Introduction
In the modern world, electric and hybrid cars have become a common phenomenon. Numerous people buy such vehicles because they try to reduce the amount of carbon emission, which is useful for the environment. Current technology aims at increasing the energy capacity of these cars to allow drivers to overcome longer distances without charging, and Regenerative Braking Systems (RBS) are a suitable option here.
It is so because this model makes it possible for a hybrid or electric car to obtain a portion of energy while braking. In general, when a vehicle applies brakes, it produces kinetic energy that can be turned into fuel for such cars with the help of a specific structure. This technology is requested now because it contributes to the longer working cycles of the vehicles. However, the RBS is not an ideal technology, and it implies some concerns. Thus, the main objectives of this research are to present a schematic of this model, explains how it works, comment on its advantages and disadvantages as well as predict its future.
Schematic
In general, the RBS is a relatively simple circuit that implies two modes. On the one hand, it is necessary to comment on a drive mode. Since the system under consideration refers to pure electric and hybrid cars, it is not a surprise that a battery is a central part of this system. This device stores energy and a motor consumes it to affect the transmission and make the wheels turn. This process is the main aspect that makes such vehicles move.
On the other hand, a regeneration mode implies an appropriate component that refers to a motor controller that predetermines how a car will apply brakes. It is so because this device has the potential to generate some energy by making the motor work differently. Once this happens, the electric current appears, and the motor controller transforms it back to the battery. Consequently, one can say that the RBS is a closed circuit, where the dual nature of the motor contributes to the fact that it both uses and generates energy. Figure 1 below by CarBike Tech (2019) demonstrates the energy flow and the correlation between the system components.
One should mention that the system above describes the performance of pure electric cars. When it comes to hybrid vehicles, however, it is not necessary to forget that such cars have both electric motors and mechanical transmission. Thus, Gupta, Khan, and Khan (2019) stipulate that these systems manage to work together with the help of power-split devices that make it possible to choose an appropriate source of energy to power a vehicle. Thus, such cars have two various sources of power, but it does not offer any issues for regenerative braking. When an RBS is applied, it sends obtained energy back to the batteries, rather than to the engine.
Working Principles
Even though the RBS seems to be a complicated technology, it works with the help of principles that are easy to understand. According to Gupta, Khan, and Khan (2019, p. 1600), a regenerative brake “is a mechanism that reduces vehicle speed by converting some of its kinetic energy into another useful form of energy – electric current.” This transformation is possible because a motor acts as a generator.
Usually, a motor turns the wheels in an appropriate direction to make a vehicle move, which results in the creation of kinetic energy. When conventional braking systems are applied, they affect the wheels to make a car stop, and the kinetic energy disappears as heat.
When it comes to electric and hybrid cars, however, there is a possibility to reuse this resource and avoid heat emission. Here, when a driver brakes, it initiates a reverse rotation of the motor, which reduces the speed without friction. One should mention that there is friction neither between the wheels and the brakes nor between the wheels and the ground. In this case, the kinetic energy does not vanish but affects the motor to generate an electric current. After that, the produced power flows to a battery where it is stored for future use (Karthik, 2019, para. 6).
Effective work of the RBS is possible mainly because of motor controllers. It is so because these devices analyze the speed of wheel rotation, decide when braking begins and stops as well as control the inflow of electricity in vehicle batteries. Here, it is necessary to mention that batteries have limited capacity, which means that generating power can be harmful to a vehicle under certain conditions. If such a situation occurs, and a driver presses the brake pedal to stop, the motor controller chooses to use a conventional braking system instead of an RBS to reduce the vehicle speed.
RBS Advantages and Disadvantages
As has been mentioned above, the RBS has both positive and negative features. It is a normal phenomenon because it is impossible to invent technology that would not have any drawbacks. Thus, mentioning these features is necessary to identify the merits and flaws of this system, which will demonstrate whether it is beneficial to use the RBS in the modern world. In addition to that, the adverse elements can show what improvements the given technology requires.
Disadvantages
To begin with, many people mention that the RBS is not worth considering because it cannot restore all energy that has disappeared or even close to it. According to Loveday (2019, para. 5), regenerative braking can only restore up to 30% of initial energy. That is why it is impossible to say that this system provides vehicles with essential fuel intake. Furthermore, there exists a belief that the brakes of this kind are not effective when high speed is involved, which endangers electric and hybrid car drivers and other road users (Zhang, 2018). As a result, such vehicles are also equipped with conventional friction brakes to meet safety requirements.
The next disadvantage relates to the construction of the given systems. As a rule, electric and hybrid cars have ordinary batteries as their source of energy. Even though they are popular now, it does not mean that these devices are free from defects. Partridge and Abouelamaimen (2019, p. 1) stipulate that high power charging can cause battery “degradation, impacting performance and lifetime.” The researchers emphasize that it is more reasonable to use supercapacitors because they can absorb much power and possess excellent cycling features (Partridge and Abouelamaimen, 2019).
In addition to that, one should recall that the presence of the RBS does not eliminate the necessity to equip cars with conventional braking systems. According to Loveday (2019, para. 7), friction brakes are mainly required to bring a vehicle to a full stop. The disadvantages above show that this technology can offer some problems, but its positive phenomena that will be presented further mitigate the adverse impact.
Advantages
Even though the RBS can only restore a small part of the energy used, fuel economy is the most significant benefit when it comes to using such braking systems. It is so because this invention can provide vehicle batteries with regular intake of power irrespective of its amount. It is so because even insignificant portions of energy increase the working cycles of vehicles. Consequently, drivers can charge their cars without the necessity to stop and find appropriate stations. This option results in cheaper and more convenient maintenance of the vehicles, which is attractive for multiple individuals.
In addition to that, the absence of friction that has been explained above denotes that the vehicle braking system and tires feature longer working lives. There is no doubt that this fact contributes to the more effective performance of such cars. Furthermore, since any friction is absent, electric and hybrid vehicles apply brakes without producing heat and dust that harm the environment.
The information above demonstrates that the RBS has essential benefits that explain why the given system is applied in the modern world. This system is suitable for electric and hybrid cars, but its drawbacks show that the RBS application implies a few concerns. At the same time, engineers try to overcome the adverse effects with the help of the advantages that are present in the fields of fuel efficiency, costs, performance, and environmental impact.
Alternative Use and the Future of Technology
Even though it has been mentioned a few times that the RBS is suitable for electric and hybrid cars, these vehicles are not the only area of application of this system. Gupta, Khan, and Khan (2019) explain that the RBS is also applied in railway transportation, where electricity generated during braking is sent back to the supply chain. The researchers stipulate that the railway industry witnesses a more effective use of this braking system because it can return up to 40% of initial energy (Gupta, Khan and Khan, 2019, p. 1606).
Consequently, one can say that it is possible to increase RBS efficiency. In addition to that, the given system is useful in so-called real-life conditions. It refers to the fact that individuals can use the RBS principles to generate electricity at home. In this case, a bicycle generator is a suitable example that demonstrates how people can benefit from the alternative use of regenerative braking.
The future of this technology depends on whether engineers will manage to minimize its disadvantages and strengthen its positive features. Here, the most significant attention should be drawn to increasing the energy return rate and using a useful source of power. While achieving higher energy restoring rates seems to be a hypothetical goal, there exist firm hopes that it is possible to improve the situation with specific power elements. As has been mentioned, traditional batteries are not effective because they tend to degrade because of high power charging.
At the same time, they can be profitably replaced by supercapacitors that are known as productive electrochemical devices. Partridge and Abouelamaimen (2019, p. 2) stipulate that the supercapacitors feature “rapid charge/discharge cycle, long cycle life and very high power densities.” That is why it could be logical to suppose that the use of these devices would increase the efficiency of regenerative braking. However, the difference is not essential because of lower charge rates at the end of the charging profile, which is explained by the structure of supercapacitors (Partridge and Abouelamaimen, 2019). As a result, these devices have the potential to make the RBS future better, but it requires more engineering effort.
Conclusion
Regenerative braking systems can be applied in a few spheres, but electric and hybrid cars stand for the most popular variant. When evaluating the performance and effectiveness of these systems, it is necessary to determine what consequences they are expected to generate at first. On the one hand, when some people consider regenerative braking an almost limitless source of energy for electric vehicles, the systems fail to cope with the task because they have limited capacity. On the other hand, regenerative braking becomes more efficient when it appears as an auxiliary power source that can increase the working cycles of specific vehicles. This information denotes that the effectiveness of this technology is a variable that depends on who evaluates this phenomenon.
However, it is possible to compare regenerative braking with conventional braking systems to determine which one is more effective. Thus, traditional braking is better because it can bring a car to a standstill, and this system is irreplaceable for emergency stops. When it comes to other parameters, regenerative braking systems apply essential advantages. Firstly, they do not waste kinetic energy because it is transformed into additional power for electric cars.
It is of significance in the modern world, where recycling trends are popular. Secondly, the absence of friction leads to longer working cycles of tires and braking systems, which leads to both economic and performance benefits. Finally, regenerative braking does not have any negative influence on the environment and saves the existing resources. Thus, one can say that regenerative braking systems are useful devices, but their positive impact can become better with the help of further innovation.
Reference List
CarBike Tech (2019) What is regenerative braking in cars and how does it work? Web.
Gupta, R., Khan, N. and Khan, S. (2019) ‘Comparative study on regenerative braking system,’ International Research Journal of Engineering and Technology, 06(07), pp. 1599-1606.
Karthik, S. H. (2019) How regenerative braking works in electric cars. Web.
Loveday, E. (2019) What is regenerative braking and why is it useful for electric cars? Web.
Partridge, J. and Abouelamaimen, D. I. (2019) ‘The role of supercapacitors in regenerative braking systems,’ Energies, 12(14), pp. 1-15.
Zhang, H. (2018) ‘Research on regenerative braking combined control method for ESP of pure electric cars,’ Chemical Engineering Transaction, 66, pp. 1315-1320.