A gyrobus is an electric bus that uses flywheel energy storage, not overhead wires like a trolleybus. The name comes from the Greek language term for flywheel, gyros. While there are no gyrobuses currently in use commercially, development in this area continues.
The concept of a flywheel-powered bus was developed and brought to fruition during the 1940s by Oerlikon (of Switzerland), with the intention of creating an alternative to trolleybuses for quieter, lower-frequency routes, where full overhead-wire electrification could not be justified.
Rather than carrying an internal combustion engine or batteries, or connecting to overhead powerlines, a gyrobus carries a large flywheel that is spun at up to 3,000 RPM by a "squirrel cage" motor. [1] Power for charging the flywheel was sourced by means of three booms mounted on the vehicle's roof, which contacted charging points located as required or where appropriate (at passenger stops en route, or at terminals, for instance). To obtain tractive power, capacitors would excite the flywheel's charging motor so that it became a generator, in this way transforming the energy stored in the flywheel back into electricity. Vehicle braking was electric, and some of the energy was recycled back into the flywheel, thereby extending its range.
Fully charged, a gyrobus could typically travel as far as 6 km (3.7 mi) on a level route at speeds of up to 50 to 60 km/h (31 to 37 mph), depending on the total weight of passengers, as top speeds varied as passenger levels varied from stop to stop. The installation in Yverdon-les-Bains (Switzerland) sometimes saw vehicles needing to travel as far as 10 km (6.2 mi) on one charge, although it is not known how well they performed towards the upper end of that distance.
Charging a flywheel took between 30 seconds and 3 minutes; in an effort to reduce the charge time, the supply voltage was increased from 380 volts to 500 volts. Given the relatively restricted range between charges, it is likely that several charging stops would have been required on longer routes, or in dense urban traffic. It is not clear whether vehicles that require such frequent delays would have been practical and/or suitable for modern-day service applications.
The demonstrator was first displayed (and used) publicly in summer 1950 and, to promote the system, this vehicle continued to be used for short periods of public service in myriad locations at least until 1954.
In 1979, General Electric was awarded a $5 million four-year contract by the United States government, the Department of Energy and the Department of Transportation, to develop a prototype flywheel bus. [2]
In the 1980s, Volvo briefly experimented with using flywheels charged by a small diesel engine and recharged via braking energy. This was eventually dumped in favour of using hydraulic accumulators.
During the 1990s, the Dutch Centre for Concepts in Mechatronics had developed a flywheel for both mobile and stationary applications. [3]
In 2005, the Center for Transportation and the Environment, working with the University of Texas at Austin, Center for Electromechanics, Test Devices, Inc., and DRS Technologies sought funding for the development of a prototype gyrobus. [4]
The first full commercial service began in October 1953, linking the Swiss communities of Yverdon-les-Bains and Grandson. However, this was a route with limited traffic potential, and although technically successful it was not commercially viable. Services ended in late October 1960, and neither of the two vehicles (nor the demonstrator) survived.
The next system to open was in Léopoldville in Belgian Congo (now Kinshasa in the Democratic Republic of the Congo). Here there were 12 vehicles (although apparently some reports suggest 17), which operated over four routes, with recharging facilities being provided about every 2 km (1.2 mi). These were the largest of the gyrobuses, being 10.4 m (34 ft) in length, weighing 10.9 tonnes (10.7 long tons ; 12.0 short tons ), carrying up to 90 passengers, and having a maximum speed of 60 km/h (37 mph). [5] There were major problems related to excessive "wear and tear". One significant reason for this was that drivers often took shortcuts across unpaved roads, which after rains became nothing more than quagmires. Other problems included breakage of gyro ball bearings, and high humidity resulting in traction motor overload. The system's demise, however, came because of high energy consumption. The bus operator deemed that 3.4 kWh/km per gyrobus was unaffordable, so closure came in the summer of 1959 with the gyrobuses being abandoned and replaced with diesel buses. [5]
The third location to use gyrobuses commercially was Ghent, Belgium. Three gyrobuses started operation in late summer 1956 on a route linking Ghent and Merelbeke. The flywheel was in the center of the bus, spanning almost the whole width of the vehicle, and having a vertical axis of rotation. The Ghent to Merelbeke route was intended to be the first of a proposed multi-route network; instead, its gyrobuses stayed in service for only three years, being withdrawn late autumn 1959. The operator considered them unreliable, "spending more time off the road than on", and that their weight damaged road surfaces. They were also considered to be energy hungry, consuming 2.9 kWh/km—compared with between 2.0 kWh/km and 2.4 kWh/km for trams with much greater capacity.
One of Ghent's gyrobuses has been preserved and restored, and is displayed at the VLATAM-museum in Antwerp. It is sometimes shown (and used to carry passengers) at Belgian exhibitions, transport enthusiasts' bazaars, etc. The tram depot in Merelbeke has been closed since 1998, but it still stands, as it is protected by the law.
Since 2005 Dresden, Germany has had an Autotram, a vehicle that uses a fuel cell as its main source of energy and a small flywheel for regenerative braking only. [6]
A vehicle is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles, railed vehicles, watercraft, amphibious vehicles, aircraft and spacecraft.
A trolleybus is an electric bus that draws power from dual overhead wires using spring-loaded trolley poles. Two wires, and two trolley poles, are required to complete the electrical circuit. This differs from a tram or streetcar, which normally uses the track as the return path, needing only one wire and one pole. They are also distinct from other kinds of electric buses, which usually rely on batteries. Power is most commonly supplied as 600-volt direct current, but there are exceptions.
A hybrid vehicle is one that uses two or more distinct types of power, such as submarines that use diesel when surfaced and batteries when submerged. Other means to store energy include pressurized fluid in hydraulic hybrids.
A railcar is a self-propelled railway vehicle designed to transport passengers. The term "railcar" is usually used in reference to a train consisting of a single coach, with a driver's cab at one or both ends. Some railway companies, such as the Great Western, termed such vehicles "railmotors".
An electric vehicle (EV) is a vehicle that uses one or more electric motors for propulsion. It can be powered by a collector system, with electricity from extravehicular sources, or it can be powered autonomously by a battery. EVs include, but are not limited to, road and rail vehicles, surface and underwater vessels, electric aircraft, and electric spacecraft. For road vehicles, together with other emerging automotive technologies such as autonomous driving, connected vehicles, and shared mobility, EVs form a future mobility vision called Connected, Autonomous, Shared, and Electric (CASE) Mobility.
Regenerative braking is an energy recovery mechanism that slows down a moving vehicle or object by converting its kinetic energy into a form that can be either used immediately or stored until needed. In this mechanism, the electric traction motor uses the vehicle's momentum to recover energy that would otherwise be lost to the brake discs as heat. This method contrasts with conventional braking systems. In those systems, the excess kinetic energy is converted to unwanted and wasted heat due to friction in the brakes, or with rheostatic brakes, where the energy is recovered by using electric motors as generators but is immediately dissipated as heat in resistors. In addition to improving the overall efficiency of the vehicle, regeneration can significantly extend the life of the braking system as the mechanical parts will not wear out quickly.
The Snaefell Mountain Railway is an electric mountain railway on the Isle of Man in Europe. It joins the village of Laxey with the summit of Snaefell, at 2,036 feet (621 m) above sea level the highest point on the island. It connects with the Manx Electric Railway (MER) in Laxey. The line is 5 miles (8 km) long, is built to 3 ft 6 in gauge and uses a Fell Incline Railway System centre rail for braking on the steep gradients. It is electrified using overhead wires at 550 volts direct current, with bow collectors.
Hybrid Synergy Drive (HSD), also known as Toyota Hybrid System II, is the brand name of Toyota Motor Corporation for the hybrid car drive train technology used in vehicles with the Toyota and Lexus marques. First introduced on the Prius, the technology is an option on several other Toyota and Lexus vehicles and has been adapted for the electric drive system of the hydrogen-powered Mirai, and for a plug-in hybrid version of the Prius. Previously, Toyota also licensed its HSD technology to Nissan for use in its Nissan Altima Hybrid. Its parts supplier Aisin Seiki Co. offers similar hybrid transmissions to other car companies.
A solar vehicle or solar electric vehicle is an electric vehicle powered completely or significantly by direct solar energy. Usually, photovoltaic (PV) cells contained in solar panels convert the sun's energy directly into electric energy. The term "solar vehicle" usually implies that solar energy is used to power all or part of a vehicle's propulsion. Solar power may be also used to provide power for communications or controls or other auxiliary functions.
An electric bus is a bus that is propelled using electric motors as opposed to an internal combustion engine. Electric buses can store the needed electricity on-board, or be fed continuously from an external source. The majority of buses storing electricity are battery electric buses, where the electric motor obtains energy from an onboard battery pack, although examples of other storage modes do exist, such as the gyrobus which uses flywheel energy storage. When electricity is not stored on board, it is supplied by contact with outside power sources. For example, overhead wires as in the trolleybus, or with a ground-level power supply, or through inductive charging.
Parry People Movers Ltd. (PPM) is a British company manufacturing lightweight trams and railcars that use flywheel energy storage (FES) to store energy for traction, allowing electric systems to operate without overhead wires or third rails, and railcars fuelled by small gas, diesel or hydrogen engines.
The gyro monorail, gyroscopic monorail, gyro-stabilized monorail, or gyrocar are terms for a single rail land vehicle that uses the gyroscopic action of a spinning wheel to overcome the inherent instability of balancing on top of a single rail.
The energy efficiency in transport is the useful travelled distance, of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in liquid fuels, electrical energy or food energy. The energy efficiency is also occasionally known as energy intensity. The inverse of the energy efficiency in transport, is the energy consumption in transport.
A battery electric bus is an electric bus that is driven by an electric motor and obtains energy from on-board batteries. Many trolleybuses use batteries as an auxiliary or emergency power source.
British Rail Class 139 is the TOPS classification for PPM60 model lightweight railcars built by Parry People Movers, for use on the British rail network. The class were originally built in 2008 for operation on the Stourbridge Town branch line following an extensive trial with a prototype registered as a Class 999 unit.
A kinetic energy recovery system (KERS) is an automotive system for recovering a moving vehicle's kinetic energy under braking. The recovered energy is stored in a reservoir for later use under acceleration. Examples include complex high end systems such as the Zytek, Flybrid, Torotrak and Xtrac used in Formula One racing and simple, easily manufactured and integrated differential based systems such as the Cambridge Passenger/Commercial Vehicle Kinetic Energy Recovery System (CPC-KERS).
A battery electric multiple unit (BEMU), battery electric railcar or accumulator railcar is an electrically driven multiple unit or railcar whose energy is derived from rechargeable batteries driving the traction motors.
Flywheel energy storage (FES) works by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy. When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of conservation of energy; adding energy to the system correspondingly results in an increase in the speed of the flywheel.
A capacitor electric vehicle is a vehicle that uses supercapacitors to store electricity.
Ecomechatronics is an engineering approach to developing and applying mechatronical technology in order to reduce the ecological impact and total cost of ownership of machines. It builds upon the integrative approach of mechatronics, but not with the aim of only improving the functionality of a machine. Mechatronics is the multidisciplinary field of science and engineering that merges mechanics, electronics, control theory, and computer science to improve and optimize product design and manufacturing. In ecomechatronics, additionally, functionality should go hand in hand with an efficient use and limited impact on resources. Machine improvements are targeted in 3 key areas: energy efficiency, performance and user comfort.
Media related to Gyroscope-powered buses at Wikimedia Commons
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