Electric Bicycles (e-Bikes), Next-Generation Low Carbon Transport Systems

 

Electrically assisted bicycles (e-Bikes) represent an emerging sustainable mode of transport for future smart cities. Several design issues impact policy in several countries such as the UK, Europe and the USA. As Electrically assisted bicycle e-bike usage continues to grow, so too will the need for further research, in order to provide the necessary data to inform industrialists what cycling features matter for a wider, diverse, and sustainable adoption of this mode of transport. This investigation discusses results from a survey on end-user preferences for future electrically assisted bicycles e-Bikes that will be developed in the coming years. User preferences related to safety and convenience were defined using market reviews and responses gathered from 638 potential users mainly from Europe and North America. Data were analyzed to rank the importance of desired functionality to improve the uptake of cycling within urban environments. In general, the results indicate that safety and convenience features were equally valued across the whole sample size. ‘Gradient Climb Assist’ and ‘Break Lights & Indicators’ were respectively the most preferred convenience and safety features. This survey showed how respondents expressed a desire for more intelligent, secure, and adaptive electrically assisted bicycles e-Bikes.

 

Benefits of Electrically assisted bicycles (E-bikes)

 

• Electrically assisted bicycles (E-bikes) charring station sign

Riding an e-bike is a lot like riding a regular bike with the added boost of an electric motor. And having this motor with pedal assist has some advantages. Let's take a look at a few.

 

• Improved physical health

Some people may think because the bike is electric and takes less effort to ride that it's not really exercised. A study conducted out of Brigham Young University and published in the Journal of Medical Internet Research found that people who ride electric bikes experience nearly as much exercise as those who ride mountain bikes without feeling as if they've had a difficult workout. The truth is that even with pedal assist, riders still have to pedal which results in burning calories. It's a great cardiovascular exercise that can help build endurance and muscle.

 

• Easier to ride

 

Pedal-assist gives riders a boost. It helps with hills, inclines, and rough terrain, allowing for a smoother ride thus reducing stress on joints. You can also ride with greater power and precision than a regular bike. And it gets people cycling who may not otherwise ride a traditional bike because of physical aches and pains. Additionally, you can take longer rides without physical exhaustion.

 

• Better mental health

 

E-bikes make cycling more accessible and people are more likely to do it because it's easier, getting about the same workout with less effort. For those who may be living an otherwise sedentary life, riding an e-bike gets them moving and in nature. This exercise, change in scenery, and fresh air helps improve mood, reduce stress, provide for a more restful sleep, and increases productivity.

 

• A great alternative to cars

 

E-bikes are great for commuting to work a few miles away and for running quick errands. Because it's classified as a bike, in many cities, you can ride on sidewalks and in bike lanes, and cut across parks. With alternative ways to travel to your destination, your commute can be faster than a car stuck in traffic. When people ride their e-bikes instead of driving, they cut down on gas and pollution, helping to improve air quality and the environment.

 

• Faster and safe

 

Most cyclists travel 10 to 12mph, but an e-bike can average 20mph. E-bikes allow you to get to your destination faster than a regular bike. E-bikes are not more dangerous than regular bikes. They just have different risks. E-bikes tend to be safer than regular bikes because you can accelerate to get out of the way faster and travel at higher speeds, keeping up with traffic.

Now that you've learned the benefits of e-bikes, you'll want to consider protecting your e-bike with insurance. Your e-bike is an investment and you want to make sure you have adequate coverage for theft or damage. It's a risky move for your e-bike to be uninsured. Fortunately, there's bicycle insurance specifically for e-bikes. Electric bike insurance provides coverage between auto, home, and renters insurances where there are gaps and fine print exclusions.

Markel Specialty can offer a stand-alone electric bike insurance policy that insures e-bikes with power assist up to 750 watts and covers theft, damage, and more. Policies start as low as $100 per year and offer a variety of coverage levels and deductible options.

Each policy can be customized to fit you and your riding style. Coverages can include protection for damage caused by theft, crash, collision, fire, attempted theft, vandalism, or hitting another object. Coverage of spare parts, cycle apparel, and rental reimbursement can also be included at no additional cost.

A modern peddle

Currently, commercially available, peddles dominate the European and North American markets. Although their design varies depending on manufacturers it is possible to identify basic components that each peddle shares.

Fig. 1, below, offers an overview of the main components of a modern peddle: (i) an electric motor, which can have various positions and technology; (ii) a motor controller, fit with torque sensors and cadence sensors to respond to the cyclist’s inputs; (iii) a battery pack; (iv) a user interface system; and (v) a speed sensor.

 

Battery pack

There are several types of electrically assisted bicycles (E-bikes) batteries on the market, including lead-acid, nickel-metal hydride (NiMH), and, lithium-ion (Li-ion) (Weinert et al., 2007).

Li-ion batteries are roughly twenty times more expensive per unit of energy than a lead-acid battery than and twice as expensive as a NiMH battery. It is estimated that lead-acid batteries cost about $35/kWh while NiMH about $350/kWh and Li-ion up to $710/kWh (Curtis, 2014, Hung and Lim, 2020). Prices of Li-ion batteries built by Tesla Motors and Panasonic cost around $300 per kWh, with the target of reducing the price to $100/kWh by improving product design and production techniques (Holland, 2018). Currently, 70% of the cost of producing these batteries comes from the raw materials needed (Fogel, 2016).

The mass of a Li-ion battery is circa ¼ compared with a lead-acid battery of the same capacity (Hung and Lim, 2020), this has allowed manufacturers to create electric bicycles weighing below 20 kg (Salmeron-Manzano and Manzano-Agugliaro, 2018). Currently, a lithium battery pack accounts for 30% of the e-Bike mass (e.g., ranging from 2.0 to 3.5 kg (Robert Bosch GmbH, 2021)) and 48% of its cost (Kerdsup and Fuengwarodsakul, 2017). The mass of the battery influences its installation location and the subsequent comfort of the ride (Hung and Lim, 2020). For example, batteries installed under the seat tube have proved to provide better ride comfort than batteries fitted in the rear cargo rack, based on the analysis of the weighted vertical acceleration (W-Acceleration) on the saddle (Du et al., 2009).

 

Electric motor

 

Currently, most e-Bikes use a Brushless Direct Current (BLDC) motor due to its compact size and high efficiency in comparison with brushed motors (Chlebosz et al., 2010). However, BLDC motors result be more expensive (e.g. typically twice as much as a brushed DC motor with the same power rating) as they require costly permanent magnets for field excitation (Chlebosz et al., 2010).

 

The main options with respect to the mounting location of the motor in an e-Bike include: (i) the front hub, (ii) the rear hub, (iii) the middle of the bike frame also known as mid-drive, and (iv) over the rear wheel in the friction drive as shown above in Fig. 2.

 

Fig. 2. Motor positioning. (i) Rear Hub; (ii) Friction Drive; (iii) Mid-Drive; (iv) Front Hub.

Each position provides advantages and disadvantages with respect to e-Bike performance. Most current e-Bike motors are mounted on either the front or the rear wheel hub (Muetze and Tan, 2007). A rear hub motor position provides benefits including improved ride quality, direct motor-to-wheel power transmission, and allowance for a compact frame design.

Motor controller and sensors

Modern peddles in Europe operate largely with a motor controller using a “constant gain” strategy. This logic is simple and based on three main factors: (i) torque input from the cyclist, (ii) cadence used, and (iii) speed of the vehicle.

The user is asked to select a level of assistance (or a gain) from a set of 3 to 5 modes, depending on the manufacturer and the model of the e-Bike. In normal operation, the controller measures the torque that the cyclist inputs at each pedal crank revolution and controls the Direct Current (DC) motor to generate a torque controlled by the gain selected. The typical gain value ranges from 70% to 300% of human input.

To comply with EU regulations, the vehicle is limited in speed, therefore once the speed limit is reached (25 km/h in the EU) the motor controller disables any assistance.

Furthermore, most of the DC motors used, operate with gearing to guarantee torque performances, spinning at speeds often tens of times higher than the cyclist cadence. This results in issues at higher cadence where it is common to see e-Bikes not able to deliver the power quickly enough.

 

Smart sensors and intelligent features

Although the electric bicycle market is becoming established globally, electrically assisted bicycles (E-bikes) with embedded intelligence are very much in their infancy (Smart e-bikes research project, 2018).

Various e-Bike brands' offerings include features marked as “intelligent” purely for marketing reasons. Built-in onboard computer systems with internal Global Positioning System (GPS), anti-theft tracking systems, and connectivity options to smartphones via Universal Serial Bus (USB) and Bluetooth (Yamaha Motor Co., Ltd., 2017, Robert Bosch GmbH, 2021, Shimano, 2017, Panasonic Industry Europe GmbH, 2018, Brose Antriebstechnik GmbH & Co., 2017). Other e-Bikes enable users to plug in their smartphones and use their GPS and built-in sensors' apps to analyze and display information to the rider or to share data on social networks (Robert Bosch GmbH, 2021). Typical functionality includes navigation, performance logging, and health monitoring. More recently, interactive feedback on the handlebars, using flashing lights and vibration are available in the crowdsourced Electrically assisted bicycles (E-bikes) by Canadian company Vanhawks Valour to help the cyclist follow routes with minimal distractions from the road ahead and associated hazards (Anon, 2014).

In addition, currently, purported intelligent Electrically assisted bicycles (E-bikes)provide users with data e.g. bike’s location (i.e. longitude, latitude, altitude, and time), usage (i.e. use of the motor assistance), and other sensor data (e.g. seating pressure, foot pressure location) without offering reasons as to why these data can be useful to a user group (Kiefer and Behrendt, 2016).