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![Figure 1. Maximum torque capacity and efficiency maps of the motor [8].](profile/Md-Ahssan/publication/344436219/figure/fig1/AS:941653846134784@1601519180376/Maximum-torque-capacity-and-efficiency-maps-of-the-motor-8_Q320.jpg)
A novel gearshift scheduling strategy has been framed for a two-speed transmission system in electric vehicles that can save energy during hilly driving and frequently changing driving conditions through efficient electric motor operation. Unlike the traditional approach, the proposed gearshift strategy is based on the preferred vehicle speed range...
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Context 1
... a buffer zone of 10-40% has been maintained between the downshift line and upshift line that will be further optimized through applying an appropriate optimization method in the later part of this paper. Following the above steps, primary gearshift schedules in relation to the vehicle acceleration and road grade have been shown in Figures 5 and 6, respectively. ...
Context 2
... control variable í µí±¢ in Equation (14) includes gear ratios i.e., í µí°ºí µí± , and shift factors i.e., í µí± , for both shifting maps in relation to vehicle acceleration and road grade for the upshift and downshift lines, respectively. Shift factors are introduced in such a way that these would optimize the gearshift lines within the middle region of both gearshift schedule maps i.e., around the 30 km/h to 70 km/h speed range of Figure 5 and around the 20 km/h to 80 km/h speed range of Figure 6. Since gear selection is obvious (i.e., either gear 1 or gear 2) on either side of the middle region of both schedules, these areas have been excluded in the optimization process. ...
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Citations
... Conversely, experimental modeling centers on the motor's characteristics, deriving characteristic parameters like torque, speed, and efficiency through experimental tests. This study employed the experimental modeling method to develop the driving motor model [33]. ...
With the rapid development of automobiles, energy shortages and environmental pollution have become a growing concern. In order to decrease the energy consumption of electric vehicles (EVs), this study aims to improve EV efficiency with AMT and dual-motor systems. Firstly, the paper establishes an Automated Manual Transmission (AMT) model for EVs, which is then simulated using MATLAB R2022a software. In order to eliminate the impact of gear ratio selection, the genetic algorithm is used to optimize the AMT gear ratios. Meanwhile, a dual-motor EV model is constructed, and three different torque distribution schemes are simulated and analyzed. The results indicate that due to the elongation of the energy transmission chain in AMT-equipped EVs, energy losses increase, leading to some improvement in optimized power consumption. However, these EVs remain inferior to those with only a single-stage main reducer. The study also found that the torque distribution based on optimal efficiency further improves results.
... However, the combined optimization of electric motor and gearbox provides the opportunity to investigate the effect of a change in gear ratio on the entire drive system. Reference [11] shows that different gear ratios are ideal for different operating conditions, so this should be taken into account for the operating-point-based optimization. ...
In this paper, a software framework is presented through an application that is able to jointly optimize an electric motor and a gearbox for the design of a drive system for electric vehicles. The framework employs a global optimization method and uses both analytical and finite element method (FEM) models to evaluate the objective functions. The optimization process is supported by a statistical surrogate model, which allows a large reduction of runtime. An earlier version of this framework was only suitable for electric motor optimization. In the application presented in a previous paper, the motor of a belt-driven electric drive system was optimized. In this paper, the optimization of the same drive system is shown, but now with a combined optimization of a gear drive and motor. The objective functions of optimization are minimizing the total loss energy and the weight of the drive system. The optimization results are compared with previous results to demonstrate the further potential of joint optimization.
... A five-speed gearbox is designed for the proposed vehicle in this research, controlled with the help of a shift logic known as a gearbox controller in the MATLAB/Simulink environment. However, two common parameters are used to initiate the gearshift: the vehicle speed and the torque demand or throttle position [43]. The first gear ratio is fixed, and its selection is used to ensure enough hill capability to start the vehicle [44]. ...
Citation: Neamah, H.A.; Dulaimi, M.; Silavinia, A.; Babangida, A.; Szemes, P.T. Development of a Volkswagen Jetta MK5 Hybrid Vehicle for Optimized System Efficiency Based on a Genetic Algorithm. Energies 2024, 17, 1116. https://doi. Abstract: Hybrid electric vehicles (HEVs) have emerged as a trendy technology for reducing over-dependence on fossil fuels and a global concern of gas emissions across transportation networks. This research aims to design the hybridized drivetrain of a Volkswagen (VW) Jetta MK5 vehicle on the basis of its mathematical background description and a computer-aided simulation (MAT-LAB/Simulink/Simscape, MATLAB R2023b). The conventional car operates through a five-speed manual gearbox, and a 2.0 TDI internal combustion engine (ICE) is first assessed. A comparative study evaluates the optimal fuel economy between the conventional and the hybrid versions based on a proportional-integral-derivative (PID) controller, whose optimal set-point is predicted and computed by a genetic algorithm (GA). For realistic hybridization, this research integrated a Parker electric motor and the diesel engine of a VW Crafter hybrid vehicle from the faculty of engineering to reduce fuel consumption and optimize the system performance of the proposed car. Moreover, a VCDS measurement unit is developed to collect vehicle data based on real-world driving scenarios. The simulation results are compared with experimental data to validate the model's accuracy. The simulation results prove the effectiveness of the proposed energy management strategy (EMS), with an approximately 89.46% reduction in fuel consumption for the hybrid powertrain compared to the gas-powered traditional vehicle, and 90.05% energy efficiency is achieved.
... Consequently, dozens of authors have directed their research efforts towards developing gear ratio distribution concepts tailored to modern cars with more powerful engines and transmissions with a greater number of gear ratios [2], [4], [5], [7], [8], [10]. Research findings aimed at clarifying the operation of power units consisting of an electric motor and a singlespeed or multi-speed mechanical transmission appeared concurrently in scientific periodicals [1], [3], [9], [11]. ...
... According to the simulation results, an average reduction in energy consumption over three cycles by 4% relative to energy consumption when simulating movement on the transmission parameters before optimization was established. Also, in another work, the gear ratios of a two-speed gearbox are optimized when simulating the movement of an electric vehicle with NEDC and UDDS driving cycles [9]. It is noted that the simulation result on two driving cycles diverges by no more than 0.02%. ...
Traction battery vehicles (TBV) are currently gaining more and more popularity and are gradually replacing vehicles with ICE and traditional transmissions. The usage of an electric traction drive as part of TBV solves a number of problems that manufacturers of this type of equipment face today: reducing harmful emissions into the atmosphere, reducing noise, used lubricants recycling, and the increase of the energy efficiency. From the point of view of the scientific research, this type of wheeled vehicles is also of high interest due to the large number of problems and tasks that have formed at the moment. It is a common knowledge, that one of the main problematic issues for the TBV is a rather limited range. In cargo electric vehicles and buses, in order to reduce the size and increase the usable volume of the passenger compartment or cargo space, as well as to unify the products of the power unit and drive, there are used the transmissions, which are the combination of mechanical and electrical components with appropriate control systems. The mechanical component includes a gearbox with one or more gear ratios, an inter-wheel differential, axle shafts, bearings and other components. The electrical component is a traction motor located directly in the drive axle (integrated) or on the outside of the crankcase, as well as a voltage converter with a control system and the necessary switching elements. Similar implementations of the driving axles of vehicles with traction batteries are called mechatronic transmissions.
... The multi-disc clutch's friction coefficient is not constant and is dependent on different factors, such as the speed differential between the driving and driven components and the temperature of the clutch surface. Long-term operation of the multi-disc clutch actuator and clutch friction plate results in wear and tear, leading to corresponding changes in the clutch spring stiffness [25][26][27][28][29][30][31][32]. The aforementioned disturbances have a detrimental impact on the drive motor's speed tracking performance, resulting in prolonged clutch slip time or increased vehicle jerk during the gear shift process. ...
Utilizing a two-speed I-AMT (Inverse-Automatic Mechanical Transmission) with a rear friction clutch as the research object, a gear shift strategy was developed to enhance the driving dynamics and comfort of electrical vehicles (EVs). This strategy combines the open-loop clutch position approach with the closed-loop drivetrain approach. proposal for regulating motor velocity. A two-degree-of-freedom (DOF) Smith predictor with feedforward input is developed to monitor the desired speed of the drive motor despite the system's intrinsic time delay and external disturbances. A feedback speed tracking approach is utilized to realize the speed tracking performance with the existence of time delay and external disturbance, while feedforward input is employed to remove the influence of clutch sliding friction on the speed approach of the motor. To ensure the effectiveness of the gear shift approach strategy and the precision of the two DOF Smith approach with the feedforward approach, a comparison of simulation results is performed first. Then, the most challenging working scenario to approach the transmission, downshifting at high throttle, was tested using an I-AMT-equipped lightweight pure electric vehicle. The results of the experiments show that the two-degree-of-freedom (DOF) Smith approach can remove the time-delay effect from the closed-loop approach and that the proposed whole gear shift approach strategy can limit the clutch slippage time to less than 1.5 s, resulting in a smaller shift jerk and ensuring both driving dynamics and riding comfort.
... Recently, Ahssan et al. [22] offered a gearshift strategy that considers both the vehicle speed, acceleration and road grade to select the most appropriate gear. It has been shown that all possible driving conditions can be addressed with this proposed gearshift schedule. ...
... higher compared to that with conventional approaches while this strategy can save around 18% energy on hilly road conditions. It was noticed that the results in [22] were based on a simulation considering large-size electric vehicles. As a relatively novel approach, the three parameter-based gearshift strategy for a two-speed transmission system will be investigated considering both large size and small size electric vehicles under two different traction motors with experimental evidence. ...
... As a relatively novel approach, the three parameter-based gearshift strategy for a two-speed transmission system will be investigated considering both large size and small size electric vehicles under two different traction motors with experimental evidence. On that note, the next section will briefly demonstrate a further review of the guidelines in [22] to develop the primary gearshift schedule considering the multiple combinations of EV powertrains. A simulation as well as experimental results are presented in Section 3. Section 4 is about analyzing the experimental data to validate the simulation results followed by a conclusion in Section 5. ...
This paper proposes a three-parameter gearshift scheduling strategy that has been implemented on both large and small electric vehicles with two-speed transmission systems. The new strategy evaluates vehicle performance under varying driving conditions on flat and hilly roads by assessing the vehicle speed, acceleration, and road grade. A heuristic approach is used to develop two gearshift schedules for vehicle acceleration and road grade, and gradient descent and pattern search methods are applied to optimize the gear ratios and primary gearshift schedules. The results show that the proposed gearshift strategy saves 16.5% of energy on hilly roads compared to conventional approaches. Optimal gearshift schedules for acceleration provide more room for second gear operation, while optimized gearshift schedules for the road grade increase the buffer zone for larger vehicles and allow more space for the second gear operating area. The experimental results validate the proposed approach’s performance for both large and small electric vehicles.
... So apart from optimizing gear ratios, it is wise to consider gearbox automation and the development of an appropriate gearshifting strategy. It is evident that each set of gear ratios corresponds to a specific gearshifting strategy capable of achieving optimal fuel economy (Ahssan et al., 2020). In other words, determining gear ratios and establishing an optimal gearshifting strategy are inherently intertwined when pursuing optimal fuel consumption. ...
... A driving cycle represents the manner in which a vehicle is utilized, encapsulating its speed, acceleration, and path parameters (Achour & Olabi, 2016). At its simplest, it can be understood as the history of motion, specifically the history of a vehicle's speed, acceleration, and road gradient. ...
Introduction/purpose: Tracked vehicles play a vital role across various domains, from military operations to construction and agriculture. This study focuses on improving the efficiency of tracked vehicles by optimizing both gear ratios and gear-shifting strategies while preserving other performance aspects. Methods: The optimization process involves a genetic algorithm for determining optimal gear ratios, considering performance constraints. Furthermore, the paper introduces a gear-shifting optimization algorithm aimed at enhancing fuel economy to the maximum, while allowing for a valid comparison between two sets of gear ratios. Results: Optimizing gear ratios leads to substantial reductions in fuel consumption, as the engine operates within more efficient regions. Additionally, the optimized gear-shifting strategy further enhances efficiency, resulting in a fuel consumption reduction exceeding 12%, when combined with the optimized gear ratios. Conclusions: This paper offers a direct and robust approach for optimizing powertrain gear ratios and gear-shifting strategies in tracked vehicles. The results demonstrate significant improvements in fuel efficiency without compromising other critical vehicle performance parameters.
... По результатам моделирования установлено среднее по трем циклам снижение энергопотребления на 4% относительно энергопотребления при моделировании движения на параметрах трансмиссии до оптимизации. Также в другой работе проводится оптимизация передаточных чисел двухскоростной коробки передач при моделировании движения электромобиля с ездовыми циклами NEDC и UDDS [9]. Отмечено, что результат моделирования на двух ездовых циклах расходится не более, чем на 0,02%. ...
Транспортные средства на тяговых аккумуляторных батареях (ТАБ) в настоящее время набирают все большую популярность и постепенно вытесняют автомобили с ДВС и традиционными схемами трансмиссии. Применение тягового электропривода в составе транспортных средств с ТАБ решает ряд задач, которые на сегодняшней день стоят перед производителями указанного вида техники: уменьшение вредных выбросов в атмосферу, снижение шума, утилизация отработанных смазочных материалов, повышение энергоэффективности. С точки зрения научных исследований данный вид объектов колесной техники также представляет высокий интерес в виду большого количества сформировавшихся на текущий момент проблем и задач. Известно, что одним из основных проблемных вопросов для транспортных средств на тяговых аккумуляторных батареях является достаточно ограниченный запас хода. В грузовых электромобилях и автобусах для уменьшения габаритов и увеличения полезного объема салона или грузового пространства, а также унификации изделий силового агрегата и привода используются трансмиссии, представляющие собой совокупность механической и электрической составляющих с соответствующими системами управления. Механическая составляющая подразумевает собой редуктор с одним или несколькими передаточными числами, межколесный дифференциал, полуоси, подшипники и другие компоненты. Электрической составляющей является тяговый электродвигатель, расположенный непосредственно в составе ведущего моста (интегрированный) или на внешней стороне картера, а также преобразователь напряжения с системой управления и необходимыми элементами коммутации. Подобные реализации ведущих мостов средств с тяговыми аккумуляторными батареями получили наименование мехатронных трансмиссий.
... When the transmission systems in EVs are considered, the multi-gear system is a good solution for drivetrain efficiency but this system may cause some complexities such as the selection of suitable gear ratio and suitable shifting, torque interruption during gear shifting, also additional mass and transmission losses. Efficient operation of the electric motor in different driving conditions (such as ramp climbing) can be satisfied with a two-speed transmission structure [8]. ...
