bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid Forming - A Novel Manufacturing Technique for Metal-LFT Structural Parts
Authors: Heidrich Daniel , Kloska Tobias , Fang Xiangfan
Published: April 2020

Hybrid structural parts combining aluminum or steel sheets with long glass fiber reinforced thermoplastics (LFT) offer a great opportunity to reduce component weight for automotive applications. But due to high manufacturing cost, metal-LFT hybrid components are still scarcely used in automotive large-scale production. Thus in this work a novel cost- and time efficient manufacturing process for simultaneous metal sheet forming and compression molding of long fiber reinforced thermoplastics to manufacture automotive lightweight components is presented. In this manufacturing process, which is referred to as “Hybrid forming”, a fiber reinforced thermoplastic melt is used as a forming medium in the manner of well-known hydroforming processes. After forming the metal sheet by polymer melt in combination with the rigid die, the melt solidifies and forms a local reinforcement structure in the hybrid component. Since the metal sheet is pre-coated with a bonding agent prior to the forming process, a firmly bonded connection between metal and LFT can be achieved.

For proof of concept a longitudinal control arm in a multi-link rear axle is chosen. By utilizing Hybrid forming a hybrid steel-LFT control arm is manufactured with weight savings of 20 % with regard to the metal reference component. Weight savings are derived by reducing the metal thickness and compensate stiffness and strength with local load-conforming LFT ribs. The metal part of the hybrid control arm guaranties the same positive fail-safe behavior of a metal component in contrast to the brittle failure mechanics of pure CFRP/GFRP components.

To verify the resilience of the hybrid component and especially the bonding surface between steel and LFT quasi-static tests and fatigue tests were conducted. The results are compared with the FE-simulations to validate the simulation technique, which can be used to design metal-LFT structural parts manufactured by hybrid forming for future applications.
A Novel Technique for Measuring Cycle-Resolved Cold Start Emissions Applied to a Gasoline Turbocharged Direct Injection Engine
Authors: Hu Jinghu , Hall Matthew , Matthews Ron , Moilanen Peter , Wooldridge Steven , Yi Jianwen
Published: April 2020

There is keen interest in understanding the origins of engine-out unburned hydrocarbons emitted during SI engine cold start. This is especially true for the first few firing cycles, which can contribute disproportionately to the total emissions measured over standard drive cycles such as the US Federal Test Procedure (FTP). This study reports on the development of a novel methodology for capturing and quantifying unburned hydrocarbon emissions (HC), CO, and CO2 on a cycle-by-cycle basis during an engine cold start. The method was demonstrated by applying it to a 4 cylinder 2 liter GTDI (Gasoline Turbocharged Direct Injection) engine for cold start conditions at an ambient temperature of 22°C. For this technique, the entirety of the engine exhaust gas was captured for a predetermined number of firing cycles. By capturing the exhaust of different numbers of firing cycles, from one to five for example, the emissions contribution of each successive cycle was determined on an ensemble average basis. The development of custom engine control software allowed predetermined event-by event control of individual cylinder fuel injection and spark settings. A dual injection strategy was studied with both an early and a late injection. Emitted masses of HCs (on a C3 propane basis), CO and CO2 were measured for each successive cycle. It was found that the first two firing cycle out of five contributed the most unburned hydrocarbon and CO mass, with emissions decreasing for later cycles. Measured cycle-resolved HC mass decreased monotonically from approximately 35 mg for the first firing cycle to less than 5 mg for the 5th cycle, an inordinately high value potentially due to misfires at the first two firing events. Cycle-resolved CO masses were on the order of approximately 15 mg per cycle. An advantage of the technique is that is not subject to some of the possible sampling issues that may be encountered with the use of a modal approach (i.e., fast FID + mass flow estimation) and allows the cycle-resolved quantification of CO and CO2 mass quantities in addition to HC mass.
Analysis of Performance and Emission of Diesel Engines Operating on Palm Oil Biodiesel
Authors: Bari Saiful , Zhang Chi
Published: April 2020

Fast consumption of fossil fuels is demanding researchers to find few potential alternative fuels that meet sustainable energy demand in the near future with least environmental impact. Future energy system needs to be cost-efficient, renewable, and safe to handle. Biodiesel is expected to be the future energy source that meets all the environmental norms. The use of biodiesel in Internal Combustion (IC) engines represents an alternative clean energy source compared to hydrocarbon fuels that generate emissions such as carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOX), Sulfur Oxides (SO) and particulate matters (PM). This paper describes the importance of Palm Oil Diesel (POD) as an alternative fuel source for diesel engines. Simulations are carried out with ANSYS FORTE software with POD. The engine chosen is a 26-kW diesel-gen-set. The engine geometry is drawn in SOLIDWORKS using dimensions of the actual diesel engine. Then, the geometry is imported in ANSYS FORTE and simulations are carried out with diesel and compared with the experimental data which shows around 97% accuracy. Then, a CHEMKIN file is created to use POD in ANSYS FORTE. Thereafter, simulations are carried out with POD with standard engine settings and compared with diesel. The engine performances are lower with POD due to lower calorific value, higher viscosity, higher density and heavier molecules present in POD. POD has a higher cetane number which is beneficial from the combustion point of view. In-cylinder pressure, temperature and accumulated heat release vs. crank angle are plotted to find out the combustion characteristics of POD and compared with diesel. The liquid and vapor penetration length, droplet size and mass are also plotted and compared with diesel.
Multi-Material Topology Optimization Considering Manufacturing Constraints
Authors: Shah Vishrut , Kashanian Kiarash , Pamwar Manish , Sangha Balbir , Kim Il Yong
Published: April 2020

The field of topology optimization (TO) has been evolving rapidly, notably due to the emergence of multi-material topology optimization (MMTO) algorithms. These developments follow the establishment of TO tools within industry, which has been accelerated and promoted through the introduction of various manufacturing constraints within algorithms. The integration of manufacturing constraints within MMTO is critical for promoting industry usage and adoption of these new software algorithms, as current usage of MMTO is dissuaded by the typically complex design solutions.

The presented MMTO implementation is an extension of classical single-material topology optimization (SMTO). The TO problem is expanded to consider both material existence and selection, solid isotropic material with penalization (SIMP) is utilized for material interpolation. The method of moving asymptotes (MMA) has been integrated into MMTO as the optimization algorithm as it can handle large-scale problems with many design variables.

A design variable mapping system has been incorporated into MMTO, which determines element groups based on symmetry or extrusion manufacturing constraints. The design variables of the group elements are constrained to equivalent values, resulting in either extruded or symmetric MMTO geometry. Several problems, of varying scale and optimization problem statement are solved using MMTO without manufacturing constraints, MMTO with extrusion, and MMTO with symmetry constraints. The optimized geometry and numeric performance are analyzed to determine the feasibility of the manufacturing constraints in reducing computational time and increasing design manufacturability. These benefits are contrasted against the reduction in structural performance; a consequence of reduced design freedom when enforcing manufacturing constraints.
A Zero-Dimensional Velocity-Composition-Frequency Probability Density Function Model for Compression-Ignition Engine Simulation
Authors: Paul Chandan , Jin Kai , Fogla Navin , Roggendorf Kevin , Wahiduzzaman Syed
Published: April 2020

Numerical simulation of in-cylinder processes can significantly reduce the development and refinement costs of engines. While it can be argued that higher fidelity models improve accuracy of prediction, it comes at the expense of high computational cost. In this respect, a 3D analysis of in-cylinder processes may not be feasible for evaluating large number of design and operating conditions. The situation can be more foreboding for transient simulations. In the current work a phenomenological combustion modeling approach is explored that can be implemented in a lower fidelity modeling framework and can approach the accuracy of higher dimensional models with significant reduction in computational cost. The proposed model uses transported probability density function (tPDF) method within a 0D framework to provide a computationally efficient solution while capturing the essential physics of in-cylinder combustion. Scalar mixing is accounted for by a modified Euclidean Minimum Spanning Tree (EMST) mixing model. A new model has been formulated to calculate the mixing timescale using the velocity-composition-frequency (VCF) tPDF method. Numerical comparisons have been performed for two engines: one with a 3D-CFD simulated diesel engine to compare the in-cylinder composition and thermal stratification, and one with a diesel engine where measured data is available over a range of operating conditions encompassing a range of speed, load, and exhaust-gas recirculation (EGR). A 42-species chemical mechanism including thermal NO is used to represent the gas-phase chemistry. The proposed 0D-VCF model predicted pressure, heat-release-rate, equivalence-ratio vs temperature distribution, and NOx are compared to the 3D-CFD data, as well as to the experimentally measured data. The proposed model was able to capture the 3D-CFD trend of equivalence-ratio vs temperature distribution at different crank-angle degrees quite accurately. The 0D-VCF model computed pressure and heat-release-rate along with the NOx showed reasonable agreement with the experiment. In summary, the proposed 0D numerical model has the potential to provide a computationally less expensive alternative to a 3D numerical simulation for estimating engine performance and engine-out emission quantities when transient or large number of operating points are to be simulated.
Investigation of Wave Stripping Models on a Generic Wing-Mirror Using a Coupled Level-Set Volume of Fluid Simulation
Authors: Skarysz Maciej , Garmory Andrew , Escobar Jose , Jilesen Jonathan , Gaylard Adrian
Published: April 2020

Predicting Exterior Water Management is important for developing vehicles that meet customer expectations in adverse weather. Fluid film methods, with Lagrangian tracking, can provide spray and surface water simulations for complex vehicle geometries in on-road conditions. To cope with this complexity and provide practical engineering simulations, such methods rely on empirical sub-models to predict phenomena such as the film stripping from the surface. Experimental data to develop and validate such models is difficult to obtain therefore here a high-fidelity Coupled Level-set Volume of Fluid (CLSVOF) simulation is carried out. CLSVOF resolves the interface of the liquid in three dimensions; allowing direct simulation of film behaviour and interaction with the surrounding air. This is used to simulate a simplified wing-mirror, with air flow, on which water is introduced. The film shows very different behaviour on the in-board section, where a film is developed which eventually breaks to rivulets, and the end of the mirror, where the water is rapidly stripped off the surface due to the higher shear stress from the air. The same case is simulated using a fluid film method, which shows that a simple film stripping model based on film height is not capable of predicting the different regimes observed with CLSVOF. However, a model based on wave stripping due to Kelvin-Helmholtz instability is seen to give good agreement, as was a model based on local film velocity, surface curvature and body force. As well as informing the development of a film stripping model, this also illustrates how a high-fidelity simulation can be used as a tool for developing practical engineering software.
Simulation of Transient On-Road Conditions in a Closed Test Section Wind Tunnel Using a Wing System with Active Flaps
Authors: Wilhelmi Henning , Jessing Christoph , Bell James , Heine Daniela , Wagner Andreas , Wiedemann Jochen , Wagner Claus
Published: April 2020

Typical automotive research in wind tunnels is conducted under idealized, stationary, low turbulence flow conditions. This does not necessarily reflect the actual situation in traffic. Thus, there is a considerable interest to simulate the actual flow conditions. Because of this, a system for the simulation of the turbulence intensity I, the integral linear scale L and the transient angle of incidence β measured in full-scale tests in the inflow of a test vehicle was developed and installed in a closed-loop, closed test section wind tunnel. The system consists of four airfoils with movable flaps and is installed in the beginning of the test section. Time-series of the flow velocity vector are measured in the empty test section to analyze the system’s envelope in terms of the turbulence intensity and the integral length scales. It is shown that the length scales in spanwise and in driving (streamwise) direction can be varied from 0.15 m to 7.9 m and from 0.15 m to 2.5 m, respectively, depending on the frequency of the flap movement. The maximum obtained turbulence intensity in the driving direction x is 3% and in the spanwise direction y 9.8%, depending on the flap’s amplitude. It is further shown that the turbulence intensity in driving direction can be increased to 5.6% with passive turbulence generators. Additionally, a model for predicting the flap movement reproducing the transient angle of incidence β measured in the on-road tests during an overtaking maneuver was developed. Measurements of the forces acting on the vehicle revealed an influence of the non-stationary flow on the non-stationary force coefficients. Finally, changes of up to 0.002 in Δcd and 0.157 in Δcs were measured.
LiDAR Data Segmentation in Off-Road Environment Using Convolutional Neural Networks (CNN)
Authors: Dabbiru Lalitha , Goodin Chris , Scherrer Nicklaus , Carruth Daniel
Published: April 2020

Recent developments in the area of autonomous vehicle navigation have emphasized algorithm development for the characterization of LiDAR 3D point-cloud data. The LiDAR sensor data provides a detailed understanding of the environment surrounding the vehicle for safe navigation. However, LiDAR point cloud datasets need point-level labels which require a significant amount of annotation effort. We present a framework which generates simulated labeled point cloud data. The simulated LiDAR data was generated by a physics-based platform, the Mississippi State University Autonomous Vehicle Simulator (MAVS). In this work, we use the simulation framework and labeled LiDAR data to develop and test algorithms for autonomous ground vehicle off-road navigation. The MAVS framework generates 3D point clouds for off-road environments that include trails and trees. The important first step in off-road autonomous navigation is the accurate segmentation of 3D point cloud data to identify the potential obstacles in the vehicle path. We use simulated LiDAR data to segment and detect obstacles using convolutional neural networks (CNN). Our analysis is based on SqueezeSeg, a CNN-based model for point cloud segmentation. The CNN was trained with a labelled dataset of off-road imagery generated by MAVS and evaluated on the simulated dataset. The segmentation of the LiDAR data is done by point-wise classification and the results show excellent accuracy in identifying different objects and obstacles in the vehicle path. In this paper, we evaluated the segmentation performance at different LiDAR vertical resolutions: the 8-beam and 16-beam. The results showed that there is about 5% increase in accuracy with 16-beam sensors compared with the 8-beam sensors in detecting obstacles and trees. However, the 8-beam LiDAR performance is comparable with the 16-beam sensor in segmenting vegetation, trail-road and ground.
Safety Assurance Concepts for Automated Driving Systems
Authors: Ballingall Stuart , Sarvi Majid , Sweatman Peter
Published: April 2020

Automated driving systems (ADSs) for road vehicles are being developed that can perform the entire dynamic driving task without a human driver in the loop. However, current regulatory frameworks for assuring vehicle safety may restrict the deployment of ADSs that can use machine learning to modify their functionality while in service. A review was undertaken to identify and assess key initiatives and research relevant to the safety assurance of adaptive safety-critical systems that use machine learning, and to highlight assurance concepts that could benefit from further research. The primary objective was to produce findings and recommendations that can inform policy and regulatory reform relating to ADS safety assurance. Due to the almost infinite number and combination of scenarios that an ADS could encounter, the review found much support for concepts that involve the use of simulation data as virtual evidence of safety compliance, with suggestions of a need to assure simulation tools and models. Real-world behavioural competency testing was also commonly proposed, although noting this concept has its limitations. The concept of whole-of-life assurance was identified, supported by various versions of dynamic runtime monitoring, verification and validation. Concerns regarding Artificial Intelligence (AI) robustness were raised, particularly regarding adversarial inputs and unmodelled scenarios that are essentially unknown unknowns. Further, the concept of explainable AI was highlighted as having potential to provide evidence from an ADS that could support safety assurance and regulatory compliance. While each of the identified assurance concepts should be considered when developing ADS safety assurance framework options, it is recommended that further research on each concept should be progressed.
Bridging the Gap between ISO 26262 and Machine Learning: A Survey of Techniques for Developing Confidence in Machine Learning Systems
Authors: Serna Jose , Diemert Simon , Millet Laure , Debouk Rami , S Ramesh , Joyce Jeffrey
Published: April 2020

Machine Learning (ML) based technologies are increasingly being used to fulfill safety-critical functions in autonomous and advanced driver assistance systems (ADAS). This change has been spurred by recent developments in ML and Artificial Intelligence techniques as well as rapid growth of computing power. However, demonstrating that ML-based systems achieve the necessary level of safety integrity remains a challenge. Current research and development work focused on establishing safe operation of ML-based systems presents individual techniques that might be used to gain confidence in these systems. As a result, there is minimal guidance for supporting a safety standard such as ISO 26262 - Road Vehicles - Functional Safety, to enable the development of ML-based systems. This paper presents a survey of recent ML literature to identify techniques and methods that can contribute to meeting ISO 26262 requirements. The surveyed literature is mapped onto the system development lifecycle V-model and the applicability of individual techniques and methods are discussed for each major phase of development.
Establishing Thermal Stability in an Optically-Accessible CIDI Engine
Authors: Groendyk Michael , Rothamer David
Published: April 2020

Optically-accessible engines are a key tool for the study of sprays, mixing, and ignition and combustion phenomena in internal combustion (IC) engines. Due to their construction, they are typically operated for limited durations, resulting in significant thermal transients in the in-cylinder surface temperatures and cycle-to-cycle in-cylinder gas temperature. This makes collection of highly repeatable data difficult and can introduce considerable uncertainty in the in-cylinder thermal conditions. In this paper, rigorous analyses of transient in-cylinder boundary conditions and in-cylinder gas temperature were performed in an optically-accessible compression-ignition engine. Piston surface thermometry, in-cylinder pressure measurements, and in-cylinder gas thermometry were employed to determine the engine warmup time required to reach a quasi-steady thermal state for motored operation over a range of intake air temperatures and pressures from 300-420 K and 100-300 kPa, respectively. The effect of fueling on thermal stability was investigated for single-injection mixing-controlled compression-ignition combustion utilizing a range of skip-fire ratios from 5:1 to 50:1 and loads from 0.8 to 10.1 bar gross indicated mean effective pressure. Both optical and metal pistons were studied. A motored warmup time of 300 s was found to be sufficient for the engine to reach a thermally stable condition regardless of piston material or intake condition. Piston temperature was found to increase with load, but the increase was modest for even the highest load studied (~4 K) for 10 injection sets typical of late direct-injection optical engine studies.
Battery Entropic Heating Coefficient Testing and Use in Cell-Level Loss Modeling for Extreme Fast Charging
Authors: Lempert Jeremy , Kollmeyer Phillip , Malysz Pawel , Gross Oliver , Cotton James , Emadi Ali
Published: April 2020

To achieve an accurate estimate of losses in a battery it is necessary to consider the reversible entropic losses, which may constitute over 20% of the peak total loss. In this work, a procedure for experimentally determining the entropic heating coefficient of a lithium-ion battery cell is developed. The entropic heating coefficient is the rate of change of the cell’s open-circuit voltage (OCV) with respect to temperature; it is a function of state-of-charge (SOC) and temperature and is often expressed in mV/K. The reversible losses inside the cell are a function of the current, the temperature, and the entropic heating coefficient, which itself is dependent on the cell chemistry. The total cell losses are the sum of the reversible and irreversible losses, where the irreversible losses consist of ohmic losses in the electrodes, ion transport losses, and other irreversible chemical reactions. The entropic heating coefficient is determined by exposing the cell to a range of temperatures at each SOC value of interest. The OCV is recorded at each combination of SOC and temperature, and ∂OCV/∂T is calculated from the measurements. Since a ∆T of 20°C may result in a ∆OCV of 100μV or less, it is critical to have a high accuracy and high input impedance voltage sensor. Additionally, the measurement is sensitive to self-discharge of the battery and the amount of time at each test point. A test methodology is proposed which achieves an accurate OCV measurement, corrects for self-discharge, and utilizes the minimum necessary soak time. Once determined experimentally, the entropic heating coefficient map is used to model losses during several charges with rates from 1C to 5C, and the results are compared with a constant current loss model derived from experimental data for a lithium nickel manganese cobalt oxide (NMC) cell.
Acceleration of Left Turning Heavy Trucks
Authors: Danaher David , Donaldson Andrew , McDonough Sean
Published: April 2020

Accidents involving heavy trucks turning left across travel lanes of a roadway are common subjects of investigation in the field of accident reconstruction. The distance traversed during a turn and lateral and tangential accelerations of the left turning heavy truck can be used to model its motion and determine timing as it relates to a collision. As a follow up to the 2019 SAE Accident Reconstruction section paper by the authors (2019-01-0411), this paper will investigate the longitudinal and lateral accelerations of heavy trucks during small, medium, and large radius turns and analyze peak and average lateral accelerations as they relate to turn radius and vehicle speeds. This study analyzed 70 tractor-trailers, 19 straight trucks and 15 bobtail tractors for a total of 104 heavy trucks. The tractor-trailers had various trailer configurations ranging from flat bed, box and tanker, while the straight trucks are defined as non-articulated heavy trucks with various body configurations such as box, garbage, and cement trucks.
Acoustic Characteristics Prediction and Optimization of Wheel Resonators with Arbitrary Section
Authors: Guo Rong , Mi Tiantian , Sun Yimin , Mao Junlei
Published: April 2020

Tire cavity noise of pure electric vehicles is particularly prominent due to the absence of engine noise, which are usually eliminated by adding Helmholtz resonators with arbitrary transversal section to the wheel rims. This paper provides theoretical basis for accurately predicting and effectively improving acoustic performance of wheel resonators. A hybrid finite element method is developed to extract the transversal wavenumbers and eigenvectors, and the mode-matching scheme is employed to determine the transmission loss of the Helmholtz resonator. Based on the accuracy validation of this method, the matching design of the wheel resonators and the optimization method of tire cavity noise are studied. The identification method of the tire cavity resonance frequency is developed through the acoustic modal test. A scientific transmission loss target curve and fitness function are defined according to the noise characteristics. Combing the transmission loss prediction theory and particle swarm algorithm, the structural parameters of the wheel resonator are optimized. A remarkable attenuation of tire cavity resonance can be observed through test results.
Investigation of Homogeneous Lean SI Combustion in High Load Operating Conditions
Authors: Clasen Kristoffer H. , Koopmans Lucien
Published: April 2020

Homogeneous lean combustion (HLC) can be utilized to substantially improve spark ignited (SI) internal combustion engine efficiency. Higher efficiency is vital to enable clean, efficient and affordable propulsion for the next generation light duty vehicles. More research is needed to ensure robustness, fuel efficiency/NOx trade-off and utilization of HLC. Utilization can be improved by expanding the HLC operating window to higher engine torque domains which increases impact on real driving. The authors have earlier assessed boosted HLC operation in a downsized two-litre engine, but it was found that HLC operation could not be achieved above 15 bar NMEP due to instability and knocking combustion. The observation led to the conclusion that there exists a lean load limit. Therefore, further experiments have been conducted in a single cylinder research DISI engine to increase understanding of high load lean operation. HLC is known to suppress end-gas autoignition (knock) by decreasing reactivity and temperatures, but during the experiments knock was observed to be prominent and increasing in severity when engine load was increased despite operating ultra-lean close to lambda 2. Knock is normally mitigated by spark retardation which decreases peak cylinder pressure. However, to maintain stable combustion at lambda = 2 the combustion phasing had to be kept close to TC which resulted in high peak cylinder pressures. Therefore, the combustion event had to be balanced in a window where early combustion promoted knock and late resulted in instability and partial burns. A tumble flap was introduced to increase in-cylinder tumble which reduced knock and improved combustion stability. It could be observed that for most load-points assessed; increased tumble could suppress knock and increase the air-dilution limit which proved beneficial in decreasing the NOx emissions. The highest engine load that could be achieved with highly diluted combustion was 16 bar NMEP.
NHTSA’s 2018 Heavy Vehicle Automatic Emergency Braking Test Track Research Results
Authors: Salaani M. Kamel , Elsasser Devin , Boday Christopher
Published: April 2020

This paper presents National Highway Traffic Safety Administration’s 2017 and 2018 test track research results with heavy vehicles equipped with forward collision warning and automatic emergency braking systems. Newly developed objective test procedures were used to perform and collect performance data with three single-unit trucks equipped with the crash avoidance systems. The results of this research show that the test procedures are applicable to many heavy vehicles and indicate that performance improvements in heavy vehicles equipped with these safety systems can be objectively measured.
Large Scale Multi-Disciplinary Optimization and Long-Term Drive Cycle Simulation
Authors: Malinovskiy Mark , Hermetet Andrew , Kaushik Shailendra , Lee Christopher
Published: April 2020

Market demands for increased fuel economy and reduced emissions are placing higher aerodynamic and thermal analysis demands on vehicle designers and engineers. These analyses are usually carried out by different engineering groups in different parts of the design cycle. Design changes required to improve vehicle aerodynamics often come at the price of part thermal performance and vice versa. These design changes are frequently a fix for performance issues at a single performance point such as peak power, peak torque, or highway cruise. In this paper, the motivation for a holistic approach in the form of multi-disciplinary optimization (MDO) early in the design process is presented. Using a Response-surface Informed Transient Thermal Model (RITThM) a vehicle's thermal performance through a drive cycle is predicted and correlated to physical testing for validation. Furthermore, an MDO using RITThM is demonstrated with tradeoffs and important trends identified and described along with optimal design points. Potential sources of error, areas for improvement, and potential applications of an MDO using RITThM are presented.
Portable In-Cylinder Pressure Measurement and Signal Processing System for Real-Time Combustion Analysis and Engine Control
Authors: Luo Yilun , Maldonado Bryan , Liu Siying , Solbrig Charles , Adair Devon , Stefanopoulou Anna
Published: April 2020

This paper presents an in-cylinder pressure measurement system for cycle-to-cycle feedback combustion control purposes. Such a system uses off-the-shelf components to measure cylinder pressure and performs user-defined algorithms for heat release analysis. The working principle of the device is discussed as well as the simplifications for heat release analysis required for fast computation. The system is benchmarked against a commercially-available combustion analyzer in order to quantify the accuracy and time response. The results showed that the system is satisfactorily accurate for combustion phasing control. The main advantage, however, comes from the reduction of calculation and communication delays observed in the commercially-available system. This enables the use of cycle-to-cycle cylinder pressure-based feedback control algorithms. The functionality of such a device is demonstrated in a spark-ignition experimental engine fitted with an externally cooled exhaust gas recirculation (EGR) loop. Here, an optimal combustion phasing was the target for a feedback combustion controller that automatically adjusted the spark advance. The favorable results proved the system suitable not only for this particular combustion control problem with EGR but also for many of the modern combustion control strategies in gasoline and diesel engines.
The Use of Piezoelectric Washers for Feedback Combustion Control
Authors: Corti Enrico , Abbondanza Marco , Ponti Fabrizio , Raggini Lorenzo
Published: April 2020

The use of piezoelectric cylinder pressure sensors is very popular during engine testing, but cylinder pressure information is becoming mandatory also in several on-board applications, where Low Temperature Combustion (LTC) approaches require a feedback control of combustion, due to poor combustion stability and the risk of knock or misfire.

Several manufacturers showed the capability to develop solutions for cylinder pressure sensing in on-board automotive and aeronautical applications, and some of them have been patented. The most straight-forward approach seems the application of a piezo-electric washer as a replacement of the original part equipping the spark plug; the injector could also be used to transfer the cylinder pressure information to the piezoelectric quartz, in diesel or Gasoline Direct Injections (GDI) engines.

The paper describes the features of signals acquired using piezoelectric washers, discussing possible applications, highlighting the factors which impact the sensors accuracy, and proposing algorithms to compensate potential errors in the evaluation of combustion metrics. The sensors have been first tested on a press, then in two different gasoline engines: a naturally aspirated V12 and a turbocharged 2 cylinders with Variable Valve Lift system (VVL). Signals have been compared to those obtained with lab-grade cylinder pressure sensors, with particular attention to peak pressure, combustion phase and knock intensity.

The main issue affecting the accuracy of cylinder pressure measurement using the piezoelectric spark plug washer is the effect of temperature variations both on the force transmitted by the thread to the washer and piezoelectricity properties.
Control Model of Automated Driving Systems Based on SOTIF Evaluation
Authors: Guo Mengge , Shang Shiliang , Haifeng Cui , Zhang Kaijiong , Deng Weishun , Zhang Xi , Yu Fan
Published: April 2020

In partially automated and conditionally automated vehicles, a part of the work of human drivers is replaced by the system, and the main source of safety risks is no longer system failures, but non-failure risks caused by insufficient system function design. The absence of unreasonable risk due to hazards resulting from functional insufficiencies of the intended functionality or by reasonably foreseeable misuse by persons, is referred to as the Safety Of The Intended Functionality. Drivers have the responsibility to supervise the automated driving system. When they don't agree with the operation behavior of the system, they will interfere with the instructions. However, this may lead to potential risks. In order to discover the causes of human misuse, this paper takes the trust feeling between the driver and the automated driving system as the starting point, and based on the collected data of track test, establishes the evaluation indicator -- degree of confidence to show the trust feeling between the driver and the automated system. Degree of confidence is a comprehensive interpretation of the driver's physical and psychological feelings. In the process of track test, we simultaneously collect the dynamics indicators of the vehicle. After the test, the drivers' driving feeling was evaluated by questionnaire. Then, the relationship between objective indicator and subjective score was established by machine learning method, and the development of evaluation indicator was completed. Finally, this paper optimizes the automatic driving motion planning algorithm based on this indicator, and verifies the effectiveness of the algorithm through simulation.
In-Vehicle Diagnostic System for Prognostics and OTA Updates of Automated/Autonomous Vehicles
Authors: Subke Peter , Moshref Muzafar , Erber Julian
Published: April 2020

The increasing complexity of microcontroller-based automotive E/E systems that control road-vehicles and non-road mobile machinery comes with increased self-diagnosis functions and diagnosability via external test equipment (diagnostic tester).

Technicians in the development, production and service depend on diagnostic test equipment that is connected to the E/E system and performs diagnostic communication. Examples of use cases of diagnostic communication include but are not limited to condition monitoring, data acquisition, (guided) fault finding and flash programming.

More and more functions of a modern vehicle are realized by software (firmware). Powerful multicore servers replace the numerous control units and many control unit functions can be performed directly by smart sensors and actuators.

New E/E system architectures come with increased self-diagnostic capabilities. They automatically perform tests, log diagnostic data and push such data for prognostics purposes and condition (health) monitoring to the cloud. They also support over-the-air firmware updates (FOTA).

This paper describes the components of an E/E system that is equipped with an in-vehicle diagnostic tester. The tester consists of standardized components, including MVCI-Server (ISO 22900), ODX (ISO 22901), OTX (ISO 13209) and UDS on IP (ISO 14229-5). The paper includes a description of cybersecurity measures to protect the vehicle against malicious attacks.
De impact van flexibele arbeids-contracten op de vitaliteit en productiviteit van de flexwerkers
Authors: Hosseini Ziagul , Koopmans Linda , Verbiest Sarike
Published: April 2020

Het aantal werknemers met een flexibel contract neemt toe. De vraag die dit artikel behandelt is hoe verschillende typen flexibele contracten en baanonzekerheid verband houden met vitaliteit en productiviteit in vergelijking met een vast contract. De uitkomsten van deze studie laten zien dat werknemers met een tijdelijk contract zonder uitzicht op vast en uitzendkrachten lager scoren op vitaliteit dan vaste werknemers, vanwege hun hogere baanonzekerheid. Werknemers met een tijdelijk contract zonder uitzicht op vast, uitzend- en oproepkrachten scoren lager op productiviteit dan vaste werknemers, (deels) door hun hogere baanonzekerheid. HR-professionals kunnen een rol spelen om de positie van flexwerkers op de arbeidsmarkt te versterken.The number of employees with a flexible contract is increasing. The aim of this study was to investigate how types of flexible contracts and job insecurity were related to vitality and productivity in comparison to permanent contract. Longitudinal analyses were used to study whether the change of contract influences vitality and productivity over time. Cross-sectional analyses were used to investigate the relationship between vitality, productivity, and job insecurity. The data were derived from the ‘Cohort Study on Sustainable Employability’ (CODI) from TNO. 15,185 participants in 2016 and 9,698 in 2017 from 15 to 74 years old were included in this study. Employees with a fixed period and agency contract have lower vitality because their job insecurity was higher. Employees with a fixed period, agency and on-call contract have lower productivity than permanent employees (partly) because their job insecurity was higher. HR professionals can play a role in order to strengthen the position of flex workers in the labour market.
Laboratory studies of fresh and aged biomass burning aerosols emitted from east African biomass fuels – Part 2: Chemical properties and characterization
Authors: Smith Damon M. , Cui Tianqu , Fiddler Marc N. , Pokhrel Rudra , Surratt Jason D. , Bililign Solomon
Published: April 2020

Abstract. There are many fuels used for domestic purposes in east Africa, producing a significant atmospheric burden of the resulting aerosols, which includes biomass burning particles. However, the aerosol physicochemical properties are poorly understood. Here, combustion of Eucalyptus and Acacia fuels was performed at 500 and 800 °C in a tube furnace, followed by immediate filter collection for fresh samples or introduction into a photochemical chamber to simulate atmospheric photochemical aging under the influence of anthropogenic emissions. The aerosol generated in the latter experiment was collected onto filters after 12 hours of photochemical aging. 500 and 800 °C were selected to simulate smoldering and flaming combustion, respectively, and to cover a range of combustion conditions. Methanol extracts from Teflon filters were analyzed by ultra-performance liquid chromatography interfaced to both a diode array detector and an electrospray ionization high-resolution quadrupole time-of-flight mass spectrometer (UPLC/DAD-ESI-HR-QTOFMS) to determine the light-absorption properties of biomass burning organic aerosol constituents chemically characterized at the molecular level. Few chemical or UV/Visible differences were apparent between samples for either fuel when combusted at 800 °C. Differences in single scattering albedo (SSA) between fresh samples at this temperature were attributed to compounds not captured in this analysis, with eucalyptol being one suspected missing component. For fresh combustion at 500 °C, many species were present, where lignin pyrolysis and distillation products are more prevalent in Eucalyptus, while pyrolysis products of cellulose and at least one nitroaromatic species were more prevalent in Acacia. SSA trends are consistent with this, particularly if the absorption of those chromophores extends to the 500–570 nm region. Upon aging, both show that resorcinol or catechol was removed to the highest degree, and both aerosol types were dominated by loss of pyrolysis and distillation products, though both differed in the specific compounds being consumed by the photochemical aging process.
Remote sensing of methane leakage from natural gas and petroleum systems revisited
Authors: Schneising Oliver , Buchwitz Michael , Reuter Maximilian , Vanselow Steffen , Bovensmann Heinrich , Burrows John P.
Published: April 2020

Abstract. The switch from the use of coal to natural gas or oil for the energy generation potentially reduces the greenhouse gas emissions and thus the impact on global warming and climate change because of the larger energy content per CO2 molecule emitted. However, the climate benefit over coal is offset by methane (CH4) leakage from natural gas and petroleum systems, which reverses the climate impact mitigation if the rate of fugitive emissions exceeds the compensation point at which the global warming resulting from the leakage and the benefit from the reduction of coal combustion coincide. Consequently, an accurate quantification of the CH4 emissions from the oil and gas industry is essential to evaluate the suitability of natural gas and petroleum as bridging fuels on the way to a carbon-neutral future. We show that regional CH4 release from large oil and gas fields can be monitored from space by using dense daily recurrent measurements of the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite to quantify emissions and leakage rates. The average emissions for the time period 2018/2019 from the five most productive basins in the United States, the Permian, Appalachia, Eagle Ford, Bakken, and Anadarko are estimated to be 3.16 ± 1.13 Mt yr−1, 2.36 ± 0.88 Mt yr−1, 1.52 ± 0.68 Mt yr−1, 0.89 ± 0.56 Mt yr−1, and 2.81 ± 0.77 Mt yr−1, respectively. This corresponds to CH4 leakage rates relative to the associated production between 1.2 % and 1.6 % for the first four production regions, which are consistent with bottom-up estimates and likely fall below the break-even leakage rate for immediate climate benefit. For the Anadarko Basin, the fugitive emission rate is larger and amounts to 4.0 ± 1.1 %, which likely exceeds the break-even rate for immediate benefit and roughly corresponds to the break-even rate for a 20-year time horizon. The determined values are smaller than previously derived satellite-based leakage rates for the time period 2009–2011, which was an early phase of hydraulic fracturing, indicating that it is possible to improve the climate footprint of the oil and gas industry by adopting new technologies and that the efforts to reduce the methane emissions have been successful. For two of the world's largest natural gas fields Galkynysh and Dauletabad in Turkmenistan, we find collective methane emissions of 3.23 ± 1.17 Mt yr−1, which corresponds to a leakage rate of 4.1 ± 1.5 % suggesting that the Turkmen energy industry has not the technological standards concerning avoidance of emissions than the United States average. Together with the high leakage rate for the Anadarko Basin, this indicates that there is potential to reduce fugitive methane emissions from natural gas and petroleum systems worldwide. In particular, relatively newly developed oil and gas plays appear to have larger leakage rates in contrast to more mature production areas.
Photooxidation of pinonaldehyde at ambient conditions investigated in the atmospheric simulation chamber SAPHIR
Authors: Rolletter Michael , Blocquet Marion , Kaminski Martin , Bohn Birger , Dorn Hans-Peter , Hofzumahaus Andreas , Holland Frank , Li Xin , Rohrer Franz , Tillmann Ralf , Wegener Robert , Kiendler-Scharr Astrid , Wahner Andreas , Fuchs Hendrik
Published: April 2020

Abstract. The photooxidation of pinonaldehyde, one product of the α-pinene degradation, was investigated in the atmospheric simulation chamber SAPHIR under natural sunlight at low NO concentrations (
The impact of ship emissions on air quality and human health in the Gothenburg area – Part II: Scenarios for 2040
Authors: Ramacher Martin O. P. , Tang Lin , Moldanová Jana , Matthias Volker , Karl Matthias , Fridell Erik , Johansson Lasse
Published: April 2020

Abstract. Shipping is an important source of air pollutants, from the global to the local scale. Ships are emitting substantial amounts of sulphur dioxides, nitrogen dioxides and particulate matter in the vicinity of coasts, threatening the health of the coastal population, especially in harbour cities. Reductions of emissions due to shipping have been targeted by several regulations. Nevertheless, effects of these regulations come into force with temporal delays, global ship traffic is expected to grow in the future, and other land-based anthropogenic emissions might decrease. Thus, it is necessary to investigate combined impacts to identify the impact of shipping activities on air quality, population exposure and health-effects in the future. We investigated the future effect of shipping emissions on air quality and related health effects considering different scenarios of the development of shipping under current regional trends of economic growth and already decided regulations in the Gothenburg urban area in 2040. Additionally, we investigated the impact of a large-scale implementation of shore electricity in the port of Gothenburg. For this purpose, we established a one-way nested chemistry transport modelling (CTM) system from the global to the urban scale, to calculate pollutant concentrations, population weighted concentrations and health-effects related to NO2, PM2.5 and O3. The simulated concentrations of NO2 and PM2.5 in future scenarios for the year 2040 are in general very low with up to 4 ppb for NO2 and up to 3.5 µg/m3 PM2.5 in the urban areas which are not close to the port area. From 2012 the simulated overall exposure to PM2.5 decreased by approximately 30 % in simulated future scenarios, for NO2 the decrease was over 60 %. The simulated concentrations of O3 increased from year 2012 to 2040 by about 20 %. In general, the contributions of local shipping emissions in 2040 focus on the harbour area but to some extent also influence the rest of the city domain. The simulated impact of wide use of shore-site electricity for shipping in 2040 shows reductions for NO2 in the port with up to 30 %, while increasing O3 of up to 3 %. Implementation of on-shore electricity for ships at berth leads to additional local reduction potentials of up to 3 % for PM2.5 and 12 % for SO2 in the port area. All future scenarios show substantial decreases in population weighted exposure and health-effect impacts.