bluuebunny/crossref_metadata_2025 huggingface dataset:
Protection Implementation of Electric Power Steering Based on Functional Safety
Authors: Ye Xiaoming , Yang Yanding , Li Lingyang , Du Jia , Wang Yongliang
Published: April 2024

To reduce the harm caused by the failure of electronic and electrical system, the application of ISO 26262 functional safety standard in the automotive industry is more and more widespread. As a critical safety-related electronic and electrical system in automobile, electric power steering is very important and necessary to meet the requirements of functional safety. This paper introduces the main development activities of functional safety at software level. In order to realize the purpose of freedom from interference in memory, the safety mechanism of memory protection is proposed in software safety analysis. The memory protection is realized in AUTOSAR architecture by configuration.
Modeling and Validation of the Tire Friction on Wet Road
Authors: Zhu Hengjia , Qi Kai , Wang Lliwen , Zhang Wei
Published: April 2024

In order to study the tire friction characteristics under wet skid surface, the “pseudo” hydrodynamic pressure bearing effect is used to be equivalent to the hydrodynamics of water film, and an advanced Lugre tire hydroplaning dynamic model is developed by combining the arbitrary pressure distribution function. The water hydroplaning dynamic tests were carried out for 285/70R19.5 tire under wet of different water film thickness and dry conditions, and the parameters of the advanced Lugre tire dynamic model were identified. The results show that the tire water-skiing model proposed in this paper can effectively simulate the friction characteristics of tires under different water film thicknesses. Under dry conditions, 0.5mm water film and 1mm water film road conditions, the relative errors of the maximum tire friction coefficient between the tested and advanced Lugre tire model are 1.11%, 0.12% and 0.16%, respectively. The root mean square (RMS) relative errors of tire friction coefficients were 4.65%, 0.2% and 0.26%, respectively, and the maximum errors were all less than 5%.
Impacts of Dynamic Toe Angle Variations on Four-Wheel Independent Steering Control and their Optimization Strategies
Authors: Lu Ao , Li Runfeng , Yu Yunchang , Ji Wenfei , Hou Yufeng , Tian Guangyu
Published: April 2024

Compared to traditional vehicles, four-wheel independent drive and four-wheel independent steering (4WID-4WIS) vehicles have gained significant attention from researchers due to their enhanced control flexibility and superior handling performance. The steering angle deviation caused by dynamic toe angle changes in two-wheel steering (2WS) systems is often minimal and hence overlooked. However, the impact becomes notably significant in 4WIS systems. This article contrasts the tire slip angle differences between 2WS and 4WIS, and delves into the effects of dynamic toe angle variations on 4WIS control. Solutions are proposed both in terms of steering angle control and suspension design. Firstly, a dynamic model for the 4WID-4WIS vehicle is established. Secondly, a hierarchical tire force distribution strategy is designed for trajectory tracking. The upper layer utilizes a sliding mode controller and PID controller to determine the total required longitudinal, lateral forces, and yaw moment for tracking. The middle layer allocates these combined forces and moments to individual tires based on constraint optimization, while the lower layer determines vehicle torques and steering angles according to the longitudinal and lateral forces exerted by each tire. In terms of steering control, feedforward control with bump steer compensation is implemented to improve wheel steering precision and lateral tire force control accuracy. Considering the toe angle variations during cornering, critical hardpoint coordinates are identified and optimized through sensitivity analysis in the suspension design, aiming to reduce dynamic toe angle changes. Lastly, the effectiveness of these proposed strategies is validated under constant radius and slalom scenarios using the co-simulation of Carsim and Matlab/Simulink. Simulation results highlight that toe angle changes due to suspension kinematic characteristics play a significant role in 4WIS control. The strategies proposed in this article notably improved tire slip angle errors, demonstrating superior yaw rate responses and lateral tracking accuracy during trajectory following.
Experimental Analysis on Noise and Vibration of Electric Drive System Focusing on Order Contribution Ratio
Authors: Jin Mingxin , Zuo Shuguang , Shi Lei , Mao Qingshao
Published: April 2024

In the process of automobile industrialization, integrated electric drive systems turn to be the mainstream transmission system of electric vehicles gradually. The main sources of noise and vibration in the chassis are from the gear reducer and motor system, as a replacement of engine. For improving the electric vehicles NVH performance, effective identification and quantitative analysis of the main noise sources are a significant basis. Based on the rotating hub test platform in the semi-anechoic chamber, in this experiment, an electric vehicle equipped with a three-in-one electric drive system is taken as the research object. As well the noise and vibration signals in the interior vehicle and the near field of the electric drive system are collected under the operating conditions of uniform speed, acceleration speed, and coasting with gears under different loads, and the test results are processed and analyzed by using the spectral analysis and order analysis theories. Combining the traditional analysis method above, an evaluation process method focusing on the order contribution ratio is proposed, which is employed to quantitatively analyze the main noise sources and guide the focus of noise reduction. The results indicated that the main order contribution sources of noise are the 21st and 42nd orders from the first-stage gear, and the 48th order from the motor. In addition, it is also relatively prominent that the switching frequency component of the inverter in the signal within low-rotational speed. In the speed range of 1000-9600 rpm, the peak value of vibration energy and its change tendency caused by load can be effectively reflected by high contribution proportion of specific orders. It is concluded that the proposed method is equipped to extracting the key sources of vibration problems under various working conditions.
Vibrational Energy Propagation Analysis at Point Joints between Frame and Panel for Vehicle Interior Noise Reduction
Authors: Abe Keisuke , Tanaka Yunosuke , Yamazaki Toru
Published: April 2024

This paper analyzes the mechanism of vibrational energy propagation and panel vibration generation at the point joints between frame and panel which can be applied to reduce the vehicle interior noise. In this study, we focused on the traveling wave in the early stage of propagation before the mode is formed and investigated the mechanism of panel vibration generation due to wave energy propagation and its reduction method.

First, we show theoretically that the out-of-plane component of the transmitted power at the point joint between frame and panel that contributes to panel vibration is associated with frame deformation. Then, we show through numerical verification that panel vibration can be reduced by reducing the transmitted power of the out-of-plane component and explain the effectiveness of the frame-to-panel joint design guidelines based on energy propagation analysis.

Next, this analysis method was applied to the vehicle body FEM model. Assuming road noise, an energy propagation analysis was conducted to reduce panel vibration when the suspension connection point was excited. The instantaneous structural intensity analysis was used to visualize the traveling wave flow to identify the sound panel, and the point joints that contribute to the ERP of that panel section were further identified by calculating the transmitted power of the out-of-plane component. Then, a simple structural modification intended to reduce this transmitted power was made at the point joints, and the panel ERP and interior noise were reduced. In conclusion, this study demonstrates the effectiveness of energy propagation analysis in clarifying the mechanism of vehicle interior noise.
Assessing the Effects of Computational Model Parameters on Aerodynamic Noise Characteristics of a Heavy-Duty Diesel Engine Turbocharger Compressor at Full Operating Conditions
Authors: Huang Rong , Ni Jimin , Wang Qiwei , Yin Qi
Published: April 2024

In recent years, with the development of computing infrastructure and methods, the potential of numerical methods to reasonably predict aerodynamic noise in turbocharger compressors of heavy-duty diesel engines has increased. However, aerodynamic acoustic modeling of complex geometries and flow systems is currently immature, mainly due to the greater challenges in accurately characterizing turbulent viscous flows. Therefore, recent advances in aerodynamic noise calculations for automotive turbocharger compressors were reviewed and a quantitative study of the effects for turbulence models (Shear-Stress Transport (SST) and Detached Eddy Simulation (DES)) and time-steps (2° and 4°) in numerical simulations on the performance and acoustic prediction of a compressor under various conditions were investigated. The results showed that for the compressor performance, the turbulence models and time-step parameters selection were within 3% error of the simulated and experimental values for pressure ratio and efficiency. Under high-efficiency conditions, in a fixed time step, the use of SST could achieve high prediction accuracy in pressure ratio and efficiency. For aerodynamic noise prediction, at both the blade passing frequency and its first order harmonic frequency could obtain the significant peak values of power spectrum density (PSD) for four model parameters. In addition, the turbulence models with 4° time step showed lower PSDs at high frequency (more than 15000 Hz) as compared with the PSDs of 2° time step in volute region under near-surge condition. Therefore, based on the trade-off relationship between computational accuracy and time cost, the SST model combined with the 4° time step was the best choice for the calculation of compressor performance and aerodynamic noise prediction at various conditions.
Parameter Identification of Constitute Model of Glass Fiber Reinforced Polypropylene under Adiabatic Temperature Rise Loads
Authors: Zheng Wei-Jun , Liu Xiao-Ang , Shangguan Wen-Bin , Zhang Qu , Gu Chen-guang
Published: April 2024

To characterize the stress flow behavior of engineering plastic glass fiber reinforced polypropylene (PPGF) commonly used in automotive interior and exterior components, mechanical property is measured using a universal material testing machine and a servo-hydraulic tensile testing machine under quasi-static, high temperature, and high strain rate conditions. Stress versus strain curves of materials under different conditions are obtained. Based on the measured results, a new parameter identification method of the Johnson-Cook (J-C) constitutive model is proposed by considering the adiabatic temperature rise effect. Firstly, a material-level experiment method is carried out for glass fiber reinforced polypropylene (PPGF) materials, and the influence of wide strain rate range, and large temperature span on the material properties is studied from a macroscopic perspective. Then, the model parameters of the J-C constitutive model are identified based on the experimental data, and the influence of the adiabatic temperature rise effect under dynamic tensile conditions is considered. The parameters that can describe the performance of glass fiber-reinforced polypropylene (PPGF) materials are obtained by fitting. Finally, the three-dimensional model of high-speed tension is established using ABAQUS/Explicit finite element software, and calculation is carried out based on J-C model constitutive parameters obtained from the improved identification method. The results show that J-C constitutive model parameters obtained using the improved identification method can describe the stress flow behavior of PPGF materials under large strains, high strain rates, and high temperatures. A method for characterizing the mechanical properties of commonly used engineering plastics in automotive interior and exterior components under high strain rate conditions is established from both experimental and simulation aspects. This method may be used in actual engineering applications.
Analysis of Dual Fuel Hydrogen/Diesel Combustion Varying Diesel and Hydrogen Injection Parameters in a Single Cylinder Research Engine
Authors: Mancaruso Ezio , Rossetti Salvatore , Vaglieco Bianca Maria
Published: April 2024

In the perspective of a reduction of emissions and a rapid decarbonisation, especially for compression ignition engines, hydrogen plays a decisive role. The dual fuel technology is perfectly suited to the use of hydrogen, a fuel characterized by great energy potential. In fact, replacing, at the same energy content, the fossil fuel with a totally carbon free one, a significant reduction of the greenhouse gases, like carbon dioxide and total hydrocarbon, as well as of the particulate matter can be obtained. The dual fuel with indirect injection of gaseous fuel in the intake manifold, involves the problem of hydrogen autoignition. In order to avoid this difficulty, the optimal conditions for the injection of the incoming mixture into the cylinder were experimentally investigated. All combustion processes are carried out on a research engine with optical access. The engine speed has is set at 1500 rpm, while the EGR valve is deactivated. The purpose of this work is to research the minimum amount of diesel fuel, which allows efficient and controlled hydrogen ignition. Starting from the dual fuel conditions investigated in previous works with two injections per cycle, one of the diesel injections was removed. Subsequently, the shift of the start of injection and the reduction of the energizing time of the diesel injection as well as the increase in the delivered mass of hydrogen are analysed. The final aim is to obtain an indicated mean effective pressure equal to the one previously analysed avoiding backfiring phenomena in the manifolds or abnormal engine operation. All the analysed tests are in ultra lean combustion conditions with premixed ratio higher than 95% and equivalence ratio higher than 0.32. From the investigated cases, it can be found that the best combustion efficiency is determined with a diesel start of injection around 10 before top dead centre, while the lowest amount of diesel corresponds to an energizing time of the injector equal to 209μs. Regarding the hydrogen injection in the intake manifold, a dependency on the intake valve timing is highlighted. Hydrogen was prevented from being thrown into the exhaust by starting its supply after the valve crossing; on the other hand, to avoid backfiring phenomena, it is noted that the hydrogen injection has to end prior to the compression phase commences. This information is of particular interest to fulfil engine decarbonisation optimizing the use of hydrogen in compression ignition engines and facilitating CFD analysis of hydrogen combustion in ultra lean conditions.
Combustion Analysis of Hydrogen-DDF Mode Based on OH* Chemiluminescence Images
Authors: Mukhtar Ghazian Amin , Shimogawa Koki , Horibe Naoto , Hayashi Jun , Kawanabe Hiroshi , Morita Gin , Hiraoka Kenji
Published: April 2024

Hydrogen–diesel dual-fuel combustion processes were visualized using an optically accessible rapid compression and expansion machine (RCEM). A hydrogen-air mixture was introduced into the combustion chamber, and a pilot injection of diesel fuel was used as the ignition source. A small amount of diesel fuel was injected as the pilot fuel at injection pressures of 40, 80, and 120 MPa using a common rail injection system. The injection amounts of diesel fuel were varied as 3, 6, and 13 mm3. The amount of hydrogen was manipulated by varying the total excess air ratio (λtotal) at 3 and 4. The RCEM was operated at a constant speed of 900 rpm, and the in-cylinder pressure and temperature at the top dead center (TDC) were set as 5 MPa and 700 K, respectively. The combustion processes were visualized via direct photography and hydroxyl (OH*) chemiluminescence photography using a high-speed camera and an image intensifier. The results indicated that the diesel mixture first ignited near the wall of the piston bowl, and the flame spread in the hydrogen–air mixture. It was also found that a reduced λtotal shortened the combustion duration, with an increased tendency of the heat release rate to shift from a dual peak to a single peak.
Numerical Study of a Six-Stroke Gasoline Compression Ignition (6S-GCI) Engine Combustion with Oxygenated Fuels
Authors: Purushothaman Ashwin Karthik , Ra Youngchul , Ha Kyoung Pyo , Zhu Shengrong , Ullal Ankith
Published: April 2024

A numerical investigation of a six-stroke direct injection compression ignition engine operation in a low temperature combustion (LTC) regime is presented. The fuel employed is a gasoline-like oxygenated fuel consisting of 90% isobutanol and 10% diethyl ether (DEE) by volume to match the reactivity of conventional gasoline with octane number 87. The computational simulations of the in-cylinder processes were performed using a high-fidelity multidimensional in-house 3D CFD code (MTU-MRNT) with improved spray-sub models and CHEMKIN library. The combustion chemistry was described using a two-component (isobutanol and DEE) fuel model whose oxidation pathways were given by a reaction mechanism with 177 species and 796 reactions.

The key advantage of six-stroke engine operation is the ability to switch the combustion mode among kinetical controlled mode (KCM), kinetically-driven mixing control mode (K-MCM) and mixing controlled mode (MCM) in the second power stroke (PS2) providing a wider range of combustion control. The K-MCM mode operation has shown to reduce both soot and NOx emissions substantially at low load (around 7bar IMEP) engine operations. The current work focuses on 6S-GCI engine operation using synthetic fuels at high load engine operation with the constraints on pressure rise rate (<10bar/deg), combustion efficiency (>90%), soot and NOx emissions (<1g/kg fuel). With the constraints met, engine operating conditions at 15 bar IMEP and 2000 rpm were identified as a function of fuel split ratio and injection timings. Parametric study was also performed by varying fuel injection pressure, initial gas temperature at IVC, boost pressure and exhaust gas recirculation ratio. Engine performance and emissions characteristics of parametric variation are presented as well.
Compression Ignition Engine Smoke Emissions at Reduced Ambient Pressures and Temperatures
Authors: Mattson Jonathan , Gibson Joseph , Kweon Chol-Bum , Kim Kenneth , Schroen Erik , Hepp Kyle , Meininger Rik , Clerkin Peter , Kruger Kurt , Musser Marshall , Pope Aaron , Kang Sang-Guk
Published: April 2024

Smoke emission from compression ignition (CI) engines is directly tied to fuel atomization, vaporization, mixing and combustion processes. Engine boundary conditions such as ambient pressures and temperatures, particularly at higher altitudes, have significant impacts on both available ignition energy and on the mixing-controlled combustion process. However, the effects of boundary conditions are difficult to explore without thorough pressure and temperature control of the engine intake air and exhaust gas at higher altitude conditions. The objective of this research is to investigate the relationship between engine smoke emission and engine power in a CI engine fueled with jet fuel at various ambient conditions including higher altitudes. A multi-cylinder compression-ignition engine was operated on a jet fuel at various ambient pressure and temperature conditions, as low as 60 kPa and -12°C, respectively. Single and multi-injection strategies were applied depending on engine power. Detailed analysis was made on in-cylinder pressure, heat release, and the ratio of premixed combustion to mixing-controlled combustion as indicated by the heat release rate. Smoke opacity and filtered smoke number (FSN) measurements were made using an AVL Opacimeter and an AVL Smoke Meter, respectively, at sea level conditions as well as at reduced ambient temperatures and pressures. Depending on the engine power, a shift between premixed and mixing-controlled combustion occurred which significantly impacted the engine-out smoke. Further, the smoke emission was dependent on the injection strategies. Smoke emissions for the jet-fueled engine were examined with respect to heat release behavior and equivalence ratio. The capabilities and challenges of measuring smoke at higher altitude conditions are discussed.
RDE PN Emission Challenges for a China 6 PHEV
Authors: Liu Yi , Li Chunbo , Boger Thorsten , Feng Xiangyu , Li Weiwei , Chen Xiaolang
Published: April 2024

With more stringent CO2 emission regulation in the world, Plug-in Hybrid Electric Vehicle (PHEV, also known as off-vehicle charging hybrid electric vehicle, OVC-HEV) plays a more important role in the current modern market, such as in China. At the same time, Real Driving Emission (RDE) was introduced in both Euro 6d and China 6b regulation, which covers more factors in the real driving practice including altitude, environment temperature, fuel quality, driving behaviors, and so on, which could potentially impact the pollutant emissions. Besides above mentioned, for PHEV, the state of charge (SOC) of the battery is also considered as one important factor, which could impact the engine load and emissions. Thus, this paper discusses some testing results of a PHEV (1.5L MPI engine) from a Chinese OEM, which was tested in the laboratory with different initial SOC points (charge sustaining - CS mode and charge depleting - CD mode) and different environment temperature (230C, 00C & -100C) as well to check their impact to the tail pipe particle number (PN) emission. In addition, one RDE simulation cycle with urban driving only was run at low environment temperature (00C) on the chassis dynamometer and the result of particle number emission above 23nm (PN23) is discussed according to the China 6b and Euro 6e requirement. Particle number emission above 10nm (PN10) from tail pipe is also measured per the new requirement in Euro 7 proposal and potential China 7 regulation. In the end, some relevant possible suggestions to meet the current and the future regulation are also discussed.
FRP Composite Battery Carriers for Commercial Vehicles
Authors: Srivastava Sanjay , Sonkusare Shailesh
Published: April 2024

The current battery carrier for commercial vehicles is made of steel and is designed to hold two batteries weighing approximately 80 kg to 100 kg. However, this battery carrier faces several issues including corrosion, chemical reactivity, high maintenance requirements and its heavy weight. To tackle these challenges, a fiber-reinforced composite battery carrier is designed and developed specifically for commercial vehicles. The objective is to identify a solution that can meet the performance requirements of both static and dynamic loading, thereby reducing the overall weight. The proposed composite battery carrier offers a lightweight design, requires minimal maintenance, possesses high tensile strength and stiffness and is corrosion and chemical resistant. Furthermore, it provides the flexibility to integrate battery cover locking arrangements for added convenience and security. The structure of the composite battery carrier comprises a continuous glass fiber reinforced composite with a polyester resin matrix. Detailed finite element analysis is conducted to ensure optimal performance under static and dynamic conditions. Altair Hypermesh is used for pre-processing, while the Altair OptiStruct solver is utilized for structural analysis, lay-up design and optimization. The laminate design incorporates an orthotropic material model, considering various lay-up configurations. Upon finalizing the lay-up design, a prototype model is manufactured. The manufacturing process employs the Vacuum Bagging Process. As a result, the composite battery carrier achieves a substantial weight reduction of approximately 30% to 50% compared to a steel battery carrier.
Optimized Tapered Roller Bearing Power Loss Equals Deep Groove Ball Bearings in Real-World Electric Vehicle Intermediate Shaft Tests
Authors: Feltman John W.
Published: April 2024

One often reported roadblock to consumer acceptance of electric vehicles is driving range, which is a function of powertrain efficiency and vehicle mass. Electric vehicle gearbox design often is based on multiple parallel shafts, thereby creating significant packaging constraints. Industry perception holds that deep groove ball bearings (DGBB) are more efficient than tapered roller bearings (TRB), and standard spin-loss testing confirms those beliefs. However, spin-loss efficiency testing does not accurately reproduce typical real-world driving. A more realistic comparison of bearing efficiency is required to properly select bearings during the powertrain design stage.

Recently completed testing focused on recreating application conditions (including bearing loads, speeds, misalignment, and load zones) for electric vehicle gearbox intermediate shafts. These conditions varied between TRB and DGBB as a result of application bearing setting and reaction load changes and were faithfully reproduced. Under light load conditions, power loss from a 35 mm DGBB was significantly lower than that of a 35 mm bore TRB, but the TRB power loss was significantly lower than the DGBB’s under heavier loads.

When the individual test conditions were weighted to represent a road-use cycle, weighted power loss was equivalent between the two bearing types at expected vehicle operating temperatures. The bearings had the same rated radial capacity, but the TRB had reduced width, outer diameter (OD), and mass. The TRB’s capability of exhibiting power loss equivalent to the DGBB but within a smaller required envelope size can significantly aid electric vehicle design engineers who are faced with fitting multiple parallel shafts in their applications. In addition, the reduced size of the TRB allows system mass reductions, increasing battery range to address consumer concerns.
Improve the Durability and Maintenance Feasibility of the Universal Joint Based on the Original Half-Shaft Foundation
Authors: Zhang Hengyu , He Li , Xiao Miaoqi
Published: April 2024

Based on the particularity of the racing field of the Baja SAE China, the Baja Racing Team of our university has adopted rzeppa universal joint for vehicle design and field competition in the semi-axle parts of the race car in previous years. In view of the complex conditions of the Baja Competition, such as gravity test, climb test, handling test, endurance test, etc., it is necessary to optimize and develop a more convenient maintenance model. Installation and use of better performance, more suitable for off-road conditions of the shaft. In this paper, based on the development dynamics of automobile axles and the transverse comparison of various axles, a kind of telescopic cross-shaft universal joint axles is designed by using CATIA software to model and simulate kinematics and dynamics by using ANSYS software. At the same time, the stress and strain of the model are continuously optimized according to the change of axle wheel Angle and the torque matching of Baja Racing. The object rotation experiment is designed, and the transmission efficiency of the universal joint of the cross shaft is simulated and analyzed by MATLAB. According to the analysis data and experimental test, the results show that the transmission efficiency, reliability and maintainability of the cross shaft universal joint can fully meet the actual field conditions of the Baja Competition. In addition, this paper also puts forward the optimization scheme and suggestions for improving the transmission efficiency, extending the life and improving the durability of the cross shaft universal joint which may need further research.
Validating the Sun System in Blender for Recreating Shadows
Authors: Barreiro Evan , Carter Neal , Hashemian Alireza
Published: April 2024

Shadow positions can be useful in determining the time of day that a photograph was taken and determining the position, size, and orientation of an object casting a shadow in a scene. Astronomical equations can predict the location of the sun relative to the earth, and therefore the position of shadows cast by objects, based on the location’s latitude and longitude as well as the date and time. 3D computer software have begun to include these calculations as a part of their built-in sun systems. In this paper, the authors examine the sun system in the 3D modeling software Blender to determine its accuracy for use in accident reconstruction. A parking lot was scanned using Faro LiDAR scanner to create a point cloud of the environment. A camera was then set up on a tripod at the environment and photographs were taken at various times throughout the day from the same location in the environment. This environment was then 3D modeled in Blender based on the point cloud, and the sun system in Blender was set up using the date and time of the photographs. The photographs from the environment were then undistorted and aligned to the 3D environment using photogrammetry techniques, and images were rendered in the same positions to compare the shadows in Blender’s Cycles render engine to the photographs. Through this process, the authors determined that Blender’s sun system recreates the sun position adequately, and can be used to accurately determine the location and dimensions of shadows cast by objects of known dimensions and location.
Dummy Positioning at Reclined Seating Position before Impact Testing
Authors: Liu Chongqing , Wang Zhenwen
Published: April 2024

Alongside advancements in automated vehicle technologies, occupants within vehicle compartments are enjoying increased freedom to relax and enjoy their journeys. For instance, reclined seating postures have become more prevalent and comfortable compared to upright seating when Highly Automated Vehicles (HAVs) are introduced. Unfortunately, most Anthropomorphic Testing Devices (ATD) do not support reclined postures.

THOR-AV 50M is a specially designed dummy for reclined postures. As a crucial tool for developing safety restraint systems to protect reclined occupants, the first question is how to position it correctly on a reclined seat before impact testing.

In this study, classical zero gravity seats were selected. H-point coordinators of selected seat at 25°, 40° and 60° seatback angle were measured and compared by using H-point machine (HPM) even though current HPM was not designed for reclined seat. THOR-AV 50M with loosened joints, served to simulate human relaxation fully when seating on a seat, to explore the most comfortable position, there were two ways of seat adjusting from 25° to 40° and 60°, H-point coordinators of THOR-AV 50M at 40° and 60° were measured, related H-point could be regarded as the most comfortable position. By comparing the measured H-point coordinators of THOR -AV 50M and HPM at 40° and 60°, authors found that deviations were within current regulatory requirement. This finding indicated that the target of H-point of THOR-AV 50M at reclined seating position could be pre-defined by HPM. Therefore, a procedure for positioning the dummy in a reclined seat was developed. This paper provides an explanation of the rationale behind the method by using both physical and virtual dummy finite element models. It serves as a valuable reference for potential updates to related standards and protocols to incorporate reclined seating positions in the future, makes up for blanks in automotive industry.
Simulation of Crush Behavior and Energy Absorption of Vehicle Li-Ion Battery Module with Prismatic Cells
Authors: Zhu Feng , Logakannan Krishna , Xu Sida , Sypeck David
Published: April 2024

Lithium-ion batteries serve as the main power source for contemporary electric vehicles. Safeguarding these batteries against damage is paramount, as it can trigger accelerated performance deterioration, potential fire hazards, environmental threats, and more. This study explores damage progression of a commercial vehicle lithium-ion battery module containing prismatic cells under indentation crush loading. We employed computational simulations of mechanical loading tests to investigate this behavior. Physical tests involved subjecting modules to low-speed (0.05 m/s) indentations using a V-shaped stainless-steel wedge, under six unique loading conditions. During the tests, force, and voltage change with wedge displacement were monitored. Utilizing experimental insights, we constructed a finite element model, which included key components of the battery module, such as the prismatic cells, steel frames, and various plastic parts. The finite element model reproduced failure modes observed in the tests, and force-displacement responses, closely. Using this model, we further analyzed energy absorption contributions from battery cells and the stainless steel frame. The findings of this work can help better understand the failure mechanisms of typical vehicle module subject to abuse conditions. Furthermore, they provide valuable guidance for enhancing the safety design of battery systems within electric vehicles, ultimately advancing the reliability and security of electric vehicle technology.
Quality and Affordability by Design in Vehicle Realization
Authors: El-Sayed Mohamed
Published: April 2024

Vehicle quality and affordability will always be the most distinguishing summative characteristics in a fully saturated and highly competitive market. While vehicle quality differentiates between brands in any market segment, affordability remains the key decisive factor for many buyers in each segment. Equally important, affordability is a critical factor in achieving equity in transportation by providing reasonably priced vehicles with quality fitting the needs of different users. Keeping in mind that the cost of quality is usually in conflict with affordability, the main challenge during the different phases of the vehicle design and development process from inception to production becomes the achievement of the multi-objective conflicting goals of maximizing affordability and quality at the same time.

In this paper, guided by quality characteristics framework, that accounts for affordability as a context and structured participation of the customers during the vehicle realization process, the maximization of quality achievements within the preestablished affordability targets throughout the process is studied and discussed. By establishing and monitoring affordability and quality targets by the quality management system along with integrating customers’ participations at critical phases during the realization process from inception to production, the necessary inputs for decision making to deconflict the multi-objective goals of maximizing quality and affordability throughout the product design and development process could be achieved.

To ensure customer satisfaction for quality and stay within targeted affordability, changes to the quality management system and product development process traditional customer participation are proposed. These changes are necessary to integrate affordability as the quality context in the traditional quality management system and include systematic customers’ participation at the end of selected key stages of the vehicle realization. By adding customers’ reviews at critical phases during the realization process, the needed customers’ inputs to achieve the desired vehicle quality within the established tolerances and affordability targets could be achieved.
Study of Braking Characteristics of New Manual Braking System (1st Report)
Authors: Yokoyama Tomohiro , Ogawa Kaito , Soga Masayuki
Published: April 2024

The purpose of this study is to propose braking characteristics that are easy for drivers to handle in a system in which braking and driving operations are performed by hand. Genetic algorithm optimization of braking characteristics showed that the best deceleration tracking was achieved by an FG diagram with a logarithmic function shape. In contrast, the slope of the optimal FG diagram tended to decrease as the driver's proportional gain increased.
Full-Scale Vehicle Burn Test of a 2013 Sedan in a Wildfire Setting
Authors: Papageorge Michael , Knox Benjamin , Colwell Jeff
Published: April 2024

A burn test was conducted to evaluate the propagation of a fire from burning vegetation underneath a vehicle. A 2013 four-door sedan was instrumented with thermocouples throughout the engine compartment, interior, underbody, and trunk as well as a heat flux sensor underneath the vehicle. The vehicle was placed on a bed of straw to simulate a wildland fuel load. The fire was ignited in the vegetation under the engine compartment near the driver-side front wheel. Initially the fire spread outward from the point of origin under the vehicle. As the fire grew, it spread to the engine compartment and travelled through the vegetation outside of the footprint of the vehicle. The fire progressed rearward along the outside of the vehicle while the fire under the engine compartment continued to grow. During the test, the front and rear driver-side doors were opened at t=1.00 min. and t=1.15 min., respectively. At approximately 1.75 min. after ignition, the temperature in the front of the passenger compartment of the vehicle began to increase. By t=1.9 min., the temperature within the passenger compartment of the vehicle was over 600 °C. The fire was extinguished at t=2.33 min. After the fire, the vehicle was examined for potential pathways the fire took to propagate to the vehicle interior. It was observed that the open driver-side doors were the dominant avenue for fire propagation to the interior of the vehicle. The heat flux from the wildland fuel load was measured to be similar to the heat flux measured in a post-collision fire test involving a gasoline pool fire underneath the vehicle.
Unique curved based seat design for better ride comfort
Authors: Bhatnagar Manas , Jain Nishant , Biswal Jyotiranjan , Sharma Ajay
Published: April 2024

Designing an automotive seat, it is required to perform a detailed study of anthropometry, which deals with measurement of human individuals and understanding human physical variations. It also requires application-based movement study of driver’s hands, feet’s & overall body movement. It is very difficult to design seat curvatures based on any static manikin-based software.

We at VECV, have developed a new concept using mixed reality VR technology to capture all body movements for designing best in class seat curvature to accommodate variety of drivers with different body types.

We have designed a specialized static bunk, which has a wide range of seat, steering and ABC paddle adjustments, which are integrated with virtual data. We use to study and capture the data of driving position and other ergonomic postures of wide range of people with different body types on this static bunk according to their comfortable driving posture. In this comfortable driving posture, user is immersed in virtual environment, where we further study different body movements as per different applications. This data is used to design seat curvatures to achieve best driving comfort for long range driving. POC of concept design is completed.
Can pedestrian headform test results reflect the distribution of head injuries in the real world?
Authors: Ye Bin , Liu Yu , Long Yongcheng , Shi Liangliang , Xinming Wan
Published: April 2024

Wrap around distance (WAD) is an important index to evaluate the contact position between pedestrian head and vehicle, and is also one of the key parameters of pedestrian accident reconstruction. The purpose of this paper is to explore whether the pedestrian headform testcan reflect the distribution of head injury in the real world. Firstly, in order to study the distribution of pedestrian head WAD in road accidents in China, a head WAD prediction model was established using logistic regression based on pedestrian height and vehicle collision speed. Secondly, in order to study the distribution of the risk of severe head injuries among pedestrians in accidents, the frequency of pedestrian head impact and the proportion of pedestrian head injury were counted respectively for sedans and SUVs. Subsequently, a risk curve for severe head injuries was constructed based on the head impact frequency and the proportion of severe injuries, utilizing a method that incorporates joint probability. Finally, to investigate the relationship between the headform test results and the distribution of severe head injury risks among pedestrians in road traffic accidents in China, a meticulous regional division of the head WAD was conducted based on the vehicle's front structure. A qualitative comparison was made between the distribution of headform test results in that area and the distribution of pedestrian injuries in the real world within that specific region. The results indicate that the location of pedestrian head impacts is primarily concentrated within the range of WAD 1500 mm to WAD 2300 mm. When pedestrians collide with sedans, the peak frequency of head impact occurs at WAD 1900 mm, whereas in collisions with SUVs, this peak occurs at WAD 1700 mm. In the areas of sedan windshields and A-pillars, as well as the rear portion of SUV hoods and windshield wiper regions, pedestrians' heads are most susceptible to severe injuries. It is noteworthy that within the WAD1000-WAD1500 mm range, the risk of severe head injuries for pedestrians is nearly zero. This study, through the analysis of severe head injury distribution among pedestrians in China, assessed the effectiveness and applicability of The China Insurance Automotive Safety Index (C-IASI) headform test. It provides targeted recommendations for the enhancement of the C-IASI pedestrian assessment protocol and offers crucial reference for optimizing the design of vehicle front structures.
Dynamic Yaw Rate Regulation for Moderate Understeer in Four-Wheel Steering Vehicles with Zero Sideslip Angle
Authors: Guan Yihang , Zhou Hongliang , Jing Houhua , Miao Weiwei
Published: April 2024

The pursuit of maintaining a zero-sideslip angle has long driven the development of four-wheel-steering (4WS) technology, enhancing vehicle directional performance, as supported by extensive studies. However, strict adherence to this principle often leads to excessive understeer characteristics before tire saturation limits are reached, resulting in counter-intuitive and uncomfortable steering maneuvers during turns with variable speeds. This research delves into the phenomenon encountered when a 4WS-equipped vehicle enters a curved path while simultaneously decelerating, necessitating a reduction in steering input to adapt to the increasing road curvature. To address this challenge, this paper presents a novel method for dynamically regulating the steady-state yaw rate of 4WS vehicles. This regulation aims to decrease the vehicle's sideslip angle and provide controlled understeer within predetermined limits. As a result, the vehicle can maintain a zero-sideslip angle during turns with constant speed and exhibit a neutral or slightly understeer behavior during turns with varying speeds. The relationship between vehicle speed, yaw rate, and the understeer gradient is rigorously analyzed, following the definition of the understeer gradient in the Guiggiani’s formulation. Yaw rate is influenced by vehicle speed and steering wheel angle during turns, resulting in a moderate understeer gradient and a slight deviation from the baseline—i.e., the zero-sideslip angle condition. To address this, a regression algorithm is developed to facilitate the realignment of the steady-state yaw rate with the baseline as speed and steering wheel inputs change, thereby maintaining minimal sideslip angles. Simulations validate the proposed method, demonstrating its effectiveness in achieving a moderate understeer gradient and eliminating counter-intuitive and discomforting steering actions. Ultimately, this dynamic regulation of steady-state yaw rate promises to enhance the handling performance
Numerical Simulation of Class 8 Tractor Trailer Geometries and Comparison with Wind Tunnel Data
Authors: Varghese Joel , Wu Yifeng , Jorda Juanos Albert , Saha Rohit , Dhar Sujan
Published: April 2024

This article analyzes the aerodynamic performance of Class 8 tractor-trailer geometries made available by the Environmental Protection Agency (EPA) using CFD simulation. Large Eddy Simulations (LES) were carried out with the CFD package, Simerics-MP+. A Sleeper tractor and a 53-foot box trailer configuration was considered. The configuration featured a detailed underbody, an open-grille under-hood engine compartment, mirrors, and the radiator and condenser. Multiple tractor-trailer variants were studied by adding aerodynamic surfaces to the baseline geometries. These include tank fairings and side extenders for the cabins, two types of trailer skirts, and a trailer tail. The effect of these devices towards reducing the overall vehicle drag was investigated. Mesh generation was carried out directly on the given geometry, without any surface modifications, using Simerics’ Binary-Tree unstructured mesher. Subsequently, simulations were setup considering realistic driving conditions with lateral wind, rotating wheels, and moving floor. The obtained numerical results were then compared with wind-tunnel test data, which highlighted the excellent predictive capabilities of the simulations. These accurate results, as presented in this paper, demonstrate the feasibility of using high fidelity simulation as a tool in the EPA’s SmartWay Verification Program.