**1. Introduction**

Currently, the world is facing environmental degradation and an energy crisis as carbon emissions increase rapidly. A dramatic shift from internal combustion engine vehicles (ICEVs) to electric vehicles (EVs) can be observed in the automotive sector. Because petroleum is the principal fuel utilized in ICE vehicles, which are a significant contributor to the overall environmental catastrophe, EVs are the perfect alternatives [1,2]. An EV is one that runs on electricity rather than an internal combustion engine, which produces energy by consuming a mixture of oil and gases. As a result, EVs are seen as a potential alternative to current-generation cars to counter increasing pollution, environmental degradation, natural resource depletion, etc. [3]. Although there has been a very long period of the notion of electric vehicles, they have attracted significant interest in the last decade in the face of increasing carbon emissions and the other repercussions of fuel vehicles in the ecosystem.

As environmental issues continuously increase, governments across the globe have implemented numerous carbon dioxide and nitrogen oxide emission limits. From those

**Citation:** Alosaimi, W.; Ansari, M.T.J.; Alharbi, A.; Alyami, H.; Ali, S.; Agrawal, A.; Khan, R.A. Toward a Unified Model Approach for Evaluating Different Electric Vehicles. *Energies* **2021**, *14*, 6120. https:// doi.org/10.3390/en14196120

Academic Editors: Guzek Marek, Rafał Jurecki and Wojciech Wach

Received: 9 September 2021 Accepted: 23 September 2021 Published: 26 September 2021

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perspectives, EVs, primarily based on electricity, would be able to soon replace traditional internal combustion engine vehicles, utilizing state-of-the-art electronic power systems, engine motors, electricity-generation systems, production of sustainable energy, as well as smart grids. EVs may be split into hybrid EVs (HEVs), plug-in HEVs (PHEVs), and EVs, based on the current design of the power generation and the system content. Industrialized nations have aggressively established numerous economic considerations in recent times in order to further support electrical engineering firms and research initiatives. Indeed, in the past 10 years, the power electronics industry and its infrastructure have grown rapidly [4,5]. Vehicles generate much carbon pollution that enters our natural surroundings, exposing us to pollution and global warming. An electric vehicle is a big step towards improving the quality of the environment effectively. EVs receive their energy from their rechargeable batteries. These batteries not only control the vehicles, but they are also utilized to power the lights and wipers. The batteries of electric automobiles have higher fuel economy and have lower fuel costs than a conventional petrol car. It is the same kind of battery that is commonly required when a gasoline engine is running. The advantages of electric vehicles are clear. With the development of new technology that promises to decrease the charging durations in minutes, increase the range, and achieve efficient security and technology, there has never been a greater moment to move to an EV. Figure 1 shows the several benefits of using EVs.

**Figure 1.** Several benefits of electric vehicles.

Consumers anticipate additional technological advancements and the introduction of new variants. Consumer behavior in the electric vehicle market is shifting from early buyers and technophile buyers to widespread adoption. Substantial advancements in technology, as well as a greater range of electric vehicle models on the market, have influenced consumer purchasing preferences. Automobiles will remain as a primary factor in energy requirements. China, India, and the Middle East are increasingly placing so many new automobiles on the road that the usage of oil for transportation fuel will continue to expand, and by 2035, it will require 12% more barrels compared to 2016. However, after 2025, there will still be a serious challenge for electric vehicles. Market shares are expanding tremendously above forecasts, with battery advancements boosting quicker than anticipated. In the present basic case, we perceive that the accumulation of EVs will be

almost 100 million by 2035, with a daily fuel demand of approximately one to two million barrels per day. Figure 2 shows the intense growth in the electric vehicle market as per the report [6] published by Wood Meckenzie.

The emergence of the EV industry triggered a global economic transformation. Therefore, evaluation of different EVs' effectiveness is a significant and challenging task. There seems to be no ideal strategy for EV evaluation. Even a well-planned evaluation method may encounter difficulties. To meet this objective, multicriteria decision-making (MCDM) approaches are used in conjunction with the fuzzy set concept to establish a unified model for the effectiveness assessment of different EVs, given that each EV can have its own set of mechanisms and quality to evaluate. Furthermore, a lack of resource availability causes decision makers to make judgments under high ambiguity, resulting in unanticipated outcomes. As a result, dealing with ambiguous and contradictory information necessitates the use of a fuzzy-based unified model for collecting and organizing technical and analytical data. In this paper, we used a fuzzy-based unified model approach for evaluating the effectiveness of different EVs.

This research work is presented in different sections. Section 2 deliberates several similar existing pieces of literature. An overview of the different types of electric vehicles is discussed in Section 3, and Section 4 presents the method and results of this study. Section 5 recapitulates and concludes the research work.

#### **2. Related Works**

Wang et al. [7] presented an assessment of trust for the heterogeneous network of vehicles in sustainable development with electric vehicles. The benefits of low energy usage and high assessment precision were derived from the transport trust assessment compared to the standard trust evaluation process. Hashemnia and Asaei [8] analyzed various electric motors and compared the advantages of each motor with that which is more appropriate for EV deployments. The five basic types of electric engines were explored, including DC, induction, permanent synchronous magnet, switching reluctance, and brushless DC motors. In their study, they found that the induction motor technology had progressed more than the others, and that brushless DC and permanent magnet motors were much more appropriate than others for electric vehicles.

Prud'homme and Koning [9] presented a methodology in the form of a computerized model. It analyzed the expenses and efficiency of an electric vehicle in relation to a fuelpowered vehicle. This was a comparable assessment. It compared an electric automobile

with a conventional car that provides approximately the same kind of service over a similar time. This was done from three main perspectives: customer costs, societal costs, and environmental impacts.

Iclodean et al. [10] demonstrated the flexibility of an electric car using four distinct battery types: lithium-ion (Li-ion), molten salt (Na-NiCl2), nickel metal hydride (Ni-MH), all with a similar reserve capacity of electrical power. The originality of this research was the application in a real-time computerized simulation of four different rechargeable batteries for EVs in a similar model, in order to assess the autonomy and effectiveness of these rechargeable batteries in the driving process.

Oh [11] discussed and determined which drivetrain arrangement was the best to use in a commercially obtainable test motor as a train for hybrid vehicles. The engine feature could be simulated, as well as the actual characteristics evaluated when used in the car for a distinct driving and operating condition. Qiu and Wang [12] carried out extensive research on the structure and operation of the electrically powered regenerative braking component of EVs. The contribution process and assessment methods provided by regenerative braking were addressed and assessed by the circulation of energy to enhance the energy effectiveness of EVs. They presented a methodology for the calculation of the renewable frequency contribution. Furthermore, a novel regenerative braking control approach was presented, termed the "Serial 2 control technique." In addition, as a contrast control approach, two control techniques were provided, namely the "parallel control strategy" and the "serial one control strategy".

Pfeiffer et al. [13] discussed the alternative time delay estimation (TDE) techniques. All options were evaluated by means of real data with EV energy trains. They focused not only on the correctness of the TDE, but also on computing performance to facilitate the operation of vehicle electronic control units (ECUs). Even modest noise, as well as offsets, were found in the measuring data in the recommended linear regression (LR) methodology, which were not suited for our purposes. The variance minimization (VM) technique is a good option. After the initial execution, it is not only noise-proof, but also very effective.

Song [14] presented an integrated framework to assess the consequences of various solutions for power management. Three energy management strategy (EMS) considerations were included in their suggested strategy. The first was the durability of the fuel cell. Fuelsaving was the second priority for assessing fuel efficiency, and was dependent on a dynamic algorithm created for optimal worldwide driving distances. The synthesis of weighted fuel-cell durability was the third priority for the EMS.

Wang et al. [15] presented an assessment indicator system for use patterns focused on data of the battery electric vehicle (BEV) to examine the use of car-sharing vehicles and private vehicles, in order to analyze their usability patterns. The assessment indicator system was built on the state transition strategy and defined the three-dimensional use pattern for BEVs. The time and space components of travels defined the time as and space properties of the pattern of use. The decisive dimension represented a decision-making pattern based on a perceptual psychological model as a reason for the state transformation at the microlevel.

Zhang et al. [16] investigated the requirements for charging stations while considering the plug-in electric vehicle (PEV) operational cost, as well as BEV feasibility. The area of research and PEV specifications were determined depending on the early cars used in the evolving trade market in California. An appropriate charging strategy based on 24 h travel trends was suggested to minimize operating costs. The findings demonstrated that the charging timelines were the main tool in minimizing PEV operating costs, while more charging locations offered to decrease advantages for plug-in hybrid electric vehicles (PHEVs).

This paper is unique in various ways [17–25]. First, in contrast to many other studies, our paper focuses on the expert-centric hierarchical structure for multicriteria decision making in the evaluation of different EVs. Second, this work presents a straightforward

fuzzy-based unified methodology in the form of a computational model. This model helped to compare the efficiency of EVs to that of other types.

#### **3. Different Types of Electric Vehicles**

It is a very interesting opportunity to go shopping for cars, especially for people attempting to improve the ecosystem. The EV industry is changing fast, and one would then probably buy one of those five kinds of electrical vehicles (EVs) if they reached the conclusion that they wanted to buy or rent a car that is better for the atmosphere.

#### *3.1. Battery Electric Vehicles (BEVs)*

BEV denotes a battery electric vehicle that is operated by a battery-powered full electric engine. These are also called pure electric vehicles (PEVs) because they use only electricity as the primary source. The battery in these vehicles must be charged at regular intervals, often by connecting them to a charging station. One of the most significant barriers to BEV acceptance is "range anxiety" [26–33], which occurs when owners are concerned about being stuck in the middle of the highway with a completely depleted battery [17,18]. BEVs are capable of transforming about 80% of the power stored in the batteries into action. Teslas (all variants), the Nissan Leaf, and the Volkswagen e-Golf are a few examples of BEVs. Figure 3 shows the architectural diagram of battery electric vehicles.

**Figure 3.** Architectural diagram of battery electric vehicles (BEV).

### *3.2. Fuel-Cell Electric Vehicles (FCEVs)*

Fuel-cell electric vehicles (FCEVs) are different from other EVs. Fuel-cell EVs are powered by a fuel cell of hydrogen, and do not generate harmful emissions, only water vapor and warm air. In FCEVs, chemical power is transformed into electrical energy in the fuel cell; however, the hydrogen fuel is kept in a storage tank, therefore energy density and range are less likely to be an issue [19]. Like BEVs, FCEVs also primarily feature an electric motor, but employ a different storage and electricity supply technology. The propulsion battery in FCEVs is mostly substituted by the hydrogen tank, as well as by the chemical reaction, in which a number of fuel cells transform hydrogen into electricity as well as water vapor. The Toyota Mirai, Honda Clarity, and Hyundai Nexo are some examples of FCEVs. Figure 4 shows the architectural diagram of fuel-cell electric vehicles.

**Figure 4.** Architectural diagram of fuel-cell electric vehicles (FCEVs).

#### *3.3. Hybrid Electric Vehicles (HEVs)*

Hybrid electric vehicles are the most common type of EV. HEVs include a compact rechargeable battery that is not charged by plugging in, but instead by an inner combustion electric motor and/or the braking mechanism. The HEV is a multienergy system; unlike traditional vehicles that can only generate power, HEV batteries can both generate and absorb electricity. HEVs can already meet the needs of customers and therefore their numbers will increase at a quicker rate in the future. The key difficulty with HEVs is determining how to optimize the many sources of energy in order to achieve the optimum fuel economy or lowest pollution at the lowest cost [20]. There are various types of hybrids; however, on average, most are really battery-assisted automobiles instead of automobiles that are entirely powered by batteries. The Toyota Prius was first released in Japan in the late 1990s, and it made its way to the United States in 2001. Figure 5 shows the architectural diagram of hybrid electric vehicles.

**Figure 5.** Architectural diagram of hybrid electric vehicles (HEVs).
