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Viewing 1 to 30 of 5194
2017-11-02
Magazine
700 miles, hands-free! GM's Super Cruise turns Cadillac drivers into passengers in a well-engineered first step toward greater vehicle autonomy. Toyota rethinks the Flagship The 2018 Lexus LS moves to twin-turbo V6 power and piles on the takumi. Honda 2018 Accord: Antidote for crossover fever The all-new, tenth-generation Accord is Honda's best-ever-and makes the case for why crossovers shouldn't take over the planet. Autonomy testing: Simulation to the rescue Autonomous technology development injects new rigors on vehicle-development testing.
2017-10-08
Technical Paper
2017-01-2186
Lukas Urban, Michael Grill, Sebastian Hann, Michael Bargende
Abstract Engine Knock is a stochastic phenomenon that occurs during the regular combustion of spark ignition (SI) engines and limits its efficiency. Knock is triggered by an autoignition of local “hot spots” in the unburned zone, ahead of the flame front. Regarding chemical kinetics, the temperature and pressure history as well as the knock resistance of the fuel are the main driver for the autoignition process. In this paper, a new knock modeling approach for natural gas blends is presented. It is based on a kinetic fit for the ignition delay times that has been derived from chemical kinetics simulations. The knock model is coupled with an enhanced burn rate model that was modified for Methane-based fuels. The two newly developed models are incorporated in a predictive 0D/1D simulation tool that provides a cost-effective method for the development of natural gas powered SI engines.
2017-10-08
Technical Paper
2017-01-2194
Mateusz Pucilowski, Mehdi Jangi, Sam Shamun, Martin Tuner, Xue-Song Bai
Abstract Heavy-duty direct injection compression ignition (DICI) engine running on methanol is studied at a high compression ratio (CR) of 27. The fuel is injected with a common-rail injector close to the top-dead-center (TDC) with two injection pressures of 800 bar and 1600 bar. Numerical simulations using Reynold Averaged Navier Stokes (RANS), Lagrangian Particle Tracking (LPT), and Well-Stirred-Reactor (WSR) models are employed to investigate local conditions of injection and combustion process to identify the mechanism behind the trend of increasing nitrogen oxides (NOx) emissions at higher injection pressures found in the experiments. It is shown that the numerical simulations successfully replicate the change of ignition delay time and capture variation of NOx emissions.
2017-10-08
Technical Paper
2017-01-2202
Shiyou Yang
Abstract This work presents an application of two sub-models relative to chemical-kinetics-based turbulent pre-mixed combustion modeling approach on the simulation of burn rate and emissions of spark ignition engines. In present paper, the justification of turbulent pre-mixed combustion modeling directly based on chemical kinetics plus a turbulence model is given briefly. Two sub-models relative to this kind of pre-mixed combustion modeling approach are described generally, including a practical PRF (primary reference fuel) chemical kinetic mechanism which can correctly capture the laminar flame speed under a wide range of Ford SI (spark ignition) engines/operating conditions, and an advanced spark plug ignition model which has been developed by Ford recently.
2017-10-08
Technical Paper
2017-01-2280
Yuzuru Nada, So Morimoto, Yoshiyuki Kidoguchi, Ryu Kaya, Hideaki Nakano, Shinichi Kobayashi
Abstract The aim of this study is to clarify the mixture formation in the combustion chamber of our developed natural gas engine incorporating the sub-chamber injection system, in which natural gas is directly injected into a combustion sub-chamber in order to completely separate rich mixture in the sub-chamber, suitable for ignition, from ultra-lean mixture in the main chamber. Mixture distributions in chambers with and without sub-chamber were numerically simulated at a variety of operating conditions. The commercial software of Fluent 16.0 was used to conduct simulations based on Reynolds averaged Navier-Stokes equations in an axial 2 dimensional numerical domain considering movements of piston. Non-reactive flow in the combustion chamber was simulated before the ignition timing at an engine speed of 2000 rpm. The turbulence model employed here is standard k-ε model. Air-fuel ratio is set with a lean condition of 30.
2017-10-08
Technical Paper
2017-01-2284
Haifei Zheng
Abstract The potential benefits of reheat burner placed between turbine stages for propulsion system have been recognized for nearly a century. Compared to the conventional non-reheat engines, the turbine inter-guide-vane burner (TIB) engines by using jet-swirl flow scheme (high-G loading) are shown to have a higher specific thrust with no or only small increase in thrust specific fuel consumption. But, it is a known fact that the G loading in the circumferential cavity is inversely proportional to the radius of the circumferential cavity. If one needs to scale this configuration for a larger spool of turbine components, the effeciency of the high G operation and obtained benefits on flame speed will reduce and hence the performance will de-grade.
2017-10-08
Technical Paper
2017-01-2310
Xiaoyan Jia, Baigang Sun, Dongwei Wu, Dan Xu, Wei Zang, Wei Shang, Jie Wang
Abstract The control valve is the most important implementation part of a high pressure common rail system, and its flow characteristics have a great influence on the performance of an injector. In this paper, based on the structure and the working principle of an electromagnetic injector in a high pressure common rail system, a simulation model of the injector is established by AMESim software. Some key parameters of the control valve, including the volume of the control chamber, the diameter of the orifice Z (feeding orifice), the diameter of the orifice A (discharge orifice) and the hole diameter of the fuel diffusion hole are studied by using this model. The results show that these key structural parameters of the control valve have a great influence on the establishment of the control chamber pressure and the action of the needle valve.
2017-09-28
Magazine
Using Thermal Simulation to Model the Effects of Wind on the Mars Curiosity Rover Quality and Validation of Digital Designs for Aerospace and Defense Scaling LiDAR Optical Payloads from Drones to Miniature UAVs Using Sintered Fiber Metal Composites for Aircraft Acoustic Attenuation GaN Breaks Barriers RF Power Amplifiers Go Wide and High Test System Ensures Flawless Performance of Military RF Devices The Impact of Video Compression on Remote Cardiac Pulse Measurement Using Imaging Photoplethysmography Remote physiological measurement technique leverages digital cameras to recover the blood volume pulse from the human body. Sensitivity Simulation of Compressed Sensing Based Electronic Warfare Receiver Using Orthogonal Matching Pursuit Algorithm Calculate the sensitivity of a CS based EW receiver using two modulation schemes.
2017-09-27
Event
The future of Aerospace Operations modeling and simulation requires the development of new technologies and concepts, and the capability to integrate complex systems to satisfy the needs of future aerospace operations. Presentations are solicited in Aerospace Modeling and Simulation. These sessions will provide a forum for international discussion and information on leading-edge research and development associated with insights of future concept elements and technologies in aerospace operations.
2017-09-27
Event
The future of Aerospace Operations modeling and simulation requires the development of new technologies and concepts, and the capability to integrate complex systems to satisfy the needs of future aerospace operations. Presentations are solicited in Aerospace Modeling and Simulation. These sessions will provide a forum for international discussion and information on leading-edge research and development associated with insights of future concept elements and technologies in aerospace operations.
2017-09-23
Technical Paper
2017-01-1952
ChengJun Ma, Fang Li, Chenglin Liao, Lifang Wang
Abstract With the load of urban traffic system becomes more serious, the Automatic Parking System (APS) plays an important role in alleviating the burden of drivers and improving vehicle safety. The APS is consisted of environmental perception, path planning and path following. The path following controls the lateral movement of vehicle during the parking process, and requires the trajectory tracking error to be as small as possible. At present, some control algorithms are used including PID control, pure pursuit control, etc. However, these algorithms relying heavily on parameters and environment, have some problems such as slow response and low precision. To solve this problem, a path following control method based on Model Predictive Control (MPC) algorithm is proposed in this paper. Firstly, Kinematic vehicle model and path tracker based on MPC algorithm are built. Secondly, a test bench that composed of CANoe hardware in the loop (HIL) system and steering wheel system is built.
2017-09-19
Technical Paper
2017-01-2022
Katherine Loundy, Louis Schaefer, Andrew Foran, Catherine Ninah, Khristopher Bandong, Robert Brown, Hunter Heston, John-Paul Steed, William Young, Mark Heinrich, Luis Rabelo
Abstract The future of human exploration in the solar system is contingent on the ability to exploit resources in-situ to produce mission consumables. Specifically, it has become clear that the success of a manned mission to Mars will likely depend on fuel components created on the Martian surface. While several architectures for an unmanned fuel production surface facility on Mars exist in theory, a simulation of the performance and operation of these architectures has not been created. In this paper, the framework describing a simulation of one such architecture is defined. Within this architecture, each component of the base is implemented as a state machine, with the ability to communicate with other base elements as well as a supervisor. An environment supervisor is also created which governs low level aspects of the simulation such as movement and resource distribution, in addition to higher-level aspects such as location selection with respect to operations specific behavior.
2017-09-19
Technical Paper
2017-01-2025
Eugenio Rodriguez
Abstract One of the most important activities associated with the Aerospace or Defense industry is maintenance. Maintainability procedures have a direct impact on safety and operational availability of systems. The processes and procedures that are used during maintenance activities, whether removing and replacing a component of a system, or conducting troubleshooting, are generally discrete by design, and in most cases, a maintainer, or a field service representative (FSR), will follow a sequence of steps as part of a maintenance work package or work instruction to complete the necessary tasks. Depending on the system, those maintenance activities could be complex, requiring a large maintenance window and the availability of resources to ensure completion.
CURRENT
2017-09-19
Standard
AIR902A
This document describes a practical system for a user to determine observer-to-aircraft distances. These observer-to-aircraft distances can be either closest point of approach (CPA) distances during field measurements or overhead distances during acoustic certification tests. The system uses a digital camera to record an image of the subject aircraft. A method of using commercial software to obtain the distance from such an image is presented. Potential issues which may affect accuracy are discussed.
2017-09-19
Journal Article
2017-01-2018
Won Il Jung, Larry Lowe, Luis Rabelo, Gene Lee, Ojeong Kwon
Abstract Operator training using a weapon in a real-world environment is risky, expensive, time-consuming, and restricted to the given environment. In addition, governments are under intense scrutiny to provide security, yet they must also strive for efficiency and reduce spending. In other words, they must do more with less. Virtual simulation, is usually employed to solve these limitations. As the operator is trained to maximize weapon effectiveness, the effectiveness-focused training can be completed in an economical manner. Unfortunately, the training is completed in limited scenarios without objective levels of training factors for an individual operator to optimize the weapon effectiveness. Thus, the training will not be effective. For overcoming this problem, we suggest a methodology on guiding effectiveness-focused training of the weapon operator through usability assessments, big data, and Virtual and Constructive (VC) simulations.
2017-09-19
Journal Article
2017-01-2024
Natasha L. Schatzman, Narayanan Komerath, Ethan A. Romander
Abstract The blade crossing event of a coaxial counter-rotating rotor is a potential source of noise and impulsive blade loads. Blade crossings occur many times during each rotor revolution. In previous research by the authors, this phenomenon was analyzed by simulating two airfoils passing each other at specified speeds and vertical separation distances, using the compressible Navier-Stokes solver OVERFLOW. The simulations explored mutual aerodynamic interactions associated with thickness, circulation, and compressibility effects. Results revealed the complex nature of the aerodynamic impulses generated by upper/lower airfoil interactions. In this paper, the coaxial rotor system is simulated using two trains of airfoils, vertically offset, and traveling in opposite directions. The simulation represents multiple blade crossings in a rotor revolution by specifying horizontal distances between each airfoil in the train based on the circumferential distance between blade tips.
2017-09-17
Technical Paper
2017-01-2492
Dejian Meng, Ziyi Wang, Lijun Zhang, Zhuoping Yu
Abstract In this paper, the initial disc thickness variation (DTV) of a ventilated disc in automotive brake system is modeled as sinusoidal function of the second order. The transient thermomechanical coupling properties of the brake system is simulated using finite element (FE) modeling. The system models and results were verified by a thermomechanical coupling test of a disc brake conducted on a brake dynamometer. By using varied evaluation indexes such as the temperature distribution, the normal stress and the elastic deformation of disc surfaces, the influences of the initial DTV and its direction as well as its amplitude on the thermomechanical coupling characteristics were analyzed.
2017-09-16
Journal Article
2017-01-9183
Tine Christiansen, Johanne Jensen, Andreas Åberg, Jens Abildskov, Jakob Huusom
Abstract A methodology for the development of catalyst models is presented. Also, a methodology of the implementation of such models into a modular simulation tool, which simulates the units in succession, is presented. A case study is presented illustrating how suitable models can be found and used for simulations. Such simulations illustrate the behavior of the individual units and the overall system. It is shown how, by simulating the units in succession, the entire after treatment system can be tested and optimized, because the integration makes it possible to observe the effect of the modules on one another.
2017-09-04
Technical Paper
2017-24-0179
Marco Tonetti, Giorgio Rustici, Massimo Buscema, Luca Ferraris
Abstract Final Euro6d emission legislation with the new homologation cycle and Real Driving Emission requirements has set a strong challenge for the ICE Passenger Car applications. Thanks to their well-known low fuel consumption characteristics, Diesel Engines can play a key role for the fulfillment of the European 2020 CO2 fleet target but need to confirm their capability to fully control noxious emissions even in extreme operating conditions, while restraining the overall engine costs and complexity. CO2 and NOx emissions reduction are considered the main drivers for diesel engine evolution. In this perspective, Exhaust Gas After-treatment and Combustion System have been identified as the two main technology aspects to be developed. The purpose of this paper is to describe the evolution paths of these two technologies and the results achieved so far in terms of noxious emissions reduction.
2017-09-04
Technical Paper
2017-24-0139
Francesco Barba, Alberto Vassallo, Vincenzo Greco
Abstract The aim of the present study is to improve the effectiveness of automotive diesel engine and aftertreatment calibration process through the critical evaluation of several methodologies to estimate the soot mass flow produced by diesel engines fueled by petroleum fuels and filtered by Diesel Particulate Filters (DPF). In particular, its focus has been the development of a reliable simulation method for the accurate prediction of the engine-out soot mass flow starting from Filter Smoke Number (FSN) measurements executed in steady state conditions, in order to predict the DPF loading considering different engine working conditions corresponding to NEDC and WLTP cycles. In order to achieve this goal, the study was split into two main parts: Correlation between ‘wet PM’ (measured by soot filter weighing) and the ‘dry soot’ (measured by the Micro Soot Sensor MSS).
2017-08-24
Magazine
On-Orbit Satellite Refueling Flow Measurement The Path from Concept to Operational Status Radiation Tolerant "Smart Backplanes" for Spacecraft Avionics Using Heat Pipes to Cool Embedded Computers Electronically Dimmable Aircraft Windows How do you block the light of the sun? Eliminating Electrical Arcing in Satellite Systems NASA Miniaturizes Century-Old Radio Sounder Technology Developing an Airborne Optical Systems Testbed (AOSTB) New Class of Excimer-Pumped Atomic Lasers (XPALS) Research demonstrates the viability of an atomic laser having a quantum efficiency greater than one. Hydrodynamic Drag Force Measurement of a Functionalized Surface Exhibiting Superhydrophobic Properties Comparing the skin friction drag effects of a superhydrophobic flat plate to an untreated flat plate of the same material and geometry.
2017-07-27
Magazine
The Rapid Rise of Beryllium-Aluminum Alloys in Aerospace Aeroacoustic Simulation Delivers Breakthroughs in Aircraft Noise Reduction Using System Simulation to Manage Increasing Thermal Loads on Aircraft Fuel Systems Ensuring the Compliance of Avionics Software with DO-178C Microwave Photonic Notch Filter Helps Ensure Critical Mission Success Measuring Propellant Stress Relaxation Modulus Using Dynamic Mechanical Analyzer New testing technique requires less material, gives more accurate results. Combustion Characteristics of Hydrocarbon Droplets Induced by Photoignition of Aluminum Nanoparticles Test methodology allows analysis of combustion dynamics for subscale rocket injectors under super critical conditions. Vapor Pressure Data and Analysis for Selected Organophosphorous Compounds: DIBMP, DCMP, IMMP, IMPA, EMPA, and MPFA Determining the thermophysical properties of chemical warfare agent simulants can help evaluate the performance of defensive equipment.
CURRENT
2017-07-06
Standard
AIR6297
This document describes a method to calculate noise level adjustments at locations behind an airplane (described by an angular offset or directivity) at the start of takeoff roll (SOTR). This method is derived from empirical data from jet aircraft (circa 2004), most of which are configured with wing-mounted engines with high by-pass ratios (Lau, et al., 2012). Methods are also described which apply to modern turboprop aricraft. Calculations of other propagation-related adjustments required for aircraft noise prediction models are described in AIR1845A, ARP5534, ARP866A, and AIR5662.
2017-06-05
Technical Paper
2017-01-1802
Dong chul Lee, Insoo Jung, Jaemin Jin, Stephan Brandl, Mehdi Mehrgou
Abstract In the automotive industry, various simulation-based analysis methods have been suggested and applied to reduce the time and cost required to develop the engine structure to improve the NVH performance of powertrain. This simulation is helpful to set the engine design concept in the initial phase of the powertrain development schedules. However, when using the conventional simulation method with a uniformed force, the simulation results sometimes show different results than the test results. Therefore, in this paper, we propose a method for predicting the radiated noise level of a diesel engine using actual combustion excitation force. Based on the analytical radiated noise development target, we identify the major components of the engine that are beyond this development target by in the frequency range. The components of the problem found in this way are reflected in the engine design of the early development stage to shorten the development time.
2017-06-05
Technical Paper
2017-01-1788
Kishore Chand Ulli, Upender Rao Gade
Abstract Automotive window buffeting is a source of vehicle occupant’s discomfort and annoyance. Original equipment manufacturers (OEM) are using both experimental and numerical methods to address this issue. With major advances in computational power and numerical modelling, it is now possible to model complex aero acoustic problems using numerical tools like CFD. Although the direct turbulence model LES is preferred to simulate aero-acoustic problems, it is computationally expensive for many industrial applications. Hybrid turbulence models can be used to model aero acoustic problems for industrial applications. In this paper, the numerical modelling of side window buffeting in a generic passenger car is presented. The numerical modelling is performed with the hybrid turbulence model Scale Adaptive Simulation (SAS) using a commercial CFD code.
2017-06-05
Technical Paper
2017-01-1892
Yosuke Tanabe, Masanori Watanabe, Takafumi Hara, Katsuhiro Hoshino, Akira Inoue, Masaru Yamasaki
Abstract Predicting the vibration of a motor gearbox assembly driven by a PWM inverter in the early stages of development is demanding because the assembly is one of the dominant noise sources of electric vehicles (EVs). In this paper, we propose a simulation model that can predict the transient vibration excited by gear meshing, reaction force from the mount, and electromagnetic forces including the carrier frequency component of the inverter up to 10 kHz. By utilizing the techniques of structural model reduction and state space modeling, the proposed model can predict the vibration of assembly in the operating condition with a system level EV simulator. A verification test was conducted to compare the simulation results with the running test results of the EV.
2017-06-05
Journal Article
2017-01-1902
Guan Qiao, Geng Liu, Zhenghong Shi, Yawen Wang, Shangjun Ma, Teik Lim
Abstract Actuator and roller screw mechanism are key components of electromechanical brake (EMB) system in automotive and aerospace industry. The inverted planetary roller screw mechanism (IPRSM) is particularly competitive due to its high load-carrying capacity and small assembly size. For such systems, friction characteristic and friction torque generated from rolling/sliding contacts can be an important factor that affects the dynamic performance as well as vibration behavior. This paper investigates the modeling and simulation of the EMB system in early design stage with special attention to friction torque modelling of IPRSM. Firstly, a step-by-step system model development is established, which includes the controller, servo motor, planetary gear train and roller screw mechanism to describe the dynamic behavior of the EMB system.
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