Motorized bicycle
From Wikipedia, the free encyclopedia
A motorized bicycle is a bicycle with an attached motor used to assist with pedalling. 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
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- 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 1862 by Pierre Lallement from France. By 1888 John Dunlop invented pneumatic tires and the chain drive making possible the safety bicycle, where the two wheels had the same diameter.
[edit] Electric bicycle history
Shortly afterwards, 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 where 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 was 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.
The late 1990s to early 2008 demonstrated a resurgence in electric bicycles. 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.
By 2001 the terms, E-Bikes, pedelec, assisted bicycle and power-assisted bicycle where commonly used to describe electric bicycles. E-bike, a term that has decreased in trend, generally referred to an electric bicycle which used a throttle. Pedelec is a European term that generally referred to an electric bicycle that incorporates a torque sensor and/or power controller that delivered a proportionate level of assist and only ran when the rider pedaled. 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.
[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 to the bicycle form.[2]
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.
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 drive 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 internal combustion (IC) engine. Electric bicycles are gaining acceptance, especially in Europe and Asia, in response to increasing traffic congestion, an ageing 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 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 & 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).
While generally not known[citation needed] 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 power under 750 watts) are not considered motor vehicles by the federal government and are subject to the same consumer safety laws as unassisted bicycles[3]. 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 peddling) 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, but most current models use electric motors. A few still use small two stroke or four stroke IC engines, most notably the Derny still used for pacing of bicycle races.
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 or behind the rider may drive the rear wheel with a chain or rubber belt (e.g. Derny)
- 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.Zeta)
- 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 some rediscovered kits.
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.
[edit] Electric
There are many possible types of electric motorized bicycles with several technologies available for electric motors, 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. Chain drive and hub motors are both common, friction drive less so. Most hub motors are in the 250w to 450w category, however there are some available with up to 2000 watts such as Crystalyte Phoenix.
Electric bicycles are generally powered by rechargeable batteries. These are normally charged from the utility supply (mains), with perhaps the option of using the motor to effect regenerative braking or charging while being pedalled or rolling downhill. There are also experiments with recharging via solar panels and, to a lesser extent, other alternative energy sources such as fuel cells. Most modern electric bikes use technologies such as rare earth magnets, pulse width modulated power electronic control and regenerative braking to improve efficiency. Batteries are usually either lead-acid, NiCd, NiMH or Li-ion. Lithium ion polymer batteries are now beginning to be used as well, offering the advantage of lighter weight for the same energy storage capability but at a higher cost.
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), where the electric motor is regulated by pedalling. These may have a mechanism such as a crank sensor to detect when the user is pedalling, or a more sophisticated torque sensor. The degree of assistance can usually be controlled to optimise battery life.
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 combined. The range of an electric bike is usually stated as somewhere between 7km (uphill on electric power only) to 70km (minimum assistance).
[edit] Other power sources
- For history of steam cycles, see steam tricycle
Individuals have built bicycles powered by steam and air engines, and there is at least one example of a jet propelled bicycle. No large-scale manufacture of any of these is known.
Some experiments have also been undertaken with supercapacitors to supplement or replace batteries.
[edit] Environmental effects
The environmental effects of motorized bicycles varies according to the power source.
Two stroke engines, common in those powered by internal combustion engines, often emit more pollution than automobiles due to partial combustion of the upper cylinder lubricant necessarily included in the fuel. One Swedish study found that running a 2-stroke lawnmower for half an hour pollutes as much as a 150 km trip in an average car.[4]
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.
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 [7] or Cloverdale, California police with Zap electric bicycles.[5]
[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>.
[edit] References
- ^ "China: Exhaustive effort to cut vehicle emissions", China Business Information Network, 10 April 1996. pg. 1, via Financial Times Information Limited.
- ^ "Horseless Carriages", The Times, 21 May 1896, pg. 6, via The Times Digital Archive
- ^ Public law 107-319 107th Congress
- ^ 1 Hour of Lawnmower Exhaust = 150 km in Car Exhaust BBC 7jun01
- ^ Microsoft Word - programs.doc
[edit] See also
- Electric motorcycles and scooters
- Electric vehicle conversion
- Low Speed Vehicle
- Timeline of transportation technology
[edit] External links
- UK's National Autocycle and Cyclemotor Club (NACC)
- Croydon Cycling Campaign - Electric-Assist Cycles page describes pros and cons, and provides details and references for status under UK and European Union law.
- The 175 Watt Solution. An EVWorld.com article from October, 2006 describing different styles of electric bicycles available in the USA.
- Electric Buyers' Guide A Buyers' Guide Compiled by 'A to B' magazine. Nov. 2006
- Series Hybrid Cycle Chainless Human Powered Vehicle with pedalled Generator
