Gear Ratio Selection Research Articles

Optimizing Gear Ratios for Vehicle Performance Enhancement Using Taguchi Method

Gear ratio is a term used to describe the relationship between the number of teeth on two interlocking gears. It determines the speed and torque of a mechanical system, with higher gear ratios providing more torque but lower speed, while lower ratios offer higher speed but less torque. The study aims to design and develop a 1D vehicle physics model for powertrain matching and fuel economy prediction with the car's performance. For this study, the vehicle is modeled in GT-Suite to predict vehicle performance and fuel economy. The baseline results are compared with the actual testing data with the correlation of each parameter, performance, and fuel economy, which resulted in less than a 3% tolerance difference. The Taguchi method determines the optimal selection of gear ratios, while each gear ratio's significance toward the complete transmission set is calculated using ANOVA. The test subject for this research study is the Proton Saga 1.3L VVT, equipped with a 4-speed automatic transmission. The simulation results show an improvement of 3.36% for standing start acceleration and 3.18% for MDC fuel economy compared to the baseline model. Combining a 1D simulation cycle and statistical analysis approaches is a promising solution for optimizing system performance and fuel economy.

Efficiency Analysis of Electric Vehicles with AMT and Dual-Motor Systems

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.

Optimal gear ratio selection of linear primary permanent magnet vernier machines for wave energy applications

AbstractLinear permanent magnet vernier generators offer a high capability of force density, making them appealing configurations for wave energy harvesting systems. In absolute terms, the performance of these machines is significantly influenced by the selection of slot/pole combinations based on the magnetic gearing effect. For the first time, this paper aims to investigate the impact of different gear ratios on a wide array of linear primary permanent magnet vernier machines (LPPMVMs) with different slot/pole combinations based on fair criteria to offer a more comprehensive understanding of gear ratio selection. To find the optimal number of slots and poles, the response surface methodology is adopted to obtain a robust design and make a fair comparison among LPPMVMs with optimum design characteristics using a cost‐effective approach for the fast and reliable optimisation process. The higher gear ratios result in higher thrust force capability. This will help establishing a new route toward faster develpment of advanced LPPMVMs. The power loss models of LPPMVMs are studied to predict their steady‐state and transient thermal behaviours, verifying their stability and safety, while a simple external forced convection method can be utilised. To verify the model, finite element analysis is exploited to confirm the electromagnetic and thermal analysis results and provide a more exhaustive investigation.

An Analysis The Distinction of Generator and Efficiency Gear Ratio PLTMH Vortex Turbine in Reservoir at Bujel Village

Energy requirements are needed by modern society in this digital era. Today the most widely used energy is fossil energy. It makes fossil energy can run out at any time. Therefore, alternative energy is needed, especially energy from nature. Indonesia has a lot of potential for the development of hydroelectric power plants. It happens because Indonesia has a tropical climate with very high rainfall and many of rivers with a fairly swift flow. The study done at Bujel village in Ngimbang Sub-District, Lamongan. DC generator is superior because the DC generator used is a low rpm generator, so by low rpm can have a higher voltage level of 25V, while AC generator has a maximum voltage of 11V. Based on the standard level of water turbine efficiency of 70%-90%, it means that the second generator can be said to be efficient because the load used is only a 50 Ω. The selection of gear ratios also affects the efficiency value of a water turbine because therefore in this study will examine the difference in gear ratios, namely 46:16, 46:18, 46:20. Considering the test results of the three gears, the gear with a ratio of 46:16 has a high rpm level of 468 rpm.

Multi-Objective Optimization Of Gear Ratios In Two-Speed Dual Clutch Transmissions For Electric Vehicles

The rational matching and optimized design of the gear ratios for the transmission system of an electric vehicle (EV) are of great importance for improving economic and dynamic performances. This paper sets a pure electric vehicle (PEV) as the research object. First, the four common driving cycles considering the urban and suburban areas are selected and analysed which are applied for designing the gear ratios. Second, the parameter matching of the basic indicators of the EV performance and the selection of gear ratios are explored according to the analysis of the four selected driving cycles. Furthermore, gear ratios are set as the variables and the ant colony optimization (ACO) algorithm is applied to optimize the gear ratios by setting the sum of the power demand of the selected common driving cycles, the sum of the average motor efficiency of the chosen driving cycles, and the acceleration time as the objective function in order to optimize the vehicle performances. A two speed dual clutch EV model is constructed in MATLAB/Simulink for verification of the results. The simulation results demonstrate the effectiveness of the optimisation in comparison with the previous gear ratios, where both economic and dynamic performance improvements are evident.

Optimal sizing and energy management of an electric vehicle powertrain equipped with two motors and multi-gear ratios

This paper aims to fully exploit the superior advantages in improving energy economy and dynamic performance of an electric vehicle powertrain equipped with two motors and multi-gear ratios. Considering the dependence of gear ratio selection on motor sizing, a two-loop optimization algorithm, combined by the global search method and non-dominated sorting genetic algorithm-II, is proposed to find optimal motor sizes and transmission ratios. An energy management strategy with novel shift schedules based on the equivalent efficiency of two motors, current engaged gears, and driving conditions is then recommended. The energy management strategy also optimizes the torque allocation to two motors to minimize electricity consumption. Subject to the total of motor peak powers being constant, simulation results for a case study of urban bus show that the optimization of both motor sizes and gear ratios considerably enhances the energy efficiency of powertrain system. In comparison with a single-motor powertrain, optimal motor scales of larger than 0.42 and corresponding gear ratios reduce the electricity consumption significantly by 4.82−5.08%. Besides, the introduced energy management strategy with optimal shift schedules is proved to ensure comparably maximum efficiency while effectively preventing unnecessary and repeated gear changes.

Multi-Speed Gearboxes for Battery Electric Vehicles: Current Status and Future Trends

In the last decade, the automotive industry has undergone a paradigm shift towards electrification. Electric vehicles have become increasingly popular, but so far, they have almost solely utilized single-ratio gearboxes. The use of multiple gear ratios has several potential benefits, including enabling the electric traction machine and inverter to operate in a more efficient region, increasing vehicle acceleration, gradeability, and top speed, and reducing overall traction system mass and volume. Performance vehicles, light to heavy-duty trucks, and buses may especially benefit from multi-speed gearboxes due to their high torque and power requirements. This paper covers the fundamentals of applying multi-speed gearboxes to EVs, the latest designs, and future trends. The efforts of both academia and industry in this field are covered. A range of topics are discussed, including gearbox topologies, gear ratio selection, gearbox losses, noise vibration and harshness, gearbox control, shift scheduling, and regenerative braking. Prior studies are presented showing that depending on the drive cycle, vehicle type, and gearbox configuration, drivetrain energy consumption may be reduced slightly or increased anywhere from a few percent to thirty percent when utilizing a multi-speed configuration. While multi-speed EV traction systems do show considerable promise, more investigation is needed to conclusively determine in what cases they can outperform highly optimized single-speed systems.

Efficient Gear Ratio Selection of a Single-Speed Drivetrain for Improved Electric Vehicle Energy Consumption

The electric vehicle (EV) market has grown over the last few years and even though electric vehicles do not currently possess a high market segment, it is projected that they will do so by 2030. Currently, the electric vehicle industry is looking to resolve the issue of vehicle range, using higher battery capacities and fast charging. Energy consumption is a key issue which heavily effects charging frequency and infrastructure and, therefore, the widespread use of EVs. Although several factors that influence energy consumption of EVs have been identified, a key technology that can make electric vehicles more energy efficient is drivetrain design and development. Based on electric motors’ high torque capabilities, single-speed transmissions are preferred on many light and urban vehicles. In the context of this paper, a prototype electric vehicle is used as a test bed to evaluate energy consumption related to different gear ratio usage on single-speed transmission. For this purpose, real-time data are recorded from experimental road tests and a dynamic model of the vehicle is created and fine-tuned using dedicated software. Dynamic simulations are performed to compare and evaluate different gear ratio set-ups, providing valuable insights into their effect on energy consumption. The correlation of experimental and simulation data is used for the validation of the dynamic model and the evaluation of the results towards the selection of the optimal gear ratio. Based on the aforementioned data, we provide useful information from numerous experimental and simulation results that can be used to evaluate gear ratio effects on electric vehicles’ energy consumption and, at the same time, help to formulate evolving concepts of smart grid and EV integration.

Kit’s development for automation mechanical transmission of a cargo vehicle

The article describes the electric drive design for clutch control. A feature of the developed electric drive is the compensation mechanism use that allowed reducing the electric motor drive power. The developed electric drive controls the car clutch via a standard hydraulic system. The electric hydraulic clutch control does not have a pump and a flow control valve, but it is based on the piston movement in the main clutch cylinder. The main design steps were: determination of the diaphragm clutch spring parameters and operating cycles; choice of the compensation mechanism power characteristics; electric motor and gear ratio selection. The device operation was tested by simulation in a computer programs package. The calculation showed that the use of the compensation mechanism allowed to reduce the electric motor power in the electric drive by 5.7 times. This enabled to decrease energy consumption during the electric drive operation as well as to reduce its dimensions and cost.

Roller test bench with kinematic misalignment of running drums

A roller test bench with a rigid kinematic connection between running drums for testing of wheeled vehicles is studied. A mathematical model of the bench is developed. Its force, kinematic and power analyses were performed. Recommendations on the selection of gear ratios for different types of tests of wheeled vehicles are given. Keywords roller bench, closed loop, running drums, kinematic mismatch, power circulation, bench tests

Model Predictive Controller Development for controlling Actuators of Automated Manual Transmission

Automotive transmission technology is evolving rapidly to match up with the growing need of increased power transfer efficiency, tractive demands and powertrain electrification. In this, Automated Manual Transmission (AMT) systems have made their way to the global market as popular choice by automotive industry. AMT applications have grown substantially in Hybrid Electric Vehicles, where hybrid controller decides optimum gear ratio and the gearshift needs to be automated. Advanced model-based predictive techniques for AMT supervisory controllers have allowed complex clutch control, gear shift control and optimal gear-ratio selection. However, the AMT’s lower level actuator control is usually done with the help of simple linear controllers like PID. This work aims to evaluate the performance of the AMT system when using a Model Predictive Controller (MPC) for controlling generic AMT actuators. This generic AMT and its control system are modeled and implemented within a HEV vehicle closed loop system model. For gearshift control problem, MPC controller is developed and implemented as actuator controller within the AMT control system framework. A simple PID based actuator controller is also developed to serve as benchmark. The comparative performance of the developed MPC and PID based controllers are evaluated by simulating them during gear-shift operation under a realistic drive cycle. Finally, suitability of MPC for the AMT actuator controller is illustrated through the obtained results.

Electric Vehicle with Multi-Speed Transmission: A Review on Performances and Complexities

Electric vehicles (EVs) with multi-speed transmission offer improved performances compared to those with single speed transmission system in terms of top speed, fast acceleration, or gradeability along with driving range. In this study, relevant literature is extensively analyzed to explore the performances and associated complexities with multi-speed automatic manual/mechanical transmission (AMT) system in EVs. In EV powertrain, the only torque generator component is electric motor, which is not equally efficient throughout wider speed range. To the other end, vehicles need to run at different speeds in diverse driving conditions. The study shows that multi-speed transmission system enables efficient operation of electric motor by choosing an appropriate gear at different driving torque-speed demands and thus contributes to achieve desired vehicle performances at minimum energy consumption. To demonstrate the differences, both dynamic and economic performances with multi-gear system and single speed system are compared, and the results of various techniques are presented in the form of tables and bar charts. A quantitative analysis is also conducted to show the performance improvement achievable by employing multi-speed transmission concept in EVs. Apart from additional mass, gear ratio selection and torque interruption during gear shifting are major obstacles to improve drivetrain efficiency and riding comfort in EVs with multi-speed transmission system. For optimal gear ratio in transmission system, genetic algorithm (GA) is found to be implemented in most articles. It is also observed that variable shift schedule needs to be considered during the optimization process to get the paramount gear ratios. Tables and bar charts are used to show the results of recent relevant works to these issues. In this article, the readers would gain a comprehensive knowledge on how multi-speed transmission technology can outperform the single speed system within EV platform and what the inherent challenges are.

Study on force characteristics in accordance with gear ratio of the linear magnetic gear

We have studied linear magnetic gears. Since linear magnetic gears are excellent in terms of ease of manufacture and economy, we studied linear magnetic gears in this paper. The speed and the force of the secondary side of the magnetic gear are determined according to the gear ratio. In additional, the linear magnetic gear also performs a linear reciprocating motion different from the rotary magnetic gear. Therefore, in this paper, the model selection was made through reference works. The selected models had analyzed in accordance with gear ratio.Especially, the characteristics analysis method was compared with total harmonic distortion and force ripple. Also, it is possible to predict and compare the total harmonic distortion, the force ripple, and the speed according to the gear ratio. Finally, the speed comparison between the primary side and the secondary side of the gear ratio was carried out and the validity of the research direction of the linear gear was verified through all the results. All results are important for predicting gear ratio selection of precision linear magnetic gears. Therefore, in this paper, the load force is set opposite to the secondary side, and through this process to obtain accurate results from the analysis of the linear magnetic gear. From the analysis results of this paper, we can analyze the combined model of linear magnetic gear and linear generator.

Design of the laboratory bench for a hydrovolumetric-mechanical transmission of the tracked tractor

Double-flow hydrovolumetric mechanical transmissions is an advanced technical solution that aims to increase productivity, improve efficiency and convenience of control over wheeled and tracked tractors. Their arrangement renders considerable potential for their modernization and makes it possible to introduce recuperation systems that would enhance their performance efficiency coefficient to the level of mechanical transmissions. Innovativeness of these transmissions and the lack of a sufficient number of prototypes largely hinder their implementation in production. A large number of possible HT circuits necessitates the creation of an original bench-prototype for each of them. In order to solve this task, we proposed in this paper a kinematic circuit of the universal testing laboratory bench for HT of the tracked tractor. Its design makes it possible to study HT circuits of the type with a differential «at the output», the type with a differential «at the input» for both wheeled and tracked vehicles, and to simulate the process of work of a hydrovolumetric turning mechanism. Introduction of electric generators to the design makes it possible to estimate in practice the effectiveness of recuperation of kinetic energy at braking, as well as parasite power that circulates in the closed circuit of HT during acceleration and braking. We give quasi-static characteristics of basic HT circuits that are simulated at the laboratory bench. The results were obtained based on an improved mathematical model that makes it possible to determine the volumetric, mechanical, and full performance efficiency coefficient of separate hydraulic machines in the direct and reverse flows of power and special working regions of hydraulic gear. For the transmissions with a differential «at the output», maximal performance efficiency coefficient reaches 83 %, indicating the proper selection of gear ratios and standard size of hydraulic machines. The results obtained are of interest for industrial and design organizations, specializing in the development of transmissions for transportation vehicles. Employing the developed bench would significantly reduce the time between designing and industrial implementation. There is a possibility to confirm experimentally the efficiency and high technical-economic indicators of the proposed transmission. Such a bench will make it possible for scientific institutions to discover new phenomena and processes in HT, systematize the influence of gear ratios of reducers, planetary mechanisms, and their number, on the working processes in HT.

THE EFFECT OF DIFFERENT GEAR RATIO SELECTION ALGORITHMS ON THE EFFICIENCY OF CONVENTIONAL AND PARALLEL HYBRID DRIVETRAINS

Road vehicles using electric power sources have become increasingly popular in the last decade. Meanwhile, battery technology is still not mature enough to meet expected vehicle range; thus the transition from ICE vehicle to fully electric vehicle is not imminent. Therefore the concept of hybrid drivetrain technology was introduced. The hybrid powertrain configuration includes at least two different energy converters together with an energy storage medium. In this article, different gear shifting algorithms were introduced to increase ICE efficiency in conventional vehicle. Besides, a parallel hybrid configuration was also introduced to enhance drivetrain efficiency. The Equivalent Energy Minimization Method (ECMS) and Dynamic Programming (DP) algorithms were selected as online and offline implementable optimal control methods for hybrid power sharing management. Totally six different case studies were planned to compare the efficiency of each configuration. Finally, the effect of the gear ratio selection and power split algorithms were compared on conventional and parallel hybrid drivetrains regarding overall efficiency.

Analysis of an employment of a gear ratio rate in CVT control system

Continuously variable transmissions(CVTs) potentially ensure the selection of such a gear ratio that scooter fuel consumption can reach minimum value. Traditionally these CVT gearboxes are mechanically controlled, causing a gear ratio to be an engine revs function. This solution does not ensure optimum gear ratio. In this paper the solution for fuel optimal control problem is presented. The results obtained during brake stand research of scooter powertrains show the significant values of brake specific fuel consumption for the velocity that is maximum for a scooter according to highway code. With the introduction of CVT gearbox in which the selection of gear ratio can be controlled according to the worked out strategy the solution for fuel consumption problem is possible. Electromechanical actuators ensure the selection of a gear ratio independently of engine revs. Such type of construction solution makes working out the suitable control strategy that ensures decreasing of scooter fuel consumption possible. Presented strategies do not use precise optimization techniques. The CVT efficiency has a strong influence on transient operation. In the paper the control strategy owing to which fuel consumption decreases by over 40% is presented. The strategy was worked out on the basis of fuel consumption map for a defined scooter exploitation model. The possibilities of realization of the worked out strategy were tested on the brake test stand.

Effect of gear ratio on peak power and time to peak power in BMX cyclists

The aim of this study was to ascertain if gear ratio selection would have an effect on peak power and time to peak power production in elite Bicycle Motocross (BMX) cyclists. Eight male elite BMX riders volunteered for the study. Each rider performed three, 10-s maximal sprints on an Olympic standard indoor BMX track. The riders’ bicycles were fitted with a portable SRM power meter. Each rider performed the three sprints using gear ratios of 41/16, 43/16 and 45/16 tooth. The results from the 41/16 and 45/16 gear ratios were compared to the current standard 43/16 gear ratio. Statistically, significant differences were found between the gear ratios for peak power (F(2,14) = 6.448; p = .010) and peak torque (F(2,14) = 4.777; p = .026), but no significant difference was found for time to peak power (F(2,14) = 0.200; p = .821). When comparing gear ratios, the results showed a 45/16 gear ratio elicited the highest peak power,1658 ± 221 W, compared to 1436 ± 129 W and 1380 ± 56 W, for the 43/16 and 41/16 ratios, respectively. The time to peak power showed a 41/16 tooth gear ratio attained peak power in −0.01 s and a 45/16 in 0.22 s compared to the 43/16. The findings of this study suggest that gear ratio choice has a significant effect on peak power production, though time to peak power output is not significantly affected. Therefore, selecting a higher gear ratio results in riders attaining higher power outputs without reducing their start time.

A numerical study of the impact of wet clutch drag torque on the performance of two-speed electric vehicles

In order to study the economy performance of a two-speed electric vehicle (EV) equipped with a wet dual clutch transmission (DCT), this paper presents a theoretical analysis of drag torque in wet clutches, and investigates the relationship between drag torque, transmission gear ratios, and their optimisation. As such, the application of drag torque effects in gear ratio optimisation is conducted. Through this paper mathematic models for a two-speed EV is presented and a procedure to obtain the reasonable optimal gear ratio pairs and corresponding shift schedule for a two-speed EV is described in detail, with consideration of wet clutch drag torque. Through simulation and parametric analysis using different test driving cycles, including constant speed, NEDC and UDDS, the effects of drag torque is studied in gear ratio selection and EV efficiency and economy, with result demonstrating a significant influence on overall vehicle performance, and degradation of drivetrain efficiency.

EFFECT OF GEAR RATIO ON THE DC MOTOR EFFICIENCY OF A MINI-FUEL-CELL VEHICLE CRUISING AT CONSTANT SPEEDS

The traction motor is a key component in a fuel-cell vehicle as it converts electrical energy supplied by a fuel cell into mechanical shaft work for vehicle propulsion. Motor size, torque rating and current consumption are important factors in the selection of the optimum drive motor for best energy efficiency. In a practical power train assembly, the motor is coupled to the wheel via a gearing system. This study focuses on the performance with respect to traction motor efficiency relative to the gear ratio selection and variable drive cycles to minimize the power consumption of the vehicle. A test bench with a 1 kW fuel cell was developed and tests were performed at constant speeds between 15 km/h to 30 km/h with different gear ratios. Among the measured and evaluated parameters using Eagle Tree and Inertia data loggers are rpm, current, torque and power. The results show that the gear ratio selection produces a variation in required motor input power at similar drive speeds. It also shows the optimal setting of the gear ratio of more than 70% that suits the best efficiency point of the DC motor according to actual driving requirements.

Nonlinear Optimal Control of Continuously Variable Transmission Powertrain

Optimization of gear ratio with the objectives of fuel consumption reduction and vehicle longitudinal performance improvement has been the subject of many studies for years. Finding a strategy for changing gears with specific control objectives, especially in the design of vehicles equipped with Continuously Variable Transition system (CVT), which has advantage of arbitrary selection of gear ratio, has been the aim of some recent researches. Optimal control theory has rarely been used in the previous control approaches applied to such systems due to the limitations in the use of fast computational systems. The aim of this study is to design the aforementioned gear ratio change strategy and related control rules on the basis of optimal control. A driver model is also designed for the simulation of driving cycle using MATLAB Simulink Toolbar. Results of implementing optimal control rules in vehicle longitudinal movement simulation with the aim of fuel consumption reduction are finally represented. The presented method has the remarkable advantage of considerable fuel consumption reduction in comparison to other proposed approaches for gear ratio change strategies.