bluuebunny/crossref_metadata_2025 huggingface dataset:
Bake Hardening Behavior of DP, TBF, and PHS Steels with Ultimate Tensile Strengths Exceeding 1 GPa
Authors: Blesi Brandon W. , Smith Charles , Matlock David K. , De Moor Emmanuel
Published: April 2020

Third generation advanced high strength steels (AHSS) have been developed combining high strength and formability, allowing for lightweighting of vehicle structural components. These AHSS components are exposed to paint baking operations ranging in time and temperature to cure the applied paint. The paint baking treatment, combined with straining induced from part forming, may lead to increased in-service component performance due to a strengthening mechanism known as bake hardening. This study aims to quantify the bake hardening behavior of select AHSS grades. Materials investigated were press hardenable steels (PHS) 1500 and 2000; transformation induced plasticity (TRIP) aided bainitic ferrite (TBF) 1000 and 1200; and dual phase (DP) 1000. The number designations of these grades refer to minimum as-received ultimate tensile strengths in MPa. Paint baking was simulated using industrially relevant times and temperatures from 15 to 60 min and 120 to 200 °C, respectively. Samples were prestrained 0, 2, or 5 pct to replicate part forming. Bake hardening values ranging from 90 to 140 MPa were observed for DP and TBF grades that were prestrained 2 pct and baked at 170 °C for 20 min. However, ductility diminished for these steels when subjected to 5 pct prestrain with uniform elongations after baking decreasing to 1 pct in some instances. PHS steels, on the other hand, showed substantial increases in yield strength without prestrain. Increases of 122 and 175 MPa were recorded for PHS 1500 and PHS 2000, respectively, following baking at 160 °C for 60 min. However, ultimate tensile strengths decreased due to reduced strain hardening, while total elongations decreased slightly.
Strategy for Optimizing an F1 Car’s Performance Based on FIA Regulations
Authors: Bopaiah Karan , Samuel Stephen
Published: April 2020

The aim of the present work is to propose a control strategy for maximizing the performance of a Formula One (F1) car through numerical simulation for 2021 regulations taking 2019 regulations as a benchmark. This study has developed an engine-powertrain model of an F1 car with real world driver data for estimating the vehicle’s full throttle performance. The maximum possible energy recovered, stored and deployed by the Energy Recovery System (ERS) was estimated for the first 10 circuits in the 2019 FIA Formula One World Championship® Race Calendar. A 1.6L V6 Internal Combustion Engine (ICE), as well as, a full vehicle was modelled according to the 2019 Federation Internationale de l'Automobile (FIA) Formula One technical regulations using GT-Suite software. The model was validated against the experimental data. The data for validation was extracted from On- Board videos using Optical Character Recognition (OCR) and FIA regulations. Strategy for qualifying has been developed for all 10 circuits and compared. Strategies used by different drivers on different circuits are analysed and the optimum strategy for maximizing the Power Unit’s (PU) performance is proposed.

Findings show that the data acquired from FIA Formula One on-board videos from the F1 TV App is highly accurate in conjunction to the official lap time with an error of less than 1%. The full car model is able to meet the Target Vehicle Speed at the required gear number and follow the FIA regulations at all times. Factors affecting the performance of the PU such as Average vehicle speed and the Motor Generator Unit-Kinetic (MGU-K) deployment speed have been found and quantified. Driver to Driver variation in the MGU-K deployment speed for maximizing performance during qualification has been quantified. It was found that the winning drivers had higher Average vehicle speed and MGU-K deployment speed which resulted in better performance from the PU. The maximum possible energy recovered per lap by the MGU-K is analysed for both the qualification and race laps. It was found that the energy recovered per lap by the MGU-K is higher in race laps as compared to qualification laps because of increase in the vehicle mass due to fuel weight. Lastly, Strategies have been proposed to maximise the performance of the PU for qualification and race.
Analysis of the Water Addition Efficiency on Knock Suppression for Different Octane Ratings
Authors: Franken Tim , Seidel Lars , Matrisciano Andrea , Mauss Fabian , Kulzer André C. , Schuerg Frank
Published: April 2020

Water injection can be applied to spark ignited gasoline engines to increase the Knock Limit Spark Advance and improve the thermal efficiency. The Knock Limit Spark Advance potential of 6 °CA to 11 °CA is shown by many research groups for EN228 gasoline fuel using experimental and simulation methods. The influence of water is multi-layered since it reduces the in-cylinder temperature by vaporization and higher heat capacity of the fresh gas, it changes the chemical equilibrium in the end gas and increases the ignition delay and decreases the laminar flame speed. The aim of this work is to extend the analysis of water addition to different octane ratings. The simulation method used for the analysis consists of a detailed reaction scheme for gasoline fuels, the Quasi-Dimensional Stochastic Reactor Model and the Detonation Diagram. The detailed reaction scheme is used to create the dual fuel laminar flame speed and combustion chemistry look-up tables. The Detonation Diagram is used as a novel approach in the Quasi-Dimensional Stochastic Reactor Model to evaluate the auto-ignition characteristic in the end gas and determine if it is a harmless deflagration or developing detonation. First, the Quasi-Dimensional Stochastic Reactor Model is trained for three engine operating points and a RON95 E10 fuel. Its performance is evaluated based on experimental results of a single cylinder research engine. Subsequently, different spark timings and water-fuel ratios are investigated for different Primary Reference Fuels. The results outline that water addition can effectively reduce the strength of auto-ignition in the end gas for different Primary Reference Fuels. Thereby, it can be stated that the reduction of the auto-ignition strength through water addition by 50 - 80 % water-fuel ratio for high octane number fuels corresponds to the spark timing delay of 6 °CA or an increase of research octane number by 10 points.
Infrared/Visible Optical Diagnostics of RCCI Combustion with Dieseline in a Compression Ignition Engine
Authors: Sequino Luigi , Mancaruso Ezio , Monsalve-Serrano Javier , Garcia Antonio
Published: April 2020

Compression ignition engines are widely used for transport and energy generation due to their high efficiency and low fuel consumption. To minimize the environmental impact of this technology, the pollutant emissions levels at the exhaust are strictly regulated. To reduce the after-treatment needs, alternative strategies as the low temperature combustion (LTC) concepts are being investigated recently. The reactivity controlled compression ignition (RCCI) uses two fuels (direct- and port- injected) with different reactivity to control the in-cylinder mixture reactivity by adjusting the proportion of both fuels. In spite of the proportion of the port-injected fuel is typically higher than the direct-injected one, the characteristics of the latter play a main role on the combustion process. Use of gasoline for direct injection is attractive to retard the start of combustion and to improve the air-fuel mixing process. In this work, the influence of the direct-injected fuel properties on RCCI combustion mode is studied in an optical compression ignition engine. Gasoline fuel is injected in the intake manifold while a blend of gasoline and diesel (a.k.a. dieseline) is directly injected into the cylinder. Non-conventional optical diagnostics in the visible and infrared spectra are applied for the direct investigation of the in-cylinder phenomena during the injection and the combustion processes. A low-luminosity, mainly kinetically controlled combustion mode has been observed.
Assessing the Impact of Lubricant and Fuel Composition on LSPI and Emissions in a Turbocharged Gasoline Direct Injection Engine
Authors: Kar Abhishek , Huisjen Andrew , Aradi Allen , Reitz Jannik , Iqbal Asim , Haumann Karin , Kensler Jennifer , Hardman Ken , Mainwaring Robert , Remmert Sarah
Published: April 2020

Downsized turbocharged gasoline direct injection (TGDI) engines with high specific power and torque can enable reduced fuel consumption in passenger vehicles while maintaining or even improving on the performance of larger naturally aspirated engines. However, high specific torque levels, especially at low speeds, can lead to abnormal combustion phenomena such as knock or Low-Speed Pre-Ignition (LSPI). LSPI, in particular, can limit further downsizing due to resulting and potentially damaging mega-knock events. Herein, we characterize the impacts of lubricant and fuel composition on LSPI frequency in a TGDI engine while specifically exploring the correlation between fuel composition, particulate emissions, and LSPI events. Our research shows that: (1) oil composition has a strong impact on LSPI frequency and that LSPI frequency can be reduced through a carefully focused approach to lubricant formulation. In addition, (2) we observed significant improvement potential in Brake Mean Effective Pressure (BMEP) achievable with zero LSPI events using both experimental and market-representative lubricant formulations. Finally, (3) fuels blended with high polyaromatic content were shown to increase LSPI frequency significantly; these fuels also caused a significant increase in particulate mass (PM) and particulate number (PN) emissions. In this paper, we discuss the above results along with the development and use of a high-fidelity test method to measure LSPI under steady-state test conditions.
Detailed Analyses and Correlation of Fuel Effects on Stochastic Preignition
Authors: Swarts Andre , Chapman Elana , Costanzo Vincent
Published: April 2020

Stochastic or Low-Speed Preignition (SPI or LSPI) is an undesirable abnormal combustion phenomenon encountered in spark-ignition engines. It is characterized by very early heat release and high cylinder pressure and can cause knock, noise and ultimately engine damage. Much of the focus on mitigating SPI has been directed towards the engine oil formulation, leading to the emergence of the Sequence IX test and second-generation GM dexos® oil requirements. Engine design, calibration and fuels also contribute to the prevalence of SPI. As part of a recently completed research consortium, a series of engine tests were completed to determine the impact of fuel composition on SPI frequency. The fuel blends had varying levels of paraffins, olefins, aromatics and ethanol. Engine tests were performed on a 2-liter turbocharged, direct-injection spark-ignition engine and comprised of multiple repeats of low-speed, high-load, steady-state test segments, interspersed with low load segments, with engine calibration and boundary conditions adjusted to amplify the appearance of SPI. Comprehensive analyses of the fuel properties and chemical composition revealed the key fuel characteristics, notably the Particulate Mass Index (PMI), that were best correlated with the appearance of SPI. In addition, the impact of fuel composition and properties on the severity of preignition events were examined by comparing the peak knock values for all abnormal combustion cycles. The frequency of multi-cycle events was also investigated. The paper suggests that not only the number of preignition events but also the severity of preignition should be considered when evaluating fuel impacts on SPI. Most importantly, for this work, is the determination that particulate forming tendency of the fuel correlates to its SPI tendency, although whether this is causal or correlational cannot be discerned.
Efficient Surrogate-Based NVH Optimization of a Full Vehicle Using FRF Based Substructuring
Authors: Park Inseok , Papadimitriou Dimitrios
Published: April 2020

The computer simulation with the Finite Element (FE) code for the structural dynamics becomes more attractive in the industry. However, it normally takes a prohibitive amount of computation time when design optimization is performed with running a large-scale FE simulation many times. Exploiting Dynamic Structuring (DS) leads to alleviating the computational complexity since DS necessities iterative reanalysis of only the substructure(s) to be optimally designed. In this research, Frequency Response Function (FRF) based substructuring is implemented to realize the benefits of DS for fast single- and multi-objective evolutionary design optimization. Also, Differential Evolution (DE) is first combined with two sorting approaches of Non-dominated Sorting Genetic Algorithm II (NSGA-II) and Infeasibility Driven Evolutionary Algorithm (IDEA) for effective constrained single- and multi-objective evolutionary optimization. The effectiveness of the proposed algorithm (NSGA-II/DE-IDEA) is verified using several test functions for constrained single- and multi-objective optimization. To circumvent the need for frequent time-consuming simulation runs, Kriging surrogate models are established by interpolating the responses simulated at the sample points, which are generated by executing an Optimal LHS algorithm. Besides, the Morris method is implemented to leave out unimportant design variables. A constrained single-objective and a constrained multi-objective NVH design optimization of a truck are carried out to demonstrate the surrogate-based design optimization process involving FRF based substructuring and the proposed algorithm.
Prediction of the Variation on Steering Wheel Shimmy due to Tangential and Radial Force Variation of the Tyres
Authors: Shurpali Madhu
Published: April 2020

The objective of this work is to develop a process that predicts the amount of steering wheel shimmy in a vehicle due to the tangential and radial force variation in the Tyre/Wheel assembly and also other components affecting shimmy. Steering wheel shimmy is defined as the torsional oscillation of the steering wheel due to excitation at the wheels. The tangential and radial force variation was modelled based on test data and applied on the wheels as excitation. Variation of these forces with the vehicle velocity was considered. The various factors that affect shimmy were then established. These factors were then divided into two categories - Geometric and Non-Geometric. A DOE was done, while considering the manufacturing variations, to study the sensitivity of those factors on shimmy. The DOE results were used to fit a regression model that predicts the shimmy velocity while considering the factors as inputs. The regression model was then considered for a Montecarlo simulation to estimate the distribution of shimmy velocity. A Normal or Weibull distribution was considered for the MonteCarlo Simulation for each of the factors in the DOE study. This distribution was then compared against a target. The target was used to design the suspension such that it is robust enough to withstand the manufacturing variations of the factors effecting shimmy.
Investigation of Transient Aerodynamic Effects on Public Roads in Comparison to Individual Driving Situations on a Test Site
Authors: Jessing Christoph , Wilhelmi Henning , Wittmeier Felix , Wagner Andreas , Wiedemann Jochen , Dillmann Andreas
Published: April 2020

Natural wind, roadside obstacles, terrain roughness, and traffic influence the incident flow of a vehicle driven on public roads. These transient on-road conditions differ from the idealized statistical steady-state flow environment utilized in CFD simulations and wind tunnel experiments. To understand these transient on-road conditions better, measurements were performed on German public highways and on a test site. A compact car was equipped with a measurement system that is capable of determining the transient airflow around the vehicle and the vehicle’s actual driving state. This vehicle was driven several times on a predefined 200 km long route to investigate different traffic densities on public highways in southern Germany. During the tests the transient incident flow and pressure distribution on the vehicle surface were measured. With the same test vehicle, individual driving situations were recreated on a test site under weather conditions similar to those of the tests on public roads. This paper presents a comparison of the aerodynamic characteristics measured on public highways and on the test site. Two driving situations were examined at the test site: one is driving the test vehicle without traffic and the other is driving behind a box truck in different distances. This paper compares the realistic properties of the turbulent flow structures and the surface pressure around the vehicle during on-road driving in public traffic with those measured on the testing site. The purpose of this study is to investigate the possibility of reproducing the representative driving on public highways with a simplified approach.
Impact of Mixed Traffic on the Energy Savings of a Truck
Platoon
Authors: McAuliffe Brian , Raeesi Arash , Lammert Michael , Smith Patrick , Hoffman Mark , Bevly David
Published: April 2020

A two-truck platoon based on a prototype cooperative adaptive cruise control
(CACC) system was tested on a closed test track in a variety of realistic
traffic and transient operating scenarios - conditions that truck platoons are
likely to face on real highways. The fuel consumption for both trucks in the
platoon was measured using the SAE J1321 gravimetric procedure as well as
calibrated J1939 instantaneous fuel rate, serving as proxies to evaluate the
impact of aerodynamic drag reduction under constant-speed conditions. These
measurements demonstrate the effects of: the presence of a
multiple-passenger-vehicle pattern ahead of and adjacent to the platoon, cut-in
and cut-out manoeuvres by other vehicles, transient traffic, the use of
mismatched platooned vehicles (van trailer mixed with flatbed trailer), and the
platoon following another truck with adaptive cruise control (ACC). These
scenarios are intended to address the possibility of “background aerodynamic
platooning” impacting realized savings on public roads. Using calibrated J1939
fuel rate analysis, fuel savings for curved track sections versus straight track
sections were also evaluated for these scenarios, highlighting differences in
the implementation of the CACC control strategies compared to a stock ACC
implementation. The use of different trailer types and the presence of
passenger-vehicle traffic patterns showed a measurable impact on platoon
performance in some conditions, but the basic fuel savings trends were
retained.
Pre-Deployment Testing of Low Speed, Urban Road Autonomous Driving in a Simulated Environment
Authors: Li Xinchen , Arul Doss Aravind Chandradoss , Aksun Guvenc Bilin , Guvenc Levent
Published: April 2020

Low speed autonomous shuttles emulating SAE Level L4 automated driving using human driver assisted autonomy have been operating in geo-fenced areas in several cities in the US and the rest of the world. These autonomous vehicles (AV) are operated by small to mid-sized technology companies that do not have the resources of automotive OEMs for carrying out exhaustive, comprehensive testing of their AV technology solutions before public road deployment. Due to the low speed of operation and hence not operating on roads containing highways, the base vehicles of these AV shuttles are not required to go through rigorous certification tests. The way these vehicles’ driver assisted AV technology is tested and allowed for public road deployment is continuously evolving but is not standardized and shows differences between the different states where these vehicles operate. Currently, AVs and AV shuttles deployed on public roads are using these deployments for testing and improving their technology. However, this is not the right approach. Safe and extensive testing in a lab and controlled test environment including Model-in-the-Loop (MiL), Hardware-in-the-Loop (HiL) and Autonomous-Vehicle-in-the-Loop (AViL) testing should be the prerequisite to such public road deployments. This paper presents three dimensional virtual modeling of an AV shuttle deployment site and simulation testing in this virtual environment. We have two deployment sites in Columbus of these AV shuttles through the Department of Transportation funded Smart City Challenge project named Smart Columbus. The Linden residential area AV shuttle deployment site of Smart Columbus is used as the specific example for illustrating the AV testing method proposed in this paper.
Integration of Autonomous Vehicle Frameworks for Software-in-the-Loop Testing
Authors: Bachuwar Sanket , Bulsara Ardashir , Dossaji Huzefa , Gopinath Aditya , Paredis Chris , Pilla Srikanth , Jia Yunyi
Published: April 2020

This paper presents an approach for performing software in the loop testing of autonomous vehicle software developed in the Autoware framework. Autoware is an open source software for autonomous driving that includes modules such as localization, detection, prediction, planning and control [8]. Multitudes of autonomous driving frameworks exist today, each having its own pros and cons. Often, MATLAB-Simulink is used for rapid prototyping, system modeling and testing, specifically for the lower-level vehicle dynamics and powertrain control features. For the autonomous software, the Robotic Operating System (ROS) is more commonly used for integrating distributed software components so that they can easily share information through a publish and subscribe paradigm. Thorough testing and evaluation of such complex, distributed software, implemented on a physical vehicle poses significant challenges in terms of safety, time, and cost, especially when considering rare edge cases. Virtual prototyping is therefore a crucial enabler in the development of autonomous software. In a simulated environment, many traffic scenarios under a variety of environmental conditions can be quickly evaluated, at low cost, without safety concerns. In this paper, we report on a simulation environment consisting of three simulation tools. PreScan (by Siemens/TASS) combined with Simulink (by Mathworks) is used for simulating how the vehicle interacts with the environment: sensors, actuators, the vehicle dynamics and powertrain. The autonomy software is emulated directly in Autoware.AI on top of ROS. To evaluate the autonomous software, synthetic data from the sensors simulated in PreScan are published to ROS where they are processed by the autonomy stack. Similarly, the control signals generated by the autonomy stack in Autoware are subscribed to by PreScan where they serve as input to the virtual vehicle model. The paper describes in detail the integration of PreScan and Autoware, illustrates this integration for object detection using a monocular camera, and characterizes the performance in terms of message transfer speed.
Scenario Analysis and Control Comparison for a High Speed Autonomous Vehicle
Authors: Donikian Vatche , Bell Joseph , Washington Gregory
Published: April 2020

This paper studies the simulation and control of an autonomous dragster. Four scenarios are provided that are critical to vehicle and driver safety in drag racing. Equations are then created to model the behavior during these safety scenarios. The use of a kinematic bicycle model and a Newtonian wheel stand model are discussed for plane-of-motion and out-of-plane vehicle movement, respectively. A separate controller is designed for each model by comparing different control methods. Proportional-Integral-Derivative (PID) control, optimal control, and model predictive control (MPC) are presented and applied to the models. The models are simulated from a speed of 75 m/s, being the estimated top speed of the research vehicle, up to a top speed of 150.5 m/s which is in alignment with the highest recorded speed of a dragster. The comparison of the control techniques yields MPC as superior for the bicycle model and PID as sufficient for the wheel stand model. Latency of the system is also discussed and accounted for in the system.
A Decision Based Mobility Model for Semi and Fully Autonomous Vehicles
Authors: Pandey Vijitashwa , Slon Christopher , Deschenes Line , Gorsich David , Jayakumar Paramsothy
Published: April 2020

With the emergence of intelligent ground vehicles, an objective evaluation of vehicle mobility has become an even more challenging task. Vehicle mobility refers to the ability of a ground vehicle to traverse from one point to another, preferably in an optimal way. Numerous techniques exist for evaluating the mobility of vehicles on paved roads, both quantitatively and qualitatively, however, capabilities to evaluate their off-road performance remains limited. Whereas a vehicle’s off-road mobility may be significantly enhanced with intelligence, it also introduces many new variables into the decision making process that must be considered. In this paper, we present a decision analytic framework to accomplish this task. In our approach, a vehicle’s mobility is modeled using an operator’s preferences over multiple mobility attributes of concern. We also provide a method to analyze various operating scenarios including the ability to mitigate uncertainty in the vehicles inputs. An example of this is the collection of soil properties data using techniques such as remote sensing. Operators of these vehicles are interested in finding the value of collecting such information. We present our approach on a vehicle selection decision between ground vehicles exhibiting different levels of autonomy.
High Strain Rate Tensile Behavior of 1180MPa Grade Advanced High Strength Steels
Authors: Savic Vesna , Hector Louis , Alturk Rakan , Enloe Charles
Published: April 2020

Tensile behavior of advanced high strength steel (AHSS) grades with strengths up to 980 MPa has been extensively studied. However, limited data is found in literature on the tensile behavior of steels with tensile strengths of the order of 1180 MPa, especially at nominal strain rates up to 500/s. This paper examines tensile flow behavior to fracture of four different 1180 MPa grade steels at strain rates of 0.005/s, 0.5/s, 5/s, 50/s and 500/s using an experimental methodology that combines a servo-hydraulic tester and high speed digital image correlation. Even though the strength increase with the strain rate is consistent between the four different materials, the total elongation increase with the strain rate varies widely. Some insights as to why this occurs from examination of the steel microstructure and variation of retained austenite with strain are offered.
A New Testing Method to Evaluate Edge Cracking with Considerations of the Shear Clearance and Press Speed
Authors: Gu Jiahui , Zoller Laura , Kim Hyunok
Published: April 2020

As the automotive industry increasingly adopts Advanced High Strength Steel (AHSS) for the vehicle light-weighting and crashworthiness, the edge cracking significantly increases in stamping AHSS. Different lab-scale test methods such as the ISO standard hole-expansion test and the half specimen dome test are available to evaluate edge formability. However, none of these lab-scale testing methods emulates production conditions such as various shear clearances, part complexity, and shearing speed associated with the mechanical or hydraulic press operation. To address these limitations of the available testing methods, a new punching and stamping test was developed.

This paper introduces the simulation and experimental approach in developing this unique testing method to design the peanut-shaped hole that is sensitive to edge cracking in stamping. Three different sheet materials, DP780, 980 GEN3, and aluminum 6016-T4 were tested to validate the reliability of the newly developed testing method. Selected materials were punched with two different shear clearances between 10~20% that are commonly used for industrial applications. Also, two different press motions, conventional mechanical press motion and variable-speed servo press motion, were used for punching the peanut-shaped holes. The punched-hole blank was subsequently formed with the stamping tool. During the forming test, the die stroke corresponding to the edge cracking was detected by the load analyzer from the servo press. Strain distribution on the tested parts was measured and compared using the optical strain measurement tool, ARGUS. The work-hardening on the sheared edge was quantified with the hardness measurements. The edge formability was evaluated with the measured die stroke corresponding to the edge cracking and strain measurements.
Downsized-Boosted Gasoline Engine with Exhaust Compound and Dilute Advanced Combustion
Authors: Dernotte Jeremie , Najt Paul M. , Durrett Russell P.
Published: April 2020

This article presents experimental results obtained with a disruptive engine platform, designed to maximize the engine efficiency through a synergetic implementation of downsizing, high compression-ratio, and importantly exhaust-heat energy recovery in conjunction with advanced lean/dilute low-temperature type combustion. The engine architecture is a supercharged high-power output, 1.1-liter engine with two-firing cylinders and a high compression ratio of 13.5: 1. The integrated exhaust heat recovery system is an additional, larger displacement, non-fueled cylinder into which the exhaust gas from the two firing cylinders is alternately transferred to be further expanded.

The main goal of this work is to implement in this engine, advanced lean/dilute low-temperature combustion for low-NOx and high efficiency operation, and to address the transition between the different operating modes. Those include well-mixed charge compression-ignition at low-load, and a mixed-mode combustion at higher loads, before transitioning to boosted homogenous and stochiometric spark-ignited combustion. Here, the mixed-mode combustion strategy is composed of a deflagration of a stratified mixture created by a late direct injection, then triggering a controlled autoignition of the surrounding gas, improving the robustness of lean/dilute combustion. The paper describes the key features of the engine and details regarding the combustion and multi-mode valve strategies.

The experiments were performed under steady-state operation at 2000 rpm, from 1 to 11 bar IMEPn and naturally aspirated conditions. The engine demonstrated great efficiency gains compared to a conventional naturally-aspirated and downsized-boosted spark-ignited engines. The piston-compounding exhaust-heat recovery system contributes to up to 10% of the total efficiency improvement, while lean/dilute advanced combustion increases the fuel economy by up to 38% compared to a naturally aspirated engine, and up to 22%, compared to a downsized-boosted engine. NOx emissions target was met using high-levels of internal and external dilution in mixed-mode combustion operation, as well as by optimizing the injection and ignition strategy. Finally, the analysis shows that a seamless transition between the different valving strategies is achievable in support of robust transient operation.
An Enhanced
Σ
-Y Spray Atomization Model Accounting for Diffusion due to Drift-Flux Velocities
Authors: Pandal Adrian , Rahantamialisoa Faniry , Ningegowda B M , Battistoni Michele
Published: April 2020

Spray modeling techniques have evolved from the classic DDM (Discrete Drops Method) approach, where the continuous liquid jet is discretized into “drops” or “parcels” till advanced spray models often based on Eulerian approaches. The former technique, although computationally efficient, is essentially inadequate in highly dense jets, as in the near nozzle region of compression ignition engines, while the latter could lead to extreme levels of computational effort when resolved interface capturing methods, such as VoF (Volume of Fluids) and LS (Level-Set) types, are used. However, in a typical engineering calculation, the mesh resolution is considerably coarser than in these high fidelity computations. If one presumes that these interfacial details are far smaller than the mesh size, smoothing features over at least one cell ultimately results in a diffuse-interface treatment in a Eulerian framework. Therefore, it is explained that currently the greatest interest is focused on the development of diffuse interface computational models which use a variable called surface density of the interface (Σ), solved using an averaged or filtered transport equation, to model the atomization process. However, in this type of approach a single-fluid formulation is used solving a single momentum equation but neglecting some features of the relative velocity between the liquid and the gas phases. This practice is not an issue for diesel sprays under nominal operating conditions of current engines, i.e., under high injection pressure and chamber density. Nevertheless, in certain combustion strategies, due to lower ambient densities (highly premixed combustion) or the usage of substitute fuels, the slip between phases becomes more important and must be fully considered. In this work, we propose a new developed Σ-Y Spray Atomization Model that accounts for diffusion due to Drift-Flux velocities, providing a predictive behavior under all engine conditions. In addition, the proposed formulation creates a mechanism by which the interfacial dynamics can impact the transport of the liquid mass fraction, therefore, making the interfacial density an active scalar, fully coupled with the rest of the flow, overcoming the limitations of previous formulations.
Detailed Analysis of U.S. Department of Energy Engine Targets Compared to Existing Engine Technologies
Authors: Islam Ehsan , Moawad Ayman , Vijayagopal Ram , Rousseau Aymeric
Published: April 2020

The U.S. Department of Energy, Vehicle Technologies Office (U.S. DOE-VTO) has been developing more energy-efficient and environmentally friendly highway transportation technologies that would enable the United States to burn less petroleum on the road. System simulation is an accepted approach for evaluating the fuel economy potential of advanced (future) technology targets. U.S. DOE-VTO defines the targets for advancement in powertrain technologies (e.g., engine efficiency targets, battery energy density, lightweighting, etc.) Vehicle system simulation models based on these targets have been generated in Autonomie, reflecting the different EPA classifications of vehicles for different advanced timeframes as part of the DOE Benefits and Scenario (BaSce) Analysis. It is also important to evaluate the progress of these component technical targets compared to existing technologies available in the market. This paper will present an approach based on a large-scale simulation process, where simulations are performed over standard regulatory driving cycles for different vehicle classes over a range of timeframes by implementing the technology advancement targets set by the U.S. DOE-VTO. This approach would further evaluate the potential impact of different VTO engine targets for different technologies and provide a comparison with existing engine technologies available in the market.
Bicycle Braking Performance Testing and Analysis
Authors: Famiglietti Nicholas , Nguyen Benjamin , Fatzinger Edward , Landerville Jon
Published: April 2020

The goal of this study was to determine bicycle braking performance, while considering different brake designs and applications. Eight bicycles were used to perform brake-to-stop tests: two full suspension mountain bikes, two hybrid bikes, one beach cruiser, one BMX bike, one road bike, and one single speed bicycle. The standardized brake testing procedure consisted of rear only brake application and both front and rear brake application. In order to maintain brake application consistency, a single rider performed all series of the brake tests at the same location, within a designated brake zone on dry asphalt. The tests were performed at initial velocities of 11 to 21 mph. For each test, the rider accelerated to the test speed and, upon entering the brake zone, applied maximum braking effort while maintaining a natural upright position in order to minimize lean. The associated skid marks deposited from wheel lock-up were verified, measured, and documented onsite. Bicycle wheel lock-up was verified if needed via video analysis. The bicycles’ deceleration rates were measured with a Midé Slam Stick X accelerometer, VBOX Sport, and calculated from the deposited skid marks. The deceleration rates measured using the Slam Stick X ranged between 0.40 - 0.71 g for front and rear brake application and 0.25 - 0.37 g for rear only brake application, across all bicycle types. Bicycles with rear coaster brake setups, such as the beach cruiser, braked at an average deceleration rate of 0.25 - 0.36 g. Bicycles with caliper and disc brake setups exhibited an average deceleration rate range of 0.27 - 0.36 g for rear only brake application. Additionally, the incipient lock-up phase was analyzed for distance travelled, speed change, duration, and kinetic energy loss.
Driver Response to Right Turning Path Intrusions at Signalized Intersections
Authors: Ziraldo Erika , Attalla Shady , Kodsi Sam , Oliver Michele
Published: April 2020

Previously researched path intrusion scenarios include left-turning hazard vehicles which intrude laterally across the path of the through driver. A right turning vehicle, however, creates a scenario where a hazard which was initially travelling perpendicular to the driver can intrude into the through driver’s path without also occupying the adjacent through lanes. This hazard scenario has not been previously investigated. The purpose of this research was to determine driver response time (DRT) and response choice to a right turning vehicle that merges abruptly into the lane of the oncoming through driver.

Using an Oktal full car driving simulator, 107 licenced drivers (NFemale = 57, NMale = 50) completed a five-minute practice drive followed by a ten-minute experimental drive containing two conditions of the right turn hazard, presented in a counterbalanced order. In one condition, the hazard vehicle was stopped with its front bumper at the stop bar before accelerating into the path of the participant driver. In the other condition, the hazard vehicle approached the intersection and turned at a constant speed. DRT was defined as the time between when the hazard vehicle crossed the stop bar and when the participant driver reacted by touching the brake pedal or swerving.

There was a significant difference in DRT (p < 0.001) between the two hazard conditions with drivers responding earlier to the right turning vehicle when it was initially in motion. In both scenarios, approximately half of the through drivers swerved in response to the hazard vehicle. Participants who chose to swerve were slower on average, although this response type did not result in significantly more collisions (χ2(2) = 2.02, p = 0.14).
Development of a Novel Method to Simulate Cavity Preservation in Automotive Industry
Authors: Chitneedi Bhargav Krishna , Schifko Martin , Verma Kevin , Menon Muraleekrishnan , NAIR Vishal
Published: April 2020

Corrosion protection is a major topic of research for automotive manufacturers and major suppliers. The most critical parts affected by corrosion are the pillars and cavities. Automotive manufacturers spend a lot of effort to improve protection layers as much as possible to increase the longevity of their products. The Electro-Coat Paint Operation (ELPO) or E-Coat process is key in achieving this goal. Unfortunately, often the electric current does not reach all the areas very well and resulting in undercoating. Also, the consequent baking process might see the ovens not achieving the desired temperatures into the cavities. As a fact it often happens that these areas are exposed by undercoating, and hence undermining the quality of corrosion protection.

Some car manufacturers investigate one level more to assure a good quality of corrosion protection also within cavities, by applying wax. This wax coating process aims to cover all problematic areas in a way to make cavities more resistant to unfriendly conditions such as rain, snow, and salt. At present, waxing solves those problems quite well. However, the wax is an expensive product and car manufacture investigate to minimize the material cost while keeping quality as high as possible.
Metal Belt CVT Seizure Monitoring System Using Wear Debris Analysis and Particle Measurement
Authors: Matsumoto Kenji , Tokunaga Tatsuya , Mori Jun , Mihara Yuji , Kawabata Masahiko
Published: April 2020

An apparatus that automatically samples lubricating oil and measures the size distribution of particles in the oil has been developed in order to monitor the state of engines and transmissions in operation. It is a widely known fact that when an engine or transmission seizes or experiences unusual wear, comparatively large pieces of wear debris are released. The goal of the use of the apparatus is to detect these particles of wear debris, stop testing before damage occurs, and clarify the causes. Seizure was, therefore, artificially induced in a transmission, and the wear debris in the oil was closely analyzed following the test.

The results showed that when the simulated seizure occurred, large, elongated particles of wear debris were produced. Similar wear debris was observed in oil recovered from the market following the seizure of a component, and at present this is believed to be a type of wear debris characteristic of seizure. By knowing in advance the particle counter that predict danger depending on the component being monitored, it was possible to monitor the state of components by measuring the distribution of particle counter in the oil.
Damped Tailgate System Drop Dynamics and Evaluation of Strut Force for Durability
Authors: Kirtane Vivek , Morley John
Published: April 2020

This paper describes a simplified CAE simulation for the calculation of peak strut force in a damped tailgate system. Tailgate systems in the past included a torsion rod for lift assist, but did not include damping in the opening/drop direction. Newer tailgate systems include a strut to provide damping during drop and possibly lift assist. These tailgates may also be designed to experience a free-fall for a few degrees after being unlatched and before the strut engages. When the latch is released, the tailgate accelerates as it falls freely and then encounters a rapidly increasing damping force as the strut engages. The deceleration of the gate depends upon the damping force, yet the damping force depends upon the deceleration of the tailgate, making a precise calculation of the damping force difficult. Damping characteristics of the strut depend on the volume, the viscosity of oil and its flow restrictions across the piston. These parameters are not known early in the design process.

This study presents a method to back calculate the damping force on a tailgate solely based on the desired drop time, and does not require physical measurements of the strut. An ABAQUS explicit analysis with beams and connectors is defined to simulate the tailgate drop event. The simulation calculates the damping force, based on a linear damping coefficient and the velocity of the strut at each incremental drop position. Peak strut force is found to occur mid-way through the drop event and is greater than the force of the fully compressed strut. The simulation shows good correlation to measured time history for strut force, tailgate drop angle and strut linear motion.
Electric Motor for Brakes – Optimal Design
Authors: Di Gerlando Antonino , Gobbi Massimiliano , Mastinu Giampiero , Miotto Alessio
Published: April 2020

A multi-objective optimal design of a brushless DC electric motor for a brake system application is presented. Fifteen design variables are considered for the definition of the stator and rotor geometry, pole pieces and permanent magnets included. Target performance indices (peak torque, efficiency, rotor mass and inertia) are defined together with design constraints that refer to components stress levels and temperature thresholds, not to be surpassed after heavy duty cycles. The mathematical models used for optimization refer to electromagnetic field and related currents computation, to thermo-fluid dynamic simulation, to local stress and vibration assessment. An Artificial Neural Network model, trained with an iterative procedure, is employed for global approximation purposes. This allows to reduce the number of simulation runs needed to find the optimal configurations. Some of the Pareto-optimal solutions resulting from the optimal design process are analysed. They show high improvements of the performance indices with respect to a reference solution.
Evaluation of High Resistance Connection in Automotive Application
Authors: Modi Manoj , Galgoci Brad
Published: April 2020

Electrical connections have a normal operational temperature range. A high resistance, such as a poor connection, in an electrical circuit has been reported to cause a temperature increase exceeding normal operational range at the connection.

This study measures the temperature increase in a typical automotive bolted battery cable connection with low to zero torque values and simulated high resistance under different load conditions. The torque is changed from maximum design value to 0 Nm and the temperature increase at the connection is measured. The high resistance connections, manually created by adjusting the contacts, are tested for several power loss values at the connection. The temperature rise under these conditions at the connection is measured and subsequently recorded.

The maximum temperature increase at the bolted cable connection recorded at low torque values including 0 Nm torque compared to the maximum typical design value of 17 Nm is 10.5 °C. The maximum temperature increase for the high resistance bolted connection is a function of the power loss and the voltage drop at the connection.
RouteE: A Vehicle Energy Consumption Prediction Engine
Authors: Holden Jacob , Reinicke Nicholas , Cappellucci Jeff
Published: April 2020

The emergence of connected and automated vehicles and smart cities technologies create the opportunity for new mobility modes and routing decision tools, among many others. To achieve maximum mobility and minimum energy consumption, it is critical to understand the energy cost of decisions and optimize accordingly. The Route Energy prediction model (RouteE) enables accurate estimation of energy consumption for a variety of vehicle types over trips or sub-trips where detailed drive cycle data are unavailable. Applications include vehicle route selection, energy accounting and optimization in transportation simulation, and corridor energy analyses, among others. The software is a Python package that includes a variety of pre-trained models from the National Renewable Energy Laboratory (NREL). However, RouteE also enables users to train custom models using their own data sets, making it a robust and valuable tool for both fast calculations and rigorous, data-rich research efforts. The pre-trained RouteE models are established using NREL’s Future Automotive Systems Technology Simulator paired with approximately 1 million miles of drive cycle data from the Transportation Secure Data Center, resulting in energy consumption behavior estimates over a representative sample of driving conditions for the United States. Validations have been performed using on-road fuel consumption data for conventional and electrified vehicle powertrains. Transferring the results of the on-road validation to a larger set of real-world origin-destination pairs, it is estimated that implementing the present methodology in a green-routing application would accurately select the route that consumes the least fuel 90% of the time. The novel machine learning techniques used in RouteE make it a flexible and robust tool for a variety of transportation applications.