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{{Seealso|Electric bus}}
A
Gyrobus is an
electric busAn electric bus is a bus powered by electricity.There are two main electric bus categories:* The trolleybus is a type of electric bus powered by two overhead electric wires, with electricity being drawn from one wire and returned via the other wire, using two roof-mounted trolley poles.* The...
that uses
flywheel energy storageFlywheel energy storage works by accelerating a rotor to a very high speed and maintaining the energy in the system as rotational energy...
, not overhead wires like a
trolleybusA trolleybus is an electric bus that draws its electricity from overhead wires using spring-loaded trolley poles...
. The name comes from the
Greek languageGreek , an independent branch of the Indo-European family of languages, is the language of the Greeks. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. In its ancient form, it is the language of classical...
term for
flywheelA flywheel is a mechanical device with a significant moment of inertia used as a storage device for rotational energy. Flywheels resist changes in their rotational speed, which helps steady the rotation of the shaft when a fluctuating torque is exerted on it by its power source such as a...
,
gyros.
While there are no gyrobuses currently in use commercially, development in this area continues.
Development
The concept of a flywheel powered
busA bus is a road vehicle designed to carry passengers. A bus seats a maximum of 8 to 300 passengers...
was developed and brought to fruition during the 1940s by Oerlikon (of
SwitzerlandSwitzerland , officially the Swiss Confederation , is a federal republic consisting of 26 states named cantons, with Bern as the seat of the federal authorities...
), with the intention of creating an alternative to battery-electric buses for quieter, lower-frequency routes, where full overhead-wire electrification could not be justified.
Rather than carrying an
internal combustion engineThe internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine the expansion of the high temperature and pressure gases, which are produced by the combustion, directly applies force to a movable...
or
batteriesAn electrical battery is a combination of one or more electrochemical cells, used to convert stored chemical energy into electrical energy. Since the invention of the first Voltaic pile in 1800 by Alessandro Volta, the battery has become a common power source for many household and industrial...
, 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. 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 6km on a level route at speeds of up to 50 to 60 km/h, depending on vehicle batch (load), as top speeds varied from batch to batch. The installation in
Yverdon-les-BainsYverdon-les-Bains is a municipality in the district of Yverdon of the canton of Vaud in Switzerland. It is the seat of the district...
(
SwitzerlandSwitzerland , officially the Swiss Confederation , is a federal republic consisting of 26 states named cantons, with Bern as the seat of the federal authorities...
) sometimes saw vehicles needing to travel as far as 10 km 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 a myriad of locations at least until 1954.
In 1979,
General ElectricThe General Electric Company, or GE , is a multinational American technology and services conglomerate incorporated in the State of New York. In 2009, Forbes ranked GE as the world's largest company...
was awarded a $5 million four year contract by the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
government, the
Department of EnergyThe United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...
and the
Department of TransportationThe United States Department of Transportation is a federal Cabinet department of the United States government concerned with transportation. It was established by an act of Congress on October 15, 1966 and began operation on April 1, 1967...
, to develop a prototype flywheel bus.
In the 1980s,
VolvoThe Volvo Group is a Swedish supplier of commercial vehicles such as trucks, buses and construction equipment, drive systems for marine and industrial applications, aerospace components and financial services...
briefly experimented with using flywheels charged by a small
Diesel engineA diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber during the final stage of compression...
and recharged via braking energy. This was eventually dumped in favor of using hydraulic accumulators.
During the 1990s, CCM have developed a flywheel for both mobile and stationary applications.
In 2005, the Center for Transportation and the Environment, working with the
University of Texas at AustinThe University of Texas at Austin is a public research university located in Austin, Texas, United States, and is the flagship institution of The University of Texas System. The main campus is located approximately from the Texas State Capitol...
, Center for Electromechanics, Test Devices, Inc., and DRS Technologies sought funding for the development of a prototype gyrobus.
Early commercial service
The first full commercial service began in October 1953, linking the Swiss communities of
Yverdon-les-BainsYverdon-les-Bains is a municipality in the district of Yverdon of the canton of Vaud in Switzerland. It is the seat of the district...
and
GrandsonGrandson is a municipality in the district of Grandson in the canton of Vaud in Switzerland.During the Burgundian Wars, Charles the Bold was defeated near here in the Battle of Grandson on 2 March 1476.-Geography:...
. 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 CongoThe Belgian Congo was the formal title of present-day Democratic Republic of the Congo between King Leopold II's formal relinquishment of personal control over the state to Belgium on 15 November 1908, and the dawn of Congolese independence on 30 June 1960.-Background: 1884-1908:Until the later...
(currently
Kinshasa{{clear}}{{clear}}{{clear}}{{clear}}{{clear}}{{clear}}{{Infobox settlement|name = Kinshasa|official_name =|other_name = formerly Léopoldville or Leopoldstad...
in the
Democratic Republic of the CongoThe Democratic Republic of the Congo is a country located in Central Africa, with a small length of Atlantic coastline. It is the third largest country in Africa...
). Here there were 12 vehicles (although apparently some reports erroneously suggest 17), which operated over four routes, with recharging facilities being provided about every 2 km. These were the largest of the gyrobuses, being 10.4 m in length, weighing 10.9 tonnes, carrying up to 90 passengers, and having a maximum speed of 60 km/h (about 37 mph).
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.
The third location to use gyrobuses commercially was
GhentGhent is a city and a municipality located in the Flemish region of Belgium. It is the capital and biggest city of the East Flanders province. The city started as a settlement at the confluence of the Rivers Scheldt and Lys and in the Middle Ages became one of the largest and richest cities of...
,
BelgiumThe Kingdom of Belgium is a country in northwest Europe. It is a founding member of the European Union and hosts its headquarters, as well as those of other major international organizations, including NATO...
. Three gyrobuses started operation in late summer 1956 on a route linking Ghent and
MerelbekeMerelbeke is a municipality located in the Flemish province of East Flanders, in Belgium. The municipality comprises the villages of Bottelare, Lemberge, Melsen, Merelbeke proper, Munte and Schelderode. On January 1, 2006, Merelbeke had a total population of 22,353. The total area is 36.65 km²...
(the route Gent Zuid - 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 - 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||-||-||-||}Antwerp is a city and municipality in Belgium and the capital of the Antwerp province in Flanders, one of Belgium's three regions. Antwerp's total population is 472,071 and its total area is , giving a population density of 2,308 inhabitants per km²...
. 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.
Advantages
- Quiet
- "Pollution free" (Pollution confined to generators on electric power grid)
- Runs without rails (Once thought of as an advantage because the route could be varied at will)
- Can operate flexibly at varying distances
Disadvantages
- Weight: a bus which can carry 20 persons and has range of 20 km requires a flywheel weighing three tonnes.
- The flywheel, which turns at 3000 revolutions per minute, requires special attachment and security—because the external speed of the disk is 900 km/h.
- Driving a gyrobus has the added complexity that the flywheel acts as a gyroscope
A gyroscope is a device for measuring or maintaining orientation, based on the principles of angular momentum. A mechanical gyroscope is essentially a spinning wheel or disk whose axle is free to take any orientation...
that will resist changes in orientation, for example when a bus tilts while making a turn, assuming that the flywheel has a vertical rotation axis.
External links
- Electric buses in citytransport.info - with a photograph showing two gyrobuses at a charging point http://citytransport.info/NotMine/Reed001a.jpg.
- Buses Worldwide - some of the information contained in this article comes from the January / February 2005 issue of "BusesWorldWide" Magazine as issued by the organisation of the same name.
- Technology in Parry People Movers—shows how the same technology is being transferred to ultralight Tram
A tram, tramcar, trolley, trolleycar, or streetcar is a railborne vehicle, of lighter weight and construction than a conventional train, designed for the transport of passengers within, close to, or between villages, towns and/or cities, on tracks running primarily on streets...
s
{{Buses}}