Motorized bicycle
From Wikipedia, the free encyclopedia
A motorized bicycle, sometimes referred to as a light electric vehicle or LEV, is a bicycle with an attached motor used to assist with pedaling. Generally considered to be a vehicle, sometimes as a motor vehicle or a class of hybrid vehicle, motorized bicycles are usually powered by electric motors or small internal combustion engines. Some can be propelled by the motor alone if the rider chooses not to pedal, while in others the motor will only run if the rider pedals.
Some early motorized bicycles were powered by internal combustion engines whereas some utilized electric motors. With lighter batteries and better storage density, the electric motor has recently seen an increase in popularity.
Motorized bicycles are distinguished from motorcycles by being capable of being powered by pedals alone if required. The actual usage of the pedals varies widely according to the type of vehicle. Those known as mopeds mostly have pedals for emergency use or because of legal requirements and these are not normally used. Those known as power-assist bikes have the pedals as the main form of propulsion with the motor used to give a bit of extra speed, especially uphill. Many motorized bicycles are based on standard bicycle frame designs and technologies, although the modifications to the design to support motorization may be extensive.
In countries where there is a strong bicycle culture (notably in Asia), the motorized bicycle is particularly popular; in 1996 Shanghai had 370,000 motorized bicycles and 470,000 other vehicles.[1]
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[edit] History
- For history of the bicycle in general, see History of the bicycle
- See also Timeline of motorized bicycle history
The two-wheeled pedal powered bicycle was first conceived in Paris in the 1860s. By 1888 John Dunlop invented pneumatic tires and the chain drive making possible the safety bicycle, giving the bicycle its modern form.
[edit] Electric bicycle history
In the 1890s, electric bicycles were documented within various U.S. patents. For example, on 31 December 1895 Ogden Bolton Jr. was granted U.S. Patent 552,271 for a battery-powered bicycle with “6-pole brush-and-commutator direct current (DC) hub motor mounted in the rear wheel.” There were no gears and the motor could draw up to 100 amperes (A) from a 10-V battery.[1]
Two years later, in 1897, Hosea W. Libbey of Boston invented an electric bicycle (U.S. Patent 596,272) that was propelled by a “double electric motor.” The motor was designed within the hub of the crankshaft axle.[2] This model was later re-invented and imitated in the late 1990s by Giant Lafree electric bicycles.
By 1898 a rear wheel drive electric bicycle, which used a driving belt along the outside edge of the wheel was patented by Mathew J. Steffens. Also, the 1899 U.S. Patent 627,066 by John Schnepf depicted a rear wheel friction “roller-wheel” style drive electric bicycle.[3] Schnepf's invention was later re-examined and expanded in 1969 by G.A. Wood Jr. with his U.S. Patent 3,431,994. Wood’s device used 4 fractional horsepower motors; each rated less than ½ horsepower and connected through a series of gears.[4]
Torque sensors and power controls were developed in the late 1990s. For example, Takada Yutky of Japan filed a patent in 1997 for such a device. In 1992 Vector Services Limited offered and sold an electric bicycle dubbed Zike.[5] The bicycle included Nickel-cadmium batteries that were built into a frame member and included an 850 g permanent-magnet motor. Despite the Zike, in 1992 hardly any commercial electric bicycles were available. It wasn’t until 1998 when there were at least 49 different bikes. Production grew from 1993 to 2004 by an estimated 35%. By Contrast, according to Gardner, in 1995 regular bicycle production decreased from its peak 107 million units. Some of the less expensive electric bicycles used bulky lead acid batteries, whereas newer models generally used NiMH, NiCd and/or Li-ion batteries which offered lighter, denser capacity batteries. The end benefits usually varied from manufacturer; however, in general there was an increase in range and speed. By 2004 electric bicycles where manufactured by Currie Technologies, EV Global, Optibike, Giante Lite, Merida, ZAP.
By 2001 the terms, E-Bikes, power bike, pedelec, assisted bicycle and power-assisted bicycle where commonly used to describe electric bicycles. E-bike, according to Google, is a term that has increased in trend. This term generally referred to an electric bicycle which used a throttle. The terms Electric Motorbike or E-Motorbike have been used to describe more powerful models which attain up to 80km/h.
In a parallel hybrid motorized bicycle, such as the afformentioned 1897 invention by Hosea W. Libbey, man and machine are mechanically coupled either in the bottom bracket, the rear or the front wheel, whereas in a Series Hybrid Cycles the user propels a generator using the pedals. In series hybrid cycles human power is converted into electricity and is fed directly into the motor.
Pedelec is a European term that generally referred to an electric bicycle that incorporated a torque sensor and/or a power controller that delivered a proportionate level of assist and only ran when the rider pedaled. On the opposite side, a Noped is a term used by the Ministry of Transportation of Ontario for similar type vehicles which do not have pedals or to whome the pedals have been removed from their motorized bicycle. Finally, Assist Bicycle is the technical term used to describe such a vehicle and Power-Assisted Bicycle is used in the Canadian Federal Legislation, but is carefully defined to only apply to electric motor assist, and specifically excludes internal combustion engines (though this is not the case in the United States).
These days, China is the world's leading producer of electric bicycles. According to the data of the China Bicycle Association, a government-chartered industry group, in 2004 China's manufacturers sold 7.5 million electric bicycles nationwide, which was almost twice the year 2003 sales;[2] domestic sales reached 10 million in 2005, and 16 to 18 million in 2006.[3] By 2007, electric bicycles were thought to make up 10 to 20 percent of all two-wheeled vehicles on the streets of many major cities.[3] A typical unit requires 8 hours to charge the battery, which provides the range of 25-30 miles (40-50 km),[3] at the speed of around 20 km/h.[2]
A large number of such vehicles is exported from China as well (3 million units, worth 40 billion yuan ($5.8 billion), in the year 2006 alone),[4]
[edit] Other motorized bicycles
The origins of the motorized bicycle can be traced back to the latter part of the 19th century when experimenters began attaching steam engines to stock tricycles and quadracycles.[citation needed] This moved into attempts to fit the newly-invented internal combustion engine (ICE) to the bicycle form.[5]
Development diverged into two distinct streams: motorcycles, which are powered solely by their engines, and motorized bicycles as defined above. The closeness of the two forms in early years is demonstrated by Félix Millet's machines of 1892/93 and on. These had both pedals and an ingenious fixed crankshaft radial engine built into the back wheel. Within a few years motorized bicycles and motorcycles were recognisably divergent, with for example early motorcycles being longer, heavier and with a markedly different riding position from that of a contemporary pedal cycle. Later, development forked again with the advent of mopeds, small motorcycles fitted with pedals that can be used as a starting aid but which cannot, practically, be ridden under pedal power alone. This development appears to have been largely in order to exploit ambiguities between the regulatory framework for bicycles, powered bicycles and motorcycles - in jurisdictions where pedals were not required to meet the legal framework they were often simply omitted on otherwise identical models.
In the case of motorized bicycles, too, there were soon two parallel streams of development: motor assistance as an addition to existing machines, and purpose-built motor-assisted bicycles like the Derny and VéloSoleX, with stronger frames and sometimes with only token ability to be wholly human powered. In these cases some assert that the product is more formally a motorcycle or moped than a motorized bicycle, and some jurisdictions also take this view.
The gasoline-powered motorized bicycle gained notable popularity in France during the 1930s, and continued to be widely sold in early postwar years as a means of transportation during a period of gasoline shortages and limited automobile production.
Modern motorized bicycles follow both trends, with conversions being applied by hobbyists as well as commercial manufacturers. Hub motors in particular facilitate after market conversion, being built into the wheel and not requiring modifications to the drivetrain or frame, as well as having a low centre of gravity. Converting bicycles or tricycles has proven useful for some people with physical disabilities such as arthritis. The strength of tricycles is that they will balance even while stationary, but some people find it harder to ride a tricycle and claim it lacks agility. Portability is also compromised compared to bicycles.
The modern electric bicycle is true to the concept of a pedal bicycle with assisting propulsion, being ridable without power. Batteries have finite capacity, which means that the hybrid human / electric power mix is much more likely to be emphasised than is the case with an ICE. Electric bicycles are gaining acceptance, especially in Europe and Asia, in response to increasing traffic congestion, an aging population and concern about the environment. Electric vehicle conversion – converting conventionally-powered vehicles to electric or hybrid vehicles – is also increasingly common.
Motorized bicycles' popularity has waxed and waned largely in response to local regulatory requirements. For example, the French "vélomoteur" could be ridden by young riders without need for a license, making it very popular during the 1960s and 1970s.
Autocycle manufacturers were well established in countries such as Britain and Australia before the second world war, but the hiatus of the war appears to have set the market back, although the American bolt-on Whizzer continued until 1962. The motorized bicycle saw a resurgence of popularity in Britain during the 1950s and such bolt-on motors as the Cyclaid and the Cyclemaster motor wheel saw brief periods of immense popularity. The Cyclemaster, which was a hub motor which could be fitted to an ordinary bike, started at 25cc (painted black), but later the size went up to 32cc (painted grey). Elsewhere in Europe the motorized bicycle continued to be popular. The Italian, Vincenti Piatti had designed a 50 cc engine for driving portable lathes and this was also used to in the form of the Mini Motore to power bicycles. Piatti later licensed the design to Trojan for production in Britain as the Trojan Minimotor. Production of The French VELOSOLEX began in 1946 and continued until 1988. After French production ceased, the VELOSOLEX continued to be produced in China and Hungary. In 2003 production ceased in Hungary. Today production continues in China and has restarted in France. Velosolex America is the company that markets the VELOSOLEX worldwide.
Currently there are several companies manufacturing aftermarket Internal Combustion (IC) motorisation kits for Bicycles. These include both 4-Stroke and 2-Stroke. Notably there was also a Compression-Ignition engine kit produced using an 18 cc variable head engine - this was made by Lohmann in Germany.
Current manufacturers include Golden Eagle Bike Engines using a rack mounted belt drive, Stanton who use a rack mount with a chain drive geared transmission , and various similar kits using 49/60/70cc 2-stroke engines made to have the engine centrally frame mounted in a position echoing that of Motorbikes (again generally using chain drive, or in the case of Whizzer, a belt drive. Companies marketing the latter types include Dax, Spooky Tooth Cycles and Kings. These generally have a top speed of between 25 mph (40 km/h) and 40 mph (64 km/h) (using aftermarket tuning and higher gearing ratios).
[edit] Naming and legal status
The legal definition and status of motorized bicycles varies by jurisdiction. Legal terms for motorized bicycles include "Power Assisted Bicycle (PAB)" (Canada), MOPED, "Electrically assisted pedal cycle (EAPC)" (United Kingdom), or (commonly) "electric bicycle", frequently abbreviated as "ebike". In comparison some custom designs of electric bike have a range of up to 40 miles (64 km) and a maximum speed of +55 mph (89 km/h).
It is possible to register a Cyclemotor or motorized bike for legal use on the UK's roads.[citation needed] If the machine is from a known manufacturer such as Rudge or Francis-Barnett this is a fairly simple procedure.[citation needed] It becomes much more complicated if this is not the case with current law requiring an SVA (Single Vehicle Approval) test for each individual machine.[citation needed]
In the United States low-speed electric bicycles (top speed under 20 mph and under 50 cc's or in the case of electric models 750 watts) are not considered motor vehicles by the federal government and are subject to the same consumer safety laws as unassisted bicycles[6]. Their legality on public roads is under state jurisdiction, and varies; see the main Electric bicycle laws article for details on the law in individual states.
Eight provinces of Canada allow electric power assisted bicycles. The province of Ontario introduced a three-year trial ending October 2009 for these bicycles. In seven of the eight provinces, e-bikes are limited to 500W output, and cannot travel faster than 32 km/h (20 mph) on motor power alone on level ground. In Alberta the maximum output is 750W, and the max speed is 35 km/h[6]. Age restrictions vary in Canada. All require an approved helmet. Some versions (e.g., if capable of operating without pedalling) of e-bikes require drivers' licenses in some provinces and have age restrictions. Vehicle licenses and liability insurance are not required. E-bikes are required to follow the same traffic regulations as regular bicycles. The rules for bicycles assisted by a gasoline motor or other fuel are not included in the regulations government ebikes. These are classified as motor cycles regardless of the power output of the motor and maximum attainable speed.
Generally they are considered vehicles (like motorcycles and pedal cycles), so are subject to the same rules of the road. In a few jurisdictions, motorized bicycles must be licensed and display vehicle registration plates. Regulations may define maximum power output and for electric bikes may or may not require an interlock to prevent use of power when the rider is not pedalling. In some cases regulatory requirements have been complicated by lobbying in respect of the Segway HT.
[edit] Power sources
Historically, internal combustion (IC) engines dominated the motorized bicycle market,and they still do. Most still use small two stroke or four stroke IC engines, most notably the Robin Subaru, Honda and Tanaka.
Power can be applied in a number of ways:
- the front or rear wheel may be powered via a motor built into the hub (e.g. Powabyke, Heinzmann, Crystalyte, Singer Motor Wheel)
- a motor mounted in the frame (called a frame mount) or behind the rider (called a rack mount) may drive the rear wheel with a chain or rubber belt (e.g. Staton, Golden Eagle Bike Engine (Kevlar belt rack mount), Whizzer and in Europe Derny. Most of these bikes and kits are under 50 cc's and do not have to be registered in most states (the exception being the Whizzer NE5).
- power may be transferred to one or other wheel from a motor mounted directly above, by bringing a powered roller or rubber belt into contact with the tire (e.g. Staton, BMP, and in Europe Zeta). These are called "friction drive".
- the bicycle's chain may be driven by a sprocket (pedelec bikes such as the Giant Twist/LaFree) which may force the rider to pedal or incorporate a ratchet allowing either pedalling or powering or both. (e.g. Ecospeed)
[edit] Internal combustion
The 1900 Singer Motor Wheel was a wheel incorporating a small IC engine that could be substituted for the front wheel of a bicycle, while the 1914 Smith Motor Wheel was attached to the rear of a bicycle by means of an outrigger arm, a design later taken up by Briggs & Stratton.
The VéloSoleX, probably the last large-scale IC-powered motorized bicycle, used friction drive to the front wheel. The last volume manufactured in-wheel IC engine was used on the Honda P50 moped which ceased production around 1968.
Tanaka bolt-on bike motors (branded Bike Bug, Aqua Bug, Tas Spitz, Sears Free Spirit, and Little Devil) were popular through the 1960s and 1970s, and are gaining a renewed following thanks to superior clean efficient "Pure Fire" line of 2 stroke motors.
In the late-2000s, the RevoPower Wheel returned to a concept similar to the 1900 Singer Motor Wheel, again providing an engine that would go in place of the ordinary front wheel of the bicycle to provide extra power. As of yet this has not gone into production.
[edit] Electric
There are many possible types of electric motorized bicycles with several technologies available, varying in cost and complexity; direct-drive and geared motor units are both used. An electric power-assist system may be added to almost any pedal cycle using chain drive, belt drive, hub motors or friction drive. The power levels of motors used are influenced by available legal categories and are often limited to 250 W or 450 W, however there are some much higher power drives available [7].
Electric bicycles use rechargeable batteries, electric motors and some form of control. This can be a simple as an on-off switch but is more usually an electronic pulse width modulation control. Electric bicycles developed in Switzerland in the late 1980s for the Tour de Sol solar vehicle race came with solar charging stations but these were later fixed on roofs and connected so as to feed into the electric mains. [8] The bicycles were then charged from the mains, as is common today. Battery systems in use include lead-acid, NiCd, NiMH and Li-ion batteries.
Electric motorized bicycles can be power-on-demand, where the motor is activated by a handlebar mounted throttle, and/or a pedelec (from pedal electric), also known as electric assist, where the electric motor is regulated by pedalling. These have a sensor to detect the pedalling speed, the pedalling force, or both. An electronic controller provides assistance as a function of the sensor inputs, the vehicle speed and the required force. Most controllers also provide for manual adjustment.
Range is a key consideration with electric bikes, and is affected by factors such as motor efficiency, battery capacity, efficiency of the driving electronics, aerodynamics, hills and weight of the bike and rider. The range of an electric bike is usually stated as somewhere between 7km (uphill on electric power only) to 70km (minimum assistance). Some manufacturers, such as the Canadian BionX, have the option of using regenerative braking, the motor acts as a generator to slow the bike down prior to the brake pads engaging.[9] This is useful for extending the range and the life of brake pads and wheel rims. There are also experiments using fuel cells. e.g. the PHB.
The energy costs of operating electric bicycles are small, but there can be considerable battery replacement costs.
[edit] Other power sources
- For history of steam cycles, see steam tricycle
Individuals have built bicycles powered by steam and air engines, and there are many known jet propelled bicycles. No large-scale manufacture of any of these is known (though jet powered bicycles are commonly created by hobbyist as seen in hundreds of homemade videos on websites Google Video and Youtube).[citation needed]
Some experiments have also been undertaken with super capacitors to supplement or replace batteries for cars and some SUVS.
[edit] Environmental effects
The environmental effects of motorized bicycles varies according to the power source.
Old inefficient Two stroke engines, common in those powered by internal combustion engines ("Happy Time" made-in-China two strokes are still dirty like the old ones) , often emitted more pollution than automobiles due to partial combustion of the upper cylinder lubricant necessarily included in the fuel (this is not the case with newer 2 stroke motors such as the Tanaka "Pure Fire"). One Swedish study found that running the older inefficient 2-stroke lawnmower for half an hour pollutes as much as a 150 km trip in an average car.[10]. Fortunately those older two strokes are not in common usage on motorized bicycles having been replaced by super clean four stoke engines (such as the Robin Subaru EHO35 and EHO25), and clean two strokes such as the Tanaka (Pure fire) engines.
While most electric bicycles can be classified as zero-emissions vehicles, as they emit no combustion byproducts, the environmental effects of electricity generation and power distribution and of manufacturing and disposing of (limited life) high storage density batteries must be taken into account. Even with these issues considered, electric bicycles will have significantly lower environmental impact than conventional automobiles, and are generally seen as environmentally desirable in an urban environment, as are the newer internal combustion engines which do not have the substantial environmental problem of battery disposal.
The environmental credentials of electric bikes, and electric / human powered hybrids generally, have led some municipal authorities to use them, such as Little Rock, Arkansas with their Wavecrest electric power-assisted bicycles or Cloverdale, California police with Zap electric bicycles.[11]
[edit] Bibliography
- Davidsonn, Walter C. & Harley-Davidson Motor Company. "Motorcycles." The New Book of Knowledge. Grolier Inc. ed. 1977.
- Keirin. 1998-1999. Bicycling Popularization Association of Japan. 26 November 2005 <http://www.cycle-info.bpaj.or.jp/english/ride/keirin.html>.
- Monaghan, David W. Bikes: The Wheel Story. 16 November 2005. Canada Science and Technology Museum . 16 November 2005 <http://www.sciencetech.technomuses.ca/english/collection/bikes5.cfm>.
- Neupert, Hannes. "Das Powerbike" The New Book of Knowledge. Moby Dick Verlag, Kiel, 1997, ISBN 3-89595-123-4.
[edit] References
- ^ "China: Exhaustive effort to cut vehicle emissions", China Business Information Network, 10 April 1996. pg. 1, via Financial Times Information Limited.
- ^ a b "China's Cyclists Take Charge", By Peter Fairley. IEEE Spectrum, June 2005
- ^ a b c "Cheap and green, electric bikes are the rage in China", by Tim Johnson. Originally published 23 May 2007 by McClatchy Newspapers.
- ^ "Europe's latest craze electric bikes", Associated Press, 10/14/2008. The article gives China Bicycle Association and Xinhua News Agency's "Economic Reference" newspaper, as the sources of the numbers
- ^ "Horseless Carriages", The Times, 21 May 1896, pg. 6, via The Times Digital Archive
- ^ Public law 107-319 107th Congress
- ^ http://www.erockit.net/
- ^ Technisches "Reglement der Tour de Sol 1989/1990", published by Tour de Sol, Bern, Switzerland
- ^ "BionX website". Retrieved on 2008-10-14.
- ^ 1 Hour of Lawnmower Exhaust = 150 km in Car Exhaust BBC 7jun01
- ^ Cloverdale police department electric scooters
[edit] See also
[edit] External links
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Wikimedia Commons has media related to: Electric bicycles |
- [7]the most comprehensive motored bicycle website
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