An electric bicycle is a bicycle with an electric motor used to power the vehicle, or to assist with pedaling. In many parts of the world, electric bicycles are classified as bicycles rather than motor vehicles, so they are not subject to the same laws as motor vehicles. Electric bicycles are one type of motorized bicycle. However, electric bicycles are defined separately and treated as a specific vehicle type in many areas of legal jurisdiction.
Electric bicycle usage worldwide has experienced rapid growth since 1998. It is estimated that there were roughly 120 million "ebikes" on the road in China as of early 2010.. The “Electric Bikes Worldwide Reports – 2010 Update” estimates that 1,000,000 electric bicycles will be sold in Europe in 2010. The same report estimates that sales in the USA will reach roughly 300,000 in 2010, doubling the number sold in 2009.
In the 1890s, electric bicycles were documented within various U.S. patents. For example, on 31 December 1895 Ogden Bolton Jr. was granted Template:US Patent 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.
Two years later, in 1897, Hosea W. Libbey of Boston invented an electric bicycle (Template:US Patent) that was propelled by a “double electric motor.” The motor was designed within the hub of the crankshaft axle. 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 Template:US Patent by John Schnepf depicted a rear wheel friction “roller-wheel” style drive electric bicycle. Schnepf's invention was later re-examined and expanded in 1969 by G.A. Wood Jr. with his Template:US Patent. Wood’s device used 4 fractional horsepower motors; each rated less than ½ horsepower and connected through a series of gears.
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. 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 80 km/h.
In a parallel hybrid motorized bicycle, such as the aforementioned 1897 invention by Hosea W. Libbey, human and motor inputs are mechanically coupled either in the bottom bracket, the rear or the front wheel, whereas in a (mechanical) series hybrid cycle, the human and motor inputs are coupled through differential gearing. In an (electronic) series hybrid cycle, human power is converted into electricity and is fed directly into the motor and mostly additional electricity is supplied from a battery.
Pedelec is a European term that generally referred to an electric bicycle that incorporated a torque and/or a speed 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 in which 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).
Today, 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; domestic sales reached 10 million in 2005, and 16 to 18 million in 2006. 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. A typical unit requires 8 hours to charge the battery, which provides the range of 25–30 miles (40–50 km), at the speed of around 20 km/h.
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),
Naming and legal statusEdit
Federal law in the United States states that an electric bicycle must have a top speed under 20 mph and a motor which produces less than 750 watts/1 hp. They are not considered motor vehicles by the federal government and are subject to the same consumer safety laws as unassisted bicycles. 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 Template:Convert on motor power alone on level ground. In Alberta the maximum output is 750W, and the max speed is 35 km/h. Age restrictions vary in Canada. All require an approved helmet. Some versions (e.g., if capable of operating without pedaling) 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. 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 pedaling. In some cases regulatory requirements have been complicated by lobbying in respect of the Segway HT.
In the United Kingdom, electric bicycles are classed as standard bicycles and riders do not require a license to use them. However, riders must be of at least 14 years of age and road-legal electric bicycles may not contain a motor with an output power exceeding 250W.
In China, which has the highest number of electric bicycles in the world, electric bikes currently come under the same classification as bicycles and hence don't require a driver's license to operate. Previously it was required that users registered their bike in order to be recovered if stolen, although this has recently been abolished. Due to a recent rise in electric-bicycle-related accidents, caused mostly by inexperienced riders who ride on the wrong side of the road, run red lights, don't use headlights at night etc, the Chinese government plans to change the legal status of illegal bicycles so that vehicles with an unladen weight of 20 kg or more and a top speed of 30kmh or more will require a motorcycle license to operate, while vehicles lighter than 20 kg and slower than 30kmh can be ridden unlicensed. In the southern Chinese cities of Guangzhou, Dongguan and Shenzhen, electric bicycles, like all motorcycles, are banned from certain downtown districts. There are also bans in place in small areas of Shanghai, Hangzhou and Beijing.
Motors and drivetrainsEdit
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 under 750 watts.
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. 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 pedaling. These have a sensor to detect the pedaling speed, the pedaling 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 7 km (uphill on electric power only) to 70 km (minimum assistance) and is highly dependent on whether or not the bike is tested on flat roads or hills. Some manufacturers, such as the Canadian BionX or American E+ (manufactured by Electric Motion Systems), have the option of using regenerative braking, the motor acts as a generator to slow the bike down prior to the brake pads engaging. 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. Some experiments have also been undertaken with super capacitors to supplement or replace batteries for cars and some SUVS.
The energy costs of operating electric bicycles are small, but there can be considerable battery replacement costs. Riding an electric bicycle to work or to the store instead of taking a car has long term financial gains.
Not all electric bicycles take the form of conventional push-bikes with an incorporated motor. Some are designed to take the appearance of low capacity motorcycles, but smaller in size and comprising of an electric motor rather than a petrol engine. Bicycles of note include the Sakura electric bicycle, which incorporates a 200W motor found on standard e-bikes, but also includes plastic cladding, front and rear lights, and a speedometer. It is styled as a modern moped, and is often mistaken for one based on its similarity in appearance.
Other, rarer designs include that of a 'chopper' styled electric bicycle, which are designed as more of a 'fun' or 'novelty' electric bicycle, rather than a purposeful mobility aid or mode of transport.
Various designs (including those mentioned above) are designed to fit inside most area laws, and since they both contain pedals, can be used on roads in the United Kingdom, among other countries.
Most electric bicycles can be locked using keys supplied by the manufacturer. The key is usually inserted into a switch, which is commonly found on the bicycle's handlebars or on one side of the motor compartment. When switched to the "Off" position, the electrical drive system cannot be turned on. In areas of high risk for bicycle theft, these locking mechanisms are used in conjunction with coil or U locks.
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 small size of the battery pack on an electric bicycle, relative to the larger pack used in an electric car, makes ebikes very good candidates for charging via solar power or other renewable energy resources. Sanyo capitalized on this benefit when it set up "solar parking lots," in which ebike riders can charge their vehicles while parked under photovoltaic panels.
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.
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