capstan, windlass or treadmill, with ropes and block and tackle arrangements; these were used in cranes and aboard ships in Ancient Greece, as well as in mines, water pumps and siege engines in Ancient Rome. The writers of those times, including Vitruvius and Pliny the Elder, treat these engines as commonplace, so their invention may be more ancient.
By the 1st century AD, cattle and horses were used in mills, driving machines similar to those powered by humans in earlier times. According to Strabo, a water powered mill was built in Kaberia of the kingdom of Mithridates during the 1st century BC. Use of water wheels in mills spread throughout the Roman Empire over the next few centuries; some were quite complex, with aqueducts and sluices to maintain and channel the water, along with systems of gears, or toothed-wheels made of wood and metal to regulate the speed of rotation. More sophisticated small devices, such as the Antikythera Mechanism used complex trains of gears and dials to act as calendars or predict astronomical events. In a poem by Ausonius in the 4th century AD, he mentions a stone-cutting saw powered by water. Hero of Alexandria is credited with many such wind and steam powered machines in the 1st century AD, including the Aeolipile and the vending machine these machines were associated with worship, such as animated altars and automated temple doors.
Medieval Muslim engineers employed gears in mills and water-raising machines, used dams as a source of water power to provide additional power to watermills and water-raising machines. In the medieval Islamic world, such advances made it possible to mechanize many industrial tasks carried out by manual labour. In 1206, al-Jazari employed a crank-conrod system for two of his water-raising machines. A rudimentary steam turbine device was described by Taqi al-Din in 1551 and by Giovanni Branca in 1629. In the 13th century, the solid rocket motor was invented in China. Driven by gunpowder, this simplest form of internal combustion engine was unable to deliver sustained power, but was useful for propelling weaponry at high speeds towards enemies in battle and for fireworks. After invention, this innovation spread throughout Europe; the Watt steam engine was the first type of steam engine to make use of steam at a pressure just above atmospheric to drive the piston he
A transmission is a machine in a power transmission system, which provides controlled application of the power. The term transmission refers to the gearbox that uses gears and gear trains to provide speed and torque conversions from a rotating power source to another device. In British English, the term transmission refers to the whole drivetrain, including clutch, prop shaft and final drive shafts. In American English, the term refers more to the gearbox alone, detailed usage differs; the most common use is in motor vehicles, where the transmission adapts the output of the internal combustion engine to the drive wheels. Such engines need to operate at a high rotational speed, inappropriate for starting and slower travel; the transmission reduces the higher engine speed to the slower wheel speed, increasing torque in the process. Transmissions are used on pedal bicycles, fixed machines, where different rotational speeds and torques are adapted. A transmission has multiple gear ratios with the ability to switch between them as speed varies.
This switching may be done automatically. Directional control may be provided. Single-ratio transmissions exist, which change the speed and torque of motor output. In motor vehicles, the transmission is connected to the engine crankshaft via a flywheel or clutch or fluid coupling because internal combustion engines cannot run below a particular speed; the output of the transmission is transmitted via the driveshaft to one or more differentials, which drives the wheels. While a differential may provide gear reduction, its primary purpose is to permit the wheels at either end of an axle to rotate at different speeds as it changes the direction of rotation. Conventional gear/belt transmissions are not the only mechanism for speed/torque adaptation. Alternative mechanisms include power transformation. Hybrid configurations exist. Automatic transmissions use a valve body to shift gears using fluid pressures in response to speed and throttle input. Early transmissions included the right-angle drives and other gearing in windmills, horse-powered devices, steam engines, in support of pumping and hoisting.
Most modern gearboxes are used to increase torque while reducing the speed of a prime mover output shaft. This means that the output shaft of a gearbox rotates at a slower rate than the input shaft, this reduction in speed produces a mechanical advantage, increasing torque. A gearbox can be set up to do the opposite and provide an increase in shaft speed with a reduction of torque; some of the simplest gearboxes change the physical rotational direction of power transmission. Many typical automobile transmissions include the ability to select one of several gear ratios. In this case, most of the gear ratios are used to slow down the output speed of the engine and increase torque. However, the highest gears may be "overdrive" types. Gearboxes have found use in a wide variety of different—often stationary—applications, such as wind turbines. Transmissions are used in agricultural, construction and automotive equipment. In addition to ordinary transmission equipped with gears, such equipment makes extensive use of the hydrostatic drive and electrical adjustable-speed drives.
The simplest transmissions called gearboxes to reflect their simplicity, provide gear reduction, sometimes in conjunction with a right-angle change in direction of the shaft. These are used on PTO-powered agricultural equipment, since the axial PTO shaft is at odds with the usual need for the driven shaft, either vertical, or horizontally extending from one side of the implement to another. More complex equipment, such as silage choppers and snowblowers, have drives with outputs in more than one direction; the gearbox in a wind turbine converts the slow, high-torque rotation of the turbine into much faster rotation of the electrical generator. These are more complicated than the PTO gearboxes in farm equipment, they weigh several tons and contain three stages to achieve an overall gear ratio from 40:1 to over 100:1, depending on the size of the turbine. The first stage of the gearbox is a planetary gear, for compactness, to distribute the enormous torque of the turbine over more teeth of the low-speed shaft.
Durability of these gearboxes has been a serious problem for a long time. Regardless of where they are used, these simple transmissions all share an important feature: the gear ratio cannot be changed during use, it is fixed at the time. For transmission types that overcome this issue, see Continuously variable transmission known as CVT. Many applications require the availability of multiple gear ratios; this is to ease the starting and stopping of a mechanical system, though another important need is that of maintaining good fuel efficiency. The need for a transmission in an automobile is a consequence of the characteristics of the internal combustion engine. Eng
A suicide door is the slang term for an automobile door hinged at its rear rather than the front. Such doors were used on horse-drawn carriages, but are found on modern vehicles because they are perceived as being unsafe. Popularized in the custom car trade, the term is avoided by major automobile manufacturers in favor of alternatives such as "coach doors", "FlexDoors", "freestyle doors", "rear access doors", "rear-hinged doors". Suicide doors were common on cars manufactured in the first half of the 20th century; the nickname is due to the design's propensity to injure anyone exiting or entering the offside of the car if the door is hit by a passing vehicle. In the era before seat belts, the accidental opening of such doors meant that there was a greater risk of falling out of the vehicle compared to front-hinged doors, where airflow pushed the doors closed rather than opening them further. Suicide doors were popular with mobsters in the gangster era of the 1930s owing to the ease of pushing passengers out of moving vehicles, according to Dave Brownell, the former editor of Hemmings Motor News.
After World War II, the use of suicide doors was limited to rear doors of four-door sedans. The best-known use of suicide doors on post-World War II American automobiles was the Lincoln Continental 4 door convertibles and sedans and Ford Thunderbird 1967–1971 four-door sedans; the British Rover P4 cars used rear suicide doors until their demise in 1964. German Goggomobil saloons and coupes had two door bodies with suicide doors, until these were changed to front-hinged in 1964. Due to increasing safety concerns, the last mass-produced car model with independently opening suicide doors sold in the United States was the Ford Thunderbird four-door sedan from 1967 to 1971; the last mass-produced pickup truck with such doors was the Toyota Tundra from 2000 to 2002. In 2003, the new Rolls-Royce Phantom reintroduced independent suicide doors in luxury vehicle applications. Other luxury models with classic suicide doors include the Spyker D8 and the Rolls-Royce Phantom Drophead Coupe four-seat convertible.
However, the most recent mass-produced model with such doors has been the Rolls-Royce Phantom Series II introduced in 2012. In recent years, rear-hinged rear doors that cannot be opened until the front doors are opened have appeared on a number of vehicles, including extended-cab pickup trucks, the Saturn SC, the Saturn Ion Quad Coupe, the Honda Element, the Toyota FJ Cruiser, the BMW i3, the Mazda RX-8; such doors are more properly referred to as clamshell doors. Rear passenger suicide doors had long been used on Austin FX4 hackney carriages, their successors, the TX1 TX2 and TX4, lacked them. In 2018 LEVC introduced the TXe. Several concept cars have featured suicide doors, such as the Lincoln C, a hatchback with no B-pillar and rear suicide doors, or the Carbon Motors Corporation E7, a police car with rear suicide doors designed to aid officers getting handcuffed passengers in and out of the back seat; the Kia Naimo, an electric concept car has rear suicide doors. Other car manufacturers which have produced models with suicide doors include Citroën, Opel, Rover, Saturn, Škoda, Volkswagen.
Lincoln has announced that 80 limited-edition 2019 Continentals will be made with suicide doors, marking the Continental's 80th anniversary. "A limited number of additional Continental Coach Door Edition sedans will be available for the 2020 model year, too..." Rear-hinged doors make entering and exiting a vehicle easier, allowing a passenger to enter by turning to sit and exit by stepping forward and out. In combination with traditional front doors, they allow chauffeurs easier access to the rear door. In Austin FX4 taxis, drivers were able to reach the rear door handle through the driver's window without getting out of the vehicle. Additionally, rear-hinged doors allow a better position for a person installing a child seat into the back seat of a vehicle than conventional doors, while being simpler and cheaper to build than the sliding doors used on MPVs. However, the most recent MPV in the compact MPV class with such doors has been the Opel Meriva B introduced in 2010; the combination of front-hinged front doors and rear-hinged rear doors allows for a design without the B-pillar, creating a large opening for entering and exiting the vehicle as seen in the above photo.
When front doors are directly adjacent to rear suicide doors and entering the vehicle can be awkward if people try to use the front and back doors at the same time. There are a number of safety hazards: In case a person, while exiting a car from a driver side, forgets to look at traffic coming from the backside of the vehicle, if the door gets hit by a vehicle the door will hit the passenger, causing serious injury. Whereas in the case of a front-hinged door, the door swings forward, reducing possible passenger injury. Aerodynamic factors forcing rear-hinged doors open at speed in older cars. In 1969, Consumer Reports reported this problem on a Subaru 360. In recent years, car companies have addressed these hazards with such safety features as seat belts, locks requiring front-hinged doors be open before permitting rear-hinged doors to open. Butterfly doors Canopy doors Gull-wing doors List of cars with non-standard door designs Scissor doors Sliding doors Swan doors
Park Ward was a British coachbuilder founded in 1919 which operated from Willesden in North London. In the 1930s backed by Rolls-Royce Limited it made technical advances which enabled the building of all-steel bodies to Rolls-Royce's high standards. Bought by Rolls-Royce in 1939 it disappeared into the Rolls-Royce group in 1961 as a part of Mulliner-Park Ward. Park Ward was founded in 1919 by William MacDonald Park and Charles Ward, they had worked together at F. W. Berwick Limited the makers of Sizaire-Berwick cars, they built their first Rolls-Royce body in 1920. After producing bodies for a variety of cars in the early 1920s Park Ward became associated with W O Bentley's new business manufacturing their chassis nearby at Cricklewood. In 1922 they were asked by Rolls-Royce to take part in a scheme to make standard bodies for their small Twenty model but the project was abandoned though they did build bespoke bodies for Rolls-Royce customers exhibiting a 40-50 model at the British Empire exhibition in 1924.
From the mid-1920s the company started to concentrate on Rolls-Royce models. By 1930, 90% of all of Park Ward's efforts were for Rolls-RoyceAfter the Rolls-Royce take over of Bentley in 1931 Rolls-Royce took a stake in Park Ward. Beginning in 1933 when they obtained patents Park Ward developed a technically interesting all-steel saloon in conjunction with Rolls-Royce and from 1936 offered it on the 4¼-litre Bentley chassis; these bodies were supported by Silentbloc rubber bushes to reduce road-shock engine-noise and vibration. The cars were produced in small batches giving quite noticeable economies in manufacture with a consequent reduction in selling price. By 1937 as many as ten cars a week were passing through Park Ward's works and in 1939 Rolls-Royce completed its acquisition of the business. After World War II, Park Ward continued to produce special coachwork and the all-steel technology was used by Rolls-Royce to produce a standard body range on its cars starting with the Bentley Mark VI.
Twenty years Park Ward was merged with H. J. Mulliner & Co. in 1961 to form Mulliner Park Ward. Mulliner Park Ward operations were centralized in the former Park Ward factory in Willesden. In 1971 the division was retitled Rolls-Royce Motors Ltd. Captain Cuthbert W. Foster, heir to the Bird's Custard fortune, commissioned Park Ward to build a body onto his newly acquired Bugatti Royale, the fourth car chassis number 41131. Fashioned on a favorite Rolls-Royce he had owned, the car is hence known as the Foster car or Limousine Park-Ward. After being acquired in 1963 by Fritz Schlumpf from American Bugatti collector John Shakespeare, the car now resides in the Musée National de l'Automobile de Mulhouse, France alongside Ettore Bugatti's personal Royale, the Coupe Napoleon. Coachbuild.com Encyclopedia: Park Ward Design for a sedanca de ville on a Rolls-Royce Phantom III chassis with 11ft 10in wheelbase
Internal combustion engine
An internal combustion engine is a heat engine where the combustion of a fuel occurs with an oxidizer in a combustion chamber, 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 applied to pistons, turbine blades, rotor or a nozzle. This force moves the component over a distance, transforming chemical energy into useful mechanical energy; the first commercially successful internal combustion engine was created by Étienne Lenoir around 1859 and the first modern internal combustion engine was created in 1876 by Nikolaus Otto. The term internal combustion engine refers to an engine in which combustion is intermittent, such as the more familiar four-stroke and two-stroke piston engines, along with variants, such as the six-stroke piston engine and the Wankel rotary engine. A second class of internal combustion engines use continuous combustion: gas turbines, jet engines and most rocket engines, each of which are internal combustion engines on the same principle as described.
Firearms are a form of internal combustion engine. In contrast, in external combustion engines, such as steam or Stirling engines, energy is delivered to a working fluid not consisting of, mixed with, or contaminated by combustion products. Working fluids can be air, hot water, pressurized water or liquid sodium, heated in a boiler. ICEs are powered by energy-dense fuels such as gasoline or diesel fuel, liquids derived from fossil fuels. While there are many stationary applications, most ICEs are used in mobile applications and are the dominant power supply for vehicles such as cars and boats. An ICE is fed with fossil fuels like natural gas or petroleum products such as gasoline, diesel fuel or fuel oil. There is a growing usage of renewable fuels like biodiesel for CI engines and bioethanol or methanol for SI engines. Hydrogen is sometimes used, can be obtained from either fossil fuels or renewable energy. Various scientists and engineers contributed to the development of internal combustion engines.
In 1791, John Barber developed the gas turbine. In 1794 Thomas Mead patented a gas engine. In 1794, Robert Street patented an internal combustion engine, the first to use liquid fuel, built an engine around that time. In 1798, John Stevens built 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 France. The same year, the Swiss engineer François Isaac de Rivaz built an internal combustion engine ignited by an electric spark. In 1823, Samuel Brown patented the first internal combustion engine to be applied industrially. In 1854 in the UK, the Italian inventors Eugenio Barsanti and Felice Matteucci tried to patent "Obtaining motive power by the explosion of gases", although the application did not progress to the granted stage. In 1860, Belgian Jean Joseph Etienne Lenoir produced a gas-fired internal combustion engine. In 1864, Nikolaus Otto patented the first atmospheric gas engine.
In 1872, American George Brayton invented the first commercial liquid-fuelled internal combustion engine. In 1876, Nikolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, four-cycle engine. In 1879, Karl Benz patented a reliable two-stroke gasoline engine. In 1886, Karl Benz began the first commercial production of motor vehicles with the internal combustion engine. In 1892, Rudolf Diesel developed 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. At one time, the word engine meant any piece of machinery—a sense that persists in expressions such as siege engine. A "motor" is any machine. Traditionally, electric motors are not referred to as "engines". In boating an internal combustion engine, installed in the hull is referred to as an engine, but the engines that sit on the transom are referred to as motors. Reciprocating piston engines are by far the most common power source for land and water vehicles, including automobiles, ships and to a lesser extent, locomotives.
Rotary engines of the Wankel design are used in some automobiles and motorcycles. Where high power-to-weight ratios are required, internal combustion engines appear in the form of combustion turbines or Wankel engines. Powered aircraft uses an ICE which may be a reciprocating engine. Airplanes can instead use jet engines and helicopters can instead employ turboshafts. In addition to providing propulsion, airliners may employ a separate ICE as an auxiliary power unit. Wankel engines are fitted to many unmanned aerial vehicles. ICEs drive some of the large electric generators, they are found in the form of combustion turbines in combined cycle power plants with a typical electrical output in the range of 100 MW to 1 GW. The high temperature exhaust is used to superheat water to run a steam turbine. Thus, the efficiency is higher because more energy is extracted from the fuel than what could be extracted by the co