Vehicle
A vehicle is a machine designed for self-propulsion, usually to transport people, cargo, or both. The term "vehicle" typically refers to ground transport vehicles such as human-powered land vehicles, animal-powered transports, motor vehicles and railed vehicles, but more broadly also includes cable transport, watercraft, amphibious vehicles, aircraft and space vehicles.
This article primarily concerns the more ubiquitous land vehicles, which can be broadly classified by the type of contact interface with the ground: wheels, tracks, rails or skis, as well as the non-contact technologies such as maglev. ISO 3833-1977 is the international standard for road vehicle types, terms and definitions.
History
It is estimated by historians that boats have been used since prehistory; rock paintings depicting boats, dated from around 50,000 to 15,000 BC, were found in Australia. The oldest boats found by archaeological excavation are logboats, with the oldest logboat found, the Pesse canoe found in a bog in the Netherlands, being carbon dated to 8040–7510 BC, making it 9,500–10,000 years old,A 7,000 year-old seagoing boat made from reeds and tar has been found in Kuwait.
Boats were used between 4000 -3000 BC in Sumer, ancient Egypt and in the Indian Ocean.
There is evidence of camel pulled wheeled vehicles about 4000–3000 BC.
The earliest evidence of a wagonway, a predecessor of the railway, found so far was the long Diolkos wagonway, which transported boats across the Isthmus of Corinth in Greece since around 600 BC. Wheeled vehicles pulled by men and animals ran in grooves in limestone, which provided the track element, preventing the wagons from leaving the intended route.
In 200 CE, Ma Jun built a south-pointing chariot, a vehicle with an early form of guidance system.
The stagecoach, a four-wheeled vehicle drawn by horses, originated in 13th century England.
Railways began reappearing in Europe during the Late Middle Ages. The earliest known record of a railway in Europe from this period is a stained-glass window in the Minster of Freiburg im Breisgau dating from around 1350.
In 1515, Cardinal Matthäus Lang wrote a description of the Reisszug, a funicular railway at the Hohensalzburg Fortress in Austria. The line originally used wooden rails and a hemp haulage rope and was operated by human or animal power, through a treadwheel.
1769: Nicolas-Joseph Cugnot is often credited with building the first self-propelled mechanical vehicle or automobile in 1769.
In Russia, in the 1780s, Ivan Kulibin developed a human-pedalled, three-wheeled carriage with modern features such as a flywheel, brake, gear box and bearings; however, it was not developed further.
In 1783, the Montgolfier brothers developed the first balloon vehicle.
In 1801, Richard Trevithick built and demonstrated his Puffing Devil road locomotive, which many believe was the first demonstration of a steam-powered road vehicle, though it could not maintain sufficient steam pressure for long periods and was of little practical use.
In 1817, The Laufmaschine, invented by the German Baron Karl von Drais, became the first human means of transport to make use of the two-wheeler principle. It is regarded as the forerunner of the modern bicycle.
In 1885, Karl Benz built the Benz Patent-Motorwagen, the first automobile, powered by his own four-stroke cycle gasoline engine.
In 1885, Otto Lilienthal began experimental gliding and achieved the first sustained, controlled, reproducible flights.
In 1903, the Wright brothers flew the Wright Flyer, the first controlled, powered aircraft, in Kitty Hawk, North Carolina.
In 1907, Gyroplane No.I became the first tethered rotorcraft to fly. The same year, the Cornu helicopter became the first rotorcraft to achieve free flight.
In 1928, Opel initiated the Opel-RAK program, the first large-scale rocket program. The Opel RAK.1 became the first rocket car; the following year, it also became the first rocket-powered aircraft.
In 1961, the Soviet space program's Vostok 1 carried Yuri Gagarin into space.
In 1969, NASA's Apollo 11 achieved the first Moon landing.
In 2010, the number of motor vehicles in operation worldwide surpassed 1 billion, roughly one for every seven people.
Types of vehicles
There are over 1 billion bicycles in use worldwide. In 2002 there were an estimated 590 million cars and 205 million motorcycles in service in the world. At least 500 million Chinese Flying Pigeon bicycles have been made, more than any other single model of vehicle. The most-produced model of motor vehicle is the Honda Super Cub motorcycle, having sold 60 million units in 2008. The most-produced car model is the Toyota Corolla, with at least 35 million made by 2010. The most common fixed-wing airplane is the Cessna 172, with about 44,000 having been made as of 2017. The Soviet Mil Mi-8, at 17,000, is the most-produced helicopter. The top commercial jet airliner is the Boeing 737, at about 10,000 in 2018. At around 14,000 for both, the most produced trams are the KTM-5 and Tatra T3. The most common trolleybus is ZiU-9.Locomotion
Locomotion consists of a means that allows displacement with little opposition, a power source to provide the required kinetic energy and a means to control the motion, such as a brake and steering system. By far, most vehicles use wheels which employ the principle of rolling to enable displacement with very little rolling friction.Energy source
It is essential that a vehicle have a source of energy to drive it. Energy can be extracted from external sources, as in the cases of a sailboat, a solar-powered car, or an electric streetcar that uses overhead lines. Energy can also be stored, provided it can be converted on demand and the storing medium's energy density and power density are sufficient to meet the vehicle's needs.Human power is a simple source of energy that requires nothing more than humans. Despite the fact that humans cannot exceed for meaningful amounts of time, the land speed record for human-powered vehicles is, as of 2009 on a recumbent bicycle.
The energy source used to power vehicles is fuel. External combustion engines can use almost anything that burns as fuel, whilst internal combustion engines and rocket engines are designed to burn a specific fuel, typically gasoline, diesel or ethanol. Food is the fuel used to power non-motor vehicles such as cycles, rickshaws and other pedestrian-controlled vehicles.
Another common medium for storing energy is batteries, which have the advantages of being responsive, useful in a wide range of power levels, environmentally friendly, efficient, simple to install, and easy to maintain. Batteries also facilitate the use of electric motors, which have their own advantages. On the other hand, batteries have low energy densities, short service life, poor performance at extreme temperatures, long charging times, and difficulties with disposal. Like fuel, batteries store chemical energy and can cause burns and poisoning in event of an accident. Batteries also lose effectiveness with time. The issue of charge time can be resolved by swapping discharged batteries with charged ones; however, this incurs additional hardware costs and may be impractical for larger batteries. Moreover, there must be standard batteries for battery swapping to work at a gas station. Fuel cells are similar to batteries in that they convert from chemical to electrical energy, but have their own advantages and disadvantages.
Electrified rails and overhead cables are a common source of electrical energy on subways, railways, trams, and trolleybuses.
Solar energy is a more modern development, and several solar vehicles have been successfully built and tested, including Helios, a solar-powered aircraft.
Nuclear power is a more exclusive form of energy storage, currently limited to large ships and submarines, mostly military. Nuclear energy can be released by a nuclear reactor, nuclear battery, or repeatedly detonating nuclear bombs. There have been two experiments with nuclear-powered aircraft, the Tupolev Tu-119 and the Convair X-6.
Mechanical strain is another method of storing energy, whereby an elastic band or metal spring is deformed and releases energy as it is allowed to return to its ground state. Systems employing elastic materials suffer from hysteresis, and metal springs are too dense to be useful in many cases.
Flywheels store energy in a spinning mass. Because a light and fast rotor is energetically favorable, flywheels can pose a significant safety hazard. Moreover, flywheels leak energy fairly quickly and affect a vehicle's steering through the gyroscopic effect. They have been used experimentally in gyrobuses.
Wind energy is used by sailboats and land yachts as the primary source of energy. It is very cheap and fairly easy to use, the main issues being dependence on weather and upwind performance. Balloons also rely on the wind to move horizontally. Aircraft flying in the jet stream may get a boost from high altitude winds.
Compressed gas is currently an experimental method of storing energy. In this case, compressed gas is simply stored in a tank and released when necessary. Like elastics, they have hysteresis losses when gas heats up during compression.
Gravitational potential energy is a form of energy used in gliders, skis, bobsleds and numerous other vehicles that go down hill. Regenerative braking is an example of capturing kinetic energy where the brakes of a vehicle are augmented with a generator or other means of extracting energy.
Motors and engines
When needed, the energy is taken from the source and consumed by one or more motors or engines. Sometimes there is an intermediate medium, such as the batteries of a diesel submarine.Most motor vehicles have internal combustion engines. They are fairly cheap, easy to maintain, reliable, safe and small. Since these engines burn fuel, they have long ranges but pollute the environment. A related engine is the external combustion engine. An example of this is the steam engine. Aside from fuel, steam engines also need water, making them impractical for some purposes. Steam engines also need time to warm up, whereas IC engines can usually run right after being started, although this may not be recommended in cold conditions. Steam engines burning coal release sulfur into the air, causing harmful acid rain.
While intermittent internal combustion engines were once the primary means of aircraft propulsion, they have been largely superseded by continuous internal combustion engines, such as gas turbines. Turbine engines are light and, particularly when used on aircraft, efficient. On the other hand, they cost more and require careful maintenance. They can also be damaged by ingesting foreign objects, and they produce a hot exhaust. Trains using turbines are called gas turbine-electric locomotives. Examples of surface vehicles using turbines are M1 Abrams, MTT Turbine SUPERBIKE and the Millennium. Pulse jet engines are similar in many ways to turbojets but have almost no moving parts. For this reason, they were very appealing to vehicle designers in the past; however, their noise, heat, and inefficiency have led to their abandonment. A historical example of the use of a pulse jet was the V-1 flying bomb. Pulse jets are still occasionally used in amateur experiments. With the advent of modern technology, the pulse detonation engine has become practical and was successfully tested on a Rutan VariEze. While the pulse detonation engine is much more efficient than the pulse jet and even turbine engines, it still suffers from extreme noise and vibration levels. Ramjets also have few moving parts, but they only work at high speed, so their use is restricted to tip jet helicopters and high speed aircraft such as the Lockheed SR-71 Blackbird.
Rocket engines are primarily used on rockets, rocket sleds and experimental aircraft. Rocket engines are extremely powerful. The heaviest vehicle ever to leave the ground, the Saturn V rocket, was powered by five F-1 rocket engines generating a combined 180 million horsepower. Rocket engines also have no need to "push off" anything, a fact that the New York Times denied in error. Rocket engines can be particularly simple, sometimes consisting of nothing more than a catalyst, as in the case of a hydrogen peroxide rocket. This makes them an attractive option for vehicles such as jet packs. Despite their simplicity, rocket engines are often dangerous and susceptible to explosions. The fuel they run off may be flammable, poisonous, corrosive or cryogenic. They also suffer from poor efficiency. For these reasons, rocket engines are only used when absolutely necessary.
Electric motors are used in electric vehicles such as electric bicycles, electric scooters, small boats, subways, trains, trolleybuses, trams and experimental aircraft. Electric motors can be very efficient: over 90% efficiency is common. Electric motors can also be built to be powerful, reliable, low-maintenance and of any size. Electric motors can deliver a range of speeds and torques without necessarily using a gearbox. Electric motors are limited in their use chiefly by the difficulty of supplying electricity.
Compressed gas motors have been used on some vehicles experimentally. They are simple, efficient, safe, cheap, reliable and operate in a variety of conditions. One of the difficulties met when using gas motors is the cooling effect of expanding gas. These engines are limited by how quickly they absorb heat from their surroundings. The cooling effect can, however, double as air conditioning. Compressed gas motors also lose effectiveness with falling gas pressure.
Ion thrusters are used on some satellites and spacecraft. They are only effective in a vacuum, which limits their use to spaceborne vehicles. Ion thrusters run primarily off electricity, but they also need a propellant such as caesium, or, more recently xenon. Ion thrusters can achieve extremely high speeds and use little propellant; however, they are power-hungry.