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
Overhead valve engine
An overhead valve engine, or "pushrod engine", is a reciprocating piston engine whose poppet valves are sited in the cylinder head. An OHV engine's valvetrain operates its valves via a camshaft within the cylinder block, cam followers and rocker arms; the OHV engine was an advance over the older flathead engine, whose valves were sited within the cylinder block. Some early "OHV" engines known as "F-heads" used both side-valves and overhead valves. A variation over the OHV design is the overhead camshaft, or "OHC", whose camshaft lies in the cylinder head itself, above the valves. To avoid confusion, OHC engines are not referred to as OHV despite having their valves in the head. In early 1894, Rudolf Diesel's second Diesel engine prototype was built with a cylinder head featuring push rods, rocker arms, poppet valves. Diesel had published this design in 1893. In 1896, U. S. patent 563,140, awarded to William F. Davis, illustrated a gasoline engine with the same head configuration, patenting his solution to the problem of how to cool the head, which problem had made the overhead valve engine difficult before then.
Henry Ford's Quadricycle of 1896 had valves in the head, with push rods for exhaust valves only, the intake using suction valves. In 1898, Detroit bicycle manufacturer Walter Lorenzo Marr built a motor-trike with a one-cylinder OHV engine with push rods for both exhaust and intake. In 1900, David Buick hired Marr as chief engineer at the Buick Auto-Vim and Power Company in Detroit, where he worked until 1902. Marr's engine employed pushrod-actuated rocker arms, which in turn pushed valves parallel to the pistons. Marr left Buick to start his own automobile company in 1902, the Marr Auto-Car, made a handful of cars with overhead valve engines, before coming back to Buick in 1904; the OHV engine was patented in 1902 by Buick's second chief engineer Eugene Richard, at the Buick Manufacturing Company, precursor to the Buick Motor Company. The world's first production overhead valve internal combustion engine was put into the first production Buick automobile, the 1904 Model B, which used a 2-cylinder Flat twin engine, with 2 valves in each head.
The engine was designed by David Buick. Eugene Richard of the Buick Manufacturing Company was awarded US Patent #771,095 in 1904 for the valve in head engine, it included rocker arms and push rods, a water jacket for the head which communicated with the one in the cylinder block, lifters pushed by a camshaft with a 2-to-1 gearing ratio to the crankshaft. Arthur Chevrolet was awarded US Patent #1,744,526 for an adapter that could be applied to an existing engine, thus transforming it into an Overhead Valve Engine; the Wright Brothers built their own airplane engines, starting in 1906, they used overhead valves for both exhaust and intake, with push rods and rocker arms for the exhaust valves only, the intake valves being "automatic suction" valves. They built a V-8 engine with this valve configuration in 1910. In 1949, Oldsmobile introduced the Rocket V8, the first V-8 engine with OHV's to be produced on a wide scale. General Motors is the world's largest pushrod engine producer, producing I4, V6 and V8 pushrod engines.
Most other companies use overhead cams. Nowadays, automotive use of side-valves has disappeared, valves are all "overhead". However, most are now driven more directly by the overhead camshaft system. Few pushrod-type engines remain in production outside of the United States market; this is in part a result of some countries passing laws to tax engines based on displacement, because displacement is somewhat related to the emissions and fuel efficiency of an automobile. This has given OHC engines a regulatory advantage in those countries, which resulted in few manufacturers wanting to design both OHV and OHC engines. However, in 2002, Chrysler introduced a new pushrod engine: a 5.7-litre Hemi engine. The new Chrysler Hemi engine presents advanced features such as variable displacement technology and has been a popular option with buyers; the Hemi was on the Ward's 10 Best Engines list for 2003 through 2007. Chrysler produced the world's first production variable-valve OHV engine with independent intake and exhaust phasing.
The system is called CamInCam, was first used in the 600 horsepower SRT-10 engine for the 2008 Dodge Viper. Early air-cooled ohv BMW boxer motorcycle engines had long pushrods and a single centrally-mounted camshaft; the pushrods were short, allowing higher rpm and more power. For instance, the BMW R1100S could achieve an output of 98 hp at 8,400 rpm, with no risk of valve bounce. Since 2013, BMW flat-twin motorcycle engines have had OHC valve actuation. OHV engines have some advantages over OHC engines: Smaller overall packaging: because of the camshaft's location inside the engine block, OHV engines are more compact than an overhead cam engine of comparable displacement. For example, Ford's 4.6 L OHC modular V8 is larger than the 5.0 L I-head Windsor V8. GM's 4.6 L OHC Northstar V8 is taller and wider than GM's larger displacement 5.7 to 7.0 L I-head LS V8. The Ford Ka uses the Kent Crossflow/Endura-E OHV engine to fit under its low bonnet line; because of the more compact size of an engine of a given displacement, a pushrod engine of given external dimensions can have greater displacement than an OHC engine of the same external size.
As a result, the pushrod engine can sometimes produce just as much power as the OHC engine, but with greater torque (contrary to popular belief, this is due to the greater displacement of
A fuel is any material that can be made to react with other substances so that it releases energy as heat energy or to be used for work. The concept was applied to those materials capable of releasing chemical energy but has since been applied to other sources of heat energy such as nuclear energy; the heat energy released by reactions of fuels is converted into mechanical energy via a heat engine. Other times the heat itself is valued for warmth, cooking, or industrial processes, as well as the illumination that comes with combustion. Fuels are used in the cells of organisms in a process known as cellular respiration, where organic molecules are oxidized to release usable energy. Hydrocarbons and related oxygen-containing molecules are by far the most common source of fuel used by humans, but other substances, including radioactive metals, are utilized. Fuels are contrasted with other substances or devices storing potential energy, such as those that directly release electrical energy or mechanical energy.
The first known use of fuel was the combustion of wood or sticks by Homo erectus nearly two million years ago. Throughout most of human history fuels derived from plants or animal fat were only used by humans. Charcoal, a wood derivative, has been used since at least 6,000 BCE for melting metals, it was only supplanted by coke, derived from coal, as European forests started to become depleted around the 18th century. Charcoal briquettes are now used as a fuel for barbecue cooking. Coal was first used as a fuel around 1000 BCE in China. With the energy in the form of chemical energy that could be released through combustion, but the concept development of the steam engine in the United Kingdom in 1769, coal came into more common use as a power source. Coal was used to drive ships and locomotives. By the 19th century, gas extracted from coal was being used for street lighting in London. In the 20th and 21st centuries, the primary use of coal is to generate electricity, providing 40% of the world's electrical power supply in 2005.
Fossil fuels were adopted during the Industrial Revolution, because they were more concentrated and flexible than traditional energy sources, such as water power. They have become a pivotal part of our contemporary society, with most countries in the world burning fossil fuels in order to produce power; the trend has been towards renewable fuels, such as biofuels like alcohols. Chemical fuels are substances that release energy by reacting with substances around them, most notably by the process of combustion. Most of the chemical energy released in combustion was not stored in the chemical bonds of the fuel, but in the weak double bond of molecular oxygen. Chemical fuels are divided in two ways. First, by their physical properties, as a solid, liquid or gas. Secondly, on the basis of their occurrence: primary and secondary. Thus, a general classification of chemical fuels is: Solid fuel refers to various types of solid material that are used as fuel to produce energy and provide heating released through combustion.
Solid fuels include wood, peat, hexamine fuel tablets, pellets made from wood, wheat and other grains. Solid-fuel rocket technology uses solid fuel. Solid fuels have been used by humanity for many years to create fire. Coal was the fuel source which enabled the industrial revolution, from firing furnaces, to running steam engines. Wood was extensively used to run steam locomotives. Both peat and coal are still used in electricity generation today; the use of some solid fuels is restricted or prohibited in some urban areas, due to unsafe levels of toxic emissions. The use of other solid fuels as wood is decreasing as heating technology and the availability of good quality fuel improves. In some areas, smokeless coal is the only solid fuel used. In Ireland, peat briquettes are used as smokeless fuel, they are used to start a coal fire. Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy producing kinetic energy, it is the fumes of liquid fuels.
Most liquid fuels in widespread use are derived from the fossilized remains of dead plants and animals by exposure to heat and pressure inside the Earth's crust. However, there are several types, such as hydrogen fuel, jet fuel and bio-diesel which are all categorized as a liquid fuel. Emulsified fuels of oil-in-water such as orimulsion have been developed a way to make heavy oil fractions usable as liquid fuels. Many liquid fuels play a primary role in the economy; some common properties of liquid fuels are that they are easy to transport, that can be handled easily. They are easy to use for all engineering applications, home use. Fuels like kerosene are rationed in some countries, for example available in government subsidized shops in India for home use. Conventional diesel is similar to gasoline in that it is a mixture of aliphatic hydrocarbons extracted from petroleum. Kerosene is used in kerosene lamps and as a fuel for cooking and small engines. Natural gas, composed chiefly of methane, can only exist as a liquid at low temperatures, which limits its direct use as a liquid fuel in most applications.
LP gas is a mixture of propane and butane, both of which are compressible gases under standard atmospheric conditions. It offers many of the advantages of compressed natural gas (CN
A valvetrain or valve train is a mechanical system that controls operation of the valves in an internal combustion engine, whereby a sequence of components transmits motion throughout the assembly. A conventional reciprocating internal combustion engine uses valves to control the flow of the air/fuel admix into and out of the combustion chamber. A typical ohv valvetrain consists of valves, rocker arms, pushrods and camshaft. Valvetrain opening/closing and duration, as well as the geometry of the valvetrain, controls the amount of air and fuel entering the combustion chamber at any given point in time. Timing for open/close/duration is controlled by the camshaft, synchronized to the crankshaft by a chain, belt, or gear. Valvetrains are built in several configurations, each of which varies in layout but still performs the task of opening and closing the valves at the time necessary for proper operation of the engine; these layouts are differentiated by the location of the camshaft within the engine: Cam-in-block The camshaft is located within the engine block, operates directly on the valves, or indirectly via pushrods and rocker arms.
Because they require pushrods they are called pushrod engines. Overhead camshaft The camshaft is located above the valves within the cylinder head, operates either indirectly or directly on the valves. Camless This layout uses no camshafts at all. Technologies such as solenoids are used to individually actuate the valves; the valvetrain is the mechanical system responsible for operation of the valves. Valves are of the poppet type, although many others have been developed such as sleeve and rotary valves. Poppet valves require small coil springs, appropriately named valve springs, to keep them closed when not actuated by the camshaft, they are attached to the valve stem ends, seating within spring retainers. Other mechanisms can be used in place of valve springs to keep the valves closed: Formula 1 engines employ pneumatic valve springs in which pneumatic pressure closes the valves, while motorcycle manufacturer Ducati uses desmodromic valve drive which mechanically close the valves. Depending on the design used, the valves are actuated directly by a rocker arm, finger, or bucket tappet.
Overhead camshaft engines use fingers or bucket tappets, upon which the cam lobes contact, while pushrod engines use rocker arms. Rocker arms are actuated by a pushrod, pivot on a shaft or individual ball studs in order to actuate the valves. Pushrods are slender metal rods seated within the engine block. At the bottom ends the pushrods are fitted with lifters, either solid or hydraulic, upon which the camshaft, located within the cylinder block, makes contact; the camshaft pushes on the lifter, which pushes on the pushrod, which pushes on the rocker arm, which rotates and pushes down on the valve. Camshafts must actuate the valves at the appropriate time in the combustion cycle. In order to accomplish this the camshaft is linked to and kept in synchronisation with the crankshaft through the use of a metal chain, rubber belt, or geartrain; because these mechanisms are essential to the proper timing of valve actuation they are named timing chains, timing belts, timing gears, respectively. Typical normal-service engine valve-train components may be too lightweight for operating at high revolutions per minute, leading to valve float.
This occurs when the action of the valve no longer opens or closes, such as when the valve spring force is insufficient to close the valve causing a loss of control of the valvetrain, as well as a drop in power output. Valve float will damage the valvetrain over time, could cause the valve to be damaged as it is still open while the piston comes to the top of its stroke. Upgrading to high pressure valve springs could allow higher valvetrain speeds, but this would overload the valvetrain components and cause excessive and costly wear. High-output and engines used in competition feature camshafts and valvetrain components that are designed to withstand higher RPM ranges; these changes include additional modifications such as larger-sized valves combined with freer breathing intake and exhaust ports to improve air flow. Automakers offer factory-approved performance parts to increase engine output, numerous aftermarket parts vendors specialize in valvetrain modifications for various engine applications.
Cam-in-block Overhead camshaft Camless Animation
Le Train Bleu
The Calais-Mediterranée Express was a luxury French night express train which operated from 1886 to 2003. It gained international fame as the preferred train of wealthy and famous passengers between Calais and the French Riviera in the two decades before World War II, it was colloquially referred to as Le Train Bleu in French and the Blue Train in English because of its dark blue sleeping cars. In December 1883 the Compagnie Internationale des Wagons-Lits created its second luxury train after the Orient Express introduced in June earlier that year. Due to contracts between CIWL's competitor Pullman and the owner of the Mont Cenis Railway, the Società per le strade ferrate dell'Alta Italia, CIWL could not use the Fréjus Rail Tunnel, so CIWL was forced to use the longer route along the Mediterranean coast; the connection between Paris and Rome was introduced as Calais Nice Rome Express, but was reduced to Calais Nice Express after only one year. In 1885 several Italian railways merged and CIWL could buy the routes served by Pullman, which made it possible to use the shorter Mont Cenis Railway.
The train was to be named Rome Express. In order to serve the British customers the Calais-Mediterranée Express was created in 1886, but it lasted until 1890 before the Rome Express made its first journey; the Calais-Méditerrannée Express was introduced in the 1886/1887 winter timetable. In the winter of 1889/1890 the name was changed to Méditerrannée Express, due to the creation of the Club train. At the southern end the route was extended to San Remo, but the portion north of Paris was taken over by the Club Train. After the introduction of the Rome Express on 15 November 1890, the two trains were combined between Paris and Mâcon. South of Mâcon the Rome Express continued during the night over the Mont Cenis railway and the Méditerrannée Express ran through the Rhone valley to the Côte d'Azur. After several breaches of contract by CIWL the London Chatham & Dover Railway cancelled the contract, it lasted until 1926 before a new integrated boattrain service was created as Golden Arrow; the Méditerrannée Express' northern terminus was Calais again.
The service was suspended at the beginning of the First World War. The train bleu service resumed on 16 November 1920 between Paris and Menton with pre-war carriages, operated by the Compagnie Internationale des Wagons-Lits using the Chemins de fer de Paris à Lyon et à la Méditerranée. Or PLM; the whole route was served again on 9 December 1922. The new Calais-Méditerrannée Express was composed of first-class, new steel carriages built by Leeds Forge Company in England and the CIWL-works in Munich and a dining car renowned for its haute cuisine five-course dinners; the "introduction ride" was made by two trains with many invitees and nearly 50 journalists, departing from Calais and Paris bound for Nice. The sleeping cars were painted blue with gold trim; this led to the nickname Blue Train in 1923. This name was taken over soon in English advertisements: "Summer on the French Riviera by the Blue Train"; the height of the season for le train bleu was between November and April, when many travellers escaped the British winter to spend time on the French Riviera.
Its terminus was at the Gare Maritime in Calais, where it picked up British passengers from the ferries across the English Channel. It departed at 1:00 in the afternoon and stopped at the Gare du Nord in Paris travelled around Paris by the Chemin de fer de Petite Ceinture to the Gare de Lyon, where it picked up additional passengers and coaches, it departed Paris early in the evening, made stops at Dijon, Châlons, Lyon, before reaching Marseilles early the next morning. It made further stops at all the major resort towns of the French Riviera, or Côte d'Azur: Saint-Raphaël, Juan-les-Pins, Cannes, Monte-Carlo, before reaching its final destination, near the Italian border; the sleeping cars had only ten sleeping compartments each, with one attendant assigned to each sleeping car. Early passengers included the Prince of Wales, Charlie Chaplin, designer Coco Chanel, Winston Churchill and writers F. Scott Fitzgerald, Evelyn Waugh and Somerset Maugham; the Great Depression and the devaluation of the Pound Sterling reduced the number of wealthy British and American travellers going to the Riviera, reducing the two trains to two carriages conveyed with the Golden Arrow between Calais and Paris.
After a one and half hour stop the two luxury cars were conveyed further south by the Côte d'Azur Pullman Express. In 1936, the new Popular Front Government in France introduced the paid two-week vacation for French workers. Second-class and third-class sleeping cars were added to the Blue Train to carry middle and working class French people on holiday to the South of France. In 1938, the Popular Front government nationalized the private railway companies in France, including PLM. After 1938, le train bleu was run by the new French national railway company SNCF as an ordinary night express train. Service was interrupted during the Second World War but resumed in 1949, when the train took the name Le Train Bleu. Scheduled airline service began between Paris and Nice in 1945, which took away much of the wealthy clientele. In 1962 the rollingstock was replaced by MU coaches and second class coaches were introduced in the Blue Train. In 1971 the CIWL sold its rolling stock to the national railway companies that operated the trains further on.
After 1978, the train added cars with couchettes to attract more middle-class passengers. Beginning in the 1980s the night express trains were replaced by the high-speed TGV trains, which cut the length of the journey from Paris to Nice from 20 hours to five, th
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