Journal Articles - SAE Mobilus

SAE journals provide rigorously peer-reviewed, archival research by subject matter experts--basic and applied research that is valuable to both academia and industry.

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400Hz High Speed Static Transfer Switch2008-01-287711/11/2024
The objective of this project was to replace electromechanical power line contactors with a Static Transfer Switch (STS) to improve the transfer of electrical power between aircraft generators and decrease required maintenance. The switch requirements include high reliability, lightweight, and high speed (less than 15mS) power transfer. An STS can shorten the bus transfer time to less than the “ride-through” of aircraft electronic loads and therefore have the ability to control and transfer electrical power while maintaining critical mission requirements. The content of this paper and presentation will discuss the initial problem, the research and development approach, design, and initial testing of the STS.
Cooper, Ronald C., Cooper, Evan C.
QA Test - Tatsiana2024-10-0710/1/2024
Testing
Aviation Maintenance Committee
Testing CSP-7232 2024-09-239/22/2024
QA Test
Aviation Maintenance Committee
Test Cycle Simulation of Bench Based on Deep Reinforcement Learning15-17-03-00157/31/2024
Abstract Test cycle simulation is an essential part of the vehicle-in-the-loop test, and the deep reinforcement learning algorithm model is able to accurately control the drastic change of speed during the simulated vehicle driving process. In order to conduct a simulated cycle test of the vehicle, a vehicle model including driver, battery, motor, transmission system, and vehicle dynamics is established in MATLAB/Simulink. Additionally, a bench load simulation system based on the speed-tracking algorithm of the forward model is established. Taking the driver model action as input and the vehicle gas/brake pedal opening as the action space, the deep deterministic policy gradient (DDPG) algorithm is used to update the entire model. This process yields the dynamic response of the output end of the bench model, ultimately producing the optimal intelligent driver model to simulate the vehicle’s completion of the World Light Vehicle Test Cycle (WLTC) on the bench. The results indicate that the algorithm exhibits good convergence in the simulation, throughout the WLTC simulation, the driver always kept the vehicle speed error within 1 km/h, and the response time is less than 0.5 s under the vehicle’s starting condition. In comparison to the PID control algorithm and the model predictive control (MPC) algorithm, it demonstrates smaller speed error and response time, ensuring accuracy, high efficiency, and safety during the indoor vehicle-in-the-loop test.
Gong, Xiaohao, Li, Xu, Hu, Xiong, Li, Wenli
Developing Customer Loss Function for Door Opening Angle in Passenger Cars: Balancing the Ergonomic Performance between “Entry/Exit (Ingress/Egress) Accommodation” and Door Reachability15-17-03-00147/27/2024
Abstract Occupant packaging is one of the key tasks involved in the early architectural phase of a vehicle. Accommodation, as a convention, is generally considered related to a car’s interior. Typical roominess metrics of the occupant like hip room, shoulder room, and elbow room are defined with the door in its closed condition. Several other roominess metrics like knee room, leg room, head room, and the like are also specified. While all the guidelines are defined with doors in their closed condition, it is also important to consider the dynamics that exist while the occupant is entering the vehicle. This article expands the traditional understanding of occupant accommodation beyond conventionally considering the vehicle interior’s ability to accommodate anthropometry. It broadens the scope to include dynamic conditions, such as when doors are opened, providing a more realistic and practical perspective. As a luxury car manufacturer, it is important to ensure the best overall customer experience at each touch point of the vehicle. When the customer enters the vehicle, there should be sufficient space provided by the door opening angle for a comfortable entry. The larger the opening angle, the better is the “entry accommodation” and vice versa. However, a wide-open door also necessitates the customer to bend more, after being seated, to reach its handle and close it. Thus, it becomes a compromise between what is possible as accommodation while the customer is entering the vehicle and how easy it is to close the door after being seated. The same logic holds good while the customer opens the door and exits the vehicle. This article aims to develop a customer loss function (CLF) between the two conflicting criteria by considering relevant anthropometric distribution of customers. This study focuses on driver compartment and the methodology developed is also pertinent to rear compartment with minor adaptations. Since driver’s seating position is heavily dependent on anthropometry, finer details of occupant seating position are also considered in this study. CLF developed in this article will help the designer and packaging engineers in making informed decisions on the door opening angle, by being conscious of the customer loss/gain for defined performance metrics.
Rajakumaran, Sriram, Sreenivas, Kalyan
CSP-7124 testTATSIANA7/17/2024
QA Test
Airlines Electronic Engineering Committee
CSP-7124 QA TestTATSIANAA7/15/2024
QA Testing
Aviation Maintenance Committee
QA Test for CSP-7037053020245/15/2024
QA Test
Airlines Electronic Engineering Committee
Machine-Learning-Accelerated Simulations for the Design of Airbag Constrained by Obstacles at Rest2023-22-00013/4/2024
Abstract Predicting airbag deployment geometries is an important task for airbag and vehicle designers to meet safety standards based on biomechanical injury risk functions. This prediction is also an extraordinarily complex problem given the number of disciplines and their interactions. State-of-the-art airbag deployment geometry simulations (including time history) entail large, computationally expensive numerical methods such as finite element analysis (FEA) and computational fluid dynamics (CFD), among others. This complexity results in exceptionally large simulation times, making thorough exploration of the design space prohibitive. This paper proposes new parametric simulation models which drastically accelerate airbag deployment geometry predictions while maintaining the accuracy of the airbag deployment geometry at reasonable levels; these models, called herein machine learning (ML)-accelerated models, blend physical system modes with data-driven techniques to accomplish fast predictions within a design space defined by airbag and impactor parameters. These ML-accelerated models are evaluated with virtual test cases of increasing complexity: from airbag deployments against a locked deformable obstacle to airbag deployments against free rigid obstacles; the dimension of the tested design spaces is up to six variables. ML training times are documented for completeness; thus, airbag design explorers or optimization engineers can assess the full budget for ML-accelerated approaches including training. In these test cases, the ML-accelerated simulation models run three orders of magnitude faster than the high-fidelity multi-physics methods, while accuracies are kept within reasonable levels within the design space.
Valenzuela del Rio, Jose E., Lancashire, Richard, Chatrath, Karan, Ritmeijer, Peter, Arvanitis, Elena, Mirabella, Lucia
Methodical Design of a Subframe for a Novel Modular Chassis Concept without Knowledge of Final Vehicle Parameters02-17-01-00061/22/2024
Abstract This article presents the methodical development of a subframe for a novel on-the-road-modular vehicle concept, which was developed for the U-Shift project. The subframe serves as the basis for a modular chassis. This chassis offers the possibility to exchange chassis components by the operator, which means after completion by the manufacturer, and thus to adapt the vehicle to different purposes. According to the applied methodology, the relevant wheel loads are determined and a geometric reference model is created. By defining the relevant load cases, the forces acting on the subframe, and thus the physical boundary conditions, can be determined from the wheel loads. In addition to the wheel loads and the geometric boundary conditions, no other vehicle parameters are required for the development of the subframe. The results of the topology optimization are used to identify areas of the geometric reference model that are not exposed to high loads. Based on the results of the topology optimization, a suitable combination of manufacturing processes and suitable materials can also be determined. After the basic topology has been determined, a welded construction is derived from square tubes and plates. Subsequently, excess stresses at critical points are identified in simulation and analysis processes, and constructive changes are made to reduce them. Through validation by simulation of the relevant load cases, a proof of compliance with the physical boundary conditions can be provided. The actually manufactured subframe is presented, and the potential of the modular construction for the development of a chassis modular kit is explained.
Weitz, Fabian, Frey, Michael, Gauterin, Frank
Research on the Secondary Motion of Engine Piston Considering the Transport of Lubricating Oil03-17-03-002411/21/2023
Abstract At present, it is generally considered in the analysis of the secondary motion of engine piston that the piston skirt–cylinder liner friction pair is fully lubricated in an engine operating cycle. However, in practice, when the piston moves upward, the amount of lubricating oil at the inlet may not ensure that the friction pair is fully lubricated. In this article, the secondary motion of piston is studied when the transport of lubricating oil is considered to determine the lubrication condition of piston skirt–cylinder liner friction pair. The secondary motion of piston is solved based on the combined piston motion model, hydrodynamic lubrication model, asperity contact model, and lubricating oil flow model. The secondary motion equation of piston is solved by the Broyden method. The hydrodynamic lubrication equation is solved by the finite difference method. The asperity contact between piston skirt and cylinder liner is calculated by the Greenwood model. The flow of lubricating oil is analyzed based on the theory of fluid mechanics. The results indicate that, when the actual transport of lubricating oil is considered to determine the lubrication condition of piston skirt–cylinder liner friction pair, the secondary motion of piston is remarkably different from that in which the flooded lubrication is assumed in an engine operating cycle. Therefore, it is helpful to improve the accuracy and make the analysis closer to the actual engine operating situation that the transport of lubricating oil is considered in the analysis of the secondary motion of engine piston.
Liu, Jihai, Sun, Jun
Emergency Obstacle Avoidance Trajectory Planning Method of Intelligent Vehicles Based on Improved Hybrid A*10-08-01-000111/14/2023
Abstract In this article, we present a spatiotemporal trajectory planning algorithm for emergency obstacle avoidance. Utilizing obstacle and driving environment data from the sensing module, we construct a 3D spatiotemporal grid map. This informs our improved hybrid A* algorithm, which identifies collision-safe, dynamically feasible trajectories. The traditional hybrid A* algorithm is enhanced in three significant ways to make the search practical and feasible: (1) optimizing search efficiency with motion primitives based on child node acceleration, (2) integrating collision risk into the heuristic function to reduce ineffective node exploration, and (3) introducing a One-Shot search based on the Optimal Boundary Value Problem (OBVP) to improve goal state searches. Finally, the algorithm is tested in two scenarios: (1) a vehicle cut-in from an adjacent lane and (2) a pedestrian crossing. Simulation results indicate that our proposed emergency obstacle avoidance trajectory planning method can efficiently devise trajectories that not only circumvent obstacles safely and adhere to vehicle dynamics constraints, but also meet the real-time demands of emergency obstacle avoidance trajectory planning.
Chen, Guoying, Yao, Jun, Gao, Zhenhai, Gao, Zheng, Zhao, Xuanming, Xu, Nan, Hua, Min
Friction Performance Analysis of Mine Wet Multi-Disc Brake02-17-01-000110/28/2023
Abstract This article takes the wet multi-disc brake used in mining Isuzu 600P as the research object, establishes a simplified three-dimensional model of its key components through SOLIDWORKS and imports it into ANSYS Workbench to establish the flow field and structure field model of the wet brake. Based on the fluid–solid coupling, the finite element simulation of the temperature field and stress field of the friction pair of the wet brake under different braking pressures, braking initial speeds, and fluid viscosities was carried out, and then the position changes of the friction pairs at high temperature hot spots and high stress points were analyzed to determine the stability of its friction performance. Finally, by comparing the temperature change curves of the same point during the braking process under different braking conditions, the validity of the finite element analysis results is verified. The results show that the flow field pressure inside the wet brake is opposite to the flow field velocity, the initial braking velocity is the most influential factor on the friction performance of the friction pair, affected by the fluid, the maximum equivalent stress of the groove between the core plates is the same as the braking force. Pressure, braking initial speed, and fluid viscosity are proportional.
Zhang, Chuanwei, Jin, Xiaohe, Zhao, Dawei, Liu, Jinpeng
Recurrent Neural Network Model for On-Board Estimation of the Side-Slip Angle in a Four-Wheel Drive and Steering Vehicle15-17-01-00039/23/2023
Abstract A valuable quantity for analyzing the lateral dynamics of road vehicles is the side-slip angle, that is, the angle between the vehicle’s longitudinal axis and its speed direction. A reliable real-time side-slip angle value enables several features, such as stability controls, identification of understeer and oversteer conditions, estimation of lateral forces during cornering, or tire grip and wear estimation. Since the direct measurement of this variable can only be done with complex and expensive devices, it is worth trying to estimate it through virtual sensors based on mathematical models. This article illustrates a methodology for real-time on-board estimation of the side-slip angle through a machine learning model (SSE—side-slip estimator). It exploits a recurrent neural network trained and tested via on-road experimental data acquisition. In particular, the machine learning model only uses input signals from a standard road car sensor configuration. The model adaptability to different road conditions and tire wear levels has been verified through a sensitivity analysis and model testing on real-world data proves the robustness and accuracy of the proposed solution achieving a root mean square error (RMSE) of 0.18 deg and a maximum absolute error of 1.52 deg on the test dataset. The proposed model can be considered as a reliable and cheap potential solution for the real-time on-board side-slip angle estimation in serial cars.
Giuliacci, Tiziano Alberto, Ballesio, Stefano, Fainello, Marco, Mair, Ulrich, King, Julian
Applications of Neural Networks to Metallic Flexor Geometry Optimization of Flat Wipers15-17-01-00029/9/2023
Abstract In recent years, demands of flat wipers have rapidly increased in the vehicle industry due to their simpler structure compared to the conventional wipers. Procedures for evaluating the appropriate metallic flexor geometry, which is one of the major components of the flat wiper, were proposed in the authors’ previous study. However, the computational cost of the aforementioned procedures seems to be unaffordable to the industry. The discrete Winkler model regarding the flexor as the Euler–Bernoulli beam is established as the mathematical model in this study to simulate a flexor compressed against a surface at various wiping angles. The deflection of the beam is solved using a finite difference method, and the calculated contact pressure distributions agree fairly with those based on the corresponding finite element model. Flexor designs are paired with various windshield surfaces to accumulate a sufficiently large simulation database based on the mathematical model. An artificial neural network (ANN) approach is developed to predict contact pressure distributions of the flexor much faster than the mathematical model. Geometry of the curved surface is represented by a shape code obtained via a principal component analysis (PCA) and used in the ANN model. The ANN algorithm is also applied to efficiently evaluate the wiping patterns according to the simulated contact pressure distributions. These patterns are then classified by using a convolutional neural network (CNN) to identify several suitable flexor designs for the specific windshield. The flat wiper suggested by the current procedures is experimentally validated to justify its qualified wiping performances.
Chu, Yi-Tzu, Huang, Ting-Chuan, Liao, Kuo-Chi
Exploring the Benefits of Karanja-Oil-Derived Biodiesel-Water Emulsion as a Potential Fuel for Diesel Engines Operated with High-Pressure Fuel Injection Systems03-17-01-00037/21/2023
Abstract Biodiesel is a suitable alternative to diesel because of its carbon neutrality, renewability, lubricity, and lower pollutant emissions. However, extensive research indicates higher oxides of nitrogen (NOx) emissions with biodiesel. A practical method to combat this problem is utilizing water and biodiesel as emulsions. The effect of biodiesel-water emulsion in high-pressure fuel injection systems is not fully explored in the existing literature. The present study addresses this research gap by utilizing biodiesel-water emulsions in a modified light-duty diesel engine. The governor-controlled injection system was adapted to a fully flexible electronic system capable of high-pressure injection. Unlike other literature studies, the fuel injection timings were optimized with biodiesel-water emulsions to maximize brake thermal efficiency (bte) at every load condition. In a novel attempt, the biodiesel source, i.e., raw Karanja oil (RKO), a triglyceride, was utilized as the surfactant to stabilize the biodiesel-water emulsions containing 6%, 12%, and 18% water. The emulsions reduced the ignition delay and cylinder pressures, with less-intense premixed combustion and a more significant diffusion phase combustion than biodiesel. The emulsions also present a delayed combustion phasing following the injection timing trends. Among the tested emulsions, at 5.08 bar brake mean effective pressure (BMEP), 18% biodiesel-water emulsion resulted in an 18% reduced brake specific fuel consumption (bsfc), 5% increase in bte, 30% and 7% mitigation in NOx and smoke levels, with an increase of 10% and 28% for unburned hydrocarbon (HC) and carbon monoxide (CO) emissions.
Gowrishankar, Sudarshan, Krishnasamy, Anand, Aidhen, Indrapal Singh
Topological Optimization of Non-Pneumatic Unique Puncture-Proof Tire System Spoke Design for Tire Performance15-17-01-00017/18/2023
Abstract Non-pneumatic tires (NPTs) have been widely used due to their advantages of no occurrence of puncture-related problems, no need of air maintenance, low rolling resistance, and improvement of passenger comfort due to its better shock absorption. It has a variety of applications as in earthmovers, planetary rover, stair-climbing vehicles, and the like. Recently, the unique puncture-proof tire system (UPTIS) NPT has been introduced for passenger vehicles segment. The spoke design of NPT-UPTIS has a significant effect on the overall working performance of tire. Optimized tire performance is a crucial factor for consumers and original equipment manufacturers (OEMs). Hence to optimize the spoke design of NPT-UPTIS spoke, the top and bottom curve of spoke profile have been described in the form of analytical equations. A generative design concept has been introduced to create around 50,000 spoke profiles. Finite element model (FEM) model is developed to evaluate the stiffness and damage-resisting performance of NPT-UPTIS spoke. The FEM methodology has also been validated with average accuracy of more than 95% for experimental vertical stiffness for commercial NPT-Tweel. The stiffness and damage-resisting performance of generated designs have been predicted with the help of machine learning regression models, which were trained on the FEM results of 200 such designs. These 50,000 generated designs have been categorized in four different categories based on different level of stiffness and damage resistance performance. In this study, one optimized design from each category has been selected and their performance have been validated with 3D FEM simulation. It has been found that the suggested topology optimization approach is efficient to generate UPTIS spoke designs with having ±30% stiffness with 17%, 40%, and 56% more damage resistance performances with respect to the starting reference design.
Dhrangdhariya, Priyankkumar, Maiti, Soumyadipta, Rai, Beena
Ducted Fuel Injection Provides Consistently Lower Soot Emissions in Sweep to Full-Load Conditions03-19-01-00017/14/2023
Abstract Earlier studies have proven how ducted fuel injection (DFI) substantially reduces soot for low- and mid-load conditions in heavy-duty engines, without significant adverse effects on other emissions. Nevertheless, no comprehensive DFI study exists showing soot reductions at high- and full-load conditions. This study investigated DFI in a single-cylinder, 1.7-L, optical engine from low- to full-load conditions with a low-net-carbon fuel consisting of 80% renewable diesel and 20% biodiesel. Over the tested load range, DFI reduced engine-out soot by 38.1–63.1% compared to conventional diesel combustion (CDC). This soot reduction occurred without significant detrimental effects on other emission types. Thus, DFI reduced the severity of the soot–NOx tradeoff at all tested conditions. While DFI delivered considerable soot reductions in the present study, previous DFI studies at low- and mid-load conditions delivered larger soot reductions (>90%) compared to CDC operation at the same conditions. Therefore, the DFI configuration used here has been deemed nonoptimal (in terms of parameters such as the injector-spray and piston geometries), and several improvements are recommended for future studies with high-load DFI. These improvements include employing better spray-duct alignment, a deeper piston bowl with a smaller injector umbrella angle, and a fuel injector that opens and closes faster. The study also suggests future research to make DFI ready for commercialization, such as metal-engine tests to ensure desirable DFI performance over an engine’s complete speed/load map. Overall, this study supports the continued development and commercialization of DFI to meet upcoming emissions regulations for heavy-duty vehicles. Specifically, multicylinder engine experiments and CFD simulations should be utilized to optimize the performance and clarify the full potential of DFI.
Buurman, Noad J., Nyrenstedt, Gustav, Mueller, Charles J.
Numerical Validation and Optical Study of Injection of Different Oxymethylene Ether Fuels for Heavy-Duty Application04-17-01-00046/6/2023
{"sub":["1","3"],"content":["A reliable toolchain for the validation and evaluation of numerical spray break-up simulation for the potentially carbon-neutral fuels polyoxymethylene dimethylether (POMDME, or short OME) is developed and presented. The numerical\n investigation is based on three-dimensional computational fluid dynamics (3D-CFD) with the commercial code STAR-CD v2019.1 using a Reynolds-averaged Navier-Stokes (RANS) equations approach. Fuel properties of the representatives\n OME","and OME","are implemented into the software and with that the fuels are investigated numerically."]}{"sub":["1b","3\u20136","1","3","3","3\u20136","1b","1","1b","1","3"],"content":["For validation purposes, optical experimental results in a heated spray chamber with inert nitrogen-pressurized atmosphere are presented. The measurement data are based on Mie scattering of the liquid phase and Schlieren imaging of\n the vapor phase. Solely experimental results are shown for OME","and OME","to assess if the knowledge from the numerical modeling with OME","and OME","can also be transferred to the\n corresponding multicomponent fuels. While the results for a match between OME","and OME","are close, the measurement for OME","exceeds the result of OME","in the liquid penetration\n significantly. This is explained by the molecular structure of the low-volatile additive in OME","based on long-chained polyglycol ethers. For the numerically modeled operating conditions, the fuel injection rate with\n the corresponding fuel is measured. Two atomization and spray break-up approaches are investigated in simulation, based on Reitz-Diwakar (RD) models and a combination using Huh\u2019s atomization and the Kelvin-Helmholtz\n Rayleigh-Taylor (KHRT) spray break-up models. A holistic parameter study in a single operating point with the fuel OME","helps to determine the sensitivities of the models. Adjustments to the spray momentum by a\n variation of the parameter for the nozzle hole diameter are used to get results closely aligned with measurement data. The transfer of the calibrated RD model to a validation study with OME","at different operating\n conditions matches well to measurement with no further adjustments necessary."]}
Gaukel, Kai, Pélerin, Dominik, Dworschak, Patrick, Härtl, Martin, Jaensch, Malte
An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications - QA Test Tatsiana01-17-01-00014/19/2023
Abstract In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfully at a system level by evaluating their range and endurance, but cannot do so at an aerodynamic level when using lift and drag coefficients, CL and CD , as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes an aerodynamic equation of state for lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hovering Ingenuity Mars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10 Bronco. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid mechanics found in fluid-mechanics textbooks.
Burgers, Phillip
Development of a Detailed 3D Finite Element Model for a Lithium-Ion Battery Subject to Abuse Loading2023-01-00074/11/2023
Lithium-ion batteries (LIBs) have been used as the main power source for Electric vehicles (EVs) in recent years. The mechanical behavior of LIBs subject to crush loading is crucial in assessing and improving the impact safety of battery systems and EVs. In this work, a detailed 3D finite element model for a commercial vehicle battery was built, in order to better understand battery failure behavior under various loading conditions. The model included the major components of a prismatic battery jellyroll, i.e., cathodes, anodes, and separators. The models for these components were validated against the corresponding material coupon tests (e.g., tension and compression). Then the components were integrated into the cell level model for simulation of jellyroll loading and damage behavior under three types of compressive indenter loading: (1) Flat-end punch, (2) Hemispherical punch and (3) Round-edge wedge. The comparisons showed reasonable agreement between modeling and experiments. With the validated numerical model, parametric studies were further performed to analyze the effect of separator anisotropy, to highlight its important role in the overall structural response of LIBs.
Engine-in-the-Loop Analysis of the Influence of Manual Gearshift Duration on Vehicle Consumption and Emissions15-16-01-00039/27/2022
Abstract The tightening of emission standards and homologation rules lead car manufacturers to rely on simulation testing in early development phases. Coupling an engine to a testbench controlled by a real-time simulation environment allows flexible, reliable, and reproducible testing for consumption and emission studies. However, interest in this method referred to as engine-in-the-loop (EiL) is relatively recent and few details can be found regarding the simulation environment. Following previous work, this study details a driver model based on the PI structure and augmented with preview and anti-windup. The focus is set on a conventional powertrain with a manual transmission for which the driver must also manage the clutch pedal during gearshift and take-off phases. Extended analysis of vehicle tests allows defining the driver’s behavior during these phases for different profiles. The driver model is then tested in the EiL environment and the impact of the gearshift profile on fuel consumption and pollutant emissions can be assessed. Besides the slight increase in fuel consumption, results show that increasing the gearshift duration degrades the regulation of the richness by the ECU, thus increasing CO engine-out emissions as well as decreasing NOx emissions. Finally, results suggest that a longer gearshift also affects the catalyst efficiency, which results in higher NOx tailpipe emissions.
Gilormini, Thomas, Chessé, Pascal, Tauzia, Xavier, Colin, Hervé
A Novel Approach for the Frequency Shift of a Single Component Eigenmode through Mass Addition in the Context of Brake Squeal Reduction15-16-01-00049/23/2022
Abstract Brake squeal reduces comfort for the vehicle occupants, damages the reputation of the respective manufacturer, and can lead to financial losses due to cost-intensive repair measures. Mode coupling is mainly held responsible for brake squeal today. Two adjacent eigenfrequencies converge and coalesce due to a changing bifurcation parameter. Several approaches have been developed to suppress brake squeal through structural changes. The main objective is to increase the distance of coupling eigenfrequencies. This work proposes a novel approach to structural modifications and sizing optimization aiming for a start at shifting a single component eigenfrequency. Locations suitable for structural changes are derived such that surrounding modes do not significantly change under the modifications. The positions of modifications are determined through a novel sensitivity calculation of the eigenmode to be shifted in frequency. In the present work, the structural changes are carried out on a beam and a brake caliper. Selected eigenfrequencies are shifted while the frequencies of the other eigenmodes are simultaneously fixed. Experimental investigations for the brake caliper validate the numerical findings and the applicability as well as efficiency of the proposed methods.
Deutzer, Marcel, Stender, Merten, Tüpker, Nicolas, Hoffmann, Norbert
Performance Enhancement of Semi-active Continuous Skyhook Control Using Chaotic Map Particle Swarm Optimization-Based Stability Augmentation System15-16-01-00029/16/2022
Abstract Enhancing the performance of a ride-oriented algorithm to provide ride comfort and vehicle stability throughout different terrains is a challenging task. This article aims to improve the performance of the state-of-the-art continuous skyhook algorithm in coupled motion modes with an optimally tuned stability augmentation system (SAS). The tuning process is carried out using a chaotic map-initialized particle swarm optimization (C-PSO) approach with ride comfort and roll stability as a performance index. A large van model built-in CarSim is co-simulated with a C-PSO algorithm and control system designed in MATLAB. To realize the feasibility and effectiveness of the proposed system, a software-in-loop test is conducted on five complex ride terrains with different dominant vehicle body motion modes. The test results are compared against the passive system, four corner continuous skyhook control, and four corner type-1 fuzzy control. The test results confirm the effectiveness of the proposed system in providing better ride comfort, improved roll stability, good road holding, and eliminating the possibility of an untripped rollover. The results indicate a significant performance enhancement of CS-SAS against four corner continuous skyhook in ride road tests with an average root mean square (RMS) heave acceleration reduction of 28.41%. The results also exhibit distinct control effects on vehicle roll by mitigating the RMS-roll angle by an average of 61.52% for stability-based road tests.
Rajasekharan Unnithan, Anand Raj, Subramaniam, Senthilkumar
Study and Application of Gear Micro Modification of Electric Drive System15-16-01-00019/15/2022
Abstract The gear whine in the electric drive system of an electric vehicle is important and remains a challenge in developing novel electric vehicles. A gearbox dynamic model is established, and the effects of modification parameters on the sound pressure level, transmission error, and contact stress of the gear pair are introduced to reduce the gear whine. A multi-objective optimization study of four modification variables under multiple torque conditions is carried out by using transmission error and maximum contact stress as the objective functions. The eclectic programming method is imported to solve the convergence problem of multi-objective optimization. The influence of modification variables on objective functions is studied by establishing an approximate model of the optimal Latin hypercube design. Results show that the application of the multi-objective optimization method combined with the eclectic planning method for the micro modification of the gear can reduce the transmission error of multi-torque conditions, effectively reducing the gear whine noise in multiple torque conditions and improving the contact of the tooth surface.
Chen, Chen, Zhu, Linpei, Liu, Jing, Wei, Dan, Yu, Hao
Reviewers15-15-03-00168/25/2022
Abstract Reviewers
El-Sayed, Mohamed
Experimental Assessment of a Controlled Slippage Magnetorheological Automotive Active Suspension for Ride Comfort10-06-04-00248/23/2022
Active suspensions can alter the dynamic behavior of a vehicle in real time to respond optimally to any given operating scenario. Today’s active suspension technologies such as hydraulics, rotary electromagnetics, and linear electromagnetics do offer performance gains but these gains are outweighed by important disadvantages including high power consumption, low quality of force, and high costs and weights. Controlled slippage magnetorheological (MR) actuators are an emerging alternative actuation technology that is light, compact, power dense, and produces a high-quality force, making it ideal for active suspension applications. This article conducts an in-depth experimental assessment of the potential of MR actuators to increase vehicle ride comfort quality when used as active suspensions. Four high power MR actuators are installed on a BMW 330Ci and tests are performed on a closed road. Results show that with an impedance controller, comfort is increased by 67% at 65 km/h and by 61% at 80 km/h. These results compare favorably with the best-in-class electromagnetic active suspension technologies reported to date and suggest that MR actuators are promising for automotive active suspensions.
Turcotte, Jérôme, East, William, Plante, Jean-Sébastien
Parameters Optimization of a Double Gyroscope Concept for a Two-Wheel Vehicle15-15-02-00094/20/2022
Abstract The concept of making a two-wheeled self-stabilizing vehicle can be a possibility soon. These vehicles use control moment gyroscopes (CMGs) to provide enough torque for the vehicle to prevent it from rolling and falling to the ground. CMGs can be used with different numbers and configurations. In this article, the aim is to offer a design procedure for a double gyroscope system, which can be used for any two-wheel vehicle to be self-stabilized. The procedure is based on using optimization algorithms in reaching the optimum double gyroscope configuration for a certain two-wheel vehicle to reach a zero-degree roll angle in the least time possible, which is the novel part of the procedure. A design procedure for a double gyroscope with the yaw axis as a spinning axis for a two-wheel vehicle is offered. This procedure has been tested for both a small two-wheel robot and a two-wheel enclosed vehicle. The research method started with a presentation of motion equations, followed by a discussion of the use of the PID cascade controller and its tuning process. Also setting up the simulation and finally using the gradient descent method of optimization with both the sequential quadratic programming (SQP) and the interior point algorithms to optimize the simulation results to achieve the optimum design. The simulations were carried out using an initial roll angle of 15°. Before optimization, the small two-wheel robot reached 0° roll angle in nearly 5 seconds at 2000 RPM flywheel spinning velocity and the two-wheel enclosed vehicle reached 0° roll angle in nearly 2.5 seconds at 4000 RPM flywheel spinning velocity. After optimization for the same spinning velocities the small two-wheel robot reached 0° in nearly 2 seconds but the enclosed two-wheel vehicle did not show a significant improvement with the results due to the good performance of the initial design of the vehicle.
Aboelsaoud, Mostafa, Taha, Ahmed Abdelsalam, Mabrouk, Mohamed Yasser, Aboelazm, Mohamed, Elgamal, Hassan
Taxonomy Task Test 515-15-02-00063/22/2022
Taxonomy Task Test 5
Jacob, Sam Jacob, Mrosek, Markus, Othmer, Carsten, Köstler, Harald
Finite Element Analysis on Design Optimized Bevel Gear Pair to Check Its Durability15-15-01-00053/8/2022
Abstract In today’s era, due to increasing energy demands, it is necessary to make vehicles lightweight without affecting their strength. In order to achieve this, the subassemblies of the automobile should be optimized. Optimizing the product not only saves energy consumption but also reduces the material required for manufacturing and increases the overall performance of the product. Taking the same as the base, this article focuses on optimization of a straight bevel gear pair used in automotive differential and performing finite element analysis (FEA) to validate its results. FEA is carried out on the optimized bevel gear to check its durability, and topology optimization is performed on the optimized gear to reduce the mass. Finally, the optimized gear is checked for fatigue. For design optimization, nonlinear multi-objective problem is formulated with a number of teeth and modules as the design parameters. Nondominated Sorting Genetic Algorithm (NSGA)-II algorithm is chosen for optimization. Also multi-body dynamics is performed on the design optimized and topology optimized gear, and the results are compared to understand the effects of weight reduction in the gear with respect to (wrt) vibrations. Design Optimization is accomplished using MATLAB 2018 optimization toolbox, finite element analysis and topology using ANSYS V16.0, and multi-body dynamics using MSC ADAMS 2016.
Kadge, Rushiraj
Real-Time Network Defense of SAE J1939 Address Claim Attacks02-14-03-00268/30/2021
Heavy vehicles are essential for the modern economy, delivering critical food, supplies, and freight throughout the world. Connected heavy vehicles are also driven by embedded computers that utilize internal communication using common standards. However, some implementations of the standards leave an opening for a malicious actor to abuse the system. One such abuse case is a cyber-attack known as the “Address Claim Attack.” Proposed in 2018, this attack uses a single network message to disable all communication to and from a target electronic control unit, which may have a detrimental effect on operating the vehicle. This article demonstrates the viability of the attack and then describes the implementation of a solution to prevent this attack in real time without requiring any intervention from the manufacturer of the target devices. The defense technique uses a bit-banged Controller Area Network (CAN) filter to detect the attack. Once an attack is discovered, the defender induces a CAN protocol error to remove the malicious message from the network. We discuss our results in terms of their applicability for Address Claim Attacks and possible implications for preventing a variety of network-based attacks in real time.
Campo, Matthew Timothy, Mukherjee, Subhojeet, Daily, Jeremy
Applicability of Neck Injury Criteria Critical Intercepts for Human Body Finite Element Models09-09-02-00088/25/2021
The critical intercepts used for the Neck Injury Criterion (Nij) have not been assessed in computational human body models. Under matched-pair conditions, the response of the head-neck complex was compared between the Livermore Software Technology Corporation (LSTC) Hybrid III (HIII) and Global Human Body Models Consortium’s (GHBMC) 50th percentile, detailed male occupant (M50-O) models. The head and neck of the M50-O and HIII were subjected to the dummy performance calibration test procedure for flexion and extension. As a nominal condition, the HIII model met all calibration specifications. Operationalization of the M50-O’s initial position was defined by equivalent head CG location to the HIII and subsequently compared at nominal, ±10%, ±20%, and ±30% of pendulum displacement. Kinematics of the head CG, forces and moments of the upper neck, and changes in neck angle were post processed and compared between the models. The sagittal velocity of the head CG was found to be greater for the M50-O in flexion and for the HIII in extension. Coupled with this trend, greater force and moment exhibited a direct, positive correlation with maximum, sagittal head CG velocity. Correlates of force and moment between the models in both flexion and extension have been derived from the results of this work. As an extension of this finding, modified intercepts of the Nij for application to the M50-O were plotted. These human model-specific critical intercept values may be understood as a consequence of the natural lordosis exhibited by the cervical spine of the M50-O, a feature absent in the HIII. The correlates and conclusions of this work are limited to the range of induced forces and moments, as well as loading rate. Future work will seek to compare the response of the HIII and M50-O models in combined compression-flexion and compression-extension loading.
Johnson, Dale, Devane, Karan, Koya, Bharath, Gayzik, F. Scott
Kinematic and Dynamic Performances of the Hypocycloid Gear Mechanism for Internal Combustion Engine Applications03-15-02-00108/24/2021
Internal combustion (IC) engines incorporating the conventional slider-crank mechanism are subjected to high frictional power losses mainly due to the piston-rod assembly. Due to its simplicity, IC engines have utilized this mechanism almost unchanged since its introduction. This study introduces the hypocycloid gear mechanism (HGM) as an alternative to the conventional slider-crank mechanism for IC engine systems. The HGM provides several advantages that allow for enhancing both the thermal and mechanical efficiencies of IC engines. In this study, the kinematic and dynamic performances of the HGM engine are analyzed in detail. The geometric relations of the HGM are used to derive the kinematic equations that describe the piston motion. These equations are then used to derive the dynamics equations considering gas and inertia forces acting on the HGM. This study also investigates the effect of attaching a flywheel to the HGM engine and suggests a mass-balancing approach for the engine. The results show that the HGM engine can achieve better engine performance in terms of the output torque, and there is a chance to perfectly balance the HGM engine.
ElBahloul, Mostafa A., Aziz, ELsayed S., Chassapis, Constantin
Cavitation Erosion Prediction at Vibrating Walls by Coupling Computational Fluid Dynamics and Multi-body-Dynamic Solutions02-14-03-00218/24/2021
Cavitation erosion caused by high-frequency vibrating walls can appear in the cooling circuit of internal combustion engines along the liners. The vibrations caused by the mechanical forces acting on the crank drive can lead to temporary regions of low pressure in the coolant with local vapor formation, and vapor collapse close to the liner walls leads to erosion damage, which can strongly reduce the lifetime of the entire engine. The experimental investigation of this phenomenon is so time consuming and expensive, which it is usually not feasible during the design phase. Therefore, numerical tools for erosion damage prediction should be preferred. This study presents a numerical workflow for the prediction of cavitation erosion damages by coupling a three-dimensional (3D) Multi-Body-Dynamic (MBD) simulation tool with a 3D Computational Fluid Dynamics (CFD) solver. The multi-body simulation provides the space and time-resolved wall displacements that act as oscillatory boundary conditions for the multiphase flow simulation calculating the vapor formation and the erosion prediction along the liner walls. The CFD model is validated with an acoustic horn test case from the literature. The sub-frequency of vapor formation matches the one measured during experiments. Next, this model setup is applied in a real-case six-cylinder combustion engine. The erosion damage probability of two engine temperature conditions, a warm and a cold engine cooling circuit, is investigated, showing more erosion damage for the latter one. The presented simulation workflow determines a helpful tool during the engine development process since it allows the comparison of different engine designs and operation points with respect to the probability of incurring cavitation erosion damages.
Gomboc, Simon, Cristofaro, Marco, Haramincic, Bruno, Strucl, Jure, Edelbauer, Wilfried
Analyzing Effects of Upperbody on Road Noise of Platform-Sharing Vehicles10-05-04-00348/24/2021
Platform sharing is widely used for reducing time and cost of vehicle development. It has been believed that vehicles that employ the same platform show similar performances of noise and vibration. Recently, however, it is observed that two vehicles that share the same platform present a noticeable difference in road noise. The structural difference between the two vehicles is located only at the upperbody of a Body In White (BIW). In order to investigate the effects of the upperbody on the road noise, several analyses such as (1) input point stiffness, (2) noise transfer function (NTF), and (3) road noise are performed using finite element (FE) models of the vehicles. As a result, it is found that the upperbody affects the NTF of the trimmed body and the road noise, which explains the dissimilarity of the road noise for the two vehicles. A novel method based on equivalent radiated power (ERP) is proposed to assess the upperbody. It is shown that analysis results obtained using the method show good correlation to the NTF of the trimmed body, which determines the road noise. Thus the proposed method can be used to assess an upperbody and predict the road noise of platform-sharing vehicles in the early stage of vehicle development.
Jung, Chulwoo, Lee, Nam Young
48V Exhaust Gas Recirculation Pump: Reducing Carbon Dioxide with High-Efficiency Turbochargers without Increasing Engine-Out NOx02-14-03-00248/23/2021
Regulations limiting GreenHouse Gases (GHG) from Heavy-Duty (HD) commercial vehicles in the United States (US) and European Union will phase in between the 2024 and 2030 model years. These mandates require efficiency improvements at both the engine and vehicle levels, with the most stringent reductions required in the heaviest vehicles used for long-haul applications. At the same time, a 90% reduction in oxides of nitrogen (NOx) will be required as part of new regulations from the California Air Resources Board. Any technologies applied to improve engine efficiency must therefore not come at the expense of increased NOx emissions. Research into advanced engine architectures and components has identified improved turbomachine efficiency as one of the largest potential contributors to engine efficiency improvement. However this comes at the cost of a reduced capability to drive high-pressure Exhaust Gas Recirculation (EGR). This study investigates the combination of a high-efficiency turbocharger and an electric EGR pump to allow improved engine fuel efficiency without the corresponding penalty to engine-out NOx. Results collected on a 13L 2019 model year engine on a dynamometer show the potential for a 3.5% reduction in engine Brake-Specific Fuel Consumption (BSFC) at engine operating conditions representative of highway cruise. Improvements at other engine operating conditions are also possible with careful matching of the turbocharger and EGR pump.
Johnson, Gustav, Bockstanz, Bradford, Bagal, Nilesh, Hopkins, Justin, Hughes, Doug, Playfoot, Ben
Detailed Modeling of Pneumatic Braking in Long Combination Vehicles02-14-03-00208/23/2021
A detailed model for pneumatic S-cam drum brake systems is developed and integrated into a multibody dynamic model for a 33-ft A-double long combination vehicle (LCV). The model, developed in TruckSim®, is used to study the dynamics of LCVs during straight-line braking at various speeds. It includes the response delay in braking that occurs from the time of application to when the brakes are applied at the drum for all axles. Additionally, the model incorporates an accurate characterization of brake torque versus chamber pressure at different speeds, along with the anti-lock brake system (ABS) dynamics, to yield an accurate prediction of the vehicle’s deceleration during braking. The modeling results are compared with test results at speeds ranging from 20 mph to 65 mph on dry pavement. A close match between the model’s prediction and test results is observed. The model is then used to perform a parametric study that evaluates braking distance and time for different pavement coefficients of friction (μp ) at various speeds. The results indicate a distinct nonlinear relationship between μp and braking dynamics. At various μp , stopping time increases linearly with speed, as perhaps expected. Stopping distance, however, increases nonlinearly for a larger μp and linearly for a smaller μp versus speed. At a given speed, stopping time increases nonlinearly with a reduced μp , whereas stopping distance increases relatively linearly with a reduced μp .
Zhang, Zichen, Sun, Nan, Chen, Yang, Ahmadian, Mehdi
Robust Behavioral Cloning for Autonomous Vehicles Using End-to-End Imitation Learning12-04-03-00238/19/2021
In this work, we present a lightweight pipeline for robust behavioral cloning of a human driver using end-to-end imitation learning. The proposed pipeline was employed to train and deploy three distinct driving behavior models onto a simulated vehicle. The training phase comprised of data collection, balancing, augmentation, preprocessing, and training a neural network, following which the trained model was deployed onto the ego vehicle to predict steering commands based on the feed from an onboard camera. A novel coupled control law was formulated to generate longitudinal control commands on the go based on the predicted steering angle and other parameters such as the actual speed of the ego vehicle and the prescribed constraints for speed and steering. We analyzed the computational efficiency of the pipeline and evaluated the robustness of the trained models through exhaustive experimentation during the deployment phase. We also compared our approach against state-of-the-art implementation in order to comment on its validity.
Samak, Tanmay Vilas, Samak, Chinmay Vilas, Kandhasamy, Sivanathan
Oxymethylene Ethers: Quantifying the Effect of Fuel Chain Length and Water Emulsification on Emissions and Combustion in a Heavy-Duty Diesel Engine via Linear Regression Analysis04-14-03-00098/19/2021
Due to the nature of diffusive combustion, diesel engines display a distinct trade-off between nitrogen oxide (NOX) and particulate matter (PM). Since emission regulations become ever stricter, the relevance of dissolving this trade-off increases steadily as it hinders engine development from achieving ultralow emission levels. Seeking new opportunities to approach the problem, the modification of fuel properties has gained much attention. In particular, oxygenated fuels reduce particle emissions drastically, while having little adverse impact on NOX. Similarly, water (H2O) emulsification of diesel is commonly reported to reduce both NOX and PM. Both methods appear very promising, yet only few investigations were conducted in an effort of combing the benefits of the two. With this work, the authors provide a detailed study on combustion and emissions for both neat oxymethylene ethers (OME2-OME5) and an H2O-emulsified OME mixture (OMEmix). By varying injection pressure and fuel properties (i.e., fuel chain length/H2O fraction in OMEmix) separately, the sole impact of altered fuel on the investigated measurands (NOX, carbon dioxide [CO2], combustion speed, cylinder pressure, heat release) could be distinguished and quantified on the basis of a linear regression analysis. It was found that the impact of fuel properties does not interact with varied operating conditions (i.e., rail pressure); thus the impact of altered fuel (chain length, H2O content) onto the measurands is nearly constant. With respect to NOX, the effect of increased fuel chain length (−0.73 g/kWhi with an increase in chain length of one) was found to be approximately twice as pronounced when directly compared with increasing H2O concentration (−0.41 g/kWhi with a 1% increase in H2O share). It was found that CO2 emissions are directly correlating to a rising fuel chain length (approx. +23 g/kWhi with an increase in chain length of one). The latter also affects the combustion process (i.e., combustion speed, max. heat release, max. cylinder pressure) in near-linear correlation. Contrary to the impact of neat OMEn chain length, an additional H2O share in OMEmix barely affected the combustion process.
Dworschak, Patrick, Härtl, Martin, Wachtmeister, Georg
Uncertainty Estimation for Neural Time Series with an Application to Sideslip Angle Estimation12-04-03-00208/19/2021
The automotive industry offers many applications for machine learning (ML), in general, and deep neural networks in particular. However, the real-world deployment of neural networks into safety-critical components remains a challenge as models would need to offer robustness under a wide range of operating conditions. In this work, we focus on uncertainty estimation, which can be used to deliver predictors that fail gracefully, by detecting situations where their predictions are unreliable. Following Gräber et al. [1], we use Recurrent Neural Networks (RNNs) to perform sideslip angle estimation. To perform robust uncertainty estimation, we augment the RNNs with generative models. We demonstrate the advantage of the proposed model architecture over Monte Carlo (MC) dropout [2] on the Revs data set [3].
Ayyad, Ahmed, Prohm, Christopher, Gräber, Torben, Unterreiner, Michael, Hilbert, Marc
Prediction of Vehicle Cabin Occupant Thermal Comfort Using Deep Learning and Computational Fluid Dynamics12-04-03-00228/19/2021
Heating, ventilation, and air-conditioning (HVAC) systems can have a significant impact on the driving range of battery electric vehicles (BEVs). In our previous work, high-fidelity Computational fluid dynamics (CFD) simulations, validated against climatic wind tunnel measurements, were coupled with machine learning (ML) algorithms to predict vehicle occupant thermal comfort for any combination of glazing properties for any window surface, environmental conditions, and HVAC settings (flow rate and discharge air temperature). In the present study, the input feature space was expanded significantly to include climate seats (heated/cooled), heated steering wheel, radiant heating pads, and airflow direction from the air-conditioning (A/C) vents. The modified vehicle cabin CFD model, which included these additional features, was used to generate steady-state training and test data. Feedforward artificial neural networks (ANN) were applied to the simulation data to predict the equivalent homogeneous temperature (EHT) for each occupant. The EHT is a recognized measure of the total heat loss from the human body that can be used to characterize highly nonuniform thermal environments. The prediction performance of the trained deep learning models was evaluated on an unseen test dataset. An ensemble of five neural network models was able to achieve a mean absolute error (MAE) of 2°C or less in predicting the EHT for all occupants in the vehicle, which is acceptable for rapid evaluation of thermal comfort technologies under steady-state conditions.
Warey, Alok, Kaushik, Shailendra, Khalighi, Bahram, Cruse, Michael, Venkatesan, Ganesh
Analysis of the Interaction between Soft Particles and Fuel Filter Media04-14-03-00108/16/2021
The transportation industry is currently in a transition toward the use of zero-emission vehicles; however, reaching it will take a considerable amount of time. In the meantime, a diesel powertrain will remain the workhorse for most heavy-duty transportation. In order to reduce the engine’s environmental impact, biofuels, such as biodiesel, are used as drop-in fuels or fuel blends. The use of drop-in fuels may create challenges for the fuel system since sticky deposits can precipitate and cause injector malfunctioning or premature fuel filter plugging. It has been concluded in the past that these deposits have been caused by soft particles. In this article, soft particles created through the degradation of biodiesel and their effect on filters are studied. The article aims to analyze fuel filters and investigate the materials responsible for soft particle separation. The study includes three pre filters and three main filters that are commercially available truck filters. Different membrane types and membranes with different pore sizes were tested in order to comprehend their potential for fuel filtration. The tests were conducted using a custom-built fuel filter rig, where pressure buildup was measured online. The removal efficiency was assessed by gas chromatography-mass spectrometry (GC-MS) and inductively coupled plasma (ICP). The materials of the filters were examined by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), and thermogravimetric analysis (TGA). The analysis revealed novel results from the interaction of soft particles and different filter media. The filters show similar performance for the commercial fuel filters with respect to soft particle removal and pressure buildup and thus the tendency for fuel filter plugging, where the efficiency for total calcium ion removal was around 40% for pre-filters and 60% for main filters. The material analysis shows that the particles are most likely removed mainly by the cellulose layer of the filter paper, and filters with glass fiber showed higher capacity. In addition, the membrane filters prove to show good potential for soft particle removal, with the highest removal of 72%; however, their use in practice needs to be further evaluated in actual fuel systems.
Csontos, Botond, Bernemyr, Hanna, Pach, Mayte, Hittig, Henrik
Regulated Intake Air Boosting and Engine Downspeeding as a Viable Solution for Performance Improvement and Emission Reduction of a Single-Cylinder Diesel Engine03-15-02-00098/16/2021
The present work proposes a viable approach to develop single-cylinder diesel engines for the future by implementing regulated intake air boosting (RIAB) and engine downspeeding (ED) along with the well-established low compression ratio (LCR) approach. The investigations were conducted in a mass-production light-duty single-cylinder diesel engine initially equipped with a naturally aspirated (NA) intake system. By lowering the compression ratio (CR) and implementing the intake air boosting (IAB) using a belt-driven supercharger, the maximum brake mean effective pressure (BMEP) of the engine could be increased by 50%. More importantly, the improved performance could be achieved without violating the peak firing pressure (PFP) limits. However, a significant penalty was observed in the brake-specific fuel consumption (BSFC) at low-load operating points due to the additional power consumption of the IAB system. Hence, RIAB was implemented to optimize the boost pressure with respect to engine load to simultaneously reduce the BSFC and oxides of nitrogen (NOx) and soot emissions. Further, the increased full-load performance of the engine was leveraged to implement the ED approach that could reduce the operating speeds of the engine by 37.8%. It was observed that the benefits of downspeeding a supercharged engine are significantly high due to the simultaneous reduction of the frictional losses of the base engine and the power consumption of the supercharger. Overall, by combining the above concepts and the proven LCR approach, significant benefits could be achieved in fuel economy and exhaust emissions that are quantified for the regulatory Modified Indian Drive Cycle (MIDC) using a one-dimensional tool. The obtained results show a net reduction of 77.8% and 39.5% in the soot and NOx emissions, respectively. Moreover, a significant benefit of 14.8% could be achieved in the fuel economy. Thus the proposed approach can be used to develop single-cylinder diesel engines for the future to improve vehicle performance and comply with stringent emission regulations.
Vikraman, V., Krishnasamy, Anand, Ramesh, A.
A Unique Application of Gasoline Particulate Filter Pressure Sensing Diagnostics06-14-02-00078/6/2021
Gasoline particulate filters (GPFs) are important aftertreatment components that enable gasoline direct injection (GDI) engines to meet European Union (EU) 6 and China 6 particulate number emissions regulations for nonvolatile particles greater than 23 nm in diameter. GPFs are rapidly becoming an integral part of the modern GDI aftertreatment system. The Active Exhaust Tuning (EXTUN) Valve is a butterfly valve placed in the tailpipe of an exhaust system that can be electronically positioned to control exhaust noise levels (decibels) under various vehicle operating conditions. This device is positioned downstream of the GPF, and variations in the tuning valve position can impact exhaust backpressures, making it difficult to monitor soot/ash accumulation or detect damage/removal of the GPF substrate. The purpose of this work is to present a unique example of subsystem control and diagnostic architecture for an exhaust system combining GPF and EXTUN. In particular, the On-Board Diagnostics (OBD) controls are required to detect a disconnected/plugged downstream hose when combining a differential pressure (dP) sensor and an electronically controlled EXTUN valve in an exhaust system containing a GPF. The regulatory implications related to failing to detect a disconnected/plugged downstream hose are also discussed. Validation data from the control strategy under different operating conditions is reviewed.
Dadam, Sumanth Reddy, Nieuwstadt, Michiel Van, Lehmen, Allen, Ravi, Vinod Kumar, Kumar, Vivek, Bhat, Rohit
Machine Learning-Aided Management of Motorway Facilities Using Single-Vehicle Accident Data09-09-02-00078/6/2021
Management of expressway networks has been mainly focused on defect management without looking at the correlations with accidental risks. This causes unsustainability in expressway infrastructure maintenance since such defects may not be a contributing factor toward public safety. Thus it is necessary to incorporate accidental events for decision-making in infrastructure management. This study has developed a novel approach to machine learning (ML) that incorporates actual primary data from the last 10 years of single-vehicle accidents (SVA) by collisions with motorway facilities, or so-called single-vehicle collisions with fixed objects. The ML is firstly aimed at identifying the influential factors of SVA in relation to finding effective countermeasures for accidents by integrating the correlation analysis, multiple regression analysis, and ML techniques. The study reveals that wet pavement conditions have a significant effect on SVA. The results show that improvement of the skid resistance is the most effective method to reduce SVA when the average vehicle speed (AVS) is less than 60 km/h. At the locations with gentle curve radii, ML indicates that it is crucial to redesign the speed-through management. Interestingly, the real data over 10 years indicate no relationship between equivalent single axle load (ESAL) and skid resistance, although many other studies have demonstrated the inverse relationship. In this study, the novel ML mean demonstrates excellent capability in providing suitable countermeasures for a reduction of SVA under a variety of uncertain and road quantitative aspects. The ML-based mitigation policies can also be applicable to other motorways and can contribute to their road safety, underpinning sustainable transport systems.
Kaewunruen, Sakdirat, Alawad, Hamad, Omura, Takashi, Saito, Motoyasu
Study on the Influence of Mass Flow Rate over a National Advisory Committee for Aeronautics 6321 Airfoil Using Improved Blowing and Suction System for Effective Boundary Layer Control01-14-02-00118/6/2021
The numerical analysis of the three-dimensional (3D) flow over a National Advisory Committee for Aeronautics (NACA) 6321 airfoil to evaluate the mass flow rate by using a novel method Improved Blowing and Suction System (IBSS) to control the boundary layer is presented in this study. Analysis is performed based on 3D Reynolds-Averaged Navier-Stokes (RANS) equation with a K-omega SST solver. The aerodynamic performance of the NACA 6321 is analyzed at a Mach number of 0.10 with three different mass flow rates, namely, 0.08 kg/s, 0.10 kg/s, and 0.12 kg/s. From the study, it is seen that when the mass flow rate decreased, the aerodynamics performance also reduced, and the aerodynamic performance improved with the increase in mass flow rate. Results also show that a mass flow rate of 0.10 kg/s improved the stalling angle of attack (AoA) by 60% and coefficient of lift (CL) by 50%, enabling optimum efficiency of the aircraft wing in all aspects compared to the baseline airfoil model. The mass flow for optimum efficiency is computed based on the velocity at the separation point on the airfoil.
Karuppiah, Balaji, Wessley, Jims John
Knock: A Century of Research03-15-01-00047/28/2021
Knock is one of the main limitations on increasing spark-ignition (SI) engine efficiency. This has been known for at least 100 years, and it is still the case today. Knock occurs when conditions ahead of the flame front in an SI engine result in one or more autoignition events in the end gas. The autoignition reaction rate is typically much higher than that of the flame-front propagation. This may lead to the creation of pressure waves in the combustion chamber and, hence, an undesirable noise that gives knock its name. The resulting increased mechanical and thermal loading on engine components may eventually lead to engine failure. Reducing the compression ratio lowers end-gas temperatures and pressures, reducing end-gas reactivity and, hence, mitigating knock. However, this has a detrimental effect on engine efficiency. Automotive companies must significantly reduce their fleet carbon dioxide (CO2) values in the coming years to meet targets resulting from the 2015 Paris Agreement. One path towards meeting these is through partial or full electrification of the powertrain. However, the vast majority of automobiles in the near future will still feature a gasoline-fueled SI engine; hence, improvements in combustion engine efficiency remain fundamental. As knock has been a key limitation for so long, there is a huge amount of literature on the subject. A number of reviews on knock have already been published, including in recent years. These generally concentrate on current understanding and status. The present work, in contrast, aims to track the progress of research on knock from the 1920s right through to the present day. It is hoped that this can be a useful reference for new and existing researchers of the subject and give further weight to occasionally neglected historical activity, which can still provide important insights today.
Corrigan, Daire James, Fontanesi, Stefano
Experimental Analysis of the Influence of Body Stiffness on Dynamic Suspension Kinematics and Compliance Characteristics and Dynamic Body Behavior10-05-04-00327/14/2021
Many disciplines of the current vehicle development process are still based on subjective scoring of prototypes, especially in the field of vehicle dynamics. To further reduce the need for hardware and to discover possible weaknesses early in the development process and therefore reduce costs, suitable simulative methods are required. The influence of body and chassis stiffness on vehicle dynamics is not fully understood and requires further research to implement reliable simulative methods. The development of methods requires an understanding and objective depiction of the physical chain. The influences of stiffening beams at the front of a vehicle on the static and dynamic response of wheels and body are observed by using static and dynamic suspension kinematics and a compliance test rig setup. This response is assessed by acceleration sensors, strain gauges, and optical measurement of wheel positions. Static load cases show that minor differences are caused by varying the vehicle’s stiffness. In the dynamic case, greater differences can be observed, especially by the acceleration sensors applied to the body. Dynamic assessment of the body and chassis stiffness can support future development of light and robust bodies and chassis while allowing for cost reduction by decreasing the need for hardware. Further research and objectification will lead to simulative models that can replace prototypes.
Derrix, Daniel, Deubel, Clemens, Kubenz, Jan, Prokop, Günther
Comparisons of Cloud In Situ Microphysical Properties of Deep Convective Clouds to Appendix D/P Using Data from the High-Altitude Ice Crystals-High Ice Water Content and High Ice Water Content-RADAR I Flight Campaigns01-14-02-00074/19/2021
In situ cloud data from three international flight campaigns are compared to the Federal Aviation Administration (FAA) Title 14 Code of Federal Regulations Part 33 Appendix D mixed-phase/glaciated environmental envelope and the corresponding identical European Union Aviation Safety Agency (EASA) CS-25 Appendix P envelope. The appendices consist of a temperature-altitude envelope, a 99th percentile total water content (TWC) envelope at the 17.4 Nm distance scale, a distance factor for estimation at other distance scales, ice crystal median mass diameter (MMD), and recommended liquid water content (LWC) levels in mixed-phase icing conditions. The data were collected during 54 flights out of one subtropical and two tropical locations, with 472 runs from about 17,000 ft to 39,000 ft in approximately 115 clouds. The campaigns provide about 29,600 Nm of in situ data in deep convection over four targeted temperature intervals: −10°C, −30°C, −40°C, and −50°C, all ±5°C. The dataset is a modern and unique documentation of the deep convective cloud ice crystal icing (ICI) environment, and the results described in this article will contribute to regulatory and industry assessment of Appendices D and P.
Strapp, John Walter, Schwarzenboeck, Alfons, Bedka, Kristopher, Bond, Tom, Calmels, Alice, Delanoe, Julien, Dezitter, Fabien, Grzych, Matthew, Harrah, Steven, Korolev, Alexei, Leroy, Delphine, Lilie, Lyle, Mason, Jeanne, Potts, Rodney, Protat, Alain, Ratvasky, Thomas, Riley,, James T., Wolde, Mengistu
Developing an Experimental Setup for Real-Time Road Surface Identification Using Intelligent Tires10-05-03-00244/7/2021
Road surface characteristics directly influence vehicle safety and performance, and its knowledge can be instrumental to road transportation system safety. This work focuses on the development of a test setup, which was utilized for real-time implementation of a road surface identification algorithm based on the acceleration response of an intelligent tire. Analysis of frequency domain data was used to leverage the tire-road contact information being relayed through the acceleration data. A signal processing algorithm was developed to separate each tire revolution, analyze it in real-time, and convert it to the frequency domain in real-time. In the end, the performance of the setup was validated with results from the literature, and the distinguishing signature possessed by each surface was used to categorize different terrains into the respective surface categories (Dry Asphalt, Wet Asphalt, Concrete) in real-time.
Gupta, Utkarsh, Nouri, Arash, Subramanian, Chidambaram, Taheri, Saied, Kim, Min-Tae, Lee, Hojong
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