bluuebunny/crossref_metadata_2025 huggingface dataset:
Data-Driven Battery Lifetime Model Calibration and Analysis for an Electric Vehicle Battery’s Durability Performance
Authors: Lim Youngchul , Edel Zachary , Marker Ethan , Joung Sanghyeok , Kwon Oh Hyun
Published: April 2024

Due to the expense and time commitment associated with extensive product testing, vehicle manufacturers are developing new simulation techniques to verify vehicle component performance with less testing and more confidence in the final product. Battery lifetime is of particular difficulty to predict, since each battery is different and there are many different control scenarios that could be implemented based on the specific requirements of each battery type. In order to solve this problem for a 12V auxiliary lead-acid battery, a battery durability analysis model has been previously adapted from lithium-ion applications, which is capable of verifying the impact of lead-acid battery durability in a short period of time. In this study, calibration tools for this model were developed and are presented here, and durability analysis and verification are performed for the application of new electric vehicles. New control strategies, designed specifically for the auxiliary batteries in electric vehicles, were evaluated and the durability guide standard (current specification within 6%) was met. The current simulation tools are set up based on battery unit tests, and coefficients are adjusted to account for the impact of measurement procedures on measurements in a full, end-to-end, battery lifetime simulation process that takes an engineer from raw data all the way through final lifetime prediction. The tools are built to simulate expected battery life under different environmental and charge control scenarios. EV drive cycles were run to determine whether or not flooded (FLD) or absorbed glass mat (AGM) batteries were more appropriate for the application studied here, and whether each battery type would be able to meet warranty requirements. Results show that an AGM battery would not fail in a 5 year usage interval, and that a FLD battery would not meet the minimum 3 year requirement for the control scenarios used.
Energy Dissipation Characteristics Analysis of Automotive Vibration PID Control Based on Adaptive Differential Evolution Algorithm
Authors: Jie Li , Dou Lei , Zhao Qi , Qiao Bin , Liu Jiayong , Zhang Wei
Published: April 2024

To address the issue of PID control for automotive vibration, this paper supplements and develops the evaluation of automotive vibration characteristics, and proposes a vibration response quantity for evaluating the energy dissipation characteristics of automotive vibration. A two-degree-of-freedom single wheel model for automotive vibration control is established, and the conventional vibration response variables for ride comfort evaluation and the energy consumption vibration response variables for energy dissipation characteristics evaluation are determined. This paper uses the Adaptive Differential Evolution (ADE) algorithm to tune the PID control parameters and introduces an adaptive mutation factor to improve the algorithm's adaptability. Several commonly used adaptive mutation factors are summarized in this paper, and their effects on algorithm improvement are compared. Design a simulation test plan for commonly used B-class road surfaces and a common speed of 60 km/h under urban driving conditions. To demonstrate the ADE-PID control effect of the ADE algorithm tuning, the ADE algorithm is compared with manually tuned PID control and passive suspension under the same simulation conditions. The results show that the adaptive differential evolution algorithm can effectively improve the tuning efficiency of PID control parameters; PID control can effectively improve the vehicle ride comfort, but it makes the vibration energy dissipation characteristics worse; the ADE-PID control proposed in this paper can improve the conventional ride comfort of vehicles and reduce the negative effects on vibration energy dissipation characteristics; the energy dissipation vibration response as a supplement to conventional vibration response is beneficial for expanding the research and application scope of automotive vibration and its control in the past.
Ride Comfort Enhancement of Railway Vehicles Using Magnetorheological Damper
Authors: Ali Shaimaa A. , Metered Hassan , Bassiuny A. M. , Abdel-Ghany A.M.
Published: April 2024

The study investigates the ride comfort of a rail vehicle with semi-active suspension control and its effect on train vertical dynamics. The Harmony Search algorithm optimizes the gains of a proportional integral derivative (PID) controller using the self-adaptive global best harmony search method (SGHS) due to its effectiveness in reducing the tuning time and offering the least objective function value. Magnetorheological (MR) dampers are highly valuable semi-active devices for vibration control applications rather than active actuators in terms of reliability and implementation cost. A quarter-rail vehicle model consisting of six degrees of freedom (6-DOF) is simulated using MATLAB/Simulink software to evaluate the proposed controller's effectiveness. The simulated results show that the optimized PID significantly improves ride comfort compared to passive.
Methodology to Estimate Load Spectra of Autonomous and Highly Automated Vehicles
Authors: Brandes Gerrit , Rebesberger Ron , Sander Marcel , Erxleben Lars , Henze Roman , Küçükay Ferit
Published: April 2024

The knowledge of representative load collectives and duty cycles is crucial for designing and dimensioning vehicles and their components. For human driven vehicles, various methods are known for deriving these load spectra directly or indirectly from fleet measurement data of the customer vehicle operation. Due to the lack of market penetration of highly automated and autonomous vehicles, there is no sufficient fleet data available to utilize these methods. As a result of increased demand for ride comfort compared to human driven vehicles, autonomous vehicle operation promises reduced driving speeds as well as reduced lateral and longitudinal accelerations. This can consequently lead to decreasing operation loads, thus enabling potentially more light-weight, cost-effective, resource-saving and energy-efficient vehicle components. In order to unlock this potential of dedicatedly dimensioned components for autonomous vehicles, a methodology for quantifying the loads in customer operation is required. Therefore, this paper proposes a novel methodology to quantify operation loads of highly automated and autonomous vehicles based on statistical long-term simulation, in which route characteristics, surrounding traffic and vehicle control algorithms are taken into account. The statistical synthesis of driving routes as the basis for further long-term simulation is addressed in detail in this paper. Furthermore, the impact of different lateral and longitudinal control strategies on drivetrain loads of an autonomous vehicle is showcased as an early result of the proposed methodology. Future work required to complete the proposed methodology is addressed in the outlook of this paper. Additional utilization of the driving route synthesis for the validation of autonomous driving functions is pointed out.
Research on Design of Electric Vehicle Sound Synthesis Based on Frequency Shift Algorithm
Authors: Yu Shangbo , Xie Liping , Lu Chihua , Qian Yushu , Liu Zhien , Songze Du
Published: April 2024

The active sound generation systems (ASGS) for electric vehicles (EVs) play an important role in improving sound perception and transmission in the car, and can meet the needs of different user groups for driving and riding experiences. The active sound synthesis algorithm is the core part of ASGS. This paper uses an efficient variable-range fast linear interpolation method to design a frequency-shifted and pitch-modified sound synthesis algorithm. By obtaining the operating parameters of EVs, such as vehicle speed, motor speed, pedal opening, etc., the original sound signal is interpolated to varying degrees to change the frequency of the sound signal, and then the amplitude of the sound signal is determined according to different driving states. This simulates an effect similar to the sound of a traditional car engine. Then, a dynamic superposition strategy is proposed based on the Hann window function. Through windowing and superposition processing of each sound signal segment generated by the algorithm, the coherence and real-time performance of the synthesized engine sound are improved, so that the ASGS can quickly and accurately reflect the driving status of EVs. Finally, through the analysis and verification of the sound quality of the synthesized sound through different parameter adjustments, an engine synthesized sound that satisfies the subjective evaluation of sound quality can be obtained. This paper proposes an effective active sound synthesis algorithm for EVs, which ensures that EVs produce more textured engine sound while emphasizing the timeliness of synthesized sound. It plays an important role in improving pedestrian safety perception and driving experience, and promotes the research and development of ASGS for EVs.
Measurement and Modeling for Creep Groan of a Drum Brake in Trucks
Authors: Zheng Jing-Yuan , Shangguan Wen-Bin , Tang Hao , Lan Wen-biao
Published: April 2024

An experiment is carried out to measure creep groan of a drum brake located in a trailer axle of a truck. The noise nearby the drum brake and accelerations on brake shoes, axle and trailer frame are collected to analyze the occurring conditions and characteristics of the creep groan. A multi-body dynamics model with 1/4 trailer chassis structures is established for analyzing brake component vibrations that generates the creep groan. In the model, the contact force between brake cam and brake shoes, the contact friction characteristics between brake linings and inner circular surface of brake drum, and the properties of chassis structure are included. Dynamic responses of brake shoes, axle and trailer frame during the braking process are estimated using the established model and the responses are compared with the measured results, which validate the model. Three conclusions of measurement and calculation are obtained. (1) The creep groan is usually generated when braking speed is lower than 5km/h and brake pressure changes smoothly. The change of brake pressure causes multiple harmonic vibrations of brake shoes, axle and trailer frame exhibited. (2) The creep groan is generated by stick-slip vibration of contact pair of the brake linings versus the inner circular surface of brake drum, and the vibration is transmitted to the axle through the path of fasteners, welded supports and elastic elements. (3) In this study, the 1st frequency of the collected noise and accelerations are approximately 212 Hz. The 2nd natural frequency of the axle is also close to 212 Hz, indicating that the creep groan is related to structures of chassis system.
Research on the Pollutant Reduction Control for P2.5 Hybrid Electric Vehicles
Authors: Jing Junchao , Liu Yiqiang , Sun Jiazhen , Wang Zhentao , Zhang Junzhi
Published: April 2024

The strategy for emission reduction in the P2.5 hybrid system involves the optimization of engine torque, engine speed, catalyst heat duration, and motor torque regulation in a coordinated manner. In addition to employing traditional engine control methods used in HEV models, unique approaches can be utilized to effectively manage emissions. The primary principle is to ensure that the engine operates predominantly under steady-state conditions or limits its load to regulate emissions levels. The main contributions of this paper are as follows: The first is the optimization of catalyst heating stage. During the catalyst heating stage, the system divides it into one or two stages. In the first stage, the vehicle is driven by the motor while keeping the engine idle. This approach stabilizes catalyst heating and prevents fluctuations in air-fuel ratio caused by speed and load changes that could potentially worsen emissions performance. The second stage corresponds to when the engine-driven vehicle heats up its catalyst. The second is the engine control optimization which includes the idle speed control, the minimum intake pressure controls and the oxygen storage capacity control. The third is the motor control optimization. Motor power or power generation can be employed to restrict or stabilize engine load within a certain range so as not to impact original emission levels due to load variations. Start-stop control may also be implemented during this stage but should avoid frequent start-stop cycles until during catalyst heating phase. To prevent emission deterioration caused by frequent start-stop events during the catalyst heating, the calibration of the power threshold in energy management module becomes necessary for minimizing subsequent restarts of the engine; thereby improving overall emissions performance. Experimental results demonstrate that implementing this emission management control approach reduces fuel consumption by 37.6% compared with the traditional vehicles.
Evaluation of Uncoated Gasoline Particulate Filter Performance for US EPA MY27+ Particulate Mass Emissions Regulation
Authors: Craig Angus , Warkins Jason , Wassouf Bassel , Beall Douglas , Banker Vonda , Madaffari Jr Dominick
Published: April 2024

The gasoline particulate filter (GPF) represents a practical solution for particulate emissions control in light-duty gasoline-fueled vehicles. It is also seen as an essential technology in North America to meet the upcoming US EPA tailpipe emission regulation, as proposed in the “Multi-pollutant Rule for Model Year 2027”.

The goal of this study was to introduce advanced, uncoated GPF products and measure their particulate mass (PM) reduction performance within the existing US EPA FTP vehicle testing procedures, as detailed in Code of Federal Regulations (CFR) part 1066.

Various state-of-the-art GPF products were characterized for their microstructure properties with lab-bench checks for pressure drop and filtration efficiency, then pre-conditioned with an EPA-recommended 1500 mile on-road break-in, and finally were tested on an AWD vehicle chassis-dyno emissions test cell at both 25°C and -7°C ambient conditions. A modern, T3B70, GTDI light-duty truck served as the test vehicle platform for this study.

This report will show that advanced uncoated GPFs can repeatedly demonstrate high PM filtration efficiency, positioning them well as one solution to meet the US EPA proposed 0.5 mg/mile PM limit. ￼
Low-Cost Open-Source Data Acquisition for High-Speed Cylinder Pressure Measurement with Arduino
Authors: Celislami Eduart , Rawashdeh Osamah , DelVescovo Dan
Published: April 2024

In-cylinder pressure measurement is an important tool in internal combustion engine research and development for combustion, cycle performance, and knock analysis in spark-ignition engines. In a typical laboratory setup, a sub crank angle resolved (typically between 0.1o and 0.5o) optical encoder is installed on the engine crankshaft, and a piezoelectric pressure transducer is installed in the engine cylinder. The charge signal produced by the transducer due to changes in cylinder pressure during the engine cycle is converted to voltage by a charge amplifier, and this analog voltage is read by a high-speed data acquisition (DAQ) system at each encoder trigger pulse. The high speed of engine operation and the need to collect hundreds of engine cycles for appropriate cycle-averaging requires significant processor speed and memory, making typical data acquisition systems very expensive.

The objective of this work was to develop an affordable, open-source DAQ system capable of measuring engine in-cylinder pressure with Arduino. Such a system could then be applied to any engine where there is space to install an encoder on the crankshaft, and could be particularly valuable for educators, Formula SAE teams, hobbyists, and engine builders. The DAQ system developed in this work utilized an Arduino DUE microcontroller and was tested on an Armfield CM11-MKII engine test stand with a 0.5o CA resolution absolute crankshaft encoder and Kistler piezoelectric sparkplug transducer and charge amplifier. Analog to Digital (ADC) readings from the Arduino were streamed to an external SD card, enabling storage of hundreds of engine cycles worth of data. The DAQ was found to be capable of acquisition speeds of 100 kHz, and was tested on engine at speeds up to 4000 rev/min, collecting 1000 consecutive engine cycles with low noise and no loss of signal.
3-Dimensional Numerical Simulation and Research on Internal Flow about Different EGR Rates in Venturi Tube of EGR System for a Turbocharged Diesel Engine
Authors: Yang Shuai , Yan Kai , Liu Haifeng , Liu Hairan , Li Tong
Published: April 2024

Exhaust gas recirculation technology is one of the main methods to reduce engine emissions. The pressure of the intake pipe of turbocharged direct-injection diesel engine is high, and it is difficult to realize EGR technology. The application of Venturi tube can easily solve this problem. In this paper, the working principle of guide-injection Venturi tube is introduced, the EGR system and structure of a turbocharged diesel engine using the guide-injection Venturi tube are studied. According to the working principle of EGR system of turbocharged diesel engine, the model of guide-injection Venturi tube is established, the calculation grid is divided, and it is carried out by using Computational Fluid Dynamics method that the three-dimensional numerical simulation of the internal flow of Venturi tube under different EGR rates injection. The flow field state, velocity field, pressure field and exhaust gas concentration parameters of the mixture formed by air and EGR exhaust gas in Venturi tube are analyzed. The calculation results show that the EGR rate has a great impact on the initial pressure recovery effect before the compression section of the Venturi tube. The greater the EGR rate ejection amount, the worse the pressure recovery effect. In order to meet the requirement of large EGR rate, the Venturi diffuser angle should be reduced while keeping the length of the diffuser section unchanged. The diameter of the throat of the mixing section and the diameter of the EGR ejection port can be appropriately increased, the number of ejection ports can also be appropriately increased. This paper also proves that the Venturi tube of the ejector EGR system can overcome the pressure deficit between the exhaust pipe and the intake pipe of the turbocharged direct-injection diesel engine, which verifies the feasibility of the EGR Technology of the turbocharged direct-injection diesel engine through the Venturi tube.
Dynamic Performance Optimization of Ball Joints with Cross Groove for Automotive Driveshaft System
Authors: Zhan Haojing , Wan Lixiang , Wu Xiaoyong , Hou Qiufeng , Shangguan Wenbin
Published: April 2024

The ball joint with cross groove offers both angular and plunging motion. When transmitting the same torque, the cross groove ball joint is lighter than other plunging Constant Velocity Joints (CVJs). It is crucial for the design of the joint and enhancing the contact fatigue life of the raceway to accurately estimate component loads of the ball joints with cross groove. In this study, the transmission efficiency of the joint and the peak value of contact force between ball and the track are used as evaluation indexes for characterizing dynamic performance of the joint. A multibody dynamic model of the joint is established to calculate its dynamic performance. In the model, the contact properties and friction characteristics of the internal structures were modeled, and a nonlinear equivalent spring and damping model was adopted for estimating the contact force. The transmission efficiency loss of the cross groove joint was measured and compared with the calculated values. Taking friction coefficient, pitch radius, ball diameter, pressure angle, raceway inclination angle, and similarity as design variables, the dominate influencing factors on the dynamic performance of the joint were analyzed. A proxy model for estimating transmission efficiency loss and contact force peak of the joint was established based on the established multibody dynamics model of the joint. Using the presented proxy model and the NSGA2 genetic algorithm, and take the five structural parameters of the CVJ as the optimization design variables, and the transmission efficiency and contact force peak of the joint as the optimization objectives, and the optimal solutions of the parameters were obtained.
Energy-Optimal Allocation of a Heterogeneous Delivery Fleet in a Dynamic Network of Distribution and Fulfillment Centers
Authors: Khan Muhammad Waleed , Villani Manfredi , Ahmed Qadeer
Published: April 2024

This paper presents an energy-optimal plan for the allocation of a heterogeneous fleet of delivery vehicles in a dynamic network of multiple distribution centers and fulfillment centers. Each distribution center with a heterogeneous fleet of delivery vehicles is considered as a hub connected with the fulfillment centers through the routes as spokes. The goal is to minimize the overall energy consumption of the fleet while meeting the demand of each of the fulfillment centers. To achieve this goal, the problem is divided into two sub-problems that are solved in a hierarchical way. Firstly, for each spoke, the optimal number of vehicles to be allocated from each hub is determined. Secondly, given the number of allocated delivery vehicles from a hub for each spoke, the optimal selection of vehicle type from the available heterogeneous fleet at the hub is done for each of spokes based on the energy requirement and the energy efficiency of the spoke under consideration. Furthermore, the dynamic nature of the network is also addressed. As the network changes due to the number of demanded or available vehicles, or drop out of distribution center(s) or fulfillment center(s), for example, due to unavailability of a distribution center or no requirement from a fulfillment center, the plan is updated accordingly in the next iteration. To check the effectiveness of the plan, three distribution centers and ten fulfillment centers are considered on a real-world map. The results show that the proposed plan is the most optimal plan in terms of total energy consumption among all the possible plans for the tested scenario.
Typical Acceleration and Speed Profiles for Right-Turn Maneuvers Based on SHRP2 Naturalistic Driving Data
Authors: Flynn Thomas I. , Wilkinson Craig , Siegmund Gunter P.
Published: April 2024

The goal of this study was to use naturalistic driving data to characterize the motion of vehicles making right turns at signalized intersections. Right-turn maneuvers from 13 intersections were extracted from the Second Strategic Highway Research Program (SHRP2) database and categorized based on whether or not the vehicle came to a stop prior to making its turn. Out of the vehicles that did stop, those that were the first and second in line at the intersection were isolated. This resulted in 186 stopped first-in-line turns, 91 stopped second-in-line turns, and 353 no stop turns. Independent variables regarding the maneuver, including driver’s sex and age, vehicle type, speed, and longitudinal and lateral acceleration were extracted. The on-board video was reviewed to categorize the road as dry/wet and if it was day/night. Aerial photographs of the intersections were obtained, and the inner radius of the curve was measured using the curb as a reference. For vehicles that stopped at the intersection, we generated a parametrized lateral and longitudinal acceleration profile. For the vehicles that did not stop prior to making their right turn, parameterized models of the speed and lateral acceleration were calculated. Linear regression models were created to understand the effect of the independent variables listed above for both the stopped and not-stopped data. This research provides valuable insight into the typical accelerations and speeds of vehicles during right-turn maneuvers, and the results are directly applicable to collision reconstructions.
Validation of the PC-Crash Single-Track Vehicle Driver Model for Simulating Motorcycle Motion
Authors: Palmer Jacob , Rose Nathan A. , Smith Connor , Walter Kevin , Hashemian Alireza
Published: April 2024

This paper validates the single-track vehicle driver model available in PC-Crash simulation software. The model is tested, and its limitations are described. The introduction of this model eliminated prior limitations that PC-Crash had for simulating motorcycle motion. Within PC-Crash, a user-defined path can be established for a motorcycle, and the software will generate motion consistent with the user-defined path (within the limits of friction and stability) and calculate the motorcycle lean (roll) generated by following that path at the prescribed speed, braking, or acceleration levels. In this study, the model was first examined for a simple scenario in which a motorcycle traversed a pre-defined curve at several speeds. This resulted in the conclusion that the single-track driver model in PC-Crash yielded motorcycle lean angles consistent with the standard, simple lean angle formula widely available in the literature. The PC-Crash calculations did not account for the width of the motorcycle tires and their influence on the required lean angles. Also, PC-Crash did not utilize counter-steering to generate the initial lean when entering a curved path. Thus, the steering inputs generated by the simulation should not be interpreted as those an actual rider would utilize.

Second, the model was utilized to simulate instrumented real-world driving of a motorcycle around a series of curves. This helped to establish reasonable inputs for the model and demonstrated that the model’s calculated lean angles were reasonable. Again, the results were consistent with the basic lean angle equation, not accounting for the influence of tire width. Steering inputs were not documented for the real-world driving, and so, no comparison was made between the real-world steering inputs and those generated by PC-Crash. However, the model again did not utilize counter-steering to generate lean, and so it is unlikely that the steering inputs generated by PC-Crash would match the real-world steering inputs. Still, the PC-Crash single-track driver model will yield results that are typically adequate for a crash reconstruction or visualization. Reconstructionists generally do not need to know the precise steering inputs used by a motorcycle rider. In instances where a crash could have been caused by a rider leaning their motorcycle to the geometric limit, the results from PC-Crash might need to be adjusted for tire width to ensure accurate conclusions.
An Evaluation of the Bosch Radar-Based Adaptive Cruise Control System on a 2022 Ducati Multistrada V4S
Authors: Fatzinger Edward C. , Gonzaga William
Published: April 2024

Starting in 2021 Ducati introduced a radar based adaptive cruise control (ACC) developed by Bosch. It utilizes a single radar unit on the front of the motorcycle to detect the presence of vehicles ahead, as well as the separation distance. The system is not an automatic emergency braking (AEB) system but does have similar features. The Ducati ACC system does have limitations, some of which are explored in the subject research. Initial testing was conducted to document the engine braking in each gear. Following initial testing, several tests were performed at high closing speeds of over 100 kph. It was determined that at a closing speed of approximately 100 kph the ACC system would not react to a moving vehicle ahead. Additionally, the system will not react to a stopped vehicle or a “swerve-around” stopped vehicle that suddenly appears. Another series of tests were performed while actively following a vehicle at various speeds, with the front vehicle suddenly slowing to a stop and another series suddenly slowing to an approximate 10-20 kph roll. Lastly, a series of tests were conducted where a sudden lane change was made in front of the motorcycle at a closing speed of roughly 20 kph. In most cases, when the ACC system determines the motorcycle needs to slow; first the throttle is rolled off over an average of 0.6 seconds, then roughly 0.1 seconds later the rear brake application starts, after another approximate 0.2 seconds the front brake application starts. The throttle roll-off time was dependent on motorcycle speed, gear and RPM. Acceleration and acceleration rates (jerk) were explored. The peak deceleration rate achieved was about 0.59g.
Biosignal-Based Driving Experience Analysis between Automated Mode and Manual Mode
Authors: Hu Hongyu , Zhang Guojuan , Cheng Ming , Li Zhengyi , He Lei , Su Lili
Published: April 2024

With the rapid development of intelligent driving technology, there has been a growing interest in the driving comfort of automated vehicles. As vehicles become more automated, the role of the driver shifts from actively engaging in driving tasks to that of a passenger. Consequently, the study of the passenger experience in automated driving vehicles has emerged as a significant research area. In order to examine the impact of automatic driving on passengers' riding experience in vehicle platooning scenarios, this study conducted real vehicle experiments involving six participants. The study assessed the subjective perception scores, eye movement, and electrocardiogram (ECG) signals of passengers seated in the front passenger seat under various vehicle speeds, distances, and driving modes. The results of the statistical analysis indicate that vehicle speed has the most substantial influence on passenger perception. The driving mode has a minor effect on the passenger riding experience, while vehicle distance has virtually no impact. Additionally, the study found that average heart rate, average pupil diameter, maximum pupil diameter, and blink frequency can effectively reflect changes in passengers' subjective perception. Furthermore, a stepwise regression analysis was performed on the selected indicators that demonstrated statistical significance. It was discovered that passenger stress levels are positively correlated with average pupil diameter, thus establishing a relationship between passengers' subjective perception and objective physiological indicators. This study contributes to the research on the comfort of automated vehicles and can provide valuable insights for enhancing the acceptance of such vehicles.
Prediction of Aerodynamic Drag in SUVs with Different Specifications by Using Large-Eddy Simulations
Authors: Nagaoka Hiroaki , Yenerdag Basmil , Ambo Kei , Philips David , Ivey Christopher , Brès Guillaume , Bose Sanjeeb
Published: April 2024

Emission regulations are becoming more stringent, as global temperature continues to rise due to the increasing greenhouse gases in the atmosphere. Battery electric vehicles (BEV), which have zero tailpipe emissions, are expected to become widespread to solve this problem. As the powertrain of BEV is more efficient than conventional powered vehicles, the proportion of energy loss during driving due to aerodynamic drag becomes greater. Therefore, reducing aerodynamic drag for improved energy efficiency is important to extend the pure electric range. At Honda, Computational Fluid Dynamics (CFD) and wind tunnel testing are used to optimize vehicle shape and reduce aerodynamic drag. Highly accurate CFD is essential to efficiently guide the development process towards reducing aerodynamic drag. Specifically, the prediction accuracy for the exterior shape, underfloor devices, tires, and wheels must meet development requirements. In this paper, we used the CPU-based moving mesh version of “Fidelity CharLES”, hereafter called “the moving solver”, to calculate aerodynamic drag of SUVs with different shapes and specifications, and compared them with vehicle’s test measurements conducted at Honda’s 5-belt wind tunnel facility. The comparison indicates a good agreement between CFD and test measurements. In particular, the moving solver can predict which configuration yields superior aerodynamic performance given different tire profiles and wheel designs. This was difficult to solve using previous CFD techniques due to the complex flow fields around moving objects and their effects on overall air flow of the vehicle. Furthermore, the moving solver can successfully reproduce the flow field of the test results, such as the wake at the side and behind the vehicle. Calculation times also meet production requirements for the aerodynamic development process.
CAATS - Automotive Wind Tunnel Test Techniques
Authors: Wittmeier Felix , Bianco Antonello , Bratby James , Howard Kevin , Roper Thomas , Senft Victor
Published: April 2024

This paper contributes to the Committee on Commonized Aerodynamics Automotive Testing Standards (CAATS) initiative, established by the late Gary Elfstrom. It is collaboratively compiled by automotive wind tunnel users and operators within the Subsonic Aerodynamic Testing Association (SATA). Its specific focus lies in automotive wind tunnel test techniques, encompassing both those relevant to passenger car and race car development. It is part of the comprehensive CAATS series, which addresses not only test techniques but also wind tunnel calibration, uncertainty analysis, and wind tunnel correction methods.

The core objective of this paper is to furnish comprehensive guidelines for wind tunnel testing and associated techniques. It begins by elucidating the initial wind tunnel setup and vehicle arrangement within it. Subsequently, it delves into a diverse array of test techniques, encompassing aerodynamic force measurements, ventilation drag assessments, flow field analyses, and surface flow visualizations.

A foundational reference point for aerodynamic force measurements is established through the referencing of the WLTP standard. This not only provides a baseline but also outlines prerequisites vital for wind tunnel compliance, guiding the testing process effectively.

Overall, this paper contributes significantly to the understanding and implementation of standardized practices within the realm of automotive wind tunnel testing.
Improving Vehicle Stability and Comfort through Active Corner Positioning
Authors: Skrickij Viktor , Šabanovič Eldar , Kojis Paulius , Žuraulis Vidas , Ivanov Valentin , Shyrokau Barys
Published: April 2024

The emergence of new electric vehicle (EV) corner concepts with in-wheel motors offers numerous opportunities to improve handling, comfort, and stability. This study investigates the potential of controlling the vehicle's corner positioning by changing wheel toe and camber angles. A high-fidelity simulation environment was used to evaluate the proposed solution. The effects of the placement of the corresponding actuators and the actuation point on the force required during cornering were investigated. The results demonstrate that the toe angle, compared to the camber angle, offers more effect for improving the vehicle dynamics. The developed direct yaw rate control with four toe actuators improves stability, has a positive effect on comfort, and contributes to the development of new active corner architectures for electric and automated vehicles.
Research on Lane-Changing Trajectory Planning for Autonomous Driving Considering Longitudinal Interaction
Authors: Chen Jiaqi , Wu Jian , YK Shi
Published: April 2024

Autonomous driving in real-world urban traffic must cope with dynamic environments. This presents a challenging decision-making problem, e.g. deciding when to perform an overtaking maneuver or how to safely merge into traffic. The traditional autonomous driving algorithm framework decouples prediction and decision-making, which means that the decision-making and planning tasks will be carried out after the prediction task is over. The disadvantage of this approach is that it does not consider the possible impact of ego vehicle decisions on the future states of other agents. In this article, a decision-making and planning method which considers longitudinal interaction is represented. The method’s architecture is mainly composed of the following parts: trajectory sampling, forward simulation, trajectory scoring and trajectory selection. For trajectory sampling, a lattice planner is used to sample three-dimensionally in both the time horizon and the space horizon. Three sampling modes which include car following, cruising and lane changing are set up to satisfy different driving requirements. For each trajectory sampled, a forward simulation is used to capture the potential future states of other agents under the ego vehicle’s policy. We then score the trajectory outcomes using a user-defined cost function which has considered comfort, driving efficiency, etc … And the results of the forward simulation in the previous process will also be taken into account in the cost function. Finally, we select the optimal trajectory based on the score. In the simulation process, we simulate the overtaking by lane changing scenario. The result shows that the proposed method can effectively handle multi-agents’ dynamic interaction scenario.
A Study on the Correlation between Heat-Treatment Microstructure and Mechanical Properties of Additive Manufactured Al-Si-Mg Alloy with Bulk and Lattice Structure for Weight Reduction of Vehicle Parts and Application of Shock Absorbing Regions
Authors: Joo Hyomoon
Published: April 2024

This study delves into the microstructural and mechanical characteristics of AlSi10Mg alloy produced through the Laser Powder Bed Fusion (L-PBF) method. The investigation identified optimal process parameters for AlSi10Mg alloy based on Volume Energy Density (VED). Manufacturing conditions in the L-PBF process involve factors like laser power, scan speed, hatching distance, and layer thickness. Generally, high laser power may lead to spattering, while low laser power can result in lack-of-fusion areas. Similarly, high scan speeds may cause lack-of-fusion, and low scan speeds can induce spattering. Ensuring the quality of specimens and parts necessitates optimizing these process parameters. To address the low elongation properties in the as-built condition, heat treatment was employed. The initial microstructure of AlSi10Mg alloy in its as-built state comprises a cell structure with α-Al cell walls and eutectic Si. Heat treatment caused the collapse of the eutectic Si cell walls, and a needle-shaped Mg2Si precipitated phase formed within α-Al. These changes became more prominent with higher heat treatment temperatures and times. Interestingly, increasing heat treatment temperature and time resulted in lower strength but higher ductility in the mechanical properties. Thus, finding optimal heat treatment conditions is crucial to achieving the desired material properties. Furthermore, the study explored the microstructural properties, compression behavior, and energy absorption properties of lattice structures fabricated using the L-PBF method. Leveraging the previously derived optimal process parameters for L-PBFed AlSi10Mg alloy improved internal and surface quality even in thin lattice structures. Analyzing shock absorption characteristics with the application of lattice structures revealed that the L-PBF method's advantage lies in its ability to create complex shapes. This versatility enables incorporating both bulk geometry and lattice structure in a single part using AlSi10Mg alloy. Applying this technique to a shock absorber housing demonstrated excellent durability and achieved a 27% reduction in weight.
Investigation of Propagation of Viruses and Risk of Infection in Automobile Cabins
Authors: Mathur Gursaran
Published: April 2024

The author has developed UV based photocatalytic air purification system (Mathur, 2021, 2122, 2023) that can eliminate all pathogens from the cabin air including COVID-19. In this study, the focus is to determine the risk of infection due to pathogens/germs in the cabin of an automobile. Author has determined the risk of infection by using Wells-Riley model and conducted CFD analysis to determine propagation of virus in cabin as a function of:
1
Cabin Volume & Number of Occupants (Wells-Riley Model in OSA mode): (i) Cabin volume from: Small Sedan, Large Sedan and a SUV; with 4 occupants (males & females); Number of infector 1; Air flowrate (m3/min); (ii) A 15-seater minibus – with 10 occupants (males); Number of infectors 1 & 2; Air flowrate (m3/min)

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CFD to simulate 4 occupants and 1 infector in an automotive cabin – Current investigation is for talking, coughing and sneezing with blower off in Recirc mode wit (i) Infector in the front seat; (ii) Infector in the rear seat.

Based on this investigation, following is a brief summary of the important variables affecting risk of infection: (i) Cabin volume, Cabin air flowrate, Lung capacity – males and females/Number of breath/min, Number of occupants, Number of infectors, Number of quanta; (ii) CFD Analysis: This investigation consists of simulating the propagation of virus laced saliva particles (droplets) coming out from an occupant’s mouth while sitting in the front & rear of the cabin. Occupants (infectors) were simulated by talking, coughing and sneezing through CFD. This was done in recirculation mode with blower on and off. The following are the important finding from this study: Cabin % relative humidity, Cabin internal volume, Seat geometry, Location (front or rear) of the infector (occupant) talking, coughing and sneezing, Occupant (Infector) height.

Detailed analysis has been presented in this paper that will be helpful in developing mitigating strategies to control the spread of virus in an automobile cabin.
Electric vehicle predictive thermal comfort management with solar load estimation
Authors: Hegde Bharatkumar , Haskara Ibrahim , Kaushik Shailendra , Chang ChenFang
Published: April 2024

Electric vehicles (EV) present distinctive challenges compared to ICE (Internal Combustion Engine) powered counterparts. Cabin heating and air-conditioning stand out among them, especially cabin heating in cold weather, owing to its outsized effect on drivable range of the vehicle. Efficient management of the cabin thermal system has the potential to improve vehicle range without compromising passenger comfort. A method to improve cabin thermal system regulation by effectively leveraging the solar load on the vehicle is proposed in this work. The methodology utilizes connectivity and mapping data to predict the solar load over a future time horizon. Typically, the solar load is treated as an unmeasured external disturbance which is compensated with control. It can however be treated as an estimated quantity with potential to enable predictive control. The solar load prediction, coupled with a passenger thermal comfort model, enables preemptive thermal system control over a route. A predictive control architecture is used to generate the HVAC control inputs for actuators of the cabin thermal system based on solar load preview information. This framework effectively leverages connectivity-enabled prediction and establishes novel means to include solar-load in the cabin thermal control. A simulation study is presented to demonstrate the effectiveness of the proposed method in improving temperature regulation performance.
Measurement of Hydrogen Jet Equivalence Ratio using Laser Induced Breakdown Spectroscopy
Authors: Ki Youngmin , Kim Jungho Justin , Lee Seong-Young , Hwang Joonsik , Bae Choongsik
Published: April 2024

Hydrogen exhibits the notable attribute of lacking carbon dioxide emissions when used in internal combustion engines. Nevertheless, hydrogen has a very low energy density per unit volume, along with large emissions of nitrogen oxides and the potential for backfire. Thus, stratified charge combustion (SCC) is used to reduce nitrogen oxides and increase engine efficiency. Although SCC has the capacity to expand the lean limit, the stability of combustion is influenced by the mixture formation time (MFT), which determines the equivalence ratio. Therefore, quantifying the equivalence ratio under different MFT is critical since it determines combustion characteristics. This study investigates the viability of using a Laser Induced Breakdown Spectroscopy (LIBS) for measuring the jet equivalence ratio. Furthermore, study was conducted to analyze the effect of MFT and the double injection parameter, namely the dwell time and split ratio, on the equivalence ratio. Simultaneously, the structural characteristics of the jet were examined within a constant volume chamber to assess the accuracy of the measurement results. The findings indicate that, as MFT lengthens, the width of the jet also increases. This leads to decrease in equivalence ratio in the center of the jet due to enhanced dispersion effects. A decrease in the proportion of first injection and an increase in dwell time lead to jet contraction, resulting in higher local equivalence ratio measured in the center of the jet. The measurement findings of equivalence ratio, integrated with the analysis of the jet, contribute to an increased reliability of LIBS results. Furthermore, these findings reveal the potential for achieving hydrogen lean stratification. This should make a significant contribution towards the advancement of hydrogen engines in the pursuit of achieving carbon neutrality.
Design of a Dual-Motor Powertrain with Magnetorheological Planetary Transmission for Electric Vehicles
Authors: Deng Lei , Zhao Jin , Ning Donghong , Wong Pak , Zhao Jing , Li Weihua
Published: April 2024

The powertrain system plays a crucial role in electric vehicles, exerting significant impact on both the dynamic and economic performances. A breakthrough has been observed by using the dual-motor powertrain system, which outperformed its single-motor counterparts. This study reports a dual-motor powertrain with magnetorheological technology. The powertrain consists of two motors, two magnetorheological brakes and a planetary gear set. Via regulating the brakes, the power transmission flow can be controlled to realise different torque ratios and velocities. The synergetic control of motors and brakes is capable of achieving smooth gear shifting without interruption. This paper details the design of the powertrain system: the structural configuration of the magnetorheological brakes is highlighted, the magnetic field distribution of the brakes under different currents is simulated by COMSOL Multiphysics, and the torque capacities of the brake are also calculated. Future work will focus on the control algorithm development and experimental evaluation of the powertrain system.
Numerical Investigation of a Single Cell (Li-Ion) Combined with Phase Change Material and Additives for Battery Thermal Management
Authors: Srivastav Durgesh , Patil Nagesh Devidas , Shukla Pravesh Chandra
Published: April 2024

Li-ion batteries are commonly used in Electric Vehicles (EVs) due to its high-power density and higher life cycle performance. Individual cells in such battery packs may sometimes lead to thermal runaway conditions under the effect of localized heat generation and faults. Battery liquid cooling methods are normally being employed to resolve this problem with limitations of limited temperature operating range and difficulty in reaching the intricate spaces between the cells. Introducing phase change material (PCM) can mitigate these limitations. The present study deals with a detailed numerical study of a single (Li-ion) cell in ANSYS Fluent using multi-scale multi dimension (MSMD) - Newman, Tiedenann, Gu and Kim (NTGK) model. The single cell model is investigated for the evaluation of its temperatures at varying air velocity surrounding the cell at higher C-rating (load) values. It was observed that the maximum cell surface temperatures were as 322.6, 319.8, 318.1, 316.9, 314.4 and 313.4 K corresponding to 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 m/s for 1.5C discharge rating. Further, the study also involved the investigation of composite PCM based on Paraffin and Vaseline (50:50; CPCM) for improving the cooling performance. It was found that the doping of 2% of Cu in CPCM resulted in ~8°C lower cell surface temperature.