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0-D and 1-D Modeling and Numerics, 2018

2018-04-03
Papers in the session cover zero-dimensional, one-dimensional, and quasi-dimensional models for simulation of SI and CI engines with respect to: engine breathing, boosting, and acoustics; SI combustion and emissions; CI combustion and emissions; fundamentals of engine thermodynamics; numerical modeling of gas dynamics; thermal management; mechanical and lubrication systems; system level models for controls; and system level models for vehicle fuel economy and emissions predictions.
Collection

0-D and 1-D Modeling and Numerics, 2017

2017-03-28
Papers in the session cover zero-dimensional, one-dimensional, and quasi-dimensional models for simulation of SI and CI engines with respect to: engine breathing, boosting, and acoustics; SI combustion and emissions; CI combustion and emissions; fundamentals of engine thermodynamics; numerical modeling of gas dynamics; thermal management; mechanical and lubrication systems; system level models for controls; and system level models for vehicle fuel economy and emissions predictions.
Video

Advances of Virtual Testing and Hybrid Simulation in Automotive Performance and Durability Evaluation

2012-02-15
Virtual testing is a method that simulates lab testing using multi-body dynamic analysis software. The main advantages of this approach include that the design can be evaluated before a prototype is available and virtual testing results can be easily validated by subsequent physical testing. The disadvantage is that accurate specimen models are sometimes hard to obtain since nonlinear components such as tires, bushings, dampers, and engine mounts are hard to model. Therefore, virtual testing accuracy varies significantly. The typical virtual rigs include tire and spindle coupled test rigs for full vehicle tests and multi axis shaker tables for component tests. Hybrid simulation combines physical and virtual components, inputs and constraints to create a composite simulation system. Hybrid simulation enables the hard to model components to be tested in the lab.
Video

Real-World Driving Pattern Recognition for Adaptive HEV Supervisory Control: Based on Representative Driving Cycles in Midwestern US

2012-06-18
Impact of driving patterns on fuel economy is significant in hybrid electric vehicles (HEVs). Driving patterns affect propulsion and braking power requirement of vehicles, and they play an essential role in HEV design and control optimization. Driving pattern conscious adaptive strategy can lead to further fuel economy improvement under real-world driving. This paper proposes a real-time driving pattern recognition algorithm for supervisory control under real-world conditions. The proposed algorithm uses reference real-world driving patterns parameterized from a set of representative driving cycles. The reference cycle set consists of five synthetic representative cycles following the real-world driving distance distribution in the US Midwestern region. Then, statistical approaches are used to develop pattern recognition algorithm. Driving patterns are characterized with four parameters evaluated from the driving cycle velocity profiles.
Video

Evolution of the Space Shuttle Primary Avionics Software and Avionics for Shuttle Derived Launch Vehicles

2012-03-21
As a result of recommendation from the Augustine Panel, the direction for Human Space Flight has been altered from the original plan referred to as Constellation. NASA's Human Exploration Framework Team (HEFT) proposes the use of a Shuttle Derived Heavy Lift Launch Vehicle (SDLV) and an Orion derived spacecraft (salvaged from Constellation) to support a new flexible direction for space exploration. The SDLV must be developed within an environment of a constrained budget and a preferred fast development schedule. Thus, it has been proposed to utilize existing assets from the Shuttle Program to speed development at a lower cost. These existing assets should not only include structures such as external tanks or solid rockets, but also the Flight Software which has traditionally been a ?long pole? in new development efforts. The avionics and software for the Space Shuttle was primarily developed in the 70's and considered state of the art for that time.
Video

Applying Critical-System Java to the Challenges of SMP Platforms

2012-03-21
In recent years, all major microprocessor manufacturers are transitioning towards the deploymenet of multiple processing cores on every chip. These multi-core architectures represent the industry consensus regarding the most effective utilization of available silicon resources to satisfy growing demands for processing and memory capacities. Porting off-the-shelf software capabilities to multi-core architectures often requires significant changes to data structures and algorithms. When developing new software capabilities specifically for deployment on SMP architectures, software engineers are required to address specific multi-core programming issues, and in the ideal, must do so in ways that are generic to many different multi-core target platforms. This talk provides an overview of the special considerations that must be addressed by software engineers targeting multi-core platforms and describes how the Java language facilitates solutions to these special challenges.
Technical Paper

Innovative Material Characterisation Methodology for Tyre Static and Dynamic Analyses

2020-09-30
2020-01-1519
Tyre structures are based on composite materials that constitute numerous layers, each providing specific properties to the tyre mechanic and dynamic behaviour. In principle, the understanding of the partial contributions of the individual layers requires knowledge of its mechanical properties. In case of non-availability of such critical information, it is difficult to perform tyre FE analyses. In the current work, a methodology is proposed to study the tyre static and dynamic behaviour to estimate its constituents properties based on the measured quasi-static responses of the tyre for certain specific loads. As a first step, a simplified tyre numerical model with standard rubber material properties is modeled that can substantively predict the necessary tyre static responses, i.e. radial, longitudinal and lateral stiffness. These responses are correlated with the physical tyre response that are measured using a kinematic and compliance (K&C) test rig in the laboratory.
Technical Paper

Numerical Analysis of the Influences of Wear on the Vibrations of Power Units

2020-09-30
2020-01-1506
Numerical Analysis of the Influences of Wear on the Vibrations of Power Units Yashwant Kolluru, Rolando Doelling eBike Department Robert Bosch GmbH Kusterdingen, Germany yashwant.kolluru@de.bosch.com rolando.doelling@de.bosch.com Lars Hedrich Institute of Informatics Goethe University Frankfurt Frankfurt, Germany hedrich@em.informatik.uni-frankfurt.de The prime factor, which influences vibrations of electro-mechanical drives, is wear at the components. This paper discusses the numerical methods developed for abrasion, vibration calculations and the coupling between wear and NVH models of drive unit. Wear is a complex process and understanding it is essential for vibro-acoustics. The paper initially depicts finite element static model used for wear calculations. The special subroutines developed, aids in coupling the wear equations, various contact and friction formulations to the numerical model.
Technical Paper

Impact of Manufacturing Inaccuracies on the Acoustic Performance of Sound Insulation Packages With Plate-like Acoustic Metamaterials

2020-09-30
2020-01-1562
Thin plate-like metamaterials (e.g. membrane-type acoustic metamaterials or inhomogeneous plates) have a high potential for improving the sound transmission loss of sound insulation packages, especially in the challenging low-frequency regime. These types of metamaterials have been previously shown to achieve very high sound transmission loss values which can exceed the corresponding mass-law values considerably. However, like many other metamaterial realizations, their extraordinary acoustical performance relies on the periodicity of the sub-wavelength sized unit cells. In particular, for plate-like acoustic metamaterials (PAM) most theoretical and numerical investigations assume a perfect placement of equal added masses - an idealization which cannot be achieved in industrial manufacturing of these metamaterials. This contribution investigates the impact of randomized inaccuracies that can occur in manufacturing on the sound reduction behavior of PAM.
Technical Paper

Development of the Active Sound Generation Technology using Motor Driven Power Steering System

2020-09-30
2020-01-1536
As original engine sound is usually not enough to satisfy the driver’s desire for the sporty and fascinating sound, active noise control (ANC) and active sound design (ASD) have been great technologies in automobiles for a long time. However, these technologies which enhance the sound of vehicle using loud speakers or electromagnetic actuators etc. lead to the increase of cost and weight due to the use of external amplifier or external actuators. This paper presents a new technology of generating a target sound by the active control of a permanent magnet synchronous motor (PMSM) which is already mounted in vehicle. Firstly, an algorithm of this technology, called an active sound generation (ASG), is introduced with those signal conversion process, and then the high frequency noise issue and its countermeasure are presented.
Video

Optimal Scheduling and Delay Analysis for AFDX End-Systems

2012-03-21
The present work aims at the reduction of transmission delay at the level of AFDX ES (Avionics Full Duplex Switched Ethernet End-Systems). To this end, two approaches, namely Network Calculus and response time analysis (RTA), are employed in the computation of upper bound delay. To evaluate the delay regarding different scheduling policies, the arrival curve of the flow on output of ES is established for given traffic shaping algorithm and service mode. Computational analysis shows that Bandwidth Allocation Gap (BAG) based scheduling is the optimal policy at the level of AFDX ES, which leads to the tightest output arrival curve among all possible scheduling policies. BAG-based scheduling consists in assigning higher priority to virtual links with smaller BAG thus corresponding to the well known Rate-Monotonic Algorithm. Furthermore, schedulability criterion are established based on RTA.
Technical Paper

Development and Evaluation of the Simulation of the Compression-Ignition Engine

1965-02-01
650451
The first part of the paper deals with the mathematical model and computer program for simulating a compression-ignition engine. The various assumptions used and the effects of these assumptions on the results are discussed. The second part of the paper evaluates results of the engine simulation program by comparisons with experimental data and with other simplified cycle calculations. The comparisons with experimental data include motoring, part load, and full load data for a speed range of 1400–3200 rpm. The simulation results show good agreement with experimental pressure-volume diagrams. The computed trends of volumetric efficiency, heat rejection, and metal part temperatures show reasonable agreement with experimental data.
Technical Paper

On the Mathematical Model of Motored Compression Temperature

1965-02-01
650453
This paper sets up a mathematical model for measuring end-gas temperatures in spark ignition engines and the compression temperatures in compression ignition engines. The model is based on a modified thermodynamic equation, for which the nonlinear least square method is used to fit the parameters.
Technical Paper

An Analytical Method for Optimizing the Scavenging Process of Uniflow Two-Cycle Diesel Engines

1965-02-01
650447
A mathematical model of the scavenging process of uniflow two-cycle diesel engines is proposed. It assumes that certain general characteristics of a particular engine type are known. With a number of simplifying assumptions, the scavenging process and engine performance can then be analyzed by means of a digital computer. Experimental results are used to demonstrate the validity of the analysis. A number of scavenging system variables are investigated and a combination is proposed which should give optimum performance.
Technical Paper

The Relationship of a Gasket’s Physical Properties to the Sealing Phenomenon

1965-02-01
650431
The internal combustion engine cylinder head gasket is the most complex of all gasket applications. This is due to the variety of seals and sealing conditions which must be achieved in a single gasket. Some of the physical characteristics studied for such gaskets include spring rate, stress relaxation, torque loss, and permeability of current materials and elements used in these constructions. The effects of temperature, sealing stress, thickness, geometry, and engine operation on the properties of gaskets are discussed. In one of the theoretical derivations given, a mathematical model of a viscoelastic material is used to explain the results of certain experimental testing. Major emphasis is placed on spring rate and stress relaxation, which are directly related to fluctuations of sealing pressure and loss of torque which must be controlled in order to achieve satisfactory sealing.
Technical Paper

Dynamic Brake Balance via the Computer

1966-02-01
660399
The evaluation of commercial vehicle brake system balance is a complex analytical task. Tractor-trailer combinations frequently include different brake designs on different axles, which have widely varying characteristics. In addition, variations in brake parameters such as pressure, response times, linings, and heat transfer under various operating conditions add to the complexity of analyzing the brake system. This paper describes a mathematical model of the vehicle brake system and a program for a digital computer to solve the mathematical expressions. Using the computer to simulate dynamic brake system operation, current designs can be evaluated rapidly for effectiveness and possible improvement, and future designs can be analyzed prior to expensive prototype fabrication.
Technical Paper

A Method for Synthesis and Selection of Propulsion Plants for Submarines

1964-01-01
640475
New concepts for submarine propulsion plants are continuously being presented to the Navy for review and possible application. An analytical method is now being used to determine the effect of powerplant weight and thermal efficiency on the cruising radius, speed, and vessel displacement. A mathematical model representing the propulsion plant and vessel hull was prepared and, by means of a digital computer, the effects of varying several design parameters were studied. By comparing the predicted performance of several types of powerplants with the results of the computer study, it is possible to select those which justify further development for Navy use.
Technical Paper

The Influence of Compression Ratio and Dissociation on Ideal Otto Cycle Engine Thermal Efficiency

1962-01-01
620557
THIS PAPER PRESENTS a theoretical analysis of the ideal adiabatic Otto cycle engine. The analysis was made to examine the influence of compression ratio and dissociation on engine thermal efficiency over an extreme range of compression ratios (that is, 4–300) to see if chemical dissociation could limit Otto cycle engine thermal efficiency. Assuming isooctane, benzene, ethyl alcohol, and nitromethane to be the fuels being consumed, the effects of compression ratio and mixture strength on the thermodynamic properties and equilibrium species concentration of the working fluid at every step in the ideal Otto cycle were computed. The calculations were made using a mathematical model of the ideal adiabatic engine which had been programmed to an IBM 704 digital computer. With the model, the effect of compression ratio on engine thermal efficiency was calculated over a wide range of operating conditions.
Technical Paper

An Analysis of the Ideal Otto Cycle, Including the Effects of Heat Transfer, Finite Combustion Rates, Chemical Dissociation, and Mechanical Losses

1963-01-01
630082
This detailed analysis of the Otto cycle considers the effects of dissociation, finite reaction kinetics, and irreversibilities such as heat transfer and mechanical friction on cycle performance and efficiency, and provides a highly flexible tool for investigating the complex relationships among engine variables. This mathematical model and the accompanying computer program offer a substantial computational advantage over the previous methods that employ charts and graphs and require a large amount of manual calculations. Also, the ability of this scheme to consider the effects of heat transfer and other irreversibilities considerably increases the value of the results.
Technical Paper

Vehicle Stability Studied with a Non-Linear Seven Degree Model

1967-02-01
670476
This paper describes a new mathematical model developed to account for nonlinearities between vehicles and tires. Lateral and vertical stiffnesses of tires are investigated because they have basic influences on the behavior of the car in sudden and severe maneuvers. The new procedure allows operational simulation and simplifies analyses of cars with different types of tires and suspensions. This is demonstrated by comparing vehicles fitted with a basic tire, a tire with larger lateral stiffness, and a tire with larger cornering stiffness. Calculations show the damping effect of lateral stiffness and the need for increasing both cornering and lateral stiffnesses.
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