Improve Vehicle Performance Research Articles

Multi-Objective Optimization of Gear Ratios of a Seamless Three-Speed Automated Manual Transmission for Electric Vehicles Considering Shift Performance

Multi-speed transmission can greatly improve the power and economic performance of electric vehicles (EVs) compared with single-speed transmission. Gear ratio is the key design parameter of multi-speed transmission. Optimizing gear ratios can further improve vehicle performance. Most of the existing optimization methods of gear ratios take the power and economy of vehicles in gear as the optimization objectives, but rarely consider the shift performance of the transmission, such as shift time, friction, and shift jerk. Considering the shift performance in the process of gear ratio optimization can not only optimize the vehicle performance in gear, but also improve the shift performance of the transmission. Therefore, this paper proposes a multi-objective optimization method of gear ratios considering the shift performance. Firstly, a seamless three-speed automated manual transmission (AMT) of EVs is selected as the research object, the structure and the shift process without power interruption of the three-speed AMT are introduced, and the detailed EV simulation model is established. Then, the multi-objective optimization method of gear ratios considering shifting performance is described. Specifically, the acceleration time, energy consumption, and jerk of the vehicle in gear are taken as the objective functions, and the shift time, clutch friction, and the shift jerk are added to the corresponding objective functions, respectively. Finally, the multi-objective optimization algorithm is used to solve the gear ratio optimization problem. The simulation results show optimization of the gear ratios significantly improves the power, economy, and comfort of the vehicle compared with the original. More importantly, compared with the optimization method without shift performance, gear ratios optimized by the proposed optimization method has better shift performance, and the feasibility of the proposed method is verified by simulations.

Energy recovery strategy optimization of dual-motor drive electric vehicle based on braking safety and efficient recovery

Braking energy recovery technology, which is widely used in new energy vehicles, can extend the endurance range and reduce the wear of hydraulic braking system. However, due to its direct impact on the economy and safety of the vehicle, maximizing the recovery efficiency and coordinating its work with the hydraulic system are essential to improve vehicle performance. In this study, a pure electric vehicle driven by dual-motor is considered, and an optimized energy recovery strategy based on braking safety and efficient recovery is proposed, which not only enhances the energy recovery rate, but also shortens the braking distance. For the motor braking part, a torque optimization strategy with the goal of minimizing the energy loss of the regenerative braking system is proposed to improve energy recovery. Simulation results show that after applying this strategy, compared with the average distribution strategy, the energy recovery rate is increased by 3.35% under WLTC cycles. For the electro-hydraulic compound braking part, a dynamic coordinated control strategy with variable reserved motor braking force is proposed for the first time to reduce the error between the actual braking torque and the target braking torque, and the effectiveness is verified by simulation results under typical conditions.

Integrated Velocity Prediction Method and Application in Vehicle-Environment Cooperative Control Based on Internet of Vehicles

Rapid progress has been gained in the field of advanced communication technologies, which also promote parallel developments in the Internet of Vehicles (IoVs). In this context, vehicle-environment cooperative control can be integrated into next-generation vehicles to further improve the vehicle's performance, in particular energy efficiency. Accurate prediction of future velocity profiles on basis of IoVs can be a critical breakthrough, which can contribute much to vehicle operation efficiency promotion. In this paper, an integrated velocity prediction (IVP) method fully taking advantage of IoVs is proposed and demonstrated through a case study. In the IVP method, both the macroscopically and microscopically predicted velocity profiles are considered. The macroscopic velocity profiles are predicted via traffic flow analysis (TFA) in multi-access edge computing units (MECUs) which are situated alongside the route. Microscopic velocity profiles are forecasted through Mondrian forest (MF) algorithm in the on-board vehicle control unit (VCU). Final velocity prediction is generated through combination of the macroscopic and microscopic profiles in frequency domain in on-board VCU through fast Fourier transform (FFT) and inverse FFT. A case study validates the distinguished performance of IVP method and demonstrates its significant contribution to vehicle performance improvement.

Internal Combustion Engine Starting and Torque Boosting Control System Design with Vibration Active Damping Features for a P0 Mild Hybrid Vehicle Configuration

In order to meet the increasingly stricter emissions’ regulations, road vehicles require additional technologies aimed at the reduction of emissions from the internal combustion engine (ICE). A favorable solution from the standpoint of costs and simplicity of integration is a 48-V electrical architecture utilizing a low-voltage/high-power induction machine, which operates as the so-called engine belt starter generator (BSG) coupled via a timing belt with the ICE crankshaft within a P0 mild hybrid power train and used for starting up and boosting of the ICE power output, as well as for recuperating kinetic energy during vehicle deceleration. The aim of this work was to design a vibration damping system for the belt transmission within the so-called front end accessory drive (FEAD), which couples the BSG with the ICE crankshaft and to test the control system by means of simulations for realistic operating regimes of the P0 mild hybrid power train in order to show the functionality of the proposed approach in terms of mild hybrid vehicle performance improvement. Simulation results have pointed out effective attenuation of belt compliance-related vibrations using the proposed active damping control, with vibration magnitude reduced between three and five times compared to the default case during engine start-up phase. They have indicated the realistic belt slippage effects during engine start-up phase and have illustrated the effectiveness of the FEAD torque boosting capability with 30% gain in acceleration during vehicle launch.

Systematic Approach for Static Steering Effort Reduction through Linkages Optimization in Small Commercial Vehicles (SCV)

The steering system design of a vehicle is of utmost importance as it not only acts as an interface between the driver and the entire vehicle but also is one of the key vehicle sub system which accounts for vehicle overall performance including vehicle handling and stability. With the recent infrastructure development and changes been witnessed in doing commercial vehicle business to hub and spoke and to door to door logistics delivery are expecting improved vehicle performance particularly in small and light commercial vehicles segments (SCV and LCV) where the business demands are more for the movement of vehicle in narrow city lanes and sharp corners. Also, now driver comfort is considered one of the key factors before purchasing any commercial vehicle. Thus, having power steering in SCV’s and LCV’s has not only become a mandate but also the vehicle steering system performance should be such that the driver is easily able to maneuver the vehicle in narrow city lanes and corners. Through this paper a methodology has been derived wherein factors contributing for achieving static lock to lock maneuverability in a power steering vehicle are analyzed without overdesigning the hydraulic power assistance of the vehicle. The approach mainly focuses on LH/RH symmetric hydraulic pressure build up in the system by critically designing the steering system linkages hard points such as drop arm length, drop arm SAP angle, steer arm length, track rod arm’s length. Also, this study ensures that the derived hard points not only enhances hydraulic assistance in the steering system but also ensures vehicle to have least turning circle diameter (TCD) and enhanced tire life by having least Ackermann error.

Wheel Load Torque Emulation for Electric Propulsion Structure using Dual Induction Motors

Electric vehicle is an adaptation of conventional vehicle, with an integration of electrical motors. It seems to be one of the most promising technologies that can lead to significant improvements in vehicle performance and polluting emissions. However, for any vehicle in urban traffic requires regime changes, frequent acceleration, deceleration, and stopping phases, which lead to serious breakdowns. During the above phases, electric motors are continuously being exposed to thermal and mechanical effects.This paper highlights the possibility of representing the wheel load torque emulation of an electric propulsion structure using dual induction motors vector-controlled. The emulation of load torque acting on one of both electric motors placed at the rear wheels of electric vehicle (EV) structure is accomplished by a DC-generator coupled with an induction motor during vehicle drive cycle operation andunpredictable load profiles. Simulation results confirm widely the feasibility and the effectiveness of the proposed emulator scheme of induction motor-based vector-control in the electric vehicle application.

An all-aluminium vehicle's design and feasibility analysis

Vehicle mass reduction is a critical technology objective that's being pursued by various automakers to improve vehicle performance and reduce greenhouse gas emissions. This objective can achieve significant weight loss without compromising other vehicle attributes such as fuel economy and acceleration. The present work reveals some amazing results of about a 20% decrease in the fuel intake and a 10% reduction in CO2 discharges. The frontal and side crash tests show a greater deformation of aluminium than steel but due to its elastic properties, a better riding comfort to the passengers. The properties of Aluminium 6160 and their comparable contrasts with steel clearly suggest a possibility for an increase in usage of aluminium in passenger cars. The current effort adds to the knowledge of aluminium structural and mechanical properties for the creation of all-aluminium vehicles. The goal of developing an all-aluminium car is to minimize fuel consumption while simultaneously improving safety and performance.

Traction Control and Total Driving Force Distribution Strategy for Electric Vehicles with Four in Wheel Motors based on PD-Fuzzy Control

In this paper, a torque distribution control for electric vehicles with an in-wheel motor installed for each wheel is proposed in order to manage the traction operation of the vehicle and avoid slip ratio from reach extreme values while the vehicle moves into slippery surfaces. The driving force control is the main controller in the proposed control system and its consist from two control loop. PD-Fuzzy logic and PI-control are applied as a wheel speed controller in the inner control loop with the aim of improving stability and support the traction operation of the wheels. To retain the total requested driving force, force distribution strategies are obtained when the vehicle moves on the road with a low friction coefficient surface. Also, it works as a yaw moment suppressor when the vehicle runs into split slippery surfaces which improves vehicle performance. The proposed vehicle dynamics and torque distribution control system are simulated using Simulink-MATLAB Program. The results of the simulation demonstrated the effectiveness of the proposed method.

A Review on Lightweight Metal Component Forming and its Application

The present research focused on reviewing forming technology and inspired various method forming processes for different lightweight materials. Nowadays, to improve modern automobiles’ fuel economy while preserving safety and efficiency, advanced materials are essential. Since accelerating a lighter object requires less energy than a heavier one, lightweight materials offer great potential to improve vehicle performance. Innovative forming technologies are discussed concerning each approach and their contribution to lightweight material application. New metal forming methods are implemented to fulfill lightweight material applications in various fields.

Numerical Investigation of a Rectangular Jet Exhausting over a Flat Plate with Periodic Surface Deformations at the Trailing Edge

Multiple competing factors are forcing aircraft designers to reconsider the underwing engine pod configuration typically seen on most modern commercial aircraft. One notable concern is increasing environmental regulations on noise emitted by aircraft. In an attempt to satisfy these constraints while maintaining or improving vehicle performance, engineers have been experimenting with some innovative aircraft designs which place the engines above the wings or embedded in the fuselage. In one configuration, a blended wing concept vehicle utilizes rectangular jet exhaust ports exiting from above the wing ahead of the trailing edge. While intuitively one would think that this design would reduce the noise levels transmitted to the ground due to the shielding provided by the wing, experimental studies have shown that this design can actually increase noise levels due to interactions of the jet exhaust with the aft wing surface and flat trailing edge. In this work, we take another look at this rectangular exhaust port configuration with some notional modifications to the geometry of the trailing edge to determine if the emitted noise levels due to jet interactions can be reduced with respect to a baseline configuration. We consider various horizontal and vertical offsets of the jet exit with respect to a flat plate standing in for the aft wing surface. We then introduce a series of sinusoidal deformations to the trailing edge of the plate of varying amplitude and wave number. Our results show that the emitted sound levels due to the jet–surface interactions can be significantly altered by the proposed geometry modifications. While sound levels remained fairly consistent over many configurations, there were some that showed both increased and decreased sound levels in specific directions. We present results here for the simulated configurations which showed the greatest decrease in overall sound levels with respect to the baseline. These results provide strong indications that such geometry modifications can potentially be tailored to optimize for further reductions in sound levels.

Design and performance improvements of solar based efficient hybrid electric vehicle

Abstract Hybrid energy in electric vehicles has been globally accepted as the fossil fuels will be exhausted by the middle or end of 21st century. The hybrid vehicles have emerged as a major source of clean and renewable energy to support the never-ending demand of vehicles. The main idea of the paper is the use of hybrid energy in working of e-rickshaw, which has become the most favorite area of research in automobile industry, recently. The proposed model is powered by lead-acid battery and this battery is charged by either using electric plug or solar panel. In the present study, hardware model has been analyzed e-rickshaw in terms of different parameters like mileage, charging and discharging time of battery, charging current, discharging current from the performance as well as security point of view. The hardware model has been developed with Photovoltaic (PV) module, capacitor bank, and Arduino circuit. Here, a modified e-rickshaw has been developed which has improved vehicle performance as compared to existing conventional e-rickshaw. The mileage has improved from 80 to 120.61 km and starting current has been reduced from 57 to 41 A on full load conditions. This has enhanced the battery life and Arduino circuit was implemented to enhance security features. The proposed model of e-rickshaw has improved vehicle performance as compared to existing conventional e-rickshaw in terms of mileage, starting current, battery life, and security feature of the vehicle.

Biomimetic Designs for Automobile Engineering: A Review

Automobile engineering often demands creative and innovative concepts to achieve their performance and efficiency targets. However, the strategies used to create these concepts are evolving with time. Recently, heightened attention has been noticed to using biomimetic concepts in the field of automobile design. The studies that apply biomimicry to automobile design often exhibit improvements in vehicle performance and fuel efficiency. Consequently, biomimetic concepts have extended an opportunity to the automobile industry to generate futuristic designs with advanced technology. However, the innovations and inventions in biology are usually published with more complex terminology that is not convenient for the research community working on automobile engineering. Hence, a notable delay is present in transferring the recent discoveries in biology to engineering researches so that they can develop strategies to mimic them. The purpose of this paper is to provide a brief overview of the biomimetic design approaches that have been and can be used in automobile design. In addition, the paper includes a classification of biomimetic concepts, which reveals the current research interests and highlights the areas with a deficit of research that is required to be addressed extensively in the future.

Adaptive event-based robust passive fault tolerant control for nonlinear lateral stability of autonomous electric vehicles with asynchronous constraints

This work solves the robust passive fault-tolerant control problem for autonomous electric vehicles based on an adaptive event triggered mechanism. Firstly, given the system uncertainties from the tire dynamics and the longitudinal speed, the T–S fuzzy model method is used to approximate the vehicle lateral dynamics. Secondly, taking the communication constraints caused by band-limited networks into account, an adaptive event-triggered scheme is introduced in the process of the control design. Moreover, the asynchronous constraint of the weight function between the controller and system is considered. Thirdly, considering that the actuator faults are inevitably encountered in the control system, a robust passive fault-tolerant control method is proposed to improve vehicle performances. Finally, simulations are carried out to illustrate the effectiveness and robustness of the proposed approach.

A novel magneto-rheological fluid dual-clutch design for two-speed transmission of electric vehicles

The dual-clutch transmission (DCT) in electric vehicles can significantly decrease the torque interruption and improve the shifting comfort. The magneto-rheological fluid (MRF) is a kind of intelligent material commonly used for torque transmission devices with high control accuracy and fast response, e.g. MRF clutch. This paper proposes a novel MRF dual-clutch (MRFDC) design for the two-speed transmission of EVs combining the DCT and MRF clutch advantages. The MRFDC is composed of an internal clutch and an external clutch. The two clutches with the same input shaft and different output shaft can shift between two gears by controlling the input current through the coils in the two clutches. The relationship between the input current and the magnetic flux density is obtained by the finite element analysis of the magnetic field under different input current. Theoretical analysis is carried out to estimate the output torque of MRFDC according to the geometric dimensions of MRFDC structure and rheological properties of MRF. The Herschel-Bulkley model is applied to describe the MRF behaviour because the shear rate of MRF is relatively high. The output torque model is built considering the magnetic flux density. Therefore, the relationship between the transmissible torque and applied input current is determined. Finally, the MRFDC model is experimentally verified on the testbed; besides, the transmissible torque tests and response time tests for internal and external MRF clutches are carried out, respectively. The test results agree with the simulation results, and the differences are within 2 N m. It is suggested that the MRFDC can be applied in EVs to improve vehicle performance.

Intelligent Tire Sensor-Based Real-Time Road Surface Classification Using an Artificial Neural Network.

Vehicles today have many advanced driver assistance control systems that improve vehicle safety and comfort. With the development of more sophisticated vehicle electronic control and autonomous driving technology, the need and effort to estimate road surface conditions is increasing. In this paper, a real-time road surface classification algorithm, based on a deep neural network, is developed using a database collected through an intelligent tire sensor system with a three-axis accelerometer installed inside the tire. Two representative types of network, fully connected neural network (FCNN) and convolutional neural network (CNN), are learned with each of the three-axis acceleration sensor signals, and their performances were compared to obtain an optimal learning network result. The learning results show that the road surface type can be classified in real-time with sufficient accuracy when the longitudinal and vertical axis acceleration signals are trained with the CNN. In order to improve classification accuracy, a CNN with multiple input that can simultaneously learn 2-axis or 3-axis acceleration signals is suggested. In addition, by analyzing how the accuracy of the network is affected by number of classes and length of input data, which is related to delay of classification, the appropriate network can be selected according to the application. The proposed real-time road surface classification algorithm is expected to be utilized with various vehicle electronic control systems and makes a contribution to improving vehicle performance.

Wheel torque distribution optimization of four-wheel independent-drive electric vehicle for energy efficient driving

With the help of several in-wheel motors, four-wheel independent-drive electric vehicle (4WIDEV) has tremendous potential to improve vehicle performance. Except for the theme of stability enhancement during the past two decades, energy saving topic becomes more attractive recently. However, it is difficult to achieve stability and economy performance simultaneously. Given the commonly used control method of rigid yaw rate tracking may limit the energy saving potential of 4WIDEV in cornering. Therefore, be different from previous studies which often focus on a sole target, in this paper, a driving energy management strategy for 4WIDEV based on multi-objective online optimization of four-wheel torque distribution is proposed in this paper, which includes weighted yaw rate tracking error into its parameterized control objectives besides electric drive system efficiency, tire slip losses and wheel torque ripple. Meanwhile, for better coordination of stability and economy in different situation, fuzzy logic control is adopted to dynamically adjust the weight of the control objective indexes of the proposed multi-objective online optimization function. Then, a particle swarm optimization algorithm is adopted to solve the optimization function. Finally, the proposed strategy for energy-efficient driving is verified based on the built Simulink and CarSim co-simulation model. The results show that the proposed four-wheel torque distribution strategy based on the multi-objective online optimization is more effective than average distribution strategy and offline optimization strategy.

The influence of gasoline fuel additive on the motorcycle PM0.1 emission factor

Fuel additive has been known to improve vehicle performance by raising the octane number or cleaning the combustion system. The performance enhancement might affect vehicle emission. In this research, we aim to investigate the impact of fuel additives on the PM0.1 emission. The commercial additives were evaluated based on the factory’s recommended concentration for the mixture fuel. The additive effect on the PM0.1 emission was investigated by measuring the PM0.1 concentration emitted by the motor engine operated using fuel with and without additives. The PM0.1 concentrations were measured using a TSI P-TrakTM Ultrafine Particle Counter Model 8525. The exhaust emission was injected into the chamber for 100 seconds for the PM0,1 concentration measurement. The emission factor was calculated by the total PM0.1concentration per the volume of the burned fuels. The result shows that fuel additives reduce the PM0.1 emission factor depending on the type of the additive. additives reduce the PM0.1 emission factor depending on the type of the additive.

Robust Optimal Control for the Vehicle Suspension System With Uncertainties.

The suspension system is an important unit that affects vehicle performance, including handling stability and riding comfort. In order to improve vehicle performances, a novel robust optimal control strategy for the active suspension system in vehicles is proposed. To handle the parameter uncertainties and external random disturbances, the proposed optimal control strategy is designed by using the combination of the linear quadratic regulator (LQR) optimal control and sliding-mode control. First, by using the nominal model of the active suspension system without the uncertain parameters and the external random disturbances, an optimal control performance index is given, and the initial optimal controller is designed by using the LQR control strategy. Then, to handle the parameter uncertainties and the external disturbances, a robust optimal integral sliding-mode control strategy based on the initial optimal controller is designed, which not only can achieve the optimal control objective but also has good robustness to the uncertain parameters and external disturbances. By using the Lyapunov stability theory, stability analysis of the proposed robust optimal integral sliding-mode control strategy is performed. Finally, the collaborative simulation platform based on the Carsim and MATLAB/Simulink is developed. The simulation results illustrate the advantage of the proposed robust optimal control strategy for the suspension system.

Reliability-based design for lightweight vehicle structures with uncertain manufacturing accuracy

Structural lightweight optimization is one of the key themes to continuously improve vehicle performance. However, most of the studies so far have not considered reliability and manufacturing issues brought about by the uncertainty of tolerances in structural lightweight optimization. In this study, a reliability-based design for lightweight vehicle structures with uncertain manufacturing accuracy is proposed. This method can provide not only the optimal design variables but also the maximum allowable deviation range. The main design variables lacking sample information are regarded as interval variables and other design parameters as probabilistic values. A progressive reliability-based design with uncertain manufacturing accuracy is established for lightweight vehicle structures by employing the transformation method of the interval model and the decoupling strategy of the probabilistic model. Firstly, the general test function is used to analyze the accuracy and efficiency of the reliability decoupling method. Then, lightweight optimization models of a classic cantilever beam and two vehicle structures (parking robot frame, energy absorption box) are established respectively, and the effectiveness of the present optimization method is verified. The optimized design results show that the optimal variables and the corresponding maximum allowable deviation range under acceptable manufacturing requirements can be obtained. The requirements for manufacturing accuracy can be reduced by appropriately increasing the deviation range of the design variables, which may lead to a reduction in manufacturing cost. This study aims to provide feasible design options by optimizing lightweight structures considering uncertain manufacturing accuracy.

Transfer Case Clutch Torque Modeling and Validation Under Slip and Overtaken Conditions

Abstract The vehicle transfer case clutch plays an important role for four-wheel drive (4WD) vehicles since the torque transmitted through the clutch determines the amount of traction torque on tires, which is important for vehicle performance. However, the clutch torque measurement is usually unavailable on production vehicles and needs to be estimated accurately to improve vehicle performance. This paper proposes a unified scheme to model clutch output torque under all three conditions: open (no torque output), slipping, and overtaken. Specifically, the clutch torque model under clutch overtaken condition is first investigated using the vehicle longitudinal and tire dynamics. It was found that effective radius of front tires, powered by the transfer case clutch torque, cannot be assumed as constant and should be compensated by vehicle acceleration, while the effective radius of rear tires connected directly to the propulsion system does not need to be compensated. In addition, it was found that torque model under clutch overtaken condition cannot be used under slip condition. As a result, a general clutch torque model is developed for both slip and overtaken conditions with a clutch slip speed compensation, resulting a root-mean-square error percentage (RMSE%) of 6.8% comparing with the experimental measurement data. Note that overtaken torque model is a special case of the general torque model by setting slip speed equal to zero. The general clutch torque model is able to calculate clutch output torque accurately under both slip and overtaken conditions.