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Technical Paper

Parameter Measurement and Development of a NADSdyna Validation Data Set for a 1994 Ford Taurus

1997-02-24
970564
This paper discusses the development of a 1994 Ford Taurus vehicle model for the National Advanced Driving Simulator's planned vehicle dynamics simulation, NADSdyna. The front and rear suspensions of the Taurus are modeled using recursive rigid body dynamics formulations. To complement vehicle dynamics, subsystems models that include steering, braking, and tire forces are included. These models provide state-of-the-art high fidelity vehicle handling dynamics for real-time simulation. The realism of a particular formulation depend heavily on how the parameters are obtained from the physical system. Therefore, the development of a data set for a particular model is as important as the model itself. The methodology for generating the Taurus data set is presented. The power train model is not yet included, so the simulation is run with the vehicle either at constant speed or decelerating.
Technical Paper

Development of Gasoline Direct Injection Engine

1997-02-24
970541
The major problems of the various mixture formation concepts for direct injection gasoline engines that have been proposed up to the present were caused by the difficulties of preparing the mixture with adequate strength at spark plug in wide range of engine operating conditions. Novel combustion control technologies proposed by Mitsubishi is one of the solution for these problems. By adopting upright straight intake ports to generate air tumble, an electromagnetic swirl injector to realize optimized spray dispersion and atomization and a compact piston cavity to maintain charge stratification, it has become possible to achieve super-lean stratified combustion for higher thermal efficiency under partial loads as well as homogeneous combustion to realize higher performance at full loads. GDI™ (Gasoline Direct Injection) engine adopting these technologies is developed. At partial loads, fuel economy improvement exceeding 30 % is realized.
Technical Paper

Validation Results from Using NADSdyna Vehicle Dynamics Simulation

1997-02-24
970565
This paper presents an evaluation of a vehicle dynamics model intended to be used for the National Advanced Driving Simulator (NADS). Dynamic validation for high performance simulation is not merely a comparison between experimental and simulation plots. It involves strong insight of vehicle's subsystems mechanics, limitations of the mathematical formulations, and experimental predictions. Lateral, longitudinal, and ride dynamics are evaluated using field test data, and analytical diagnostics. The evaluation includes linear and non-linear range of vehicle dynamics response.
Technical Paper

Experimental Testing of a 1994 Ford Taurus for NADSdyna Validation

1997-02-24
970563
As part of the National Advanced Driving Simulator (NADS) program, the Vehicle Research and Test Center (VRTC) in East Liberty, Ohio is evaluating the NADS vehicle dynamics software. As part of VRTC's effort, an extensive vehicle testing program to provide data for the simulation evaluation was performed. This paper describes VRTC's testing of a 1994 Ford Taurus GL passenger car. Each of the test maneuvers run by the Taurus are described, along with instrumentation setup, control actuation, test conditions, and driver procedures. The test data reduction and processing are detailed. Sample results of the testing and an analysis of test repeatability and measurement noise are also presented.
Technical Paper

Development of a Door Test Facility for Implementing the Door Component Test Methodology

1997-02-24
970568
This paper describes the development of an automated Door Test Facility for implementing the Door Component Test Methodology for side impact analysis. The automated targeting and loading of the door inner/trim panels with Side Impact Dummy (SID) ribcage, pelvis, and leg rams will greatly improve its test-to-test repeatability and expedite door/trim/armrest development/evaluation for verification with the dynamic side impact test of FMVSS 214 (Occupant Side Impact Protection). This test facility, which is capable of evaluating up to four (4) doors per day, provides a quick evaluation of door systems. The results generated from this test methodology provide accurate input data necessary for a MADYMO Side Impact Simulation Model. The test procedure and simulation results will be discussed.
Technical Paper

Filter Performance Requirements for Engine Air Induction Systems

1997-02-24
970556
Automotive engine air intake filters are constantly being challenged to deliver higher filtration performances. The need to protect the engine from abrasive contaminants is ever increasing to achieve longer engine life and improved engine performance. This paper discusses some of the key issues affecting engine filter performance. Currently, the SAE J726 procedure is used to test and evaluate engine air induction filters (AIF). The advantages and limitations of this procedure are discussed. Based on this procedure current engine air filtration technologies are also compared. Engine protection requirements are also discussed relating to contaminant size and concentrations. To design robust engine air induction filters, the particle size and concentration ingested by the engine should be controlled. In addition to the overall mass (gravimetric) efficiency of the filters, the fractional size efficiency of these filters should also be measured.
Technical Paper

Air Filter Test Housing Velocity Profile Effects on Filter Efficiencies

1997-02-24
970554
The objective of this work was to estimate the effects of different filter test housings on measurements of automotive air filter efficiency. This objective was motivated by the questions that arise from designing filters on the basis of uniform face velocities and testing filters in housings providing nonuniform velocities. Velocity distributions upstream of a filter were measured with a laser Doppler anemometer and then used with filtration models to estimate filter initial efficiency. A single filter design was tested in a standard and modified SAE J726 Universal Panel Filter Test Housing and in a housing with a shallow angle diffuser followed by a rectangular duct matched to the filter cross section. The velocity measurements showed that the SAE J726 housing presents a very non-uniform flow to the filter. Housing modifications had small effects. The diffuser-duct housing profiles approach fully-developed duct flow profiles.
Technical Paper

The Paper-Tire Concept: A Way to Optimize Tire Force and Moment Properties

1997-02-24
970557
A Paper-Tire is a virtual product defined as a set of force and moment equations that are entirely determined by well defined and widely recognized tire characteristics (such as cornering stiffness, peak location, and slide/peak ratio). The vehicle dynamicist may use the Paper-Tire concept to study the effects of tires with various hypothetical characteristics on vehicle behavior. If the dynamicist discovers a set of characteristics yielding a desired vehicle response, he could then ask tire manufacturers to attempt to develop a tire specification with the preferred characteristics. (There is, of course, no guarantee that tire manufacturers can develop a practical tire with the preferred characteristics.) The paper explains the general principles of the Paper-Tire concept with the help of the BNPS model (derived from the ‘Magic Formula’). A limited set of examples for tire cornering and braking performance are provided at a single load; further possible developments are indicated.
Technical Paper

Wicking Fiber Chemisorption for Air Quality Improvement

1997-02-24
970555
The removal of toxic, corrosive, irritant, and odorous gases is a key strategy in improving air quality in any closed space. The technologies of granulated activated carbon or chemically impregnated dry media are commonly employed to address this issue. Both of these methods have their limitations in manufacturability, volume of space, and/or pressure drop associated with use in a given application. A new air quality technology has been developed which integrates liquid based chemisorption gas treatment with a shaped fiber media carrier. The patented wicking fiber shape holds more than its own weight in active reagents within intra-fiber channels. While the liquid volume is captured and retained through capillary action, a large surface area of the chemisorptive liquid is presented to the air flow for reaction and neutralization of the target contaminant gases. The wicking fibers may be implemented as fiber bundles, woven materials, or as non-wovens.
Technical Paper

Matching Vehicle Responses Using the Model-Following Control Method

1997-02-24
970561
The Variable Dynamic Testbed Vehicle (VDTV) is presently being developed by the National Highway Traffic Safety Administration (NHTSA). It is being designed to have a “steer-by-wire” front steering system and an independent rear steering system. These steering systems enable the VDTV to emulate the directional control characteristics of a broad range of passenger vehicles. In this study, a “model-following” control method is used to modify both the steady-state and transient lateral response characteristics of a small-size VDTV to match those of compact-size and mid-size vehicles. For two classes of steering inputs considered in this study (“pseudo-step” and “sinusoidal”), the model-following control design method allowed the VDTV to accurately and robustly track the lateral responses of the target vehicles over a range of forward speed.
Technical Paper

Variable Dynamic Testbed Vehicle: Dynamics Analysis

1997-02-24
970560
The Variable Dynamic Testbed Vehicle (VDTV) concept has been proposed as a tool to evaluate collision avoidance systems and to perform driving-related human factors research. The goal of this study is to analytically investigate to what extent a VDTV with adjustable front and rear anti-roll bar stiffnesses, programmable damping rates, and four-wheel-steering can emulate the lateral dynamics of a broad range of passenger vehicles. Using a selected compact-sized automobile as a baseline, our study indicated this baseline vehicle can be controlled to emulate the lateral response characteristics (including the vehicle's understeer coefficient and the 90% lateral acceleration rise time in a J-turn maneuver) of a fleet of production vehicles, from low to high lateral acceleration conditions.
Technical Paper

A Vehicle Dynamics Tire Model for Both Pavement and Off-Road Conditions

1997-02-24
970559
This paper describes a tire model designed for the full range of operating conditions under both on- and off-road surface conditions. The operating conditions include longitudinal and lateral slip, camber angle and normal load. The model produces tire forces throughout the adhesion range up through peak coefficient of friction, and throughout the saturation region to limit slide coefficient of friction. Beyond the peak coefficient of friction region, the off-road portion of the model simulates plowing of deformable surfaces at large side slip angles which can result in side forces significantly above the normal load (e.g., equivalent coefficients of friction greatly exceeding unity). The model allows changing the saturation function depending the surface currently encountered by a given tire in the vehicle dynamics model.
Technical Paper

Modeling of the Engine Mechanical System Crankshaft, Its Bearings and Supports

1997-02-24
970511
The main features of suggested model are as follows. Elastic crankshaft rotates in main bearings, bearing supports elastically deform in the linear and the angular directions under action of forces resulted from journals and bearings interaction. The linear and the angular elasticity limits of supports and crankshaft of a particular engine is a subject of FEM study. The model of dynamically loaded bearings considers the misalignment and the angular displacements of journals and mixed lubrication conditions. A new method to obtain hydrodynamic forces as well as moments is described. In addition to the existing bearing performance evaluation criteria, the deviation criteria has been suggested. The model and its modifications have been on-going basis for study and the improvement of several types of diesel locomotive engines. Some of the results of these studies are presented.
Technical Paper

Real-Time Simulation of an Engine Model and a Vehicle Model Using Asynchronous Simulation Techniques

1997-02-24
970510
Automotive systems often employ a variety of intercoupled embedded controllers. To ensure that the controller actions are coordinated and that unwanted interaction does not occur, system testing is necessary over the entire operating range of the automotive systems. A cost effective, safe, and convenient means to perform much of the testing of embedded controller code is to use real-time simulation for all or major parts of the automotive system. However, the integration of various automotive system models and controllers into a single simulation model for hard real-time is a difficult task which is complicated by the usual approach of synchronizing the various computational tasks and I/O activites. This paper describes a new methodology involving asynchronous operation of processors and processes.
Technical Paper

Air-Fuel Flow Modeling Applied to the Reduction of Air-Fuel Ratio Excursions During Transients on Port Injected S.I. Engines

1997-02-24
970513
Transient operation in port-injected engines often results in long lasting air-fuel ratio excursions. These excursions lead to high levels of pollutant emissions even in three-way catalyst equipped vehicles. The reduction of these excursions can be achieved by controlling fuel injection, but the exact amount of fuel to be injected is dependant on air flow and deposited fuel dynamics. This paper describes a complete model of the intake port, taking into account physical evolutions of three phases in a bidimensional geometry. Back-flow of hot burned gases, droplet trajectories, droplet evaporation, deposited fuel film flow, deposited fuel film evaporation, and air flow are taken into account. The model is used to predict air-fuel ratio excursions during engine transients. Results are compared to measurements made on a real four-cylinder engine with an oxygen sensor on the exhaust port of one cylinder, for several operating conditions.
Technical Paper

Nonlinear Modeling and Control of I.C. Engine Idle Speed

1997-02-24
970512
Presented in this paper is the nonlinear modeling and control of the idle speed of a Ford 4.6L-2 valve V-8 fuel injected engine. The nonlinear model of the engine is based on a Hammerstein type model which is identified through input-output data without a priori knowledge of the engine dynamics. The nonlinear model is used in a frequency domain controller design methodology to achieve the performance goal of maintaining the engine idle speed within a prespecified asymmetric output tolerance despite external torque disturbances. An experimental verification of the nonlinear controller is included.
Technical Paper

Development of High Toughness Microalloyed Steel Bars and Its Application to Steering Racks

1997-02-24
970515
Based on fundamental study about the toughness of hot rolled microalloyed steels, a new steel composed of 0.4 % carbon, 1.10 % manganese, 0.5 % chromium and 0.15 % vanadium was developed. The steel shows high toughness and high proof stress after well-controlled hot rolling. The newly designed steering racks for passenger cars using the steel bar have properties equivalent to the racks of conventional quenched and tempered carbon steels.
Technical Paper

Optimizing Forgings for Automotive Transmission Hubs by Warm Forming Vanadium-Microalloyed Steels

1997-02-24
970517
An experimental study of two warm and hot forged 0.30% carbon ferrite/pearlite microalloyed steels demonstrates that the optimal combination of strength and toughness is achieved in a warm forged, fan cooled condition. The properties of the warm forged microalloyed steel approached the combination of strength and toughness achieved in a heat treated 1037 steel, tested at an equivalent hardness level of 20 to 28 HRC. These warm forged microalloyed steels were successfully substituted for heat treated 1037/1040 steels in two automotive transmission hub applications. The benefits of implementing the warm forged microalloyed steel hubs include the elimination of the heat treatment, and the associated costs and problems.
Technical Paper

An Algorithm for Calculating the Air/Fuel Ratio from Exhaust Emissions

1997-02-24
970514
A confusing number of equations have been developed and published for calculating the air/fuel ratio of an operating engine from the composition of its exhaust gasses. These methods make varying use of the information available from the gas concentration measurements, but they all are based on the same chemistry of combustion. The method described here is a single algorithm that duplicates the results of all the well known published equations and can adapt to different measurement circumstances, such as when an oxygen measurement is not available or if the gas sampling point is moved to after the catalyst. Data are presented to demonstrate the equivalence of the algorithm and equation evaluations.
Technical Paper

Trend of Bolts for Use in Automobiles and Development of Class 10.9 Low Carbon Boron Steel Bolt

1997-02-24
970516
There are strong demands for reduced production costs of ordinary bolts, of which a large number are used throughout automobiles. In addition, there are continued demands for higher performance and lower weight in automobiles. For this reason, there is an increasing trend to develop steel for high strength bolts or to adopt the plastic region tightening method. At present, the principal materials used in high strength bolts of class 10.9 are medium carbon alloy steel. When a low carbon boron steel bolt is used as a class 10.9 bolt under high stress, delayed fracture may occur, so that these cannot always be used for the body and chassis applications. The authors have developed a new low carbon boron steel with increased delayed fracture strength on the same order as that of JIS-SCM435 (equivalent to SAE4135) medium carbon alloy steel. Attention was focused principally on decreasing the amounts of phosphorus and sulfur in the steel.
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