Regenerative Braking Mechanism Research Articles

POWERING THE EV WITH DYNAMOS

The dynamo, traditionally used in bicycles to convert mechanical energy into electrical energy, can be adapted for use in EVs to supplement battery power. As the vehicle moves, the dynamo harnesses kinetic energy, converting it into electricity to recharge the EV's battery. This regenerative braking mechanism not only extends the vehicle's range but also reduces reliance on charging stations, enhancing the EV's practicality and autonomy. The integration of a dynamo system introduces a sustainable element by utilizing kinetic energy that would otherwise be dissipated as heat during braking. By capturing and converting this energy, EVs equipped with dynamos can operate more efficiently, reducing overall energy consumption and carbon emissions. This abstract explores the technical feasibility, potential benefits, and challenges associated with implementing a dynamo system in EVs. Considerations such as optimal placement, efficiency optimization, and compatibility with existing battery and electrical systems are discussed. Additionally, the economic viability and environmental impact of widespread adoption of dynamo-equipped EVs are evaluated. The integrating dynamos into EVs presents a promising avenue to address range anxiety and charging infrastructure limitations, while also promoting sustainability and energy efficiency in the transportation sector. Further research and development are warranted to optimize the design and implementation of this innovative solution for powering electric vehicles.

Electric truck gravity energy storage: An alternative to seasonal energy storage

AbstractThe global shift toward a sustainable and eco‐friendly energy landscape necessitates the adoption of long‐term, high‐capacity energy storage solutions. This research introduces an inventive energy storage concept involving the movement of granular materials from a lower elevation to a higher point within natural terrains such as mountains or excavated mining sites. Electrical energy is employed to charge electric batteries that elevate the granular material, thereby storing potential energy. Subsequently, this material is transported down during the electricity generation phase, and the regenerative braking mechanism converts the gravitational energy to replenish the vehicle's battery. The stored energy within these vehicles is then dispatched during peak demand periods or utilized by the vehicles for other freight transportation purposes. Our findings demonstrate a power cost of 1200 USD/kW, an energy storage expense spanning from 1 to 10 USD/kWh, a levelized cost of storage ranging from 35 to 200 USD/MWh, and a global annual potential of approximately 5.4 PWh. Electric vehicle gravity energy storage showcases its capability to bolster sustainable development by offering seasonal and multi‐year energy storage services.

State of the art on challenges for friction material manufacturers – raw materials, regulations, environmental, and NVH aspects

Friction materials have played a crucial role in safe movement of automobiles and in protection of human life. Enormous cost has incurred in validation of new developed brake pad, a critical safety component, as it involves a lot of inhouse testing along with field testing in different terrains. Further, with an unexpected pandemic and wars, creeping raw material price increases which is a major issue even though researchers have tried to develop innovative materials, which can perform multitasks. Moreover, a paradigm shift towards hybrid and electric vehicles required adjustments in design strategies, related to new friction materials for brakes. The regenerative braking mechanism has taken a major role in electric vehicles (EVs). Therefore, the friction pad is rarely used, which leads to rust/corrosion issues. In addition, the exhaust particles now pale in comparison to non-exhaust emissions. It is a newly identified challenge faced by friction industry as the brake pad wear is one of main contributors of non-exhaust emissions. Also, with no engine noise to cover, the silent nature of EVs creates noise and vibration issues in brake pad even more apparent. Hence, this paper has focused critically on challenges for friction material manufacturers in terms of regulations and raw materials followed by environmental issues and shift towards EVs and NVH requirement. Further, it has discussed with some possible suggestions to reduce the same.

The Integrated Kinetic Energy Recoup Drive (i-KERD): An Optimized Powertrain for EVs, HEVs and FCEVs

In this paper, a particular form of flywheel hybrid powertrain, namely, the Integrated Kinetic Energy Recoup Drive (i-KERD) is fully explored and its applications for EVs, HEVs and FCEVs in recent years to show the energy-savings and performance enhancement potential of this innovative powertrain technology. It is shown that the i-KERD is a small highspeed flywheel integrated into an e-CVT, or power-split hybrid drive. Under NEDC or WLTC, typically it can achieve some 40% energy savings and >50% gain in 0–100 kph acceleration due to effective regenerative braking mechanism of the integrated flywheel power system. In addition to its “peak-shaving” capability, the highly-efficient, long-life flywheel power on-board, is able to keep the kinetic energy of the vehicle fully recycled, rather than dissipated during braking. The i-KERD technology has also been applied to urban railway transportation (i.e., underground railway) and off-road heavy construction equipment, where regenerative braking plays a great role on energy efficiency.

A Semi-recumbent Eccentric Cycle Ergometer Instrumented to Isolate Lower Limb Muscle Contractions to the Appropriate Phase of the Pedal Cycle.

Eccentric (ECC) cycling is used in rehabilitation and sports conditioning settings. We present the construction and mode of operation of a custom-built semi-recumbent ECC cycle designed to limit the production of lower limb muscle activity to the phase of the pedal cycle known to produce ECC contractions. A commercially available semi-recumbent frame and seat (Monarch, 837E Semi-recumbent Bike, Sweden) were used to assemble the ergometer. An electrical drive train system was constructed using individual direct drive servo motors. To avoid active muscle activation occurring during the non-ECC pedaling phase of cycling, a “trip” mechanism was integrated into the drivetrain system using a servo-driven regenerative braking mechanism based on the monitoring of the voltage produced over and above a predetermined threshold produced by the motors. The servo drive internal (DC bus) voltage is recorded and internally monitored during opposing (OPP) and non-opposing (N-OPP) phases of the pedal cycle. To demonstrate that the cycle functions as desired and stops or “trips” when it is supposed to, we present average (of 5 trials) muscle activation patterns of the principal lower limb muscles for regular ECC pedal cycles in comparison with one pedal cycle during which the muscles activated outside the desired phase of the cycle for a sample participant. This semi-recumbent ECC cycle ergometer has the capacity to limit the occurrence of muscle contraction only to the ECC phase of cycling. It can be used to target that mode of muscle contraction more precisely in rehabilitation or training studies.

Increasing the Cruise Range and Reducing the Capital Cost of Electric Vehicles by Integrating Auxiliary Unit with the Traction Drive

Poor cruise performance of Electric Vehicles (EVs) continues to be the primary reason that impends their market penetration. Adding more battery to extend the cruise range is not a viable solution as it increases the structural weight and capital cost of the EV. Simulations identified that a vehicle spends on average 15% of its total time in braking, signifying an immense potential of the utilization of regenerative braking mechanism. Based on the analysis, a 3 kW auxiliary electrical unit coupled with the traction drive during braking events increases the recoverable energy by 8.4%. In addition, the simulation revealed that, on average, the energy drawn from the battery is reduced by 3.2% when traction drive is integrated with the air-conditioning compressor (an auxiliary electrical load). A practical design solution of the integrated unit is also included in the paper. Based on the findings, it is evident that the integration of an auxiliary unit with the traction drive results in enhancing the energy capturing capacity of the regenerative braking mechanism and decreases the power consumed from the battery. Further, the integrated unit boosts other advantages such as reduced material cost, improved reliability, and a compact and lightweight design.

Carbon nanotube torsional springs for regenerative braking systems

The modeling and demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as energy-storing actuators for regenerative braking systems. An originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing incrementally until failure. The measured average extractable energy density values are 2.9 kJ kg−1 ± 1.2 kJ kg−1 and 3.4 kJ kg−1 ± 0.4 kJ kg−1 for 1-ply CNT yarns and 2-ply CNT yarns, respectively. Additionally, a regenerative braking system is demonstrated to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yarn’s twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking setup are on average 3.3 kJ kg−1 and 0.67 kW kg−1, respectively, with maximum measured values of up to 4.7 kJ kg−1 and 1.2 kW kg−1, respectively. A slightly lower energy density of up to 1.2 kJ kg−1 and a 0.29 kW kg−1 mean power density are measured for CNT yarns in a more complex setup that mimics a unidirectional rotating regenerative braking mechanism.

Embedded Control Scheme of Stand-Alone Regenerative Braking System using Supercapacitors

The concept of Energy Storage System (ESS) in Electric Vehicle (EV) is the most important challenging part of EV design. Batteries are the main electric ESS which has mostly used for supplying the energy requests and charging the Batteries is a major concern. Supercapacitors based on their specifications are effective for this role. Very high power delivery and fast charging are the most famous parameters of supercapacitors which make them suitable for EVs. This paper describes a novel scheme to manage multiple supercapacitor banks which will assist in continuous storing of braking energy and expend on to the load once fully charged. In the present design, the system monitors the State-Of-Charge (SOC) of each supercapacitor in the bank during each charge/discharge sequence for efficient utilization of produced energy via braking. Supercapacitor bank is designed by connecting the supercapacitor cells in series to increase the rated voltage. Nevertheless, each supercapacitor bank may suffer from the unstable charging consequence due to its inherent characteristic between each supercapacitor in the bank even though all these supercapacitors having the same specification. It is imperative to design a balancing circuit to evenly distribute the stored energy failing which the imbalance will cause some supercapacitors in the bank to reach the overcharging state. The present design prevents the supercapacitor bank from unwanted overcharging and helps protecting other supercapacitors in the bank itself. In this paper, we present a new control scheme which controls and monitors charge/discharge mechanism of supercapacitor bank with a view to incorporate the balancing circuit design for regenerative braking mechanism developed as part of the work.

Regenerative braking systems with torsional springs made of carbon nanotube yarn

The demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as an energy-storing actuator for regenerative braking systems. Originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing until failure. The maximum extractable energy density is measured to be as high as 6.13 kJ/kg. The tests also reveal structural reorganization and hysteresis in the torsional loading curves. A regenerative braking system is built to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yam's twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking system are up to 4.69 kJ/kg and 1.21 kW/kg, respectively. A slightly lower energy density of up to 1.23 kJ/kg and a 0.29 kW/kg mean power density are measured for the CNT yarns in a more complex system that mimics a unidirectional rotating regenerative braking mechanism. The lower energy densities for CNT yarns in the regenerative braking systems as compared with the yarns themselves reflect the frictional losses of the regenerative systems.