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Technical Paper

14 Degree-of-Freedom Vehicle Model for Roll Dynamics Study

2006-04-03
2006-01-1277
A vehicle model is an important factor in the development of vehicle control systems. Various vehicle models having different complexities, assumptions, and limitations have been developed and applied to many different vehicle control systems. A 14 DOF vehicle model that includes a roll center as well as non-linear effects due to vehicle roll and pitch angles and unsprung mass inertias, is developed. From this model, the limitations and validity of lower order models which employ different assumptions for simplification of dynamic equations are investigated by analyzing their effect on vehicle roll response through simulation. The possible limitation of the 14 DOF model compared to an actual vehicle is also discussed.
Technical Paper

A Case Study in Remote Connectivity to Automotive Communication Networks

2001-03-05
2001-01-0069
This paper describes a case study led by Science Applications International Corporation (SAIC) of Dayton, OH USA and Dearborn Group Inc. to prove the feasibility of employing Telematics technologies to the vehicle test and measurement industry. Many test functions can be automated through the use of secure wireless technologies. For example, vehicle data can be dynamically monitored on the vehicle and data meeting pre-determined criteria could be downloaded via the wireless communications center. Additionally, central, real-time wireless monitoring of vehicle fleets provides the vehicle fleet manager with the ability to manage multiple tests simultaneously, thus improving efficiencies and potentially reducing manpower costs and compressing test schedules.
Technical Paper

A Comparison of Burn Characteristics and Exhaust Emissions from Off-Highway Engines Fueled by E0 and E85

2004-01-16
2004-28-0045
Ethanol fuel has received renewed attention in recent years because of its oxygenate content and its potential to reduce greenhouse gas emissions from spark ignition engines. The economic impact on farm industry has been one of the drivers for its use in engines in the U.S. Although ethanol, in various blends, has been used in automotive engines for almost a decade the fuel has seldom been utilized in off-highway engines where the fuel systems are not well controlled. This investigation was conducted to evaluate exhaust emissions and combustion characteristics of E85 fuel in an off-highway engine used in farm equipment. A single-cylinder, four-stroke, spark ignition engine equipped with a carburetor was used to investigate combustion and exhaust emissions produced by gasoline and blends of gasoline and ethanol fuels. The engine fuel system was modified to handle flow rates required by the engine. A variable size-metering orifice was used to control air-to-fuel ratios.
Technical Paper

A Fitting Algorithm for Determination of Minimum Zone Form Tolerances

1996-05-01
961642
In this paper, a new algorithm, named Nonlinear Optimization Method (NOM) has been mathematically and computationally developed for several geometric elements. The initial condition of the NOM is obtained by LSM, then the minimum zone is optimized in accordance with tolerancing principles in ANSI Y14.5.1M. The results are verified to be the Minimum Zone Evaluation (MZE) for the inspected geometric features. The algorithm, together with its computational realization programs, are proved to be considerably reliable and robust for practical applications.
Technical Paper

A Modular Designed Three-phase ~98%-Efficiency 5kW/L On-board Fast Charger for Electric Vehicles Using Paralleled E-mode GaN HEMTs

2017-03-28
2017-01-1697
Most of the present electric vehicle (EV) on-board chargers utilize a conventional design, i.e., a boost-type Power Factor Correction (PFC) controller followed by an isolated DC/DC converter. Such design usually yields a ~94% wall-to-battery efficiency and 2~3kW/L power density at most, which makes a high-power charger, e.g., 20kW module difficult to fit in the vehicle. As described in this paper, first, an E-mode GaN HEMT based 7.2kW single-phase charger was built. Connecting three such modules to the three-phase grid allows a three-phase >20kW charger to be built, which compared to the conventional three-phase charger, saves the bulky DC-bus capacitor by using the indirect matrix converter topology. To push the efficiency and power density to the limit, comprehensive optimization is processed to optimize the single-phase module through incorporating the GaN HEMT switching performance and securing its zero-voltage switching.
Technical Paper

A Real-Time Computer System for the Control of Refrigerant Flow

1997-02-24
970108
This paper presents a real-time computer system for the control of refrigerant flow in an automotive air conditioning system. This is an experimental system used to investigate the potential advantages of electronic flow control over conventional flow control (using an orifice tube or thermal expansion valve). Two features of this system are presented. First, the system organization is described. Second, the control and interface software are presented. The emphasis is on the software. The system is organized as a closed loop control system. The inputs to the controller are measurements of the refrigerant system. In particular, thermocouples are used to measure the refrigerant temperature before and after the evaporator. The analog thermocouple signals are converted to digital form by an off-the-shelf, portable, data acquisition system (DAQ). Via a parallel port link, these digital measurements are transfered to a laptop computer.
Technical Paper

A Rear Spoiler of a New Type that Reduces the Aerodynamic Forces on a Mini-Van

2006-04-03
2006-01-1631
The Low Mass Vehicle (LMV) that is a minivan designed to compete with the Toyota Echo but with 30% less mass has been used for the research in the Institute for Advanced Vehicle Systems. To reduce the aerodynamic forces on the LMV, the present authors have developed a rear spoiler of a new type based on the principles of fluid dynamics and through numerical computations. This new spoiler has been developed in such a way that the aerodynamic drag as well as lift on vehicles having a bluff back can be reduced when the new spoiler is attached to them. Numerical simulations show that the aerodynamic drag and lift on the LMV moving at 30 m/s reduce by 5 % and more than 100 %, respectively, when the new spoiler is attached to it.
Technical Paper

A Structural Stress Recovery Procedure for Fatigue Life Assessment of Welded Structures

2017-03-28
2017-01-0343
Over the decades, several attempts have been made to develop new fatigue analysis methods for welded joints since most of the incidents in automotive structures are joints related. Therefore, a reliable and effective fatigue damage parameter is needed to properly predict the failure location and fatigue life of these welded structures to reduce the hardware testing, time, and the associated cost. The nodal force-based structural stress approach is becoming widely used in fatigue life assessment of welded structures. In this paper, a new nodal force-based structural stress recovery procedure is proposed that uses the least squares method to linearly smooth the stresses in elements along the weld line. Weight function is introduced to give flexibility in choosing different weighting schemes between elements. Two typical weighting schemes are discussed and compared.
Technical Paper

A Study on Tire Non-Steady State Cornering Characteristics Using Experimental Modal Parameters

2000-03-06
2000-01-0362
Based on the modeling of tire vertical characteristics and steady state cornering properties, the model of tire nonsteady cornering is established in this paper using the tire modal parameters extracted experimentally. The dynamic deformation of tire footprint and the influence of tire width for self-aligning torque are taken into account. The footprint is segmented and the influence of speed on non-steady characteristics is included. The analytical formulae for calculation of transfer-function of lateral force and self-aligning torque with respect to lateral displacement and yaw angle are derived. The non-steady characteristics of tire under different loads can be calculated. The calculated results are consistent with the experimental results in the literature. This shows that the tire nonsteady model can be established conveniently using experimental modal parameters. The dynamic characteristics of tires under different working conditions can be calculated directly.
Technical Paper

A Transportable Instrumentation Package for In-Vehicle On-Road Data Collection for Driver Research

2013-04-08
2013-01-0202
We present research in progress to develop and implement a transportable instrumentation package (TIP) to collect driver data in a vehicle. The overall objective of the project is to investigate the symbiotic relationship between humans and their vehicles. We first describe the state-of-art technologies to build the components of TIP that meet the criteria of ease of installation, minimal interference with driving, and sufficient signals to monitor driver state and condition. This method is a viable alternative to current practice which is to first develop a fully instrumented test vehicle, often at great expense, and use it to collect data from each participant as he/she drives a prescribed route. Another practice, as for example currently being used in the SHRP-2 naturalistic driving study, is to install the appropriate instrumentation for data collection in each individual's vehicle, often requiring several hours.
Technical Paper

A Value Analysis Tool for Automotive Interior Door Trim Panel Materials and Process Selection

2007-04-16
2007-01-0453
This paper describes a computerized value analysis tool (VAT) developed to aid automotive interior designers, engineers and planners to achieve the high levels of perceived quality of materials used in automotive door trim panels. The model requires a number of inputs related to types of materials, their manufacturing processes and customer perceived quality ratings, costs and importance of materials, features located in different areas of the door trim panel, etc. It allows the user to conduct iterative evaluation of total cost, total weighted customer perceived quality ratings, and estimates of perceived value (perceived quality divided by cost) for different door trim areas as well as the entire door trim panel. The VAT, thus, allows value and cost management related to materials and processing choices for automotive interiors.
Journal Article

Active Thermal Management with a Dual Mode Coolant Pump

2013-04-08
2013-01-0849
A GT-suite commercial code was used to develop a fully integrated model of a light duty commercial vehicle with a V6 diesel engine, to study the use of a BorgWarner dual mode coolant pump (DMCP) in active thermal management of the vehicle. An Urban Dynamometer Driving Schedule (UDDS) was used to validate the simulation results with the experimental data. The conventional mechanical pump from the validated model was then replaced with the dual mode coolant pump. The control algorithm for the pump was based on controlling the coolant temperature with pump speed. Maximum electrical speed of the pump and the efficiency of the pump were used to determine whether the pump should run in mechanical or electrical mode. The model with the dual mode coolant pump was simulated for the UDDS cycle to demonstrate the effectiveness of control strategy.
Technical Paper

An Elastoplastic Damage Coupled Analysis for Crashworthiness of Aluminum Materials

1996-02-01
960169
This paper presents a comprehensive damage model capable of predicting crash behavior of aluminum structures under varying applied loading conditions. The damage model has been implemented in a general purpose explicit nonlinear finite element code and crash analysis has been carried out for aluminum tubes. The response obtained from the finite element analysis shows a close agreement with the experimental data. The finite element program containing the proposed generalized damage model can be used to analyze aluminum structures subjected to complex service loading conditions and identify associated failure modes to assess crashworthiness.
Technical Paper

An Examination of Driver Eye Glance Behavior, Navigational Errors, and Subjective Assessments While Using In-Vehicle Navigational Systems With and Without Landmark Enhancements

2017-03-28
2017-01-1375
This study investigated the effects of three navigation system human-machine interfaces (HMIs) on driver eye-glance behavior, navigational errors, and subjective assessments. Thirty-six drivers drove an unfamiliar 3-segment route in downtown Detroit. HMIs were 2D or 3D (level-of-detail) electronic map display + standard voice prompts, or 3D map-display augmented by photorealistic images + landmark-enhanced voice prompts. Participants drove the same three route segments in order but were assigned a different HMI condition/segment in a 3-period/3-treatment crossover experimental design. Results indicate that drivers’ visual attention using the advanced navigation systems HMIs were within US Department of Transportation recommended visual distraction limits. More turns missed in the first route segment, regardless of HMI, were attributable to greater route complexity and a late-onset voice prompt. Participant’s ratings of HMIs were influenced by the context in which that HMI was used.
Technical Paper

Analysis and Optimization of Seat and Suspension Parameters for Occupant Ride Comfort in a Passenger Vehicle

2018-04-03
2018-01-1404
This study presents a methodology for comparative analysis of seat and suspension parameters on a system level to achieve minimum occupant head displacement and acceleration, thereby improving occupant ride comfort. A lumped-parameter full-vehicle ride model with seat structures, seat cushions and five occupants has been used. Two different vehicle masses are considered. A low amplitude pulse signal is provided as the road disturbance input. The peak vertical displacement and acceleration of the occupant’s head due to the road disturbance are determined and used as measures of ride comfort. Using a design of experiments approach, the most critical seat cushion, seat structure and suspension parameters and their interactions affecting the occupant head displacement and acceleration are determined. An optimum combination of parameters to achieve minimum peak vertical displacement and acceleration of the occupant’s head is identified using a response surface methodology.
Technical Paper

Analysis of Cumulative Damage in a Bumper Due to Multiple Low Speed Impacts

2000-03-06
2000-01-0631
The paper presents a method of analysis based on the theory of damage mechanics to quantify the degree of damage in an engineering structure under load. The method is incorporated into a Ford in-house finite element program called FCRASH that is applied to analyze the cumulative damage in a bumper under multiple low speed impacts. The numerical results calculated at the peak value of the contact force are compared with the test results. The FEA results are used to identify the locations of the hotspot in the bumper system and the predicted location where a potential crack would initiate. The microscopic observations showed damage in the area predicted with the finite element program after the specified number of impacts.
Journal Article

Analysis of Trimming Processes for Advanced High Strength Steels

2008-04-14
2008-01-1446
Current die design recommendations attempt to limit the production of burrs through accurate alignment of the upper and lower edges. For common automotive exterior sheet, this translates to a gap less than 0.06mm. Unfortunately, the tolerances required by such standards often exceed the capabilities of many trim dies. The objective of the research described in this paper is to study the mechanisms of burrs generation and their impact on AHSS formability in stretch flanging. Experimental results on influence of trimming conditions on the shape of the sheared surface will be combined with the results of stretching strips after trimming.
Technical Paper

Application of Fatigue Life Prediction Methods for GMAW Joints in Vehicle Structures and Frames

2011-04-12
2011-01-0192
In the North American automotive industry, various advanced high strength steels (AHSS) are used to lighten vehicle structures, improve safety performance and fuel economy, and reduce harmful emissions. Relatively thick gages of AHSS are commonly joined to conventional high strength steels and/or mild steels using Gas Metal Arc Welding (GMAW) in the current generation body-in-white structures. Additionally, fatigue failures are most likely to occur at joints subjected to a variety of different loadings. It is therefore critical that automotive engineers need to understand the fatigue characteristics of welded joints. The Sheet Steel Fatigue Committee of the Auto/Steel Partnership (A/S-P) completed a comprehensive fatigue study on GMAW joints of both AHSS and conventional sheet steels including: DP590 GA, SAE 1008, HSLA HR 420, DP 600 HR, Boron, DQSK, TRIP 780 GI, and DP780 GI steels.
Technical Paper

Aqueous Corrosion of Experimental Creep-Resistant Magnesium Alloys

2006-04-03
2006-01-0257
This paper presents a comparison of aqueous corrosion rates in 5% NaCl solution for eight experimental creep-resistant magnesium alloys considered for automotive powertrain applications, as well as three reference alloys (pure magnesium, AM50B and AZ91D). The corrosion rates were measured using the techniques of titration, weight loss, hydrogen evolution, and DC polarization. The corrosion rates measured by these techniques are compared with each other as well as with those obtained with salt-spray testing using ASTM B117. The advantages and disadvantages of the various corrosion measurement techniques are discussed.
Technical Paper

CFD Investigation of the Scavenging Process in a Two-Stroke Engine

1994-10-01
941929
Computational fluid dynamics simulations of the gas exchange process in a crankcase-scavenged, two-stroke engine were used to study the scavenging characteristics of the engine over the whole operating range and to investigate the effects of various design changes. The simulations used time-dependent velocity and pressure boundary conditions in the transfer and exhaust ports, respectively, which were obtained from a one-dimensional gas exchange code. The bulk flow characteristics, scavenging and trapping efficiencies, computed from these simulations compared well with experimental data. Investigation of the highest load and speed case showed that moderate port angle variations only weakly influenced the scavenging efficiency and velocity field. On the other hand, modifying the exhaust pressure to simulate single cylinder operation had a more significant effect on the scavenging and showed a possible way to control the gas exchange process.
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