bluuebunny/crossref_metadata_2025 huggingface dataset:
Motorcycle Chassis Design Utilizing Multi-Material Topology Optimization
Authors: Kashanian Kiarash , Shah Vishrut , Pamwar Manish , Sangha Balbir , Kim Il Yong
Published: April 2020

Evolving fuel efficiency and emissions standards, along with consumer demand for performance, are strong pressures for light-weighting of performance oriented motorcycles. The field of topology optimization (TO), with the extension of multi-material topology optimization (MMTO) provide manufacturers with advanced structural light-weighting methodology. TO methodology has been adopted in many industries, including automotive where light-weighting assists in meeting efficiency regulations. The development of process specific manufacturing constraints within MMTO is a critical step in increasing adoption within industries dealing with manufacturing cost restrictions. This capability can decrease design complexity, lowering manufacturing costs of optimization solutions.

A conventional all-aluminum perimeter style motorcycle chassis is analyzed to develop baseline compliance (total strain energy) metrics. An MMTO design space is created and optimized with steel and aluminum, such that results match the baseline design weight. This formulation demonstrates increased structural efficiency through stiffer structures at equivalent weight. Results are generated with standard MMTO, symmetry, and extrusion constraints to demonstrate utility of these manufacturing constraints. Material ratios are used to enforce lower cost material distribution selections.

The usage of MMTO with manufacturing and material ratio constraints has resulted in up to 60.4% reduction in structural compliance of designs, and a multitude of lower cost alternative designs. The usage of symmetry constraints provides effectively identical results to standard MMTO, with a computational time reduction of 29%. Extrusion constraints demonstrate decreased manufacturing difficulty with a computational time reduction of 52% and structural performance penalty of 58.6% from the lowest compliance MMTO result. The enforcement of steel has demonstrated a decrease in structural performance (increase in compliance) and material costs, with varying degrees depending on manufacturing constraints and enforcement limits. The MMTO based designs provide a range of solutions to designers, which can be selected based on the importance of structural efficiency, manufacturing difficulty, and material costs.
Biofidelity of THOR 5th Percentile Female ATD in Ankle Eversion and Inversion
Authors: Kulkarni Shubham , Roberts Carolyn , Foltz Patrick , Forman Jason
Published: April 2020

Females have higher frequency and risk of foot and ankle injuries in motor vehicle collisions than similar-sized males. Therefore, lower extremity biofidelity and accurate injury prediction of female ATDs is critical. This paper aims to compare the THOR 5th percentile female (THOR-05F) anthropomorphic test device (ATD) response with male and female PMHS data of various sizes under ankle inversion and eversion. The THOR-05F lower extremity was subjected to dynamic inversion and eversion ankle loading with a constant 2000N axial force applied through the tibia. Twelve THOR-05F tests (3 inversion and 3 eversion on both, left and right legs) were performed with boundary conditions consistent with previous post-mortem human subject (PMHS) lower extremity tests. The biofidelity of THOR-05F ankle stiffness was evaluated via comparison of measured and equal-stress equal-velocity scaled data (using mass-based scale factors) from previous PMHS datasets with mid-size males, small females and larger females. THOR-05F ankle moment-angle response falls within the range of previous mid-sized male and larger female PMHS test data for eversion, when scaled to a small female. However, when compared to PMHS response measured on small female subjects, the THOR-05F response was less stiff in both inversion and eversion. The THOR-05F moments were 65% and 90% less stiff in eversion and inversion respectively, when compared to the average of the measured small female PMHS dataset at 25° ankle rotation. Because ATD stiffness differs from measured PMHS ankle stiffness, care should be taken when applying PMHS-based injury risk functions (IRF) to the THOR-05F ankle.
Deep Learning-Based Queue-Aware Eco-Approach and Departure System for Plug-In Hybrid Electric Buses at Signalized Intersections: A Simulation Study
Authors: Ye Fei , Hao Peng , Wu Guoyuan , Esaid Danial , Boriboonsomsin Kanok , Gao Zhiming , LaClair Tim , Barth Matthew
Published: April 2020

Eco-Approach and Departure (EAD) has been considered as a promising eco-driving strategy for vehicles traveling in an urban environment, where information such as signal phase and timing (SPaT) and geometric intersection description is well utilized to guide vehicles passing through intersections in the most energy-efficient manner. Previous studies formulated the optimal trajectory planning problem as finding the shortest path on a graphical model. While this method is effective in terms of energy saving, its computation efficiency can be further enhanced by adopting machine learning techniques. In this paper, we propose an innovative deep learning-based queue-aware eco-approach and departure (DLQ-EAD) system for a plug-in hybrid electric bus (PHEB), which is able to provide an online optimal trajectory for the vehicle considering both the downstream traffic condition (i.e. traffic lights, queues) and the vehicle powertrain efficiency. Based on optimal solutions obtained from the graph-based trajectory planning algorithm (GTPA), a deep neural network (DNN) is developed to learn the optimal vehicle speed for the next time step given its current state. It is demonstrated that the trained DNN can provide energy-efficient trajectories with high computational efficiency and high flexibility adopting to dynamic changes in the surrounding environment. To address the impact of downstream traffic, a queue prediction model is further developed using data from radars and connected vehicles (CVs), as well as signal timing data from SPaT messages. A comprehensive simulation study in the microscopic traffic modeling software PTV VISSIM shows that the proposed DLQ-EAD can achieve 18.7%-24.0% energy efficiency improvements for a single PHEB on various traffic congestion levels. The proposed queue prediction model can be of practical significance even at low penetration rates of CVs. Specifically, additional energy savings of 2.0%-8.2% can be further achieved with 20% vehicles in the network.
Experimental Characterization of Piezoelectric Transducers for Automotive Composite Structural Health Monitoring
Authors: Carello Massimiliana , Ferraris Alessandro , Airale Andrea Giancarlo , Messana Alessandro , Sisca Lorenzo , de Carvalho Pinheiro Henrique , Reitano Simone
Published: April 2020

Composite materials are a natural choice for automotive applications where mechanical performance and lightweight are required. Nevertheless, attention should be directed to the defects into the material. This paper presents the building up of a Structural Health Monitoring system based on a piezoelectric transducers network: a continuous data system acquisition has been carried out in order to detect the presence of faults inside the analyzed structure. A piezoceramic patch has been coupled to a host structure in composite, to characterize the acquisition and the transmission of a wave signal on the material. The importance of this advanced technology research and the positive results obtained in the case study constitute the starting point for future application of piezoelectric-based Structural Health Monitoring systems over real industrial components.
Numerical Investigation of the Influence of Oil Dilution on the Ability to Initiate a Pre-Ignition Combustion
Authors: Zöbinger Norbert , Lauer Thomas
Published: April 2020

Although the root-cause of the initial pre-ignition is not yet proven, there is a general agreement throughout the literature that it is very likely a 2-phase particle or droplet induced phenomenon. In the case of a droplet induced mechanism there are still uncertainties regarding the detached droplet size, velocity and composition. Former research work suggests that heavy wall wetting during injection is increasing the PI-frequency in WOT operation points. Due to the oil dilution the viscosity and the surface tension are reduced, which enhances the likelihood of detachment.

The present work is therefore investigating the influence of the oil dilution on the droplet evaporation and the PI-tendency. According to previous work performed at the research group, there is an influence of the radical ketohydroperoxide that has its origin in incomplete oil combustion on the pre-ignition probability of an engine cycle. This underlines the role of oil combustion chemistry and the oil mass fraction in detached droplets.

In order to characterize the droplet evaporation a multicomponent surrogate model was chosen. The selection of the species is based on the distillation curves and the basic chemical composition using a detailed distillation model. In order to capture mixture effects, the vapor-liquid-equilibrium incorporates activity coefficients calculated by the UNIFAC method. The investigated lubricant oil is modelled as a mixture of four n-alkanes based on a GC-analysis. This established model shows a good agreement with the measurement data.

The fluid surrogates are transferred to a CFD-code to predict the evaporation behavior of different oil-fuel mixtures under engine-like conditions. Different release timings during a compression stroke are investigated. The compression is modelled through a time-dependent change of the ambient gas pressure and temperature. Furthermore, a sensitivity analysis of the boundary conditions (DDrop, TDrop) was performed. It can be shown that a 250 μm droplet can lead to an ignitable condition up to a fuel share of 25 %.
Experimental Investigation of Automotive Vehicle Transient Aerodynamics with a Reduced-Scale Moving-Model Crosswind Facility
Authors: Bell James R. , Wilhelmi Henning , Heine Daniela , Jessing Christoph , Wagner Andreas , Wiedemann Jochen , Ehrenfried Klaus , Wagner Claus
Published: April 2020

Automotive vehicles operate in complex, transient aerodynamic conditions that can potentially influence their operational efficiency, performance and safety. A moving-model facility combined with a wind-tunnel is an experimental methodology that can be utilized to model some of these transient aerodynamic conditions. This experimental methodology is an alternative to wind-tunnel experiments with additional crosswind generators or actively yawing models, and has the added benefit of modelling the correct relative motion between the vehicle and the ground/infrastructure. Experiments using a VW Golf 7 were performed with a 1:10 scale model at the moving-model facility at DLR, Göttingen and a full-scale, operational vehicle at the BMW Ascheim side-wind facility. Successful functionality of the newly developed automotive-vehicle configuration of the moving-model facility - including the side wind-tunnel operation, rotating wheels in contact with the ground, and data-acquisition on-board the moving model - was achieved. Direct comparison of transient pressure at 24 locations across the front and rear bumpers and over the centerline of the vehicles show relatively good agreement between the two methodologies; establishing the moving-model facility as a viable reduced-scale methodology for investigating transient aerodynamics of automotive vehicles. Analysis of the time-resolved pressure measurements provides insight into the sensitivity of the surface pressure to transient crosswind; with indications that transient characteristics can only be captured with transient modelling of the crosswind-vehicle interaction.
A Study on the Effect of Debris Location on a Double Element Wing in Ground Effect
Authors: Marsh Tom , Hodgson Graham , Garmory Andrew , Patel Dipesh
Published: April 2020

Multi-element front wings are essential in numerous motorsport series, such as Formula 1, for the generation of downforce and control of the onset flows to other surfaces and cooling systems. Rubber tyre debris from the soft compounds used in such series can become attached to the wing, reducing downforce, increasing drag and altering the wake characteristics of the wing. This work studies, through force balance and Particle Image Velocimetry (PIV) measurements, the effect a piece of debris has on an inverted double element wing in ground effect. The debris is modelled using a hard-setting putty and is located at different span and chord-wise positions around the wing. The sensitivity to location is studied and the effect on the wake analysed using PIV measurements. The largest effect on downforce was observed when the debris was located on the underside of the wing towards the endplates. The wake was most effected when the debris was located closest to the gap, generating a large fluctuating wake with a significantly different path to the baseline case.
Investigation of the Effectiveness of a Passive Device for Soiling Mitigation for Vehicle Side-Cameras
Authors: Collings William , Pao Wing Yi , Agelin-chaab Martin
Published: April 2020

The development of modern autonomous automotive technology depends heavily on the reliable performance of external sensors that are vulnerable to soiling. Existing active cleaning devices, such as washers and wipers, are relatively complex and expensive. Furthermore, little research has been done on alternative soiling mitigation strategies and devices for sensors. With the emerging trend of replacing side-mirrors with camera monitor systems, it is important for such systems to stay clean in adverse weather in order to provide critical navigation information. To meet this need, a passive aerodynamics-based cleaning device was investigated. A converging vent device was integrated into the side-camera housing and the subsequent degree of soiling was estimated at a wind speed of 20 m/s (72 km/h), representing urban and suburban driving speeds. The vent outlet height and outlet jet angle of the vent device were varied and the variants were compared to the non-vented reference model. The degree of soiling was evaluated experimentally and computationally. The variants were 3D-printed and sprayed with water in wind tunnel tests, where the degree of soiling was quantified by water droplet counts. Numerical simulation was also performed using ANSYS® Fluent to visualize the airflow patterns. The results from wind tunnel tests and CFD suggest that the vent device is effective in reducing soiling for up to 94%. This investigation demonstrated that the outlet geometry of a passive vent device significantly affects the deposition aerodynamics and type of soiling on a sensor and provides insight for further design and development of such devices.
Prediction of Fuel Maps in Variable Valve Timing Spark Ignited Gasoline Engines Using Kriging Metamodels
Authors: Tafreshi Ali , Mourelatos Zissimos
Published: April 2020

Creating a fuel map for simulation of an engine with Variable Valve Actuation (VVA) can be computationally demanding. Design of Experiments (DOE) and metamodeling is one way to address this issue. In this paper, we introduce a sequential process to generate an engine fuel map using Kriging metamodels which account for different engine characteristics such as load and fuel consumption at different operating conditions. The generated map predicts engine output parameters such as fuel rate and load. We first create metamodels to accurately predict the Brake Mean Effective Pressure (BMEP), fuel rate, Residual Gas Fraction (RGF) and CA50 (Crank Angle for 50% Heat Release after top dead center). The last two quantities are used to ensure acceptable combustion. The metamodels are created sequentially to ensure acceptable accuracy is achieved with a small number of simulations. Two optimization problems are then solved using the developed metamodels, for full load and part load conditions, respectively. We demonstrate that the estimated fuel map is of high accuracy compared to the actual map. The map is obtained with about one tenth of the number of engine simulations for a full factorial design, leading to much faster predictions.
A Virtual Driveline Concept to Maximize Mobility Performance of Autonomous Electric Vehicles
Authors: Vantsevich Vladimir , Gorsich David , Paldan Jesse R. , Letherwood Michael
Published: April 2020

In-wheel electric motors open up new prospects to radically enhance the mobility of autonomous electric vehicles with four or more driving wheels. The flexibility and agility of delivering torque individually to each wheel can allow significant mobility improvements, agile maneuvers, maintaining stability, and increased energy efficiency. However, the fact that individual wheels are not connected mechanically by a driveline system does not mean their drives do not impact each other. With individual torques, the wheels will have different longitudinal forces and tire slippages. Thus, the absence of driveline systems physically connecting the wheels requires new approaches to coordinate torque distribution. This paper solves two technical problems. First, a virtual driveline system (VDS) is proposed to emulate a mechanical driveline system virtually connecting the e-motor driveshafts, providing coordinated driving wheel torque management. The VDS simulates power split between driving wheels. Conceptually, VDS is founded on generalized tire and vehicle parameters. Generalized slippages are utilized to determine virtual gear ratios from a virtual transfer case to each wheel. The virtual gear ratios serve as signals to the electric motors. Secondly, a new velocity-based mobility performance index is used as the ratio of the actual velocity of a vehicle, with individual wheel management, to the theoretical velocity of the same vehicle equipped with a mechanical driveline without controllable gear ratios. Using the index as the objective function, a maximization problem of vehicle mobility is formulated and solved. Optimal virtual gear ratios are determined for maximal mobility in a given terrain condition. Simulations of a 4x4 tactical vehicle in stochastic soil conditions demonstrated a 17% increase in mean values of the velocity-based mobility performance index when the vehicle is electrically driven by the optimal virtual gear ratios as compared to the mechanical driveline system with non-controlled differentials.
The Study on Fatigue Bench Test and Durability Evaluation of a Light Truck Cab
Authors: Gao Yunkai , Yuan Ze , Duan Yuexing
Published: April 2020

The cab is an essential part of a light truck, and its fatigue durability performance plays an important role in the design and development stage. Accelerated fatigue bench test has been widely applied to product development of carmakers for its low cost and short development cycle. However, in reality, interference exists generally in torsional conditions for the light truck cab when tested on the 4-post vehicle road simulation system. To solve this problem and minimize the lateral force applied on the hydraulic cylinders, the direction and size combinations of displacement release about front and rear suspensions were discussed based on multi-body dynamics simulation and fixture design theory in this paper. Through comparative study, the optimum design and layout scheme of fixtures was determined to conduct the next test procedure. The weak positions of the light truck cab were firstly predicted by utilizing finite element method (FEM) and fatigue analysis theory. Then, the strain gage, which was used for monitoring the stress, was pasted on one weak position analyzed by simulation. According to the observation of stress using the LMS Test.Lab, a modified standardized programmed load spectrum was proposed for fatigue bench test. The test of the cab was conducted, and the design weaknesses of the light truck cab were checked out. Finally, required design modifications were applied to the cab. Bench test results demonstrated that compared with the initial cab, fatigue durability performance of the modified cab has improved.
Aging of a Multi-Hole Diesel Injector and Its Effect on the Rate of Injection
Authors: Payri Raul , Salvador Francisco Javier , Gimeno Jaime , Montiel Tomas
Published: April 2020

In order to comply with the increasingly restrictive limits of emissions and fuel consumption, researches are focusing on improving the efficiency of combustion engines. In this area, the aging of the injector and its effect on the injection development is not entirely analyzed. In this work, the rate of injection of a diesel injector at different stages of its lifetime is analyzed. To this end, a multi-hole piezoelectric injector was employed, comparing the injection rate measured at the beginning of its lifetime to the rate provided by the injector after aging, maintaining the same boundary conditions in both measurements. Injection pressures up to 200 MPa were used throughout the experiments. The results showed that the steady-state rate of injection was lower after the injector aged. Furthermore, the injector took a longer time to close the needle and end the injection, in comparison with the measurements done at earlier stages of its lifetime. To explain this phenomenon, measurements of momentum flux for each injector hole were done, and results showed that two holes were partially obstructed. Thus, the presence of coking in the nozzle of the injector was considered as the cause of the differences between stages seen in the rate of injection. In this sense, a reduction of the effective outlet holes area due to deposits would restrict the flow rate. Moreover, the pressure in the nozzle due to the contained fuel is extended, leading to a longer time required by the needle to descend and end the injection. Then, aging of the injector was attributed to deposits in the nozzle holes. This phenomenon could result in an inhomogeneous spray distribution, which should be taken into account when designing the combustion process.
Accelerated Sizing of a Power Split Electrified Powertrain
Authors: Anselma Pier Giuseppe , Biswas Atriya , Bruck Lucas , Amirfarhangi Bonab Saeed , Lempert Adam , Roeleveld Joel , Madireddy Krishna , Rane Omkar , Wasacz Bryon , Belingardi Giovanni , Emadi Ali
Published: April 2020

Component sizing generally represents a demanding and time-consuming task in the development process of electrified powertrains. A couple of processes are available in literature for sizing the hybrid electric vehicle (HEV) components. These processes employ either time-consuming global optimization techniques like dynamic programming (DP) or near-optimal techniques that require iterative and uncertain tuning of evaluation parameters like the Pontryagin’s minimum principle (PMP). Recently, a novel near-optimal technique has been devised for rapidly predicting the optimal fuel economy benchmark of design options for electrified powertrains. This method, named slope-weighted energy-based rapid control analysis (SERCA), has been demonstrated producing results comparable to DP, while limiting the associated computational time by near two orders of magnitude. In this paper, sizing parameters for a power split electrified powertrain are considered that include the internal combustion engine size, the two electric motor/generator sizes, the transmission ratios, and the final drive ratio. The SERCA approach is adopted to rapidly evaluate the fuel economy capabilities of each sizing option in various driving missions considering both type-approval drive cycles and real-world driving profiles. While screening out for optimal sizing options, the implemented methodology includes drivability criteria along with fuel economy potential. Obtained results will demonstrate the agility of the developed sizing tool in identifying optimal sizing options compared to state-of-the-art sizing tools for electrified powertrains.
Development of Logistic Regression Models to Classify Seat Fit
Authors: Lee Baekhee , Jung Kihyo , Park Jangwoon
Published: April 2020

The digital evaluation process of vehicle-seat dimensions is an efficient and cost-effective way to achieve better seating comfort and proper fit. The present study is intended to quantify the statistical relationships between seat dimensions (e.g., insert width and bolster height defined at SAE J2732) and subjective seat fit (e.g., too tight, right fit, or too wide). Subjective fit evaluations for 45 different vehicle seats and the corresponding vehicle seat dimensions at various cross-sectional planes were collected by seat engineers (experts). The best subset logistic regression analyses were applied to quantify the relationships between the collected expert evaluations and seat dimensions at each cross-sectional plane. As a result, significant seat dimensions on the seat fit were identified and their statistical relationships were quantified as regression coefficients. The developed logistic models showed 80% - 90% as overall classification accuracy, and around 80% accuracy with five-fold cross-validations. The developed models would be particularly useful to identify optimal seat dimensions providing proper fit, reduce development cost for an automobile seat, and increase work efficiency in the digital evaluation process of an automobile seat.
Motorcycle Instrument Clusters for Collision Reconstruction
Authors: Goddard Christopher H.
Published: April 2020

The behaviour of the instrument cluster of passenger cars during a collision is reasonably well understood, following a number of studies over the past decade. However, one of the frequent questions asked is if motorcycle instruments can be considered in the same way as passenger cars. Motorcycle instruments work in the same way as passenger car instruments. The older models use a Bowden cable to drive a spinning magnetic cup, which drags an instrument needle against a hair spring. Newer models (typically post 2000) use a stepper motor which requires power to drive the needle to any indicated position, including returning it to zero. Hence if power to the instrument is lost as a result of a collision, there is no electrical power to the motor to move the needle, and it should be left at its last position before the power was lost. However, the accelerations experienced by a motorcycle instrument during a collision are significantly different from those of an instrument cluster housed within the dash of a passenger car. Over the past few years a number of crash tests involving motorcycles have been carried out in the USA and UK and the behaviour of the instruments were analysed to see how they perform at holding any residual reading.
Super High Transfer Efficiency Application for Body Coating
Authors: Murai Yuki , Kondo Takahito , Tani Shinji , Murata Wataru
Published: April 2020

In order to achieve the Toyota Environmental Challenge of 2050 (zero CO2 emissions), we have developed an innovative coating system that achieves more than 95% transfer efficiency. In order to reduce paint loss in the painting process, it is necessary to eliminate overdust and bounce dust. The most important point is how to spray (atomization, particle flight, adhesion) without shaping air. We have developed a “super high transfer efficiency system” that eliminates the need for shaping air. We continue to challenge the development of innovative technologies to view the paint shop as clean and eco-friendly environment.
Optimization of an Asymmetric Twin Scroll Volute Turbine under Pulsating Engine Boundary Conditions
Authors: Palenschat Torsten , Wahl Peter , Nakov Galin , Hoffmann Kai , Martinez-Botas Ricardo
Published: April 2020

Future CO2 emission legislation requires the internal combustion engine to become more efficient than ever. Of great importance is the boosting system enabling down-sizing and down-speeding. However, the thermodynamic coupling of a reciprocating internal combustion engine and a turbocharger poses a great challenge to the turbine as pulsating admission conditions are imposed onto the turbocharger turbine. This paper presents a novel approach to a turbocharger turbine development process and outlines this process using the example of an asymmetric twin scroll turbocharger applied to a heavy duty truck engine application. In a first step, relevant operating points are defined taking into account fuel consumption on reference routes for the target application. These operation points are transferred into transient boundary conditions imposed on the turbine. These pulsating admission conditions to the turbocharger turbine are analyzed and subsequently discretized using the method of quasi-steadiness to avoid numerically very expensive unsteady CFD simulations. Following, an automated in-house developed workflow based on a parameterized model of the entire turbine stage is introduced and described. The parameterization is based on design parameters linked to aerodynamic properties, hence it is not limited to one specific geometry but rather able to represent a large variety of designs with comparatively few input parameters. Concluding, a meta-model based multi-disciplinary and multi-objective numerical optimization is performed to obtain the best geometry possible. The optimization objectives are linked to a perfect turbine-compressor matching with an existing benchmark compressor stage and regards to the engine’s air fuel ratio and exhaust gas recirculation requirements. The entire optimization is based on numerical methods, that is, a CFD study. However, the numerical models used throughout the paper are validated against experimental data to ensure the quality and accuracy of the predictions regarding its behavior in an experimental setup.
Fuel Tank Dynamic Strain Measurement Using Computer Vision Analysis
Authors: Fleming Mark , Krishnaswami Ram , Nakamoto Kunihiro
Published: April 2020

Stress and strain measurement of high density polyethylene (HDPE) fuel tanks under dynamic loading is challenging. Motion tracking combined with computer vision was employed to evaluate the strain in an HDPE fuel tank being dynamically loaded with a crash pulse. Traditional testing methods such as strain gages are limited to the small strain elastic region and HDPE testing may exceed the range of the strain gage. In addition, strain gages are limited to a localized area and are not able to measure the deformation and strain across a discontinuity such as a pinch seam. Other methods such as shape tape may not have the response time needed for a dynamic event. Motion tracking data analysis was performed by tracking the motion of specified points on a fuel tank during a dynamic test. An HDPE fuel tank was mounted to a vehicle section and a sled test was performed using a Seattle sled to simulate a high deltaV crash. Multiple target markers were placed on the fuel tank. The motion of these markers was captured using high speed video cameras. The high speed videos were processed using the OpenCV computer vision library. Using OpenCV, the high speed videos were imported, and the position of the central location of each target marker was extracted frame by frame from the high speed videos. Once the position was known, the strain was computed using the change in relative position between two marker positions. Results of the testing showed that the acceleration-induced strain is low, generally less than the material yield strain. It was noted that reliable and accurate results require that the camera be placed normal to, or at a shallow angle to, the points being tracked. In addition, curved surfaces lead to limited fidelity of strain data due to the varying focal length of the points being tracked and measurement increased sensitivity. This method is similar to a “typical” tensile test in which displacement is tracked between two pre-established points on a sample. As such, the methodology was replicated on a tensile specimen to validate the methodology.
Durability Study of Automotive Additive Manufactured Specimens
Authors: Zareanshahraki Forough , Davenport Amelia , Cramer Neil , Seubert Christopher , Lee Ellen , Cassoli Matthew
Published: April 2020

The long-term weathering behavior of three different 3D printable, non-stabilized, UV cure resin formulations (A and B with thiol-ene base, and C with acrylate chemistry) was studied using tensile testing, nano-indentation, and photoacoustic infrared (FTIR-PAS) spectroscopy. To this end, type I tensile bars were printed from each resin system using a 3D printer, and were post UV-cured under a broad spectrum source. Systems A and C showed a similar trend after weathering. They first experienced an increase in modulus and tensile strength, due to additional crosslinking of the residual unreacted species. This increase in mechanical properties was followed by a drop in modulus, tensile strength, and percent elongation, due to the over-crosslinking and consequent embrittlement. System B, however, showed remarkable retention of the mechanical properties before/after weathering. Nano-indentation results were in good agreement with the tensile properties, showing a similar trend in hardness variations. Although Systems A and C outperformed System B in photooxidation performance, all three systems demonstrated promising results considering no hindered amine light stabilizers (HALS) were used in the formulations. Both photooxidation and mechanical properties of the specimens are expected to improve after addition of HALS.
Towards Design of Sustainable Smart Mobility Services through a Cloud Platform
Authors: Meroux Dominique , Telenko Cassandra , Jiang Zhen , Fu Yan
Published: April 2020

People and their communities are looking for transportation solutions that reduce travel time, improve well-being and accessibility, and reduce emissions and traffic congestion. Although new mobility services like ride-hailing advertise improvements in these areas, closer inspection has revealed a discrepancy between industry claims and reality. Key decision-makers, including citizens, cities and enterprise, and mobility service providers have the opportunity to leverage connected vehicle and connected device data through cloud-based APIs. We propose a GHG data analytics framework that functions on top of a cloud platform to provide unique system-level perspectives on operating transportation services, from procuring the most environmentally and people friendly vehicles to scheduling and designing the services based on data insights. The motivation behind such an approach is two-fold: first, quantification enables transparency to build trust between the mobility service provider and their constituent communities; and second, identifying and acting to improve sustainability improves profitability. Using a benchmark problem with real-world vehicle and mobile device data, we demonstrate the functionality of our GHG analytics framework.
A New Cavitation Algorithm to Support the Interpretation of LIF Measurements of Piston Rings
Authors: Ruch Fabian H. , Wachtmeister Georg
Published: April 2020

Laser induced fluorescence (LIF) is used to investigate oil transport mechanisms under real engine conditions. The engine oil is mixed with a dye that can be induced by a laser. The emitted light intensity from the dye correlates with the residual oil at the sensor position and the resulting oil film thicknesses can be precisely determined for each crank angle. However, the general expectation is not always achieved, e.g. an exact representation of piston ring barrel shapes. In order to investigate the responsible lubrication effects of this behavior, a new cavitation algorithm for the Reynolds equation has been developed. The solution retains the mass conservation and does not use any switch function in its mathematical approach. In contrast to common approaches, no vapor-liquid ratio is used, but one or several bigger bubbles are approximated, as have been observed in other experiments already. As a result, not only the known boundary conditions for the Reynolds equation become unnecessary, but the solution also gives a clearer idea as to the shape of the cavitation bubble. The combination of simulated oil film thicknesses, the resulting cavitation bubbles and the fixed field of view from the LIF sensor allows a reproduction of the measurement signal. The comparison of measurement and simulation exhibits a high correlation, and thus enables a deeper knowledge and understanding of the real conditions inside a combustion engine. On the other hand, it can be seen that effects such as a decrease in the LIF signal in the cavitation area is much lower than would be expected according to the literature.
Non-Contacting Finger Seal Piston for Oil Less Engines
Authors: Boudreau Pascal , Picard Mathieu
Published: April 2020

The current quest to reduce CO2 emissions combined to new technologies has sparked an interest in revisiting radically different engine configuration concepts, such as adiabatic and split-cycle engines. To achieve the full potential of both concepts, the combustion chamber must be sealed without lubricating oil. A promising approach that has yet remained elusive, is to lubricate the piston-liner interface with gases. This paper explores the concept of using non-contacting finger seals to seal piston engines combustion chambers. The finger seals, made of a gas-lubricated pad at the end of a flexible beam, are fixed on a rotating piston that uses the centrifugal force to close the piston-liner gap. A physics-based fluid-structure model is developed to predict finger displacements and sealing performances. The model shows that the radial displacement of the fingers naturally creates a convergent profile with the liner that generates sufficient aerodynamic pressure to maintain a micrometer gap that prevents the piston to contact the liner. The results also show that the achievable leakage area would be similar to that of Wankel rotary engine and friction losses would be negligible compared to those of conventional piston rings. On the other hand, the study reveals challenges that will need to be addressed in order that finger seals be practical in engines, such as the finger torsion, dynamic behavior when exposed to bore distortion as well as the manufacturing tolerances required to ensure contact-free operation.
The Effect of EGR Dilution on the Heat Release Rates in Boosted Spark-Assisted Compression Ignition (SACI) Engines
Authors: Triantopoulos Vassilis , Bohac Stanislav , Martz Jason , Lavoie George , Boehman Andre , Sterniak Jeff , Assanis Dennis
Published: April 2020

This paper presents an experimental investigation of the impact of EGR dilution on the tradeoff between flame and end-gas autoignition heat release in a Spark-Assisted Compression Ignition (SACI) combustion engine. The mixture was maintained stoichiometric and fuel-to-charge equivalence ratio (ϕ′) was controlled by varying the EGR dilution level at constant engine speed. Under all conditions investigated, end-gas autoignition timing was maintained constant by modulating the mixture temperature and spark timing. Experiments at constant intake pressure and constant spark timing showed that as ϕ′ is increased, lower mixture temperatures are required to match end-gas autoignition timing. Higher ϕ′ mixtures exhibited faster initial flame burn rates, which were attributed to the higher laminar flame speeds immediately after spark timing and their effect on the overall turbulent burning velocity. The increasing trends in peak heat release rate and peak autoignition rate as a function of ϕ′ were consistent for all intake pressures ranging from 80 kPa to 150 kPa. For a constant spark timing, the mass fraction burned at the onset of autoignition correlated well with ϕ′, regardless of intake pressure. Reducing the unburned mass fraction at the onset of autoignition was effective at limiting the peak heat release rates. This behavior was attributed to the reduced energy content of the end-gas and also to the reduced end-gas burn rates. Possible explanations for the latter observation were the greater buffer gas effect due to a larger burned gas mass, and the higher reactivity stratification of the end-gas being closer to the walls.
Experimental Evaluation of a Custom Gasoline-Like Blend Designed to Simultaneously Improve ϕ-Sensitivity, RON and Octane Sensitivity
Authors: Lopez Pintor Dario , Dec John , Gentz Gerald
Published: April 2020

ϕ-sensitivity is a fuel characteristic that has important benefits for the operation and control of low-temperature gasoline combustion (LTGC) engines. However, regular gasoline is not very ϕ-sensitive at low-pressure conditions, meaning that intake boosting (typically Pin ≥ 1.3 bar) is required to take advantage of this property. Thus, there is strong motivation to design a gasoline-like fuel that simultaneously improves ϕ-sensitivity, RON and octane sensitivity, to make an improved fuel suitable for both LTGC and modern SI engines. In a previous study [SAE 2019-01-0961], a 5-component regulation-compliant fuel blend (CB#1) was computationally designed; and simulations showed promising results when it was compared to a regular E10 gasoline (RD5-87). The current study experimentally evaluates CB#1 in the Sandia LTGC engine and compares the results with those of RD5-87. The RON and octane sensitivity were improved 1.3 and 3.6 units by CB#1, respectively. Similar amounts of intake heat are required to achieve autoignition of CB#1 and RD5-87 at premixed, naturally aspirated conditions, ensuring that CB#1 can operate under HCCI mode as easily as regular gasoline. Furthermore, similar maximum engine loads can be reached with both CB#1 and RD5-87 under premixed, high-boost conditions. The ϕ-sensitivity was evaluated using two metrics. First, starting from well-mixed conditions, the change in CA10 with a specific amount of fuel stratification provides a metric of how the ϕ-sensitivity advances the ignition. Second, the amount of CA50 advancement without knock that is achievable with stratification provides a metric of how the ϕ-sensitivity spreads the heat release. Both metrics showed that CB#1 has a greater ϕ-sensitivity than RD5-87. Additionally, CB#1 has a lower peak heat release rate than RD5-87 for stratified operation with the same combustion phasing because of the larger spread of heat release, leading to lower combustion noise and lower knock propensity. Finally, CB#1 was found to be a more suitable fuel to work with ignition enhancers, such as EHN, compared to RD5-87.
Computational Modeling of Diesel Spray Combustion with Multiple Injections
Authors: Zhou Qiyan , Lucchini Tommaso , D'Errico Gianluca , Maes Noud , Somers Bart , Lu Xing-cai
Published: April 2020

Multiple injection strategies are commonly used in conventional Diesel engines due to the flexibility for optimizing heat-release timing with a consequent improvement in fuel economy and engine-out emissions. This is also desirable in low-temperature combustion (LTC) engines since it offers the potential to reduce unburned hydrocarbon and CO emissions. To better utilize these benefits and find optimal calibrations of split injection strategies, it is imperative that the fundamental processes of multiple injection combustion are understood and computational fluid dynamics models accurately describe the flow dynamics and combustion characteristics between different injection events. To this end, this work is dedicated to the identification of suitable methodologies to predict the multiple injection combustion process. Two different approaches: Representative Interactive Flamelet model (RIF) and Tabulated Flamelet Progress Variable (TFPV) are compared and multiple n-dodecane Spray A injections from the Engine Combustion Network are simulated using the RANS methods with both standard k − ε and k − ω SST models. Evaluations of different turbulence and combustion models are carried out by comparing computed and measured data in terms of the mixing, penetration, first- and second-stage ignition characteristics, flame structures and soot formation.
Off-Road Fuel Cell Vehicle Analysis and Development with a Model-Based Design Approach
Authors: Kigezi Tom , Kim Bill Insup , Jokela Tommi , Gao Bo
Published: April 2020

Fuel cell and battery electric powertrains are maturing zero-emission technologies expected to complement each other in the future. At present, battery electric powertrains have emerged competitive for urban light-duty transportation while fuel cell powertrains have emerged competitive in heavy-duty commercial transportation, alongside conventional internal combustion engine propulsion. This paper assesses the benefit for fuel cell powertrains in off-road vehicles, taking into account current and target industry data for powertrain components. Specific emphasis is placed on three important aspects, namely driving range, vehicle weight, and vehicle cost. A model-based design approach is then adopted to size the powertrain to meet a set of performance requirements. Owing to the high performance demands of off-road vehicles such as high gradeability and payload capacity, the paper evaluates the merits of a two-speed transmission in comparison to a single speed transmission under drive cycle and performance testing scenarios. A detailed fuel cell model is adopted and validated with real vehicle test data, also from which a highly scalable energy management system is systematically developed. This work adds to a growing industry effort towards zero-emission electrification of off-road vehicles.
Accuracy of Speed Change Measured by Event Data Recorders during Oblique Offset Frontal Impacts
Authors: Curtat Jean-Loup , Wilkinson Craig , Siegmund Gunter P.
Published: April 2020

Data downloaded from event data recorders (EDRs) integrated into the airbag systems of passenger vehicles can be key evidence for collision investigators. Often the EDR data includes information about the severity of the collision in terms of the longitudinal and lateral speed changes experienced by the vehicle. Previous studies have shown that for collisions with small lateral speed changes, the accuracy of the reported longitudinal speed change varies with manufacturer and magnitude. The goal of this study was to quantify the accuracy of EDR-reported speed changes in high-speed angled collisions with larger lateral speed change components. Data from 25 crash tests conducted for the National Highway Traffic Safety Administration’s (NHTSA’s) Oblique Offset Frontal Impact Research and Development Program were used in this study. The accuracy of the EDR-reported speed change was evaluated by comparing it to the longitudinal and lateral speed changes integrated from the independent reference accelerometers at the vehicle’s center of gravity. For vehicles with EDRs that also reported acceleration data, the speed change calculated by integrating the EDR-reported acceleration data was also compared to the speed change integrated from the reference accelerometers. The largest errors were seen in the two 2015 Honda Fit tests that under reported the longitudinal speed change by about 10 km/h. Although the average differences between the EDR-based speed change and the reference speed change were not significantly different from zero, the range of errors was large and varied between the different methods of extracting speed change and between the different components of the speed change The errors on EDR-reported longitudinal and lateral speed changes led to errors on the resultant speed change of up to 12 km/h under or 5 km/h over the actual speed change. The absolute errors for the longitudinal and lateral components of the speed change were similar but their relative errors were not. The speed changes computed by integrating the EDR’s acceleration data were on average less accurate than the speed changes reported and tabled in the EDR reports. The errors on the resultant speed change calculated from integrating the EDR-reported accelerations were up to 18 km/h under or 10 km/h over the actual speed change. There was considerable variation in the accuracy for different vehicle makes and models, with the largest errors observed in some Honda vehicles. The results of this study improve our understanding of the accuracy of EDR-reported speed change in high-severity angled collisions.